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HomeMy WebLinkAbout12-15-2021 Hearing Examiner AgendaHEARING EXAMINER December 15, 2021 5:30 p.m. The Auburn City Hearing Examiner Meeting scheduled for Wednesday, December 15, 2021 at 5:30 p.m. will be held virtually and telephonically. To attend the meeting virtually please click the below link, enter the meeting ID into the Zoom app, or call into the meeting at the phone number listed below. Per Governor Inslee's Emergency Proclamation 20-05 and 20-28 et. seq. and the City of Auburn Resolution No. 5581, City of Auburn has designated meeting locations as “virtual” for all Regular, Special and Study Session Meetings of the City Council and for the Committees, Boards and Commissions of the City. The link to the Virtual Meeting or Phone Number to listen to the Hearing Examiner is: Join Zoom Meeting https://us06web.zoom.us/j/85312021944 Meeting ID: 853 1202 1944 One tap mobile (253)215-8782 I.Case No:PLT19-0002 Carbon Trails Preliminary Plat Applicant(s): Barghausen Consulting Engineers, Inc. Jason Hubbell 18215 72nd Ave S. Kent, WA 98032 Property Owner: Stowe Investments LLC P.O. Box 1054 Sumner, WA 98390 Request: Preliminary plat application to subdivide approximately 11.37 acres into 44 single-family residential lots in the R-5, Residential, 5 dwelling units per acre zone. Project Location: The site is located between 51st Ave S and 56th Ave S, along the S 328th St right-of-way. Parcel No.: King County parcel numbers 9262800295, 9262800320, and 9262800313. 1 of 628 Page 2 2 of 628 AGENDA BILL APPROVAL FORM HEARING EXAMINER Agenda Subject/Title: PLT19-0002, Carbon Trails Preliminary Plat Date: December 3, 2021 Department: Community Development Budget Impact: Current Budget: $0 Proposed Revision: $0 Revised Budget: $0 DESCRIPTION: Preliminary plat application to subdivide approximately 11.37 acres into 44 single-family residential lots in the R-5, Residential, 5 dwelling units per acre zone. ADMINISTRATIVE RECOMMENDATION: Hearing Examiner to conduct a public hearing and approve the preliminary plat of Carbon Trails with 20 conditions and the associated Engineering Deviation Requests. PROJECT SUMMARY: Preliminary Plat of “Carbon Trails”, a 44-lot subdivision for the future construction of 44 single- family residences and associated site development activities. An existing residence on the site will be removed. As part of the Preliminary Plat, the applicant, has submitted two deviation requests to allow two separate retaining walls to be constructed within the S 328th St right-of- way. LOCATION: The site is located between 51st Ave S and 56th Ave S, along the S 328th St right-of-way, King County parcel numbers 9262800295, 9262800320, and 9262800313. PROPERTY OWNER: Stowe Investments LLC, P.O. Box 1054, Sumner, WA 98390 APPLICANT: Barghausen Consulting Engineers, Inc., Jason Hubbell, 18215 72nd Ave S, Kent, WA 98032 3 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 2 of 19 Subject Property and Adjacent Property Comprehensive Plan Designation, Zoning Classification and Current Land Use: Comprehensive Plan Designation Zoning Classification Current Land Use Project Site Single Family R-5 Residential Zone* Vacant & Single-Family Residence North Single Family R-5 Residential Zone* Vacant & Single-Family Residences South Single Family R-5 Residential Zone* Single-Family Residences East Single Family R-5 Residential Zone* Single-Family Residences West Single Family R-5 Residential Zone* Single-Family Residences *This area is also located within the West Hill Overlay, which was established as part of West Hill annexation in 2007, effective 2008. Excerpted Zoning Map: 4 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 3 of 19 555555555SEPA STATUS: A Determination of Non-Significance (DNS) was issued under City File No. SEP19-0003 on October 15, 2021, see Exhibit 4. The comment period ended October 30, 2021 and the appeal period ended November 15, 2021. The City received four comment letters/e-mails in response to the comment period. The comment(s) received along with the City responses are included as Exhibit 5. No appeal of the SEPA decision was received. FINDINGS OF FACT: Preliminary Plat Findings 1. Jason Hubbell, P.E., Barghausen Consulting Engineers, on behalf of Stowe Investments, Property Owner, submitted a Preliminary Plat application and associated SEPA application on January 18, 2019 to subdivide approximately 11.37 acres (referred to in this Staff Report as the “Site”) into 44 single-family residential lots, three private access tracts, one critical area tract, and one stormwater pond tract. An existing single-family residence located on the site will be removed. Please see Exhibit 6 for a copy of the preliminary plat and civil engineering plans. 2. A small portion of a Category III Wetland extends onto the northern portion of the site. The Category III wetland and its buffer will not be impacted, as no vegetation disturbance is proposed and hydrology to this wetland will be maintained. A copy of the applicant’s Critical Area Report, prepared by Sewall Wetland Consulting, is included as Exhibit 7. 3. The Site consists of three parcels located between 56th Ave S and 51st Ave S along S 328th St and is located in the West Hill portion of the City. The Site is located within the City of Auburn’s corporate limits and referenced by King County Tax Assessor Parcel No. 9262800295, 9262800320, and 9262800313. 4. The Site has a Comprehensive Plan designation of “Single Family Residential”. The entire site is currently zoned R-5, Residential, Five Dwelling Units Per Acre, which has a density range of between 4 and 5 dwelling units per acre. The site is approximately 11.37 acres, which would require between 45 and 57 lots. However, in accordance with the density calculation requirements specified in ACC 18.02.065(A)(5), the applicant seeks to have a lesser minimum density due to the critical area (Category III Wetland) located on the northern portion of the site. 5. The Project is subject to the zoning development standards for the R-5 zoning district in effect at the time the Project application was deemed “Complete” (i.e. vested). Per ACC 18.07.030 the zoning development standards for the R-5 zoning district include: • Minimum lot area: 4,500 square feet • Minimum lot width: 50 feet • Lot cot coverage: 40% • Impervious surface: 65% • Maximum building height: 35 feet • Minimum yard setbacks: o Front: 10 feet 5 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 4 of 19 o Side, interior: 5 feet o Side, street: 10 feet o Rear: 20 feet 6. Per ACC 18.52.020 two off-street parking spaces are required to be provided per future single family residence. 7. The Site currently has one single-family residence with associated outbuildings, all of which are proposed to be removed. 8. The project site is bordered by a “local” classified street (51st Ave S) to the west and a “residential collector” classified street (56th Ave S) to the east. The existing S 328th St right- of-way runs from east-to-west through the site between 51st Ave S and 56th Ave S. S 328th St will be developed with a public road that will serve the project and allow for an east-to- west connection between 51st Ave S and 56th Ave S. In addition to the public roads that will serve the project, access tracts to serve Lots 1-6, 15-19 and Lots 23-27. See Exhibit 6 for a copy of the plans, which includes the proposed road layout for the project. 9. The Site is located within the utility service areas of, and will be served by, Lakehaven Water and Sewer District for public water and sewer. The applicant provided both a certificate of water and sewer availability for the site. The certificates indicate that 1,820 feet of 12 or 8 inch sewer will need to be extended to the site and 20 feet of 8 inch water will need to be extended to the site. See Exhibit 6 for a copy of the conceptual utility plan for the project and Exhibit 14 for a copy of the Water and Sewer Availability Certificates. 10. Overall, the project slopes gradually from southeast to northwest. While there are no known Geologically Hazardous Areas on the property, the Applicant has provided the City with a Geotechnical Report with adequate information to show that the project will be in conformance with the City’s Engineering Design Standards. See Exhibit 8 for a copy of the Geotechnical Report provided by the applicant. 11. The Site is located within Groundwater Protection Zone 4, the least stringent classification. Therefore no impacts are anticipated that cannot be mitigated by utilizing Best Management Practices (BMPs) to comply with the code. As recommended in the Stormwater Site Plan Report (Exhibit 9), stormwater runoff from the Project will be evaluated, treated, and detained in a stormwater detention facility (‘stormwater pond’) located in Tract A, per the Department of Ecology Stormwater Management Manual for Western Washington (SWMM) and Auburn Supplements. 12. Per the Washington State Department of Archeology & Historic Preservation (DAHP) predictive model data, Washington Information System for Architectural & Archaeological Records Data (WISAARD) (https://dahp.wa.gov/wisaard), the site is located in a “Low Risk” area for archaeological resources. As such, a Cultural Resources Investigation was not prepared for this project. 13. Half-street improvements will be required along 56th Ave S. This includes any needed right- of-way dedications, curb, gutter, sidewalks, street lighting, stormwater controls, and landscape strips to meet the City’s “Residential Collector” standard. The S 328th St right-of- 6 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 5 of 19 way that runs through the project site will be improved with a fully paved City street with curb, gutter, and sidewalk on both sides. The northern portion of S 328th St within the western portion of the site will not have any new curb, gutter, or sidewalks added due to other properties abutting this area and separate from the project. 14. The applicant provided a Traffic Impact Analysis, prepared by TENW, dated July 1, 2021, confirming that the project will not result in any impacts to the City’s street network. Further, the impact fees collected for this project will directly support Transportation Improvement Projects (TIP) near the project that will further improve the City’s street network. The Traffic Impact Analysis is marked as Exhibit 10. 15. To mitigate increased demand for parks created by the Project, the current park impact fee shall be assessed at the time of building permit issuance in accordance with Chapter 19.08 ACC ‘Parks Impact Fees’. 16. To mitigate increased demand for schools created by the Project, the current school impact fee shall be assessed at the time of building permit issuance in accordance with Chapter 19.02 ACC ‘School Impact Fees’. 17. To mitigate increased demand for fire/emergency services generated by the Project, payment of the fire impact fee in effect at the time of building permit issuance is required in accordance with Chapter 19.06 ACC ‘Fire Impact Fees’. 18. To mitigate increased PM peak hour trips generated by the Project, a traffic impact fee in accordance with the City of Auburn Traffic Impact Fee Schedule shall be assessed at building permit issuance in accordance with Chapter 19.04 ACC ‘Transportation Impact Fees’. 19. A Notice of Application and Determination of Non-Significance (DNS) was issued on October 15, 2021, and November 12, 2021 (Exhibit 4). Further, the Notice of Public Hearing was issued on xx, 2021. The notices were posted at the Site, mailed to property owners within 300 ft. of the Site, and published in The Seattle Times newspaper. 20. In response to the Notice of Application, DNS and Notice of Public Hearing, the City received four comment letters as of December 3, 2021 (the date this Staff Report was prepared) on the project. What follows is Staff’s abbreviated summary of the comment(s) received along with a short summary of the City’s response, if one was necessitated. The full set of comments and any response from the City are marked as Exhibit 5. a. Puget Sound Clean Air Agency: commented that any demolition of structures, earth moving activities, vegetation removal, or heavy equipment operation may be subject to Puget Sound Clean Air Agency regulations. City Response: Staff acknowledges that the proposed work may require additional permitting and/or review from the PSCAA. The comment was provided to the applicant for their information. b. Bryan Peterson & Danielle Zaklan (32720 51st Ave S, Auburn, WA 98001): requested that they be informed of any hearings and be included as a party of record. 7 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 6 of 19 City Response: Staff have provided information for the public hearing and noted that the commentor will receive a copy of the decision when it is issued. c. Frances Wold (5604 S 328th St, Auburn, WA 98001): commented that the existing trees directly to the west of 56th Ave S along the southeast portion of the project site provide numerous shade and wind protection benefits to her property. As such, Ms. Wold requests that these trees be preserved. City Response: City staff acknowledge the numerous benefits that large trees can provide. However, staff responded to Ms. Wold and noting that the City does not have a tree protection ordinance in place. Ms. Wold’s comments were provided to the applicant, should they elect to preserve any trees on the project site. d. Stacy Kanda (32712 51st Ave S, Auburn, WA 98001): commented that the project will result in significant traffic to the area, with potential to impact nearby intersections, that the site has larger wetland areas than what is depicted on the plans, that the proposed stormwater management system should contain additional protections to ensure no impacts to the nearby wetlands and Mill Creek, that there will be impacts to nearby wildlife, that there will be negative aesthetic impacts resulting from the proposal, that crime may increase from the proposal, and that the S 328th St connection will have a huge impact on safety and quality of life in the neighborhood. City Response: City staff responded to Stacy Kanda noting that the project has been designed to meet the current Western Washington Stormwater Management Manual, that there are no known endangered species on the site, that the critical areas on the site will be protected, and that the proposal will meet current zoning code requirements ensuring that City aesthetic standards are met. 21. In accordance with ACC 18.02.130, the applicant conducted a Neighborhood Review Meeting on January 9, 2019 to discuss the project. According to the summary provided by the applicant, the neighbors had questions regarding the overall design and layout of the development, including how stormwater will be managed, what road improvements will be completed, and how large the lot sizes will be. The applicant was able to respond to the questions raised by the public. Of particular note is how the construction of S 328th St where it ties into 51st Ave S will impact the nearby property owners. The applicant acknowledged many of the design challenges associated with improving 51st Ave S. The comments and public meeting materials are included as Exhibit 13. 22. There are various elements of the proposed development that do not meet the City of Auburn Engineering Design Standards, Standard Details and Stormwater Management Manual. The major elements that potentially impact the overall plat layout have been addressed with the Preliminary Plat approval however, many elements were requested to be deferred until the civil site improvement submittal. The future civil site improvement submittal will be required to conform to all requirements in the City of Auburn Engineering Design Standards, Code, Standard Details and Surface Water Management Manual. Deviation Findings 8 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 7 of 19 1. The applicant submitted two requests for “deviations” from the City of Auburn Engineering and Design Standards (COADS) to allow for two separate retaining walls to be constructed within the S 328th St right-of-way (City File No. DEV21-0035 & DEV21-0036, Exhibit 13). 2. Deviations from the COADS are subject to approval of the Hearing Examiner per ACC 17.18.010(A) and COADS 1.04 which state (emphasis added): “ACC 17.18.010(A). The hearing examiner may approve a modification of any standard or specification established or referenced by Chapter 17.14 ACC or established or referenced in the city’s design standards or construction standards, upon making the findings of fact in ACC 17.18.030; provided, that the hearing examiner shall obtain the concurrence of the city engineer for any requests to modify any city of Auburn design or construction standard.” “COADS 1.04. For deviation applications that are associated with a preliminary plat application submitted in compliance with Chapter 17.10 ACC, the deviation application and a recommendation from the City Engineer must accompany the preliminary plat to the hearing examiner.” 3. The City Engineer has reviewed the Deviation requests and conditionally recommends approval, under ‘Recommended Conditions of Approval’, below. CONCLUSIONS: Preliminary Plat Conclusions Per ACC 14.03.030, a preliminary plat is a Type III Decision which are quasi-judicial final decisions made by the Hearing Examiner. ACC 17.10.070 ‘Findings of Fact’ lists the approval criteria for a preliminary plat. A comparison of the project’s relationship to subdivision approval criteria are as follows (in italics) followed by a Staff analysis: A. Adequate provisions are made for the public health, safety and general welfare and for open spaces, drainage ways, streets, alleys, other public ways, water supplies, sanitary wastes, parks, playgrounds and schools; Staff Analysis: No adverse impacts to the public health, safety and general welfare are anticipated from the proposed subdivision. Staff offers the following analysis of each of subcategory listed in this criterion: Open Spaces: The project will be designed to meet the setback and lot coverage requirements of the R-5 Residential Zone. Further, existing critical areas that extend onto the site will be preserved. Through meeting the R-5 Residential Zone standards and critical area protection standards, the site will be preserving the minimum open space necessary to serve the project. Drainage Ways: Through the civil plan review process, the stormwater runoff from the Project will be evaluated, treated, and detained in a stormwater pond located in Tract A, Division I, per the Department of Ecology Stormwater Management Manual for Western 9 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 8 of 19 Washington (SWMM) and Auburn Supplements. Additionally, hydrology to the existing Wetland will be maintained. Streets, Alleys, other Public Ways: The Project will be required to construct streets per ACC, Chapter 12.64A ACC ‘Required Public Improvements’, the City’s Engineering Design Standards, and the Comprehensive Transportation Plan. With the full buildout of S 328th St and the half-street improvements to 56th Ave S, the City’s Transportation Division finds that there will be no decrease in the road network level of service (LOS) standard. Additionally, the Traffic Impact Fee in place will be paid for each building permit issuance. More specifically, roadways will be constructed concurrent with the plat as follows: 1. Half-street improvements in accordance with ACC 12.64A to the Site’s frontage on 56th Ave S, as depicted on the preliminary plat plans. Such improvements are generally limited to the addition of new sidewalk and pavement restoration. Design of such improvements will be finalized during the FAC review. 2. S 328th St will be constructed, east-west, from 56th Ave S to 51st Ave S. Full street improvements to the city’s “Local Residential” standard will be required, including a full-width paved roadway (28 ft.), curb, gutter, sidewalks, street lighting, stormwater controls, and landscape strips. 3. Tract C is a private access tract featuring a paved width of 20 feet (tract is 26 ft. in width) with five-foot sidewalk located on one side. Tract C will tie into S 328th St. Six lots will take access from this private access tract, including lots 22 through 25. 4. Tract D is a private access tract featuring a paved width of 20 feet (tract is 26 ft. in width) with five-foot sidewalk located on one side. Tract C will tie into S 328th St. Five lots will take access from this private access tract, including lots 15 through 19. 5. Tract E is a private access tract featuring a paved width of 20 feet (tract is 26 ft. and 31 ft. in width) with five-foot sidewalk located on one side, with some portions having sidewalk on both sides. Tract E will tie into S 328th St. Six lots will take access from this private access tract, including lots 1 through 6. Based on the City’s Comprehensive Transportation Plan, Functional Roadway Classification Map, the creation of S 328th St will be a “Local Residential” street. Public Water: The Site is located in the Lakehaven Water and Sewer service area. Adequate water service will be provided for the Project. Water will be extended from the existing water mains in 51st Ave S and 56th Ave S to serve the project. Public Sanitary Sewer: The Site is located in the Lakehaven Water and Sewer service area. Adequate sanitary sewer service will be provided for the Project. Sanitary sewer service will be extended through the plat from the intersection of S 324th St and 46th Pl, roughly 1,820 feet northwest of the site. Parks, Playgrounds: While the project size doesn’t rise to the level to require park dedication, which includes projects involving 50 or more lots, Evergreen Heights 10 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 9 of 19 Elementary, a public school owned and managed by the Auburn School District, provides playground facilities for public use. Evergreen Heights is located within ½ mile of the project, to the north. Additionally, each of the newly constructed residences will be required to pay park impact fee, with such money be reserved for future park and recreation related projects in the West Hill area. Schools: The Site is located within the Auburn School District (ASD) boundary. Per the Applicant, students within the Project will attend: 1) Evergreen Heights Elementary School; 2) Cascade Middle School, and 3) Auburn High School. All students that will reside within the project will be bused to their respective schools. Existing bus stops at the intersection of S 328th St - 56th Ave S and 51st Ave S – 46th Pl will be used. See Exhibit 11 for the applicants school walking and bussing analysis. Staff therefore finds the Project meets this criterion, as conditioned herein. B. Conformance of the proposed subdivision to the general purposes of the comprehensive plan; Staff Analysis: The Project is consistent with the general purposes of the Comprehensive Plan. The Comprehensive Plan Map establishes the future land use designations for the City of Auburn. The designation of ‘Single Family Residential’ establishes areas intended for single family dwellings. The Comprehensive Plan Map depicts the Site as ‘Single Family Residential’. The Project will subdivide 11.37 acres into 44 lots for single-family dwellings. Therefore this Project meets the intent of the Comprehensive Plan by developing single- family dwellings. Additionally, adequate City services and facilities can be provided to serve the plat. Lakehaven utilities, such as sewer and water will be extended to serve the proposed Project. The Project will also provide adequate facilities for stormwater; all stormwater will be directed to the stormwater detention facility (‘stormwater pond’) pond located in the south portion of the site. The stormwater pond will be required to meet applicable code and engineering design standards, as conditioned below. S 328th St, a new “Local Residential” public street will be constructed, along with private access tracts, to serve the proposed Project. Sidewalks will be constructed on both sides of the new street. Public services such as the Auburn Police Department, Valley Regional Fire Authority, and the Auburn School District will also serve the proposed Project. Finally, traffic, fire, parks, and school impact fees will mitigate respective impacts generated by the Project. The Project is also consistent with or implements the specific following goals, objectives, and policies of the Comprehensive Plan: Land Use Policies: “LU-5 New residential development should contribute to the creation, enhancement and improvement of the transportation system, health and human services, emergency services, school system, and park system. This may be accomplished through the development of level of service standards, mitigation fees, impact fees, or construction contributions.” 11 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 10 of 19 Capital Facilities “Objective 1.1. To ensure that new development does not out-pace the City's ability to provide and maintain adequate public facilities and services, by allowing new development to occur only when and where adequate facilities exist or will be provided, and by encouraging development types and locations which can support the public services they require.” Policies: “CF-1 Lands designated for urban growth by this Plan shall have an urban level of public facilities (sewer, water, storm drainage, and parks) prior to or concurrent with development.” “CF-2 Encourage development where new public facilities can be provided in an efficient manner.” “CF-4 If adequate facilities are currently unavailable and public funds are not committed to provide such facilities, developers must provide such facilities at their own expense in order to develop.” “CF-7 The City shall encourage and approve development only where adequate public services including police protection, fire and emergency medical services, education, parks and other recreational facilities, solid waste collection, and other governmental services are available or will be made available at acceptable levels of service prior to project occupancy or use.” Transportation Plan “Connect-01: An efficient transportation system seeks to spread vehicle movements over a series of planned streets. The goal of the system is to encourage connectivity while preventing unacceptably high traffic volumes on any one street. Ample alternatives should exist to accommodate access for emergency vehicles. For these reasons the City will continue to plan a series of collectors and arterials designed to national standards to provide efficient service to the community.” “Funding-01: Require developments or redevelopments to construct transportation infrastructure systems needed to serve new developments.” “Funding-03: Improvements that serve new developments will be constructed as a part of the development process. All costs will be borne by the developer when the development is served by the proposed transportation improvements. In some instances, the City may choose to participate in this construction if improvements serve more than adjacent developments.” “Parking-02: New developments should provide adequate off-street parking to meet their needs.” 12 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 11 of 19 “ROW-01: The acquisition and preservation of right-of-way is a key component of maintaining a viable transportation system. Methods used to acquire and preserve right-of- way include: • Requiring dedication of right-of-way as a condition of development; • Purchasing right-of-way at fair market value; and • Acquiring development rights and easements from property owners.” “Ped-03: Require developers to incorporate pedestrian facilities into new development and redevelopment in conformance with the Auburn City Code.” Parks, Recreation, and Open Space Plan “PR-8 Park impact fees should be established that help fund the future development of new parks, park facilities, trails, and acquisition of open space that meet the needs of an increasing population.” C. Conformance of the proposed subdivision to the general purposes of any other applicable policies or plans which have been adopted by the city council; Staff Analysis: The preceding analysis for Criterion B demonstrates the Project’s consistency with the applicable policies and objectives of the Comprehensive Plans adopted by the City. The project is generally consistent with the policies of the Comprehensive Plan including the City of Auburn Capital Facilities Plan, Comprehensive Transportation Plan, and the Parks, Recreation, and Open Space Plan. D. Conformance of the proposed subdivision to the general purposes of this title, as enumerated in ACC 17.02.030; Staff Analysis: The proposed subdivision meets the general purposes of Title 17 ACC ‘Land Adjustments and Subdivisions’. The Carbon Trails Preliminary Plat is a 44-lot subdivision that is consistent with the R-5 zoning district. Adequate provisions for water, sewer, storm drainage, roads, and safe walking conditions will be provided with this Project. The plat has been processed and reviewed for conformity with the regulations for the Auburn City Code, city plans and policies, and engineering design standards. Below is a comparison of the Project’s consistency with ACC 17.02.030 and the specific purpose statements of the subdivision code (in italics) followed by a Staff analysis for each item. “The purpose of this title is to regulate the division of land lying within the corporate limits of the city, and to promote the public health, safety and general welfare and prevent or abate public nuisances in accordance with standards established by the state and the city, and to: A. Prevent the overcrowding of land; Staff Analysis: The Project meets the minimum and base density of the R-5 zoning district. As provided under ‘Finding of Fact’ No. 4, the R-5 zoning district has a density 13 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 12 of 19 range of between 4 and 5 dwelling units per acre. As the site is approximately 11.37 acres, which based on the density calculation requires between 45 and 57 lots. As proposed, the Project will contain 44 lots, 1 lot less than the minimum density for the R-5 zoning district. Per ACC 18.02.065(A)(5), projects that cannot meet the minimum density requirement of their respective zone due to the presence of a critical area may deviate from the minimum density requirement. Staff finds that in this instance, the applicant has maximized the development potential of the property while providing the necessary infrastructure improvements and critical area protections required by other City codes and policies. Additionally, the Project will not create an overcrowding of the land. Therefore, the request to deviate from the minimum density requirement of 45 units to 57 units is appropriate in this instance. B. Promote safe and convenient travel by the public on streets and highways; Staff Analysis: The Project is constructing a new road, including pedestrian access, within the S 328th St right-of-way and therefore will provide a means of safe and convenient travel via public routes. C. Promote the effective use of land; Staff Analysis: The Project is effectively developing the Site by maximizing the number of residential units that are allowed for the R-5 zoning district while preserving existing onsite critical areas and providing mitigation. D. Provide for adequate light and air; Staff Analysis: The Project will provide adequate light and air through the applicable setback and lot coverage development standards. E. Facilitate adequate provision for water, sewerage, storm drainage, parks and recreational areas, sites for schools and school grounds, and other public requirements; Staff Analysis: The Finding of Facts, and preceding analysis for Criteria A and B demonstrates the Project is providing adequate provisions for water supplies, sanitary wastes, drainage, roads, and other public requirements such as public health, safety, parks, and schools. F. Identify, preserve, and utilize native soils and/or vegetation for the purposes of reducing storm water discharges, promoting groundwater infiltration, and implementing the use of storm water low impact development techniques; Staff Analysis: The Site gently slopes from southwest to northeast. With the exception of the Wetland located to the north, the Site will be cleared of vegetation and graded in preparation of the placement of site improvements such as the development of new roads, creation of a stormwater detention facility, home sites, and the installation of utilities. Per the applicant’s Geotechnical Report (Exhibit 8), infiltration will not be feasible for this site. As a result, there are limited opportunities to manage stormwater on site through infiltration and other low impact development techniques. However, 14 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 13 of 19 preservation and the creation of additional wetland area along the northern portion of the site will help contribute towards preservation of existing native vegetation and soils. Finally, as required by the R-5 zoning district, the subsequent development of each lot will be held to a maximum of 40% lot coverage and 65% impervious surface coverage. G. Provide for proper ingress and egress; Staff Analysis: As demonstrated in the analysis for Criterion A, the Project will provide proper ingress and egress for each individual future home. H. Provide for the expeditious review and approval of proposed land divisions which comply with this title, the Auburn zoning ordinance, other city plans, policies and land use controls, and Chapter 58.17 RCW; Staff Analysis: Staff has worked with the applicant to ensure a timely and comprehensive review of the Project. I. Adequately provide for the housing and commercial needs of the citizens of the state and city; Staff Analysis: The Project will eventually provide for 44 new single-family residences to serve future residents. An existing single-family residence will be removed. J. Require uniform monumenting of land divisions and conveyance by accurate legal description; Staff Analysis: Upon final plat map review, the Project will be required to meet all applicable survey requirements. K. Implement the goals, objectives and policies of the Auburn Comprehensive Plan.” Staff Analysis: As analyzed in Criterion B, the Project successfully implements the Comprehensive Plan. Staff therefore finds the Project meets this criterion, as conditioned herein. E. Conformance of the proposed subdivision to the Auburn zoning ordinance and any other applicable planning or engineering standards and specifications as adopted by the city, or as modified and approved as part of a previously approved PUD; Staff Analysis: As analyzed in the ‘Preliminary Plat Findings’, above, the Project is able to meet applicable zoning and engineering standards, with the exception of the engineering deviation (retaining walls in right-of-way), which are discussed under ‘Engineering Deviation Conclusions’ provided below. The placement of homes will be required to meet the zoning development standards for the R-5 zoning district to which the Project is vested. 15 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 14 of 19 Staff therefore finds that the Project is able to meet this criterion, as conditioned herein. F. The potential environmental impacts of the proposed subdivision are mitigated such that the preliminary plat will not have an unacceptable adverse effect upon the quality of the environment; Staff Analysis: Per the Critical Area Report (Exhibit 7), the site contains one Category III Wetland identified on the Site. No vegetation disturbance will occur on this wetland while hydrology to it will remain. The applicant also provided a Geotechnical Report (Exhibit 8), confirming that there are no geologic hazardous areas within the project site. The site will be required to meet any applicable building, engineering, and any other local, state, or federal standard that relating to grading, erosion control, and slope stability. The Site is also located within Groundwater Protection Zone 4, which is the least stringent classification. With the utilization of Best Management Practices, it is anticipated that potential impacts to groundwater can be mitigated. A Determination of Non-Significance was issued on October 15, 2021 for this Project. Compliance with the recommended conditions of approval, city code, and engineering design standards will ensure that the Project will not have an adverse impact on the environment. During civil plan review process, the Project will be reviewed in accordance with applicable local, state, and federal standards to ensure no unacceptable adverse impacts to the environment occur. Staff therefore finds the Project meets this criterion, as conditioned herein. G. Adequate provisions are made so the preliminary plat will prevent or abate public nuisances; Staff Analysis: Adequate provisions are made, and will be made through the subsequent civil plan review process, so the proposed Project will prevent or abate public nuisances. As the Site is mainly undeveloped, there are no active code violation cases for the site and no known public nuisances. Staff therefore finds the Project meets this criterion, as conditioned herein. H. Lot configuration, street and utility layouts, and building envelopes shall be designed in a manner that identifies, preserves, and utilizes native soils and/or vegetation that are integrated into a low impact development facility, consistent with the city’s adopted storm water management manual. Staff Analysis: As analyzed in Criteria A, B, and D above, the Project has been designed such that it will be consistent with the City’s Engineering Design Standards and the 16 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 15 of 19 Department of Ecology Stormwater Management Manual for Western Washington (SWMM) and Auburn Supplements. Staff therefore finds the Project meets this criterion, as conditioned herein. Engineering Deviation Conclusions Per ACC 17.18 ‘Modifications of Standards and Specifications’, the Hearing Examiner may approve a modification of any standard or specification established or referenced by Chapter 17.14 ‘Improvement Requirements – Subdivisions’, or referenced in the city’s design standards or construction standards. Further, the City Engineer shall make a recommendation to the Hearing Examiner on any modifications requested from the City of Auburn Engineering Design Standards (COADS). This process is referred to as a “Deviation” per Section 1.04 of the COADS. Two Deviations were requested: 1. DEV21-0035 – Construction of a retaining wall in the right of way supporting a public sidewalk (COA Engineering Design Standards Sections 5.04 and 10.01.03). 2. DEV21-0036 – Construction of a retaining wall in the right of way supporting private property (COA Engineering Design Standards Section 5.04). The City Engineer has reviewed the Deviation Requests (DEV21-0035 & DEV21-0036) submitted for the Carbon Trails Preliminary Plat (PLT19-0002). The results of that review are provided below. DEV21-0035: Applicant requests approval of the construction of a retaining wall adjacent to a public sidewalk and located within the right of way. The proposed retaining wall will structurally support the public sidewalk. The request addresses specific criteria for deviation requests from Section 1.04 of the City of Auburn Engineering Design Standards (EDS) in the following way: - 1.04.01.B Safety factors associated with the design element: Fall protection fencing will be provided at the top of the wall adjacent to the sidewalk. - 1.04.01. D Maintenance concerns associated with the design element: The Carbon Trails Homeowners Association will assume maintenance responsibility for the wall, wall footing drains, landscaped slopes, fall protection fencing, and all other appurtenances of the wall. - 1.04.01.E Liability concerns associated with the design element: Liability will be assumed by the Carbon Trails Homeowners Association by taking on the maintenance responsibilities of the wall. Fall protection fencing will address the liability concerns associated with pedestrian safety in the section of sidewalk where the wall is adjacent. 17 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 16 of 19 Section 5.04 of the EDS indicates that retaining walls that support/retain the public right of way will be located within the public right of way and be owned and maintained by the City. Section 10.01.03 of the EDS requires that a 2 foot flat area behind the sidewalk, with a max 2:1 slope adjacent to the flat area. DEV21-0036: Applicant requests approval of the construction of a retaining wall adjacent to a privately owned parcel and located within the right of way. The proposed retaining wall will structurally support land outside of the public right of way. The request addresses specific criteria for deviation requests from Section 1.04 of the City of Auburn Engineering Design Standards (EDS) in the following way: - 1.04.01.B Safety factors associated with the design element: Fall protection fencing will be provided at the top of the wall adjacent to the private property. - 1.04.01. D Maintenance concerns associated with the design element: The Carbon Trails Homeowners Association will assume maintenance responsibility for the wall, wall footing drains, landscaped slopes, fall protection fencing, and all other appurtenances of the wall. Graffiti resistant surfacing will be provided on the face of the wall. - 1.04.01.E Liability concerns associated with the design element: Liability will be assumed by the Carbon Trails Homeowners Association by taking on the maintenance responsibilities of the wall. Fall protection fencing will address the liability concerns associated with the private property adjacent to the wall. Section 5.04 of the City of Auburn Engineering Design Standards (EDS) indicates that retaining walls that support/retain land outside of the public right of way will be located outside of the public right of way and be owned and maintained by the owner of the land the retaining wall is supporting. City Engineer Response to Deviation Requests DEV21-0035 and DEV21-0036: • The City Engineer may grant a deviation from the EDS if the applicant demonstrates that the proposed deviation will meet or exceed the corresponding City standard for the criteria listed in Section 1.04.1 of the EDS. • In the case of the request to deviate from Sections 5.04 and 10.01.03 of the EDS (DEV21-0035), the City Engineer has determined that the proposal meets or exceeds the corresponding City standards 1.04.01 B, D, and E for the reasons listed above. • In the case of the request to deviate from Section 5.04 of the EDS (DEV21-0036), the City Engineer has determined that the proposal meets or exceeds the corresponding City standards 1.04.01 B, D, and E for the reasons listed above. Based on the above, the request to deviate from Sections 5.04 and 10.01.03 of the EDS for DEV21-0035 and DEV21-0036 are conditionally approvable by the City and will be 18 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 17 of 19 recommended for conditional approval to the Hearing Examiner, subject to the conditions of approval, below. STAFF RECOMMENDATION: Staff recommends approval of the Carbon Trails Preliminary Plat and the Engineering Deviation requests, subject to the information contained in this Staff Report, the attached exhibits, and the 20 recommended conditions of approval below. RECOMMENDED CONDITIONS OF APPROVAL: 1. Prior to City approval of the civil plans under the FAC, the Applicant must provide documentation of submittal of an application to the Washington State Department of Ecology for a Construction Stormwater General Permit, as required for all projects over 1 acre in size. 2. Fencing shall be provided around the perimeter of the stormwater pond, the location of which will be reviewed and determined during the FAC review and the fencing shall be consistent with current City Standards. 3. As part of the civil plans a landscaping plan for the publicly dedicated stormwater pond shall be provided for City review and approval. The type and location of landscaping shall be coordinated with the location and type of fencing installed in the stormwater tract. The stormwater tract landscaping design must meet all applicable vehicle site distance requirements. 4. A note shall be placed on the Final Plat indicating that the HOA shall be responsible to regularly maintain those portions of the stormwater pond (Tract A) outside of the fenced perimeter of the stormwater pond, as determined by the City Engineer. Additionally, the Covenants, Conditions, and Restrictions (CC&R's) that are reviewed and approved by the City at Final Plat application, and as recorded thereafter, shall establish the HOA's responsibility for regular landscape maintenance. 5. Tracts C, D, and E are private access and utility tracts and will be owned and maintained by the HOA. A note shall be placed on the Final Plat that the HOA is responsible for maintenance including associated walkways, signage, and other associated features. 6. If groundwater is encountered during construction in the proposed detention pond that appears to impact the live storage capacity of the detention pond, the City of Auburn will stop construction and require redesign of the facility as necessary to account for observed groundwater. Depending on the groundwater seepage rates encountered, elevations observed, the time of year, and other possible factors, construction may not commence again until updated civil plans showing a revised pond design is prepared, submitted, and approved by the City of Auburn. 7. Prior to City approval of the civil plans under the City of Auburn Facilities Extension Agreement (FAC), the plans shall show that appropriate portions of public streets shall be posted “No Parking” due to its road width or presence of medians. The posting shall be in 19 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 18 of 19 accordance with the City of Auburn Engineering Design Standards. 8. Per section 7.06.03 of Auburns Engineering and Design Standards for fire flow, minimum fire flow for a home up 3,600 sq. ft. require 1,500 GPM for 2 hours. Homes over this size, the fire flow will be calculated from Appendix B of the IFC. 9. The water certificate provided from Lakehaven Water District indicates the water availability is 1,000 GPM for 2 hours. This does not meet City of Auburn minimum standards. The installation of a 13D fire sprinkler system in the homes can mitigate this requirement. Fire flow for a home with a fire sprinkler system will be adjusted by 50% but not below 750 GPM for 2 hours. 10. The Site is in the City’s identified Groundwater Protection Zone 4. All approvals and permits related to the Project and issued by the City shall be consistent with best management practices (BMPs) per ACC 16.10.120(E)(2). 11. Tract A is a stormwater management tract that will be owned and maintained by the future HOA for the development. 12. Tract B is a wetland/open space tract that will be owned and maintained by the future HOA for the development. Tract B shall be protected by a conservation easement or similar protection method acceptable to the City in accordance with ACC 16.10. 13. Tract C is a private access tract and will be owned and maintained by Lots 22-25 or the future HOA for the development. 14. Tract D is a private access tract and will be owned and maintained by Lots 15-19 or the future HOA for the development. 15. Tract E is a private access tract and will be owned and maintained by Lots 1-6 or the future HOA for the development. Deviation Request Conditions of Approval 16. Final design of the walls and all components, including structural design, shall be completed during the Facility Extension (FAC) civil review for the project. 17. Design of the walls shall include fall protection fencing on the top of the walls. 18. Ownership and maintenance of the walls, slopes adjacent to the walls, footing drains, fall protection fencing, and other appurtenances shall be the responsibility of the Carbon Trails Homeowner’s Association and its successors/heirs. Maintenance shall include repair and replacement of the wall, fall protection fencing, and other wall appurtenances. 19. The Carbon Trails Homeowner’s Association and its successors/heirs shall obtain a Type C Right of Way Use permit or its equivalent for the privately owned walls in the public right of way, and renew this permit upon expiration in perpetuity. 20 of 628 Staff Member: Dustin Lawrence Date: December 3, 2021 Page 19 of 19 20. Please revise the preliminary plat plans to include the required deviation request notes and callouts per Chapter 3, Appendix C of the EDS and resubmit the plans for confirmation. Staff reserves the right to supplement the record of the case to respond to matters and information raised subsequent to the writing of this report ATTACHMENTS: Exhibit 1. Staff Report Exhibit 2. Vicinity Map Exhibit 3. Completed Preliminary Plat Application Forms, prepared Barghausen Consulting Engineers, dated January 17, 2019 Exhibit 4. Notice of Application and Determination of Non-Significance. Includes the Final Staff Evaluation & Environmental Checklist Exhibit 5. Four Written Public Comment(s) Received and City Response(s) Exhibit 6. Preliminary Plat and Civil Plans, Barghausen Consulting Engineers, Inc., dated October 28, 2021 Exhibit 7. Critical Area Report, Sewall Wetland Consulting, dated January 14, 2019 Exhibit 8. Geotechnical Report, GeoResources, dated January 14, 2019 Exhibit 9. Stormwater Site Plan, Barghausen Consulting Engineers, dated April 30, 2021 Exhibit 10. Traffic Impact Analysis, TENW, dated July 1, 2021 Exhibit 11. School Walkway Analysis, Barghausen Consulting Engineers, dated April 30, 2021 Exhibit 12. Engineering Deviation Requests, Barghausen Consulting Engineers, dated October 7, 2021 Exhibit 13. Neighborhood Meeting Materials, Barghausen Consulting Engineers, dated January 3, 2019 Exhibit 14. Water & Sewer Availability Certificates, Lakehaven Water & Sewer District, dated October 31, 2018 Prepared by Dustin Lawrence, AICP, CFM 21 of 628 666.7 NAD_1983_StatePlane_Washington_North_FIPS_4601_Feet Feet666.7333.30 Vicinity Map 11/30/2021Printed Date: Map Created by City of Auburn eGIS Imagery Date: May 2015 Information shown is for general reference purposes only and does not necessarily represent exact geographic or cartographic data as mapped. The City of Auburn makes no warranty as to its accuracy. 22 of 628 Form Updated May 2018 1 CITY OF AUBURN PRELIMINARY SUBDIVISION (PLAT) Planning & Development Department APPLICATION PACKET Auburn City Hall Annex, 2nd Floor 1 East Main Street / Auburn, WA 98001 Tel: (253) 931-3090 / Fax: (253) 804-3114 permitcenter@auburnwa.gov / www.auburnwa.gov PRELIMINARY SUBDIVISION (PLAT) APPLICATION INTRODUCTION (TYPE III DECISION) What does Type III refer to? Type III land use and land division decisions are also referred to as quasi-judicial decisions made by the City of Auburn Hearing Examiner following a public hearing. The Hearing Examiner is responsible by City Code to interpret, review, and implement land use, land division, and ot her ordinances and regulations. City staff conducts an initial review of the application and submits a written recommendation to the City’s Hearing Examiner who conducts the public hearing. Interested citizens can participate by giving written or verbal comments on a proposed project or issue. Following the public hearing, the Hearing Examiner issues a written decision that can be appealed to the Superior Court of the county in which the property is located (King County or Pierce County). What is a Subdivision? A subdivision is the land use process that provides general approval of division or re-division of land into 10 or more lots, tracts, parcels, sites, or divisions for the purpose of sale, lease, or transfer of ownership or development. A subdivision may be used to create conventional lots in residential or commercially zoned areas, clustered residential subdivision lots, or small lot infill development. What is a Preliminary Plat? A preliminary plat is a neat and approximate drawing of a proposed subdivision showing the layout of streets, alleys, lots, blocks, utilities and other elements of a subdivision consistent with RCW 58.17 and provisions of Auburn City Code (ACC) 17.10 (Preliminary Subdivisions). What are the Minimum Requirements for stormwater management? The City is required to implement Minimum Requirements for stormwater management on all new development and redevelopment projects, including short subdivisions. The Minimum Requirements are presented in the City of Auburn Surface Water Management Manual and must be addressed in accordance with the applicable provisions of ACC 13.48. The Minimum Requirements that must be addressed early in the planning of a preliminary plat are:  #5 – On-Site Stormwater Management (Low Impact Development [LID])  #6 – Runoff Treatment  #7 – Flow Control  #8 – Wetlands Protection  #10 – Off-Site Analysis and Mitigation Can you cluster lots within a subdivision? In certain areas of the City, the City of Auburn allows clustering of lots within a subdivision onto a portion of the site, while maintaining the density. Clustering allows future development to occur at an appropriate density and location for infrastructure services; it also protects environmentally critical areas or cultural/historic features by clustering lots away from these areas. The standards by which clustering is allowed is set forth in ACC 17.26. 23 of 628 Form Updated May 2018 2 When is a neighborhood review meeting required? Per ACC 18.02.130, neighborhood review meetings are required for a residential subdivision project comprising forty (40) or more lots or units; or multi-family residential projects comprising forty (40) or more units; or mixed-use development projects comprising forty (40) or more units. How long before I am notified if my application is complete? At the time you submit an application, you must submit all of the written and plan information listed in this application under “Type III Subdivision Application Submittal Checklist”. Within 28 calendar days of receiving your application, City staff will determine if the application is complete based on the attached checklist. If your application is complete you will be notified in writing by City st aff. If your application is incomplete, you will receive a letter from City staff detailing required information to make it complete. What are the criteria for preliminary plat approval? The preliminary plat must conform to general requirements for subdivision including ACC 17.10.070 (Findings of Fact) and RCW 58.17.110 (Factors to be considered and Findings). What is SEPA and when is it applicable? Preliminary plats may be subject to compliance with the Washington State Environmental Policy Act (SEPA) based on the presence of critical areas; proposed grading, required licensing for air emissions or discharges to water; or other factors. If subject to SEPA, an environmental checklist must be submitted with the preliminary plat application. After the Notice of Application comment period expires, the Planning Director – who is the City’s SEPA Responsible Official - issues a SEPA threshold determination (TD), or other SEPA decision as provided in ACC 16.06, RCW 43.21 and WAC 197-11. The SEPA decision is final unless the TD is appealed or the City revises the TD based on further comments during the appeal period. The appeal period is 14 days for a determination of non-significance and 21 days for a mitigated determination of non-significance. If appealed, the appeal must be filed with the City Clerk per ACC16.06.230 and it will be heard by the Hearing Examiner pursuant to ACC 18.66.130. If the SEPA Responsible Official issues a Determination of Significance (DS) because of probable significant impacts by the proposal, an Environmental Impact Statement (EIS) will be required before the City makes any decision on this application. What if there are CRITICAL AREAS on the property? Projects that involve work within or adjacent to critical areas (e.g., wetlands, streams, steep slopes, ground water protection areas) may require that the City contract out for expert technical assistance. Pursuant to ACC 16.10, the applicant is responsible for providing any information, mapping, studies, materials, and for paying for inspections or review by a qualified professional acceptable to the City. You will be advised at the earliest possible point if your project will be subject to these types of expenses. What happens after a preliminary plat is approved? Preliminary plat approvals are valid for a period of five years following the date of the notice of final decision (ACC 17.09.110 Time limitations). After preliminary approval is granted, engineering design and construction in compliance with ACC 17.14/Improvement Requirements, must be completed and conditions of preliminary plat approval satisfied. Then an application for final plat can be submitted to the City for review. Once City staff confirms that all conditions and requirements have been met, the final plat is forwarded to the City Council for approval. Following City Council approval, the final plat will be recorded by the City with the county recorder’s office. What are Impact Fees? Impact Fees are fees associated with new development to mitigate the impacts of the development. Impact fees are typically assessed and required to be paid at the time of building permit(s) issuance. Such fees may include fees when there is an associated impact to streets, fire service, schools and city parks per ACC Title 19. PLEASE NOTE: Applicants are responsible for complying with all City Codes and ordinances; and should review all City regulations that may be applicable to their proposed project. For assistance in determining which regulations are applicable, please contact the City of Auburn Permit Center. QUESTIONS? PHONE 253.931.3090 or E-MAIL permitcenter@auburnwa.gov 24 of 628 25 of 628 26 of 628 Form Updated May 2018 5 CITY OF AUBURN PRELIMINARY SUBDIVISION (PLAT) Planning & Development Department APPLICATION Auburn City Hall Annex, 2nd Floor 1 East Main Street / Auburn, WA 98001 Tel: (253) 931-3090 / Fax: (253) 804-3114 permitcenter@auburnwa.gov / www.auburnwa.gov PRELIMINARY SUBDIVISION (PLAT) APPLICATION CONCURRENT APPLICATIONS Please indicate whether you are submitting one or more concurrent applications with this application by checking one or more of the boxes below: Type I Applications (administrative decisions made by the city which are not subject to environmental review under the State Environmental Policy Act [SEPA]): Administrative Use Permit Boundary Line Adjustment Boundary Line Elimination Building Permit Excavation Permit Floodplain Development Permit Grading Permit Home Occupation Permit Land Clearing Permit Mechanical Permit Plumbing Permit Public Facility Extension Agreement Right-of-way Use Permit Short Subdivision Special Permit Temporary Use Permit (administrative) Utility Permit Type II Applications (administrative decisions made by the city which include threshold determinations under SEPA): Administrative Use Permit Building Permit Floodplain Development Permit Grading Permit Land Clearing Permit Public Facility Extension Agreement Short Subdivision Type III Applications (quasi-judicial final decisions made by the hearing examiner following a recommendation by staff: Conditional Use Permit Preliminary Plat Special Exceptions Special Home Occupation Permit Substantial Shoreline Development Permit Surface Mining Permit Temporary Use Permit Variance Type IV Applications – (quasi-judicial decisions made by the city council following a recommendation by the hearing examiner): Rezone (site-specific) OTHERS - as may apply: SEPA_____________ SHORELINE EXEMPT ___________________ ___________________ 27 of 628 28 of 628 Form Updated May 2018 7 CITY OF AUBURN PRELIMINARY SUBDIVISION (PLAT) Planning & Development Department APPLICATION Auburn City Hall Annex, 2nd Floor 1 East Main Street / Auburn, WA 98001 Tel: (253) 931-3090 / Fax: (253) 804-3114 permitcenter@auburnwa.gov / www.auburnwa.gov PRELIMINARY SUBDIVISION (PLAT) APPLICATION SUBMITTAL CHECKLIST DIGITAL COPIES OF WRITTEN MATERIALS AND PLANS & GRAPHICS Please provide a labeled readable compact disc(s) containing digital versions of all submitted written materials and plans and graphics for use by the City of Auburn during the preliminary plat review process. Staff will use this information in report preparation and public noticing so please be sure to provide current and accurate information. Written materials should be submitted to be compatible with Microsoft Office desktop software products. Plans and graphics should be submitted in pdf or tiff format APPLICATION FEES - Make checks payable to the City of Auburn All application fees, including, but not limited to fees for: Preliminary Plats and Public Notice Board Posting. Some fees will not be invoiced until actual costs are known. Fees will be assessed as outlined in the current year’s fee schedule: http://www.auburnwa.gov/forms WRITTEN MATERIALS – Total of ten (10) copies unless otherwise noted A.APPLICATION FORM. Provide a completed application form signed by the property owner(s) and/or applicant with the completed Application Submittal Checklist. (One original and 9 copies) B.LETTER OF AUTHORIZATION. Provide one original letter of authorization to act contained with this application packet inclusive of all required signatures. C.CONCURRENT APPLICATIONS FORM Identify applications that are being submitted concurrent with the subdivision application and concurrent review of a SEPA environmental checklist. D LAND SURVEYOR’S CERTIFICATION Provide one original signed and sealed Land Surveyor’s Certification as contained within this application and completed by a professional land surveyor E.LEGAL DESCRIPTION. Provide on a separate sheet a legal description of the property to be subdivided. The legal description shall be prepared by a professional land surveyor registered in the State of Washington. F.TITLE REPORT (2 Copies) with liability for errors not to exceed the assessed value of the lots on the date of application. The title report shall be issued no more than 30 days prior to the application date (available from a Title Company). The City may request an updated title report prior to preliminary approval at its discretion. G.PRELIMINARY SUBDIVISION APPLICANTION SUBMITTAL CHECKLIST – Addressing Written Materials and Drawings with Plans. 29 of 628 Form Updated May 2018 8 PRELIMINARY SUBDIVISION (PLAT) APPLICATION H. SEPA CHECKLIST. If applicable, submit a completed environmental checklist together with any supporting documentation, such as a critical areas report (see below), or information to address potential or known environmental impacts resulting from the proposal. I. TRAFFIC IMPACT ANALYSIS (6 copies). If the preliminary plat application is for a new use or an expanded use that will generate traffic, safety or other issues, the City Engineer may require submittal of a traffic analysis prepared by a professional engineer licensed in the State of Washington. The City Engineer may make this determination prior to application submittal as part of a pre-application conference meeting request or as part of coordination with the applicant prior to application submittal. Traffic Analysis required and attached. Traffic Analysis is not applicable as determined by the City Engineer Don’t know J. SCHOOL ACCESS ANALYSIS (6 copies). If a residential subdivision is proposed, provide a School Access Analysis to determine the safety of walking conditions for students who walk to and from school (RCW 58.17.110). K. PRELIMINARY STORM REPORT (6 copies). The following Minimum Requirements must be addressed in the preliminary storm report, if applicable to the project, with supporting calculations, justification, and drawings, in accordance with the City of Auburn Surface Water Management Manual (current edition): Minimum Requirement #5 – On-Site Stormwater Management (Low Impact Development [LID]) Minimum Requirement #6 – Runoff Treatment Minimum Requirement #7 – Flow Control Minimum Requirement #8 – Wetlands Protection Minimum Requirement #10 – Off-Site Analysis and Mitigation L. CRITICAL AREAS REPORT (6 copies), if applicable, addressing compliance ACC 16.10 (Critical Areas) prepared by a qualified consultant as defined by ACC 16.10.020 as a person who has attained a degree from an accredited college or university in the subject matter necessary to evaluate the critical area in question (e.g., biology, ecology, or horticulture/arboriculture for wetlands, streams, wildlife habitat, and geology and/or civil engineering for geologic hazards, and hydrogeologist for ground water protection areas), and/or who is professionally trained and/or certified or licensed by the State of Washington to practice in the scientific disciplines necessary to identify, evaluate, manage, and mitigate impacts to the critical area in question. Known or Suspected Critical Area Class Analysis Required Analysis Prepared Wetlands ______ Stream ______ Wildlife Habitat Area ______ Geologic Hazard Area Seismic, steep slope, landslide, & erosion ______ Groundwater Protection Area ______ Other: Flood Hazard - ACC 15.68 ______ 30 of 628 Form Updated May 2018 9 PRELIMINARY SUBDIVISION (PLAT) APPLICATION M. GEOTECHNICAL SOIL ANALYSIS REPORT (6 copies). Prepared by a geotechnical engineer licensed in the State of Washington. At a minimum, the geotechnical report shall include the required information from Volume I, Section 3.1.1.2 of the DOE’s current Stormwater Management Manual for Western Washington and address the following: Soil infiltration rate (inches per hour) Seasonal (Winter) High Groundwater Elevation N. EVIDENCE OF WATER/SEWER AVAILABILITY. If the property is located within the City’s Water and/or Sanitary Sewer Service Area, the city shall confirm the applicability of utilities as part of the preliminary plat review process. If the property is located outside the City’s Water or Sanitary Sewer Service Area, application shall include evidence of water and/or sanitary sewer availability from the purveyor or evidence of approval from King County or Pierce County Health Departments for any well and/or on-site sewage disposal system(s) adequate to accommodate the proposed development. Where any lot is proposed to be served by an on-site sewage disposal system, results of preliminary percolation tests for each such proposed lot, conducted under the applicable county department of health rules and regulations, shall be submitted. Water Service by City Sanitary Sewer by City Water and/or Sewer Service by another agency and Availability Certificate attached. On-site sewage disposal system planned and County Health approval attached. On-site well planned and County approval and well covenant are attached. O. RESTRICTIONS. Provide documents containing applicable restrictions, if any, to be imposed upon the use of the land. Such restrictions must be recorded simultaneously with the subdivision. P. PRE-APPLICATION CONFERENCE SUMMARY NOTES. Provide one (1) copy of the summary notes from the Pre-application Conference (if a pre-application conference meeting was held). Q. NEIGHBORHOOD REVIEW MEETING DOCUMENTATION. Submit required documentation for neighborhood review meeting required by ACC 18.02.130, if applicable. Neighborhood review meetings are required by ACC 18.02.130.B for residential subdivision project comprising forty (40) or more lots or units; or multi-family residential project comprising forty (40) or more units; or mixed- use development project comprising forty (40) or more units. R. WRITTEN/PLAN/GRAPHIC EVIDENCE OF COMPLIANCE TO MULTI-FAMILY/MIXED USE DESIGN STANDARDS AND INFILL STANDARDS. If applicable to the proposed project, submit required written and plan/graphic documentation demonstrating compliance to the applicable design standards for multi-family or mixed use development contained within the City of Auburn “Multi- Family/Mixed Use Developments Design Standards”. If infill standards apply, submit required written and plan/graphic documentation demonstrating compliance with ACC 18.25. 31 of 628 32 of 628 Form Updated May 2018 11 PRELIMINARY SUBDIVISION (PLAT) APPLICATION C. PRELIMINARY PLAT DRAWING - GRAPHIC REPRESENTATION The Preliminary Plat Drawing must be prepared by a professional land surveyor licensed in the State of Washington and the following graphic features shall be shown on the drawing: 1. Indicate boundaries of the subdivision by a heavy line. Use heavier line weight for streets so they will stand out from the lots and contour lines. 2. The boundaries and approximate dimensions of all proposed lots and tracts to the nearest foot, Include the square footage of each. Identify all lots proposed to be created by lot number and tracts by alphabetic identification, together with the purpose of the tract. Also include the location, width, and purpose of each new easement to be created. 3. Location, widths, and names of all existing or proposed streets, public ways, or private streets within or adjacent to the plat. (City will assign street names after initial review of application and plat) 4. Location of storm water quality/detention facilities, existing vegetation and infiltrative soils areas to be preserved, and natural drainage features. 5 Location of Critical Areas, and Critical Area Buffers. 6 Location of public and private parks, and open space areas 7. A section or quarter section breakdown with appropriate ties to the subject parcel(s). 8. The boundaries of any adjacent property under the same ownership as the land to be subdivided. 9. All existing property lines lying within the proposed subdivision which are to be vacated. 10. Where the property has been previously subdivided, the original lots, blocks, street easements, etc., shall be shown in dotted lines in scale with the proposed subdivision. 11. Identify setbacks from proposed property lines and easements for existing structures to remain. 12. Show location of all physical and legal description encroachments affecting the boundary between the application site and the adjoining parcels. Encroachments may be from the application site onto the adjoining parcels or from the adjoining parcels onto the application site. D. EXISTING FEATURES PLAN / FIELD TOPOGRAPHY Provide a plan be prepared by a professional land surveyor licensed with the State of Washington showing the following: 1. Existing topography of the land indicated with contours at 2-foot intervals when slopes are 5% or less and 5-foot intervals for slopes exceeding 5% within the boundaries of the proposal. Identify all slopes 25 percent or greater on or within 25 feet of the site. Contours for streets abutting the property must also be included. Contour lines shall be labeled at intervals not to exceed twenty (20) feet, and shall be based upon current City Datum in accordance with the City’s Engineering Design Standards. 2. Location of existing vegetation on site, specifically identifying “Significant Trees” defined as healthy evergreen tree, six inches or more in diameter measured four feet above grade, or a healthy deciduous tree four inches or more in diameter measured four feet above grade (ACC 15.74.030N.). 3. Show location and extent of all critical areas; shorelines of the state; FEMA flood designations; hydrologic features within 200 feet of the boundaries to the site; and required buffers and/or setbacks. Indicate if streams are intermittent and the limits of any wetlands. Identify the limits of the 25-year floodplain for streams and 100-year floodplain for rivers. Provide names of all water features and all drainage basins served 33 of 628 Form Updated May 2018 12 by or containing these features. Contours for these features must be sufficient to accurately determine the existing character. 4. Show all existing structures, including rockeries fences and walls; and parcels both within the proposed subdivision and within 100 feet of the boundaries of the proposed subdivision. Indicate whether or not the on-site structures will be removed or relocated. 5. The location, widths, and purposes of any existing easements including recording numbers, lying within the proposed subdivision; and any known adjacent easements. 6. Show the location of existing utilities on the property and within adjacent right-of-way. E. CONCEPTUAL GRADING PLAN. Provide a conceptual grading plan prepared by a professional engineer licensed in the State of Washington, showing: 1. Existing and proposed grades with cross sections to demonstrate code compliance. 2. Location of proposed clearing and grading limits. 3. Contour lines at 2-foot intervals when slopes are 5% or less and 5-foot intervals for slopes exceeding 5% within the boundaries of the proposal. Contour lines shall be labeled at intervals not to exceed twenty (20) feet, and shall be based upon current City Datum in accordance with the City’s Engineering Design Standards. Existing contour lines which will be altered through filling or excavation shall be indicated by broken lines (final contour lines shall be indicated by solid lines). 4. The conceptual grading/clearing plan must identify grading required on site and within proposed or existing right-of-way. 5. Contours for critical area features must be sufficient to accurately determine the existing character and extent of proposed change. F. CONCEPTUAL UTILITY PLAN - Water, Sewer, Storm and Other Provide a conceptual utility plan prepared by a professional engineer licensed in the State of Washington showing all utility infrastructure needed to serve the subdivision and/or methodology prepared in accordance with the City’s comprehensive plans, engineering standards or ordinance requirements. The conceptual utility plan shall include information to ensure that utilities can be constructed consistent with the preliminary plat layout and that the facilities will ultimately meet City design requirements including adequate maintenance and repair access. The Plan shall specify the following information: 1. Background grading contours and adequate horizontal and vertical datum. 2. The location of all existing and proposed ditches, culverts, catch basins, and other parts of the design for the control and conveyance of surface water drainage; and existing and proposed water quality facilities. 3. The location of tracts or easements (or other areas) dedicated for retention , detention, and drainage facilities. 4. The location and size of existing sanitary sewer, storm sewer, and water lines or other utilities lying within or adjacent to the proposed subdivision. 5. The location, size and vertical profile for all proposed sanitary sewer, storm sewer, and water lines or other utilities to serve the proposed subdivision. 6. The location of any well used for domestic water supply existing within the proposed subdivision or within one hundred (100) feet of the boundaries of the proposed subdivision. 7. The location of other utilities other than those provided by the City. 8. If electrical transmission lines cross the subject property, show locations of poles and towers. Identify overhead electrical, and other facilities that are required to be undergrounded. 9. Place all regional utility lines crossing the site in tract(s) or easements. 10. Identify any non City facilities, such as: booster stations, PVR’s, wells, or lift stations proposed to serve the proposed subdivision. 34 of 628 Form Updated May 2018 13 PRELIMINARY SUBDIVISION (PLAT) APPLICATION G. TRANSPORTATION PLAN - Neighborhood Circulation, Conceptual Street, and Access 1. Planned street system. The planned street system must be compatible with the City’s Comprehensive Transportation Plan. Development which is proposed in areas of the city which have a planned street system which is a part of the comprehensive plan or the city’s six (6) year plan, and any other street plan, shall make provisions for such streets and must not preclude implementation of such street plans. 2. Provide a conceptual street and access plan prepared by a professional engineer licensed in the State of Washington. The plans shall show existing and proposed streets, access points and access points adjacent or on the opposite side of the subject property’s frontage. The application shall also include a transportation site plan for streets, pedestrian, and bike facilities. The site plan shall include adequate horizontal and vertical information to ensure the transportation facilities can be constructed consistent with the preliminary plat layout. The plan should show: a. The location, right-of-way widths, pavement widths, classifications and names of all existing or platted streets, whether public or private, and other public ways including railroads right of way within or adjacent to the proposed subdivision. b. The boundaries and approximately dimensions of all proposed streets to the nearest foot. c. Adequate horizontal and vertical street geometrics to ensure compliance with City Standards for all proposed streets. Including plan and profile drawings of all proposed streets. d. Sight distance triangles for entry to all streets and at all intersections (private and public). e. Typical roadway sections, including streetlights and street trees for all proposed streets and existing frontage streets. 3. Non-motorized transportation routes. Preliminary plats and binding site plans which are proposed in areas of the city which have planned routes or facilities for bicycles, equestrian, or other non-motorized transportation mode which is a part of the comprehensive plan or the city’s six (6) year plan, and any other street plan, shall make provisions for such routes and must not preclude implementation of such routes. 4. A non-motorized circulation system shall be integrated into the overall subdivision and surrounding area as follows: a. When abutting vacant or underdeveloped land, new developments shall provide for the opportunity for future connection to its interior pathway system through the use of pathway stub-outs, building configuration, and/or parking lot layout. The proposed location of future non-motorized and pedestrian connections shall be reviewed in conjunction with applicable development approval. b. Developments shall include an integrated non-motorized circulation system that connects buildings, open spaces, and parking areas with the adjacent street sidewalk system. c. Pedestrian connections to existing or proposed trails/pedestrian routes on adjacent properties shall be provided unless there are physical constraints such as critical areas that preclude the construction of a pedestrian connection. d. Show walking conditions and planned improvements for students who only walk to and from school for a residential subdivision (RCW 58.17.110). 35 of 628 Form Updated May 2018 14 PRELIMINARY SUBDIVISION (PLAT) APPLICATION H. LANDSCAPE PLAN The Landscape Plan shall be prepared by a professional landscape architect licensed in the State of Washington showing existing wooded areas, meadows, rock outcroppings, proposed and required buffers, open spaces, street trees, significant trees, ornamental landscaping, and other landscape features. The Plan shall identify areas to be cleared and those significant trees to be retained and those to be removed. This plan needs to include background information, including: sight distance triangles, proposed utilities, driveway access, and street lighting to show that all required improvements can be met by the proposed subdivision. I. PHASING PLAN If applicable show divisions of the plat and a proposed timetable for construction of each division. Including the phasing of the public improvements required to serve each phase of the project and how each phase will individually meet City standards and requirements. (i.e. may need to extend utility improvements beyond phase lines to complete looping or to reach appropriate terminus points of the utility systems.) DECISION CRITERIA FOR SUBDIVISIONS The following State and City Codes comprise the main factors to be considered in review of a subdivision application. To assess compliance of the subdivision with these codes, the City relies on policies, codes, special studies, SEPA and other applicable documentation. This list does not include all possible applicable codes. RCW 58.17.110 - Approval or disapproval of subdivision and dedication — Factors to be considered Conditions for approval — Finding — Release from damages (1) The city, town, or county legislative body shall inquire into the public use and interest proposed to be served by the establishment of the subdivision and dedication. It shall determine: (a) If appropriate provisions are made for, but not limited to, the public health, safety, and general welfare, for open spaces, drainage ways, streets or roads, alleys, other public ways, transit stops, potable water supplies, sanitary wastes, parks and recreation, playgrounds, schools and school grounds, and shall consider all other relevant facts, including sidewalks and other planning features that assure safe walking conditions for students who only walk to and from school; and (b) whether the public interest will be served by the subdivision and dedication. (2) A proposed subdivision and dedication shall not be approved unless the city, town, or county legislative body makes written findings that: (a) Appropriate provisions are made for the public health, safety, and general welfare and for such open spaces, drainage ways, streets or roads, alleys, other public ways, transit stops, potable water supplies, sanitary wastes, parks and recreation, playgrounds, schools and school grounds and all other relevant facts, including sidewalks and other planning features that assure safe walking conditions for students who only walk to and from school; and (b) the public use and interest will be served by the platting of such subdivision and dedication. If it finds that the proposed subdivision and dedication make such appropriate provisions and that the public use and interest will be served, then the legislative body shall approve the proposed subdivision and dedication. Dedication of land to any public body, provision of public improvements to serve the subdivision, and/or impact fees imposed under RCW 82.02.050 through 82.02.090 may be required as a condition of subdivision approval. Dedications shall be clearly shown on the final plat. No dedication, provision of public improvements, or impact fees imposed under RCW 82.02.050 through 82.02.090 shall be allowed that constitutes an unconstitutional taking of private property. The legislative body shall not as a condition to the approval of any subdivision require a release from damages to be procured from other property owners. 36 of 628 Form Updated May 2018 15 PRELIMINARY SUBDIVISION (PLAT) APPLICATION RCW 58.17.120 - Disapproval due to flood, inundation or swamp conditions — Improvements — Approval conditions The city, town, or county legislative body shall consider the physical characteristics of a proposed subdivision site and may disapprove a proposed plat because of flood, inundation, or swamp conditions. Construction of protective improvements may be required as a condition of approval, and such improvements shall be noted on the final plat. No plat shall be approved by any city, town, or county legislative authority covering any land situated in a flood control zone as provided in chapter 86.16 RCW without the prior written approval of the department of ecology of the state of Washington. AUBURN CITY CODE – ACC 17.10.070 - Findings of Fact: Preliminary plats shall only be approved if findings of fact are drawn to support the following: A. Adequate provisions are made for the public health, safety and general welfare and for open spaces, drainage ways, streets, alleys, other public ways, water supplies, sanitary wastes, parks, playgrounds and for schools; B. Conformance of the proposed subdivision to the general purposes of the comprehensive plan; C. Conformance of the proposed subdivision to the general purposes of any other applicable policies or plans which have been adopted by the city council; D. Conformance of the proposed subdivision to the general purposes of this title, as enumerated in ACC 17.02.030; E. Conformance of the proposed subdivision to the Auburn zoning ordinance and any other applicable planning or engineering standards and specifications as adopted by the city, or as modified and approved as part of a previously approved PUD ; F. The potential environmental impacts of the proposed subdivision are mitigated such that the preliminary plat will not have an unacceptable adverse effect upon the quality of the environment; and, G. Adequate provisions are made so the preliminary plat will prevent or abate public nuisances. 37 of 628 NOTICE OF APPLICATION (NOA) and DETERMINATION OF NON-SIGNIFICANCE (DNS) CARBON TRAILS 44-LOT PRELIMINARY PLAT SEP19-0003 The City of Auburn is issuing a Notice of Application (NOA) and Determination of Non-Significance (DNS) for the following described project. The permit applications and listed studies may be reviewed at the Auburn Department of Community Development at One E Main St., 2nd Floor, Customer Service Center, Auburn, WA 98001. Proposal: Preliminary Plat of Carbon Trails, a 44-lot subdivision for the future construction of 44 single- family residences. An existing single-family residence will be removed as part of the proposal. The project involves 35,000 cubic yards of cut and fill, public street improvements, and other associated site development activities that will support the creation of 44 single-family residential home sites. Location: The site is located west of 56th Ave S and east of 51st Ave S along S 328th Street, King County Parcel Numbers 9262800295, 9262800320, and 9262800313. Notice of Application: October 15, 2021 Application Complete: March 1, 2019 Permit Application: January 18, 2019 File Nos. SEP19-0003 PLT19-0002 DEV21-0035 DEV21-0036 Applicant: Jason Hubbell, P.E. Barghausen Consulting Engineers, Inc. 18215 72nd Ave S Kent, WA 98032 Property Owner: Stowe Investments, LLC P.O. Box 1054 Sumner, WA 98390 Studies/Plans Submitted With Application: • Preliminary Plat Plan and Civil Drawings, prepared by Barghausen Consulting Engineers, Inc., dated September 10, 2021 • Preliminary Stormwater Site Plan, prepared by Barghausen Consulting Engineers, Inc., dated April 30, 2021 • Traffic Impact Analysis, prepared by TENW, dated July 1, 2021 • Critical Area Report, prepared by Sewall Wetland Consulting, Inc., dated January 14, 2019 • Geotechnical Report, prepared by GeoResources, dated January 14, 2019 Other Permits, Plans, and Approvals Needed: • Preliminary Plat, Final Plat, Facility Extension Agreement (FAC), Grading Permit, Demolition Permit(s), Building Permit(s) Statement of Consistency and List of Applicable Development Regulations: This proposal is subject to and shall be consistent with the Auburn City Code, Comprehensive Plan, and Public Works Design and Construction Standards. 38 of 628 NOTICE OF APPLICATION and DETERMINATION OF NON-SIGNIFICANCE SEP19-0003 (Continued) Page 2 of 4 Lead Agency: City of Auburn The lead agency for this proposal has determined that it does not have probable significant adverse impact on the environment. An environmental impact statement (EIS) is not requir ed under RCW 43.21C.030(2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. This information is available to the public on request. Public Comment Period: This may be your only opportunity to comment on the environmental impact of the proposal. All persons may comment on this application. This DNS is issued under WAC 197-11-355; the lead agency will not act on this proposal for 15 days from the date issued below. Comments must be in writing and submitted by 5:00 pm on November 1, 2021 to the mailing address of 25 W Main ST, Auburn, WA, 98001 or emailed to the contact below. Any person wishing to become a party of record, shall include in their comments that they wish to receive notice of and participate in any hearings, if relevant, and request a copy of decisions once made. Any person aggrieved of the City's determination may file an appeal with the Auburn City Clerk at 25 West Main Street, Auburn, WA 98001- 4998 within 14 days of the close of the comment period, or by 5:00 p.m. on November 15, 2021. For questions regarding this project, please contact Dustin Lawrence, AICP, CFM, Senior Planner, at planning@auburnwa.gov or 253-931-3092. Public Hearing: The Public Hearing will be scheduled at a later time. RESPONSIBLE OFFICIAL: Jeff Tate POSITION/TITLE: Director, Department of Community Development ADDRESS: 25 West Main Street Auburn, Washington 98001 253-931-3090 DATE ISSUED: SIGNATURE: Note: This determination does not constitute approval of the proposal. Approval of the proposal can only be made by the legislative or administrative body vested with that authority. The proposal is required to meet all applicable regulations. October 15, 2021 39 of 628 NOTICE OF APPLICATION and DETERMINATION OF NON-SIGNIFICANCE SEP19-0003 (Continued) Page 3 of 4 Project Site 40 of 628 NOTICE OF APPLICATION and DETERMINATION OF NON-SIGNIFICANCE SEP19-0003 (Continued) Page 4 of 4 Proposed Site Plan (Draft) 41 of 628 FINAL STAFF EVALUATION FOR ENVIRONMENTAL CHECKLIST (SEP19-0003) Date: October 11, 2021 Project: Carbon Trails 44-Lot Preliminary Plat Applicant: Jason Hubbell, Project Engineer Barghausen Consulting Engineers, Inc. 18215 72nd Avenue S Kent, WA 98032 Property Owner(s) Stowe Investments, LLC PO Box 1054 Sumner, WA 98390-0200 Location: The site is located west of 56th Ave S and east of 51st Ave S along S 328th Street. Parcel No. King Co. Parcel No. 9262800295, 9262800320, and 9262800313 Project Size: 495,210 sq. ft. / 11.37 acres Proposal: Preliminary Plat of Carbon Trails, a 44-lot subdivision for the future construction of 44 single-family residences. An existing single-family residence will be removed as part of the proposal. The project involves 35,000 cubic yards of cut and fill, public street improvements, and other associated site development activities that will support the creation of 44 single-family residential home sites. Existing Zoning: R-5 Residential Zone – 5 Dwelling Units per Acre and West Hill Overlay Existing Comprehensive Plan Designation: Single-Family A. BACKGROUND: Pursuant to WAC 197-11-355, the City of Auburn is required to send any Determination of Non-Significance (DNS) which may result from this environmental review, along with the checklist, to agencies with jurisdiction, the Washington State Department of Ecology (ECY), affected tribes, and each local agency or political subdivision whose public services would be changed as a result of implementation of the proposal. Therefore, the City will not act on this proposal for fifteen days after the issuance of the DNS. 1. Other Environmental Information: 42 of 628 Final Staff Evaluation for Environmental Checklist – SEP19-0003 (Continued) Page 2 of 4 • Preliminary Plat Plan and Civil Drawings, prepared by Barghausen Consulting Engineers, Inc., dated September 10, 2021 • Preliminary Stormwater Site Plan, prepared by Barghausen Consulting Engineers, Inc., dated April 30, 2021 • Traffic Impact Analysis, prepared by TENW, dated July 1, 2 021 • Critical Area Report, prepared by Sewall Wetland Consulting, Inc., dated January 14, 2019 • Geotechnical Report, prepared by GeoResources, dated January 14, 2019 2. Other Approvals/Permits Needed: • Demolition Permit • Grading Permit • Facility Extension Agreement (FAC) • Preliminary Plat • Final Plat • Building Permit B. ENVIRONMENTAL ELEMENTS: 1. Earth: Concur with checklist, with the following comments: The site slopes from north to south, with some slopes being up to 40%. City records indicate that the site does not contain any erosion prone or landslide hazard areas. The applicant provided a geotechnical report confirming that there are no geological hazardous areas on the site, as defined in ACC 16.10. Further, the geotechnical report provided recommendations related to the future development of the site to ensure no long term geologic or slope stability related impacts occur as a result of the project. 2. Air: Concur with checklist. Short term impacts on air quality, such as an increase in local suspended particulate levels, would occur during any future construction activity associated with the project. To minimize short term impacts to air quality, contract specifications will require the development and implementation of dust and emission control measures such as watering and sweeping and turning off equipment and vehicles when not in use, as consistent with the City’s Construction Standards. 3. Water: A. Surface: Concur with checklist. The project will not result in any impacts to surface water. There is a Category III wetland located on the north portion of the project site with a required buffer of 50-feet. No impacts are proposed to the wetland or buffer. According to the Stormwater Site Plan, the backyard areas of Lots 1-6 and 17 will provide hydrology to the wetland through the addition of a French drain. Provided that hydrology is maintained, the project will not result in any impacts to the known Category III wetland on the site. B. Ground: Concur with checklist. C. Runoff/Storm water: Concur with checklist. 43 of 628 Final Staff Evaluation for Environmental Checklist – SEP19-0003 (Continued) Page 3 of 4 D. Proposed Measures to Reduce or Control Surface, Ground, and Runoff Water Impacts: Concur with checklist, with the following comment: Best Management Practices (BMPs) will be employed during and after construction to control any impacts to ground/surface/storm water. The project is located within the critical area known as Ground Water Protection Zone 4, which will require the implementation of best management practices for water resource protection per ACC 16.10.120(E). 4. Plants: Concur with checklist. Native vegetation within the existing wetland and buffer area will remain undisturbed. 5. Animals: Concur with checklist. 6. Energy and Natural Resources: Concur with checklist. No Impacts to energy and natural resources would occur as part of the proposal. Any future construction will need to comply with applicable building and energy codes. 7. Environmental Health: Concur with checklist. No environmental health hazards above normal construction activities are expected and risk reduction measures consistent with the City’s Construction Standards will be implemented and followed. 8. Noise: Concur with checklist. Any noise impacts that could potentially result from the proposal will be reviewed as part of any future building, grading, or construction permit review. Future development must adhere to ACC Chapter 8.28 and 18.31. 9. Land and Shoreline Use: Concur with checklist. The site is currently zoned R-5 Residential Zone, Five Dwelling Units per Acre and West Hill Overlay, with a Single Family Comprehensive Plan designation. 10. Housing: Concur with checklist. The site is currently developed with one single-family residence, which is proposed to be removed. While one existing housing unit will be lost, the project will result in the creation of 44 single-family residential home sites. As such, no long term impacts to housing will occur. 11. Aesthetics: Concur with checklist. Any impacts related to aesthetics will be reviewed and analyzed as part of the future building, grading, and construction permits for the site. 12. Light and Glare: Concur with checklist. 44 of 628 Final Staff Evaluation for Environmental Checklist – SEP19-0003 (Continued) Page 4 of 4 Any impacts related to light and glare will be reviewed and analyzed as part of the future building, grading, and construction permits for the site and will need to meet the requirements of ACC 18.31.180. 13. Recreation: Concur with checklist. No existing recreation facilities will be impacted as part of the proposal. Park impact fees will be required on a per residential lot basis, ensuring that adequate recreation facilities are provided to serve the project. 14. Historic and Cultural Preservation: Concur with checklist, with the following comment: The Washington Department of Archaeology and Historic Preservation WISAARD mapping tool notes that this is a low-risk area to contain cultural significant sites and as such, a cultural resources study isn’t necessary. 15. Transportation: Concur with checklist. The project will result in the construction of 44 single-family residences, resulting in a total net increase of 480 new weekday daily trips, as outlined in the Traffic Impact Analysis. To mitigate for the impacts created from the increase in vehicle trips, the applicant will pay the required traffic impact fees as part of each future building permit for each newly constructed residence. The impact fee money collected will be used to support future transportation improvement projects near the project site. Additionally, the applicant will be improving the S 328th St right-of-way with a new public road with curb, gutter, and sidewalk. 16. Public Services: Concur with checklist. Public services will be able to serve the site. No significant impacts to public services, such as police, fire, EMS, and public transit were identified as part of the proposal. 17. Utilities: Concur with checklist. All necessary utilities will be provided to the project site and system engineers have determined there is adequate water, sewer, and storm after reviewing utility plans for the area. C. CONCLUSIONS: The proposal can be found to not have a probable significant adverse impact on the environment. The City reserves the right to review any future revision or alterations to the site or to the proposal in order to determine the environmental significance or non-significance of the project at that point in time. Prepared by: Dustin Lawrence, AICP, CFM, Department of Community Development, City of Auburn 45 of 628 ENVIRONMENTAL CHECKLIST 18355.002.doc Page 1 of 12 CITY OF AUBURN SEPA ENVIRONMENTAL CHECKLIST Planning & Development Department Auburn City Hall Annex, 2nd Floor 1 East Main Street Auburn, Washington 98001-4998 Tel: 253.931.3090 Fax: 253.804.3114 permitcenter@auburnwa.gov www.auburnwa.gov SEPA ENVIRONMENTAL CHECKLIST 1. Name of proposed project, if applicable: Carbon Trails 2. Name of Applicant: Bryan Stowe, Stowe Investments LLC 3. Address and phone number of applicant and contact person: A. Applicant: Agent (if applicable) Stowe Investments LLC Barghausen Consulting Engineers, Inc. PO Box 1054 18215 72nd Avenue South Sumner, WA 98390-0200 Kent, WA 98032 (253) 606-8741 (425) 251-6222 4. Date checklist prepared: January 17, 2019, Revised April 30, 2021 5. Agency requesting checklist: City of Auburn 6. Proposed timing or schedule (including phasing, if applicable): Clearing and Grading Spring 2022 Road and Utility Construction Summer –Fall 2022 Home Construction Fall 2022-Fall 2024 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. No future additions are known at this time. 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. 46 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 2 of 12 A Critical Area Report has been prepared by Sewall Wetland Consulting, Inc. dated January 14, 2019. 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. There are no known other applications pending for governmental approvals directly affecting this property. 10. List any government approvals or permits that will be needed for your proposal, if known. Department of Ecology Construction Stormwater General Permit City of Auburn Facility Extension Permit Grading Permit Demolition Permit Building Permits Plumbing & Mechanical Permits Lakehaven Water and Sewer District – Water and Sewer Extension Level 3 Storm Permit 11. Give a brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. The proposed project is to develop three parcels in Auburn for a single-family residential plat. The three parcels are approximately 11.4 acres combined. There is currently a single-family residence on the northern parcel that will be removed with this development. The southern parcels are vacant. Besides the two buildings, the remainder of the sites are covered in trees and brush. There is a known noxious weed issue with Tansy Ragwort. There are no known sensitive areas, streams or wetlands on this site. This site is designated as drainage for a landslide hazard area. There is no FEMA mapped floodplain on this site. The proposal is to create approximately 44 single-family lots for development. The project would include platting, road improvements, utility extensions, storm drainage conveyance, water quality and detention to meet the City of Auburn requirements. The residential plat would meet the current R-5 zoning, including minimum lot sizes, setbacks and impervious surface coverage. The proposed single-family homes would likely be in the 2500-3500 square foot range with fenced yards and appropriate landscaping and street trees. 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this check list. The site is located both north and south of S. 328th Street, west of 56th Avenue South in Auburn, Washington. The site is in a portion of Section 14, Township 21 North, Range 4 East in King County. 47 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 3 of 12 ENVIRONMENTAL ELEMENTS 1. Earth A. General description of the site (check one): Flat, rolling, hilly, steep slopes, mountainous, other. The site has steep slopes and has a rolling topography. The site slopes from north to south. B. What is the steepest slope on the site (approximate percent slope)? The steepest slopes are approximately 30-40 percent. C. What general types of soils are found on the site (for example, clay, sand, gravel, peat, muck)? If you know the classification of agricultural soils, specify them and note any prime farmland. The onsite soils are Alderwood gravelly, sandy loam. They are hydrologic group ‘C’ soils. The geotechnical report identified 1-8.5 feet of topsoil/fill with organics and construction debris during their site exploration. Below the topsoil/fill was damp sandy silt w ith oxide staining and silty sand with gravel below the silt. The geotechnical investigation confirmed the till soils. D. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. No. There is a landslide hazard area to the south, adjacent to SR-18 depicted on King County iMap. E. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. There will be approximately 35,000 cubic yards of cut and fill on the site and 28,000 cubic yards of export to prepare the site the buildable lots. No fill is anticipated to be required for the site. F. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. Yes, erosion could occur as a result of clearing and construction. However, the implementation of a temporary sediment and erosion control plan using Best Management Practices should mitigate impacts. G. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? It is anticipated that approximately 65 percent of the site will be covered with impervious surfaces after the construction of the residences and associated driveways. H. Proposed measures to reduce or control erosion, or other impacts to the earth. The proposal will follow the City of Auburn development standards, including developing a temporary erosion and sedimentation control plan for the site to minimize erosion potential. 2. Air A. What types of emissions to the air would result from the proposal (i.e., dust, automobile, odors, industrial wood smoke) during construction and when the project is competed? If any, generally describe and give approximate quantities if known. 48 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 4 of 12 Construction activities at the site will stir up dust particles. Construction vehicles and equipment will also be a potential source of exhaust emissions. After project completion, the primary sources of emissions will be automobile exhaust from residents. B. Are there any off-site sources of emissions or odors that may affect your proposal? If so, generally describe. There are no off-site sources of emissions or odor that would affect the project. C. Proposed measures to reduce or control emissions or other impacts to air, if any: Watering the ground as needed before and during clearing and grading activities will control dust particles. Vehicles that are not being used in construction activities will be shut off. 3. Water A. Surface 1) Is there any surface water body on or in the immediate vicinity of the site (including year round and seasonal streams, saltwater, lakes, ponds, wetlands): If yes, describe type and provide names. If appropriate, state what stream or river it flows into. There is a wetland at the north edge of the property. Drainage from that wetland flows south through the site. Drainage from this site eventually flows south to the existing ravine just north of SR-18 and into Mill Creek. 2) Will the project require any work over, in, or adjacent to (wit hin 200 feet) the described waters? If yes, please describe and attach available plans. Work will occur within 200 feet of the existing wetland. The proposed wetland buffer is 50 feet. Outside of the 50 foot buffer there will be grading and construction activities for proposed homes, utilities and the proposed access tracts. The proposed preliminary plat plans are included in this SEPA submittal. 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. No filling or excavating will occur within any surface waters. A 50 foot buffer from the wetland will also be maintained. 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. No. 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan. No. 6) Does the proposal involve any disc harges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No. 49 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 5 of 12 B. Ground 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. Groundwater will be encountered during utility excavations and therefore dewatering will be done onsite. Some minor infiltration into the ground will also occur onsite. 2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: domestic sewage; industrial, containing any toxic chemicals; agricultural; etc.). Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) is (are) expected to serve. An existing septic tank on site will be removed with this development. It is anticipated that no waste material will be discharged into the groundwater from septic tanks or other sources since this site will be served by public sewer and water systems. C. Water Runoff (including storm water) 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. Stormwater runoff will be from the proposed building roof s, yards, driveways and streets. Runoff will be collected in catch basins and underground conveyance pipes and routed to the proposed detention and water quality pond prior to being discharged west to 51st Avenue South and then south and east within City right-of-way to the existing downstream discharge point at the ravine north of SR-18. 2) Could waste materials enter ground or surface waters? If so, generally describe. Surface water could be contaminated by runoff containing oil and gasoline from parked cars and streets adjacent to the site. However, surface water runoff will be directed to the water q uality facility prior to its release from the site to the downstream drainage course to minimize surface water contamination. D. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: The new stormwater management system will consist of a detention pond over a water quality pond. The pond will release stormwater through a flow control device to reduce stormwater impacts downstream. 4. Plants A. Check or circle types of vegetation found on the site: Deciduous Tree: Alder, Maple, Aspen; Other Evergreen Tree: Fir, Cedar, Pine, Other Shrubs Grass Pasture Crop or Grain Wet Soil Plants: Cattail, Buttercup, Bullrush, Skunk Cabbage, Other Water Plants: Water Lily, Eelgrass, Milfoil, Other Other Types Of Vegetation 50 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 6 of 12 B. What kind and amount of vegetation will be removed or altered? Most of the site will be grubbed and graded. The dominant vegetation on the site are evergreen trees. There is grass and landscaping trees and shrubs located near the existing home that will also be removed. Existing trees and vegetation within the existing wetland and wetland buffer will be retained. C. List threatened or endangered plant species known to be on or near the site. There are no known threatened or endangered species on or near the site. D. Proposed landscaping, use of native plants, or other measures to preserve or enhance v egetation on the site, if any: The proposal includes the planting of native plants, trees, and low shrubs in landscaped areas and planting street trees to meet City of Auburn standards. The native vegetation in the wetland and wetland buffer will be retained. 5. Animals A. Check any birds and/or animals that have been observed on or near the site or are known to be on or near the site: Birds: hawk, heron, eagle, songbirds, other: geese, ducks, crows, etc. Mammals: deer, bear, elk, beaver, other: Fish: bass, salmon, trout, herring, shellfish, other: B. List any threatened or endangered species known to be on or near the site. There are no known threatened or endangered species on or near the site. C. Is the site part of a migration route? If so, explain. Yes. Various birds are known to migrate through this area. D. Proposed measures to preserve or enhance wildlife, if any: A 50-foot wetland buffer is proposed adjacent to the on-site wetland. Landscaping will be provided on site. 6. Energy and Natural Resources A. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. Electricity and natural gas will be used for home energy needs and street lighting. B. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. It is not anticipated that this project will affect the potential use of solar energy by adjacent properties. C. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: 51 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 7 of 12 The homes will be designed in accordance with the Washington State Energy Code. 7. Environmental Health A. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste that could occur as a result of this proposal? If so, describe. It is anticipated that construction related to this proposal will generate only routine potential for environmental hazards associated with construction such as vehicle fueling and exhaust emissions and exposure to common building products such as paint and adhesives. Best Management Practices will be employed throughout construction to mitigate these risks. 1) Describe special emergency services that might be required: There are no special emergency services anticipated for this project. 2) Proposed measures to reduce or control environmental health hazards, if any: Best Management Practices will be employed throughout construction to mitigate risk of environmental health hazards. 8. Noise A. What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? No noise is known to exist that may affect this project. B. What types and levels of noise would be created by or associated with the project on a short -term or a long- term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. In the short term, there will be general site development and building construction noise. After development, noise will be from single-family homes (music, lawn mowers, air conditioners, etc) and the vehicles going to and from the homes. C. Proposed measures to reduce or control noise impact, if any: The project will comply with the City of Auburn's Noise Control Regulations (AMC -8.28). 9. Land and Shoreline Use A. What is the current use of the site and adjacent properties? The current site contains an existing single-family home with a detached garage and is mostly covered by trees. B. Has the site been used for agriculture? If so, describe: No. C. Describe any structures on the site: There is a single-family home and a detached garage. 52 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 8 of 12 D. Will any structures be demolished? If so, what? Yes, all existing structures will be demolished. E. What is the current zoning classification of the site? The current zoning is R-5 residential. F. What is the current comprehensive plan designation of the site? Single-Family G. If applicable, what is the current shoreline master program designation of the site? Not applicable H. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify: Yes, there is a wetland along the north property line. I. Approximately how many people would reside or work in the completed project? Approximately 110 people will live in the development. J. Approximately how many people would the completed project displace? One family will be displaced by the project. K. Proposed measures to avoid or reduce displacement impacts, if any: None are proposed. L. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: The project is consistent with zoning for the City of Auburn. In addition, this project is in compliance with all applicable federal, state and county standards applicable to this site. HOUSING A. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. The proposed project will include 44 middle income single-family homes. B. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low-income housing. One middle income home is being demolished. C. Proposed measures to reduce or control housing impacts, if any: No housing impacts are anticipated. 53 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 9 of 12 AESTHETICS A. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? Homes will likely be two-story or approximately 30 feet. B. What views in the immediate vicinity would be altered or obstructed? The existing trees will be removed and single-family homes constructed so views will be altered with the development but not obstructed. C. Proposed measures to reduce or control aesthetic impacts, if any: Landscaping around the pond and homes will be provided as well as street trees mitigate the aesthetic impact from the project. LIGHT AND GLARE 1. What type of light or glare will the proposal produce? What time of day would it mainly occur? The roadways will have lights with downward directed fixtures to reduce glare beyond the perimeter of the project site. Homes will have some security lighting. Lights will be during the night. 2. Could light or glare from the finished project be a safety hazard or interfere with views? The area is mainly rural without a lot of street lights. Adding street lighting may impact adjacent pr operties by adding a source of light where there is currently no lighting. 3. What existing off-site sources of light or glare may affect your proposal? None are known. 4. Proposed measures to reduce or control light and glare impacts, if any: Street lights will be directed downward and will provide illumination as required by City of Auburn street standards. RECREATION 1. What designated and informal recreational opportunities are in the immediate vicinity? The existing site is wooded and it appears there are some trails through the site used by neighbors. 2. Would the proposed project displace any existing recreational uses? If so, describe. Yes, the existing wooded area and trails will be removed. 3. Proposed measures to reduce or control impacts on recr eation, including recreation, including recreation opportunities to be provided by the project or applicant, if any: No formal recreation opportunities are proposed. Sidewalks will be provided on both sides of the street to allow for walking or jogging opportunities. 54 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 10 of 12 HISTORIC AND CULTURAL PRESERVATION 1. Are there any places or objects listed on, or proposed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe: No. 2. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. None are known. 3. Proposed measures to reduce or control impacts, if any: No measures are proposed. TRANSPORTATION 1. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. A vicinity map is shown on the plans. The site is between 51 st Avenue S and 56th Avenue South, north of S 331st and south of S. 316th. The site is between I-5 and SR-167, just north of SR-18. Access to SR-167 from the site is north on 56th Avenue South and then east on S 316th Street which turns into 15th Street northwest. Access to SR-18 from the site is south on 56th Avenue South, east on S 331st Street/Mountain View Drive SW and then south on West Valley Highway to SR-18. Heading west on SR-18 will connect to I-5. 2. Is site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? No. The closest transit stops are West Valley Highway and 15 th Street NW, approximately 2 miles from the site or Military Road and S 320th, approximately 1.2 miles from the site. 3. How many parking spaces would the completed project have? How many would the project eliminate? Approximately 88 parking spaces (driveways) would be provided as well as some limited on street parking and approximately 4 spaces would be eliminated. 4. Will the proposal require any new roads or streets, or improvements to ex isting roads or streets, not including driveways? If so, generally describe (indicate whether public or private): Yes. S 328th Street (public street) will be constructed between 51st Street South and 56th Street South. 5. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe: No. 6. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. Approximately 480 new trips will be generated by the project. This includes 3 5 new weekday AM peak trips and 45 new weekday PM peak trips. 55 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 11 of 12 7. Proposed measures to reduce or control transportation impacts, if any: S 328th Street will be constructed during this project as well as payment of a transportation impact fee. The City of Auburn also has a planned improvement (TIP Project #R -9) that will realign 46th Place South and make improvements at the intersection of 46th Place South and South 321st Street which will create better traff ic conditions. PUBLIC SERVICES 1. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe: Yes, the additional homes would require all services. 2. Proposed measures to reduce or control direct impacts on public services, if any: Fire hydrants will be constructed with the street improvement to provide required fire flow for fire protection and street lighting will be installed to reduce crime potential. UTILITIES 1. Check utilities currently available at the site: Water, gas, electricity, phone, cable B. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed: The proposed utilities include: Electricity - Provided by Puget Sound Energy Water - The site is within the Lakehaven Water and Sewer District and water will be extended through the site with this project. Telephone - Provided by CenturyLink Sanitary Sewer – The site is within the Lakehaven Water and Sewer District and sanitary sewer will be extended to the site with this project. Storm - Provided by the City of Auburn Natural Gas - Provided by Puget Sound Energy Garbage Service - Provided by Waste Management Northwest Extension of these services to serve the site will be in accordance with the construction guidelines of these utility providers. SIGNATURE 56 of 628 Environmental Checklist (continued) TO BE COMPLETED BY APPLICANT ENVIRONMENTAL CHECKLIST 18355.002-SEPA Checklist.doc Page 12 of 12 The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. OWNER/AGENT SIGNATURE: DATE SUBMITTED: Senior Project Engineer Barghausen Consulting Engineers, Inc. April 30, 2021 57 of 628 1 Dustin Lawrence From:SEPA Review Notices <SEPA@pscleanair.gov> Sent:Wednesday, October 20, 2021 9:59 AM To:Dustin Lawrence; Planning-1 Subject:RE: City of Auburn - DNS & NOA - SEP19-0003 - Carbon Trails 44-Lot Preliminary Plat The Puget Sound Clean Air Agency is submitting the following public comment to this project: Any project where demolition of structure(s), earth moving and material handling, heavy equipment operations, and/or disposing of vegetative matter is to occur, is subject to Puget Sound Clean Air Agency regulations. The requirements may include, but are not limited to the following: Agency Regulation I: Article 8 – Outdoor Burning Article 9 – Emission Control Standards, Section(s) 9.03, 9.11, and 9.15 Agency Regulation III: Article 4 – Asbestos Control Standards Agency Regulations can be viewed in full on our website: http://www.pscleanair.gov/219/PSCAA-Regulations Thank you, Puget Sound Clean Air Agency Sepa@pscleanair.gov From: Dustin Lawrence <dlawrence@auburnwa.gov> Sent: Thursday, October 14, 2021 5:01 PM To: Planning-1 <Planning@auburnwa.gov> Subject: City of Auburn - DNS & NOA - SEP19-0003 - Carbon Trails 44-Lot Preliminary Plat Good evening, Attached, please find the Determination of Non-Significance and Notice of Application for the Carbon Trails 44-Lot Preliminary Plat. Additional information related to this proposal, including the project plans and supporting studies may be found at the following link: https://www.auburnwa.gov/cms/one.aspx?portalId=11470638&pageId=18075669 The comment deadline for this project is set for November 1, 2021. Please email all comments to planning@auburnwa.gov. Should you have any questions, feel free to contact me. Thank you, Dustin Lawrence, AICP, CFM 58 of 628 2 Senior Planner Department of Community Development City of Auburn | www.auburnwa.gov Office# 253-931-3092 | Cell# 253-561-2224 | dlawrence@auburnwa.gov Mailing Address: 25 W Main Street, Auburn, WA 98001 Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Click Here for Map) Customer Service Survey | Application Forms | Zoning Maps The information contained in this electronic communication is personal, privileged and/or confidential information intended only for the use of the individual(s) or entity(ies) to which it has been addressed. If you read this communication and are not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication, other than delivery to the intended recipient is strictly prohibited. If you have received this communication in error, please immediately notify the sender by reply e-mail. Thank you. 59 of 628 1 Dustin Lawrence From:KANDA,DR STACY DR STACY KANDA <stacykanda@comcast.net> Sent:Monday, October 25, 2021 8:57 AM To:Planning-1 Subject:Carbon Trails Attachments:DEVELOPMENT DOCUMENT BEST.pdf Mr Lawrence, I have attached a letter with my concerns about the Carbon Trails development. Byran Stowe has a history of problems with development with which he has developed in the past. There are many "red flags" in his history that are of concern. The local residents and the City of Auburn could be at risk. There is no plan to improve 51st Avenue South for the increased traffic. This must be addressed by the City of Auburn or King County. I believe since Auburn has incorporated the area King County will probably make the city make the improvements. We will have to contact them about this. This is a safety issue for pedestrian and vehicle traffic due to the width if the street. lack of sidewalks and lighting. Respectfully, Stacy Kanda, DDS 60 of 628 61 of 628 62 of 628 63 of 628 64 of 628 65 of 628 66 of 628 67 of 628 68 of 628 69 of 628 70 of 628 71 of 628 72 of 628 73 of 628 74 of 628 75 of 628 76 of 628 77 of 628 1 Dustin Lawrence From:Bryan and Danielle <dizzydirk@live.com> Sent:Monday, November 1, 2021 4:18 PM To:Planning-1 Cc:Jeff Tate; Shannon Howard; Dustin Lawrence Subject:RE: Notice of Application & Determination of Non-Significance for Carbon Trails 44-Lot Preliminary Plat (SEP19-0003) Jeff Tate Director, Department of Community Development 25 West Main Street Auburn, WA 98001 RE: Notice of Application & Determination of Non-Significance for Carbon Trails 44-Lot Preliminary Plat (SEP19-0003) Mr. Tate: Our property will be significantly impacted by this project and we absolutely want to be included as a party of record. We wish to receive notice of and participate in any hearings related to this project. We also are requesting a copy of the decisions once made. Please confirm you have received this email before the November 1st @ 500pm deadline. Thank you, Bryan Peterson Danielle Zaklan 32720 51st Ave S Auburn, WA 98001 253.653.2713 78 of 628 1 Dustin Lawrence From:fran wold <frans.household@gmail.com> Sent:Monday, October 25, 2021 3:38 PM To:Dustin Lawrence Subject:Re: Carbon Trails Directly west of my property. The west side of 56th. On Mon, Oct 25, 2021 at 7:57 AM Dustin Lawrence <dlawrence@auburnwa.gov> wrote: Hi Frances, Thank you for your comments. I will share with the applicant. Can you let me know if the trees in question are to the north, south, east, or west of your property? Thank you, Dustin Lawrence, AICP, CFM Senior Planner Department of Community Development City of Auburn | www.auburnwa.gov Office# 253-931-3092 | Cell# 253-561-2224 | dlawrence@auburnwa.gov Mailing Address: 25 W Main Street, Auburn, WA 98001 Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Click Here for Map) Customer Service Survey | Application Forms | Zoning Maps From: fran wold <frans.household@gmail.com> Sent: Sunday, October 24, 2021 1:11 PM 79 of 628 2 To: Planning-1 <Planning@auburnwa.gov> Subject: Carbon Trails Dear Mr. Lawrence~ I received the card from your department regarding the proposed development of 44 new homes. I live across the street on the corner of 56th and 328th. My concern is the trees that line the property of 32727 on 56th. I have grown dependent on the shelter they provide from winds and heat from the sun. For me especially, those trees are a Godsend. In practical terms I don't see any good reason they should be cut down. They line the property line and should not interfere with the progress of that building site. I am hoping there is a way to respect the protection they provide and will see a way to leave them where they are. Please let me know if this is possible in any way. Respectfully, Frances Wold 5604 S. 328th St. 253-876-0817 The information contained in this electronic communication is personal, privileged and/or confidential information intended only for the use of the individual(s) or entity(ies) to which it has been addressed. If you read this communication and are not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication, other than delivery to the intended recipient is strictly prohibited. If you have received this communication in error, please immediately notify the sender by reply e-mail. Thank you. 80 of 628 1 Dustin Lawrence From:Dustin Lawrence Sent:Wednesday, December 1, 2021 4:32 PM To:KANDA,DR STACY DR STACY KANDA Cc:Shannon Howard; James Webb Subject:RE: Carbon Trails Hi Dr. Kanda, Thank you again for submitting your comments to the City of Auburn. Below, is a list of responses from City staff regarding your concerns. These were also shared with the applicant. As a reminder, the public hearing for this matter is scheduled for December 15, 2021 at 5:30 PM via ZOOM. Additional information is included at the following link: https://www.auburnwa.gov/cms/one.aspx?portalId=11470638&pageId=18075669 WETLAND, WILDLIFE, & HOUSING CONCERNS Dustin Lawrence, AICP, CFM, dlawrence@auburnwa.gov The applicant has provided critical area report, prepared by a professional wetland scientist (PWS), confirming the location of any onsite or nearby wetlands and their respective buffers. City staff are in agreement with the analysis conducted by the applicant’s consultant, which confirms the presence of a Category III wetland with a 50 foot wide buffer on the north portion of the property. No impacts to vegetation are proposed within this wetland area and its hydrology will be maintained. Regarding wildlife, the City provided the SEPA determination (environmental analysis) to multiple contacts, including WA Department of Ecology and WA Fish and Wildlife. Neither agency responded with any concerns related to potential wildlife impacts resulting from the proposal. Generally, the only endangered species and habitat we come across in Auburn are limited to the Bull Trout, Steelhead, and Chinook Salmon, all of which are limited to river and stream areas. I am aware of the Northern Spotted Owl being of concern, but their habitat or presence hasn’t been seen in the Puget Sound Lowlands for quite some time. Other species, such as squirrels, deer, racoons, etc., are not protected. It should be noted that the City of Auburn is located within an Urban Growth Area, in which new housing and development should be accommodated within our City limits as opposed to more rural areas. By allowing growth within our City limits, we are limiting that amount of pressure and potential loss of far more ecologically valuable areas that haven’t already been affected by urban development. This ensures more wildlife habitat, wetlands, and other sensitive areas are protected. Regarding the housing impacts, while one existing residence will be removed, it will be replaced with a new home when the development is completed. The City of Auburn does not have any specific regulations for aesthetics related to housing, with the exception being height limits, setbacks, and lot coverage. The applicant will be meeting these requirements, as no deviations or variances to these standards was sought. With your concerns being shared with the applicant, it is possible that they voluntarily attempt to preserve some trees or orient the houses in a way that won’t have a visual impact to your property. However, by meeting the City’s prescriptive development standards (setbacks, height, lot coverage, etc.), there isn’t much else that would be required of the developer. STORM DRAINAGE CONCERNS Shannon Howard, PE, CFM, showard@auburnwa.gov Reference 7 and 8: The detention pond has been shown to meet all applicable stormw ater requirements required by the Washington State Department of Ecology and the City for flow control and water quality. The Environmental Protection 81 of 628 2 Agency delegates management of stormwater runoff mitigation and management to the Washington State Department of Ecology. Ecology requires that the City of Auburn implement nine Minimum Requirements for Stormwater Management, with flow control and water quality requirements included in the Minimum Requirements. The City has adopted the Minimum Requirements as part of the Engineering Design Standards that are applicable to all projects. Hydrologic modeling for flow control and water quality using the Western Washington Hydrology Model is required to demonstrate compliance with the standards. The applicant has provided this modeling as part of the preliminary plat review and demonstrated compliance with the Minimum Requirements TRANSPORTATION CONCERNS James Webb, PE, jwebb@auburnwa.gov I will send you a separate response related to transportation later this week. Feel free to contact me should you have any additional questions. Thank you, Dustin Lawrence, AICP, CFM Senior Planner Department of Community Development City of Auburn | www.auburnwa.gov Office# 253-931-3092 | Cell# 253-561-2224 | dlawrence@auburnwa.gov Mailing Address: 25 W Main Street, Auburn, WA 98001 Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Click Here for Map) Customer Service Survey | Application Forms | Zoning Maps From: KANDA,DR STACY DR STACY KANDA <stacykanda@comcast.net> Sent: Monday, October 25, 2021 8:57 AM To: Planning-1 <Planning@auburnwa.gov> Subject: Carbon Trails Mr Lawrence, I have attached a letter with my concerns about the Carbon Trails development. Byran Stowe has a history of problems with development with which he has developed in the past. There are many "red flags" in his history that are of concern. The local residents and the City of Auburn could be at risk. There is no plan to improve 51st Avenue South for the increased traffic. This must be addressed by the City of Auburn or King County. I believe since Auburn has incorporated the area King County will probably make the city make the improvements. We will have to contact them about this. This is a safety issue for pedestrian and vehicle traffic due to the width if the street. lack of sidewalks and lighting. Respectfully, Stacy Kanda, DDS 82 of 628 1 Dustin Lawrence From:Dustin Lawrence Sent:Monday, November 29, 2021 2:34 PM To:Bryan and Danielle Subject:RE: Notice of Application & Determination of Non-Significance for Carbon Trails 44-Lot Preliminary Plat (SEP19-0003) Attachments:PLT19-0002 - Postcard Public Notice.pdf Hi Bryan, If not received yet, here is the notice of hearing document. The hearing is scheduled for Dec. 15 th at 5:30 PM via ZOOM Thank you, Dustin Lawrence, AICP, CFM Senior Planner Department of Community Development City of Auburn | www.auburnwa.gov Office# 253-931-3092 | Cell# 253-561-2224 | dlawrence@auburnwa.gov Mailing Address: 25 W Main Street, Auburn, WA 98001 Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Click Here for Map) Customer Service Survey | Application Forms | Zoning Maps From: Bryan and Danielle <dizzydirk@live.com> Sent: Monday, November 1, 2021 4:18 PM To: Planning-1 <Planning@auburnwa.gov> Cc: Jeff Tate <jtate@auburnwa.gov>; Shannon Howard <showard@auburnwa.gov>; Dustin Lawrence <dlawrence@auburnwa.gov> Subject: RE: Notice of Application & Determination of Non-Significance for Carbon Trails 44-Lot Preliminary Plat (SEP19- 0003) Jeff Tate Director, Department of Community Development 25 West Main Street Auburn, WA 98001 RE: Notice of Application & Determination of Non-Significance for Carbon Trails 44-Lot Preliminary Plat (SEP19-0003) Mr. Tate: Our property will be significantly impacted by this project and we absolutely want to be included as a party of record. We wish to receive notice of and participate in any hearings related to this project. We also are requesting a copy of the decisions once made. Please confirm you have received this email before the November 1st @ 500pm deadline. 83 of 628 2 Thank you, Bryan Peterson Danielle Zaklan 32720 51st Ave S Auburn, WA 98001 253.653.2713 84 of 628 1 Dustin Lawrence From:Dustin Lawrence Sent:Monday, November 29, 2021 2:48 PM To:fran wold Subject:RE: Carbon Trails Hi Frances, I shared your comments with the developer. I am not sure at this point if they plan on retaining the trees in question, but will bring it up to the hearing examiner for the upcoming Dec. 15 th hearing. I will note that we do not have a tree protection ordinance at Auburn, only that trees in critical areas are required to remain and significant trees within the perimeter of commercial developments. I still appreciate your comment and it is entirely possible the developer makes an attempt to retain these trees. Thank you, Dustin Lawrence, AICP, CFM Senior Planner Department of Community Development City of Auburn | www.auburnwa.gov Office# 253-931-3092 | Cell# 253-561-2224 | dlawrence@auburnwa.gov Mailing Address: 25 W Main Street, Auburn, WA 98001 Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Click Here for Map) Customer Service Survey | Application Forms | Zoning Maps From: fran wold <frans.household@gmail.com> Sent: Monday, October 25, 2021 3:38 PM To: Dustin Lawrence <dlawrence@auburnwa.gov> Subject: Re: Carbon Trails Directly west of my property. The west side of 56th. On Mon, Oct 25, 2021 at 7:57 AM Dustin Lawrence <dlawrence@auburnwa.gov> wrote: Hi Frances, Thank you for your comments. I will share with the applicant. Can you let me know if the trees in question are to the north, south, east, or west of your property? Thank you, 85 of 628 2 Dustin Lawrence, AICP, CFM Senior Planner Department of Community Development City of Auburn | www.auburnwa.gov Office# 253-931-3092 | Cell# 253-561-2224 | dlawrence@auburnwa.gov Mailing Address: 25 W Main Street, Auburn, WA 98001 Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Click Here for Map) Customer Service Survey | Application Forms | Zoning Maps From: fran wold <frans.household@gmail.com> Sent: Sunday, October 24, 2021 1:11 PM To: Planning-1 <Planning@auburnwa.gov> Subject: Carbon Trails Dear Mr. Lawrence~ I received the card from your department regarding the proposed development of 44 new homes. I live across the street on the corner of 56th and 328th. My concern is the trees that line the property of 32727 on 56th. I have grown dependent on the shelter they provide from winds and heat from the sun. For me especially, those trees are a Godsend. In practical terms I don't see any good reason they should be cut down. They line the property line and should not interfere with the progress of that building site. I am hoping there is a way to respect the protection they provide and will see a way to leave them where they are. Please let me know if this is possible in any way. Respectfully, Frances Wold 5604 S. 328th St. 86 of 628 3 253-876-0817 The information contained in this electronic communication is personal, privileged and/or confidential information intended only for the use of the individual(s) or entity(ies) to which it has been addressed. If you read this communication and are not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication, other than delivery to the intended recipient is strictly prohibited. If you have received this communication in error, please immediately notify the sender by reply e-mail. Thank you. 87 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallR                                       88 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR89 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR90 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallR91 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR92 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR93 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR94 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR95 of 628 CARBON TRAILS96 of 628 CARBON TRAILS97 of 628 CARBON TRAILS98 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR99 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR100 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallRCAUTION:101 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR102 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallRSCALE: 1"=40'103 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallRSCALE: 1"=40'104 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallRSOD LAWN IN ALL LANDSCAPE STRIPS,TYPICAL. LAWN HATCH NOT SHOWN.LANDSCAPE CONTRACTOR TOCALCULATE QUANTITIESREFER TO CITY OF AUBURN STREET TREEPLANTING/STAKING STANDARD DETAILTRAFFIC-14. GATOR BAGS OR APPROVED EQUALARE REQUIRED FOR ALL STREET TREES.MAINTENANCE SHALL INCLUDE THE BAGSDURING SUMMER MONTHS 2X PER WEEK.HYDROSEED SLOPES WITHIN STORM POND.SEE SEED LIST THIS SETSTREET TREES OMITTEDDUE TO SLOPESSTREET TREE OMITTEDDUE TO CONFLICTWITH HYDRANTSTREET TREE OMITTEDDUE TO CONFLICTWITH LUMIERE POLEALL STREET TREESOMITTED WITHIN SIGHTDISTANCE TRIANGLE, TYP.ALL STREET TREESOMITTED WITHIN SIGHTDISTANCE TRIANGLE, TYP.105 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallRHYDROSEED SLOPES WITHIN STORM POND.SEE SEED LIST THIS SETSTREET TREE OMITTED DUETO CONFLICT WITH HYDRANTAND LUMIERE POLEALL STREET TREESOMITTED WITHIN SIGHTDISTANCE TRIANGLE, TYP.ALL STREET TREESOMITTED WITHIN SIGHTDISTANCE TRIANGLE, TYP.106 of 628 SCALE: 1"=200'N107 of 628 SCALE: 1"=50'N108 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR109 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR110 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR111 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR112 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR113 of 628 January 14, 2019 Bryan Stowe PO Box 1054 Sumner, Washington 98390 RE: Critical Area Report – Carbon Trails City of Auburn, Washington SWC Job #17-216 Dear Bryan, This report describes our observations of jurisdictional wetlands, streams and buffers on or within 200’ of the proposed Carbon Trails Plat, located on Parcels#926280-0295, #0320& #0313 located between 51st Avenue SE and 56th Avenue SE in the City of Auburn, Washington (the “site”). The site consists of an 11.38 acre irregular shaped accumulation of 3 parcels, located within the NW ¼ of Section 14, Township 21 North, Range 4 East of the W.M. METHODOLOGY Ed Sewall of Sewall Wetland Consulting, Inc. inspected the site on December 4, 2017 and September 24, 2018. The site was reviewed using methodology described in the Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory, 1987), and the Western Mountains, Valleys and Coast region Supplement (Version 2.0) dated June 24, 2010, as required by the US Army Corps of Engineers and City of Auburn. Soil colors were identified using the 1990 Edited and Revised Edition of the Munsell Soil Color Charts (Kollmorgen Instruments Corp. 1990). Sewall Wetland Consulting, Inc. PO Box 880 Phone: 253-859-0515 Fall City, WA 98024 114 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 2 Above: Vicinity Map of the site. 115 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 3 OBSERVATIONS Existing Site Documentation. Prior to visiting the site, a review of several natural resource inventory maps was conducted. Resources reviewed included the National Wetland Inventory Map and the NRCS Soil Survey online mapping and Data and the King County iMap website with wetland and stream layers activated. Soil Survey According to data on file with the NRCS Soil Survey, the majority of the site is mapped as moderately well drained Alderwood soils of various slopes. Alderwood soils are not considered “hydric” or wetland soils. Above: USDA Soil Survey Map of the sit National Wetlands Inventory (NWI) According to the NWI map for the site, are no wetlands on or near the site. The closest wetland is approximately 1,000’ northwest of the site. 116 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 4 Above: National Wetlands Inventory Map of the site. WADNR Fpars Stream Mapping According the WDNR Fpars stream mapping of the site, there are no streams on or near the site. 117 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 5 Above: WDNR Fpars stream mapping. Washington Department of Fish and Wildlife Priority Habitats Data Search According to the WDFW Priority Habitat Website with Public access layers activated, there are no priority habitats or species points located on or near the site. 118 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 6 Above:WDFW Priority Habitats and Species Map of the area of the site. Field observations Uplands The site consists of a mix of mature douglas fir forest, and a disturbed shrub and sapling covered area near the north central part of the site. A single family home with a large shop building is located on the eastern side of the site. The forested areas of the site contain large douglas fir in the overstory with red huckleberry, Himalayan blackberry, stinging nettle, sword fern, salal, creeping blackberry, vine maple, indian plum and hazelnut in the understory. The central disturbed portion of the site appears to be old fill covered with weedy species such as Himalayan blackberry, scotch broom, some reed canary grass and alder and cottonwood saplings. Soil pits excavated within the upland areas revealed gravelly sandy loam as well as a gravelly fill material soils in disturbed areas with colors of 10YR 3/3-3/4. 119 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 7 Wetlands A single forested wetland was observed along the north edge of the site. This wetland is approximately 1 acre in size and discharges to a culvert located along the south end of the wetland. The location of the outlet of the culvert is unknown and was not observed on-site or south of the site, the logical outlet location. Wetland A “Wetland A” onsite consists of the south edge of the wetland which was flagged with flags A1-A8. The wetland extends off-site to the north and is approximately 1 acre in size based upon aerial photograph measurements. The wetland is vegetated with an overstory of red alder and pacific willow, with crabapple, hardhack and lady fern in the understory. Soil pits excavated within the wetland revealed a mucky gravelly loam with a soil color of 10YR 2/2 with few, fine, faint redox concentrations. Soils were inundated with 3” of standing ware during our December 2017 delineation of the wetland. Using the US Fish and Wildlife Wetland Classification Method (Cowardin et al. 1979), Wetland A would be classified as PFO1C (palustrine, forested, deciduous, seasonally flooded). Using the 2014 WADOE Wetland Rating system and rating the wetland as a depressional type wetland, this wetland scored a total of 16 points with 4 points for habitat. This indicates a Category III wetland. A Category III wetland with 4 habitat points in the City of Auburn (AMC 16.10.090.E.1) have minimum buffer width of 25’, and a maximum buffer of 50’ buffer measured from the wetland edge. Proposed Project The proposed project is the construction of a 43 lot residential plat with associated infrastructure. No impact to the Category III wetland or its associated 50’ buffer is proposed. 120 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 8 If you have any questions in regards to this report or need additional information, please feel free to contact me at (253) 859-0515 or at esewall@sewallwc.com . Sincerely, Sewall Wetland Consulting, Inc. Ed Sewall Senior Wetlands Ecologist PWS #212 Attached: Data sheets Rating Forms 121 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 9 REFERENCES Cowardin, L., V. Carter, F. Golet, and E. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, FWS/OBS-79-31, Washington, D. C. Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual, Technical Report Y-87-1. U. S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, Mississippi. Muller-Dombois, D. and H. Ellenberg. 1974. Aims and Methods of Vegetation Ecology. John Wiley & Sons, Inc. New York, New York. Munsell Color. 1988. Munsell Soil Color Charts. Kollmorgen Instruments Corp., Baltimore, Maryland. National Technical Committee for Hydric Soils. 1991. Hydric Soils of the United States. USDA Misc. Publ. No. 1491. Reed, P., Jr. 1988. National List of Plant Species that Occur in Wetlands: Northwest (Region 9). 1988. U. S. Fish and Wildlife Service, Inland Freshwater Ecology Section, St. Petersburg, Florida. Reed, P.B. Jr. 1993. 1993 Supplement to the list of plant species that occur in wetlands: Northwest (Region 9). USFWS supplement to Biol. Rpt. 88(26.9) May 1988. USDA NRCS & National Technical Committee for Hydric Soils, September 1995. Field Indicators of Hydric Soils in the United States - Version 2.1 122 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR123 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallR124 of 628 WETLAND DETERMINATION DATA FORM - Western Mountains. Valleys* ami Coast Region Applicant/Owner: Investigators) _ Landform (hilislope, terrace, etc) Subregfon (LRR) Soil Map Unit Name: _ g& ST" . City/County:. . Sampling Date: , Sampling Point:. . Sedton, Township, Range _ . Lai. . Local relief (concave, convex, none).. , Long: . Slope (%):. . Datum:. . NWt classification:. Are climatic / hydrotogtc conditions on the site typical for this ttme of year? Yes Ho (tf no, explain in Remarks.) Are Vegetation , Soil . or Hydrology significantly disturbed? Are 'Normal Circumstances* present? Yas No Are Vegetation . Soil _______ or Hydrology naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS - Attach site map showing sampling point locations, transects, important features, etc. Hydrophyte Vegetation Present? Hydric Soil Present? Wetland Hydrology Present? Y«._£^o_. Yes No_ Is the Sampled Area within • Wetland? 1 Yu No Remarks VEGETATION - Use scientific names of plants. Tree Stratum (Plot ira _____ 1 nl'vvL r-^br—\ Absolute % Cover - fc* ... Dominant Indicator Species? Status *_c Seolinarenrob Stratum (Plot size: I . "Tola! Cover Hera Stratum (Plotuze . TSgW If -Jtttf. - Total Cover Woodv Vine Stratum (Plot size: _ % flare Ground in Herb Stratum _ Dominance Test worksheet: Number of Dominant Species That Are OBL. FACW. or FAC: (A) Total Number of Dominant Species Across AS Strata: Percent of Dominant Species j v&«_i That Are OBL. f ACW. or FAC: ..S Prevalence Index worksheet: , , Total % Cover of: _ Multiply t?y: OBL species FACWspeciss . FAC species FACU species UPL species Column Totab: . * 1 - -. x 3 * _ . x4= _ *5 = _ . (A) _ Prevalence Index * B/A * . Hydraphvj^Vegetaflon Indicators: _^0<)mmance Teat is >50% Prevalence Index is S3.Q! , , Morphological Adaptations' (Provide supporting data in Remarks or on a separate sheet) Wetland Non-Vascular Plants1 Problematic Hydroptiytic Vegetation' (Explain) 'Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytfe Vegetation Present? Yss US Army Corps of Engineers Western Mountains, Valleys, and Coast - interim Version SOIL Sampling Point: Profile Description: {Describe to the depth needed to document th* Indicator or confirm the absence of indicators.) Depth ...Mar*.. Miro«.. _^__Vz__ Color fi Redox Features^ Texture Type; C=Concentration. p^Degjelion. RM=ReducedMatrix, CS-CoyeredorC^j^S^ .Location: Pt=Ppre Lriing. M^Matrk Hydric Soft Indicators: (Applicable to all LRRs, unless otharwlss noted.) . HistosoHAI) . Histic Epipedon (A2) . Stock Histic (A3) . Hydrogen Sulfide (M) . Depleted Below Dark Surface (A11) . Thick Dark Surface (A1Z) . Sandy Mucky Mineral (S1) . Sandy Gieyed Matrix ($4) , Sandy Redox (S5) . Stripped Matrix <S6) . Loamy Mucky Mineral (F1) (except MLRA 1) . Loamy GJpyad Matrix (F2) De*«SdMatiU (F3> r^edox Dark Surface (F6) . Depleted Dart Surface <F7) . Redox Depressions (F6) Indicators for Problematic Hydric Soils': . 2 cm Muck (A10) . Red Parent Material (TF2) „ Other (Explain _i Remarks) indicators of hydrophylk; vegetation and wetland hydrology must be present, unless disturbed or probtematoc Restrictive Layer (if present): Type: Depth (inches):, Hydric Soil Present? Yes. HYDROLOGY Wetland Hvp>dfogy Indicators: lcUcators, (m|nirnum of one required; check all that apply) _Z Surface Water (A1) High Water Table (A2) Saturation (A3) _ Water Marks (Bt) Sediment Deposits (B2) Drift. Deposits (B3) _ Algal Mat or Crust (B4) Iron Deposits (86) Surface Soil Cracks (86) Inundation Visible on Aerial Imagery (B7) Sparsely Vegetated Concave Surface (Bfl) . Water-Stained leaves (89) (except MLRA 1,2,4A, and 46) . Salt Crust (B11) . Aquatic Invertebrates (813) . Hydrogen Sulfide Odor (CI) . Oxidized Rhizospheres along Living Roots (C3) . Presence of Reduced iron (C4) . Recent Iron Reduction in Tilled Soils (C6) . Stunted or Stressed Plants (D1) (LRR A) , Other (Explain in Remarks) Secondary, ImMcators (2 or.rnorc reflyyed) Water-Stained Leaves 189) (MUM 1, 2, 4A, and 4B) Drainage Patterns (B10) Dry-Season Water Table (C2) Saturation Visible on Aerial imagery (C9) Geomorahic Position (02) Shallow Aqurtard (03) FAC-Neulral Test <D5) Raised Ant Mounds (D6) (LRR A) Frost-Heave Hummocks (D7) Field Observations: Surface Water Present? Yes „ No Depth (inches): J Water Table Present? Yes _ No Depth (inches): Saturation Present? Yes _ No Depth (inches); Wetland Hydrology Present? Yes No . (includes capHtarv fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast - Interim Version 125 of 628 3 Project-Slta:.. Apptlcarit/Owiwr: _ InvastiaMofts) Landform fnHWopa, Sl*r»gionaR«)' Soil Map Urrf Name. WETLAND DETERMINATION DATA FORM - WwtMT) Mountains, Valteys. and Coast Rofllon C<*~W- T>«~ If CHICax*: Av^VS~/>J SWnoDat.- I T-~ *j ~1 ^ _ Sampling Dane _ . Samp-wvg Point' . . Secffon. Township, Rang*: . Local relief (concave, convex, none);. Long: Stale- ^VA . Slope {%);_ 1 clasvftcatiori:, Are cferwrtic / hytiroJogic cc*KrteortS on the site typical for this Ttme of year? Yes__j^_No (If no, explain in Remarks) Are Vegetation , SoK . or Hydrology significantly disturbed? Are "Normal Circumstances* present? Yes , No Are Vegetation , Sofl ..„,.,...,.. or Hydrology naturally problematic? <tf needed, explain any answers in Remarks) SUMMARY OF FINDINGS - Attach site map showing sampling point locations, transacts, important features, c HydroohySeVepetstk-m Present? Hydric Son Present? Vlnaiand Hydrotogy Present? Yes Yes Yes No ^ Jt tha Sampled Ami within I Wetland? Ye* No Rat-nark* VEGETATION - Use scientlfle names of plants. _ (Ptotefta: Absolute St. Cover Dominant Inaicatar ma _» Total Cover PA I (Plot SUA: ij * i «Totai Cover Woodv Vine Stratum (Ptot size:. % Bare Ground in Herb Stratum _ Doa&iancs fast worWiset: Nwtber of Dominant Species That Are OBL, FACW. or FAC: Total Number of Dominant Species Across All Strata: Percent of Dominant Speojes That Aw OBL, FACW. or FAC; m (B) (A®) Prevaisnce In-da* wrtcsh-eet: Total %Cowr of: MuHiPlvbv: OBL species FACW species . FAC species . FACU species . 1 spades , Column Total*. , *1 x5» . .(A) . . (B) Prevalence Index * B/A » . Hydrophytfe Veo^rtatton Indicators: Owrwrence Test to >50% Prevalence Index is £3 0T Morphological Adaptations' (Provide sapportirig data; in ftenierfcs or on a separate sheet) Wetland Non-Vaacutar Plants' Problematic Hyefrophytic Vegetation' (Explain) 'indicators of hydric soil and wetland hydrology must be present, untess disturbed or problematic Vegetatton US Army Corps of Engineers Wast am Mountains. Valleys, and Coast - Interim Version SOIL Sampling Point: Profile DascHptton; (Desc*^ tothe depth nesdad todwmiWntth* MlcaW or cMfirm the absence erf Indicators.) Remarks 'Type: C^Coneemraiion, t>Deotelipn. RM-^aduosd Matrix, CS-Covered or Coaled Sand Grains. ,, ^Location:, Pt°Pora tmina t^Matrk, Hydrtc Soil Indtoetofs: (Applicable la a HiatosoKAD _ HWfcE|jipedon<A2> BoK*HHIio<A3l HydrojenSul»o»(A4] Depleted BatowDartcSurtaceCAU) Tnx* Dark Surfaca (A12) Sandy Mucky ntnersl (St) Sandy Gler°dM«lrr»i&l) t LRRa. unless otherwise noted.) Sandy Redox (S5> Skipped Matrix (So) Loamy Mucky Mineral (F1) (except MLRA 1) Loamy Gieyed Matrix (F2) _ Depleted Ms«1x(F3) Redox Oar* Surtaoe (F6> Depleted l>*8tir6ice(F7> Redox Depressions (F8) trxtteators tor Probfamatlc Hydric SOHS 2onMuck(A10) n-sd Parent Material (TF2) Other (.Explain in Remants) :^idxjators of hydraphyHc veoetation and watlar)d hydrolooy must be present, unless distiirtjed or problematic. Restrictive Layer (If present): Type: Oeoth ttnehea): Hydric Soil present? Yes _ Wo ' ^ Remarks: HYDROLOGY WeOend Hydrotojy ItxDOitoni: Sdrteos Water (A1) High Water T«*le(A2> Saturation <A3) _ Water Marks (Bl I Sediment Deposits (B2) Orttt Deposits (B3) A)oalMatorClust(M) ban Deposits <B5) _ Surlam Son Cracks (86) lmmdlllionVls«)le on Aerial lnageiy(B7) Sparsely Vegels^ Crjnrave Slinaos <88) _ Water-SlalruW Leaves IBs) (except MLRA 1,2,<A.and4e) Sa«Crtist(B1l) Aquatic rnvertebrates (813) _ HydroaanSu«deOdor(C1) OxuiizsdRhiiospnMMlrtongLtariQ , Presence of Reduced tron(C4) Recant Iron Reduction rnTIUcd Sons (08) _ SHinledwStlss»edPllintj(D1)(U«RA) Omer(E)vlalninRamiala) awndary Inacatoe B yrecxe fegurej.) _ Water-Stained Leaves IBB| (MLRA t, 3, 4A, and SB) Dralnaoe PaUems(BtO) Ory-Saason Watm Table (C2I _ 8atunriionVlsa^onAenaltmage(y(CS) _ Geofnorphic Posroon (02) ShaBcwAisiiiatd (03) _ FAC.NeutralT«st(D5) _ RaWK)AT7lMourids(06)(LRRA) Fn«4le«veHumrnoci(s(OT) Field Ooservetians: Suriaos Water Present? Wawt Table Present? Saturation Pwasnt? (tneluoas capHam Wnoe) Wetland Hydrology Present? Yes. Describe- Recorded Data (stream gauge, monitgdna well, aerial photos, previous itisoections), ft available: Remarks* US Army Corps of £ngjneers Western Mountains, Valleys, and Coast - trterim Version 126 of 628 PrajectrSiB):. WETLAND DETERMINATION DATA FORM - Western Mountains, Valleys, and Coast Region App6cant/r>*nar: lnvw%rtor{«) ___ . Samptmg Data-_ Sampkng Point . . Section. Tovwwhip, Ran&»: _ Landform (hiMsiope, torsoa. etc): Stjtoagton (LRR) Soil Map Unit Name:_ . Local relief (concava, convex, none): „ Long: . NW1 aassftatlon:. Aradinietio/hvorologlccc«KWio^ Yes — Wo (If no, explain in Remarks.) Are Vegetation ,Soit ^wHyAotagy s^tr-aneydisturbed? Are*Norntatr^cwretaocas'prssent? Ye*_J Are Vegetation .Sott^ , or Hydrology naturally pmblenianc? (It needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Hyo>ophyt»c Veo^taten Present? Hydric Soil Present? Wetland Hyorotooy Present? III: _le£?™ ____*»-''" No -S" No__Z M the Sampled Ann within a Wetland? Yes No Remarks VEGETATION - Use sclentifie t tame 1 of plants. Ttse Stratum (Ptolsize;, Absolute % Soger. L>m»nant Indicator 5 gftlyij * Total Cover Hei-b (Plot axe ...t ,;.»g, 3 => TotaJ Cover ^2 Wjc^vyiaSIri^ {Ptotsoe:. % Bare Ground in Herb Stratum DMittoajtee Test wwttshaefc ' Number of Dominanl Species That Are 081. FACW. or FAC; Total Number of Dominant Spades Across All Strata: Pe-rxwvt of Dominant Species That Are OBI, FACW, or FAC: Prevalence Index wortonsst: tVfutyjply bv: OBI species FAeWspeefts , FAC species _ FACU species . UPL apectes _ Column Totab: . . (A) . Prevalence index »B/A« Myo^SJBcVeS j^Uoroinence 7 V*98tabon Indicators: Test is >80% Pmvatenoe Index is S3 0T Moroboiog^cai Adaptations' (Provide supporting data in RernerHs or on a separate sheet) Wetland Non-Vascular Plants' Problems!*: Hydrophytic Vec/staton1 (Expiatn) indfcators of hydnc soil and wetland hydrology must be present, unless disturbed or proWematoc Hydrophyfio Ve«Btatton Prseent? US Army Corps of Engineers Western Mountslrta. Valleys, and Coast - Interim Version 'Type: c-<frncatttnjtaon. p»Dep|ejion. RM-pReduoed Matrix, CS'Covered or Coated Sand Grams. location: PL"Pow Lwing, M^Matrit, Hydnc SOU Iridlcators: (AppncaMe to all LRRs, unless othstwlM noted.) Sandy Redox (SS) Stripped Matrix (S6) Loamy Mucky Mineral (Ft) (except MLRA 1) Loamy Sieved Matrix (F2) _ Depleted Matrix (F3) Redox Dark Surtace(P6) Depleted Dark Surface (F7) Redox Depressions (FB) »(A1> . «itic6pp«Oon(A2) . Black Mslic (A3) . Hydrogen SuHde(M) . Depleted tfck>wf^Si»<at»(A1t) . Thii* Die* Surface (A12) . Sandy Mucky Mineral (S11 Indicators tor Problematic Hydric So*' _ 2cmMuck(A10) Red Parent Material (TF2) Other (Explain xt Romarits) -Ntidtoetrjrs of hydrophyte vegetation and wetland hydtology must bs present tiTtessdatiirtwytorprobB^ Restrictive Layer (If present): Type: Depth (Inches): Hydric Soil Present? Yes Ho ^ Remarks: HYDROLOGY WeOand Hydrology Indicators: Primary WjceWrg MnyjtaT.ctr^ all rhy apply) Surface Water (A1) High Water Tat* (A2) Saftaatlon (A3) _ Water Marks (B!) Serfcneni Deposits (B2) ._ »m Deposits <B3) Algal Mat or Crust (B<) Iron Deposits (B6) Surface So) Cracks (B8) Inunrjation VniWe on Aerial Imageiy (87) SparsetyVagata)odCi>nM«BSunaoi<BS) _ Water-Stelrwd Leaves (BS) (except MLRA 1.2.4A. «nd<B) Salt Crust (Btl) Aq^lic Inwirhbratet (BI3I Hydrogen SuHirJe Odor (C1) OxidiswtRhizospherttsirkxtgLivi^ . Presence of Reduced Iron (C«) Recent don Reductionm Tilled Soils (CS) _ l*n«dwStte5SSdF1e^(OT)(U»JlA) Omar (Explain in Remarks) Secondary Irxticatora (2 or-more tBoured'l Water-Stained leaves IBS) (MLRA 1.1, 4A, and SB) Drainage Patterns (B10) Ory^aason Water Table (C2) _ SatjJ^at^on^l1sibleonAari«irnar^ „ Gcomorphic Position (D2) Shallow Antrtard (03) FAttsr!utralT«st(DS) _ Ratsod Ant Mounds (06) (LRR A) Frost-Heave Hummocks (0?) Field Observations: Suifaos Water Present? Yes Water Tat* Present? Yes Saturation Present? Yes (includes capjfjaiv MtlflB) witace(t») j Wo j^yx Deps^jlttcnas): Onchee): Depth I Inches): Wetland Hydrology Pr««ent7 Yos_ bescnba Recorded Dau) (stream gauge, rrwnitonrig trvefl, aeriat photos, previous jrtacections), i Remarks: US Army Corps of Engirteers Western Ivkjuntains, Valleys, and Coast - Interim Version 127 of 628 WETLAND DETERMINATION DATA FORM - Western Mountains, Vallays. and Coast Region Projects** AswjBMntrOwnen . Investiowiorfs). . CiyCounty:. t Secltan. Township, Rang*: _ Uandform (hMstope, terraoa. etc ) Subregkm (LRR) Soil Map Unit Name._ . Local relief (concave, convex, none);_ long: . Slope , NW1 dassiftcsfton:. Am cfimatic,' hyrlroloojc condft»oo« on the srtt typical for this rtme of year? Yes r^\ (If no, eipJatn in Remarks.) Are Vagetetion So* ,or Hydrolooy staniftcantfy oHBbjreea"' Are "rtomai Ctrcurrstetnces* peasant? Yes No Are Vegetation , Son „ , or Hydrology naturally prabtematic? <tf needed, explain any answers in Ftemarits.) SUMMARY OF FINDINGS - Attach sit* map showing sampling point locations, transacts, important fsaturas, etc. t-rydraphytie Vegetation Present? Yes •Is the Sampled Anu Hydric Soli Present? Yes No -^t^ edStnatWetland? Yes No Wetland Hyotology Ptesent? res . N° ^ Yes Remark* VEGETATION - Use scientific names of p lants. tomfoance Test workefieet: t>fc)imber of Dominant Species That Are OBL. FACW. or FAC: Total Number of Dominant Spades Across AH Strata: Percaivt of Dvrninent Spaas* That Are 1361, FACW, or FAC: TreeBfratom (PJptaiza: } J&£fl5«L 3BHS3S&1 ®Bpi9 Absolute Dominorrt Indicator SssTWS^Stnsjjini (Pi a. gc^tt^ •Total Covet I'M. Hem Stratum (Plot aire:. 3 m (Afflt Prevalence Index worksheet: ToMft ftHHT of. WtfMvyr-OBl spades FACWspedn . FACs FACUsi UPts Column Totals; . x1 * >2-x3»_ **' . «S" . . (A) . Prevalence Index » bvA • . Hydrophyth: Vegetation Indicators: OomtnsfioeTeells>t30% Prevalence Indexis S3 01 M«|)tic4ogresl Adaptations' (Provide supporting data in Remertts or on a separate sheet) _ VVetlsrid Nonvascular Plants' Problematic Hydrophyte Vsgetaaon' (Explain) ^cscetors of hydric soil and wetland hydtafer# must be present, unless disturbed or problematic. V»fl9frVinpata|unt (Ptotsue:. % Bars Ground In Herb Stratum ^ US Army Corps of Engineers Western Mountetns. VaKeys. and Coast - Interim Version SOIL Sampling Point: PToflHi Description- (Pescrtbe to the depth needed to document the IrioHcatc^w confirm the absence of indicators.) Depth Mjife frerteFam'W. Itnchasi Ctforlmgjstl . Type' „\JK. Temwt Remark; sow V/^T 'Type: C^ortcenlnrtiqn, l>Depletroa PJJ ^Location: PL-Pore Union. M»Matrtt. Hydric Son Irxticstors: (AppScable to all LRRs, unless othsrwtst noted.) Hstoeol (At) _ Hls1iceplpst)0fi(A2) Star* HUSc (A3) Hydrogen SuMd*(M) Depl»lerjBeio«C»rt Surface (A11) Th** Dattt Surface (A12) Sandy Mucky Mmerai (S1) _ StnXfyGejyedMetofS^ Sandy Redox (S5) _ Stripped Matrix (So) Loamy Mucky Mineral (F1) (sxcspt MLRA 1) UxmiyGkiyed Matrix (F2) DspleWd Matrix (F3) Redox Dark. Surface (F0) Depleted Dark Surface (FT) Redox Depressions (F8) Indicators tor Problematic Hyetrtc Sous': 2 cm Muck vMO) Red Parent Materiel (TF2) „ Other (Explain in Remarks) "WScators of hydtapbyttc vegetation and wetland hydrology must ba present, unless drsturted or preblamabc. Restrictive Layer (If present): Type: Depth (Inches):. II Present? Yes. HYDROLOGY °1mifT'nlf^i(iTitfrlinmo'vn^ tr»ffr tflh¥'i"i'¥ Surface Water (A1) High. Water Table (A2) Saturation (A3) Water Marks <B1> _ Sediment Deposes (B2) Drift Deposit" (69) AJgM MM or Crust (84) lK»t Deposits (Bfi) Surface Soil Cracks (86) intatrtation Visible on Aerial ttltaoary (87) . Watar-Stalned Leaves [B91 (except MLRA 1.2,4A,and4B) . SsBCnjst(BH) . Aquatic rnvertebrates (813) . Hydrogen Sulfide Odor (CI) . Oxidized fti&Kpneres along Lrving Roots (C3) . Presence tfRerJticsd Iron (Cn) . Recent Iron Reduata m Tilled Soils (C8) . Slunted 01 Stressed PtontsfDl) (LRR A) . Other (explain » Remarks) Seoondarv Inacaaxs (2 or mora raoutaal WaMr-Stamad Leaves (B9) (MLRA 1.3, <A. and <B) Drainage Patterns (810) Dry-Season Walrn Table (C2) Sawrsbwr visible on Aerial Imagery (C«) Geomorphic Position (D2) Shs»c«Agu«ard(D3) _ FAr^Neutral Test (D5) Raised Ant Mounds (06) (LRR A) Frost-Heave Hurnmocfce (07) Field Obssrvations: Surface Water Present? Yes No _^epm fitches) Water Table Present? Yes No _^JBapth (inches) Saturation Pr»s«nt7 Yes Ho Depth (inches) includes catxlarv trtwa) Wetland Hydrology Praeent7 Yax Mo fteseilbe P^KunMrMa(streani gauge, morti^^ rt available: US Army Corps of Engineers Western Mountains, Vatteys, and Coast - Interim Version 128 of 628 Wetland name or number RATING SUMMARY - Western Washington Name of wetland (or ID «): ^ *"•«»».«. * ' ' fa JPate of site visit: _V_? ^ " Ce^- Jj Trained by Ecology?^Yes ing T~'t 11 ^Wetland has multiple HGM classes?. Rated by C<^- JJ Trained by Ecology ?-^Yes No Date of training, HGM Class used for rating T^e p > ^Wetland has multiple HGM classes? NOTE: Form is not complete without the figures requested (figures can be combined). Source of base aerial photo/map OVERALL WETLAND CATEGORY i-T. (based on functionsj^orspecial characteristics ) 1. Category of wetland based on FUNCTIONS Category I - Total score = 23-27 Category II - Total score =20-22 Category III - Total score =16-19 Category IV - Total score = 9-15 FUNCTION Improving Water Quality Hydrotoglc Habitat Grde the appropriate ratinfis Site Potential H » &>.K Landscape Potential H Q&J L H M(X) Value 3) M L H L H M L,'' TOTAL Score Based on Ratings u I; . 0 2. Category based on SPECIAL CHARACTERISTICS of wetland Score for each function based on three ratings (order of ratings is not important) 9 = H,H,H 8=H,H,M H,H,L H,M,M H,M,L M,M,M H,L,L M,M,L M,L,L L,L,L CHARACTERISTIC CATEGORY Estuarine I II Wetland of High Conservation Value 1 Bog 1 Mature Forest 1 Old Growth Forest 1 Coastal Lagoon i II Interdunal i ii III jy' None of the above Wetland Rating System for Western WA: 2014 Update Rating Form - Effective (anuary 1,2015 1 Wetland name or number Maps and figures required to answer questions correctly for Western Washington Depressional Wetlands Map of: To answer questions: Figures Cowardin plant classes D 1.3, H 1.1, H 1.4 Hydroperiods D 1.4, H 1.2 Location of outlet {can be added to map of hydroperiods) D 1.1, D 4.1 Boundary of area within ISO ft of the wetland (can be added to another figure) D 2.2, D 5.2 Map of the contributing basin D4.3, D5.3 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin {from Ecology website} D 3.1, D 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) D3.3 Riverine Wetlands Map of: To answer questions: Figure t Cowardin plant classes H 1.1, H 1.4 Hydroperiods H1.2 Ponded depressions Rl.l Boundary of area within 150 ft of the wetland (can be added to another figure} R2.4 Plant cover of trees, shrubs, and herbaceous plants R 1.2, R 4.2 Width of unit vs. width of stream (can be added to another figure) R4.1 Map of the contributing basin R 2.2, R 2.3, R 5.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) R3.1 Screen capture of list of TMDLs for WRIA in which unit is found (from web) R 3.2, R 3.3 Lake Frinee Wetlands Map of: To answer questions: Figure* Cowardin plant classes Ll.l, L4.1, H1.1.H1.4 Plant cover of trees, shrubs, and herbaceous plants L1.2 Boundary of area within 150 ft of the wetland (can be added to another figure) L2.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) L 3.1, L 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) L3.3 Slope Wetlands Map of: ' To answer questions: Figure* Cowardin plant classes H 1.1, H 1.4 Hydroperiods H1.2 Plant cover of dense trees, shrubs, and herbaceous plants S1.3 Plant cover of dense, rigid trees, shrubs, and herbaceous plants (con be added to figure above) S4.1 Boundary of 150 ft buffer (can be added to another figure) S 2.1, S 5.1 1 km Polygon: Area that extends 1 km from entire wetland edge - Including polygons for accessible habitat and undisturbed habitat H2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) S 3.1, S 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) S3.3 Wetland Rating System for Western WA: 2014- Update Rating Form - Effective January 1,2015 2 129 of 628 Wetland name or number HGM Classification of Wetlands in Western Washington For questions 1-7, the criteria described must apply to the entire unit being rated. If the hydrologic criteria listed in each question do not apply to the entire unit being rated, you probably have a unit with multiple HGM classes. In this case, identify which hydrologic criteria in questions 1-7 apply, and go to Question 8. 1. Are the water levels in the entire unit usually controlled by tides except during floods? , NO-goJs^ YES-the wetland class is Tidal Fringe-go to 1.1 1.1 Is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? NO - Saltwater Tidal Fringe (Estuarine) YES - Freshwater Tidal Fringe If your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. If it is Saltwater Tidal Fringe it is an Estuarine wetland and is not scored. This method cannot be used to score functions for estuarine wetlands. 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. Groundwater and surface water runoff are NOT sources of water to the unit. NO-go to3 YES-The wetland class is Flats If your wetland can be classified as a Flats wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet all of the following criteria? The vegetated part of the wetland is on the shores of a body of permanent open water (without any plants on the surface at any time of the year) at least 20 ac (8 ha) in size; _At least 30% of the open water area is deeper than 6.6 ft (2 m). NO - go to 4 YES - The wetland class is Lake Fringe (Lacustrine Fringe) 4. Does the entire wetland unit meet all of the following criteria? _The wetland is on a slope [slope can be very gradual), The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without distinct banks, The water leaves the wetland without being impounded. NO - go to 5 YES - The wetland class is Slope NOTE: Surface water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <3 ft diameter and less than 1 ft deep). 5. Does the entire wetland unit meet all of the following criteria? The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river, The overbank flooding occurs at least once every 2 years. Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,201S 3 Wetland name or number NO - go to 6 YES - The wedand class is Riverine NOTE: The Riverine unit can contain depressions that are filled with water when the river is not flooding 6. Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year? 77i/s means that any outlet, if present, is higher than the interior of the wetland. NO - go to 7 YES - The wedand class is Depressi^naT^^*^ 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding? The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. NO - go to 8 YES - The wetland class is Depressional 8. Your wedand unit seems to be difficult to classify and probably contains several different HGM classes. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a Depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN TH E UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within the wetland unit being scored. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the HGM class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. HGM classes within the wetland unit being rated HGM class to use in rating Slope + Riverine Riverine Slope + Depressional Depressional Slope + Lake Fringe Lake Fringe Depressional + Riverine along stream within boundary of depression Depressional Depressional + Lake Fringe Depressional Riverine + Lake Fringe Riverine Salt Water Tidal Fringe and any other class of freshwater wetland Treat as ESTUARINE If you are still unable to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 4 130 of 628 Wetland name or number DEPRESSIONAL AND FLATS WETLANDS Water Quality Functions - Indicators that the site functions to improve water quality D 1.0. Does the site have the potential to improve water quality? D 1.1. Characteristics of surface water outflows from the wetland: Wetland is a depression or flat depression (QUESTION 7 on key) with no surface water leaving it (no outlet). points = 3 Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outlet. "CjointsfJV Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing points = 1 Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch. points = 1 D 1.1. Characteristics of surface water outflows from the wetland: Wetland is a depression or flat depression (QUESTION 7 on key) with no surface water leaving it (no outlet). points = 3 Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outlet. "CjointsfJV Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing points = 1 Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch. points = 1 D 1.2. Uje. soil 2 in below the surface (or duff laverl is true day or true organic (use NRCS definitionsj.tes = 4 No = 0 0 1.3. Characteristics and distribution of oersistent olants (Emereent. Scrub-shrub, and/or Forested Cowardin classes): Wetland has persistent, ungraded, plants > 95% of area ,^points=>> Wetland has persistent, ungrazed, plants > K of area points = 3 Wetland has persistent, ungrazed plants > Vio of area points = 1 Wetland has persistent, ungrazed plants < Vio of area points = 0 <• D 1.4. Characteristics of seasonal Dondine or inundation: This is the area that is ponded for at teast 2 months. See description in manual. Area seasonally ponded is > S4 total area of wetland points = JL.J, Area seasonally ponded is > % total area of wetland points = 2 Area seasonally ponded is < K total area of wetland points = 0 U Total for D1 f Add the points in the boxes above n Rating of Site Potential If score is: 12-16 = H J^6-11 = M 0-5 = 1 Record the rating on the first page D 2.0. Does the landscape have the potential to support the water quality function of the site? _ D 2.1. Does the wetland unit receive stormwater discharges? Yes = l llg = 0 ^ 01.1. Is> 10% of the area within 150 ft of the wetland in land uses that generate pollutants? Yes = 1 /NO = Q3 a D 2.3. Are there septic systems within 250 ft of the wetland? C Yes =J3»o = 0 ' D 2.4. Are there other sources of pollutants coming into the wetland that are not listed in questions D 2.1-D 2.3? Source Yes^i"~No3S^ c) Total for D 2 y Add the points in the boxes above \ Rating of Landscape Potential If score is: 3or4 = H ^ lor2 ~ M 0=1 Record the rating on the first page 0 3.0. Is the water quality improvement provided by the site valuable to society? D 3.1. Does the wetland discharge directly (i.e., within 1 mi) to a stream, river, lake, or marine water tljaUilin the 303(d) list? .'Yes-1J*>-0 » D 3.2. Is the wetland in a basin or sub-basin where an aquatic resource is on the 303(d) list? ^ Yes =d»o = 0 ! D 3.3. Has the site been identified in a watershed or local plan as important for maintaining water quaJity_(onswer YES if there is a TMDLfor the basin in which the unit is found)? (Yes=jj»ik> = 0 Total for D 3 Add the points in the boxes above Rating of Value If score is: 2-4 -H 1 = M 0 = L Record the rating on the first page Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 5 Wetland name or number. A-DEPRESSIONAL AND FLATS WETLANDS Hydrologic Functions - Indicators that the site functions to reduce flooding and stream degradation D 4.0. Does the site have the potential to reduce flooding and erosion? D 4.1. Characteristics of surface water outflows from the wetland: Wetland is a depression or flat depression with no surface water leaving it (no outlet) points = 4 Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outletpoinf^2] Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch points = 1 Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing points = 0 D 4.2. Deoth of storace durins wet periods: Estimate the heiaht ofoondina above the bottom of the outlet. For wetlands with no outtet, measure from the surface of permanent water or if dry, the deepest part. Marks of ponding are 3 ft or more above the surface or bottom of outlet points = 7 Marks of ponding between 2 ft to < 3 ft from surface or bottom of outlet points = 5 Marks are at least 0.5 ft to < 2 ft from surface or bottom of outlet tfoTnts^3 ^> The wetland is a "headwater" wetland paints = 3 Wetland is flat but has small depressions on the surface that trap water points = 1 Marks of ponding less than 0.5 ft (6 in) points = 0 3 D 4.3. Contribution of the wetland to storaae in the watershed: Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itself. The area of the basin is less than 10 times the area of the unit pqinls The area of the basin is 10 to 100 times the area of the unit (points =£/ The area of the basin is more than 100 times the area of the unit points = 0 Entire wetland is in the Flats class points = 5 Total for D 4 ^ Add the points in the boxes above Rating of Site Potential If score is: 12-16 = H S5-11 = M 0-5 = 1. Record the rating on the first page D 5.0. Does the landscape have the potential to support hydrologic functions of the site? D 5.1. Does the wetland receive stormwater discharges? Yes = lCNo = Qj? D5.2.ls >10% of the area within 150 ft of the wetland in land uses that generate excess runoff? Yes = 1 (j4p=j££<'** D 5.3. Is more than 25% of the contributing basin of the wetland covered with intensive human land uses (residential at >1 residence/ac, urban, commercial, agriculture, etc.)? Yes = 1 fNo=j£2** Total for D 5 Add the points in the boxes above o Rating of Landscape Potential If score is: 3 = H lor2 = M Record the rating on the first page D 6.0, Are the hydrologic functions provided by the site valuable to society? D 6.1. The unit is in a landscape that has flooding problems. Choose the description that best matches conditions around the wetland unit being rated. Do not add points. Choose the tjiahest score if mqre than one condition is met. The wetland captures surface water that would otherwise flow down-gradient into areas where flooding has damaged human or natural resources (e.g., houses or salmon redds): • Flooding occurs in a sub-basin that is immediately down-gradient of unit. points = 2 • Surface flooding problems are in a sub-basin farther down-gradient. points = 1 Flooding from groundwater is an issue in the sub-basin. !- POint:^,=^^> The existing or potential outflow from the wetland is so constrained by human or natural conditions that the water stored by the wetland cannot reach areas that flood. Explain why t points = 0 There are no problems with flooding downstream of the wetland. points = 0 D 6.2. Has the site been identified as important for flood storage or flood conveyance in a regional flood control plan? Yes=2 No = 0 Total for D 6 Add the points in the boxes above Ratingof Value If scoreis: 2-4 = H **1 = M 0 = L Record the rating on the first page Wedand Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 6 131 of 628 Wetland name or number These questions apply to wetlands of all HGM classes. HABITAT FUNCTIONS - Indicators that site functions to provide important habitat H 1.0. Does the site have the potential to provide habitat? H 1.1. Structure of plant community: Indicators are Cowardin classes and strata within the Forested class. Check the Cowardin plant classes in the wetland. Up to 10 patches may be combined for each class to meet the threshold of% oc or more than 10% of the unit if it is smaller than 2.5 ac. Add die number of structures checked. Aquatic bed 4 structures or more: points = 4 Emergent 3 structures: points = 2 Sprifcshrub {areas where shrubs have > 30% cover) 2 structures: points = 1 fr^orested (areas where trees have > 30% cover) 1 structure: ^rfcjj^ If the unit has a Forested class, check if: The Forested class has 3 out of 5 strata (canopy, sub-canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the Forested polygon H 1.2. Hydroperiods Check the types of water regimes (hydroperiods) present within the wetland. The water regime has to cover more than 10% of the wetland or % ac to count (see text for descriptions of hydroperiods). Perasanently flooded or inundated 4 or more types present: points = 3 ^Seasonally flooded or inundated 3 types present: points = 2 Occasionally flooded or inundated 2 types present: points = 1 Saturated only 1 type pr^ntT points - (T^ Permanently flowing stream or river in, or adjacent to, the wetland «-«...-.«-..-••«-•-<-Seasonally flowing stream in, or adjacent to, the wetland take Fringe wetland 2 points Freshwater tidal wetland 2 points H 1.3. Richness of plant species Count the number of plant species in the wetland that cover at least 10 ft2. Different patches of the same species can be combined to meet the size threshold and you do not have to name the species. Do not include Eurasian milfoil, reed canarygrass, purple loosestrife, Canadian thistle If you counted: > 19 species points = 2 5 -19 species vpoinj^^l^ < 5 species points = 0 I H 1.4. Interspersion of habitats Decide from the diagrams below whether interspersion among Cowardin plants classes (described in H 1.1), or the classes and unvegetated areas (can include open water or mudflats) is high, moderate, low, or none. If you have four or more plant classes or three classes and open water, the rating is always high. o CE> <S><&> ( None = 0 pojnjj^ Low = 1 point Moderate = 2 points All three diagrams /yffe tafjA M\ ^HEL 1 1^ 'j in ,his row \ Wy V J ^t^^m&y are HIGH = 3points N. ^/ H S Wedand Rating System fof Western WA: 2014 Update Rating Form - Effective Januaiy 1,2015 13 Wetland name or number H 1.5. Special habitat features: Ched^ne habitat features that are present in the wetland. The number of checks is the number of points. ^ Large, downed, woody debris within the wetland (> 4 in diameter and 6 ft long). Standing snags (dbh > 4 in) within the wetland Undercut banks are present for at least 6.6 ft (2 m) and/or overhanging plants extends at least 3.3 ft (1 m) over a stream (or ditch) in, or contiguous with the wetland, for at least 33 ft (10 m) Stable steep banks of fine material that might be used by beaver or muskrat for denning (> 30 degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet weathered where wood is exposed) Atteast % ac of thin-stemmed persistent plants or woody branches are present in areas that are ^^Jermanentty or seasonally inundated (structures for egg-laying by amphibians) Invasive plants cover less than 25% of the wetland area in every stratum of plants [see H 1.1 for list of strata) *T3^ Total for H 1 ^? Add the points in the boxes above 3 Rating of Site Potential If score is: 15-18 =H 7-14= M ^0-6 = L Record the rating on the first page H 2.0. Does the landscape have the potential to support the habitat functions of the site? H 2.1. Accessible habitat (indude only habitat thatdirecdy abuts wetland unit). ^ Calculate: ^ % undisturbed habitat f®+ f(% moderate and low intensity land uses)/21 = ^ % If total accessible habitat is: > Vs (33.3%) of 1 km Polygon points = 3 20-33% of 1 km Polygon P°|0ts =.2 10-19% of 1 km Polygon v pojnte =JL^, < 10% of 1 km Polygon points » 0 ' \ H 2.2. Undisturbed habitat in 1 km Polygon around the wetland. m . „„ Calculate: % undisturbed habitat*** + RK moderate and tow intensity land uses)/21 * « -? : % Undisturbed habitat > 50% of Polygon points = 3 Undisturbed habitat 10-50% and in l-3patches point5.= 2i Undisturbed habitat 10-50% and > 3 patches K points = 1^ Undisturbed habitat < 10% of 1 km Polygon points = 0 ! H 2.3. Land use intensity in 1 km Polygon: If > 50% of 1 km Polygon is high intensity land use points = (- 2) £ 50% of 1 km Polygon is high intensity r points = 0'? Total for H 2 ^ Add the points in the boxes above Rating of Landscape Potential tf score is: 4-6 = H ^-3 * M < 1 = L Record the rating on the first page H 3.0. Is the habitat provided by the site valuable to society? H 3.1. Does the site provide habitat for species valued in laws, regulations, or policies? Choose only the highest score that applies to the wetland being rated. Site meets ANY of the following criteria: points = 2 — It has 3 or more priority habitats within 100 m (see next page} — It provides habitat for Threatened or Endangered species (any plant or animal on the state or federal lists) — it is mapped as a location for an individual WDFW priority species — It is a Wetland of High Conservation Value as determined by the Department of Natural Resources — It has been categorized as an important habitat site in a local or regional comprehensive plan, in a Shoreline Master Plan, or in a watershed plan Site has 1 or 2 priority habitats (listed on next page) within 100 m points = 1 Site does not meet anv of the criteria above ^ r, points = 0. ' ,.s* Rating of Value If score is: 2 = H 1 = M _£jO = L Record the rating on the first page Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 14 132 of 628 Wetland name or number WDFW Priority Habitats Priority habitats listed by WDFW (see complete descriptions of WDFW priority habitats, and the counties in which they can be found, in: Washington Department of Fish and Wildlife. 2008. Priority Habitat and Species List. Olympia, Washington, 1^7 pp, http://wdfw.wa.gov/p.uhIj.cff^ or access the list from here: hUp;//yvrifWiWfl,soy/cpnserYaUon/ph.Vli.>t/3 Count how many of the following priority habitats are wfthin 330 ft (100 m) of the wetland unit: NOTE: This question is independent of the land use between the wetland unit and the priority habitat — Aspen Stands: Pure or mixed stands of aspen greater than 1 ac (0.4 ha). — Biodiversity Areas and Corridors: Areas of habitat that are relatively important to various species of native fish and wildlife {full descriptions in WDFWPHSreport). — Herbaceous Balds: Variable size patches of grass and forbs on shallow soils over bedrock. — Old-growth/Mature forests: Qld-firflwfo west of Cascade crest - Stands of at least 2 tree species, forming a multi-layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha} > 32 in (81 cm) dbh or > 200 years of age. Mature forests - Stands with average diameters exceeding 21 in (53 cm) dbh; crown cover may be less than 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth; 80-200 years old west of the Cascade crest — Oregon White Oak; Woodland stands of pure oak or oak/conifer associations where canopy coverage of the oak component is important [full descriptions In WDFW PHS report p. 158 - see web link above). — Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. — Westside Prairies: Herbaceous, non-forested plant communities that can either take the form of a dry prairie or a wet prairie {full descriptions in WDFW PHS report p. 161 - see web link above). — Instream: The combination of physical, biological, and chemical processes and conditions that interact to provide functional life history requirements for instream fish and wildlife resources. — Nearshore: Relatively undisturbed nearshorehabitats, These include Coastal Nearshore, Open Coast Nearshore, and Puget Sound Nearshore. (full descriptions of habitats and the definition of relatively undisturbed are in WDFW report -see web link on previous page). — Caves; A naturally occurring cavity, recess, void, or system of interconnected passages under the earth in soils, rock, ice, or other geological formations and is large enough to contain a human. — Cliffs: Greater than 25 ft (7.6 m) high and occurring below 5000 ft elevation. — Talus: Homogenous areas of rock rubble ranging in average size 0.5 - 6.5 ft (0.15 - 2.0 m), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. — Snags and Logs: Trees are considered snags if they are dead or dying and exhibit sufficient decay characteristics to enable cavity excavation/use by wildlife. Priority snags have a diameter at breast height of > 20 in (51 cm) in western Washington and are > 6.5 ft (2 m) in height Priority logs are > 12 in (30 cm) in diameter at the largest end, and > 20 ft (6 m) long. Note: All vegetated wetlands are by definition a priority habitat but are not included in this list because they are addressed elsewhere. Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 15 Wetland name or number CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Wetland Type Check off any criteria that apply to the wedand. Grcle the category when the appropriate criteria are met. Category SC 1.0. Estuarine wetlands Does the wetland meet the following criteria for Estuarine wetlands? — The dominant water regime is tidal, — Vegetated, and — With a salinity greater than 0.5 ppt Yes -Go to SC 1.1 <1$o= Not an estuarine wetland^ SC 1.1. Is the wetland within a National Wildlife Refuge, National Park, National c^"^^^^ Nnturiil ^r~r Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? Yes - Category 1 No - Go to SC 1.2 Cat 1 SC 1.2. Is the wetland unit at least 1 ac in size and meets at least two of the following three conditions? —The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than 10% cover of non-native plant species. (If non-native species are Spartkia, see page 25) —At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. —The wetland has at least two of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. Yes = Category 1 No = Category II Cat. 1 Cat II SC2.0. Wetlands of High Conservation Value (WHCV) SC 2.1. Has the WA Department of Natural Resources updated their website to include the list of Wetlands of High Conservation Value? Yes - Go to SC 2.2 'fi^Go^SXil* SC 2.2. Is the wetland listed on the WDNR database as a Wetland of High Conservation Value? Yes = Category 1 No = Not a WHCV SC 2.3. Is the wetland in a Section/Township/Range that contains a Natural Heritage wetland? httD://wwwl.dnr.wa.eov/nhD/refdesk/datasearchywnhDwetlands.Ddf ~ ^ Yes -Contact WNHP/WDIMR and go to SC 2.4 V.=$oi = Not a WHCV^ SC 2.4. Has WDNR identified the wetland within the S/T/R as a Wetland of High Conservation Value and listed it on their website? Yes = Category 1 No = Not a WHCV Cat I SC 3.0. Bogs Does the wetland (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below. If you answer YES you will still need to rate the wetland based on Its functions. SC 3.1. Does an area within the wetland unit have organic soil horizons, either peats or mucks, that compose 16 ,ip_ or more of the first 32 in of the soil profile? Yes - Go to SC 3.3\o - Go to SC 3.2\ SC 3.2. Does an area within the wetland unit have organic soils, either peats or mucks, that are lesTfflalflKlna^ep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on top of a Tafceoc^ pond? Yes-Go to SC 3.3 ^lo = !s noXa.bog-SC 3.3. Does an area with peats or mucks have more than 70% cover of mosses at ground level, AND atleast a 30% cover of plant species listed in Table 4? Yes = Is a Category 1 bog No - Go to SC 3.4 NOTE: If you are uncertain about the extent of mosses in the understory, you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16 in deep. If the pH is less than 5.0 and the plant species in Table 4 are present, the wetland is a bog. SC 3.4. Is an area with peats or mucks forested (> 30% cover) with Sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Engelmann spruce, or western white pine, AN D any of the species (or combination of species) listed in Table 4 provide more than 30% of the cover under the canopy? Yes = Is a Category f bog No = Is not a bog Cat 1 Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 16 133 of 628 Wetland name or number SC 4.0. Forested Wetlands Does the wetland have at least 1 contiguous acre of forest that meets one of these criteria for the WA Department of Fish and Wildlife's forests as priority habitats? If you answer YES you will still need to rate the wetland based on Us functions, — Old-growth forests (west of Cascade crest): Stands of at least two tree species, forming a multi-layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 in (81 cm) or more. — Mature forests (west of the Cascade Crest): Stands where the largest trees are 80- 200 years old OR the species that make up the canopy have an average diameter (dbh) exceeding 21 in (53 cm): ~— Yes = Category 1 No = Not a forested wetland for th'nsecS^ Cat 1 SC 5.0. Wetlands In Coastal Lagoons ^» ,»• ^^^"^^ Does the wetland meet all of the following criteria of a wetland in a coastal lagoon? — The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks — The lagoon in which the wetland is located contains ponded water that is saline or brackish (> 0.5-pot) during most of the year in at least a portion of the lagoon (needs to be meesurednear the bottom) Yes -Go to SC 5.1 Uo= Not a wetland in a coastal lagoon SC 5.1. Does the wetland meet all of the following three conditions? ,,,VVJWa.,-»w,-^™..».~.,- - ""' — The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of aggressive, opportunistic plant species (see list of species on p. 100). — At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. —The wetland is larger than Vio ac (4350 ft2) Yes = Category I No = Category II Cat. 1 Cat II SC 6.0. Interdunal Wetlands Is the wetland west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? // you answer yes you wHI still need to rate the wetland based on Its habitat functions. In practical terms that means the following geographic areas: — Long Beach Peninsula: Lands west of SR 103 — Grayfand-Westport: Lands west of SR 105 . .,.^_^jK — Ocean Shores-Copalis: Lands west of SR 115 and SR 109 ^""^ ^ ^ Yes - Go to SC 6.1 No = hot an Interdunal wetland forrjjior^ SC 6.1. Is the wetland 1 ac or larger and scores an 8 or 9 for the habitat functions on the form (rates H,H,H or H,H,M for the three aspects of function)? Yes = Category 1 No - Go to SC 6.2 SC 6.2. Is the wetland 1 ac or larger, or is it in a mosaic of wetlands that is 1 ac or larger? Yes = Category II No-Go to SC 6.3 SC 6.3. Is the unit between 0.1 and 1 ac, or is it in a mosaic of wetlands that is between 0.1 and 1 ac? Yes = Category III No = Category IV Cat) Cat. 1) Cat. Ill Cat. IV Category of wetland based on Special Characteristics If you answered No for all types, enter "Not Applicable" on Summary Form Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 17 134 of 628 135 of 628 136 of 628 137 of 628 October 2, 2018 Revised January 14, 2019 Stowe Construction PO Box 1054 Sumner, Washington 98390 Attn: Mr. Bryan Stowe stowerock@aol.com Revised Preliminary Geotechnical Engineering Report Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, -0320 & 0313 Doc ID: StoweConst.56thAveS.RGu.Rev01 INTRODUCTION This revised prel iminary geotechnical engineering report summarizes our site observations, subsurface explorations, laboratory testing and engineering analyses and provides geotechnical recommendations and design criteria for the proposed residential development to be constructed at 32727 – 56th Avenue South in Auburn, Washington. The site location is shown on the Site Location Map, Figure 1. We previously prepared a draft Geotechnical Engineering Report for two of the above- mentioned parcels (PN: 9262800295, & -0320) dated June 16, 2017. We understand that you are adding an additional parcel (PN: 9262800313) to the development; therefore, City of Auburn is requiring a Geotechnical Engineering Report be prepared to satisfy City of Auburn Critical Areas Ordinances, and Development Codes. Changes to the original report text are presented in bold and italicized text. Our understanding of the project is based on our correspondence with Mr. Bryan Stowe of Stowe Construction, our review of the conceptual Site Plan prepared by Barghausen Consulting Engineering, Inc. dated January 27, 2017, our review of the Preliminary Road and Drainage Plan prepared by Barghausen Consulting Engineering, Inc. dated January 11, 2019, our previous May 16, 2007 site visit and subsurface explorations, our recent September 25, 2018 site visit and subsurface explorations, our understanding of the City of Auburn Critical Areas Ordinances, and Development Codes, our understanding of the 2012 Department of Ecology Stormwater Management Manual for Western Washington (SWMMWW), with the 2014 amendments, and our experience in the area. The site consist of a three tax parcels located west of the intersection of 56th Avenue South and South 328th Street. The northern parcel (PN: 9262800295) and the southern parcels (PN: 9262800320 & 9262800313) are separated by the South 328th Street Right-Of-Way. The northern parcel is developed with a shop. We understand that you propose to construct 44 single family residences, several paved access tracts, and associated utilities on the above mentioned parcels. We further understand that you propose to construct a drainage facility at Tract A, in the southern portion 138 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 2 of the site. We anticipate that the new residences will be a one or two-story, wood-framed structures likely founded on conventional shallow foundations. We anticipate the residences on lots 30 through 43 will likely have a daylight basement configuration, while the residences on the other lots will likely have a crawl space under the living area and slab-on-grade floors under the garages. SCOPE The purpose of our services is to evaluate the surface and subsurface conditions at the site as a basis for addressing City of Auburn requirements as well as addressing the potential of the site soils for supporting foundation loads. We have also included geotechnical recommendations for the project. Specifically, the scope of services for this project will include the following: 1. Reviewing existing geological, hydrogeological, and geotechnical literature for the site area; 2. Exploring the subsurface conditions by performing a geotechnical reconnaissance; 3. Exploration subsurface conditions across the site by excavating 6 additional test pits in the additional parcel at select locations; 4. Collect select soil samples from the explorations and conduct 3 grain size analyses; 5. Describing surface and subsurface conditions, including soil type, depth to groundwater, and estimate of high groundwater; 6. Addressing the appropriate criteria for Geologic Hazards per the current City of Auburn Critical Areas Ordinance; 7. Providing geotechnical conclusions and recommendations regarding seismic site class and design coefficients, seismic hazard analysis, site grading activities including; site preparation, subgrade preparation, fill placement criteria, suitability of on-site soils for use as structural fill, temporary and permanent cut and fill slopes, drainage and erosion control measures; 8. Providing conclusions regarding foundations, including shallow conventional footings, along with floor slab support and design criteria, including bearing capacity and subgrade modulus if appropriate; 9. Providing our opinion about the feasibility of onsite infiltration in accordance with the 2012 SWMMWW, including a preliminary design infiltration rate based on grain size data, as appropriate, to meet the Soils Report requirement of the 2012 SWMMWW; 10. Performing 2 small scale Pilot Infiltration Test (PIT) in accordance with the 2012 SWMMWW, Volume III, Section 3.3.6, if infiltration appeared to be feasible; 11. Providing recommendations for erosion and sediment control during wet weather grading and construction; and 12. Preparing a written Geotechnical Engineering Report with design recommendations summarizing our site observations and conclusions, and our geotechnical recommendations and design criteria, along with the supporting data. The above scope of work was summarized in our Proposal for Geotechnical Engineering Services dated September 21, 2018. We received authorization to proceed from you on September 25, 2018. 139 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 3 SITE CONDITIONS Surface Conditions The site is located at 32727 – 56th Avenue South, Auburn, Washington, within an area of existing residential development in the Auburn uplands. According to the information obtained from the King County iMap website, the site encompasses three tax parcels east of the intersection of 56th Avenue South and South 328th Street. The northern parcel (PN: 9262800295) is generally rectangular in shape, the southeastern parcel (PN: 9262800320) is a L-shaped parcel, and the southwestern parcel (PN: 9262800313) is a mirrored C-shaped parcel. Each parcel measures approximately 300 feet wide (north to south) by approximately 620 feet deep (east to west). The three tax parcels, when combined, encompass approximately 10.23 acres. The site is bounded by 56th Avenue South to the east, by 51st Avenue South to the west, by an undeveloped parcel and existing residential development to the north, and by existing residential development to the south. The northern parcel is currently developed with a shop, while the southern parcels are undeveloped. The northern parcel and the southern parcels are separated by the South 328th Street Right-Of-Way. According to the information obtained from the King County iMap website, the northern parcel generally slopes down from 56th Avenue South to the west at approximately 8 to 15 percent. The upper portion of the northern parcel is generally flat before the parcel slopes down to the west at about 8 to 15 percent. The lower portion of the northern parcel consists of a gently slope drainage that slopes down to the south. The drainage continues onto the southeastern parcel and slopes down to the south at approximately 5 to 10 percent. The southeastern parcel slopes up to the northeast towards 56th Avenue South at about 15 to 20 percent. The southwestern parcel generally slopes down to the south and the west. The upper portion of the southwestern parcel generally slopes down to the south at approximately 8 to 15 percent. The western portion of this parcel generally slopes down to the west at approximately 12 to 18 percent. The total topographic relief across the site is on the order of 50 to 55 feet. The existing site configuration and conditions are shown on the attached Site Vicinity Map, included as Figure 2a. Vegetation in the undeveloped portions of the site generally consist of a moderate stand of a mixture of deciduous and coniferous trees with a moderate understory of native and invasive plants and shrubs. Vegetation in the drainage channel areas generally consist of a moderate stand understory of native and invasive plants and shrubs. No evidence of standing water, seeps, or springs was observed at the site at the time of our site visit. Site Soils The National Resource Conservation Service (NRCS) Web Soil Survey maps the site as being underlain by Alderwood gravelly sandy loam (AgC) soils. The Alderwood soils are derived from glacial till, form on slopes of 8 to 15 percent, are listed as having a “moderate” erosion hazard when exposed, and are included in hydrologic soils group B. A copy of the NRCS soils map for the site vicinity is attached as Figure 3. Site Geology The Geologic Map of the Poverty Bay 7.5-minute Quadrangle, Washington by Derek B. Booth, Howard H. Waldron, and Kathy G. Troost (2003) maps the site as being underlain by glacial till (Qvt). These glacial soils were deposited during the most recent Vashon Stade of the Fraser Glaciation, 12,000 to 15,000 years ago. The glacial till consists of a heterogeneous mixture of gravel, sand, silt, and clay that was deposited at the base of the continental ice mass and subsequently overridden. As 140 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 4 such, this geologic unit is considered over-consolidated and provides high strength, low compressibility and low porosity and permeability characteristics where undisturbed. No landslides or landslide deposits are mapped within 300 feet of the site. No evidence of soil movement was reported or observed at the site at the time of our site visit. No areas of landslides or mass wasting are mapped at or near the site. An excerpt of the referenced geologic map is included as Figure 4. Subsurface Explorations On May 16, 2017, a field representative from GeoResources, LLC (GeoResources) visited the site and monitored the excavation of 7 test pits to depths of about 3 to 10½ feet below the existing ground surface as part of the draft Geotechnical Engineering Report, dated June 16, 2017. On September 25, 2018, a field representative from GeoResources returned to the site and monitored the excavation of 6 additional test pits to depths of about 4½ to 5½ feet below the existing ground surface, logged the subsurface conditions encountered in each test pit, and obtained representative soil samples. The test pits were excavated by a medium track-mounted excavator operated by you. The specific number, locations, and depths of our explorations were selected based on the configuration of the proposed development and were adjusted in the field based on consideration for underground utilities, existing site conditions, site access limitations and encountered stratigraphy. Representative soil samples obtained from the test pits were placed in sealed plastic bags and then taken to a laboratory for further examination and testing as deemed necessary. The test pits were then backfilled with the excavated soils and bucket tamped, but not otherwise compacted. Table 1, below, summarizes the approximate functional locations, surface elevations, and termination depths of our subsurface explorations. TABLE 1: APPROXIMATE LOCATIONS, ELEVATIONS, AND DEPTHS OF EXPLORATIONS Test Pit Number Functional Location Surface Elevation1 (feet) Termination Depth (feet) Termination Elevation1 (feet) TP-1 TP-2 TP-3 TP-4 TP-5 TP-6 TP-7 N-central portion of parcel 9262800295 NW corner of parcel 9262800295 SW corner of parcel 9262800295 S-central portion of parcel 9262800320 Central portion of parcel 9262800320 N-central portion of parcel 9262800320 NE corner of parcel 9262800295 414 415 414 402 415 408 427 3 9 4½ 8¾ 10½ 8 5 411 406 409½ 393¼ 404½ 400 422 TP-101 TP-102 TP-103 TP-104 TP-105 TP-106 NE corner of parcel 9262800295 NW corner of parcel 9262800313 S-central portion of parcel 9262800313 N-central portion of parcel 9262800313 NE corner of parcel 9262800313 SE corner of parcel 9262800313 431 420 419 424 414 414 5 5 4½ 5½ 5½ 5½ 426 415 414½ 418½ 408½ 408½ Notes: 1 = Elevation datum based on King County iMap website 141 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 5 The subsurface explorations excavated as part of this evaluation indicate the subsurface conditions at specific locations only, as actual subsurface conditions can vary across the site. Furthermore, the nature and extent of such variation would not become evident until additional explorations are performed or until construction activities have begun. Based on our experience in the area and extent of prior explorations in the area, it is our opinion that the soils encountered in the explorations are generally representative of the soils at the site. The soils encountered were visually classified in accordance with the Unified Soil Classification System (USCS) and ASTM D: 2488. The USCS is included in Appendix A as Figure A-1. The approximate locations of our test pits are indicated on the attached Site and Exploration Plan, Figure 2 b, while the descriptive logs of our test pits are included in Appendix A as Figures A-2 through A-4. Subsurface Conditions The subsurface conditions encountered in our 2017 explorations were fairly uniform across the site, and generally confirmed the mapped stratigraphy. In general, our test pits encountered about 1 to 8½ feet of dark brown to grey brown topsoil/fill with organics and construction debris. Underlying the surficial soils in test pits TP-1, TP-3, and TP-4, we encountered brown to grey with iron oxide staining/mottling silty sand and gravel in very dense, damp condition that was encountered to the full depth explored. We interpret these soils to be glacial till. Underlying the surficial soils in test pits TP-2, TP-5, and TP-6, we encountered about ½ to 4½ feet of brown to grey with iron oxide staining/mottling sandy silt in a medium dense, damp condition. These soils were encountered to the full depth explored in test pit TP-5. Underlying the silt, we encountered brown to grey silty sand with gravel in a very dense, damp to saturated condition. We interpret these soils to be glacial till. In test pit TP-7, we encountered about 2½ feet of brown silty sand and gravel in a very dense, moist condition mantling grey silty sand with gravel in a dense, moist condition. We interpret these soils to be weathered till over glacial till. Previous subsurface exploration logs and corresponding laboratory test results are included in Appendix C. Our recent test pits encountered fairly uniform subsurface conditions that generally confirmed our previous subsurface explorations and the mapped stratigraphy. In general, our test pits encountered approximately ½ to 1 foot of dark brown topsoil. Underlying the topsoil, test pit TP-101 encountered approximately 1½ feet of brown silty sand with gravel and some to trace organics in a medium dense, moist condition. We interpret these soils to be previously placed, undocumented fill material. Underlying the fill, we encountered approximately 1 foot of dark brown relict topsoil with abundant organics in a loose, saturated condition. The saturated condition is likely the result of the infiltration testing. Underlying the relict topsoil, we encountered approximately 1 foot of reddish brown with iron oxide staining/mottling silty sand with gravel in a loose to medium dense, moist condition mantling brown grey silty sand with gravel in a dense, moist condition that was encountered to the full depth explored. We interpret these deeper soils to be weathered till over glacial till. Underlying the topsoil in test pits TP-103, TP-104, TP-105 and TP-106, we generally encountered approximately 1 to 2 feet of brown with iron oxide staining/mottling silty sand with varying amounts of gravel and occasional boulders in a medium dense, moist condition mantling grey silty sand with varying amounts of gravel in a dense, moist condition that was encountered to the full depth explored. We interpret these soils to be weathered till over glacial till. Underlying the topsoil in test pit TP-102, we encountered approximately 2 feet of brown grey with some iron oxide staining/mottling gravel with silt and sand in a loose to medium dense, moist condition mantling grey silty gravel with sand in a dense, 142 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 6 saturated becomes moist condition that was encountered to the full depth explored. These soils were observed to become less wet at approximately 3½ feet below the existing ground surface. We interpret these soils to be gravelly weathered till over glacial till. The saturated condition is likely the result of the infiltration testing. Table 2, below, summarizes the approximate thicknesses, depths, and elevations of selected soil layers encountered in our previous and recent subsurface explorations. TABLE 2: APPROXIMATE THICKNESS, DEPTHS, AND ELEVATION OF SOIL TYPES ENCOUNTERED IN EXPLORATIONS Test Pit Number Thickness of Topsoil/Fill (feet) Depth to Top of Silt (feet) Depth to Top of Weathered/Glacial Till (feet) Elevation1 to Top of Weathered/Glacial till (feet) TP-1 TP-2 TP-3 TP-4 TP-5 TP-6 TP-7 2 2½ 2½ 8½ 10 6 1 NE 2½ NE NE 10 6 NE 2 7 2.5 8.5 NE 6.5 3.5 412 408 411½ 393½ NE 401½ 423½ TP-101 TP-102 TP-103 TP-104 TP-105 TP-106 3 ¾ 1 1 1 1 NE NE NE NE NE NE 3 ¾ 1 1 1 1 428 419¼ 418 423 413 413 Notes: 1 = Elevation datum based on King County iMap website NE = Not encountered within depth explored Laboratory Testing Geotechnical laboratory tests were performed on select samples retrieved from the test pits to determine soil index and engineering properties encountered. Laboratory testing included visual soil classification per ASTM D: 2488, grain size analyses per ASTM D: 422, modified proctor per ASTM D:1557, and California bearing ratio (CBR) test per ASTM D:1883 standard procedures. The CBR test, and the corresponding grain size analysis and modified proctor were performed by an independent analytical laboratory. The results of the laboratory tests are included in Appendix B, and summarized below in Table 3. 143 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 7 TABLE 3: LABORATORY TEST RESULTS FOR ON-SITE SOILS Soil Type Sample Lab ID Numbe r Gravel Content (percent) Sand Content (percent) Silt/Clay Content (percent) CBR (percent) Glacial Till Glacial Till TP-3, S-2, 4¼’ TP-7, S-1, 2½’ 092686 092687 64.3 55.1 28.3 35.7 7.4 9.2 NT NT Glacial Till Weathered Till Glacial Till Weathered Till TP-102, S-1, 2’ TP-106, S-1, 1-3’ TP-106, S-2, 3-5.5’ TP-106, S-1, 1’ 095623 095633 095634 18L447 63.0 55.9 39.0 25.4 29.9 31.7 36.8 54.1 7.1 12.4 14.2 20.5 NT NT NT 17.7 NT = Not tested Cat-ion exchange capacity (CEC) and organic content testing were also performed by an independent laboratory to evaluate the treatment capacity of the shallow onsite soils for LID methods. The results of the laboratory tests are included in Appendix B. The shallow onsite soils contain a cation exchange capacity (CEC) of 4.8 to 6.5 milliequivalents (meq)/100g per SW846 9081 and an organic content of 2.5 to 2.8 percent per ASTM D 2974-13. Groundwater Conditions No groundwater seepage was observed in our recent test pits at the time of excavation. However, groundwater seepage was observed in our test pits TP-1, TP-2, TP-3, and TP-4 at approximately 2 to 8½ feet below the existing ground surface at the time of excavation in 2017. Mottling was observed in some of our previous test pits at approximately 2½ to 6 feet below the existing ground surface, and mottling was observed in all our recent test pits at approximately 1 to 3 feet below the existing ground surface. Groundwater levels within the Auburn Valley are commonly very shallow, on the order of 5 to 10 feet below the ground surface. Mottling may be indicative of seasonal or fluctuating groundwater surface, often associated with a seasonal perched groundwater table. Perched groundwater develops when the vertical infiltration of precipitation through a more permeable soil, such as weathered till, is slowed at depth by a deeper, less permeable soil type, such as glacial till. We expect that perched groundwater may develop seasonally atop the medium dense to dense till soils in the site area. We anticipate fluctuations in the local groundwater levels will occur in response to precipitation patterns, off-site construction activities, and site utilization. Table 4, below, summarizes our depth to and elevation of groundwater encountered in our test pits. 144 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 8 TABLE 4: APPROXIMATE DEPTHS AND ELEVATIONS OF GROUNDWATER ENCOUNTERED IN EXPLORATIONS Exploration Number Depth to Groundwater (feet) Elevation of Groundwater (feet) Date Observed TP-1 2 412 May 16, 2017 (ATE) TP-2 2 413 May 16, 2017 (ATE) TP-3 2½ 411½ May 16, 2017 (ATE) TP-4 8½ 393½ May 16, 2017 (ATE) 1 = Elevation datum based on King County iMap website ATE = At the time of exploration Infiltration Testing On September 25, 2018, a field representative from GeoResources performed two small scale pilot infiltration testing (PIT) PIT-1 and PIT-2 in the eastern portion of the site and western portion of the site, respectively, in general accordance with the 2012 Department of Ecology Stormwater Management Manual for Western Washington (SWMMWW), Volume III, Section 3.3.6. As stated, we were provided with the conceptual Site Plan prepared by Barghausen Consulting Engineering, Inc. dated January 27, 2017. However, we have not been provided with any Civil/Stormwater Plans at the time of preparing this report or prior to completing the PITs. The specific number, location, and depth of our PITs were adjusted in the field based on consideration for underground utilities, existing site conditions, site access limitations, water access limitations and encountered stratigraphy. The approximate location of the infiltration testing pits are shown on the attached Site and Exploration Plan, Figure 2 b. The infiltration testing pits were excavated by a small track-mounted excavator operated by you. PIT-1 was performed at approximately 1 foot below the existing ground surface in the brown silty sand with gravel in a medium dense, moist condition. PIT- 2 was performed at approximately 2 feet below the existing ground surface in the brown grey gravel with silt and sand in a loose to medium dense, moist condition. The bottom of both infiltration tests PIT-1 and PIT-2 measured approximately 3 feet wide by approximately 4½ feet long. We measured a short term infiltration rate of approximately 1.1 and 15 inches per hour for PIT-1 and PIT-2, respectively. The infiltration pits were overexcavated following the completion of the small infiltration testing. Underlying the infiltration test PIT-1, we encountered approximately 1 foot of the similar silty sand with gravel soils that was generally observed at the bottom of the testing in PIT-1. Underlying the silty sand with gravel soils, we encountered approximately 1 foot of dark brown relict topsoil in a saturated condition. We interpret the upper silty sand with gravel soils to be previously placed, undocumented fill material. Underlying the relict topsoil, we encountered weathered till over glacial till in a medium dense to dense, moist condition that was encountered to the full depth explored. The moist conditions observed in the weathered till and glacial till soils, indicates the water in the infiltration test did not infiltrate into the weathered till and glacial till soils. As stated, we measured a short term infiltration rate of approximately 1.1 inches per hour for PIT-1. However, this measured short term infiltration rate should not be considered or used for any design criteria of 145 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 9 stormwater management facilities because of the presence of undocumented fill material and less permeable layers during the over-excavation at the end of infiltration testing. Underlying the infiltration pit PIT-2, we encountered approximately ½ foot of the similar brown grey gravel with silt and sand in a loose to medium dense, saturated condition mantling grey silty gravel with sand in a dense, saturated condition. These soils become moist condition at approximately 3½ feet below the existing ground surface (approximately 1½ feet below the bottom of the testing in PIT-2) that was encountered to the full depth explored. We measured a short term infiltration rate of approximately 15 inches per hour for PIT-2. The dense nature and the moist condition of the underlying soils, indicates the water in the infiltration pit did not infiltrate into the underlying soils. Therefore, this measured short term infiltration rate should not be considered or used for any design criteria of stormwater management facilities because of the presence of less permeable layers during the over-excavation at the end of infiltration testing. It should be noted that these measured short term infiltration rates only represent the brown silty sand with gravel soils and the brown grey gravel with silt and sand soils in PIT-1 and PIT- 2, respectively, and that specific infiltration rates could not be provided for other portions of the site, because of site access and water access restrictions. Recommendations regarding the stormwater infiltration are discussed and included in the “Stormwater Infiltration” section below. CONCLUSIONS AND RECOMMENDATIONS Based on the results of our data review, site reconnaissance, subsurface exploration program, and the presence of groundwater, without mitigation, a spread footing support directly above the existing soils could result in adverse differential settlement. In order to reduce the potential for adverse post-construction settlement, we therefore recommend that the proposed buildings be supported by conventional spread footings on compacted native soils. The foundation should provide the necessary long-term support for the structure, provided it is properly designed and installed. Pertinent conclusions and geotechnical recommendations regarding the design and construction of the proposed development are presented below. Critical Areas Based on the results of our site reconnaissance, subsurface explorations, and our experience in the area, it is our opinion that the site does not meet the technical criteria of a geologic hazard area. Provided the design criteria listed below are followed, the proposed structure will have no greater seismic risk damage than other appropriately designed structures in the Puget Sound area. Liquefaction Potential The presence of dense granular sand and gravel conditions were assumed to be representative for the site conditions beyond the depths explored. Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength due to an increase in pore water pressure in soils. The increase in pore water pressure is induced by seismic vibrations. Liquefaction mainly affects geologically recent deposits of loose, uniformly graded, fine-grained sands that are below the groundwater table. In our opinion, the soils encountered in the test pits consist of medium dense to dense sands and gravels with varying amounts of silt beneath the groundwater table. In our opinion, the risk of liquefaction-induced settlements in these soils during a seismic 146 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 10 event are low. Provided the design criteria listed below are followed, the proposed structure will have no greater seismic risk damage than other appropriately designed structures in the Puget Sound area. Seismic Site Class Based on our observations and the subsurface units mapped at the site, we interpret the structural site conditions to correspond to a seismic Site Class “D” for the onsite soils in accordance with the 2015 IBC (International Building Code) documents and ASCE 7-10 Chapter 20 Table 20.3-1. For design of seismic structures using the IBC 2015, mapped short-period and 1-second period spectral accelerations, SS and S1, respectively, are required. The U.S. Geological Survey (USGS) completed probabilistic seismic hazard analyses (PSHA) for the entire country in November 1996, which were updated and republished in 2002 and 2008. The PSHA ground motion results can be obtained from the USGS website. The results of the updated USGS PSHA were referenced to determine SS and S1 for this site. The results are summarized in the following table with the relevant parameters necessary for IBC 2015 design. TABLE 5: 2015 IBC PARAMETERS FOR DESIGN OF SEISMIC STRUCTURES Spectral Response Acceleration (SRA) and Site Coefficients Short Period 1 Second Period Mapped SRA Ss = 1.276 S1 = 0.488 Site Coefficients (Site Class D) Fa = 1.0 Fv = 1.512 Maximum Considered Earthquake SRA SMS = 1.276 SM1 = 0.738 Design SRA SDS = 0.850 SD1 = 0.492 Foundation Support Based on the subsurface soil conditions encountered across the site, and the conceptual Site Plan prepared by Barghausen Consulting Engineering, Inc. dated January 27, 2017, we recommend that the structures be supported by conventional spread and column footings. All footings should be founded on the medium dense to dense weathered till or glacial till soils, or on structural fill that extends to suitable native soils. We do not recommend footings be founded on the previously placed, undocumented fill or the shallow loose, weathered soils. The native soils at the base of the excavations should be disturbed as little as possible and should be mechanically compacted to a dense and unyielding condition that should provide adequate support for shallow spread footings. All loose, soft or unsuitable material should be removed or recompacted, as appropriate. If material is over excavated below a footing, it should be replaced with controlled density fill (CDF), structural concrete or suitable structural fill. A rat slab of CDF or clean crushed rock could be placed after excavation to prevent disturbance of the subgrade. A geotechnical expert or representative of GeoResources LLC should observe the foundation subgrade at the time of excavation to determine if suitable bearing surfaces have been prepared. 147 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 11 We recommend a minimum width of 24 inches for isolated footings and at least 18 inches for continuous wall footings. All footing elements should be embedded at least 18 inches below grade for frost protection. Footings founded on the native, compacted weathered till soils or on suitable structural fill that extends down to the suitable native soils can be designed using an allowable soil bearing capacity of 2,500 psf (pounds per square foot) for combined dead and long- term live loads. Footings founded on the deeper, native glacial till soils can be designed using an allowable soil bearing capacity of 3,500 psf for combined dead and long-term live loads. The allowable bearing value may be increased by one-third for transient loads such as those induced by seismic events or wind loads. Lateral loads may be resisted by friction on the base of footings and floor slabs and as passive pressure on the sides of footings. We recommend that an allowable coefficient of friction of 0.35 be used to calculate friction between the concrete and the underlying soil. Passive pressure may be determined using an allowable equivalent fluid density of 350 pcf (pounds per cubic foot). Factors of safety have been applied to these values. We estimate that settlements of footings designed and constructed as recommended will be less than 1-inch, for the anticipated load conditions, with differential settlements between comparably loaded footings of ½-inch or less across a 50–foot span. Most of the settlements should occur essentially as loads are being applied. However, disturbance of the foundation subgrade during construction could result in larger settlements than predicted. We have not been provided with the actual loads to determine what the actual total and differential settlements could be. Floor Slab Support We anticipate that the residences will have slab-on-grade floors under the garage. Slab-on- grade floors, if constructed, should be supported on the native medium dense weathered till soils or on structural fill prepared as described above. Areas of old fill material should be evaluated during grading activity for suitability of structural support. Areas of significant organic debris, fines, or other debris should be removed and replaced with appropriately prepared structural fill. We recommend that floor slabs be directly underlain by a capillary break of a minimum 4- inch thick pea gravel or clean 5/8-inch crushed rock. This layer should be placed and compacted to an unyielding condition and should contain less than 2 percent fines. A synthetic vapor retarder is recommended to control moisture migration through the slabs. This is of particular importance where the foundation elements are underlain by the silty till or lake sediments, or where moisture migration through the slab is an issue, such as where adhesives are used to anchor carpet or tile to the slab. A subgrade modulus of 350 kcf (kips per cubic foot) may be used for floor slab design. We estimate that settlement of the floor slabs designed and constructed as recommended, will be ½- inch or less over a span of 50 feet. Subgrade and Below Grade Walls The lateral pressures acting on subgrade and retaining walls (such as basement walls) will depend upon the nature and density of the soil behind the wall. It is also dependent upon the presence or absence of hydrostatic pressure. If the walls are backfilled with granular well-drained soil, the design active pressure may be taken as 35 pcf (equivalent fluid density). Where the walls are restrained from lateral deformation, we recommend an at-rest equivalent earth pressure of 55 pcf. These design values assume a level backslope and drained conditions as described below. Where 148 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 12 required by code, a seismic surcharge of 10H is recommended for active conditions, calculated using the Mononobe-Okabe method. This surcharge is in addition to the static lateral earth pressure and should be assumed to have resultant at 2/3H, and assumes the wall will be backfilled with adequately compacted structural fill. Adequate drainage behind retaining structures is imperative. Positive drainage which controls the development of hydrostatic pressure can be accomplished by placing a zone of drainage behind the walls. Granular drainage material should contain less than 2 percent fines and at least 30% greater than the No. 4 sieve. A geocomposite drain mat may also be used instead of free draining soils, provided it is installed in accordance with the manufacturer’s instructions. A soil drainage zone should extend horizontally at least 18 inches from the back of the wall. The drainage zone should also extend from the base of the wall to within 1 foot of the top of the wall. The soil drainage zone should be compacted to approximately 90 percent of the MDD (maximum dry density as determined in accordance with ASTM D-1557). Over-compaction should be avoided as this can lead to excessive lateral pressures. A minimum 4-inch diameter perforated, or slotted PVC pipe should be placed in the drainage zone along the base and behind the wall to provide an outlet for accumulated water and direct accumulated water to an appropriate discharge location. We recommend that a nonwoven geotextile filter fabric be placed between the soil drainage material and the remaining wall backfill to reduce silt migration into the drainage zone. The migration of silt into the drainage zone can, with time, reduce the permeability of the granular material. The filter fabric should be placed such that it fully separates the drainage material and the backfill and should be extended over the top of the drainage zone. Lateral loads may be resisted by friction on the base of footings and as passive pressure on the sides of footings and the buried portion of the wall, as described in the “Foundation Support” section. We recommend that an allowable coefficient of friction of 0.35 be used to calculate friction between the concrete and the underlying soil. Passive pressure may be determined using an allowable equivalent fluid density of 350 pcf (pounds per cubic foot). Factors of safety have been applied to these values. Temporary Excavations All job site safety issues and precautions are the responsibility of the contractor. The following cut/fill slope guidelines are provided for planning purposes only. Temporary cut slopes will likely be necessary during grading operations or utility installation. All excavations at the site associated with confined spaces, such as utility trenches and retaining walls, must be completed in accordance with local, state, or federal requirements. Based on current Washington Industrial Safety and Health Act (WISHA) regulations, the fill and the weathered soils encountered on the site would be classified as Type C soils, and the deeper glacial till would be classified as Type A soils. According to WSHA, for temporary excavations of less than 20 feet in depth, the side slopes in Type C soils should be sloped at a maximum inclination of 1½H:1V, and the side slopes in lower Type A soils should be sloped at a maximum inclination of 0.75H:1V. All exposed slope faces should be covered with a durable reinforced plastic membrane during construction to prevent slope raveling and rutting during periods of precipitation. These guidelines assume that all surface loads are kept at a minimum distance of at least one half the depth of the cut away from the top of the slope and that significant seepage is not present on the slope face. Flatter cut slopes will be 149 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 13 necessary where significant raveling or seepage occurs, or if construction materials will be stockpiled along the slope crest. As stated in our preliminary Geotechnical Report, dated January 28, 2007, we recommend the temporary cut slopes be sloped at no steeper than inclination of 2H:1V along the northern and southern property boundaries. Where it is not feasible to slope the site soils back at these inclinations, a retaining structure should be considered. Where retaining structures are greater than 4-feet in height (bottom of footing to top of structure) or have slopes of greater than 15 percent above them, they should be engineered per Washington Administrative Code. This information is provided solely for the benefit of the owner and other design consultants and should not be construed to imply that GeoResources assumes responsibility for job site safety. It is understood that job site safety is the sole responsibility of the project contractor. Site Drainage All ground surfaces, pavements and sidewalks at the site should be sloped away from the structures. The site should also be carefully graded to ensure positive drainage away from all structures and property lines. Surface water runoff should be controlled by a system of curbs, berms, drainage swales, and or catch basins, and conveyed to an appropriate discharge point. We recommend that footing drains are installed for the residence in accordance with IBC 1805.4.2, and basement walls (if utilized) have a wall drain as described above. The roof drain should not be connected to the footing drain. Figure 5 shows typical wall drainage and backfilling details. If the basement cut extends below the adjacent municipal stormwater system, a sump and pump system may be required. Permanent Cut and Fill Slopes We recommend a maximum slope of 2H:1V (Horizontal:Vertical) for all permanent cut and fill slopes. Based on our review of the Preliminary Road and Drainage Plan prepared by Barghausen Consulting Engineering, Inc. dated January 11, 2019, we anticipate permanent cut and fill slopes will be utilized in the southern portion of the site. Proposed cuts in the lots to allow construction of daylight basements will be 2H:1V, whi le slopes along the back of lots 25 through 41, in the pond area, will be 3H:1V. Where 2H:1V slopes are not feasible, retaining structures should be considered. Where retaining structures are greater than 4 feet in height (bottom of footing to top of structure) or have slopes above them, they should be designed by a qualified engineer. Fill placed on slopes that are steeper than 5H:1V (20 percent) should be "keyed" into the undisturbed native soils by cutting a series of horizontal benches, and should be constructed in accordance with Appendix J of the 2015 IBC. An excerpt from the 2015 IBC, Appendix J is included as Figure 6. The benches should be 1½ times the width of the equipment used for grading and be a maximum of 3 feet in height. Subsurface drainage may be required in areas where significant seepage is encountered during grading. Collected drainage should be directed to an appropriate discharge point. Surface drainage should be directed away from all slope faces. All slopes should be protected from erosion. Additionally, permanent slopes should be seeded and planted with a mulch, hardy vegetative groundcover or armored with quarry spalls as soon as feasible after grading is completed. 150 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 14 Stormwater Infiltration The soils encountered in our subsurface explorations varied slightly across the site. As stated, mottling was observed in some of our previous test pits at approximately 2½ to 6 feet below the existing ground surface, and mottling, an indicator of seasonal high perched groundwater table was observed in all our recent test pits at approximately 1 to 3 feet below the existing ground surface. Groundwater seepage was also observed in four of our previous test pits at approximately 2 to 8½ feet below the existing ground surface at the time of excavation. Some previously placed, undocumented fill was also observed below the existing ground surface in portions of the project site. We performed two small scale pilot infiltration testing PIT-1 and PIT-2 in general accordance with the 2012 Department of Ecology Stormwater Management Manual for Western Washington (SWMMWW), Volume III, Section 3.3.6. Indicators of impermeable layers underlying the infiltration pits were observed when we over-excavated the test location following completion of the infiltration testing, as required. Per the 2012 Stormwater Management Manual for Western Washington (SWMMWW), with the 2014 amendments, Volume III, Section 3.3.7, a minimum of 1 foot of separation is required between the bottom of a proposed infiltration facility and the top of an impermeable layer, such as a seasonal high groundwater table. Per the 2012 SWMMWW, Volume III, Section 3.1.1, infiltration trenches may only be located in fill material placed and compacted under the direct supervision of a geotechnical engineer or professional civil engineer with geotechnical expertise. Based on our subsurface explorations, it is our opinion that these requirements cannot be met at the site. Given the presence of mottling, groundwater seepage, undocumented fill, and over-consolidated glacial till soils observed at the site, and the variability of the onsite soils, it is our opinion that the onsite infiltration of stormwater runoff generated by the proposed development is not feasible from a geotechnical standpoint. We recommend that the stormwater runoff generated by the proposed development be managed via alternative BMPs and stormwater management methods per the 2012 SWMMWW. All minimum setback and separation requirements and design criteria per the 2012 SWMMWW should be considered prior to the selection of a stormwater management facility. If minimum and separation setback requirements cannot be met at the site, the proposed stormwater system should be connected directly to the existing municipal stormwater system. Stormwa ter Pond The recently updated plans show the stormwater detention pond on the south side of the development (Tract A) will extend about 25 to 30 feet below existing grades. As proposed, the pond will have side slopes of 3H:1V. At the time our original explorations were completed, the Tract A was going to be an open space area. We only have explorations within the detention pond footprint, which extend down about 5 to 9 feet below grade and encountered approximately 8½ feet of undocumented fill over glacially consolidated soils. In order to evaluate the subsurface conditions and provide an opinion and geotechnical recommendations for the pond construction and the resulting slope configuration, GeoResources, LLC. should be retained to explore subsurface conditions to a depth of at least 5 feet below the proposed pond bottom. A minimum of three explorations should be performed in order to satisfy the requirements of the SWMMWW and we recommend at least one of the borings locations have a groundwater monitoring well installed. 151 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 15 EARTHWORK RECOMMENDATIONS Site Preparation All structural areas on the site to be graded should be stripped of vegetation, organic surface soils, and other deleterious materials including existing residences, ancillary structures, foundations or abandoned utility lines. Organic topsoil is not suitable for use as structural fill but may be used for limited depths in non-structural areas. Stripping depths ranging from 12 to 18 inches should be expected to remove these unsuitable soils. Thicker topsoil or organic debris may be encountered in areas of heavy vegetation or depressions. In addition to the removal of the topsoil, the undocumented fill encountered across the site should be removed or mitigated. Recommendations regarding the potential reuse of the undocumented fill and native soils are discussed in the “Suitability of On-Site Materials as Fill” section. Where placement of fill material is required, the stripped/exposed subgrade areas should be compacted to a firm and unyielding surface prior to placement of any fill. Excavations for debris removal should be backfilled with structural fill compacted to the densities described in the “Structural Fill” section of this report. We recommend that a member of our staff evaluate the exposed subgrade conditions after removal of vegetation and topsoil stripping is completed and prior to placement of structural fill. The exposed subgrade soil should be proof-rolled with heavy rubber-tired equipment during dry weather or probed with a ½-inch-diameter steel rod during wet weather conditions. Soft, loose or otherwise unsuitable areas delineated during proofrolling or probing should be recompacted, if practical, or over-excavated and replaced with structural fill. The depth and extent of over-excavation should be evaluated by our field representative at the time of construction. The areas of previously placed, undocumented fill material should be evaluated during grading operations to determine if they need mitigation; recompaction or removal. Structural Fill All material placed as fill associated with mass grading, utility trench backfill, under building areas, under retaining structures, or under roadways, should be placed as structural fill. The structural fill should be placed in horizontal lifts of appropriate thickness to allow adequate and uniform compaction of each lift. Structural fill should be compacted to at least 95 percent of MDD (maximum dry density as determined in accordance with ASTM D-1557), and the moisture content should be maintained within 2 percent of the optimum moisture content for compaction. The appropriate lift thickness will depend on the structural fill characteristics and compaction equipment used. We recommend that the appropriate lift thickness be evaluated by our field representative during construction. We recommend that our representative be present during site grading activities to observe the work and perform field density tests. The suitability of material for use as structural fill will depend on the gradation and moisture content of the soil. As the amount of fines (material passing US No. 200 sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult to achieve. During wet weather, we recommend use of well-graded sand and gravel with less than 5 percent (by weight) passing the US No. 200 sieve based on that fraction passing the 3/4-inch sieve, such as Gravel Backfill for Walls (WSDOT 9-03.12(2)). If prolonged dry 152 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 16 weather prevails during the earthwork and foundation installation phase of construction, higher fines content (up to 10 to 12 percent) may be acceptable. Material placed for structural fill should be free of debris, organic matter, trash and cobbles greater than 6-inches in diameter. The fines in the structural fill should be non-plastic. The moisture content of the fill material should be adjusted as necessary for proper compaction. Suitability of On-Site Materials as Fill During dry weather construction, the non-organic on-site outwash soil may be considered for use as structural fill; provided it meets the criteria described above in the “Structural Fill” section and can be compacted as recommended. If the soil material is over-optimum in moisture content when excavated, it will be necessary to aerate or dry the soil prior to placement as structural fill. We generally did not observe the site soils to be excessively moist at the time of our site visit. The previously placed, undocumented fill encountered across the site consists of a mixture of sand, silt, and gravel with construction debris. We do not anticipate these soils will be suitable for use as structural fill in their present condition because of their fines content and the presence of debris. The deeper, native glacial till soils encountered across the site generally consist of sand and gravel with variable amounts of fines. These soils are generally comparable to “Common Borrow” (WSDOT 9-03.14(3)) material and will be suitable for use as structural fill provided the moisture content is maintained within 2 percent of the optimum moisture level. We recommend that completed graded-areas be restricted from traffic or protected prior to wet weather conditions. The graded areas may be protected by paving, placing asphalt-treated base, a layer of free-draining material such as pit run sand and gravel or clean crushed rock material containing less than 5 percent fines, or some combination of the above. Erosion Control Weathering, erosion and the resulting surficial sloughing and shallow land sliding are natural processes. As noted, no evidence of surficial raveling or sloughing was observed at the site. To manage and reduce the potential for these natural processes, temporary and permanent erosion control measures should be installed and maintained during construction or as soon as practical thereafter to limit the additional influx of water to exposed areas and protect potential receiving waters. These construction practices should mitigate the potential erosion hazard at the site. We recommend erosion protection measures be in place prior to the start of grading activities at the site. Erosion hazards can be mitigated by applying Best Management Practices (BMP’s) outlined in the 2012 Washington State Department of Ecology’s (DOE) Stormwater Management Manual for Western Washington. If the recommended erosion and sediment control BMPs are properly implemented and maintained, it is our opinion that the planned development should not increase the potential for erosion of the site. Wet Weather and Wet Condition Considerations In the Puget Sound area, wet weather generally begins about mid-October and continues through about May, although rainy periods could occur at any time of year. Therefore, it is strongly encouraged that earthwork be scheduled during the dry weather months of June through September. Most of the soils encountered across the site contain sufficient fines to produce an unstable mixture when wet. Such soil is highly susceptible to changes in water content and tends to 153 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 17 become unstable and impossible to proof-roll and compact if the moisture content exceeds the optimum. In addition, during wet weather months, the groundwater levels could increase, resulting in seepage into site excavations. Performing earthwork during dry weather would reduce these problems and costs associated with rainwater, construction traffic, and handling of wet soil. However, should wet weather/wet condition earthwork be unavoidable, the following recommendations are provided: • The ground surface in and surrounding the construction area should be sloped as much as possible to promote runoff of precipitation away from work areas and to prevent ponding of water. • Work areas or slopes should be covered with plastic. The use of sloping, ditching, sumps, dewatering, and other measures should be employed as necessary to permit proper completion of the work. • Earthwork should be accomplished in small sections to minimize exposure to wet conditions. That is, each section should be small enough so that the removal of unsuitable soils and placement and compaction of clean structural fill could be accomplished on the same day. The size of construction equipment may have to be limited to prevent soil disturbance. It may be necessary to excavate soils with a backhoe, or equivalent, and locate them so that equipment does not pass over the excavated area. Thus, subgrade disturbance caused by equipment traffic would be minimized. • Fill material should consist of clean, well-graded, sand and gravel, of which not more than 5 percent fines by dry weight passes the No. 200 mesh sieve, based on wet-sieving the fraction passing the ¾-inch mesh sieve. The gravel content should range from between 20 and 50 percent retained on a No. 4 mesh sieve. The fines should be non-plastic. • No exposed soil should be left uncompacted and exposed to moisture. A smooth-drum vibratory roller, or equivalent, should roll the surface to seal out as much water as possible. • In-place soil or fill soil that becomes wet and unstable and/or too wet to suitably compact should be removed and replaced with clean, granular soil (see gradation requirements above). • Excavation and placement of structural fill material should be observed on a full-time basis by a geotechnical engineer (or representative) experienced in wet weather/wet condition earthwork to determine that all work is being accomplished in accordance with the project specifications and our recommendations. • Grading and earthwork should not be accomplished during periods of heavy, continuous rainfall. We recommend that the above requirements for wet weather/wet condition earthwork be incorporated into the contract specifications. Construction Observation We recommend that GeoResources, LLC be retained to observe the geotechnical aspects of construction including stripping, processing of the undocumented fill, foundations, fill placement and compaction, and drainage activities. This observation would allow us to verify the subsurface conditions as they are exposed during construction and to determine that work is accomplished in 154 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 18 accordance with our recommendations. If conditions encountered during construction differ from those anticipated, we can provide recommendations for the conditions actually encountered. Additional Services As previously stated in the Stormwater Pond section, we recommend additional subsurface explorations be completed in the newly proposed pond area in order to evaluate the subsurface conditions to the full proposed pond depth. We anticipate 3 borings will be sufficient to appropriately describe the pond subsurface soils, and at least 1 of the borings should include a groundwater monitoring well, if groundwater is encountered. An addendum report will also be required to provide our recommendations and opinions based on the additional explorations. We can provide an additional scope and budget for these tasks at your request. LIMITATIONS We have prepared this revised preliminary report for use by Stowe Construction and other members of the design team, for use in the design of a portion of this project. The data used in preparing this report and this report should be provided to prospective contractors for their bidding or estimating purposes only. Our report, conclusions and interpretations are based on our subsurface explorations, data from others and limited site reconnaissance, and should not be construed as a warranty of the subsurface conditions. Variations in subsurface conditions are possible between the explorations and may also occur with time. A contingency for unanticipated conditions should be included in the budget and schedule. Sufficient monitoring, testing and consultation should be provided by our firm during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether earthwork and foundation installation activities comply with contract plans and specifications. The scope of our services does not include services related to environmental remediation and construction safety precautions. Our recommendations are not intended to direct the contractor's methods, techniques, sequences or procedures, except as specifically described in our report for consideration in design. If there are any changes in the loads, grades, locations, configurations or type of facilities to be constructed, the conclusions and recommendations presented in this report may not be fully applicable. If such changes are made, we should be given the opportunity to review our recommendations and provide written modifications or verifications, as appropriate.    155 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 19 We have appreciated the opportunity to be of service to you on this project. If you have any questions or comments, please do not hesitate to call at your earliest convenience. Respectfully submitted, GeoResources, LLC Carson Cheung, EIT Staff Engineer in Training Keith S. Schembs, LEG Dana C. Biggerstaff, PE Principal Senior Geotechnical Engineer CC:KSS:DCB/cc Doc ID: StoweConst.56thAveS.RGu.Rev01 Attachments: Figure 1: Site Vicinity Map Figure 2a: Site Vicinity Map Figure 2b: Site and Exploration Plan Figure 3: NRCS SCS Soil Map Figure 4: USGS Geologic Map Figure 5: Typical Wall Drainage and Backfill Detail Figure 6: IBC Appendix J Detail Appendix "A" – Subsurface Explorations Appendix "B" – Laboratory Results Appendix “C” – Previous Geotechnical Engineering Report 156 of 628 Approximate Site Location (map created from King County Public GIS iMap) Not to Scale Site Location Map Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure 1 157 of 628 Approximate Site Location (map created from King County Public GIS iMap) Not to Scale Site Vicinity Map Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F January 2019 Figure 2a 158 of 628 Approximate Site Location (map created from Preliminary Road and Drainage Plan prepared by Barghausen Consulting Engineering, Inc. dated January 11, 2019) Not to scale Site and Exploration Plan Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 DocID: StoweConst.56thAveS.F2b January 2019 Figure 2b Number and approximate location of test pits TP-1 TP-7 TP-3 TP-2 TP-101 (PIT-1) TP-4 TP-6 TP-106 TP-5 TP-104 TP-105 TP-102 (PIT-2) TP-103 159 of 628 Approximate Site Location Map created from Web Soil Survey (http://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx) Soil Type Soil Name Parent Material Slopes Erosion Hazard Hydrologic Soils Group Agc Alderwood gravelly sandy loam Glacial till 8 to 15 Moderate B Not to Scale NRCS Soils Map Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure 3 160 of 628 Approximate Site Location An excerpt from the Geologic Map of the Poverty Bay 7.5-minute Quadrangle, Washington by Derek B. Booth, Howard H. Waldron, and Kathy G. Troost (2003) Qvr Recessional outwash deposits Qvt Glacial till Not to Scale USGS Geologic Map Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure 4 161 of 628 Notes Typical Wall Drainage and Backfill Detail Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure 5 1. Washed pea gravel/crushed rock beneath floor slab could be hydraulically connected to perimeter/subdrain pipe. Use of 1” diameter weep holes as shown is one applicable method. Crushed gravel should consist of 3/4” minus. Washed pea gravel should consist of 3/8” to No. 8 standard sieve. 2. Wall backfill should meet WSDOT Gravel Backfill for walls Specification 9-03-12(2). 3. Drainage sand and gravel backfill within 18” of wall should be compacted with hand-operated equipment. Heavy equipment should not be used for backfill, as such equipment operated near the wall could increase lateral earth pressures and possibly damage the wall. The table below presents the drainage sand and gravel gradation. 4. All wall back fill should be placed in layers not exceeding 4” loose thickness for light equipment and 8” for heavy equipment and should be densely compacted. Beneath paved or sidewalk areas, compact to at least 95% Modified Proctor maximum density (ASTM: 01557-70 Method C). In landscaping areas, compact to 90% minimum. 5. Drainage sand and gravel may be replaced with a geocomposite core sheet drain placed against the wall and connected to the subdrain pipe. The geocomposite core sheet should have a minimum transmissivity of 3.0 gallons/minute/foot when tested under a gradient of 1.0 according to ASTM 04716. 6. The subdrain should consist of 4” diameter (minimum), slotted or perforated plastic pipe meeting the requirements of AASHTO M 304; 1/8-inch maximum slot width; 3/16- to 3/8- inch perforated pipe holes in the lower half of pipe, with lower third segment unperforated for water flow; tight joints; sloped at a minimum of 6”/100’ to drain; cleanouts to be provided at regular intervals. 7. Surround subdrain pipe with 8 inches (minimum) of washed pea gravel (2” below pipe” or 5/8” minus clean crushed gravel. Washed pea gravel to be graded from 3/8-inch to No.8 standard sieve. 8. See text for floor slab subgrade preparation. Materials Drainage Sand and Gravel ¾” Minus Crushed Gravel Sieve Size % Passing by Weight Sieve Size % Passing by Weight ¾” 100 ¾” 100 No 4 28 – 56 ½” 75 – 100 No 8 20 – 50 ¼” 0 – 25 No 50 3 – 12 No 100 0 – 2 No 100 0 – 2 (by wet sieving) (non-plastic) 162 of 628 IBC Appendix J Detail Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 DocID: StoweConst.56thAveS.F September 2018 Figure 6 163 of 628 Appendix A Subsurface Explorations 164 of 628 SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP SYMBOL GROUP NAME COARSE GRAINED SOILS More than 50% Retained on No. 200 Sieve GRAVEL More than 50% Of Coarse Fraction Retained on No. 4 Sieve CLEAN GRAVEL GW WELL-GRADED GRAVEL, FINE TO COARSE GRAVEL GP POORLY-GRADED GRAVEL GRAVEL WITH FINES GM SILTY GRAVEL GC CLAYEY GRAVEL SAND More than 50% Of Coarse Fraction Passes No. 4 Sieve CLEAN SAND SW WELL-GRADED SAND, FINE TO COARSE SAND SP POORLY-GRADED SAND SAND WITH FINES SM SILTY SAND SC CLAYEY SAND FINE GRAINED SOILS More than 50% Passes No. 200 Sieve SILT AND CLAY Liquid Limit Less than 50 INORGANIC ML SILT CL CLAY ORGANIC OL ORGANIC SILT, ORGANIC CLAY SILT AND CLAY Liquid Limit 50 or more INORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT CH CLAY OF HIGH PLASTICITY, FAT CLAY ORGANIC OH ORGANIC CLAY, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: SOIL MOISTURE MODIFIERS: 1. Field classification is based on visual examination of soil Dry- Absence of moisture, dry to the touch in general accordance with ASTM D2488-90. Moist- Damp, but no visible water 2. Soil classification using laboratory tests is based on ASTM D2487-90. Wet- Visible free water or saturated, usually soil is obtained from below water table 3. Description of soil density or consistency are based on interpretation of blow count data, visual appearance of soils, and or test data. Unified Soils Classification System Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure A-1 165 of 628 Test Pit TP-101 (PIT-1) Location: NE corner of parcel 9262800295 Approximate Elevation: 431’ Depth (ft) Soil Type Soil Description 0 - 0.5 - Brown topsoil/crushed rock (loose, moist) 0.5 - 2.0 SM Brown silty SAND with gravel and some to trace organics (medium dense, originally moist, saturated from infiltration testing) (fill) 2.0 - 3.0 - Dark brown relict topsoil with abundant organics (loose, saturated from infiltration testing) 3.0 - 4.0 SM Reddish brown with iron oxide staining/mottling silty SAND with gravel (loose to medium dense, moist) (weathered till) 4.0 - 5.0 SM Brown grey silty SAND with gravel (medium dense becomes dense, moist) (till) Terminated at 5 feet below ground surface. Iron oxide staining/mottling observed at 3 feet below existing ground surface. No groundwater seepage observed at the time of excavation. Some minor caving observed at 2.5 feet below existing ground surface (infiltration testing) Test Pit TP-102 (PIT-2) Location: NW corner of parcel 92682800313 Approximate Elevation: 420’ Depth (ft) Soil Type Soil Description 0 - 0.7 - Dark brown topsoil with roots and organics (loose, moist) 0.7 - 2.6 GP-GM Brown grey with some iron oxide staining/mottling poorly-graded GRAVEL with silt and sand (loose to medium dense, originally moist, saturated from infiltration testing) 2.6 - 5.0 GM Grey silty GRAVEL with sand (dense, saturated likely from infiltration testing, become moist at about 3.5 feet below existing ground surface) (gravely till?) Terminated at 5 feet below ground surface. Some iron oxide staining/mottling observed at 1.2 feet below existing ground surface. No groundwater seepage observed at the time of excavation. No caving observed at the time of excavation. Logged by: CC Excavated on: September 25, 2018 Test Pit Logs Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure A-2 166 of 628 Test Pit TP-103 Location: South central portion of parcel 9262800313 Approximate Elevation: 419’ Depth (ft) Soil Type Soil Description 0 - 1.0 - Dark brown topsoil with roots and organics (loose, dry to moist) 1.0 - 3.0 SM Brown grey with iron oxide staining/mottling silty SAND with gravel (loose to medium dense, dry to moist) (weathered till) 3.0 - 4.5 SM Grey silty SAND with gravel (dense, dry to moist) (till) Terminated at 4.5 feet below ground surface. Iron oxide staining/mottling observed at 1 foot below existing ground surface. No groundwater seepage observed at the time of excavation. No caving observed at the time of excavation. Test Pit TP-104 Location: North central portion of parcel 9262800313 Approximate Elevation: 424’ Depth (ft) Soil Type Soil Description 0 - 1.0 - Dark brown topsoil with roots and organics (loose, dry to moist) 1.0 - 2.0 SM Brown grey with iron oxide staining/mottling silty SAND with gravel (loose to medium dense, dry to moist) (weathered till) 2.0 - 5.5 SM Grey silty SAND with gravel and cobbles (dense, dry to moist) (till) Terminated at 5.5 feet below ground surface. Iron oxide staining/mottling observed at 1 foot below existing ground surface. No groundwater seepage observed at the time of excavation. No caving observed at the time of excavation. Logged by: CC Excavated on: September 25, 2018 Test Pit Logs Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure A-3 167 of 628 Test Pit TP-105 Location: NE corner of parcel 9262800313 Approximate Elevation: 414’ Depth (ft) Soil Type Soil Description 0 - 1.0 - Dark brown topsoil with roots and organics (loose, moist) 1.0 - 2.5 SM Brown with iron oxide staining/mottling silty SAND with gravel and occasional boulder (medium dense, moist) (weathered till) 2.5 - 5.5 SM Grey silty SAND with gravel (dense, moist) (till) Terminated at 5.5 feet below ground surface. Iron oxide staining/mottling observed at 1 foot below existing ground surface. No groundwater seepage observed at the time of excavation. No caving observed at the time of excavation. Test Pit TP-106 Location: SE corner of parcel 9262800313 Approximate Elevation: 414’ Depth (ft) Soil Type Soil Description 0 - 1.0 - Dark brown topsoil with roots and organics (loose, moist) 1.0 - 2.0 GM Brown with iron oxide staining/mottling silty GRAVEL with sand and occasional boulder (medium dense, moist) (weathered gravely till?) 2.0 - 5.5 SM Brown grey silty SAND with gravel (dense, moist) (till) Terminated at 5.5 feet below ground surface. Iron oxide staining/mottling observed at 1 foot below existing ground surface. No groundwater seepage observed at the time of excavation. No caving observed at the time of excavation. Logged by: CC Excavated on: September 25, 2018 Test Pit Logs Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure A-4 168 of 628 Appendix B Laboratory Analyses 169 of 628 These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By: Particle Size Distribution Report PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 13.1 49.9 9.1 7.1 13.7 7.16 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM D 422 & ASTM C 117) Opening Percent Spec. *Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: TP-102, S-1 Sample Number: 095623 Depth: 2' Client: Project: Project No:Figure Brown poorly-graded GRAVEL with silt and sand 1 .75 .5 .3125 #4 #10 #20 #40 #60 #100 #200 100.0 86.9 68.7 57.0 37.0 27.9 22.4 20.8 12.5 9.4 7.1 NP NV NP GP-GM A-1-a 20.3975 18.2684 8.9716 6.6366 2.4341 0.2932 0.1662 53.98 3.97 10/2/2018 CC/NF KSS PM 9/25/2018 Mr. Byran Stowe StoweConst.56thAveS StoweConst.56thAveS PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) GeoResources, LLC Fife, WA 170 of 628 These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By: Particle Size Distribution Report PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 20.9 35.0 9.0 10.8 11.9 12.46 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM D 422 & ASTM C 117) Opening Percent Spec. *Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: TP-106, S-1 Sample Number: 095633 Depth: 1-3' Client: Project: Project No:Figure Brown silty GRAVEL with sand 1.25 1 .75 .5 .3125 #4 #10 #20 #40 #60 #100 #200 100.0 88.8 79.1 65.6 59.8 44.1 35.1 29.5 24.3 19.5 16.1 12.4 NP NV NP GM A-1-a 26.0204 22.6961 8.0962 5.7661 0.9212 0.1225 10/2/2018 CC/NF KSS PM 9/25/2018 Mr. Byran Stowe StoweConst.56thAveS StoweConst.56thAveS PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) GeoResources, LLC Fife, WA 171 of 628 These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By: Particle Size Distribution Report PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 7.9 31.1 11.8 16.4 18.6 14.26 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM D 422 & ASTM C 117) Opening Percent Spec. *Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: TP-106, S-2 Sample Number: 095634 Depth: 3-5.5' Client: Project: Project No:Figure Grey silty SAND with gravel 1 .75 .5 .3125 #4 #10 #20 #40 #60 #100 #200 100.0 92.1 83.4 75.7 61.0 49.2 40.7 32.8 24.9 19.1 14.2 NP NV NP SM A-1-b 17.2541 13.6730 4.4078 2.1209 0.3527 0.0845 10/2/2018 CC/NF KSS PM 9/25/2018 Mr. Byran Stowe StoweConst.56thAveS StoweConst.56thAveS PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) GeoResources, LLC Fife, WA 172 of 628 PRELIMINARY STORMWATER SITE PLAN Carbon Trails SEP19-0003 PLT19-0002 FAC#19-XXXX 32727 56th Avenue South Auburn, WA 98001 Applicant/Owner: Stowe Investments LLC PO Box 1054 Sumner, WA 98390-0200 Bryan Stowe 253-606-8741 stowerock@aol.com Engineer: Barghausen Consulting Engineers, Inc. 18215 72nd Avenue South Kent, WA 98032 425-251-6222 Jason G. Hubbell, P.E. jhubbell@barghausen.com Karen E Harris, P.E. kharris@barghausen.com Revised April 30, 2021 Revised July 27, 2020 January 18, 2019 Our Job No. 18355 4/30/2021 173 of 628 18355.008.doc TABLE OF CONTENTS 1.0 PROJECT OVERVIEW ..................................................................................................................... 1 2.0 EXISTING CONDITIONS SUMMARY .............................................................................................. 4 3.0 OFF-SITE DRAINAGE ANALYSIS ................................................................................................... 7 4.0 PERMANENT STORMWATER CONTROL PLAN ......................................................................... 10 4.1 THRESHOLD DISCHARGE AREAS AND APPLICABLE REQUIREMENTS FOR TREATMENT, FLOW CONTROL AND WETLANDS PROTECTION ......................... 10 4.2 PRE-DEVELOPED SITE HYDROLOGY ............................................................................. 10 4.3 DEVELOPED SITE HYDROLOGY ...................................................................................... 11 4.3.1 Project Summary .................................................................................................. 11 4.3.2 On-Site Stormwater Management System – Minimum Requirement #5 ............. 12 4.3.3 Water Quality System – Minimum Requirement #6 .............................................. 13 4.3.4 Flow Control System – Minimum Requirement #7 ............................................... 14 4.3.5 Conveyance System Analysis and Design ........................................................... 14 5.0 DISCUSSION OF MINIMUM REQUIREMENTS ............................................................................ 16 174 of 628 18355.008.doc LIST OF EXHIBITS Exhibit A - Vicinity Map ......................................................................................................... 19 Exhibit B – Existing Conditions Summary Site Map ............................................................. 21 Exhibit C – Downstream Drainage Maps .............................................................................. 23 Exhibit D - Basin Map ............................................................................................................ 27 Exhibit E – Site Map and Grading Plans ............................................................................... 29 175 of 628 18355.008.doc ATTACHMENTS ATTACHMENT A OPERATION AND MAINTENANCE MANUAL .......................................................... 57 ATTACHMENT B STORMWATER POLLUTION PREVENTION PLAN ................................................ 76 ATTACHMENT C HYDRAULIC/HYDROLOGIC ANALYSIS AND MODELING RESULTS ................... 78 ATTACHMENT D OTHER SPECIAL REPORTS.................................................................................. 145 D1 - GEOTECHNICAL REPORT ............................................................................. 146 D2 - CRITICAL AREAS REPORT ........................................................................... 182 ATTACHMENT E DECLARATION OF COVENANT FOR PRIVATELY MAINTAINED FACILITIES ... 207 ATTACHMENT F DOWNSTREAM QUANTITATIVE ANALYSIS ......................................................... 209 176 of 628 Tab 1.0 177 of 628 18355.008.doc 1.0 PROJECT OVERVIEW The proposal for this project is to obtain permits associated with final development of the site. Specifically, this report is to begin design review and approval of storm improvements associated with a Preliminary Plat and SEPA review. SEP19-0003 PLT19-0002 FAC19-XXXX Other permits required for this project include: · NPDES Construction Storm Water Discharge Permit · Demolition Permit · Lakehaven Sewer Extension and Side Sewer Permits · Water Permit · Building Permit for Retaining Walls · City of Auburn Building, Plumbing, Demolition and Mechanical Permits · City of Auburn Building, FAC and Grading Permit and Level 3 Storm Permit The proposed project is to develop three parcels in Auburn for a single family residential plat. The three parcels are approximately 11.4 acres combined. The project is located within Section 14, Township 21 North, Range 4 East, Willamette Meridian, City of Auburn, King County, Washington. More particularly, the site is located between 51st and 56th Avenue South at S 328th Street. Please refer to Exhibit A - Vicinity Map. The site lies within a single family zoned area. A lot of the area is still rural type homes with large lots but there is a parcel to the south and east that have been developed into small subdivisions. One of the parcels being developed is 32727 56th Avenue South, Auburn, WA 98001. Assessor parcel numbers are 926280 -0320, -0295 and - 0313. The current zoning is R-5 residential. Please see Section 2.0 for a detailed description of the existing site. Two of the three existing parcels are vacant and are mainly covered in trees. One parcel includes a single family home and detached garage. The existing home will be demolished with this proposed development. There is an existing wetland along the north property line that will remain in the developed conditions. The proposal is to create approximately 44 single family lots for development. The project would include platting, road improvements, utility extensions, storm drainage conveyance, water quality and detention to meet the City of Auburn requirements. The residential plat would meet the current R-5 zoning, including minimum lot sizes, setbacks and impervious surface coverage. The proposed single family homes would likely be in the 2500-3500 square foot range with fenced yards and appropriate landscaping and street trees. Please see Exhibit D for the developed conditions. 1 178 of 628 18355.008.doc The storm detention system is sized according to the 2014 Department of Ecology Manual. The system is designed with 4 feet of live storage in a water quality and detention pond along the south edge of the site. The pond is being designed to meet City of Auburn construction requirements. City standards require that matching developed discharge durations to predeveloped durations for the range of predeveloped discharge rates from 50% of the 2-year peak flow up to the full 50-year peak flow. See section 4.0 for the calculations to size the storm detention system. A continuous simulation model program, WWHM2012 has been used to determine the required size of the pond and wet pond for water quality treatment. Pipes conveying runoff to the ponds will be sized using SBUH methodology. A portion of the site runoff will be directed to the existing wetland to match existing conditions. A catch basin (CB #12) is proposed at the north end of access Tract D to provide a wetland overflow route to the pond. Detained runoff from the detention pond will discharge west to 51st Avenue South and then south within the right-of-way. Runoff discharges about ¼ mile from the site where runoff flows into the ravine just north of SR-18. The flow crosses SR-18 and enters Mill Creek. Mill Creek flows east along Peasley Canyon then north along SR-167. Mill Creek continues north eventually reaching the Green River. The site is proposing to detain storm runoff and release at or below existing rates. A storm conveyance extension is also proposed to route runoff downstream. This will ensure that this development does not alter how the existing downstream system functions or cause a drainage issue on a neighboring property. 2 179 of 628 3 Tab 2.0 180 of 628 18355.008.doc 2.0 EXISTING CONDITIONS SUMMARY There is currently a single family residence and detached garage on the northeastern parcel that will be removed with this development. The southern parcels are vacant. Besides the two buildings, the remainder of the site is covered in trees and brush. Most of the site slopes toward the center of the site and then to the south. A small part of the western side of the site slopes toward the west. There is an existing wetland along the northern property line of this site. The wetland is approximately one acre in size and extends to the north. Based on the King County iMap, it appears the wetland is located on a relatively level, ridge line area north of the site. To the north of the wetland area, the ground slopes north and slopes south on the project site. It is assumed the wetland overflows both north and south. An existing overflow culvert on the south side of the wetland was found by the wetland consult but a discharge location could not be found. See Exhibit B for the existing conditions map. Some areas to the north and west flow onto this site creating an upstream basin. Most of the site flows south in a gentle swale. The western portion of the site drains west to 51st Avenue South and then south within the right-of-way. There are some historical drainage problems along the downstream drainage path. See Exhibit C for a general downstream drainage map which shows some drainage complaints that are shown on the King County iMap. Existing utilities available on or adjacent to the site are, electricity, water, gas, phone, and refuse service. The site is within the Lakehaven Water and Sewer District. Sanitary sewer will have to be extended to the project site from northwest of the site. There are no known areas with a high potential for erosion or sedimentation deposition. There are no known fuel tanks on site. There are two groundwater wells located northeast of the site, approximately 170 feet and 370 feet from the property line. The site is located in the 10-year wellhead protection area for a City of Auburn well to the northeast (West Hill Spring). A septic system for the existing home is on site and will be removed once the project is developed. There are a few Department of Ecology toxic cleanup sites downstream from the site along Mill Creek. One is currently being cleanup and a couple at the intersection of SR-167 and Peasley Canyon are awaiting cleanup. This site is designated as drainage for a landslide hazard area. The steep slopes adjacent to SR- 18 are shown on King County iMap as a landslide hazard and erosion hazard area. A map of the landslide hazard area has been added to Exhibit C. There is no FEMA mapped floodplain on this site. Under the pre-developed conditions, this site was assumed to be undisturbed forested condition for hydrologic group "C" or till type soils. Per the soils map, the onsite soils are Alderwood Gravelly Sandy Loam. The geotechnical report (Attachment D) encountered approximately 1-8.5 feet of fill soils during testing. Below the topsoil and fill materials, weathered and glacial till was encountered. Groundwater seepage was encountered in the test pits in 2017 but not during the more recent testing. The groundwater elevation is assumed to be 5-10 feet below the existing 4 181 of 628 18355.008.doc ground as is typical in other areas of Auburn. Infiltration testing was performed but it was determined the infiltration was not down into subsurface soils but along shallow layers of sand and gravel. Infiltration of stormwater onsite is not recommended by the geotechnical engineer. The site does not meet the requirements of a geologic hazard area. 5 182 of 628 6 Tab 3.0 183 of 628 18355.008.doc 3.0 OFF-SITE DRAINAGE ANALYSIS Refer to Attachment F for maps, drainage system table, modeling results, etc for the downstream analysis. Site Investigation The field work for this off-site analysis was performed on December 6, 2019. It was sunny but cold during the site visit with a high of 46 degrees. Most of the project site drains to the center of the site and then south in a shallow swale. A portion drains west to 51st Avenue South and then south. Both downstream drainage courses combine approximately 850 feet south of the site where the drainage course crosses South 331st Street and enters the ravine down to SR-18 and Mill Creek. Therefore this entire site is considered one threshold discharge area. The swale south is on private property and mostly forested. There is an existing home south of the property that is near the swale. GIS record information was obtained from the City of Auburn showing the existing storm system in 51st Avenue South, 46th Place South and South 331st Street. The City information was used to verify the storm routing. There is an existing catch basin at the 51st Avenue South and S 329th Street. Runoff is conveyed south in pipes to S 331st Street where runoff is discharged to an existing ditch on the north side of the road. Runoff continues east in ditches and driveway culverts until east of 52nd Avenue South where a pipe flows south and discharges into the ravine north of SR-18. This is approximately where the swale from the north connects to the downstream path. The road is approximately 5’ higher than the pipe flowing south. GIS records indicate the pipe is a 12” concrete pipe. The pipe was not visible due to the ditch being heavily vegetated. The ditch along S 331st Street is shallow in some areas and with very steep side slopes. Some bare soils along the ditch banks were visible but most of the ditches were vegetated with grass and ivy. Reviewing the GIS data provided, the downstream pipes are all 12” pipes. Along 51st Avenue South the pipes are pretty steep but some of the culverts and ditches have a reverse slope along South 331st Street which may cause some temporary ponding. No standing water was observed during the site visit. There was no evidence of flooding or other issues during the site visit. Most of the downstream area is developed with rural type single family homes. Capacity Analysis Because a portion of this site drains over private property with an unknown drainage path and close to an existing home, the City of Auburn has required a quantitative analysis be performed on the downstream conveyance system from this project site, down the drainage route that lies within the right-of-way to verify the existing conditions and existing performance of the system. The existing upstream and downstream basins were mapped using field survey and LIDAR topography data. Existing land cover was estimated using aerial photographs. Soil type was assumed from USDA soil survey information. Survey was performed on the existing ditches and culverts along 51st Avenue South and South 331st Street. 7 184 of 628 18355.008.doc Per Appendix III-D of the City of Auburn Supplemental Manual, the conveyance system is modeled for the 25-year, 24 hour peak flow rate without surcharging and the water depth in the pipe must not exceed 90% capacity. The 100-year storm event was also modeled to show any areas flooding. Besides the project area, the conveyance system basin is developed with rural type single family homes. Existing conditions were modeled based on LIDAR survey and aerial photographs. Since the discharge point was to a steep ravine, normal tailwater conditions (free flowing pipe) were assumed. The existing downstream system was modeled, including the detained flows from the project site. There are several areas of flooding during the 25-year, 24 hour storm event. The 100-year flows were also modelled. If the project runoff is routed through the existing system there is localized flooding during the 25-year and 100-year events, likely due to the reverse slopes, lack of ditch depth and small culverts in the system. Some potential fixes to the downstream system were explored to make the conveyance work. The existing pipes and ditches were modeled with positive slopes, larger widths or larger pipes. After obtaining the field survey of the downstream system, it was discovered that some of the existing culverts and ditches were not located within the mapped right-of-way. In order to fix capacity issues, drainage and construction easements would be required to be obtained for multiple property owners. Another option to alleviate the downstream capacity issues was the installation of a new storm conveyance system to route site drainage from this site, south in 51st Avenue South and then east in South 331st Street to the discharge point at the existing ravine. By routing the site drainage in a new conveyance system, flows in the existing culverts and ditches will be reduced. The map included in Attachment F highlights the properties that would continue to discharge to the roadside ditches and culverts. Without the upstream flows contributing to the roadside ditches and culverts, the flooding is eliminated. The 100-year event was modeled and no flooding occurs in the proposed condition. Since runoff from the project site is being detained to existing conditions there is no increase in flows at the discharge point to the ravine. 8 185 of 628 9 Tab 4.0 186 of 628 18355.008.doc 4.0 PERMANENT STORMWATER CONTROL PLAN 4.1 THRESHOLD DISCHARGE AREAS AND APPLICABLE REQUIREMENTS FOR TREATMENT, FLOW CONTROL AND WETLAND PROTECTION This site discharges runoff to an existing swale to the south at the center of the site and to an existing ditch at the southwest corner of the site. Both downstream drainage courses combine approximately 850 feet south of the site where the drainage course crosses South 331st Street and enters the ravine down to SR-18 and Mill Creek. Therefore this entire site is considered one threshold discharge area. The site proposes impervious surfaces and clearing activities which trigger all the minimum requirements. Standard flow control is being proposed for the basin, this will ensure that development does not aggravate any downstream conveyance issues. This site is shown not within the floodplain on the applicable FIRM maps. There is an existing wetland at the north property line that will remain with the development and flows will be routed to maintain the wetland hydrology. 4.2 PRE-DEVELOPED SITE HYDROLOGY The existing site has one residential home with a detached garage. Most of the rest of the site is covered with large trees. The existing site is modeled as till soil, moderate slope forested conditions. There are several offsite basins being included in the design and they are modeled as forest with some impervious to match the actual existing conditions. Sub-Basin ID Existing Land Use and Cover Condition Acreage Soil Group Modeled As Comments Basin 1 (Onsite Property) Residential home, grass, shrubs and trees 13.76 ac C Forest Moderate Slope Offsite 1 Two existing homes northwest of site 1.81 ac C 1.56 ac forest 0.25 ac impervious Moderate Flat Offsite 2 West of wetland 0.08 ac C Forest Moderate Offsite 3 Basin to wetland 2.17 ac C Forest Moderate Offsite 4 Existing home on east side of site 1.15 ac C 0.58 ac Forest 0.57 ac impervious Moderate Flat 10 187 of 628 18355.008.doc Pre-Developed Condition Event Output: WWHM Peak Flow (cfs) Area (ac) 2-yr Existing 0.7684 18.97 10-yr Existing 1.4883 18.97 25-yr Existing 1.9224 18.97 100-yr Existing 2.6591 18.97 4.3 DEVELOPED SITE HYDROLOGY 4.3.1 Project Summary The developed site and the offsite basins are designed to be routed to the pond. As design progresses, a portion of the northeast corner (backyard drainage from Lots 1-6 and Lot 17) will be routed to the wetland for maintain wetland hydrology. The wetland will function as is does currently, ponding water until it overflows to the south. This operation will be maintained in the developed condition by installing an overflow catch basin that will act as the outlet for the wetland and route runoff to the pond and then to the south. This matches the current drainage pattern. There is some area at the western edge of the site that drains to 51st Avenue South. That area will be routed to the detention pond for detention and water quality. A flow splitter will be used on the pond outlet to route some of the drainage to 51st Avenue South to match existing conditions. The water quality and detention pond have been designed to treat and detain runoff form S 328th Street as well as the proposed home site. It was assumed the onsite basin would be approximately 65% impervious in the developed condition. The offsite basins were modeled the same as in the existing condition. Sub-Basin ID Developed Land Use and Cover Condition Acreage Soil Group Modeled As Comments SITE R-5 Residential, 65% Impervious 13.76 ac C 0.37 ac forest (wetland and buffer) 2.77 ac lawn flat 1.88 ac lawn steep 8.74 ac impervious Offsite 1 Two existing homes northwest of site 1.81 ac C 1.56 ac forest 0.25 ac impervious Moderate Flat 11 188 of 628 18355.008.doc Offsite 2 West of wetland 0.08 ac C Forest Moderate Offsite 3 Basin to wetland 2.17 ac C Forest Moderate Offsite 4 Existing home on east side of site 1.15 ac C 0.58 ac Forest 0.57 ac impervious Moderate Flat Developed Condition Event Output: WWHM Undetained Peak Flow (cfs) Area (ac) 2-yr Developed 4.1184 18.97 10-yr Developed 6.2548 18.97 25-yr Developed 7.4160 18.97 100-yr Developed 9.2599 18.97 Developed Condition Event Output: WWHM After Detention POC 1 (Pond) Peak Flow (cfs) Area (ac) 2-yr Developed 0.3973 18.97 10-yr Developed 0.7658 18.97 25-yr Developed 1.0271 18.97 100-yr Developed 1.5342 18.97 4.3.2 On-Site Stormwater Management System – Minimum Requirement #5 This development triggers all of the minimum requirements, including Minimum Requirement #5 – Stormwater Management. In order to meet this requirement, List #2 was evaluated for each surface to determine which LID BMPs could be used on this site. See below for feasibility analysis: · Lawn and Landscape Areas: o Post-Construction Soil Quality and Depth (BMP T5.13)  This will be noted on the FAC plans to be implemented 12 189 of 628 18355.008.doc · Roof Areas: o Full Dispersion (BMP T5.30)  The site is not protecting at least 65% of the site as existing or forested condition; therefore this BMP is infeasible. o Bioretention  Infiltration is not recommended on this site so this BMP is deemed infeasible. o Downspout Dispersion (BMP T5.10B)  The dispersion path of 25 feet to the property line cannot be met on the proposed residential lots; therefore this BMP is infeasible. o Perforated Stub-Out Connections (BMP T5.10C)  The FAC plans will specify the roof drain connections to the street will be perforated. · Other Hard Surfaces: o Full Dispersion (BMP T5.30)  The site is not protecting at least 65% of the site as existing or forested condition; therefore this BMP is infeasible. o Permeable Pavement (BMP T5.15)  Infiltration is not recommended on this site so this BMP is deemed infeasible. o Bioretention  Infiltration is not recommended on this site so this BMP is deemed infeasible. o Sheetflow Dispersion (BMP T5.12)  There is not suffiecient space at a moderate slope to accommodate sheetflow dispersion for the proposed roads or driveways. At the northeast corner of the site, backyard drainage will be routed to the existing wetland in a shallow swale to match pre-developed hydrology. This swale will act as a dispersion BMP for that area. 4.3.3 Water Quality System – Minimum Requirement #6 The proposed water quality system is a wetpool in the pond to provide basic water quality for the residential development as required. The wetpool volume matches the 24-hour water quality volume as calculated using the WWHM2012 program. 13 190 of 628 18355.008.doc The WWHM output is included in Attachment C. 4.3.4 FLOW CONTROL SYSTEM – Minimum Requirement #7 Flow control is being proposed for this basin of the proposed project using forested as the existing condition and the final developed site as the developed condition. The detention pond was sized using WWHM2012. The pond has 4 feet of live storage depth and requires 3.95 ac-ft of detention storage. A control structure is located on the south side of the site that will discharge detained runoff to a flow dispersion trench that will discharge south and some runoff will be routed west to 51st Avenue South. Please also see the pond basin calculations for sizing and control structure design included in Attachment C. 4.3.5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN The conveyance system sizing for the development will utilize the Santa Barbara Urban Hydrograph (SBUH) method. The conveyance system calculations will be included within this section with the civil permit submittal. The conveyance calculations will be included within Attachment C when complete. 14 191 of 628 15 Tab 5.0 192 of 628 18355.008.doc 5.0 DISCUSSION OF MINIMUM REQUIREMENTS Minimum Requirement #1: Preparation of a Stormwater Site Plan This Stormwater Site Plan has been prepared in accordance with the 2014 Department of Ecology Stormwater Management Manual. Minimum Requirement #2: Construction Stormwater Pollution Prevention (SWPP) A SWPPP will be prepared for this project in accordance with the 2014 Department of Ecology Stormwater Management Manual during the civil permit application. The SWPPP will be located within Appendix B of this report. Minimum Requirement #3: Source Control of Pollution Source Control of Pollution during the clearing and grading portion of this project have been designed in accordance with City of Auburn standards and will be described in further detail within the SWPPP. Permanent Source Control for this residential development will include an Operations and Maintenance Manual for the storm system and labels on the catch basins to dump no wastes into the storm system. Minimum Requirement #4: Preservation of Natural Drainage Systems Stormwater will be discharged from the proposed project site near the existing natural locations after being detained in an open detention pond. The pond will discharge to the 51st Avenue South right of way and will continue south and then east along South 321st to the discharge point south of the site. The pond has been designed in accordance with the 2014 Department of Ecology Stormwater Management Manual. Minimum Requirement #5: On-Site Stormwater Management This development triggers all of the minimum requirements, including Minimum Requirement #5 – Stormwater Management. In order to meet this requirement, List #2 was evaluated for each surface to determine which LID BMPs could be used on this site. See Section 4.3.2 for additional narrative. Minimum Requirement #6: Runoff Treatment As a residential development, only basis water quality treatment is required. Basic treatment will be provided by an open wetpool in the detention pond. Minimum Requirement #7: Flow Control Flow control is triggered for this development. Flow control will meet the Department of Ecology and City of Auburn requirements. An open detention pond along the south side of the site is proposed for flow control. See Section 4.3.4 for additional narrative. Minimum Requirement #8: Wetland Protection There is an existing wetland on the north property line. The development is being developed to route some site runoff to the wetland (backyard drainage from Lots 1-6 and Lot 17) to maintain existing wetland hydrology. The wetland will continue to pond and 16 193 of 628 18355.008.doc overflow to the south through the site. A 50’ buffer is proposed around the wetland and is not proposed to be disturbed. Minimum Requirement #9: Operation and Maintenance An operations and maintenance manual is included as Attachment A. Minimum Requirement #10: Off-Site Analysis and Mitigation An off-site drainage analysis is included in section 3.0 of this report. 17 194 of 628 18 Exhibits 195 of 628 19 Exhibit A Vicinity Map 196 of 628 20 197 of 628 21 Exhibit B Existing Conditions Summary Site Map 198 of 628 22WETLAND AWETLANDOVERFLOWELEVATIONAPPROX. 412EXISTING DITCHBASIN LINE(Typ.)Onsite BasinProperty Area13.76 acOffsite 32.17 acOffsite 11.81 acOffsite 20.08 acOffsite 41.15 acdischarge locationDischarge location199 of 628 23 Exhibit C Downstream Drainage Maps 200 of 628 24 Ponding complaint due to neighbor regrading ravine to SR-18. Landslide hazard area catch basin with pipes flowing south, storm conveyance extends to ravine location basin/ridge line Downstream Drainage Map 201 of 628 25 202 of 628 King King County iMap Date: 7/23/2020 Notes: The information included on this map has been compiled by King County staff from a variety of sources and is subject to changewithout notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness,or rights to the use of such information. This document is not intended for use as a survey product. King County shall not be liablefor any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profitsresulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map isprohibited except by written permission of King County.± 26 SITE LANDSLIDE HAZARD AREA 203 of 628 27 Exhibit D Basin Map 204 of 628 28Backyard drainage towetlandWETLAND AWETLANDOVERFLOWELEVATIONAPPROX. 412Detentionand WaterQuality PondControl Structure andFlow SplitterFlow Dispersal TrenchFlow to 51st Ave S205 of 628 29 Exhibit E Site Map and Grading Plans 206 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallR                                       30207 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR31208 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR32209 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallR33210 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR34211 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR35212 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR36213 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR37214 of 628 CARBON TRAILS38215 of 628 CARBON TRAILS39216 of 628 CARBON TRAILS40217 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR41218 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR42219 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallRCAUTION:43220 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR44221 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallRSCALE: 1"=40'45222 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallRSCALE: 1"=40'46223 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallRSOD LAWN IN ALL LANDSCAPE STRIPS,TYPICAL. LAWN HATCH NOT SHOWN.LANDSCAPE CONTRACTOR TOCALCULATE QUANTITIESREFER TO CITY OF AUBURN STREET TREEPLANTING/STAKING STANDARD DETAILTRAFFIC-14. GATOR BAGS OR APPROVED EQUALARE REQUIRED FOR ALL STREET TREES.MAINTENANCE SHALL INCLUDE THE BAGSDURING SUMMER MONTHS 2X PER WEEK.HYDROSEED SLOPES WITHIN STORM POND.SEE SEED LIST THIS SETSTREET TREES OMITTEDDUE TO SLOPESSTREET TREE OMITTEDDUE TO CONFLICTWITH HYDRANTSTREET TREE OMITTEDDUE TO CONFLICTWITH LUMIERE POLEALL STREET TREESOMITTED WITHIN SIGHTDISTANCE TRIANGLE, TYP.ALL STREET TREESOMITTED WITHIN SIGHTDISTANCE TRIANGLE, TYP.47224 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallRHYDROSEED SLOPES WITHIN STORM POND.SEE SEED LIST THIS SETSTREET TREE OMITTED DUETO CONFLICT WITH HYDRANTAND LUMIERE POLEALL STREET TREESOMITTED WITHIN SIGHTDISTANCE TRIANGLE, TYP.ALL STREET TREESOMITTED WITHIN SIGHTDISTANCE TRIANGLE, TYP.48225 of 628 SCALE: 1"=200'N4/07/20214/07/202149226 of 628 SCALE: 1"=50'N4/07/202150227 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR51228 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR52229 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR53230 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR54231 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR55232 of 628 56 Attachments 233 of 628 57 Attachment A Operations and Maintenance Manual 234 of 628 OPERATIONS AND MAINTENANCE MANUAL FOR THE STORM DRAINAGE FACILITIES Carbon Trails South 328th Street, between 51st Ave S and 56th Ave S Auburn, WA 98001 Prepared for: Stowe Investments LLC PO Box 1054 Sumner, WA 98390-0200 Bryan Stowe 253-606-8741 stowerock@aol.com January 18, 2019 Our Job No. 18355 58 235 of 628 18355.009.doc 1.0 SITE ADDRESS Carbon Trails is located at S 328th Street between 51st Avenue South and 56th Avenue South in Auburn Washington. 2.0 INTRODUCTION The site has a drainage system that needs periodic maintenance in order to function properly. This report describes the storm drainage system and delineates operation and maintenance responsibilities and requirements for the site. The design of the drainage facilities discussed in this manual can be found in the Carbon Trails project construction drawings and stormwater site plan on file with the City of Auburn. The site is approximately 13.6 acres in size. The purpose of this manual is to address maintenance of stormwater facilities installed with the construction of the Carbon Trails project. These facilities are intended to detain and treat the developed site and the runoff from S 328th Street. Runoff on the project site is sent to the storm water detention pond via catch basins and underground pipes. There is also a permanent wetpool in the pond area to treat pollutants from the site. 3.0 PLAN GOAL The specific purpose of the storm water facilities is to minimize pollution that is typically associated with modern development. Stormwater runoff contains pollutants harmful to humans and aquatic life. The majority of pollution is generated by motor vehicles and lawn / landscape maintenance. The pond detains stormwater runoff to limit the discharge rate downstream. Discharge rates must be controlled to prevent flooding and erosion of downstream parcels and water bodies. The wetpool performs water quality improvement by providing sediment removal. 4.0 MAINTENANCE AND OPERATIONAL RESPONSIBILITIES The homeowner’s association will have the following Operations and Maintenance responsibilities, which include: I. Inspection and maintenance of all on-site drainage facility components (catch basins, fencing, storm manholes, pipes, pond) at least twice annually: A. Remove accumulated sediment and debris from all pipes, structures, and pond (any debris and/or sediment collected shall be disposed of in accordance with applicable State and Federal requirements). B. Inspect and repair any damage, including; cracks, unsealed joints and pipes that deviate from their design shape C. Maintain access points including manhole hole lids, grates and ladders D. Debris and leaves shall be removed from catch basin grates E. Control structures shall be kept in good repair and ensure that the outlet orifice is unobstructed F. General site surroundings: 59 236 of 628 18355.009.doc 1) Maintaining good housekeeping practices on the site will reduce the amount of trash, debris, and sediment that reaches the storm system. 2) The homeowner’s association, neighbors and anyone doing landscaping on the property must be careful to avoid introducing landscape fertilizer to receiving waters or groundwater. 5.0 REPORTING The above maintenance activities will be documented each year and kept in a log book. Maintenance logs shall be made available to the City of Auburn upon request. This manual and the logs should be kept on-site, preferably in an office belonging to the person tasked with ensuring the system is function as intended. 6.0 RESPONSIBLE PARTY/ORGANIZATION Carbon Trails Homeowner’s Association Contact Info TBD 60 237 of 628 61 Site Map 238 of 628 62239 of 628 63240 of 628 64 Blank Maintenance Log Form 241 of 628 18355.009.doc INSPECTION/MAINTENANCE CHECKLIST The items in this checklist will be inspected at least twice per year and maintenance performed as necessary. Refer to the Maintenance Standards included in this manual for a detailed list of inspection tasks and descriptions of when maintenance is required to be performed. STRUCTURE/ FACILITY DATE OF INSPECTION MAINTENANCE Maintenance Standard(s) RESULTS/ MAINTENANCE DATE COMMENTS Pond Control Structure and outlet Sediment/Debris Cracks/Joints Grates/Damage Inspection Results Maintenance Done Pond Sediment/Debris Weeds/Insects Pollutants/Erosion Fencing/Liner Inspection Results Maintenance Done Catch Basins Sediment/Debris Cracks/Joints Grates Inspection Results Maintenance Done Conveyance Pipes Sediment/Debris Shape/Damage Inspection Results Maintenance Done General Site Landscaping Trash Fertilizer Use Inspection Results Maintenance Done 65 242 of 628 18355.009.doc I hereby certify that the above noted inspections and maintenance was performed in accordance with the approved Operations and Maintenance Manual for the Carbon Trails project, Auburn, Washington. Signature Date Title 66 243 of 628 67 Maintenance Standards 244 of 628 S U R F A C E W A T E R M A N A G E M E N T M A N U A L N O V E M B E R 2 0 0 9 Maintenance Standards for Volume I Drainage Facilities Appendix D 55 Appendix D Maintenance Standards for Drainage Facilities The facility-specific maintenance standards contained in this section are intended to be conditions for determining if maintenance actions are required as identified through inspection. They are not intended to be measures of the facility's required condition at all times between inspections. In other words, exceeding these conditions at any time between inspections and/or maintenance does not automatically constitute a violation of these standards. However, based upon inspection observations, the inspection and maintenance schedules shall be adjusted to minimize the length of time that a facility is in a condition that requires a maintenance action. Table I-D-1. Maintenance Standards No. 1 – Detention Ponds Maintenance Component Defect Conditions When Maintenance Is Needed Results Expected When Maintenance Is Performed Trash & Debris Any trash and debris which exceed 5 cubic feet per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size garbage can). In general, there should be no visual evidence of dumping. If less than threshold all trash and debris will be removed as part of next scheduled maintenance. Trash and debris cleared from site. Poisonous Vegetation and noxious weeds Any poisonous or nuisance vegetation which may constitute a hazard to maintenance personnel or the public. Any evidence of noxious weeds as defined by State or local regulations. (Apply requirements of adopted IPM policies for the use of herbicides). No danger of poisonous vegetation where maintenance personnel or the public might normally be. (Coordinate with local health department) Complete eradication of noxious weeds may not be possible. Compliance with State or local eradication policies required Contaminants and Pollution Any evidence of oil, gasoline, contaminants or other pollutants (Coordinate removal/cleanup with local water quality response agency). No contaminants or pollutants present General Rodent Holes Any evidence of rodent holes if facility is acting as a dam or berm, or any evidence of water piping through dam or berm via rodent holes. Rodents destroyed and dam or berm repaired. (Coordinate with local health department; coordinate with Ecology Dam Safety Office if pond exceeds 10 acre-feet.) 68 245 of 628 S U R F A C E W A T E R M A N A G E M E N T M A N U A L N O V E M B E R 2 0 0 9 Maintenance Standards for Volume I Drainage Facilities Appendix D 56 No. 1 – Detention Ponds Maintenance Component Defect Conditions When Maintenance Is Needed Results Expected When Maintenance Is Performed Beaver Dams Dam results in change or function of the facility. Facility is returned to design function. (Coordinate trapping of beavers and removal of dams with appropriate permitting agencies) Insects When insects such as wasps and hornets interfere with maintenance activities. Insects destroyed or removed from site. Apply insecticides in compliance with adopted IPM policies General Tree Growth and Hazard Trees Tree growth does not allow maintenance access or interferes with maintenance activity (i.e., slope mowing, silt removal, vactoring, or equipment movements). If trees are not interfering with access or maintenance, do not remove If trees are dead, diseased, or dying. (Use a certified Arborist to determine health of tree or removal requirements) Trees do not hinder maintenance activities. Harvested trees should be recycled into mulch or other beneficial uses (e.g., alders for firewood). Remove hazard trees Side Slopes of Pond Erosion Eroded damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Any erosion observed on a compacted berm embankment. Slopes should be stabilized using appropriate erosion control measure(s); e.g., rock reinforcement, planting of grass, compaction. If erosion is occurring on compacted berms a licensed civil engineer should be consulted to resolve source of erosion. Sediment Accumulated sediment that exceeds 10% of the designed pond depth unless otherwise specified or affects inletting or outletting condition of the facility. Sediment cleaned out to designed pond shape and depth; pond reseeded if necessary to control erosion. Storage Area Liner (If Applicable) Liner is visible and has more than three 1/4-inch holes in it. Liner repaired or replaced. Liner is fully covered. 69 246 of 628 S U R F A C E W A T E R M A N A G E M E N T M A N U A L N O V E M B E R 2 0 0 9 Maintenance Standards for Volume I Drainage Facilities Appendix D 57 No. 1 – Detention Ponds Maintenance Component Defect Conditions When Maintenance Is Needed Results Expected When Maintenance Is Performed Settlements Any part of berm which has settled 4 inches lower than the design elevation. If settlement is apparent, measure berm to determine amount of settlement. Settling can be an indication of more severe problems with the berm or outlet works. A licensed civil engineer should be consulted to determine the source of the settlement. Dike is built back to the design elevation. Pond Berms (Dikes) Piping Discernable water flow through pond berm. Ongoing erosion with potential for erosion to continue. (Recommend a Geotechnical engineer be called in to inspect and evaluate condition and recommend repair of condition. Piping eliminated. Erosion potential resolved. Tree Growth Tree growth on emergency spillways creates blockage problems and may cause failure of the berm due to uncontrolled overtopping. Tree growth on berms over 4 feet in height may lead to piping through the berm which could lead to failure of the berm. Trees should be removed. If root system is small (base less than 4 inches) the root system may be left in place. Otherwise the roots should be removed and the berm restored. A licensed civil engineer should be consulted for proper berm/spillway restoration. Emergency Overflow/ Spillway and Berms over 4 feet in height. Piping Discernable water flow through pond berm. Ongoing erosion with potential for erosion to continue. (Recommend a Geotechnical engineer be called in to inspect and evaluate condition and recommend repair of condition. Piping eliminated. Erosion potential resolved. Emergency Overflow/ Spillway Only one layer of rock exists above native soil in area five square feet or larger, or any exposure of native soil at the top of out flow path of spillway. (Rip-rap on inside slopes need not be replaced.) Rocks and pad depth are restored to design standards. Emergency Overflow/ Spillway Erosion See “Side Slopes of Pond” 70 247 of 628 S U R F A C E W A T E R M A N A G E M E N T M A N U A L N O V E M B E R 2 0 0 9 Maintenance Standards for Volume I Drainage Facilities Appendix D 60 No. 4 – Control Structure/Flow Restrictor Maintenance Component Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed Trash and Debris (Includes Sediment) Material exceeds 25% of sump depth or 1 foot below orifice plate. Control structure orifice is not blocked. All trash and debris removed. Structure is not securely attached to manhole wall. Structure securely attached to wall and outlet pipe. Structure is not in upright position (allow up to 10% from plumb). Structure in correct position. Connections to outlet pipe are not watertight and show signs of rust. Connections to outlet pipe are water tight; structure repaired or replaced and works as designed. General Structural Damage Any holes--other than designed holes--in the structure. Structure has no holes other than designed holes. Cleanout gate is not watertight, is missing, or is left open. Gate is watertight, works as designed, and is left closed. Gate cannot be moved up and down by one maintenance person. Gate moves up and down easily and is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Cleanout Gate Damaged or Missing Gate is rusted over 50% of its surface area. Gate is repaired or replaced to meet design standards. Damaged or Missing Control device is not working properly due to missing, out of place, or bent orifice plate. Plate is in place and works as designed. Orifice Plate Obstructions Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Overflow Pipe Obstructions Any trash or debris blocking (or having the potential of blocking) the overflow pipe. Pipe is free of all obstructions and works as designed. Manhole See “Closed Detention Systems” (No. 3). See “Closed Detention Systems” (No. 3). See “Closed Detention Systems” (No. 3). Catch Basin See “Catch Basins” (No. 5). See “Catch Basins” (No. 5). See “Catch Basins” (No. 5). 71 248 of 628 72 249 of 628 73 250 of 628 S U R F A C E W A T E R M A N A G E M E N T M A N U A L N O V E M B E R 2 0 0 9 Maintenance Standards for Volume I Drainage Facilities Appendix D 63 No. 7 – Energy Dissipaters Maintenance Components Defect Conditions When Maintenance is Needed Results Expected When Maintenance is Performed External: Missing or Moved Rock Only one layer of rock exists above native soil in area five square feet or larger, or any exposure of native soil. Rock pad replaced to design standards. Rock Pad Erosion Soil erosion in or adjacent to rock pad. Rock pad replaced to design standards. Pipe Plugged with Sediment Accumulated sediment that exceeds 20% of the design depth. Pipe cleaned/flushed so that it matches design. Not Discharging Water Properly Visual evidence of water discharging at concentrated points along trench (normal condition is a “sheet flow” of water along trench). Intent is to prevent erosion damage. Trench redesigned or rebuilt to standards. Perforations Plugged. Over 1/2 of perforations in pipe are plugged with debris and sediment. Perforated pipe cleaned or replaced. Water Flows Out Top of “Distributor” Catch Basin. Maintenance person observes or receives credible report of water flowing out during any storm less than the design storm or its causing or appears likely to cause damage. Facility rebuilt or redesigned to standards. Dispersion Trench Receiving Area Over-Saturated Water in receiving area is causing or has potential of causing landslide problems. No danger of landslides. Internal: Worn or Damaged Post, Baffles, Side of Chamber Structure dissipating flow deteriorates to 1/2 of original size or any concentrated worn spot exceeding one square foot which would make structure unsound. Structure replaced to design standards. Manhole/Ch amber Other Defects See “Catch Basins” (No. 5). See “Catch Basins” (No. 5). 74 251 of 628 S U R F A C E W A T E R M A N A G E M E N T M A N U A L N O V E M B E R 2 0 0 9 Maintenance Standards for Volume I Drainage Facilities Appendix D 67 No. 11 – Wetponds Maintenance Component Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed Water level First cell is empty, does not hold water. Line the first cell to maintain at least 4 feet of water. Although the second cell may drain, the first cell must remain full to control turbulence of the incoming flow and reduce sediment resuspension. Trash and Debris Accumulation that exceeds 1 CF per 1000-SF of pond area. Trash and debris removed from pond. Inlet/Outlet Pipe Inlet/Outlet pipe clogged with sediment and/or debris material. No clogging or blockage in the inlet and outlet piping. Sediment Accumulati on in Pond Bottom Sediment accumulations in pond bottom that exceeds the depth of sediment zone plus 6-inches, usually in the first cell. Sediment removed from pond bottom. Oil Sheen on Water Prevalent and visible oil sheen. Oil removed from water using oil-absorbent pads or vactor truck. Source of oil located and corrected. If chronic low levels of oil persist, plant wetland plants such as Juncus effusus (soft rush) which can uptake small concentrations of oil. Erosion Erosion of the pond’s side slopes and/or scouring of the pond bottom, that exceeds 6-inches, or where continued erosion is prevalent. Slopes stabilized using proper erosion control measures and repair methods. Settlement of Pond Dike/Berm Any part of these components that has settled 4-inches or lower than the design elevation, or inspector determines dike/berm is unsound. Dike/berm is repaired to specifications. Internal Berm Berm dividing cells should be level. Berm surface is leveled so that water flows evenly over entire length of berm. General Overflow Spillway Rock is missing and soil is exposed at top of spillway or outside slope. Rocks replaced to specifications. 75 252 of 628 76 Attachment B Stormwater Pollution Prevention Plan 253 of 628 77 A Stormwater Pollution Prevention Plan will be prepared with the Civil FAC plans. 254 of 628 78 Attachment C Hydraulic/Hydrologic Analysis and Modeling Results 255 of 628 79256 of 628 80257 of 628 81258 of 628 82259 of 628 83260 of 628 84261 of 628 85262 of 628 86263 of 628 87264 of 628 88265 of 628 89266 of 628 WWHM2012 PROJECT REPORT 90 267 of 628 18355-south pond-alt2 1/18/2019 10:14:04 AM Page 2 General Model Information Project Name:18355-south pond-alt2 Site Name: Site Address: City: Report Date:1/18/2019 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2018/07/12 Version:4.2.15 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 91 268 of 628 18355-south pond-alt2 1/18/2019 10:14:04 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 13.76 Pervious Total 13.76 Impervious Land Use acre Impervious Total 0 Basin Total 13.76 Element Flows To: Surface Interflow Groundwater 92 269 of 628 18355-south pond-alt2 1/18/2019 10:14:04 AM Page 4 Offsite 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 1.56 Pervious Total 1.56 Impervious Land Use acre ROADS FLAT 0.25 Impervious Total 0.25 Basin Total 1.81 Element Flows To: Surface Interflow Groundwater 93 270 of 628 18355-south pond-alt2 1/18/2019 10:14:04 AM Page 5 Offsite 2 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 0.08 Pervious Total 0.08 Impervious Land Use acre Impervious Total 0 Basin Total 0.08 Element Flows To: Surface Interflow Groundwater 94 271 of 628 18355-south pond-alt2 1/18/2019 10:14:04 AM Page 6 Offsite 3 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 2.17 Pervious Total 2.17 Impervious Land Use acre Impervious Total 0 Basin Total 2.17 Element Flows To: Surface Interflow Groundwater 95 272 of 628 18355-south pond-alt2 1/18/2019 10:14:04 AM Page 7 Offsite 4 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.58 Pervious Total 0.58 Impervious Land Use acre ROADS FLAT 0.57 Impervious Total 0.57 Basin Total 1.15 Element Flows To: Surface Interflow Groundwater 96 273 of 628 18355-south pond-alt2 1/18/2019 10:14:04 AM Page 8 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 2.77 C, Lawn, Steep 1.88 C, Forest, Mod 0.37 Pervious Total 5.02 Impervious Land Use acre ROADS FLAT 8.74 Impervious Total 8.74 Basin Total 13.76 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 1 Trapezoidal Pond 1 97 274 of 628 18355-south pond-alt2 1/18/2019 10:14:05 AM Page 9 Offsite 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 1.56 Pervious Total 1.56 Impervious Land Use acre ROADS FLAT 0.25 Impervious Total 0.25 Basin Total 1.81 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 1 Trapezoidal Pond 1 98 275 of 628 18355-south pond-alt2 1/18/2019 10:14:05 AM Page 10 Offsite 2 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 0.08 Pervious Total 0.08 Impervious Land Use acre Impervious Total 0 Basin Total 0.08 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 1 Trapezoidal Pond 1 99 276 of 628 18355-south pond-alt2 1/18/2019 10:14:05 AM Page 11 Offsite 3 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 2.17 Pervious Total 2.17 Impervious Land Use acre Impervious Total 0 Basin Total 2.17 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 1 Trapezoidal Pond 1 100 277 of 628 18355-south pond-alt2 1/18/2019 10:14:05 AM Page 12 Offsite 4 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.58 Pervious Total 0.58 Impervious Land Use acre ROADS FLAT 0.57 Impervious Total 0.57 Basin Total 1.15 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 1 Trapezoidal Pond 1 101 278 of 628 18355-south pond-alt2 1/18/2019 10:14:05 AM Page 13 Routing Elements Predeveloped Routing 102 279 of 628 18355-south pond-alt2 1/18/2019 10:14:05 AM Page 14 Mitigated Routing Trapezoidal Pond 1 Bottom Length:455.00 ft. Bottom Width:80.00 ft. Depth:6 ft. Volume at riser head:3.9497 acre-feet. Side slope 1:3 To 1 Side slope 2:3 To 1 Side slope 3:3 To 1 Side slope 4:3 To 1 Discharge Structure Riser Height:4 ft. Riser Diameter:18 in. Notch Type:Rectangular Notch Width:0.040 ft. Notch Height:1.650 ft. Orifice 1 Diameter:3 in.Elevation:0 ft. Element Flows To: Outlet 1 Outlet 2 Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.835 0.000 0.000 0.000 0.0667 0.840 0.055 0.063 0.000 0.1333 0.845 0.112 0.089 0.000 0.2000 0.850 0.168 0.109 0.000 0.2667 0.855 0.225 0.126 0.000 0.3333 0.860 0.282 0.141 0.000 0.4000 0.865 0.340 0.154 0.000 0.4667 0.870 0.398 0.166 0.000 0.5333 0.875 0.456 0.178 0.000 0.6000 0.880 0.514 0.189 0.000 0.6667 0.885 0.573 0.199 0.000 0.7333 0.890 0.632 0.209 0.000 0.8000 0.895 0.692 0.218 0.000 0.8667 0.900 0.752 0.227 0.000 0.9333 0.905 0.812 0.235 0.000 1.0000 0.910 0.872 0.244 0.000 1.0667 0.915 0.933 0.252 0.000 1.1333 0.920 0.994 0.260 0.000 1.2000 0.925 1.056 0.267 0.000 1.2667 0.930 1.118 0.274 0.000 1.3333 0.935 1.180 0.282 0.000 1.4000 0.940 1.242 0.289 0.000 1.4667 0.945 1.305 0.295 0.000 1.5333 0.950 1.368 0.302 0.000 1.6000 0.955 1.432 0.308 0.000 1.6667 0.960 1.496 0.315 0.000 1.7333 0.965 1.560 0.321 0.000 1.8000 0.971 1.625 0.327 0.000 1.8667 0.976 1.690 0.333 0.000 1.9333 0.981 1.755 0.339 0.000 2.0000 0.986 1.820 0.345 0.000 2.0667 0.991 1.886 0.351 0.000 103 280 of 628 18355-south pond-alt2 1/18/2019 10:14:05 AM Page 15 2.1333 0.996 1.953 0.356 0.000 2.2000 1.001 2.019 0.362 0.000 2.2667 1.006 2.086 0.367 0.000 2.3333 1.012 2.153 0.373 0.000 2.4000 1.017 2.221 0.379 0.000 2.4667 1.022 2.289 0.388 0.000 2.5333 1.027 2.357 0.398 0.000 2.6000 1.032 2.426 0.409 0.000 2.6667 1.038 2.495 0.421 0.000 2.7333 1.043 2.565 0.433 0.000 2.8000 1.048 2.634 0.445 0.000 2.8667 1.053 2.704 0.457 0.000 2.9333 1.058 2.775 0.470 0.000 3.0000 1.064 2.845 0.483 0.000 3.0667 1.069 2.917 0.496 0.000 3.1333 1.074 2.988 0.510 0.000 3.2000 1.079 3.060 0.523 0.000 3.2667 1.085 3.132 0.536 0.000 3.3333 1.090 3.205 0.550 0.000 3.4000 1.095 3.277 0.565 0.000 3.4667 1.101 3.351 0.580 0.000 3.5333 1.106 3.424 0.596 0.000 3.6000 1.111 3.498 0.612 0.000 3.6667 1.116 3.572 0.628 0.000 3.7333 1.122 3.647 0.645 0.000 3.8000 1.127 3.722 0.721 0.000 3.8667 1.132 3.797 0.743 0.000 3.9333 1.138 3.873 0.764 0.000 4.0000 1.143 3.949 0.786 0.000 4.0667 1.149 4.026 1.064 0.000 4.1333 1.154 4.102 1.566 0.000 4.2000 1.159 4.180 2.203 0.000 4.2667 1.165 4.257 2.926 0.000 4.3333 1.170 4.335 3.689 0.000 4.4000 1.175 4.413 4.442 0.000 4.4667 1.181 4.492 5.140 0.000 4.5333 1.186 4.571 5.742 0.000 4.6000 1.192 4.650 6.223 0.000 4.6667 1.197 4.730 6.580 0.000 4.7333 1.203 4.810 6.843 0.000 4.8000 1.208 4.890 7.171 0.000 4.8667 1.213 4.971 7.434 0.000 4.9333 1.219 5.052 7.687 0.000 5.0000 1.224 5.133 7.931 0.000 5.0667 1.230 5.215 8.167 0.000 5.1333 1.235 5.297 8.395 0.000 5.2000 1.241 5.380 8.618 0.000 5.2667 1.246 5.463 8.834 0.000 5.3333 1.252 5.546 9.045 0.000 5.4000 1.257 5.630 9.250 0.000 5.4667 1.263 5.714 9.451 0.000 5.5333 1.268 5.798 9.647 0.000 5.6000 1.274 5.883 9.840 0.000 5.6667 1.279 5.968 10.02 0.000 5.7333 1.285 6.054 10.21 0.000 5.8000 1.290 6.139 10.39 0.000 5.8667 1.296 6.226 10.57 0.000 5.9333 1.302 6.312 10.74 0.000 104 281 of 628 18355-south pond-alt2 1/18/2019 10:14:05 AM Page 16 6.0000 1.307 6.399 10.91 0.000 6.0667 1.313 6.487 11.08 0.000 105 282 of 628 18355-south pond-alt2 1/18/2019 10:14:05 AM Page 17 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:18.15 Total Impervious Area:0.82 Mitigated Landuse Totals for POC #1 Total Pervious Area:9.41 Total Impervious Area:9.56 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.768363 5 year 1.178764 10 year 1.488328 25 year 1.922419 50 year 2.277188 100 year 2.659102 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.397314 5 year 0.5972 10 year 0.765847 25 year 1.027085 50 year 1.261436 100 year 1.53421 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 1.114 0.312 1950 1.133 0.408 1951 1.351 1.167 1952 0.556 0.274 1953 0.422 0.319 1954 0.589 0.365 1955 0.888 0.377 1956 0.819 0.462 1957 0.851 0.356 1958 0.660 0.369 106 283 of 628 18355-south pond-alt2 1/18/2019 10:14:50 AM Page 18 1959 0.572 0.327 1960 1.112 0.659 1961 0.647 0.356 1962 0.388 0.262 1963 0.616 0.356 1964 0.756 0.332 1965 0.689 0.385 1966 0.529 0.325 1967 1.248 0.374 1968 0.772 0.330 1969 0.695 0.315 1970 0.653 0.326 1971 0.748 0.379 1972 1.058 0.531 1973 0.531 0.370 1974 0.733 0.376 1975 0.988 0.362 1976 0.717 0.371 1977 0.322 0.281 1978 0.565 0.364 1979 0.460 0.262 1980 1.547 0.682 1981 0.561 0.324 1982 1.219 0.521 1983 0.755 0.374 1984 0.513 0.296 1985 0.381 0.305 1986 1.097 0.489 1987 1.087 0.558 1988 0.434 0.306 1989 0.333 0.288 1990 2.692 0.663 1991 1.598 0.716 1992 0.660 0.370 1993 0.531 0.316 1994 0.271 0.246 1995 0.728 0.397 1996 1.714 1.329 1997 1.246 1.360 1998 0.544 0.312 1999 1.690 0.565 2000 0.657 0.366 2001 0.366 0.259 2002 0.750 0.492 2003 1.086 0.309 2004 1.106 0.798 2005 0.842 0.382 2006 0.840 0.370 2007 2.149 1.887 2008 2.220 1.317 2009 1.195 0.479 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 2.6917 1.8867 2 2.2198 1.3604 3 2.1486 1.3295 107 284 of 628 18355-south pond-alt2 1/18/2019 10:14:50 AM Page 19 4 1.7137 1.3173 5 1.6905 1.1665 6 1.5982 0.7981 7 1.5470 0.7156 8 1.3506 0.6817 9 1.2484 0.6627 10 1.2462 0.6589 11 1.2188 0.5649 12 1.1954 0.5577 13 1.1328 0.5309 14 1.1143 0.5212 15 1.1122 0.4916 16 1.1061 0.4892 17 1.0966 0.4789 18 1.0870 0.4617 19 1.0858 0.4078 20 1.0579 0.3972 21 0.9884 0.3851 22 0.8884 0.3818 23 0.8510 0.3788 24 0.8423 0.3772 25 0.8402 0.3760 26 0.8190 0.3741 27 0.7725 0.3736 28 0.7562 0.3714 29 0.7552 0.3705 30 0.7499 0.3702 31 0.7481 0.3698 32 0.7327 0.3687 33 0.7276 0.3659 34 0.7173 0.3654 35 0.6951 0.3645 36 0.6886 0.3616 37 0.6602 0.3564 38 0.6596 0.3564 39 0.6568 0.3559 40 0.6530 0.3321 41 0.6474 0.3305 42 0.6162 0.3270 43 0.5888 0.3257 44 0.5725 0.3250 45 0.5654 0.3235 46 0.5613 0.3186 47 0.5556 0.3165 48 0.5445 0.3151 49 0.5313 0.3124 50 0.5305 0.3121 51 0.5288 0.3085 52 0.5127 0.3058 53 0.4600 0.3052 54 0.4339 0.2960 55 0.4219 0.2884 56 0.3881 0.2813 57 0.3808 0.2743 58 0.3658 0.2624 59 0.3328 0.2620 60 0.3222 0.2586 61 0.2706 0.2457 108 285 of 628 18355-south pond-alt2 1/18/2019 10:14:50 AM Page 20 109 286 of 628 18355-south pond-alt2 1/18/2019 10:14:50 AM Page 21 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.3842 9894 7852 79 Pass 0.4033 8748 6564 75 Pass 0.4224 7790 5689 73 Pass 0.4415 6953 4964 71 Pass 0.4607 6196 4325 69 Pass 0.4798 5561 3767 67 Pass 0.4989 5024 3294 65 Pass 0.5180 4507 2845 63 Pass 0.5372 4060 2301 56 Pass 0.5563 3692 1961 53 Pass 0.5754 3330 1706 51 Pass 0.5945 3018 1527 50 Pass 0.6136 2731 1339 49 Pass 0.6328 2479 1113 44 Pass 0.6519 2246 910 40 Pass 0.6710 2023 832 41 Pass 0.6901 1822 779 42 Pass 0.7092 1642 731 44 Pass 0.7284 1479 655 44 Pass 0.7475 1332 518 38 Pass 0.7666 1203 411 34 Pass 0.7857 1084 243 22 Pass 0.8048 995 213 21 Pass 0.8240 923 204 22 Pass 0.8431 839 187 22 Pass 0.8622 769 178 23 Pass 0.8813 711 161 22 Pass 0.9005 643 152 23 Pass 0.9196 586 148 25 Pass 0.9387 532 142 26 Pass 0.9578 479 133 27 Pass 0.9769 428 124 28 Pass 0.9961 373 118 31 Pass 1.0152 326 112 34 Pass 1.0343 286 105 36 Pass 1.0534 246 97 39 Pass 1.0725 210 85 40 Pass 1.0917 183 77 42 Pass 1.1108 162 69 42 Pass 1.1299 141 67 47 Pass 1.1490 127 63 49 Pass 1.1682 114 55 48 Pass 1.1873 102 54 52 Pass 1.2064 91 50 54 Pass 1.2255 82 49 59 Pass 1.2446 67 44 65 Pass 1.2638 55 43 78 Pass 1.2829 49 39 79 Pass 1.3020 39 35 89 Pass 1.3211 33 29 87 Pass 1.3402 29 25 86 Pass 1.3594 27 18 66 Pass 1.3785 24 15 62 Pass 110 287 of 628 18355-south pond-alt2 1/18/2019 10:14:50 AM Page 22 1.3976 24 15 62 Pass 1.4167 24 15 62 Pass 1.4359 21 14 66 Pass 1.4550 20 13 65 Pass 1.4741 19 13 68 Pass 1.4932 16 13 81 Pass 1.5123 15 12 80 Pass 1.5315 14 12 85 Pass 1.5506 12 11 91 Pass 1.5697 11 10 90 Pass 1.5888 9 9 100 Pass 1.6079 8 8 100 Pass 1.6271 8 8 100 Pass 1.6462 8 7 87 Pass 1.6653 8 7 87 Pass 1.6844 8 7 87 Pass 1.7035 7 6 85 Pass 1.7227 6 6 100 Pass 1.7418 6 6 100 Pass 1.7609 6 5 83 Pass 1.7800 6 4 66 Pass 1.7992 6 4 66 Pass 1.8183 5 4 80 Pass 1.8374 5 4 80 Pass 1.8565 5 2 40 Pass 1.8756 5 2 40 Pass 1.8948 5 0 0 Pass 1.9139 5 0 0 Pass 1.9330 5 0 0 Pass 1.9521 5 0 0 Pass 1.9712 5 0 0 Pass 1.9904 5 0 0 Pass 2.0095 5 0 0 Pass 2.0286 4 0 0 Pass 2.0477 4 0 0 Pass 2.0669 4 0 0 Pass 2.0860 4 0 0 Pass 2.1051 4 0 0 Pass 2.1242 4 0 0 Pass 2.1433 4 0 0 Pass 2.1625 3 0 0 Pass 2.1816 3 0 0 Pass 2.2007 3 0 0 Pass 2.2198 3 0 0 Pass 2.2389 2 0 0 Pass 2.2581 2 0 0 Pass 2.2772 1 0 0 Pass 111 288 of 628 18355-south pond-alt2 1/18/2019 10:14:50 AM Page 23 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:1.4519 acre-feet On-line facility target flow:1.5573 cfs. Adjusted for 15 min:1.5573 cfs. Off-line facility target flow:0.8701 cfs. Adjusted for 15 min:0.8701 cfs. 112 289 of 628 18355-south pond-alt2 1/18/2019 10:14:50 AM Page 24 LID Report 113 290 of 628 18355-south pond-alt2 1/18/2019 10:15:22 AM Page 25 POC 2 POC #2 was not reported because POC must exist in both scenarios and both scenarios must have been run. 114 291 of 628 18355-south pond-alt2 1/18/2019 10:15:22 AM Page 26 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 115 292 of 628 18355-south pond-alt2 1/18/2019 10:15:22 AM Page 27 Appendix Predeveloped Schematic 116 293 of 628 18355-south pond-alt2 1/18/2019 10:15:24 AM Page 28 Mitigated Schematic 117 294 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 29 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 18355-south pond-alt2.wdm MESSU 25 Pre18355-south pond-alt2.MES 27 Pre18355-south pond-alt2.L61 28 Pre18355-south pond-alt2.L62 30 POC18355-south pond-alt21.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 11 IMPLND 1 PERLND 17 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 11 C, Forest, Mod 1 1 1 1 27 0 17 C, Lawn, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 11 0 0 1 0 0 0 0 0 0 0 0 0 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR 118 295 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 30 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 11 0 0 4 0 0 0 0 0 0 0 0 0 1 9 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 11 0 0 0 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 11 0 4.5 0.08 400 0.1 0.5 0.996 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 11 0 0 2 2 0 0 0 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 11 0.2 0.5 0.35 6 0.5 0.7 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 11 0 0 0 0 2.5 1 0 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 119 296 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 31 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 11 13.76 COPY 501 12 PERLND 11 13.76 COPY 501 13 Offsite 1*** PERLND 11 1.56 COPY 501 12 PERLND 11 1.56 COPY 501 13 IMPLND 1 0.25 COPY 501 15 Offsite 2*** PERLND 11 0.08 COPY 501 12 PERLND 11 0.08 COPY 501 13 Offsite 3*** PERLND 11 2.17 COPY 501 12 PERLND 11 2.17 COPY 501 13 Offsite 4*** PERLND 17 0.58 COPY 501 12 PERLND 17 0.58 COPY 501 13 IMPLND 1 0.57 COPY 501 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 120 297 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 32 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN 121 298 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 33 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 18355-south pond-alt2.wdm MESSU 25 Mit18355-south pond-alt2.MES 27 Mit18355-south pond-alt2.L61 28 Mit18355-south pond-alt2.L62 30 POC18355-south pond-alt21.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 PERLND 18 PERLND 11 IMPLND 1 PERLND 17 RCHRES 1 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Trapezoidal Pond 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 18 C, Lawn, Steep 1 1 1 1 27 0 11 C, Forest, Mod 1 1 1 1 27 0 17 C, Lawn, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 122 299 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 34 16 0 0 1 0 0 0 0 0 0 0 0 0 18 0 0 1 0 0 0 0 0 0 0 0 0 11 0 0 1 0 0 0 0 0 0 0 0 0 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 18 0 0 4 0 0 0 0 0 0 0 0 0 1 9 11 0 0 4 0 0 0 0 0 0 0 0 0 1 9 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 18 0 0 0 0 0 0 0 0 0 0 0 11 0 0 0 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 18 0 4.5 0.03 400 0.15 0.5 0.996 11 0 4.5 0.08 400 0.1 0.5 0.996 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 18 0 0 2 2 0 0 0 11 0 0 2 2 0 0 0 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 18 0.1 0.15 0.25 6 0.3 0.25 11 0.2 0.5 0.35 6 0.5 0.7 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 18 0 0 0 0 2.5 1 0 11 0 0 0 0 2.5 1 0 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** 123 300 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 35 ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 16 2.77 RCHRES 1 2 PERLND 16 2.77 RCHRES 1 3 PERLND 18 1.88 RCHRES 1 2 PERLND 18 1.88 RCHRES 1 3 PERLND 11 0.37 RCHRES 1 2 PERLND 11 0.37 RCHRES 1 3 IMPLND 1 8.74 RCHRES 1 5 Offsite 1*** PERLND 11 1.56 RCHRES 1 2 PERLND 11 1.56 RCHRES 1 3 IMPLND 1 0.25 RCHRES 1 5 Offsite 2*** PERLND 11 0.08 RCHRES 1 2 PERLND 11 0.08 RCHRES 1 3 Offsite 3*** PERLND 11 2.17 RCHRES 1 2 PERLND 11 2.17 RCHRES 1 3 Offsite 4*** PERLND 17 0.58 RCHRES 1 2 PERLND 17 0.58 RCHRES 1 3 IMPLND 1 0.57 RCHRES 1 5 ******Routing****** PERLND 16 2.77 COPY 1 12 PERLND 18 1.88 COPY 1 12 PERLND 11 0.37 COPY 1 12 IMPLND 1 8.74 COPY 1 15 124 301 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 36 PERLND 16 2.77 COPY 1 13 PERLND 18 1.88 COPY 1 13 PERLND 11 0.37 COPY 1 13 PERLND 11 1.56 COPY 1 12 IMPLND 1 0.25 COPY 1 15 PERLND 11 1.56 COPY 1 13 PERLND 11 0.08 COPY 1 12 PERLND 11 0.08 COPY 1 13 PERLND 11 2.17 COPY 1 12 PERLND 11 2.17 COPY 1 13 PERLND 17 0.58 COPY 1 12 IMPLND 1 0.57 COPY 1 15 PERLND 17 0.58 COPY 1 13 RCHRES 1 1 COPY 501 16 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Trapezoidal Pond-005 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.09 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES 125 302 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 37 SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 91 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.835629 0.000000 0.000000 0.066667 0.840545 0.055872 0.063060 0.133333 0.845469 0.112073 0.089181 0.200000 0.850400 0.168602 0.109224 0.266667 0.855339 0.225460 0.126120 0.333333 0.860285 0.282647 0.141007 0.400000 0.865238 0.340165 0.154465 0.466667 0.870198 0.398013 0.166842 0.533333 0.875166 0.456191 0.178361 0.600000 0.880141 0.514702 0.189181 0.666667 0.885124 0.573544 0.199414 0.733333 0.890114 0.632719 0.209147 0.800000 0.895111 0.692226 0.218447 0.866667 0.900116 0.752067 0.227367 0.933333 0.905128 0.812242 0.235950 1.000000 0.910147 0.872751 0.244231 1.066667 0.915174 0.933595 0.252241 1.133333 0.920208 0.994774 0.260004 1.200000 0.925249 1.056289 0.267542 1.266667 0.930298 1.118141 0.274873 1.333333 0.935354 1.180329 0.282014 1.400000 0.940417 1.242855 0.288978 1.466667 0.945488 1.305719 0.295779 1.533333 0.950566 1.368920 0.302426 1.600000 0.955651 1.432461 0.308931 1.666667 0.960744 1.496341 0.315301 1.733333 0.965844 1.560560 0.321545 1.800000 0.970951 1.625120 0.327671 1.866667 0.976066 1.690021 0.333683 1.933333 0.981188 1.755263 0.339590 2.000000 0.986318 1.820846 0.345395 2.066667 0.991455 1.886772 0.351105 2.133333 0.996599 1.953040 0.356723 2.200000 1.001750 2.019652 0.362253 2.266667 1.006909 2.086607 0.367701 2.333333 1.012075 2.153907 0.373069 2.400000 1.017249 2.221551 0.379836 2.466667 1.022430 2.289540 0.388765 2.533333 1.027618 2.357875 0.398802 2.600000 1.032814 2.426556 0.409629 2.666667 1.038017 2.495584 0.421061 2.733333 1.043227 2.564958 0.432972 2.800000 1.048444 2.634681 0.445267 2.866667 1.053669 2.704751 0.457869 2.933333 1.058902 2.775170 0.470715 3.000000 1.064141 2.845938 0.483750 3.066667 1.069388 2.917056 0.496925 3.133333 1.074643 2.988524 0.510199 3.200000 1.079904 3.060342 0.523533 3.266667 1.085174 3.132511 0.536892 3.333333 1.090450 3.205032 0.550243 3.400000 1.095734 3.277905 0.564991 3.466667 1.101025 3.351130 0.580476 3.533333 1.106323 3.424708 0.596254 3.600000 1.111629 3.498640 0.612318 3.666667 1.116942 3.572926 0.628661 3.733333 1.122263 3.647566 0.645274 3.800000 1.127590 3.722561 0.721733 3.866667 1.132926 3.797912 0.743025 3.933333 1.138268 3.873618 0.764662 4.000000 1.143618 3.949681 0.786637 4.066667 1.148975 4.026101 1.064386 4.133333 1.154340 4.102878 1.566176 126 303 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 38 4.200000 1.159712 4.180013 2.203164 4.266667 1.165091 4.257506 2.926480 4.333333 1.170478 4.335359 3.689102 4.400000 1.175871 4.413570 4.442679 4.466667 1.181273 4.492142 5.140371 4.533333 1.186681 4.571074 5.742380 4.600000 1.192097 4.650366 6.223213 4.666667 1.197521 4.730020 6.580269 4.733333 1.202951 4.810036 6.843519 4.800000 1.208389 4.890414 7.171767 4.866667 1.213835 4.971155 7.434290 4.933333 1.219287 5.052259 7.687011 5.000000 1.224747 5.133727 7.930960 5.066667 1.230215 5.215559 8.167000 5.133333 1.235690 5.297756 8.395860 5.200000 1.241172 5.380318 8.618163 5.266667 1.246661 5.463245 8.834447 5.333333 1.252158 5.546539 9.045181 5.400000 1.257662 5.630200 9.250775 5.466667 1.263174 5.714228 9.451590 5.533333 1.268692 5.798623 9.647948 5.600000 1.274219 5.883387 9.840135 5.666667 1.279752 5.968519 10.02841 5.733333 1.285293 6.054021 10.21300 5.800000 1.290841 6.139892 10.39412 5.866667 1.296397 6.226133 10.57196 5.933333 1.301960 6.312745 10.74670 6.000000 1.307530 6.399728 10.91848 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1000 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1001 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 127 304 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 39 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 END MASS-LINK END RUN 128 305 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 40 Predeveloped HSPF Message File 129 306 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 41 Mitigated HSPF Message File 130 307 of 628 18355-south pond-alt2 1/18/2019 10:15:27 AM Page 42 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2019; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com 131 308 of 628 South Pond - Detention VolumeElevationTotal AreaVolumeSum Volume39036348003914075138549.538549.53924524842999.5815493934983447541129090393.855374744021.925173111.925393.8658170559.585173671.51394586828179.64181851.154.1747283.95NEEDED3956379761239.5243090.65396132309 of 628 Water QualityElevationTotal AreaVolumeSum Volume38619630003872349321561.521561.53882753825515.54707738931764296517672839036348340561107842.5432511.45ac-ft required133310 of 628 134 311 of 628 Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/14/2018 Page 1 of 352396605239710523976052398105239860523991052399605239660523971052397605239810523986052399105239960555070555120555170555220555270555320555370555420555470555520 555070 555120 555170 555220 555270 555320 555370 555420 555470 555520 47° 18' 39'' N 122° 16' 17'' W47° 18' 39'' N122° 15' 54'' W47° 18' 28'' N 122° 16' 17'' W47° 18' 28'' N 122° 15' 54'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 100 200 400 600 Feet 0 30 60 120 180 Meters Map Scale: 1:2,230 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. 135 312 of 628 MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: King County Area, Washington Survey Area Data: Version 14, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 8, 2014—Jul 15, 2014 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/14/2018 Page 2 of 3136 313 of 628 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI AgC Alderwood gravelly sandy loam, 8 to 15 percent slopes 23.2 100.0% Totals for Area of Interest 23.2 100.0% Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/14/2018 Page 3 of 3 137 'C' 314 of 628 Listing ID: 7485 Main Listing Information Listing ID: 7485 2014 Category: 5 Waterbody Name: MILL CREEK 2012 Category: 5 Medium: Water 2008 Category: 5 Parameter: Bacteria 2004 Category: 5 WQI Project: None Assigned On 1998 303(d) List?: Y Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 17110013002282 Location Identification Counties: King Waterbody ID (WBID): None Assigned Town/Range/Section (Legacy): 22N-4E-25 WRIA: 9 - Duwamish-Green Waterbody Class: RA Basis Location ID: [KCM-A315] -- In water year 2009, 1 of 3 sample values (33%) showed an excursion of the % criterion for this waterbody (200 cfu/100mL). Fewer than five samples were available, therefore a geometric mean was not calculated for this period. Location ID: [KCM-A315] -- In water year 2008, 3 of 12 sample values (25%) showed an excursion of the % criterion for this waterbody (200 cfu/100mL). The geometric mean of 52.2 does not exceed the geometric mean criterion (100 cfu/100mL). Location ID: [KCM-A315] -- In water year 2007, 4 of 11 sample values (36%) showed an excursion of the % criterion for this waterbody (200 cfu/100mL). The geometric mean of 69.2 does not exceed the geometric mean criterion (100 cfu/100mL). Location ID: [KCM-A315] -- In water year 2006, 6 of 13 sample values (46%) showed an excursion of the % criterion for this waterbody (200 cfu/100mL). The geometric mean of 253.4 exceeds the geometric mean criterion (100 cfu/100mL). Location ID: [KCM-A315] -- In water year 2005, 4 of 13 sample values (31%) showed an excursion of the % criterion for this waterbody (200 cfu/100mL). The geometric mean of 150.4 exceeds the geometric mean criterion (100 cfu/100mL). Location ID: [KCM-A315] -- In water year 2004, 6 of 12 sample values (50%) showed an excursion of the % criterion for this waterbody (200 cfu/100mL). The geometric mean of 110.2 exceeds the geometric mean criterion (100 cfu/100mL). King County unpublished data from station A315 (Hill Creek RM 0.3) show standards were not met each year in samples collected between 1998 and 2002. King County, 1993, 9 excursions beyond the upper criterion at station 201 (RM 0.2) during 1992 and 1993. King County, 1993, 12 excursions beyond the upper criterion at station 302 (RM 1.0) during 1992 and 1993. King County, 1993, 12 excursions beyond the upper criterion at station 303 (RM 1.4) during 1992 Page 1 of 2Print Approved Listing 1/17/2019https://fortress.wa.gov/ecy/approvedwqa/ApprovedPrintListing.aspx?LISTING_ID=7485 138 315 of 628 and 1993. King County, 1993, 6 excursions beyond the upper criterion at station 304 (RM 2.2) during 1992 and 1993. King County, 1993, 6 excursions beyond the upper criterion at station 305 (RM 7.5) during 1992 and 1993. Remarks Remark Modified By Modified On Visibility Combined Listing: Listing IDs 15820, 15817, 15815, 7486 were rolled into this listing Chad Brown 9/24/2015 Public Policy 1-11 was revised in July 2012 to specify that bacteria is assessed according to water year (Oct-Sept 30) from the previous assessment period of calendar year. the water water assessment is only applied to newly assessed data. Therefore, this listing contains data assessed by both water year and calendar year. Jessica Archer 10/1/2014 Public This listing contains E.coli data. E. coli is a subset of Fecal coliform bacteria therefore E.coli levels above the Fecal coliform standard can be used to infer an exceedance of this water quality standard. Jessica Archer 10/1/2014 Public Impairment was determined by exceedance of the geometric mean criterion in water year(s) 2006, 2005, and2004, and the percent criterion in water year(s) 2009, 2008, 2007, 2006, 2005, 2004. Jessica Archer 10/1/2014 Public EIM User Study ID:User Location ID: KCstrm-1 KCM-A315 Print Page 2 of 2Print Approved Listing 1/17/2019https://fortress.wa.gov/ecy/approvedwqa/ApprovedPrintListing.aspx?LISTING_ID=7485 139 316 of 628 Listing ID: 70175 Main Listing Information Listing ID: 70175 2014 Category: 5 Waterbody Name: HILL (MILL) CREEK 2012 Category: 3 Medium: Other 2008 Category: 3 Parameter: Bioassessment 2004 Category: 3 WQI Project: None Assigned On 1998 303(d) List?: N Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 17110013002282 Location Identification Counties: King Waterbody ID (WBID): None Assigned Town/Range/Section (Legacy): 21N-4E-14 WRIA: 9 - Duwamish-Green Waterbody Class: None Assigned Basis Location ID [09MIL0340] - the Benthic Index of Biotic Integrity (B-IBI) score was 26 in 2006, 28 in 2007, 24 in 2009, 24 in 2010. Location ID [09MIL0390] - the Benthic Index of Biotic Integrity (B-IBI) score was 24 in 2006, 30 in 2007, 34 in 2008, 30 in 2009, 26 in 2010. Location ID [09MIL0497] was sampled by King County - the Benthic Index of Biotic Integrity (B-IBI) score was 10 in 2006 Remarks Remark Modified By Modified On Visibility The source of the benthic macroinvertebrate community data and associated B-IBI scores is the Puget Sound Stream Benthos database, which is maintained by King County. Patrick Lizon 12/22/2015 Private The listing has been reassessed under the current Policy 1-11 and has been moved from Category 3 to Category 5 based on new data. Curtis Cooper 8/12/2015 Private The listing has been placed in Category 5 because the two most recent data points indicate that biological integrity is degraded or because two or more B-IBI/RIVPACS data points in the most recent five data points indicate biological degradation and the scores do not qualify for Category 1 or Category 2. A B-IBI score ≤ 27 and a RIVPACS score less than 0.73 indicates degraded biological integrity. Curtis Cooper 8/12/2015 Public EIM No EIM Records Entered Print Page 1 of 1Print Approved Listing 1/17/2019https://fortress.wa.gov/ecy/approvedwqa/ApprovedPrintListing.aspx?LISTING_ID=70175 140 317 of 628 Listing ID: 7488 Main Listing Information Listing ID: 7488 2014 Category: 5 Waterbody Name: HILL (MILL) CREEK 2012 Category: 5 Medium: Water 2008 Category: 5 Parameter: Dissolved Oxygen 2004 Category: 5 WQI Project: None Assigned On 1998 303(d) List?: Y Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 17110013002282 Location Identification Counties: King Waterbody ID (WBID): None Assigned Town/Range/Section (Legacy): 21N-4E-1 WRIA: 9 - Duwamish-Green Waterbody Class: RA Basis Location ID: [KCM-A315] -- In 2008, 8 of 12 sample values (67%) showed an excursion of the criterion (8 mg/L) for this waterbody; Location ID: [KCM-A315] -- In 2007, 10 of 12 sample values (83%) showed an excursion of the criterion (8 mg/L) for this waterbody; Location IDs: [KCM-A315], [09-MIL-WAS] -- In 2006, 11 of 15 sample values (73%) showed an excursion of the criterion (8 mg/L) for this waterbody; Location ID: [KCM-A315] -- In 2005, 11 of 14 sample values (79%) showed an excursion of the criterion (8 mg/L) for this waterbody; Location ID: [KCM-A315] -- In 2004, 11 of 13 sample values (85%) showed an excursion of the criterion (8 mg/L) for this waterbody; King County unpublished data from station A315 (Hill Creek RM 0.3) show excursions beyond the dissolved oxygen criterion in 1998, 1999, 2000, 2001 and 2002. King County, 1993, 10 excursions out of 10 samples (100%) beyond the criterion at station 302 (RM 1.0) during 1992 and 1993. King County, 1993, 9 excursions out of 10 samples (90%) beyond the criterion at station 303 (RM 1.4) during 1992 and 1993. King County, 1993, 3 excursions out of 7 samples (43%) beyond the criterion at station 304 (RM 2.2) during 1992 and 1993. King County, 1993, 1 excursions out of 10 samples (10%) beyond the criterion at station 305 (RM 7.5) during 1992 and 1993. Remarks Remark Modified By Modified On Visibility Combined Listing: Listing IDs 15814, 15811, 15810, 12707, 47539 were rolled into this listing Chad Brown 9/24/2015 Public 10/3/2014 Public Page 1 of 2Print Approved Listing 1/17/2019https://fortress.wa.gov/ecy/approvedwqa/ApprovedPrintListing.aspx?LISTING_ID=7488 141 318 of 628 Ten percent or more of the samples collected in a single year were excursions of the criterion, and at least 3 excursions exist from all data considered. Jessica Archer EIM User Study ID:User Location ID: KCstrm-1 KCM-A315 KCstrm-1 KCM-A315 MROB003 09-MIL-WAS Print Page 2 of 2Print Approved Listing 1/17/2019https://fortress.wa.gov/ecy/approvedwqa/ApprovedPrintListing.aspx?LISTING_ID=7488 142 319 of 628 Listing ID: 12645 Main Listing Information Listing ID: 12645 2014 Category: 5 Waterbody Name: MILL CREEK 2012 Category: 2 Medium: Water 2008 Category: 2 Parameter: pH 2004 Category: 2 WQI Project: None Assigned On 1998 303(d) List?: N Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 17110013002282 Location Identification Counties: King Waterbody ID (WBID): None Assigned Town/Range/Section (Legacy): 22N-4E-25 WRIA: 9 - Duwamish-Green Waterbody Class: RA Basis Location ID [KCM-A315] -- In 2008, 0 of 15 sample values (0%) showed an excursion of the criteria for this waterbody; Location ID [KCM-A315] -- In 2007, 1 of 12 sample values (8%) showed an excursion of the criteria for this waterbody; Location ID [KCM-A315], [09-MIL-WAS] -- In 2006, 0 of 15 sample values (0%) showed an excursion of the criteria for this waterbody; Location ID [KCM-A315] -- In 2005, 0 of 14 sample values (0%) showed an excursion of the criteria for this waterbody; Location ID [KCM-A315] -- In 2004, 2 of 13 sample values (15%) showed an excursion of the criteria for this waterbody; Location ID [Data from multiple locations] -- In 2006, 0 of 12 samples (0.0%) showed an excursion of the criteria for this waterbody. King County unpublished data from station A315 show 3 excursions beyond the criteria out of 73 all samples collected between 1998 and 2002. Remarks Remark Modified By Modified On Visibility Combined Listing: Listing ID 50827 was rolled into this listing Chad Brown 9/24/2015 Public Low pH Excursions Jessica Archer 7/23/2014 Public At least 10 percent of samples were excursion of the criteria in at least one year and at least 3 excursions exist from all data considered. Jessica Archer 7/23/2014 Public EIM User Study ID:User Location ID: KCstrm-1 KCM-A315 Page 1 of 2Print Approved Listing 1/17/2019https://fortress.wa.gov/ecy/approvedwqa/ApprovedPrintListing.aspx?LISTING_ID=12645 143 320 of 628 MROB003 09-MIL-WAS Print Page 2 of 2Print Approved Listing 1/17/2019https://fortress.wa.gov/ecy/approvedwqa/ApprovedPrintListing.aspx?LISTING_ID=12645 144 321 of 628 145 Attachment D Special Reports 322 of 628 146 Attachment D-1 Geotechnical Report 323 of 628 October 2, 2018 Revised January 14, 2019 Stowe Construction PO Box 1054 Sumner, Washington 98390 Attn: Mr. Bryan Stowe stowerock@aol.com Revised Preliminary Geotechnical Engineering Report Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, -0320 & 0313 Doc ID: StoweConst.56thAveS.RGu.Rev01 INTRODUCTION This revised prel iminary geotechnical engineering report summarizes our site observations, subsurface explorations, laboratory testing and engineering analyses and provides geotechnical recommendations and design criteria for the proposed residential development to be constructed at 32727 – 56th Avenue South in Auburn, Washington. The site location is shown on the Site Location Map, Figure 1. We previously prepared a draft Geotechnical Engineering Report for two of the above- mentioned parcels (PN: 9262800295, & -0320) dated June 16, 2017. We understand that you are adding an additional parcel (PN: 9262800313) to the development; therefore, City of Auburn is requiring a Geotechnical Engineering Report be prepared to satisfy City of Auburn Critical Areas Ordinances, and Development Codes. Changes to the original report text are presented in bold and italicized text. Our understanding of the project is based on our correspondence with Mr. Bryan Stowe of Stowe Construction, our review of the conceptual Site Plan prepared by Barghausen Consulting Engineering, Inc. dated January 27, 2017, our review of the Preliminary Road and Drainage Plan prepared by Barghausen Consulting Engineering, Inc. dated January 11, 2019, our previous May 16, 2007 site visit and subsurface explorations, our recent September 25, 2018 site visit and subsurface explorations, our understanding of the City of Auburn Critical Areas Ordinances, and Development Codes, our understanding of the 2012 Department of Ecology Stormwater Management Manual for Western Washington (SWMMWW), with the 2014 amendments, and our experience in the area. The site consist of a three tax parcels located west of the intersection of 56th Avenue South and South 328th Street. The northern parcel (PN: 9262800295) and the southern parcels (PN: 9262800320 & 9262800313) are separated by the South 328th Street Right-Of-Way. The northern parcel is developed with a shop. We understand that you propose to construct 44 single family residences, several paved access tracts, and associated utilities on the above mentioned parcels. We further understand that you propose to construct a drainage facility at Tract A, in the southern portion 147 324 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 2 of the site. We anticipate that the new residences will be a one or two-story, wood-framed structures likely founded on conventional shallow foundations. We anticipate the residences on lots 30 through 43 will likely have a daylight basement configuration, while the residences on the other lots will likely have a crawl space under the living area and slab-on-grade floors under the garages. SCOPE The purpose of our services is to evaluate the surface and subsurface conditions at the site as a basis for addressing City of Auburn requirements as well as addressing the potential of the site soils for supporting foundation loads. We have also included geotechnical recommendations for the project. Specifically, the scope of services for this project will include the following: 1. Reviewing existing geological, hydrogeological, and geotechnical literature for the site area; 2. Exploring the subsurface conditions by performing a geotechnical reconnaissance; 3. Exploration subsurface conditions across the site by excavating 6 additional test pits in the additional parcel at select locations; 4. Collect select soil samples from the explorations and conduct 3 grain size analyses; 5. Describing surface and subsurface conditions, including soil type, depth to groundwater, and estimate of high groundwater; 6. Addressing the appropriate criteria for Geologic Hazards per the current City of Auburn Critical Areas Ordinance; 7. Providing geotechnical conclusions and recommendations regarding seismic site class and design coefficients, seismic hazard analysis, site grading activities including; site preparation, subgrade preparation, fill placement criteria, suitability of on-site soils for use as structural fill, temporary and permanent cut and fill slopes, drainage and erosion control measures; 8. Providing conclusions regarding foundations, including shallow conventional footings, along with floor slab support and design criteria, including bearing capacity and subgrade modulus if appropriate; 9. Providing our opinion about the feasibility of onsite infiltration in accordance with the 2012 SWMMWW, including a preliminary design infiltration rate based on grain size data, as appropriate, to meet the Soils Report requirement of the 2012 SWMMWW; 10. Performing 2 small scale Pilot Infiltration Test (PIT) in accordance with the 2012 SWMMWW, Volume III, Section 3.3.6, if infiltration appeared to be feasible; 11. Providing recommendations for erosion and sediment control during wet weather grading and construction; and 12. Preparing a written Geotechnical Engineering Report with design recommendations summarizing our site observations and conclusions, and our geotechnical recommendations and design criteria, along with the supporting data. The above scope of work was summarized in our Proposal for Geotechnical Engineering Services dated September 21, 2018. We received authorization to proceed from you on September 25, 2018. 148 325 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 3 SITE CONDITIONS Surface Conditions The site is located at 32727 – 56th Avenue South, Auburn, Washington, within an area of existing residential development in the Auburn uplands. According to the information obtained from the King County iMap website, the site encompasses three tax parcels east of the intersection of 56th Avenue South and South 328th Street. The northern parcel (PN: 9262800295) is generally rectangular in shape, the southeastern parcel (PN: 9262800320) is a L-shaped parcel, and the southwestern parcel (PN: 9262800313) is a mirrored C-shaped parcel. Each parcel measures approximately 300 feet wide (north to south) by approximately 620 feet deep (east to west). The three tax parcels, when combined, encompass approximately 10.23 acres. The site is bounded by 56th Avenue South to the east, by 51st Avenue South to the west, by an undeveloped parcel and existing residential development to the north, and by existing residential development to the south. The northern parcel is currently developed with a shop, while the southern parcels are undeveloped. The northern parcel and the southern parcels are separated by the South 328th Street Right-Of-Way. According to the information obtained from the King County iMap website, the northern parcel generally slopes down from 56th Avenue South to the west at approximately 8 to 15 percent. The upper portion of the northern parcel is generally flat before the parcel slopes down to the west at about 8 to 15 percent. The lower portion of the northern parcel consists of a gently slope drainage that slopes down to the south. The drainage continues onto the southeastern parcel and slopes down to the south at approximately 5 to 10 percent. The southeastern parcel slopes up to the northeast towards 56th Avenue South at about 15 to 20 percent. The southwestern parcel generally slopes down to the south and the west. The upper portion of the southwestern parcel generally slopes down to the south at approximately 8 to 15 percent. The western portion of this parcel generally slopes down to the west at approximately 12 to 18 percent. The total topographic relief across the site is on the order of 50 to 55 feet. The existing site configuration and conditions are shown on the attached Site Vicinity Map, included as Figure 2a. Vegetation in the undeveloped portions of the site generally consist of a moderate stand of a mixture of deciduous and coniferous trees with a moderate understory of native and invasive plants and shrubs. Vegetation in the drainage channel areas generally consist of a moderate stand understory of native and invasive plants and shrubs. No evidence of standing water, seeps, or springs was observed at the site at the time of our site visit. Site Soils The National Resource Conservation Service (NRCS) Web Soil Survey maps the site as being underlain by Alderwood gravelly sandy loam (AgC) soils. The Alderwood soils are derived from glacial till, form on slopes of 8 to 15 percent, are listed as having a “moderate” erosion hazard when exposed, and are included in hydrologic soils group B. A copy of the NRCS soils map for the site vicinity is attached as Figure 3. Site Geology The Geologic Map of the Poverty Bay 7.5-minute Quadrangle, Washington by Derek B. Booth, Howard H. Waldron, and Kathy G. Troost (2003) maps the site as being underlain by glacial till (Qvt). These glacial soils were deposited during the most recent Vashon Stade of the Fraser Glaciation, 12,000 to 15,000 years ago. The glacial till consists of a heterogeneous mixture of gravel, sand, silt, and clay that was deposited at the base of the continental ice mass and subsequently overridden. As 149 326 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 4 such, this geologic unit is considered over-consolidated and provides high strength, low compressibility and low porosity and permeability characteristics where undisturbed. No landslides or landslide deposits are mapped within 300 feet of the site. No evidence of soil movement was reported or observed at the site at the time of our site visit. No areas of landslides or mass wasting are mapped at or near the site. An excerpt of the referenced geologic map is included as Figure 4. Subsurface Explorations On May 16, 2017, a field representative from GeoResources, LLC (GeoResources) visited the site and monitored the excavation of 7 test pits to depths of about 3 to 10½ feet below the existing ground surface as part of the draft Geotechnical Engineering Report, dated June 16, 2017. On September 25, 2018, a field representative from GeoResources returned to the site and monitored the excavation of 6 additional test pits to depths of about 4½ to 5½ feet below the existing ground surface, logged the subsurface conditions encountered in each test pit, and obtained representative soil samples. The test pits were excavated by a medium track-mounted excavator operated by you. The specific number, locations, and depths of our explorations were selected based on the configuration of the proposed development and were adjusted in the field based on consideration for underground utilities, existing site conditions, site access limitations and encountered stratigraphy. Representative soil samples obtained from the test pits were placed in sealed plastic bags and then taken to a laboratory for further examination and testing as deemed necessary. The test pits were then backfilled with the excavated soils and bucket tamped, but not otherwise compacted. Table 1, below, summarizes the approximate functional locations, surface elevations, and termination depths of our subsurface explorations. TABLE 1: APPROXIMATE LOCATIONS, ELEVATIONS, AND DEPTHS OF EXPLORATIONS Test Pit Number Functional Location Surface Elevation1 (feet) Termination Depth (feet) Termination Elevation1 (feet) TP-1 TP-2 TP-3 TP-4 TP-5 TP-6 TP-7 N-central portion of parcel 9262800295 NW corner of parcel 9262800295 SW corner of parcel 9262800295 S-central portion of parcel 9262800320 Central portion of parcel 9262800320 N-central portion of parcel 9262800320 NE corner of parcel 9262800295 414 415 414 402 415 408 427 3 9 4½ 8¾ 10½ 8 5 411 406 409½ 393¼ 404½ 400 422 TP-101 TP-102 TP-103 TP-104 TP-105 TP-106 NE corner of parcel 9262800295 NW corner of parcel 9262800313 S-central portion of parcel 9262800313 N-central portion of parcel 9262800313 NE corner of parcel 9262800313 SE corner of parcel 9262800313 431 420 419 424 414 414 5 5 4½ 5½ 5½ 5½ 426 415 414½ 418½ 408½ 408½ Notes: 1 = Elevation datum based on King County iMap website 150 327 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 5 The subsurface explorations excavated as part of this evaluation indicate the subsurface conditions at specific locations only, as actual subsurface conditions can vary across the site. Furthermore, the nature and extent of such variation would not become evident until additional explorations are performed or until construction activities have begun. Based on our experience in the area and extent of prior explorations in the area, it is our opinion that the soils encountered in the explorations are generally representative of the soils at the site. The soils encountered were visually classified in accordance with the Unified Soil Classification System (USCS) and ASTM D: 2488. The USCS is included in Appendix A as Figure A-1. The approximate locations of our test pits are indicated on the attached Site and Exploration Plan, Figure 2 b, while the descriptive logs of our test pits are included in Appendix A as Figures A-2 through A-4. Subsurface Conditions The subsurface conditions encountered in our 2017 explorations were fairly uniform across the site, and generally confirmed the mapped stratigraphy. In general, our test pits encountered about 1 to 8½ feet of dark brown to grey brown topsoil/fill with organics and construction debris. Underlying the surficial soils in test pits TP-1, TP-3, and TP-4, we encountered brown to grey with iron oxide staining/mottling silty sand and gravel in very dense, damp condition that was encountered to the full depth explored. We interpret these soils to be glacial till. Underlying the surficial soils in test pits TP-2, TP-5, and TP-6, we encountered about ½ to 4½ feet of brown to grey with iron oxide staining/mottling sandy silt in a medium dense, damp condition. These soils were encountered to the full depth explored in test pit TP-5. Underlying the silt, we encountered brown to grey silty sand with gravel in a very dense, damp to saturated condition. We interpret these soils to be glacial till. In test pit TP-7, we encountered about 2½ feet of brown silty sand and gravel in a very dense, moist condition mantling grey silty sand with gravel in a dense, moist condition. We interpret these soils to be weathered till over glacial till. Previous subsurface exploration logs and corresponding laboratory test results are included in Appendix C. Our recent test pits encountered fairly uniform subsurface conditions that generally confirmed our previous subsurface explorations and the mapped stratigraphy. In general, our test pits encountered approximately ½ to 1 foot of dark brown topsoil. Underlying the topsoil, test pit TP-101 encountered approximately 1½ feet of brown silty sand with gravel and some to trace organics in a medium dense, moist condition. We interpret these soils to be previously placed, undocumented fill material. Underlying the fill, we encountered approximately 1 foot of dark brown relict topsoil with abundant organics in a loose, saturated condition. The saturated condition is likely the result of the infiltration testing. Underlying the relict topsoil, we encountered approximately 1 foot of reddish brown with iron oxide staining/mottling silty sand with gravel in a loose to medium dense, moist condition mantling brown grey silty sand with gravel in a dense, moist condition that was encountered to the full depth explored. We interpret these deeper soils to be weathered till over glacial till. Underlying the topsoil in test pits TP-103, TP-104, TP-105 and TP-106, we generally encountered approximately 1 to 2 feet of brown with iron oxide staining/mottling silty sand with varying amounts of gravel and occasional boulders in a medium dense, moist condition mantling grey silty sand with varying amounts of gravel in a dense, moist condition that was encountered to the full depth explored. We interpret these soils to be weathered till over glacial till. Underlying the topsoil in test pit TP-102, we encountered approximately 2 feet of brown grey with some iron oxide staining/mottling gravel with silt and sand in a loose to medium dense, moist condition mantling grey silty gravel with sand in a dense, 151 328 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 6 saturated becomes moist condition that was encountered to the full depth explored. These soils were observed to become less wet at approximately 3½ feet below the existing ground surface. We interpret these soils to be gravelly weathered till over glacial till. The saturated condition is likely the result of the infiltration testing. Table 2, below, summarizes the approximate thicknesses, depths, and elevations of selected soil layers encountered in our previous and recent subsurface explorations. TABLE 2: APPROXIMATE THICKNESS, DEPTHS, AND ELEVATION OF SOIL TYPES ENCOUNTERED IN EXPLORATIONS Test Pit Number Thickness of Topsoil/Fill (feet) Depth to Top of Silt (feet) Depth to Top of Weathered/Glacial Till (feet) Elevation1 to Top of Weathered/Glacial till (feet) TP-1 TP-2 TP-3 TP-4 TP-5 TP-6 TP-7 2 2½ 2½ 8½ 10 6 1 NE 2½ NE NE 10 6 NE 2 7 2.5 8.5 NE 6.5 3.5 412 408 411½ 393½ NE 401½ 423½ TP-101 TP-102 TP-103 TP-104 TP-105 TP-106 3 ¾ 1 1 1 1 NE NE NE NE NE NE 3 ¾ 1 1 1 1 428 419¼ 418 423 413 413 Notes: 1 = Elevation datum based on King County iMap website NE = Not encountered within depth explored Laboratory Testing Geotechnical laboratory tests were performed on select samples retrieved from the test pits to determine soil index and engineering properties encountered. Laboratory testing included visual soil classification per ASTM D: 2488, grain size analyses per ASTM D: 422, modified proctor per ASTM D:1557, and California bearing ratio (CBR) test per ASTM D:1883 standard procedures. The CBR test, and the corresponding grain size analysis and modified proctor were performed by an independent analytical laboratory. The results of the laboratory tests are included in Appendix B, and summarized below in Table 3. 152 329 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 7 TABLE 3: LABORATORY TEST RESULTS FOR ON-SITE SOILS Soil Type Sample Lab ID Numbe r Gravel Content (percent) Sand Content (percent) Silt/Clay Content (percent) CBR (percent) Glacial Till Glacial Till TP-3, S-2, 4¼’ TP-7, S-1, 2½’ 092686 092687 64.3 55.1 28.3 35.7 7.4 9.2 NT NT Glacial Till Weathered Till Glacial Till Weathered Till TP-102, S-1, 2’ TP-106, S-1, 1-3’ TP-106, S-2, 3-5.5’ TP-106, S-1, 1’ 095623 095633 095634 18L447 63.0 55.9 39.0 25.4 29.9 31.7 36.8 54.1 7.1 12.4 14.2 20.5 NT NT NT 17.7 NT = Not tested Cat-ion exchange capacity (CEC) and organic content testing were also performed by an independent laboratory to evaluate the treatment capacity of the shallow onsite soils for LID methods. The results of the laboratory tests are included in Appendix B. The shallow onsite soils contain a cation exchange capacity (CEC) of 4.8 to 6.5 milliequivalents (meq)/100g per SW846 9081 and an organic content of 2.5 to 2.8 percent per ASTM D 2974-13. Groundwater Conditions No groundwater seepage was observed in our recent test pits at the time of excavation. However, groundwater seepage was observed in our test pits TP-1, TP-2, TP-3, and TP-4 at approximately 2 to 8½ feet below the existing ground surface at the time of excavation in 2017. Mottling was observed in some of our previous test pits at approximately 2½ to 6 feet below the existing ground surface, and mottling was observed in all our recent test pits at approximately 1 to 3 feet below the existing ground surface. Groundwater levels within the Auburn Valley are commonly very shallow, on the order of 5 to 10 feet below the ground surface. Mottling may be indicative of seasonal or fluctuating groundwater surface, often associated with a seasonal perched groundwater table. Perched groundwater develops when the vertical infiltration of precipitation through a more permeable soil, such as weathered till, is slowed at depth by a deeper, less permeable soil type, such as glacial till. We expect that perched groundwater may develop seasonally atop the medium dense to dense till soils in the site area. We anticipate fluctuations in the local groundwater levels will occur in response to precipitation patterns, off-site construction activities, and site utilization. Table 4, below, summarizes our depth to and elevation of groundwater encountered in our test pits. 153 330 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 8 TABLE 4: APPROXIMATE DEPTHS AND ELEVATIONS OF GROUNDWATER ENCOUNTERED IN EXPLORATIONS Exploration Number Depth to Groundwater (feet) Elevation of Groundwater (feet) Date Observed TP-1 2 412 May 16, 2017 (ATE) TP-2 2 413 May 16, 2017 (ATE) TP-3 2½ 411½ May 16, 2017 (ATE) TP-4 8½ 393½ May 16, 2017 (ATE) 1 = Elevation datum based on King County iMap website ATE = At the time of exploration Infiltration Testing On September 25, 2018, a field representative from GeoResources performed two small scale pilot infiltration testing (PIT) PIT-1 and PIT-2 in the eastern portion of the site and western portion of the site, respectively, in general accordance with the 2012 Department of Ecology Stormwater Management Manual for Western Washington (SWMMWW), Volume III, Section 3.3.6. As stated, we were provided with the conceptual Site Plan prepared by Barghausen Consulting Engineering, Inc. dated January 27, 2017. However, we have not been provided with any Civil/Stormwater Plans at the time of preparing this report or prior to completing the PITs. The specific number, location, and depth of our PITs were adjusted in the field based on consideration for underground utilities, existing site conditions, site access limitations, water access limitations and encountered stratigraphy. The approximate location of the infiltration testing pits are shown on the attached Site and Exploration Plan, Figure 2 b. The infiltration testing pits were excavated by a small track-mounted excavator operated by you. PIT-1 was performed at approximately 1 foot below the existing ground surface in the brown silty sand with gravel in a medium dense, moist condition. PIT- 2 was performed at approximately 2 feet below the existing ground surface in the brown grey gravel with silt and sand in a loose to medium dense, moist condition. The bottom of both infiltration tests PIT-1 and PIT-2 measured approximately 3 feet wide by approximately 4½ feet long. We measured a short term infiltration rate of approximately 1.1 and 15 inches per hour for PIT-1 and PIT-2, respectively. The infiltration pits were overexcavated following the completion of the small infiltration testing. Underlying the infiltration test PIT-1, we encountered approximately 1 foot of the similar silty sand with gravel soils that was generally observed at the bottom of the testing in PIT-1. Underlying the silty sand with gravel soils, we encountered approximately 1 foot of dark brown relict topsoil in a saturated condition. We interpret the upper silty sand with gravel soils to be previously placed, undocumented fill material. Underlying the relict topsoil, we encountered weathered till over glacial till in a medium dense to dense, moist condition that was encountered to the full depth explored. The moist conditions observed in the weathered till and glacial till soils, indicates the water in the infiltration test did not infiltrate into the weathered till and glacial till soils. As stated, we measured a short term infiltration rate of approximately 1.1 inches per hour for PIT-1. However, this measured short term infiltration rate should not be considered or used for any design criteria of 154 331 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 9 stormwater management facilities because of the presence of undocumented fill material and less permeable layers during the over-excavation at the end of infiltration testing. Underlying the infiltration pit PIT-2, we encountered approximately ½ foot of the similar brown grey gravel with silt and sand in a loose to medium dense, saturated condition mantling grey silty gravel with sand in a dense, saturated condition. These soils become moist condition at approximately 3½ feet below the existing ground surface (approximately 1½ feet below the bottom of the testing in PIT-2) that was encountered to the full depth explored. We measured a short term infiltration rate of approximately 15 inches per hour for PIT-2. The dense nature and the moist condition of the underlying soils, indicates the water in the infiltration pit did not infiltrate into the underlying soils. Therefore, this measured short term infiltration rate should not be considered or used for any design criteria of stormwater management facilities because of the presence of less permeable layers during the over-excavation at the end of infiltration testing. It should be noted that these measured short term infiltration rates only represent the brown silty sand with gravel soils and the brown grey gravel with silt and sand soils in PIT-1 and PIT- 2, respectively, and that specific infiltration rates could not be provided for other portions of the site, because of site access and water access restrictions. Recommendations regarding the stormwater infiltration are discussed and included in the “Stormwater Infiltration” section below. CONCLUSIONS AND RECOMMENDATIONS Based on the results of our data review, site reconnaissance, subsurface exploration program, and the presence of groundwater, without mitigation, a spread footing support directly above the existing soils could result in adverse differential settlement. In order to reduce the potential for adverse post-construction settlement, we therefore recommend that the proposed buildings be supported by conventional spread footings on compacted native soils. The foundation should provide the necessary long-term support for the structure, provided it is properly designed and installed. Pertinent conclusions and geotechnical recommendations regarding the design and construction of the proposed development are presented below. Critical Areas Based on the results of our site reconnaissance, subsurface explorations, and our experience in the area, it is our opinion that the site does not meet the technical criteria of a geologic hazard area. Provided the design criteria listed below are followed, the proposed structure will have no greater seismic risk damage than other appropriately designed structures in the Puget Sound area. Liquefaction Potential The presence of dense granular sand and gravel conditions were assumed to be representative for the site conditions beyond the depths explored. Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength due to an increase in pore water pressure in soils. The increase in pore water pressure is induced by seismic vibrations. Liquefaction mainly affects geologically recent deposits of loose, uniformly graded, fine-grained sands that are below the groundwater table. In our opinion, the soils encountered in the test pits consist of medium dense to dense sands and gravels with varying amounts of silt beneath the groundwater table. In our opinion, the risk of liquefaction-induced settlements in these soils during a seismic 155 332 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 10 event are low. Provided the design criteria listed below are followed, the proposed structure will have no greater seismic risk damage than other appropriately designed structures in the Puget Sound area. Seismic Site Class Based on our observations and the subsurface units mapped at the site, we interpret the structural site conditions to correspond to a seismic Site Class “D” for the onsite soils in accordance with the 2015 IBC (International Building Code) documents and ASCE 7-10 Chapter 20 Table 20.3-1. For design of seismic structures using the IBC 2015, mapped short-period and 1-second period spectral accelerations, SS and S1, respectively, are required. The U.S. Geological Survey (USGS) completed probabilistic seismic hazard analyses (PSHA) for the entire country in November 1996, which were updated and republished in 2002 and 2008. The PSHA ground motion results can be obtained from the USGS website. The results of the updated USGS PSHA were referenced to determine SS and S1 for this site. The results are summarized in the following table with the relevant parameters necessary for IBC 2015 design. TABLE 5: 2015 IBC PARAMETERS FOR DESIGN OF SEISMIC STRUCTURES Spectral Response Acceleration (SRA) and Site Coefficients Short Period 1 Second Period Mapped SRA Ss = 1.276 S1 = 0.488 Site Coefficients (Site Class D) Fa = 1.0 Fv = 1.512 Maximum Considered Earthquake SRA SMS = 1.276 SM1 = 0.738 Design SRA SDS = 0.850 SD1 = 0.492 Foundation Support Based on the subsurface soil conditions encountered across the site, and the conceptual Site Plan prepared by Barghausen Consulting Engineering, Inc. dated January 27, 2017, we recommend that the structures be supported by conventional spread and column footings. All footings should be founded on the medium dense to dense weathered till or glacial till soils, or on structural fill that extends to suitable native soils. We do not recommend footings be founded on the previously placed, undocumented fill or the shallow loose, weathered soils. The native soils at the base of the excavations should be disturbed as little as possible and should be mechanically compacted to a dense and unyielding condition that should provide adequate support for shallow spread footings. All loose, soft or unsuitable material should be removed or recompacted, as appropriate. If material is over excavated below a footing, it should be replaced with controlled density fill (CDF), structural concrete or suitable structural fill. A rat slab of CDF or clean crushed rock could be placed after excavation to prevent disturbance of the subgrade. A geotechnical expert or representative of GeoResources LLC should observe the foundation subgrade at the time of excavation to determine if suitable bearing surfaces have been prepared. 156 333 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 11 We recommend a minimum width of 24 inches for isolated footings and at least 18 inches for continuous wall footings. All footing elements should be embedded at least 18 inches below grade for frost protection. Footings founded on the native, compacted weathered till soils or on suitable structural fill that extends down to the suitable native soils can be designed using an allowable soil bearing capacity of 2,500 psf (pounds per square foot) for combined dead and long- term live loads. Footings founded on the deeper, native glacial till soils can be designed using an allowable soil bearing capacity of 3,500 psf for combined dead and long-term live loads. The allowable bearing value may be increased by one-third for transient loads such as those induced by seismic events or wind loads. Lateral loads may be resisted by friction on the base of footings and floor slabs and as passive pressure on the sides of footings. We recommend that an allowable coefficient of friction of 0.35 be used to calculate friction between the concrete and the underlying soil. Passive pressure may be determined using an allowable equivalent fluid density of 350 pcf (pounds per cubic foot). Factors of safety have been applied to these values. We estimate that settlements of footings designed and constructed as recommended will be less than 1-inch, for the anticipated load conditions, with differential settlements between comparably loaded footings of ½-inch or less across a 50–foot span. Most of the settlements should occur essentially as loads are being applied. However, disturbance of the foundation subgrade during construction could result in larger settlements than predicted. We have not been provided with the actual loads to determine what the actual total and differential settlements could be. Floor Slab Support We anticipate that the residences will have slab-on-grade floors under the garage. Slab-on- grade floors, if constructed, should be supported on the native medium dense weathered till soils or on structural fill prepared as described above. Areas of old fill material should be evaluated during grading activity for suitability of structural support. Areas of significant organic debris, fines, or other debris should be removed and replaced with appropriately prepared structural fill. We recommend that floor slabs be directly underlain by a capillary break of a minimum 4- inch thick pea gravel or clean 5/8-inch crushed rock. This layer should be placed and compacted to an unyielding condition and should contain less than 2 percent fines. A synthetic vapor retarder is recommended to control moisture migration through the slabs. This is of particular importance where the foundation elements are underlain by the silty till or lake sediments, or where moisture migration through the slab is an issue, such as where adhesives are used to anchor carpet or tile to the slab. A subgrade modulus of 350 kcf (kips per cubic foot) may be used for floor slab design. We estimate that settlement of the floor slabs designed and constructed as recommended, will be ½- inch or less over a span of 50 feet. Subgrade and Below Grade Walls The lateral pressures acting on subgrade and retaining walls (such as basement walls) will depend upon the nature and density of the soil behind the wall. It is also dependent upon the presence or absence of hydrostatic pressure. If the walls are backfilled with granular well-drained soil, the design active pressure may be taken as 35 pcf (equivalent fluid density). Where the walls are restrained from lateral deformation, we recommend an at-rest equivalent earth pressure of 55 pcf. These design values assume a level backslope and drained conditions as described below. Where 157 334 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 12 required by code, a seismic surcharge of 10H is recommended for active conditions, calculated using the Mononobe-Okabe method. This surcharge is in addition to the static lateral earth pressure and should be assumed to have resultant at 2/3H, and assumes the wall will be backfilled with adequately compacted structural fill. Adequate drainage behind retaining structures is imperative. Positive drainage which controls the development of hydrostatic pressure can be accomplished by placing a zone of drainage behind the walls. Granular drainage material should contain less than 2 percent fines and at least 30% greater than the No. 4 sieve. A geocomposite drain mat may also be used instead of free draining soils, provided it is installed in accordance with the manufacturer’s instructions. A soil drainage zone should extend horizontally at least 18 inches from the back of the wall. The drainage zone should also extend from the base of the wall to within 1 foot of the top of the wall. The soil drainage zone should be compacted to approximately 90 percent of the MDD (maximum dry density as determined in accordance with ASTM D-1557). Over-compaction should be avoided as this can lead to excessive lateral pressures. A minimum 4-inch diameter perforated, or slotted PVC pipe should be placed in the drainage zone along the base and behind the wall to provide an outlet for accumulated water and direct accumulated water to an appropriate discharge location. We recommend that a nonwoven geotextile filter fabric be placed between the soil drainage material and the remaining wall backfill to reduce silt migration into the drainage zone. The migration of silt into the drainage zone can, with time, reduce the permeability of the granular material. The filter fabric should be placed such that it fully separates the drainage material and the backfill and should be extended over the top of the drainage zone. Lateral loads may be resisted by friction on the base of footings and as passive pressure on the sides of footings and the buried portion of the wall, as described in the “Foundation Support” section. We recommend that an allowable coefficient of friction of 0.35 be used to calculate friction between the concrete and the underlying soil. Passive pressure may be determined using an allowable equivalent fluid density of 350 pcf (pounds per cubic foot). Factors of safety have been applied to these values. Temporary Excavations All job site safety issues and precautions are the responsibility of the contractor. The following cut/fill slope guidelines are provided for planning purposes only. Temporary cut slopes will likely be necessary during grading operations or utility installation. All excavations at the site associated with confined spaces, such as utility trenches and retaining walls, must be completed in accordance with local, state, or federal requirements. Based on current Washington Industrial Safety and Health Act (WISHA) regulations, the fill and the weathered soils encountered on the site would be classified as Type C soils, and the deeper glacial till would be classified as Type A soils. According to WSHA, for temporary excavations of less than 20 feet in depth, the side slopes in Type C soils should be sloped at a maximum inclination of 1½H:1V, and the side slopes in lower Type A soils should be sloped at a maximum inclination of 0.75H:1V. All exposed slope faces should be covered with a durable reinforced plastic membrane during construction to prevent slope raveling and rutting during periods of precipitation. These guidelines assume that all surface loads are kept at a minimum distance of at least one half the depth of the cut away from the top of the slope and that significant seepage is not present on the slope face. Flatter cut slopes will be 158 335 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 13 necessary where significant raveling or seepage occurs, or if construction materials will be stockpiled along the slope crest. As stated in our preliminary Geotechnical Report, dated January 28, 2007, we recommend the temporary cut slopes be sloped at no steeper than inclination of 2H:1V along the northern and southern property boundaries. Where it is not feasible to slope the site soils back at these inclinations, a retaining structure should be considered. Where retaining structures are greater than 4-feet in height (bottom of footing to top of structure) or have slopes of greater than 15 percent above them, they should be engineered per Washington Administrative Code. This information is provided solely for the benefit of the owner and other design consultants and should not be construed to imply that GeoResources assumes responsibility for job site safety. It is understood that job site safety is the sole responsibility of the project contractor. Site Drainage All ground surfaces, pavements and sidewalks at the site should be sloped away from the structures. The site should also be carefully graded to ensure positive drainage away from all structures and property lines. Surface water runoff should be controlled by a system of curbs, berms, drainage swales, and or catch basins, and conveyed to an appropriate discharge point. We recommend that footing drains are installed for the residence in accordance with IBC 1805.4.2, and basement walls (if utilized) have a wall drain as described above. The roof drain should not be connected to the footing drain. Figure 5 shows typical wall drainage and backfilling details. If the basement cut extends below the adjacent municipal stormwater system, a sump and pump system may be required. Permanent Cut and Fill Slopes We recommend a maximum slope of 2H:1V (Horizontal:Vertical) for all permanent cut and fill slopes. Based on our review of the Preliminary Road and Drainage Plan prepared by Barghausen Consulting Engineering, Inc. dated January 11, 2019, we anticipate permanent cut and fill slopes will be utilized in the southern portion of the site. Proposed cuts in the lots to allow construction of daylight basements will be 2H:1V, whi le slopes along the back of lots 25 through 41, in the pond area, will be 3H:1V. Where 2H:1V slopes are not feasible, retaining structures should be considered. Where retaining structures are greater than 4 feet in height (bottom of footing to top of structure) or have slopes above them, they should be designed by a qualified engineer. Fill placed on slopes that are steeper than 5H:1V (20 percent) should be "keyed" into the undisturbed native soils by cutting a series of horizontal benches, and should be constructed in accordance with Appendix J of the 2015 IBC. An excerpt from the 2015 IBC, Appendix J is included as Figure 6. The benches should be 1½ times the width of the equipment used for grading and be a maximum of 3 feet in height. Subsurface drainage may be required in areas where significant seepage is encountered during grading. Collected drainage should be directed to an appropriate discharge point. Surface drainage should be directed away from all slope faces. All slopes should be protected from erosion. Additionally, permanent slopes should be seeded and planted with a mulch, hardy vegetative groundcover or armored with quarry spalls as soon as feasible after grading is completed. 159 336 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 14 Stormwater Infiltration The soils encountered in our subsurface explorations varied slightly across the site. As stated, mottling was observed in some of our previous test pits at approximately 2½ to 6 feet below the existing ground surface, and mottling, an indicator of seasonal high perched groundwater table was observed in all our recent test pits at approximately 1 to 3 feet below the existing ground surface. Groundwater seepage was also observed in four of our previous test pits at approximately 2 to 8½ feet below the existing ground surface at the time of excavation. Some previously placed, undocumented fill was also observed below the existing ground surface in portions of the project site. We performed two small scale pilot infiltration testing PIT-1 and PIT-2 in general accordance with the 2012 Department of Ecology Stormwater Management Manual for Western Washington (SWMMWW), Volume III, Section 3.3.6. Indicators of impermeable layers underlying the infiltration pits were observed when we over-excavated the test location following completion of the infiltration testing, as required. Per the 2012 Stormwater Management Manual for Western Washington (SWMMWW), with the 2014 amendments, Volume III, Section 3.3.7, a minimum of 1 foot of separation is required between the bottom of a proposed infiltration facility and the top of an impermeable layer, such as a seasonal high groundwater table. Per the 2012 SWMMWW, Volume III, Section 3.1.1, infiltration trenches may only be located in fill material placed and compacted under the direct supervision of a geotechnical engineer or professional civil engineer with geotechnical expertise. Based on our subsurface explorations, it is our opinion that these requirements cannot be met at the site. Given the presence of mottling, groundwater seepage, undocumented fill, and over-consolidated glacial till soils observed at the site, and the variability of the onsite soils, it is our opinion that the onsite infiltration of stormwater runoff generated by the proposed development is not feasible from a geotechnical standpoint. We recommend that the stormwater runoff generated by the proposed development be managed via alternative BMPs and stormwater management methods per the 2012 SWMMWW. All minimum setback and separation requirements and design criteria per the 2012 SWMMWW should be considered prior to the selection of a stormwater management facility. If minimum and separation setback requirements cannot be met at the site, the proposed stormwater system should be connected directly to the existing municipal stormwater system. Stormwa ter Pond The recently updated plans show the stormwater detention pond on the south side of the development (Tract A) will extend about 25 to 30 feet below existing grades. As proposed, the pond will have side slopes of 3H:1V. At the time our original explorations were completed, the Tract A was going to be an open space area. We only have explorations within the detention pond footprint, which extend down about 5 to 9 feet below grade and encountered approximately 8½ feet of undocumented fill over glacially consolidated soils. In order to evaluate the subsurface conditions and provide an opinion and geotechnical recommendations for the pond construction and the resulting slope configuration, GeoResources, LLC. should be retained to explore subsurface conditions to a depth of at least 5 feet below the proposed pond bottom. A minimum of three explorations should be performed in order to satisfy the requirements of the SWMMWW and we recommend at least one of the borings locations have a groundwater monitoring well installed. 160 337 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 15 EARTHWORK RECOMMENDATIONS Site Preparation All structural areas on the site to be graded should be stripped of vegetation, organic surface soils, and other deleterious materials including existing residences, ancillary structures, foundations or abandoned utility lines. Organic topsoil is not suitable for use as structural fill but may be used for limited depths in non-structural areas. Stripping depths ranging from 12 to 18 inches should be expected to remove these unsuitable soils. Thicker topsoil or organic debris may be encountered in areas of heavy vegetation or depressions. In addition to the removal of the topsoil, the undocumented fill encountered across the site should be removed or mitigated. Recommendations regarding the potential reuse of the undocumented fill and native soils are discussed in the “Suitability of On-Site Materials as Fill” section. Where placement of fill material is required, the stripped/exposed subgrade areas should be compacted to a firm and unyielding surface prior to placement of any fill. Excavations for debris removal should be backfilled with structural fill compacted to the densities described in the “Structural Fill” section of this report. We recommend that a member of our staff evaluate the exposed subgrade conditions after removal of vegetation and topsoil stripping is completed and prior to placement of structural fill. The exposed subgrade soil should be proof-rolled with heavy rubber-tired equipment during dry weather or probed with a ½-inch-diameter steel rod during wet weather conditions. Soft, loose or otherwise unsuitable areas delineated during proofrolling or probing should be recompacted, if practical, or over-excavated and replaced with structural fill. The depth and extent of over-excavation should be evaluated by our field representative at the time of construction. The areas of previously placed, undocumented fill material should be evaluated during grading operations to determine if they need mitigation; recompaction or removal. Structural Fill All material placed as fill associated with mass grading, utility trench backfill, under building areas, under retaining structures, or under roadways, should be placed as structural fill. The structural fill should be placed in horizontal lifts of appropriate thickness to allow adequate and uniform compaction of each lift. Structural fill should be compacted to at least 95 percent of MDD (maximum dry density as determined in accordance with ASTM D-1557), and the moisture content should be maintained within 2 percent of the optimum moisture content for compaction. The appropriate lift thickness will depend on the structural fill characteristics and compaction equipment used. We recommend that the appropriate lift thickness be evaluated by our field representative during construction. We recommend that our representative be present during site grading activities to observe the work and perform field density tests. The suitability of material for use as structural fill will depend on the gradation and moisture content of the soil. As the amount of fines (material passing US No. 200 sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult to achieve. During wet weather, we recommend use of well-graded sand and gravel with less than 5 percent (by weight) passing the US No. 200 sieve based on that fraction passing the 3/4-inch sieve, such as Gravel Backfill for Walls (WSDOT 9-03.12(2)). If prolonged dry 161 338 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 16 weather prevails during the earthwork and foundation installation phase of construction, higher fines content (up to 10 to 12 percent) may be acceptable. Material placed for structural fill should be free of debris, organic matter, trash and cobbles greater than 6-inches in diameter. The fines in the structural fill should be non-plastic. The moisture content of the fill material should be adjusted as necessary for proper compaction. Suitability of On-Site Materials as Fill During dry weather construction, the non-organic on-site outwash soil may be considered for use as structural fill; provided it meets the criteria described above in the “Structural Fill” section and can be compacted as recommended. If the soil material is over-optimum in moisture content when excavated, it will be necessary to aerate or dry the soil prior to placement as structural fill. We generally did not observe the site soils to be excessively moist at the time of our site visit. The previously placed, undocumented fill encountered across the site consists of a mixture of sand, silt, and gravel with construction debris. We do not anticipate these soils will be suitable for use as structural fill in their present condition because of their fines content and the presence of debris. The deeper, native glacial till soils encountered across the site generally consist of sand and gravel with variable amounts of fines. These soils are generally comparable to “Common Borrow” (WSDOT 9-03.14(3)) material and will be suitable for use as structural fill provided the moisture content is maintained within 2 percent of the optimum moisture level. We recommend that completed graded-areas be restricted from traffic or protected prior to wet weather conditions. The graded areas may be protected by paving, placing asphalt-treated base, a layer of free-draining material such as pit run sand and gravel or clean crushed rock material containing less than 5 percent fines, or some combination of the above. Erosion Control Weathering, erosion and the resulting surficial sloughing and shallow land sliding are natural processes. As noted, no evidence of surficial raveling or sloughing was observed at the site. To manage and reduce the potential for these natural processes, temporary and permanent erosion control measures should be installed and maintained during construction or as soon as practical thereafter to limit the additional influx of water to exposed areas and protect potential receiving waters. These construction practices should mitigate the potential erosion hazard at the site. We recommend erosion protection measures be in place prior to the start of grading activities at the site. Erosion hazards can be mitigated by applying Best Management Practices (BMP’s) outlined in the 2012 Washington State Department of Ecology’s (DOE) Stormwater Management Manual for Western Washington. If the recommended erosion and sediment control BMPs are properly implemented and maintained, it is our opinion that the planned development should not increase the potential for erosion of the site. Wet Weather and Wet Condition Considerations In the Puget Sound area, wet weather generally begins about mid-October and continues through about May, although rainy periods could occur at any time of year. Therefore, it is strongly encouraged that earthwork be scheduled during the dry weather months of June through September. Most of the soils encountered across the site contain sufficient fines to produce an unstable mixture when wet. Such soil is highly susceptible to changes in water content and tends to 162 339 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 17 become unstable and impossible to proof-roll and compact if the moisture content exceeds the optimum. In addition, during wet weather months, the groundwater levels could increase, resulting in seepage into site excavations. Performing earthwork during dry weather would reduce these problems and costs associated with rainwater, construction traffic, and handling of wet soil. However, should wet weather/wet condition earthwork be unavoidable, the following recommendations are provided: • The ground surface in and surrounding the construction area should be sloped as much as possible to promote runoff of precipitation away from work areas and to prevent ponding of water. • Work areas or slopes should be covered with plastic. The use of sloping, ditching, sumps, dewatering, and other measures should be employed as necessary to permit proper completion of the work. • Earthwork should be accomplished in small sections to minimize exposure to wet conditions. That is, each section should be small enough so that the removal of unsuitable soils and placement and compaction of clean structural fill could be accomplished on the same day. The size of construction equipment may have to be limited to prevent soil disturbance. It may be necessary to excavate soils with a backhoe, or equivalent, and locate them so that equipment does not pass over the excavated area. Thus, subgrade disturbance caused by equipment traffic would be minimized. • Fill material should consist of clean, well-graded, sand and gravel, of which not more than 5 percent fines by dry weight passes the No. 200 mesh sieve, based on wet-sieving the fraction passing the ¾-inch mesh sieve. The gravel content should range from between 20 and 50 percent retained on a No. 4 mesh sieve. The fines should be non-plastic. • No exposed soil should be left uncompacted and exposed to moisture. A smooth-drum vibratory roller, or equivalent, should roll the surface to seal out as much water as possible. • In-place soil or fill soil that becomes wet and unstable and/or too wet to suitably compact should be removed and replaced with clean, granular soil (see gradation requirements above). • Excavation and placement of structural fill material should be observed on a full-time basis by a geotechnical engineer (or representative) experienced in wet weather/wet condition earthwork to determine that all work is being accomplished in accordance with the project specifications and our recommendations. • Grading and earthwork should not be accomplished during periods of heavy, continuous rainfall. We recommend that the above requirements for wet weather/wet condition earthwork be incorporated into the contract specifications. Construction Observation We recommend that GeoResources, LLC be retained to observe the geotechnical aspects of construction including stripping, processing of the undocumented fill, foundations, fill placement and compaction, and drainage activities. This observation would allow us to verify the subsurface conditions as they are exposed during construction and to determine that work is accomplished in 163 340 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 18 accordance with our recommendations. If conditions encountered during construction differ from those anticipated, we can provide recommendations for the conditions actually encountered. Additional Services As previously stated in the Stormwater Pond section, we recommend additional subsurface explorations be completed in the newly proposed pond area in order to evaluate the subsurface conditions to the full proposed pond depth. We anticipate 3 borings will be sufficient to appropriately describe the pond subsurface soils, and at least 1 of the borings should include a groundwater monitoring well, if groundwater is encountered. An addendum report will also be required to provide our recommendations and opinions based on the additional explorations. We can provide an additional scope and budget for these tasks at your request. LIMITATIONS We have prepared this revised preliminary report for use by Stowe Construction and other members of the design team, for use in the design of a portion of this project. The data used in preparing this report and this report should be provided to prospective contractors for their bidding or estimating purposes only. Our report, conclusions and interpretations are based on our subsurface explorations, data from others and limited site reconnaissance, and should not be construed as a warranty of the subsurface conditions. Variations in subsurface conditions are possible between the explorations and may also occur with time. A contingency for unanticipated conditions should be included in the budget and schedule. Sufficient monitoring, testing and consultation should be provided by our firm during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether earthwork and foundation installation activities comply with contract plans and specifications. The scope of our services does not include services related to environmental remediation and construction safety precautions. Our recommendations are not intended to direct the contractor's methods, techniques, sequences or procedures, except as specifically described in our report for consideration in design. If there are any changes in the loads, grades, locations, configurations or type of facilities to be constructed, the conclusions and recommendations presented in this report may not be fully applicable. If such changes are made, we should be given the opportunity to review our recommendations and provide written modifications or verifications, as appropriate.    164 341 of 628 StoweConst.56thAveS.RG.rev01.doc January 14, 2019 page | 19 We have appreciated the opportunity to be of service to you on this project. If you have any questions or comments, please do not hesitate to call at your earliest convenience. Respectfully submitted, GeoResources, LLC Carson Cheung, EIT Staff Engineer in Training Keith S. Schembs, LEG Dana C. Biggerstaff, PE Principal Senior Geotechnical Engineer CC:KSS:DCB/cc Doc ID: StoweConst.56thAveS.RGu.Rev01 Attachments: Figure 1: Site Vicinity Map Figure 2a: Site Vicinity Map Figure 2b: Site and Exploration Plan Figure 3: NRCS SCS Soil Map Figure 4: USGS Geologic Map Figure 5: Typical Wall Drainage and Backfill Detail Figure 6: IBC Appendix J Detail Appendix "A" – Subsurface Explorations Appendix "B" – Laboratory Results Appendix “C” – Previous Geotechnical Engineering Report 165 342 of 628 Approximate Site Location (map created from King County Public GIS iMap) Not to Scale Site Location Map Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure 1 166 343 of 628 Approximate Site Location (map created from King County Public GIS iMap) Not to Scale Site Vicinity Map Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F January 2019 Figure 2a 167 344 of 628 Approximate Site Location (map created from Preliminary Road and Drainage Plan prepared by Barghausen Consulting Engineering, Inc. dated January 11, 2019) Not to scale Site and Exploration Plan Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 DocID: StoweConst.56thAveS.F2b January 2019 Figure 2b Number and approximate location of test pits TP-1 TP-7 TP-3 TP-2 TP-101 (PIT-1) TP-4 TP-6 TP-106 TP-5 TP-104 TP-105 TP-102 (PIT-2) TP-103 168 345 of 628 Approximate Site Location Map created from Web Soil Survey (http://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx) Soil Type Soil Name Parent Material Slopes Erosion Hazard Hydrologic Soils Group Agc Alderwood gravelly sandy loam Glacial till 8 to 15 Moderate B Not to Scale NRCS Soils Map Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure 3 169 346 of 628 Approximate Site Location An excerpt from the Geologic Map of the Poverty Bay 7.5-minute Quadrangle, Washington by Derek B. Booth, Howard H. Waldron, and Kathy G. Troost (2003) Qvr Recessional outwash deposits Qvt Glacial till Not to Scale USGS Geologic Map Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure 4 170 347 of 628 Notes Typical Wall Drainage and Backfill Detail Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure 5 1. Washed pea gravel/crushed rock beneath floor slab could be hydraulically connected to perimeter/subdrain pipe. Use of 1” diameter weep holes as shown is one applicable method. Crushed gravel should consist of 3/4” minus. Washed pea gravel should consist of 3/8” to No. 8 standard sieve. 2. Wall backfill should meet WSDOT Gravel Backfill for walls Specification 9-03-12(2). 3. Drainage sand and gravel backfill within 18” of wall should be compacted with hand-operated equipment. Heavy equipment should not be used for backfill, as such equipment operated near the wall could increase lateral earth pressures and possibly damage the wall. The table below presents the drainage sand and gravel gradation. 4. All wall back fill should be placed in layers not exceeding 4” loose thickness for light equipment and 8” for heavy equipment and should be densely compacted. Beneath paved or sidewalk areas, compact to at least 95% Modified Proctor maximum density (ASTM: 01557-70 Method C). In landscaping areas, compact to 90% minimum. 5. Drainage sand and gravel may be replaced with a geocomposite core sheet drain placed against the wall and connected to the subdrain pipe. The geocomposite core sheet should have a minimum transmissivity of 3.0 gallons/minute/foot when tested under a gradient of 1.0 according to ASTM 04716. 6. The subdrain should consist of 4” diameter (minimum), slotted or perforated plastic pipe meeting the requirements of AASHTO M 304; 1/8-inch maximum slot width; 3/16- to 3/8- inch perforated pipe holes in the lower half of pipe, with lower third segment unperforated for water flow; tight joints; sloped at a minimum of 6”/100’ to drain; cleanouts to be provided at regular intervals. 7. Surround subdrain pipe with 8 inches (minimum) of washed pea gravel (2” below pipe” or 5/8” minus clean crushed gravel. Washed pea gravel to be graded from 3/8-inch to No.8 standard sieve. 8. See text for floor slab subgrade preparation. Materials Drainage Sand and Gravel ¾” Minus Crushed Gravel Sieve Size % Passing by Weight Sieve Size % Passing by Weight ¾” 100 ¾” 100 No 4 28 – 56 ½” 75 – 100 No 8 20 – 50 ¼” 0 – 25 No 50 3 – 12 No 100 0 – 2 No 100 0 – 2 (by wet sieving) (non-plastic) 171 348 of 628 IBC Appendix J Detail Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 DocID: StoweConst.56thAveS.F September 2018 Figure 6 172 349 of 628 Appendix A Subsurface Explorations 173 350 of 628 SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP SYMBOL GROUP NAME COARSE GRAINED SOILS More than 50% Retained on No. 200 Sieve GRAVEL More than 50% Of Coarse Fraction Retained on No. 4 Sieve CLEAN GRAVEL GW WELL-GRADED GRAVEL, FINE TO COARSE GRAVEL GP POORLY-GRADED GRAVEL GRAVEL WITH FINES GM SILTY GRAVEL GC CLAYEY GRAVEL SAND More than 50% Of Coarse Fraction Passes No. 4 Sieve CLEAN SAND SW WELL-GRADED SAND, FINE TO COARSE SAND SP POORLY-GRADED SAND SAND WITH FINES SM SILTY SAND SC CLAYEY SAND FINE GRAINED SOILS More than 50% Passes No. 200 Sieve SILT AND CLAY Liquid Limit Less than 50 INORGANIC ML SILT CL CLAY ORGANIC OL ORGANIC SILT, ORGANIC CLAY SILT AND CLAY Liquid Limit 50 or more INORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT CH CLAY OF HIGH PLASTICITY, FAT CLAY ORGANIC OH ORGANIC CLAY, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: SOIL MOISTURE MODIFIERS: 1. Field classification is based on visual examination of soil Dry- Absence of moisture, dry to the touch in general accordance with ASTM D2488-90. Moist- Damp, but no visible water 2. Soil classification using laboratory tests is based on ASTM D2487-90. Wet- Visible free water or saturated, usually soil is obtained from below water table 3. Description of soil density or consistency are based on interpretation of blow count data, visual appearance of soils, and or test data. Unified Soils Classification System Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure A-1 174 351 of 628 Test Pit TP-101 (PIT-1) Location: NE corner of parcel 9262800295 Approximate Elevation: 431’ Depth (ft) Soil Type Soil Description 0 - 0.5 - Brown topsoil/crushed rock (loose, moist) 0.5 - 2.0 SM Brown silty SAND with gravel and some to trace organics (medium dense, originally moist, saturated from infiltration testing) (fill) 2.0 - 3.0 - Dark brown relict topsoil with abundant organics (loose, saturated from infiltration testing) 3.0 - 4.0 SM Reddish brown with iron oxide staining/mottling silty SAND with gravel (loose to medium dense, moist) (weathered till) 4.0 - 5.0 SM Brown grey silty SAND with gravel (medium dense becomes dense, moist) (till) Terminated at 5 feet below ground surface. Iron oxide staining/mottling observed at 3 feet below existing ground surface. No groundwater seepage observed at the time of excavation. Some minor caving observed at 2.5 feet below existing ground surface (infiltration testing) Test Pit TP-102 (PIT-2) Location: NW corner of parcel 92682800313 Approximate Elevation: 420’ Depth (ft) Soil Type Soil Description 0 - 0.7 - Dark brown topsoil with roots and organics (loose, moist) 0.7 - 2.6 GP-GM Brown grey with some iron oxide staining/mottling poorly-graded GRAVEL with silt and sand (loose to medium dense, originally moist, saturated from infiltration testing) 2.6 - 5.0 GM Grey silty GRAVEL with sand (dense, saturated likely from infiltration testing, become moist at about 3.5 feet below existing ground surface) (gravely till?) Terminated at 5 feet below ground surface. Some iron oxide staining/mottling observed at 1.2 feet below existing ground surface. No groundwater seepage observed at the time of excavation. No caving observed at the time of excavation. Logged by: CC Excavated on: September 25, 2018 Test Pit Logs Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure A-2 175 352 of 628 Test Pit TP-103 Location: South central portion of parcel 9262800313 Approximate Elevation: 419’ Depth (ft) Soil Type Soil Description 0 - 1.0 - Dark brown topsoil with roots and organics (loose, dry to moist) 1.0 - 3.0 SM Brown grey with iron oxide staining/mottling silty SAND with gravel (loose to medium dense, dry to moist) (weathered till) 3.0 - 4.5 SM Grey silty SAND with gravel (dense, dry to moist) (till) Terminated at 4.5 feet below ground surface. Iron oxide staining/mottling observed at 1 foot below existing ground surface. No groundwater seepage observed at the time of excavation. No caving observed at the time of excavation. Test Pit TP-104 Location: North central portion of parcel 9262800313 Approximate Elevation: 424’ Depth (ft) Soil Type Soil Description 0 - 1.0 - Dark brown topsoil with roots and organics (loose, dry to moist) 1.0 - 2.0 SM Brown grey with iron oxide staining/mottling silty SAND with gravel (loose to medium dense, dry to moist) (weathered till) 2.0 - 5.5 SM Grey silty SAND with gravel and cobbles (dense, dry to moist) (till) Terminated at 5.5 feet below ground surface. Iron oxide staining/mottling observed at 1 foot below existing ground surface. No groundwater seepage observed at the time of excavation. No caving observed at the time of excavation. Logged by: CC Excavated on: September 25, 2018 Test Pit Logs Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure A-3 176 353 of 628 Test Pit TP-105 Location: NE corner of parcel 9262800313 Approximate Elevation: 414’ Depth (ft) Soil Type Soil Description 0 - 1.0 - Dark brown topsoil with roots and organics (loose, moist) 1.0 - 2.5 SM Brown with iron oxide staining/mottling silty SAND with gravel and occasional boulder (medium dense, moist) (weathered till) 2.5 - 5.5 SM Grey silty SAND with gravel (dense, moist) (till) Terminated at 5.5 feet below ground surface. Iron oxide staining/mottling observed at 1 foot below existing ground surface. No groundwater seepage observed at the time of excavation. No caving observed at the time of excavation. Test Pit TP-106 Location: SE corner of parcel 9262800313 Approximate Elevation: 414’ Depth (ft) Soil Type Soil Description 0 - 1.0 - Dark brown topsoil with roots and organics (loose, moist) 1.0 - 2.0 GM Brown with iron oxide staining/mottling silty GRAVEL with sand and occasional boulder (medium dense, moist) (weathered gravely till?) 2.0 - 5.5 SM Brown grey silty SAND with gravel (dense, moist) (till) Terminated at 5.5 feet below ground surface. Iron oxide staining/mottling observed at 1 foot below existing ground surface. No groundwater seepage observed at the time of excavation. No caving observed at the time of excavation. Logged by: CC Excavated on: September 25, 2018 Test Pit Logs Proposed Residential Development 32727 – 56th Avenue South Auburn, Washington PN: 9262800295, 9262800320 & 9262800313 Doc ID: StoweConst.56thAveS.F September 2018 Figure A-4 177 354 of 628 Appendix B Laboratory Analyses 178 355 of 628 These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By: Particle Size Distribution Report PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 13.1 49.9 9.1 7.1 13.7 7.16 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM D 422 & ASTM C 117) Opening Percent Spec. *Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: TP-102, S-1 Sample Number: 095623 Depth: 2' Client: Project: Project No:Figure Brown poorly-graded GRAVEL with silt and sand 1 .75 .5 .3125 #4 #10 #20 #40 #60 #100 #200 100.0 86.9 68.7 57.0 37.0 27.9 22.4 20.8 12.5 9.4 7.1 NP NV NP GP-GM A-1-a 20.3975 18.2684 8.9716 6.6366 2.4341 0.2932 0.1662 53.98 3.97 10/2/2018 CC/NF KSS PM 9/25/2018 Mr. Byran Stowe StoweConst.56thAveS StoweConst.56thAveS PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) GeoResources, LLC Fife, WA 179 356 of 628 These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By: Particle Size Distribution Report PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 20.9 35.0 9.0 10.8 11.9 12.46 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM D 422 & ASTM C 117) Opening Percent Spec. *Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: TP-106, S-1 Sample Number: 095633 Depth: 1-3' Client: Project: Project No:Figure Brown silty GRAVEL with sand 1.25 1 .75 .5 .3125 #4 #10 #20 #40 #60 #100 #200 100.0 88.8 79.1 65.6 59.8 44.1 35.1 29.5 24.3 19.5 16.1 12.4 NP NV NP GM A-1-a 26.0204 22.6961 8.0962 5.7661 0.9212 0.1225 10/2/2018 CC/NF KSS PM 9/25/2018 Mr. Byran Stowe StoweConst.56thAveS StoweConst.56thAveS PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) GeoResources, LLC Fife, WA 180 357 of 628 These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By: Particle Size Distribution Report PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 7.9 31.1 11.8 16.4 18.6 14.26 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM D 422 & ASTM C 117) Opening Percent Spec. *Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: TP-106, S-2 Sample Number: 095634 Depth: 3-5.5' Client: Project: Project No:Figure Grey silty SAND with gravel 1 .75 .5 .3125 #4 #10 #20 #40 #60 #100 #200 100.0 92.1 83.4 75.7 61.0 49.2 40.7 32.8 24.9 19.1 14.2 NP NV NP SM A-1-b 17.2541 13.6730 4.4078 2.1209 0.3527 0.0845 10/2/2018 CC/NF KSS PM 9/25/2018 Mr. Byran Stowe StoweConst.56thAveS StoweConst.56thAveS PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) GeoResources, LLC Fife, WA 181 358 of 628 182 Attachment D-2 Critical Areas Report 359 of 628 January 14, 2019 Bryan Stowe PO Box 1054 Sumner, Washington 98390 RE: Critical Area Report – Carbon Trails City of Auburn, Washington SWC Job #17-216 Dear Bryan, This report describes our observations of jurisdictional wetlands, streams and buffers on or within 200’ of the proposed Carbon Trails Plat, located on Parcels#926280-0295, #0320& #0313 located between 51st Avenue SE and 56th Avenue SE in the City of Auburn, Washington (the “site”). The site consists of an 11.38 acre irregular shaped accumulation of 3 parcels, located within the NW ¼ of Section 14, Township 21 North, Range 4 East of the W.M. METHODOLOGY Ed Sewall of Sewall Wetland Consulting, Inc. inspected the site on December 4, 2017 and September 24, 2018. The site was reviewed using methodology described in the Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory, 1987), and the Western Mountains, Valleys and Coast region Supplement (Version 2.0) dated June 24, 2010, as required by the US Army Corps of Engineers and City of Auburn. Soil colors were identified using the 1990 Edited and Revised Edition of the Munsell Soil Color Charts (Kollmorgen Instruments Corp. 1990). Sewall Wetland Consulting, Inc. PO Box 880 Phone: 253-859-0515 Fall City, WA 98024 183 360 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 2 Above: Vicinity Map of the site. 184 361 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 3 OBSERVATIONS Existing Site Documentation. Prior to visiting the site, a review of several natural resource inventory maps was conducted. Resources reviewed included the National Wetland Inventory Map and the NRCS Soil Survey online mapping and Data and the King County iMap website with wetland and stream layers activated. Soil Survey According to data on file with the NRCS Soil Survey, the majority of the site is mapped as moderately well drained Alderwood soils of various slopes. Alderwood soils are not considered “hydric” or wetland soils. Above: USDA Soil Survey Map of the sit National Wetlands Inventory (NWI) According to the NWI map for the site, are no wetlands on or near the site. The closest wetland is approximately 1,000’ northwest of the site. 185 362 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 4 Above: National Wetlands Inventory Map of the site. WADNR Fpars Stream Mapping According the WDNR Fpars stream mapping of the site, there are no streams on or near the site. 186 363 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 5 Above: WDNR Fpars stream mapping. Washington Department of Fish and Wildlife Priority Habitats Data Search According to the WDFW Priority Habitat Website with Public access layers activated, there are no priority habitats or species points located on or near the site. 187 364 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 6 Above:WDFW Priority Habitats and Species Map of the area of the site. Field observations Uplands The site consists of a mix of mature douglas fir forest, and a disturbed shrub and sapling covered area near the north central part of the site. A single family home with a large shop building is located on the eastern side of the site. The forested areas of the site contain large douglas fir in the overstory with red huckleberry, Himalayan blackberry, stinging nettle, sword fern, salal, creeping blackberry, vine maple, indian plum and hazelnut in the understory. The central disturbed portion of the site appears to be old fill covered with weedy species such as Himalayan blackberry, scotch broom, some reed canary grass and alder and cottonwood saplings. Soil pits excavated within the upland areas revealed gravelly sandy loam as well as a gravelly fill material soils in disturbed areas with colors of 10YR 3/3-3/4. 188 365 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 7 Wetlands A single forested wetland was observed along the north edge of the site. This wetland is approximately 1 acre in size and discharges to a culvert located along the south end of the wetland. The location of the outlet of the culvert is unknown and was not observed on-site or south of the site, the logical outlet location. Wetland A “Wetland A” onsite consists of the south edge of the wetland which was flagged with flags A1-A8. The wetland extends off-site to the north and is approximately 1 acre in size based upon aerial photograph measurements. The wetland is vegetated with an overstory of red alder and pacific willow, with crabapple, hardhack and lady fern in the understory. Soil pits excavated within the wetland revealed a mucky gravelly loam with a soil color of 10YR 2/2 with few, fine, faint redox concentrations. Soils were inundated with 3” of standing ware during our December 2017 delineation of the wetland. Using the US Fish and Wildlife Wetland Classification Method (Cowardin et al. 1979), Wetland A would be classified as PFO1C (palustrine, forested, deciduous, seasonally flooded). Using the 2014 WADOE Wetland Rating system and rating the wetland as a depressional type wetland, this wetland scored a total of 16 points with 4 points for habitat. This indicates a Category III wetland. A Category III wetland with 4 habitat points in the City of Auburn (AMC 16.10.090.E.1) have minimum buffer width of 25’, and a maximum buffer of 50’ buffer measured from the wetland edge. Proposed Project The proposed project is the construction of a 43 lot residential plat with associated infrastructure. No impact to the Category III wetland or its associated 50’ buffer is proposed. 189 366 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 8 If you have any questions in regards to this report or need additional information, please feel free to contact me at (253) 859-0515 or at esewall@sewallwc.com . Sincerely, Sewall Wetland Consulting, Inc. Ed Sewall Senior Wetlands Ecologist PWS #212 Attached: Data sheets Rating Forms 190 367 of 628 Carbon Trails/#17-216 Sewall Wetland Consulting, Inc. January 14, 2019 Page 9 REFERENCES Cowardin, L., V. Carter, F. Golet, and E. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, FWS/OBS-79-31, Washington, D. C. Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual, Technical Report Y-87-1. U. S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, Mississippi. Muller-Dombois, D. and H. Ellenberg. 1974. Aims and Methods of Vegetation Ecology. John Wiley & Sons, Inc. New York, New York. Munsell Color. 1988. Munsell Soil Color Charts. Kollmorgen Instruments Corp., Baltimore, Maryland. National Technical Committee for Hydric Soils. 1991. Hydric Soils of the United States. USDA Misc. Publ. No. 1491. Reed, P., Jr. 1988. National List of Plant Species that Occur in Wetlands: Northwest (Region 9). 1988. U. S. Fish and Wildlife Service, Inland Freshwater Ecology Section, St. Petersburg, Florida. Reed, P.B. Jr. 1993. 1993 Supplement to the list of plant species that occur in wetlands: Northwest (Region 9). USFWS supplement to Biol. Rpt. 88(26.9) May 1988. USDA NRCS & National Technical Committee for Hydric Soils, September 1995. Field Indicators of Hydric Soils in the United States - Version 2.1 191 368 of 628 CARBON TRAILS Know what'sbelow.before you dig.CallR192369 of 628 CARBON TRAILSKnow what'sbelow.before you dig.CallR193370 of 628 WETLAND DETERMINATION DATA FORM - Western Mountains. Valleys* ami Coast Region Applicant/Owner: Investigators) _ Landform (hilislope, terrace, etc) Subregfon (LRR) Soil Map Unit Name: _ g& ST" . City/County:. . Sampling Date: , Sampling Point:. . Sedton, Township, Range _ . Lai. . Local relief (concave, convex, none).. , Long: . Slope (%):. . Datum:. . NWt classification:. Are climatic / hydrotogtc conditions on the site typical for this ttme of year? Yes Ho (tf no, explain in Remarks.) Are Vegetation , Soil . or Hydrology significantly disturbed? Are 'Normal Circumstances* present? Yas No Are Vegetation . Soil _______ or Hydrology naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS - Attach site map showing sampling point locations, transects, important features, etc. Hydrophyte Vegetation Present? Hydric Soil Present? Wetland Hydrology Present? Y«._£^o_. Yes No_ Is the Sampled Area within • Wetland? 1 Yu No Remarks VEGETATION - Use scientific names of plants. Tree Stratum (Plot ira _____ 1 nl'vvL r-^br—\ Absolute % Cover - fc* ... Dominant Indicator Species? Status *_c Seolinarenrob Stratum (Plot size: I . "Tola! Cover Hera Stratum (Plotuze . TSgW If -Jtttf. - Total Cover Woodv Vine Stratum (Plot size: _ % flare Ground in Herb Stratum _ Dominance Test worksheet: Number of Dominant Species That Are OBL. FACW. or FAC: (A) Total Number of Dominant Species Across AS Strata: Percent of Dominant Species j v&«_i That Are OBL. f ACW. or FAC: ..S Prevalence Index worksheet: , , Total % Cover of: _ Multiply t?y: OBL species FACWspeciss . FAC species FACU species UPL species Column Totab: . * 1 - -. x 3 * _ . x4= _ *5 = _ . (A) _ Prevalence Index * B/A * . Hydraphvj^Vegetaflon Indicators: _^0<)mmance Teat is >50% Prevalence Index is S3.Q! , , Morphological Adaptations' (Provide supporting data in Remarks or on a separate sheet) Wetland Non-Vascular Plants1 Problematic Hydroptiytic Vegetation' (Explain) 'Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytfe Vegetation Present? Yss US Army Corps of Engineers Western Mountains, Valleys, and Coast - interim Version SOIL Sampling Point: Profile Description: {Describe to the depth needed to document th* Indicator or confirm the absence of indicators.) Depth ...Mar*.. Miro«.. _^__Vz__ Color fi Redox Features^ Texture Type; C=Concentration. p^Degjelion. RM=ReducedMatrix, CS-CoyeredorC^j^S^ .Location: Pt=Ppre Lriing. M^Matrk Hydric Soft Indicators: (Applicable to all LRRs, unless otharwlss noted.) . HistosoHAI) . Histic Epipedon (A2) . Stock Histic (A3) . Hydrogen Sulfide (M) . Depleted Below Dark Surface (A11) . Thick Dark Surface (A1Z) . Sandy Mucky Mineral (S1) . Sandy Gieyed Matrix ($4) , Sandy Redox (S5) . Stripped Matrix <S6) . Loamy Mucky Mineral (F1) (except MLRA 1) . Loamy GJpyad Matrix (F2) De*«SdMatiU (F3> r^edox Dark Surface (F6) . Depleted Dart Surface <F7) . Redox Depressions (F6) Indicators for Problematic Hydric Soils': . 2 cm Muck (A10) . Red Parent Material (TF2) „ Other (Explain _i Remarks) indicators of hydrophylk; vegetation and wetland hydrology must be present, unless disturbed or probtematoc Restrictive Layer (if present): Type: Depth (inches):, Hydric Soil Present? Yes. HYDROLOGY Wetland Hvp>dfogy Indicators: lcUcators, (m|nirnum of one required; check all that apply) _Z Surface Water (A1) High Water Table (A2) Saturation (A3) _ Water Marks (Bt) Sediment Deposits (B2) Drift. Deposits (B3) _ Algal Mat or Crust (B4) Iron Deposits (86) Surface Soil Cracks (86) Inundation Visible on Aerial Imagery (B7) Sparsely Vegetated Concave Surface (Bfl) . Water-Stained leaves (89) (except MLRA 1,2,4A, and 46) . Salt Crust (B11) . Aquatic Invertebrates (813) . Hydrogen Sulfide Odor (CI) . Oxidized Rhizospheres along Living Roots (C3) . Presence of Reduced iron (C4) . Recent Iron Reduction in Tilled Soils (C6) . Stunted or Stressed Plants (D1) (LRR A) , Other (Explain in Remarks) Secondary, ImMcators (2 or.rnorc reflyyed) Water-Stained Leaves 189) (MUM 1, 2, 4A, and 4B) Drainage Patterns (B10) Dry-Season Water Table (C2) Saturation Visible on Aerial imagery (C9) Geomorahic Position (02) Shallow Aqurtard (03) FAC-Neulral Test <D5) Raised Ant Mounds (D6) (LRR A) Frost-Heave Hummocks (D7) Field Observations: Surface Water Present? Yes „ No Depth (inches): J Water Table Present? Yes _ No Depth (inches): Saturation Present? Yes _ No Depth (inches); Wetland Hydrology Present? Yes No . (includes capHtarv fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast - Interim Version 194371 of 628 3 Project-Slta:.. Apptlcarit/Owiwr: _ InvastiaMofts) Landform fnHWopa, Sl*r»gionaR«)' Soil Map Urrf Name. WETLAND DETERMINATION DATA FORM - WwtMT) Mountains, Valteys. and Coast Rofllon C<*~W- T>«~ If CHICax*: Av^VS~/>J SWnoDat.- I T-~ *j ~1 ^ _ Sampling Dane _ . Samp-wvg Point' . . Secffon. Township, Rang*: . Local relief (concave, convex, none);. Long: Stale- ^VA . Slope {%);_ 1 clasvftcatiori:, Are cferwrtic / hytiroJogic cc*KrteortS on the site typical for this Ttme of year? Yes__j^_No (If no, explain in Remarks) Are Vegetation , SoK . or Hydrology significantly disturbed? Are "Normal Circumstances* present? Yes , No Are Vegetation , Sofl ..„,.,...,.. or Hydrology naturally problematic? <tf needed, explain any answers in Remarks) SUMMARY OF FINDINGS - Attach site map showing sampling point locations, transacts, important features, c HydroohySeVepetstk-m Present? Hydric Son Present? Vlnaiand Hydrotogy Present? Yes Yes Yes No ^ Jt tha Sampled Ami within I Wetland? Ye* No Rat-nark* VEGETATION - Use scientlfle names of plants. _ (Ptotefta: Absolute St. Cover Dominant Inaicatar ma _» Total Cover PA I (Plot SUA: ij * i «Totai Cover Woodv Vine Stratum (Ptot size:. % Bare Ground in Herb Stratum _ Doa&iancs fast worWiset: Nwtber of Dominant Species That Are OBL, FACW. or FAC: Total Number of Dominant Species Across All Strata: Percent of Dominant Speojes That Aw OBL, FACW. or FAC; m (B) (A®) Prevaisnce In-da* wrtcsh-eet: Total %Cowr of: MuHiPlvbv: OBL species FACW species . FAC species . FACU species . 1 spades , Column Total*. , *1 x5» . .(A) . . (B) Prevalence Index * B/A » . Hydrophytfe Veo^rtatton Indicators: Owrwrence Test to >50% Prevalence Index is £3 0T Morphological Adaptations' (Provide sapportirig data; in ftenierfcs or on a separate sheet) Wetland Non-Vaacutar Plants' Problematic Hyefrophytic Vegetation' (Explain) 'indicators of hydric soil and wetland hydrology must be present, untess disturbed or problematic Vegetatton US Army Corps of Engineers Wast am Mountains. Valleys, and Coast - Interim Version SOIL Sampling Point: Profile DascHptton; (Desc*^ tothe depth nesdad todwmiWntth* MlcaW or cMfirm the absence erf Indicators.) Remarks 'Type: C^Coneemraiion, t>Deotelipn. RM-^aduosd Matrix, CS-Covered or Coaled Sand Grains. ,, ^Location:, Pt°Pora tmina t^Matrk, Hydrtc Soil Indtoetofs: (Applicable la a HiatosoKAD _ HWfcE|jipedon<A2> BoK*HHIio<A3l HydrojenSul»o»(A4] Depleted BatowDartcSurtaceCAU) Tnx* Dark Surfaca (A12) Sandy Mucky ntnersl (St) Sandy Gler°dM«lrr»i&l) t LRRa. unless otherwise noted.) Sandy Redox (S5> Skipped Matrix (So) Loamy Mucky Mineral (F1) (except MLRA 1) Loamy Gieyed Matrix (F2) _ Depleted Ms«1x(F3) Redox Oar* Surtaoe (F6> Depleted l>*8tir6ice(F7> Redox Depressions (F8) trxtteators tor Probfamatlc Hydric SOHS 2onMuck(A10) n-sd Parent Material (TF2) Other (.Explain in Remants) :^idxjators of hydraphyHc veoetation and watlar)d hydrolooy must be present, unless distiirtjed or problematic. Restrictive Layer (If present): Type: Oeoth ttnehea): Hydric Soil present? Yes _ Wo ' ^ Remarks: HYDROLOGY WeOend Hydrotojy ItxDOitoni: Sdrteos Water (A1) High Water T«*le(A2> Saturation <A3) _ Water Marks (Bl I Sediment Deposits (B2) Orttt Deposits (B3) A)oalMatorClust(M) ban Deposits <B5) _ Surlam Son Cracks (86) lmmdlllionVls«)le on Aerial lnageiy(B7) Sparsely Vegels^ Crjnrave Slinaos <88) _ Water-SlalruW Leaves IBs) (except MLRA 1,2,<A.and4e) Sa«Crtist(B1l) Aquatic rnvertebrates (813) _ HydroaanSu«deOdor(C1) OxuiizsdRhiiospnMMlrtongLtariQ , Presence of Reduced tron(C4) Recant Iron Reduction rnTIUcd Sons (08) _ SHinledwStlss»edPllintj(D1)(U«RA) Omer(E)vlalninRamiala) awndary Inacatoe B yrecxe fegurej.) _ Water-Stained Leaves IBB| (MLRA t, 3, 4A, and SB) Dralnaoe PaUems(BtO) Ory-Saason Watm Table (C2I _ 8atunriionVlsa^onAenaltmage(y(CS) _ Geofnorphic Posroon (02) ShaBcwAisiiiatd (03) _ FAC.NeutralT«st(D5) _ RaWK)AT7lMourids(06)(LRRA) Fn«4le«veHumrnoci(s(OT) Field Ooservetians: Suriaos Water Present? Wawt Table Present? Saturation Pwasnt? (tneluoas capHam Wnoe) Wetland Hydrology Present? Yes. Describe- Recorded Data (stream gauge, monitgdna well, aerial photos, previous itisoections), ft available: Remarks* US Army Corps of £ngjneers Western Mountains, Valleys, and Coast - trterim Version 195372 of 628 PrajectrSiB):. WETLAND DETERMINATION DATA FORM - Western Mountains, Valleys, and Coast Region App6cant/r>*nar: lnvw%rtor{«) ___ . Samptmg Data-_ Sampkng Point . . Section. Tovwwhip, Ran&»: _ Landform (hiMsiope, torsoa. etc): Stjtoagton (LRR) Soil Map Unit Name:_ . Local relief (concava, convex, none): „ Long: . NW1 aassftatlon:. Aradinietio/hvorologlccc«KWio^ Yes — Wo (If no, explain in Remarks.) Are Vegetation ,Soit ^wHyAotagy s^tr-aneydisturbed? Are*Norntatr^cwretaocas'prssent? Ye*_J Are Vegetation .Sott^ , or Hydrology naturally pmblenianc? (It needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Hyo>ophyt»c Veo^taten Present? Hydric Soil Present? Wetland Hyorotooy Present? _le£?™ ____*»-''" No -S" No__Z M the Sampled Ann within a Wetland? Yes No Remarks VEGETATION - Use sclentifie t tame 1 of plants. Ttse Stratum (Ptolsize;, Absolute % Soger. L>m»nant Indicator 5 gftlyij * Total Cover Hei-b (Plot axe ...t ,;.»g, 3 => TotaJ Cover ^2 Wjc^vyiaSIri^ {Ptotsoe:. % Bare Ground in Herb Stratum DMittoajtee Test wwttshaefc ' Number of Dominanl Species That Are 081. FACW. or FAC; Total Number of Dominant Spades Across All Strata: Pe-rxwvt of Dominant Species That Are OBI, FACW, or FAC: Prevalence Index wortonsst: tVfutyjply bv: OBI species FAeWspeefts , FAC species _ FACU species . UPL apectes _ Column Totab: . . (A) . Prevalence index »B/A« Myo^SJBcVeS j^Uoroinence 7 V*98tabon Indicators: Test is >80% Pmvatenoe Index is S3 0T Moroboiog^cai Adaptations' (Provide supporting data in RernerHs or on a separate sheet) Wetland Non-Vascular Plants' Problems!*: Hydrophytic Vec/staton1 (Expiatn) indfcators of hydnc soil and wetland hydrology must be present, unless disturbed or proWematoc Hydrophyfio Ve«Btatton Prseent? US Army Corps of Engineers Western Mountslrta. Valleys, and Coast - Interim Version 'Type: c-<frncatttnjtaon. p»Dep|ejion. RM-pReduoed Matrix, CS'Covered or Coated Sand Grams. location: PL"Pow Lwing, M^Matrit, Hydnc SOU Iridlcators: (AppncaMe to all LRRs, unless othstwlM noted.) Sandy Redox (SS) Stripped Matrix (S6) Loamy Mucky Mineral (Ft) (except MLRA 1) Loamy Sieved Matrix (F2) _ Depleted Matrix (F3) Redox Dark Surtace(P6) Depleted Dark Surface (F7) Redox Depressions (FB) »(A1> . «itic6pp«Oon(A2) . Black Mslic (A3) . Hydrogen SuHde(M) . Depleted tfck>wf^Si»<at»(A1t) . Thii* Die* Surface (A12) . Sandy Mucky Mineral (S11 Indicators tor Problematic Hydric So*' _ 2cmMuck(A10) Red Parent Material (TF2) Other (Explain xt Romarits) -Ntidtoetrjrs of hydrophyte vegetation and wetland hydtology must bs present tiTtessdatiirtwytorprobB^ Restrictive Layer (If present): Type: Depth (Inches): Hydric Soil Present? Yes Ho ^ Remarks: HYDROLOGY WeOand Hydrology Indicators: Primary WjceWrg MnyjtaT.ctr^ all rhy apply) Surface Water (A1) High Water Tat* (A2) Saftaatlon (A3) _ Water Marks (B!) Serfcneni Deposits (B2) ._ »m Deposits <B3) Algal Mat or Crust (B<) Iron Deposits (B6) Surface So) Cracks (B8) Inunrjation VniWe on Aerial Imageiy (87) SparsetyVagata)odCi>nM«BSunaoi<BS) _ Water-Stelrwd Leaves (BS) (except MLRA 1.2.4A. «nd<B) Salt Crust (Btl) Aq^lic Inwirhbratet (BI3I Hydrogen SuHirJe Odor (C1) OxidiswtRhizospherttsirkxtgLivi^ . Presence of Reduced Iron (C«) Recent don Reductionm Tilled Soils (CS) _ l*n«dwStte5SSdF1e^(OT)(U»JlA) Omar (Explain in Remarks) Secondary Irxticatora (2 or-more tBoured'l Water-Stained leaves IBS) (MLRA 1.1, 4A, and SB) Drainage Patterns (B10) Ory^aason Water Table (C2) _ SatjJ^at^on^l1sibleonAari«irnar^ „ Gcomorphic Position (D2) Shallow Antrtard (03) FAttsr!utralT«st(DS) _ Ratsod Ant Mounds (06) (LRR A) Frost-Heave Hummocks (0?) Field Observations: Suifaos Water Present? Yes Water Tat* Present? Yes Saturation Present? Yes (includes capjfjaiv MtlflB) witace(t») j Wo j^yx Deps^jlttcnas): Onchee): Depth I Inches): Wetland Hydrology Pr««ent7 Yos_ bescnba Recorded Dau) (stream gauge, rrwnitonrig trvefl, aeriat photos, previous jrtacections), i Remarks: US Army Corps of Engirteers Western Ivkjuntains, Valleys, and Coast - Interim Version 196373 of 628 WETLAND DETERMINATION DATA FORM - Western Mountains, Vallays. and Coast Region Projects** AswjBMntrOwnen . Investiowiorfs). . CiyCounty:. t Secltan. Township, Rang*: _ Uandform (hMstope, terraoa. etc ) Subregkm (LRR) Soil Map Unit Name._ . Local relief (concave, convex, none);_ long: . Slope , NW1 dassiftcsfton:. Am cfimatic,' hyrlroloojc condft»oo« on the srtt typical for this rtme of year? Yes r^\ (If no, eipJatn in Remarks.) Are Vagetetion So* ,or Hydrolooy staniftcantfy oHBbjreea"' Are "rtomai Ctrcurrstetnces* peasant? Yes No Are Vegetation , Son „ , or Hydrology naturally prabtematic? <tf needed, explain any answers in Ftemarits.) SUMMARY OF FINDINGS - Attach sit* map showing sampling point locations, transacts, important fsaturas, etc. t-rydraphytie Vegetation Present? Yes •Is the Sampled Anu Hydric Soli Present? Yes No -^t^ edStnatWetland? Yes No Wetland Hyotology Ptesent? res . N° ^ Yes Remark* VEGETATION - Use scientific names of p lants. tomfoance Test workefieet: t>fc)imber of Dominant Species That Are OBL. FACW. or FAC: Total Number of Dominant Spades Across AH Strata: Percaivt of Dvrninent Spaas* That Are 1361, FACW, or FAC: TreeBfratom (PJptaiza: } J&£fl5«L 3BHS3S&1 ®Bpi9 Absolute Dominorrt Indicator SssTWS^Stnsjjini (Pi a. gc^tt^ •Total Covet I'M. Hem Stratum (Plot aire:. 3 m (Afflt Prevalence Index worksheet: ToMft ftHHT of. WtfMvyr-OBl spades FACWspedn . FACs FACUsi UPts Column Totals; . x1 * >2-x3»_ **' . «S" . . (A) . Prevalence Index » bvA • . Hydrophyth: Vegetation Indicators: OomtnsfioeTeells>t30% Prevalence Indexis S3 01 M«|)tic4ogresl Adaptations' (Provide supporting data in Remertts or on a separate sheet) _ VVetlsrid Nonvascular Plants' Problematic Hydrophyte Vsgetaaon' (Explain) ^cscetors of hydric soil and wetland hydtafer# must be present, unless disturbed or problematic. V»fl9frVinpata|unt (Ptotsue:. % Bars Ground In Herb Stratum ^ US Army Corps of Engineers Western Mountetns. VaKeys. and Coast - Interim Version SOIL Sampling Point: PToflHi Description- (Pescrtbe to the depth needed to document the IrioHcatc^w confirm the absence of indicators.) Depth Mjife frerteFam'W. Itnchasi Ctforlmgjstl . Type' „\JK. Temwt Remark; sow V/^T 'Type: C^ortcenlnrtiqn, l>Depletroa PJJ ^Location: PL-Pore Union. M»Matrtt. Hydric Son Irxticstors: (AppScable to all LRRs, unless othsrwtst noted.) Hstoeol (At) _ Hls1iceplpst)0fi(A2) Star* HUSc (A3) Hydrogen SuMd*(M) Depl»lerjBeio«C»rt Surface (A11) Th** Dattt Surface (A12) Sandy Mucky Mmerai (S1) _ StnXfyGejyedMetofS^ Sandy Redox (S5) _ Stripped Matrix (So) Loamy Mucky Mineral (F1) (sxcspt MLRA 1) UxmiyGkiyed Matrix (F2) DspleWd Matrix (F3) Redox Dark. Surface (F0) Depleted Dark Surface (FT) Redox Depressions (F8) Indicators tor Problematic Hyetrtc Sous': 2 cm Muck vMO) Red Parent Materiel (TF2) „ Other (Explain in Remarks) "WScators of hydtapbyttc vegetation and wetland hydrology must ba present, unless drsturted or preblamabc. Restrictive Layer (If present): Type: Depth (Inches):. II Present? Yes. HYDROLOGY °1mifT'nlf^i(iTitfrlinmo'vn^ tr»ffr tflh¥'i"i'¥ Surface Water (A1) High. Water Table (A2) Saturation (A3) Water Marks <B1> _ Sediment Deposes (B2) Drift Deposit" (69) AJgM MM or Crust (84) lK»t Deposits (Bfi) Surface Soil Cracks (86) intatrtation Visible on Aerial ttltaoary (87) . Watar-Stalned Leaves [B91 (except MLRA 1.2,4A,and4B) . SsBCnjst(BH) . Aquatic rnvertebrates (813) . Hydrogen Sulfide Odor (CI) . Oxidized fti&Kpneres along Lrving Roots (C3) . Presence tfRerJticsd Iron (Cn) . Recent Iron Reduata m Tilled Soils (C8) . Slunted 01 Stressed PtontsfDl) (LRR A) . Other (explain » Remarks) Seoondarv Inacaaxs (2 or mora raoutaal WaMr-Stamad Leaves (B9) (MLRA 1.3, <A. and <B) Drainage Patterns (810) Dry-Season Walrn Table (C2) Sawrsbwr visible on Aerial Imagery (C«) Geomorphic Position (D2) Shs»c«Agu«ard(D3) _ FAr^Neutral Test (D5) Raised Ant Mounds (06) (LRR A) Frost-Heave Hurnmocfce (07) Field Obssrvations: Surface Water Present? Yes No _^epm fitches) Water Table Present? Yes No _^JBapth (inches) Saturation Pr»s«nt7 Yes Ho Depth (inches) includes catxlarv trtwa) Wetland Hydrology Praeent7 Yax Mo fteseilbe P^KunMrMa(streani gauge, morti^^ rt available: US Army Corps of Engineers Western Mountains, Vatteys, and Coast - Interim Version 197374 of 628 Wetland name or number RATING SUMMARY - Western Washington Name of wetland (or ID «): ^ *"•«»».«. * ' ' fa JPate of site visit: _V_? ^ " Ce^- Jj Trained by Ecology?^Yes ing T~'t 11 ^Wetland has multiple HGM classes?. Rated by C<^- JJ Trained by Ecology ?-^Yes No Date of training, HGM Class used for rating T^e p > ^Wetland has multiple HGM classes? NOTE: Form is not complete without the figures requested (figures can be combined). Source of base aerial photo/map OVERALL WETLAND CATEGORY i-T. (based on functionsj^orspecial characteristics ) 1. Category of wetland based on FUNCTIONS Category I - Total score = 23-27 Category II - Total score =20-22 Category III - Total score =16-19 Category IV - Total score = 9-15 FUNCTION Improving Water Quality Hydrotoglc Habitat Grde the appropriate ratinfis Site Potential H » &>.K Landscape Potential H Q&J L H M(X) Value 3) M L H L H M L,'' TOTAL Score Based on Ratings u I; . 0 2. Category based on SPECIAL CHARACTERISTICS of wetland Score for each function based on three ratings (order of ratings is not important) 9 = H,H,H 8=H,H,M H,H,L H,M,M H,M,L M,M,M H,L,L M,M,L M,L,L L,L,L CHARACTERISTIC CATEGORY Estuarine I II Wetland of High Conservation Value 1 Bog 1 Mature Forest 1 Old Growth Forest 1 Coastal Lagoon i II Interdunal i ii III jy' None of the above Wetland Rating System for Western WA: 2014 Update Rating Form - Effective (anuary 1,2015 1 Wetland name or number Maps and figures required to answer questions correctly for Western Washington Depressional Wetlands Map of: To answer questions: Figures Cowardin plant classes D 1.3, H 1.1, H 1.4 Hydroperiods D 1.4, H 1.2 Location of outlet {can be added to map of hydroperiods) D 1.1, D 4.1 Boundary of area within ISO ft of the wetland (can be added to another figure) D 2.2, D 5.2 Map of the contributing basin D4.3, D5.3 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin {from Ecology website} D 3.1, D 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) D3.3 Riverine Wetlands Map of: To answer questions: Figure t Cowardin plant classes H 1.1, H 1.4 Hydroperiods H1.2 Ponded depressions Rl.l Boundary of area within 150 ft of the wetland (can be added to another figure} R2.4 Plant cover of trees, shrubs, and herbaceous plants R 1.2, R 4.2 Width of unit vs. width of stream (can be added to another figure) R4.1 Map of the contributing basin R 2.2, R 2.3, R 5.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) R3.1 Screen capture of list of TMDLs for WRIA in which unit is found (from web) R 3.2, R 3.3 Lake Frinee Wetlands Map of: To answer questions: Figure* Cowardin plant classes Ll.l, L4.1, H1.1.H1.4 Plant cover of trees, shrubs, and herbaceous plants L1.2 Boundary of area within 150 ft of the wetland (can be added to another figure) L2.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) L 3.1, L 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) L3.3 Slope Wetlands Map of: ' To answer questions: Figure* Cowardin plant classes H 1.1, H 1.4 Hydroperiods H1.2 Plant cover of dense trees, shrubs, and herbaceous plants S1.3 Plant cover of dense, rigid trees, shrubs, and herbaceous plants (con be added to figure above) S4.1 Boundary of 150 ft buffer (can be added to another figure) S 2.1, S 5.1 1 km Polygon: Area that extends 1 km from entire wetland edge - Including polygons for accessible habitat and undisturbed habitat H2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) S 3.1, S 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) S3.3 Wetland Rating System for Western WA: 2014- Update Rating Form - Effective January 1,2015 2 198375 of 628 Wetland name or number HGM Classification of Wetlands in Western Washington For questions 1-7, the criteria described must apply to the entire unit being rated. If the hydrologic criteria listed in each question do not apply to the entire unit being rated, you probably have a unit with multiple HGM classes. In this case, identify which hydrologic criteria in questions 1-7 apply, and go to Question 8. 1. Are the water levels in the entire unit usually controlled by tides except during floods? , NO-goJs^ YES-the wetland class is Tidal Fringe-go to 1.1 1.1 Is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? NO - Saltwater Tidal Fringe (Estuarine) YES - Freshwater Tidal Fringe If your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. If it is Saltwater Tidal Fringe it is an Estuarine wetland and is not scored. This method cannot be used to score functions for estuarine wetlands. 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. Groundwater and surface water runoff are NOT sources of water to the unit. NO-go to3 YES-The wetland class is Flats If your wetland can be classified as a Flats wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet all of the following criteria? The vegetated part of the wetland is on the shores of a body of permanent open water (without any plants on the surface at any time of the year) at least 20 ac (8 ha) in size; _At least 30% of the open water area is deeper than 6.6 ft (2 m). NO - go to 4 YES - The wetland class is Lake Fringe (Lacustrine Fringe) 4. Does the entire wetland unit meet all of the following criteria? _The wetland is on a slope [slope can be very gradual), The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without distinct banks, The water leaves the wetland without being impounded. NO - go to 5 YES - The wetland class is Slope NOTE: Surface water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <3 ft diameter and less than 1 ft deep). 5. Does the entire wetland unit meet all of the following criteria? The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river, The overbank flooding occurs at least once every 2 years. Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,201S 3 Wetland name or number NO - go to 6 YES - The wedand class is Riverine NOTE: The Riverine unit can contain depressions that are filled with water when the river is not flooding 6. Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year? 77i/s means that any outlet, if present, is higher than the interior of the wetland. NO - go to 7 YES - The wedand class is Depressi^naT^^*^ 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding? The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. NO - go to 8 YES - The wetland class is Depressional 8. Your wedand unit seems to be difficult to classify and probably contains several different HGM classes. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a Depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN TH E UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within the wetland unit being scored. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the HGM class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. HGM classes within the wetland unit being rated HGM class to use in rating Slope + Riverine Riverine Slope + Depressional Depressional Slope + Lake Fringe Lake Fringe Depressional + Riverine along stream within boundary of depression Depressional Depressional + Lake Fringe Depressional Riverine + Lake Fringe Riverine Salt Water Tidal Fringe and any other class of freshwater wetland Treat as ESTUARINE If you are still unable to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 4 199376 of 628 Wetland name or number DEPRESSIONAL AND FLATS WETLANDS Water Quality Functions - Indicators that the site functions to improve water quality D 1.0. Does the site have the potential to improve water quality? D 1.1. Characteristics of surface water outflows from the wetland: Wetland is a depression or flat depression (QUESTION 7 on key) with no surface water leaving it (no outlet). points = 3 Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outlet. "CjointsfJV Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing points = 1 Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch. points = 1 D 1.1. Characteristics of surface water outflows from the wetland: Wetland is a depression or flat depression (QUESTION 7 on key) with no surface water leaving it (no outlet). points = 3 Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outlet. "CjointsfJV Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing points = 1 Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch. points = 1 D 1.2. Uje. soil 2 in below the surface (or duff laverl is true day or true organic (use NRCS definitionsj.tes = 4 No = 0 0 1.3. Characteristics and distribution of oersistent olants (Emereent. Scrub-shrub, and/or Forested Cowardin classes): Wetland has persistent, ungraded, plants > 95% of area ,^points=>> Wetland has persistent, ungrazed, plants > K of area points = 3 Wetland has persistent, ungrazed plants > Vio of area points = 1 Wetland has persistent, ungrazed plants < Vio of area points = 0 <• D 1.4. Characteristics of seasonal Dondine or inundation: This is the area that is ponded for at teast 2 months. See description in manual. Area seasonally ponded is > S4 total area of wetland points = JL.J, Area seasonally ponded is > % total area of wetland points = 2 Area seasonally ponded is < K total area of wetland points = 0 U Total for D1 f Add the points in the boxes above n Rating of Site Potential If score is: 12-16 = H J^6-11 = M 0-5 = 1 Record the rating on the first page D 2.0. Does the landscape have the potential to support the water quality function of the site? _ D 2.1. Does the wetland unit receive stormwater discharges? Yes = l llg = 0 ^ 01.1. Is> 10% of the area within 150 ft of the wetland in land uses that generate pollutants? Yes = 1 /NO = Q3 a D 2.3. Are there septic systems within 250 ft of the wetland? C Yes =J3»o = 0 ' D 2.4. Are there other sources of pollutants coming into the wetland that are not listed in questions D 2.1-D 2.3? Source Yes^i"~No3S^ c) Total for D 2 y Add the points in the boxes above \ Rating of Landscape Potential If score is: 3or4 = H ^ lor2 ~ M 0=1 Record the rating on the first page 0 3.0. Is the water quality improvement provided by the site valuable to society? D 3.1. Does the wetland discharge directly (i.e., within 1 mi) to a stream, river, lake, or marine water tljaUilin the 303(d) list? .'Yes-1J*>-0 » D 3.2. Is the wetland in a basin or sub-basin where an aquatic resource is on the 303(d) list? ^ Yes =d»o = 0 ! D 3.3. Has the site been identified in a watershed or local plan as important for maintaining water quaJity_(onswer YES if there is a TMDLfor the basin in which the unit is found)? (Yes=jj»ik> = 0 Total for D 3 Add the points in the boxes above Rating of Value If score is: 2-4 -H 1 = M 0 = L Record the rating on the first page Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 5 Wetland name or number. A-DEPRESSIONAL AND FLATS WETLANDS Hydrologic Functions - Indicators that the site functions to reduce flooding and stream degradation D 4.0. Does the site have the potential to reduce flooding and erosion? D 4.1. Characteristics of surface water outflows from the wetland: Wetland is a depression or flat depression with no surface water leaving it (no outlet) points = 4 Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outletpoinf^2] Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch points = 1 Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing points = 0 D 4.2. Deoth of storace durins wet periods: Estimate the heiaht ofoondina above the bottom of the outlet. For wetlands with no outtet, measure from the surface of permanent water or if dry, the deepest part. Marks of ponding are 3 ft or more above the surface or bottom of outlet points = 7 Marks of ponding between 2 ft to < 3 ft from surface or bottom of outlet points = 5 Marks are at least 0.5 ft to < 2 ft from surface or bottom of outlet tfoTnts^3 ^> The wetland is a "headwater" wetland paints = 3 Wetland is flat but has small depressions on the surface that trap water points = 1 Marks of ponding less than 0.5 ft (6 in) points = 0 3 D 4.3. Contribution of the wetland to storaae in the watershed: Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itself. The area of the basin is less than 10 times the area of the unit pqinls The area of the basin is 10 to 100 times the area of the unit (points =£/ The area of the basin is more than 100 times the area of the unit points = 0 Entire wetland is in the Flats class points = 5 Total for D 4 ^ Add the points in the boxes above Rating of Site Potential If score is: 12-16 = H S5-11 = M 0-5 = 1. Record the rating on the first page D 5.0. Does the landscape have the potential to support hydrologic functions of the site? D 5.1. Does the wetland receive stormwater discharges? Yes = lCNo = Qj? D5.2.ls >10% of the area within 150 ft of the wetland in land uses that generate excess runoff? Yes = 1 (j4p=j££<'** D 5.3. Is more than 25% of the contributing basin of the wetland covered with intensive human land uses (residential at >1 residence/ac, urban, commercial, agriculture, etc.)? Yes = 1 fNo=j£2** Total for D 5 Add the points in the boxes above o Rating of Landscape Potential If score is: 3 = H lor2 = M Record the rating on the first page D 6.0, Are the hydrologic functions provided by the site valuable to society? D 6.1. The unit is in a landscape that has flooding problems. Choose the description that best matches conditions around the wetland unit being rated. Do not add points. Choose the tjiahest score if mqre than one condition is met. The wetland captures surface water that would otherwise flow down-gradient into areas where flooding has damaged human or natural resources (e.g., houses or salmon redds): • Flooding occurs in a sub-basin that is immediately down-gradient of unit. points = 2 • Surface flooding problems are in a sub-basin farther down-gradient. points = 1 Flooding from groundwater is an issue in the sub-basin. !- POint:^,=^^> The existing or potential outflow from the wetland is so constrained by human or natural conditions that the water stored by the wetland cannot reach areas that flood. Explain why t points = 0 There are no problems with flooding downstream of the wetland. points = 0 D 6.2. Has the site been identified as important for flood storage or flood conveyance in a regional flood control plan? Yes=2 No = 0 Total for D 6 Add the points in the boxes above Ratingof Value If scoreis: 2-4 = H **1 = M 0 = L Record the rating on the first page Wedand Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 6 200377 of 628 Wetland name or number These questions apply to wetlands of all HGM classes. HABITAT FUNCTIONS - Indicators that site functions to provide important habitat H 1.0. Does the site have the potential to provide habitat? H 1.1. Structure of plant community: Indicators are Cowardin classes and strata within the Forested class. Check the Cowardin plant classes in the wetland. Up to 10 patches may be combined for each class to meet the threshold of% oc or more than 10% of the unit if it is smaller than 2.5 ac. Add die number of structures checked. Aquatic bed 4 structures or more: points = 4 Emergent 3 structures: points = 2 Sprifcshrub {areas where shrubs have > 30% cover) 2 structures: points = 1 fr^orested (areas where trees have > 30% cover) 1 structure: ^rfcjj^ If the unit has a Forested class, check if: The Forested class has 3 out of 5 strata (canopy, sub-canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the Forested polygon H 1.2. Hydroperiods Check the types of water regimes (hydroperiods) present within the wetland. The water regime has to cover more than 10% of the wetland or % ac to count (see text for descriptions of hydroperiods). Perasanently flooded or inundated 4 or more types present: points = 3 ^Seasonally flooded or inundated 3 types present: points = 2 Occasionally flooded or inundated 2 types present: points = 1 Saturated only 1 type pr^ntT points - (T^ Permanently flowing stream or river in, or adjacent to, the wetland «-«...-.«-..-••«-•-<-Seasonally flowing stream in, or adjacent to, the wetland take Fringe wetland 2 points Freshwater tidal wetland 2 points H 1.3. Richness of plant species Count the number of plant species in the wetland that cover at least 10 ft2. Different patches of the same species can be combined to meet the size threshold and you do not have to name the species. Do not include Eurasian milfoil, reed canarygrass, purple loosestrife, Canadian thistle If you counted: > 19 species points = 2 5 -19 species vpoinj^^l^ < 5 species points = 0 I H 1.4. Interspersion of habitats Decide from the diagrams below whether interspersion among Cowardin plants classes (described in H 1.1), or the classes and unvegetated areas (can include open water or mudflats) is high, moderate, low, or none. If you have four or more plant classes or three classes and open water, the rating is always high. o CE> <S><&> ( None = 0 pojnjj^ Low = 1 point Moderate = 2 points All three diagrams /yffe tafjA M\ ^HEL 1 1^ 'j in ,his row \ Wy V J ^t^^m&y are HIGH = 3points N. ^/ H S Wedand Rating System fof Western WA: 2014 Update Rating Form - Effective Januaiy 1,2015 13 Wetland name or number H 1.5. Special habitat features: Ched^ne habitat features that are present in the wetland. The number of checks is the number of points. ^ Large, downed, woody debris within the wetland (> 4 in diameter and 6 ft long). Standing snags (dbh > 4 in) within the wetland Undercut banks are present for at least 6.6 ft (2 m) and/or overhanging plants extends at least 3.3 ft (1 m) over a stream (or ditch) in, or contiguous with the wetland, for at least 33 ft (10 m) Stable steep banks of fine material that might be used by beaver or muskrat for denning (> 30 degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet weathered where wood is exposed) Atteast % ac of thin-stemmed persistent plants or woody branches are present in areas that are ^^Jermanentty or seasonally inundated (structures for egg-laying by amphibians) Invasive plants cover less than 25% of the wetland area in every stratum of plants [see H 1.1 for list of strata) *T3^ Total for H 1 ^? Add the points in the boxes above 3 Rating of Site Potential If score is: 15-18 =H 7-14= M ^0-6 = L Record the rating on the first page H 2.0. Does the landscape have the potential to support the habitat functions of the site? H 2.1. Accessible habitat (indude only habitat thatdirecdy abuts wetland unit). ^ Calculate: ^ % undisturbed habitat f®+ f(% moderate and low intensity land uses)/21 = ^ % If total accessible habitat is: > Vs (33.3%) of 1 km Polygon points = 3 20-33% of 1 km Polygon P°|0ts =.2 10-19% of 1 km Polygon v pojnte =JL^, < 10% of 1 km Polygon points » 0 ' \ H 2.2. Undisturbed habitat in 1 km Polygon around the wetland. m . „„ Calculate: % undisturbed habitat*** + RK moderate and tow intensity land uses)/21 * « -? : % Undisturbed habitat > 50% of Polygon points = 3 Undisturbed habitat 10-50% and in l-3patches point5.= 2i Undisturbed habitat 10-50% and > 3 patches K points = 1^ Undisturbed habitat < 10% of 1 km Polygon points = 0 ! H 2.3. Land use intensity in 1 km Polygon: If > 50% of 1 km Polygon is high intensity land use points = (- 2) £ 50% of 1 km Polygon is high intensity r points = 0'? Total for H 2 ^ Add the points in the boxes above Rating of Landscape Potential tf score is: 4-6 = H ^-3 * M < 1 = L Record the rating on the first page H 3.0. Is the habitat provided by the site valuable to society? H 3.1. Does the site provide habitat for species valued in laws, regulations, or policies? Choose only the highest score that applies to the wetland being rated. Site meets ANY of the following criteria: points = 2 — It has 3 or more priority habitats within 100 m (see next page} — It provides habitat for Threatened or Endangered species (any plant or animal on the state or federal lists) — it is mapped as a location for an individual WDFW priority species — It is a Wetland of High Conservation Value as determined by the Department of Natural Resources — It has been categorized as an important habitat site in a local or regional comprehensive plan, in a Shoreline Master Plan, or in a watershed plan Site has 1 or 2 priority habitats (listed on next page) within 100 m points = 1 Site does not meet anv of the criteria above ^ r, points = 0. ' ,.s* Rating of Value If score is: 2 = H 1 = M _£jO = L Record the rating on the first page Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 14 201378 of 628 Wetland name or number WDFW Priority Habitats Priority habitats listed by WDFW (see complete descriptions of WDFW priority habitats, and the counties in which they can be found, in: Washington Department of Fish and Wildlife. 2008. Priority Habitat and Species List. Olympia, Washington, 1^7 pp, http://wdfw.wa.gov/p.uhIj.cff^ or access the list from here: hUp;//yvrifWiWfl,soy/cpnserYaUon/ph.Vli.>t/3 Count how many of the following priority habitats are wfthin 330 ft (100 m) of the wetland unit: NOTE: This question is independent of the land use between the wetland unit and the priority habitat — Aspen Stands: Pure or mixed stands of aspen greater than 1 ac (0.4 ha). — Biodiversity Areas and Corridors: Areas of habitat that are relatively important to various species of native fish and wildlife {full descriptions in WDFWPHSreport). — Herbaceous Balds: Variable size patches of grass and forbs on shallow soils over bedrock. — Old-growth/Mature forests: Qld-firflwfo west of Cascade crest - Stands of at least 2 tree species, forming a multi-layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha} > 32 in (81 cm) dbh or > 200 years of age. Mature forests - Stands with average diameters exceeding 21 in (53 cm) dbh; crown cover may be less than 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth; 80-200 years old west of the Cascade crest — Oregon White Oak; Woodland stands of pure oak or oak/conifer associations where canopy coverage of the oak component is important [full descriptions In WDFW PHS report p. 158 - see web link above). — Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. — Westside Prairies: Herbaceous, non-forested plant communities that can either take the form of a dry prairie or a wet prairie {full descriptions in WDFW PHS report p. 161 - see web link above). — Instream: The combination of physical, biological, and chemical processes and conditions that interact to provide functional life history requirements for instream fish and wildlife resources. — Nearshore: Relatively undisturbed nearshorehabitats, These include Coastal Nearshore, Open Coast Nearshore, and Puget Sound Nearshore. (full descriptions of habitats and the definition of relatively undisturbed are in WDFW report -see web link on previous page). — Caves; A naturally occurring cavity, recess, void, or system of interconnected passages under the earth in soils, rock, ice, or other geological formations and is large enough to contain a human. — Cliffs: Greater than 25 ft (7.6 m) high and occurring below 5000 ft elevation. — Talus: Homogenous areas of rock rubble ranging in average size 0.5 - 6.5 ft (0.15 - 2.0 m), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. — Snags and Logs: Trees are considered snags if they are dead or dying and exhibit sufficient decay characteristics to enable cavity excavation/use by wildlife. Priority snags have a diameter at breast height of > 20 in (51 cm) in western Washington and are > 6.5 ft (2 m) in height Priority logs are > 12 in (30 cm) in diameter at the largest end, and > 20 ft (6 m) long. Note: All vegetated wetlands are by definition a priority habitat but are not included in this list because they are addressed elsewhere. Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 15 Wetland name or number CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Wetland Type Check off any criteria that apply to the wedand. Grcle the category when the appropriate criteria are met. Category SC 1.0. Estuarine wetlands Does the wetland meet the following criteria for Estuarine wetlands? — The dominant water regime is tidal, — Vegetated, and — With a salinity greater than 0.5 ppt Yes -Go to SC 1.1 <1$o= Not an estuarine wetland^ SC 1.1. Is the wetland within a National Wildlife Refuge, National Park, National c^"^^^^ Nnturiil ^r~r Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? Yes - Category 1 No - Go to SC 1.2 Cat 1 SC 1.2. Is the wetland unit at least 1 ac in size and meets at least two of the following three conditions? —The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than 10% cover of non-native plant species. (If non-native species are Spartkia, see page 25) —At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. —The wetland has at least two of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. Yes = Category 1 No = Category II Cat. 1 Cat II SC2.0. Wetlands of High Conservation Value (WHCV) SC 2.1. Has the WA Department of Natural Resources updated their website to include the list of Wetlands of High Conservation Value? Yes - Go to SC 2.2 'fi^Go^SXil* SC 2.2. Is the wetland listed on the WDNR database as a Wetland of High Conservation Value? Yes = Category 1 No = Not a WHCV SC 2.3. Is the wetland in a Section/Township/Range that contains a Natural Heritage wetland? httD://wwwl.dnr.wa.eov/nhD/refdesk/datasearchywnhDwetlands.Ddf ~ ^ Yes -Contact WNHP/WDIMR and go to SC 2.4 V.=$oi = Not a WHCV^ SC 2.4. Has WDNR identified the wetland within the S/T/R as a Wetland of High Conservation Value and listed it on their website? Yes = Category 1 No = Not a WHCV Cat I SC 3.0. Bogs Does the wetland (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below. If you answer YES you will still need to rate the wetland based on Its functions. SC 3.1. Does an area within the wetland unit have organic soil horizons, either peats or mucks, that compose 16 ,ip_ or more of the first 32 in of the soil profile? Yes - Go to SC 3.3\o - Go to SC 3.2\ SC 3.2. Does an area within the wetland unit have organic soils, either peats or mucks, that are lesTfflalflKlna^ep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on top of a Tafceoc^ pond? Yes-Go to SC 3.3 ^lo = !s noXa.bog-SC 3.3. Does an area with peats or mucks have more than 70% cover of mosses at ground level, AND atleast a 30% cover of plant species listed in Table 4? Yes = Is a Category 1 bog No - Go to SC 3.4 NOTE: If you are uncertain about the extent of mosses in the understory, you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16 in deep. If the pH is less than 5.0 and the plant species in Table 4 are present, the wetland is a bog. SC 3.4. Is an area with peats or mucks forested (> 30% cover) with Sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Engelmann spruce, or western white pine, AN D any of the species (or combination of species) listed in Table 4 provide more than 30% of the cover under the canopy? Yes = Is a Category f bog No = Is not a bog Cat 1 Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 16 202379 of 628 Wetland name or number SC 4.0. Forested Wetlands Does the wetland have at least 1 contiguous acre of forest that meets one of these criteria for the WA Department of Fish and Wildlife's forests as priority habitats? If you answer YES you will still need to rate the wetland based on Us functions, — Old-growth forests (west of Cascade crest): Stands of at least two tree species, forming a multi-layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 in (81 cm) or more. — Mature forests (west of the Cascade Crest): Stands where the largest trees are 80- 200 years old OR the species that make up the canopy have an average diameter (dbh) exceeding 21 in (53 cm): ~— Yes = Category 1 No = Not a forested wetland for th'nsecS^ Cat 1 SC 5.0. Wetlands In Coastal Lagoons ^» ,»• ^^^"^^ Does the wetland meet all of the following criteria of a wetland in a coastal lagoon? — The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks — The lagoon in which the wetland is located contains ponded water that is saline or brackish (> 0.5-pot) during most of the year in at least a portion of the lagoon (needs to be meesurednear the bottom) Yes -Go to SC 5.1 Uo= Not a wetland in a coastal lagoon SC 5.1. Does the wetland meet all of the following three conditions? ,,,VVJWa.,-»w,-^™..».~.,- - ""' — The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of aggressive, opportunistic plant species (see list of species on p. 100). — At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. —The wetland is larger than Vio ac (4350 ft2) Yes = Category I No = Category II Cat. 1 Cat II SC 6.0. Interdunal Wetlands Is the wetland west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? // you answer yes you wHI still need to rate the wetland based on Its habitat functions. In practical terms that means the following geographic areas: — Long Beach Peninsula: Lands west of SR 103 — Grayfand-Westport: Lands west of SR 105 . .,.^_^jK — Ocean Shores-Copalis: Lands west of SR 115 and SR 109 ^""^ ^ ^ Yes - Go to SC 6.1 No = hot an Interdunal wetland forrjjior^ SC 6.1. Is the wetland 1 ac or larger and scores an 8 or 9 for the habitat functions on the form (rates H,H,H or H,H,M for the three aspects of function)? Yes = Category 1 No - Go to SC 6.2 SC 6.2. Is the wetland 1 ac or larger, or is it in a mosaic of wetlands that is 1 ac or larger? Yes = Category II No-Go to SC 6.3 SC 6.3. Is the unit between 0.1 and 1 ac, or is it in a mosaic of wetlands that is between 0.1 and 1 ac? Yes = Category III No = Category IV Cat) Cat. 1) Cat. Ill Cat. IV Category of wetland based on Special Characteristics If you answered No for all types, enter "Not Applicable" on Summary Form Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1,2015 17 203380 of 628 204 381 of 628 205 382 of 628 206 383 of 628 207 Attachment E Declaration of Covenant for Privately Maintained Facilities 384 of 628 208 A Declaration of Covenant will be prepared during the FAC permit review. 385 of 628 209 Attachment F Downstream Quantitative Analysis 386 of 628 210 Ponding complaint due to neighbor regrading ravine to SR-18. Landslide hazard area catch basin with pipes flowing south, storm conveyance extends to ravine location basin/ridge line Downstream Drainage Map 387 of 628 211 Existing Conditions 388 of 628 18355.007.docx OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Basin: Green River Subbasin Name: Mill Creek Subbasin Number: Symbol Drainage Component Type, Name, and Size Drainage Component Description Slope Distance from site discharge Existing Problems Potential Problems Observations of field inspector, resource reviewer, or resident see map Type: sheet flow, swale, stream, channel, pipe, pond; Size: diameter, surface area drainage basin, vegetation, cover, depth, type of sensitive area, volume % ¼ ml = 1,320 ft. constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction, scouring, bank sloughing, sedimentation, incision, other erosion tributary area, likelihood of problem, overflow pathways, potential impacts A Roadside swale Recently cut trees, brush, bare ground 4 0-150 Cleared area could be prone to erosion until stabilized See photo B 12” Conc pipe Across S 329th 4 150-190 C 12” CPEP Pipe Across 51st Ave S 4.9 190-232 D 12” CMP Pipe 6.1 232-373 E 12” CMP Pipe 6.3 373-554 F 12” CMP Pipe West to 46th 6.25 554-601 G 12” CMP Pipe Across 46th 2.4 601-644 H 12” CMP Pipe 3.1 644-712 I 12” CMP Pipe 1.1 712-791 J 12” CMP Pipe 4.6 791-916 K 12” CMP Pipe 2.4 916-968 L 12” CMP Pipe 1.7 968-1024 M Ditch 1’ deep -0.34 1024-1100 Reverse slope See photo N 12” Conc Pipe 0.9 1100-1119 O Ditch 1:1 side slopes 1.85 1119-1153 See photo 212389 of 628 18355.007.docx P 12” CMP Pipe -0.7 1153-1163 Reverse slope Q 12” Conc Pipe 1.7 1163-1210 R 12” Conc Pipe -7.6 1210-1217 Reverse slope S Ditch Overgrown with ivy, 1’ deep, 2’ bottom width, 4:1 side slope 2.2 1217-1274 T 12” Conc Pipe -0.3 1274-1304 Reverse slope U Ditch 2’ deep, 2’-3’ bottom width, 1:1 road slope, 3:1 prop slope, ivy 0.9 1304-1426 V 12” Conc Pipe 0.28 1426-1466 W Ditch 2’-3’ deep, 2’ bottom width, 2:1 slopes 2.5 1466-1505 X 12” Conc Pipe 0.3 1505-1565 CB not found, drainage ditch from the north Y Ditch 2’ deep, ‘v’ ditch, 2:1 road slope, 3:1 prop slope, grass 0.95 1565-1595 Z 12” CPEP Pipe 3.3 1595-1615 AA Ditch 3’-5’ deep, 2’ bottom width, 2:1 to 1:1 slopes 5.4 1615-1670 Opens to low area where it meets the swale from the north BB 12” Conc Pipe 4.2 1670-1708 CC 12” Conc Pipe UNK 1708-1846 Discharges to ravine, very steep downstream from outlet 213390 of 628 214 Looking north from S 329th St 391 of 628 215 Ditch M 392 of 628 216 Ditch O 393 of 628 217 Ditch S 394 of 628 218 Ditch U 395 of 628 219 Ditch W 396 of 628 220 397 of 628 221 398 of 628 222 399 of 628 223 Existing Conditions 19.24 ac 1.31 ac 0.87 ac 2.25 ac 0.50 ac 1.42 ac 0.49 ac 0.53 ac 0.45 ac 0.43 ac 0.13 ac 0.92 ac 0.45 ac 1.97 ac 1.18 ac 2.20 ac 11.97 ac 0.11 ac 0.05 ac 0.26 ac 400 of 628 224ExistingConditions withproject25-yr flowsblue signifies flooding401 of 628 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis225Existing system withproject added25-yr stormConnectionto existingProposed Pond Discharge402 of 628 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis226Existing system withproject added25-yr storm403 of 628 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis227Existing system withproject added25-yr storm404 of 628 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis228Existing system withproject added25-yr stormDischarge location405 of 628 229ExistingConditions withproject100-yr flowsblue signifies floodingred is a surchargedpipe406 of 628 Autodesk® Storm and Sanitary Analysis 2016 - Version 12.0.42 (Build 0) ----------------------------------------------------------------------------------------- ******************* Project Description ******************* File Name ................. 18355-ds-ex with project.SPF **************** Analysis Options **************** Flow Units ................ cfs Subbasin Hydrograph Method. Santa Barbara UH Time of Concentration...... SCS TR-55 Link Routing Method ....... Hydrodynamic Storage Node Exfiltration.. None Starting Date ............. MAR-05-2019 00:00:00 Ending Date ............... MAR-06-2019 00:00:00 Report Time Step .......... 00:00:10 ************* Element Count ************* Number of rain gages ...... 1 Number of subbasins ....... 20 Number of nodes ........... 40 Number of links ........... 39 **************** Raingage Summary **************** Gage Data Data Recording ID Source Type Interval min ------------------------------------------------------------ Rain Gage-01 TS-01 CUMULATIVE 15.00 **************** Subbasin Summary **************** Subbasin Total Imperv. Raingage Area Area ID acres % ---------------------------------------------------- BasinstoPond 19.24 5.00 Rain Gage-01 Sub-292 0.45 45.00 Rain Gage-01 Sub-293 0.53 58.00 Rain Gage-01 Sub-294 0.49 60.00 Rain Gage-01 Sub-295 2.25 50.00 Rain Gage-01 Sub-300 1.42 40.00 Rain Gage-01 Sub-301 0.50 50.00 Rain Gage-01 Sub-303 0.87 30.00 Rain Gage-01 Sub-304 1.31 40.00 Rain Gage-01 Sub-307 0.43 58.00 Rain Gage-01 Sub-309 0.13 38.00 Rain Gage-01 Sub-310 0.92 55.00 Rain Gage-01 Sub-313 0.45 57.00 Rain Gage-01 Sub-315 1.97 38.00 Rain Gage-01 Sub-317 1.18 63.00 Rain Gage-01 Sub-319 2.20 45.00 Rain Gage-01 Sub-323 11.97 25.00 Rain Gage-01 Sub-324 0.11 75.00 Rain Gage-01 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 230 407 of 628 Sub-327 0.05 75.00 Rain Gage-01 Sub-328 0.26 75.00 Rain Gage-01 ************ Node Summary ************ Node Element Invert Maximum Ponded External ID Type Elevation Elev. Area Inflow ft ft ft² ------------------------------------------------------------------------------ 305-00320 JUNCTION 337.35 339.35 0.00 804-00293 JUNCTION 349.70 352.11 0.00 804-00294 JUNCTION 350.73 353.25 0.00 804-00295 JUNCTION 352.69 354.83 0.00 804-00299 JUNCTION 357.13 359.24 0.00 804-00300 JUNCTION 357.36 359.55 0.00 804-00301 JUNCTION 368.84 371.49 0.00 804-00302 JUNCTION 377.48 379.84 0.00 805-00292 JUNCTION 343.98 345.64 0.00 805-00303 JUNCTION 379.62 382.08 0.00 805-00305 JUNCTION 343.33 345.30 0.00 805-00306 JUNCTION 342.54 344.50 0.00 805-00307 JUNCTION 343.31 344.81 0.00 805-00308 JUNCTION 342.06 344.20 0.00 805-00309 JUNCTION 341.40 343.77 0.00 805-00310 JUNCTION 341.44 343.57 0.00 805-00311 JUNCTION 340.71 343.15 0.00 805-00312 JUNCTION 340.66 342.90 0.00 805-00313 JUNCTION 339.85 342.00 0.00 805-00314 JUNCTION 340.06 342.06 0.00 805-00315 JUNCTION 338.92 340.92 0.00 805-00316 JUNCTION 338.70 340.70 0.00 805-00317 JUNCTION 338.06 340.20 0.00 805-00318 JUNCTION 338.07 339.90 0.00 805-00319 JUNCTION 337.24 339.90 0.00 805-00321 JUNCTION 337.18 339.18 0.00 805-00322 JUNCTION 336.63 339.63 0.00 805-00323 JUNCTION 333.69 338.00 0.00 805-00324 JUNCTION 331.88 337.00 0.00 805-00325 JUNCTION 333.88 336.90 0.00 805-00326 JUNCTION 335.32 338.50 0.00 805-00327 JUNCTION 337.52 339.52 0.00 805-00328 JUNCTION 340.85 342.90 0.00 CB#19 JUNCTION 387.00 395.41 0.00 CB#20 JUNCTION 387.75 416.10 0.00 CB#21 JUNCTION 388.50 407.42 0.00 CB#22 JUNCTION 389.25 396.00 0.00 CB#23 JUNCTION 390.00 396.00 0.00 Jun-06 JUNCTION 382.57 384.51 0.00 805-00396 OUTFALL 330.00 331.00 0.00 ************ Link Summary ************ Link From Node To Node Element Length Slope Manning's ID Type ft % Roughness -------------------------------------------------------------------------------------------- Link-01 805-00328 805-00327 CONDUIT 68.3 4.7584 0.0120 Link-02 805-00327 805-00324 CONDUIT 144.8 2.4865 0.0120 Link-03 805-00326 805-00325 CONDUIT 22.6 6.3717 0.0150 Link-04 805-00325 805-00323 CHANNEL 22.5 0.8444 0.0320 Link-05 805-00323 805-00324 CONDUIT 38.3 4.7320 0.0120 Link-06 805-00324 805-00396 CONDUIT 139.0 1.3740 0.0120 Link-12 Jun-06 805-00303 CONDUIT 45.1 6.5410 0.0120 Link-13 805-00303 804-00302 CONDUIT 38.9 5.5527 0.0120 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 231 408 of 628 Link-14 804-00302 804-00301 CONDUIT 141.9 6.0606 0.0240 Link-15 804-00301 804-00300 CONDUIT 182.0 6.2582 0.0240 Link-16 804-00300 804-00299 CONDUIT 47.3 0.4863 0.0240 Link-17 804-00299 804-00295 CONDUIT 43.8 9.1096 0.0240 Link-18 804-00295 804-00294 CONDUIT 68.3 2.8697 0.0240 Link-19 804-00294 804-00293 CONDUIT 79.5 1.2075 0.0240 Link-20 804-00293 805-00292 CONDUIT 125.1 4.5484 0.0240 Link-21 805-00292 805-00305 CONDUIT 53.5 1.0093 0.0240 Link-22 805-00307 805-00306 CHANNEL 73.1 1.0534 0.0320 Link-23 805-00305 805-00306 CONDUIT 54.2 1.7159 0.0240 Link-24 805-00307 805-00308 CONDUIT 18.8 6.6489 0.0120 Link-25 805-00308 805-00309 CHANNEL 29.8 2.2148 0.0320 Link-26 805-00310 805-00309 CONDUIT 10.3 0.3883 0.0240 Link-27 805-00310 805-00311 CONDUIT 47.2 1.8432 0.0120 Link-28 805-00311 805-00312 CONDUIT 7.4 0.6757 0.0120 Link-29 805-00312 805-00313 CHANNEL 56.7 1.4286 0.0320 Link-30 805-00314 805-00313 CONDUIT 28.8 0.7292 0.0120 Link-31 805-00314 805-00315 CHANNEL 122.1 0.9337 0.0500 Link-32 805-00315 805-00316 CONDUIT 38.1 0.5774 0.0120 Link-33 805-00316 805-00317 CHANNEL 39.4 1.6244 0.0320 Link-34 805-00317 805-00319 CONDUIT 31.6 2.4684 0.0120 Link-35 805-00318 805-00319 CONDUIT 8.5 9.2941 0.0120 Link-36 305-00320 805-00319 CONDUIT 29.3 0.3754 0.0120 Link-37 305-00320 805-00321 CHANNEL 30.4 0.5592 0.0320 Link-38 805-00321 805-00322 CONDUIT 17.6 3.1250 0.0120 Link-39 805-00322 805-00323 CHANNEL 54.6 5.3846 0.0320 Link-40 CB#23 CB#22 CONDUIT 136.0 0.5515 0.0120 Link-41 CB#22 CB#21 CONDUIT 250.0 0.3000 0.0120 Link-42 CB#21 CB#20 CONDUIT 250.0 0.3000 0.0120 Link-43 CB#20 CB#19 CONDUIT 187.2 0.4006 0.0120 Link-45 CB#19 804-00302 CONDUIT 240.4 3.9604 0.0150 ********************* Cross Section Summary ********************* Link Shape Depth/ Width No. of Cross Full Flow Design ID Diameter Barrels Sectional Hydraulic Flow Area Radius Capacity ft ft ft² ft cfs ------------------------------------------------------------------------------------------------- --------- Link-01 CIRCULAR 1.00 1.00 1 0.79 0.25 8.42 Link-02 CIRCULAR 1.00 1.00 1 0.79 0.25 6.09 Link-03 CIRCULAR 1.00 1.00 1 0.79 0.25 7.79 Link-04 TRAPEZOIDAL 3.00 10.90 1 17.85 1.40 95.53 Link-05 CIRCULAR 1.00 1.00 1 0.79 0.25 8.40 Link-06 CIRCULAR 1.00 1.00 1 0.79 0.25 4.52 Link-12 CIRCULAR 1.00 1.00 1 0.79 0.25 9.87 Link-13 CIRCULAR 1.00 1.00 1 0.79 0.25 9.10 Link-14 CIRCULAR 1.00 1.00 1 0.79 0.25 4.75 Link-15 CIRCULAR 1.00 1.00 1 0.79 0.25 4.83 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 232 409 of 628 Link-16 CIRCULAR 1.00 1.00 1 0.79 0.25 1.35 Link-17 CIRCULAR 1.00 1.00 1 0.79 0.25 5.82 Link-18 CIRCULAR 1.00 1.00 1 0.79 0.25 3.27 Link-19 CIRCULAR 1.00 1.00 1 0.79 0.25 2.12 Link-20 CIRCULAR 1.00 1.00 1 0.79 0.25 4.12 Link-21 CIRCULAR 1.00 1.00 1 0.79 0.25 1.94 Link-22 TRAPEZOIDAL 1.50 8.50 1 7.13 0.78 28.85 Link-23 CIRCULAR 1.00 1.00 1 0.79 0.25 2.53 Link-24 CIRCULAR 1.00 1.00 1 0.79 0.25 9.95 Link-25 TRAPEZOIDAL 2.00 8.50 1 9.00 0.95 60.03 Link-26 CIRCULAR 1.00 1.00 1 0.79 0.25 1.20 Link-27 CIRCULAR 1.00 1.00 1 0.79 0.25 5.24 Link-28 CIRCULAR 1.00 1.00 1 0.79 0.25 3.17 Link-29 TRAPEZOIDAL 1.90 10.36 1 11.74 1.05 67.33 Link-30 CIRCULAR 1.00 1.00 1 0.79 0.25 3.30 Link-31 TRAPEZOIDAL 2.00 9.90 1 11.80 1.08 35.57 Link-32 CIRCULAR 1.00 1.00 1 0.79 0.25 2.93 Link-33 TRAPEZOIDAL 2.00 7.40 1 9.40 1.07 58.37 Link-34 CIRCULAR 1.00 1.00 1 0.79 0.25 6.06 Link-35 CIRCULAR 1.00 1.00 1 0.79 0.25 11.77 Link-36 CIRCULAR 1.00 1.00 1 0.79 0.25 2.36 Link-37 TRAPEZOIDAL 2.00 8.30 1 8.40 0.90 27.20 Link-38 CIRCULAR 1.00 1.00 1 0.79 0.25 6.82 Link-39 TRAPEZOIDAL 3.00 10.90 1 17.85 1.40 241.22 Link-40 CIRCULAR 1.00 1.00 1 0.79 0.25 2.87 Link-41 CIRCULAR 1.00 1.00 1 0.79 0.25 2.11 Link-42 CIRCULAR 1.00 1.00 1 0.79 0.25 2.11 Link-43 CIRCULAR 1.00 1.00 1 0.79 0.25 2.44 Link-45 CIRCULAR 1.50 1.50 1 1.77 0.38 18.12 ************************** Volume Depth Runoff Quantity Continuity acre-ft inches ************************** --------- ------- Total Precipitation ...... 15.495 3.981 Surface Runoff ........... 7.565 1.944 Continuity Error (%) ..... -0.000 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 233 410 of 628 ************************** Volume Volume Flow Routing Continuity acre-ft Mgallons ************************** --------- --------- External Inflow .......... 0.000 0.000 External Outflow ......... 6.672 2.174 Initial Stored Volume .... 0.000 0.000 Final Stored Volume ...... 0.038 0.012 Continuity Error (%) ..... 0.001 ****************************************** Composite Curve Number Computations Report ****************************************** ------------------------ Subbasin BasinstoPond ------------------------ Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 19.24 71.40 ------------------- Subbasin Sub-292 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.45 85.35 ------------------- Subbasin Sub-293 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.53 88.34 ------------------- Subbasin Sub-294 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.49 88.80 ------------------- Subbasin Sub-295 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 2.25 84.00 ------------------- Subbasin Sub-300 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 1.42 84.20 ------------------- Subbasin Sub-301 ------------------- Area Soil Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 234 411 of 628 Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.50 86.50 ------------------- Subbasin Sub-303 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.87 81.90 ------------------- Subbasin Sub-304 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 1.31 84.20 ------------------- Subbasin Sub-307 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.43 88.34 ------------------- Subbasin Sub-309 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.13 83.74 ------------------- Subbasin Sub-310 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.92 87.65 ------------------- Subbasin Sub-313 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.45 88.11 ------------------- Subbasin Sub-315 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 1.97 83.74 ------------------- Subbasin Sub-317 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 1.18 89.49 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 235 412 of 628 ------------------- Subbasin Sub-319 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 2.20 85.35 ------------------- Subbasin Sub-323 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 11.97 78.50 ------------------- Subbasin Sub-324 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.11 94.75 ------------------- Subbasin Sub-327 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.05 94.75 ------------------- Subbasin Sub-328 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.26 94.75 ************************************** Runoff Coefficient Computations Report ************************************** ------------------------ Subbasin BasinstoPond ------------------------ Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 19.24 - 0.72 Composite Area & Weighted Runoff Coeff. 19.24 0.72 ------------------- Subbasin Sub-292 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.45 - 0.72 Composite Area & Weighted Runoff Coeff. 0.45 0.72 ------------------- Subbasin Sub-293 ------------------- Area Soil Runoff Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 236 413 of 628 Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.53 - 0.72 Composite Area & Weighted Runoff Coeff. 0.53 0.72 ------------------- Subbasin Sub-294 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.49 - 0.72 Composite Area & Weighted Runoff Coeff. 0.49 0.72 ------------------- Subbasin Sub-295 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 2.25 - 0.72 Composite Area & Weighted Runoff Coeff. 2.25 0.72 ------------------- Subbasin Sub-300 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 1.42 - 0.72 Composite Area & Weighted Runoff Coeff. 1.42 0.72 ------------------- Subbasin Sub-301 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.50 - 0.72 Composite Area & Weighted Runoff Coeff. 0.50 0.72 ------------------- Subbasin Sub-303 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.87 - 0.72 Composite Area & Weighted Runoff Coeff. 0.87 0.72 ------------------- Subbasin Sub-304 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 1.31 - 0.72 Composite Area & Weighted Runoff Coeff. 1.31 0.72 ------------------- Subbasin Sub-307 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.43 - 0.72 Composite Area & Weighted Runoff Coeff. 0.43 0.72 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 237 414 of 628 ------------------- Subbasin Sub-309 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.13 - 0.72 Composite Area & Weighted Runoff Coeff. 0.13 0.72 ------------------- Subbasin Sub-310 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.92 - 0.72 Composite Area & Weighted Runoff Coeff. 0.92 0.72 ------------------- Subbasin Sub-313 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.45 - 0.72 Composite Area & Weighted Runoff Coeff. 0.45 0.72 ------------------- Subbasin Sub-315 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 1.97 - 0.72 Composite Area & Weighted Runoff Coeff. 1.97 0.72 ------------------- Subbasin Sub-317 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 1.18 - 0.72 Composite Area & Weighted Runoff Coeff. 1.18 0.72 ------------------- Subbasin Sub-319 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 2.20 - 0.72 Composite Area & Weighted Runoff Coeff. 2.20 0.72 ------------------- Subbasin Sub-323 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 11.97 - 0.72 Composite Area & Weighted Runoff Coeff. 11.97 0.72 ------------------- Subbasin Sub-324 ------------------- Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 238 415 of 628 Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.11 - 0.72 Composite Area & Weighted Runoff Coeff. 0.11 0.72 ------------------- Subbasin Sub-327 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.05 - 0.72 Composite Area & Weighted Runoff Coeff. 0.05 0.72 ------------------- Subbasin Sub-328 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.26 - 0.72 Composite Area & Weighted Runoff Coeff. 0.26 0.72 *************************************************** SCS TR-55 Time of Concentration Computations Report *************************************************** Sheet Flow Equation ------------------- Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where: Tc = Time of Concentration (hrs) n = Manning's Roughness Lf = Flow Length (ft) P = 2 yr, 24 hr Rainfall (inches) Sf = Slope (ft/ft) Shallow Concentrated Flow Equation ---------------------------------- V = 16.1345 * (Sf^0.5) (unpaved surface) V = 20.3282 * (Sf^0.5) (paved surface) V = 15.0 * (Sf^0.5) (grassed waterway surface) V = 10.0 * (Sf^0.5) (nearly bare & untilled surface) V = 9.0 * (Sf^0.5) (cultivated straight rows surface) V = 7.0 * (Sf^0.5) (short grass pasture surface) V = 5.0 * (Sf^0.5) (woodland surface) V = 2.5 * (Sf^0.5) (forest w/heavy litter surface) Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) Channel Flow Equation --------------------- V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n R = Aq / Wp Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 239 416 of 628 Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) R = Hydraulic Radius (ft) Aq = Flow Area (ft²) Wp = Wetted Perimeter (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) n = Manning's Roughness ------------------------ Subbasin BasinstoPond ------------------------ Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.80 0.00 0.00 Flow Length (ft): 200.00 0.00 0.00 Slope (%): 16.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.09 0.00 0.00 Computed Flow Time (minutes): 35.84 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 1385.00 0.00 0.00 Slope (%): 7.00 0.00 0.00 Surface Type: Woodland Unpaved Unpaved Velocity (ft/sec): 1.32 0.00 0.00 Computed Flow Time (minutes): 17.49 0.00 0.00 Channel Flow Computations ------------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.10 0.00 0.00 Flow Length (ft): 400.00 0.00 0.00 Channel Slope (%): 7.00 0.00 0.00 Cross Section Area (ft²): 7.50 0.00 0.00 Wetted Perimeter (ft): 30.00 0.00 0.00 Velocity (ft/sec): 1.56 0.00 0.00 Computed Flow Time (minutes): 4.26 0.00 0.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 240 417 of 628 ================================================================================================ Total TOC (minutes): 57.59 ================================================================================================ ------------------- Subbasin Sub-292 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 200.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.13 0.00 0.00 Computed Flow Time (minutes): 24.84 0.00 0.00 ================================================================================================ Total TOC (minutes): 24.84 ================================================================================================ ------------------- Subbasin Sub-293 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 280.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.14 0.00 0.00 Computed Flow Time (minutes): 32.52 0.00 0.00 ================================================================================================ Total TOC (minutes): 32.52 ================================================================================================ ------------------- Subbasin Sub-294 ------------------- Sheet Flow Computations ----------------------- Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 241 418 of 628 Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 ================================================================================================ Total TOC (minutes): 34.36 ================================================================================================ ------------------- Subbasin Sub-295 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 450.00 0.00 0.00 Slope (%): 4.00 0.00 0.00 Surface Type: Paved Unpaved Unpaved Velocity (ft/sec): 4.07 0.00 0.00 Computed Flow Time (minutes): 1.84 0.00 0.00 ================================================================================================ Total TOC (minutes): 36.20 ================================================================================================ ------------------- Subbasin Sub-300 ------------------- Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 242 419 of 628 Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 11.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 33.08 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 150.00 0.00 0.00 Slope (%): 6.00 0.00 0.00 Surface Type: Paved Unpaved Unpaved Velocity (ft/sec): 4.98 0.00 0.00 Computed Flow Time (minutes): 0.50 0.00 0.00 ================================================================================================ Total TOC (minutes): 33.58 ================================================================================================ ------------------- Subbasin Sub-301 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 250.00 0.00 0.00 Slope (%): 12.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 27.61 0.00 0.00 ================================================================================================ Total TOC (minutes): 27.61 ================================================================================================ ------------------- Subbasin Sub-303 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 243 420 of 628 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 200.00 0.00 0.00 Slope (%): 5.70 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.11 0.00 0.00 Computed Flow Time (minutes): 31.11 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 250.00 0.00 0.00 Slope (%): 12.00 0.00 0.00 Surface Type: Paved Unpaved Unpaved Velocity (ft/sec): 7.04 0.00 0.00 Computed Flow Time (minutes): 0.59 0.00 0.00 ================================================================================================ Total TOC (minutes): 31.70 ================================================================================================ ------------------- Subbasin Sub-304 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.50 0.00 0.00 Flow Length (ft): 250.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.12 0.00 0.00 Computed Flow Time (minutes): 35.50 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 500.00 0.00 0.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 244 421 of 628 Slope (%): 4.00 0.00 0.00 Surface Type: Paved Unpaved Unpaved Velocity (ft/sec): 4.07 0.00 0.00 Computed Flow Time (minutes): 2.05 0.00 0.00 ================================================================================================ Total TOC (minutes): 37.55 ================================================================================================ ------------------- Subbasin Sub-307 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 200.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.13 0.00 0.00 Computed Flow Time (minutes): 24.84 0.00 0.00 ================================================================================================ Total TOC (minutes): 24.84 ================================================================================================ ------------------- Subbasin Sub-309 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 150.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.13 0.00 0.00 Computed Flow Time (minutes): 19.74 0.00 0.00 ================================================================================================ Total TOC (minutes): 19.74 ================================================================================================ Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 245 422 of 628 ------------------- Subbasin Sub-310 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 250.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 Surface Type: Grass pasture Unpaved Unpaved Velocity (ft/sec): 2.21 0.00 0.00 Computed Flow Time (minutes): 1.89 0.00 0.00 ================================================================================================ Total TOC (minutes): 36.25 ================================================================================================ ------------------- Subbasin Sub-313 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 246 423 of 628 Subarea A Subarea B Subarea C Flow Length (ft): 100.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 Surface Type: Grass pasture Unpaved Unpaved Velocity (ft/sec): 2.21 0.00 0.00 Computed Flow Time (minutes): 0.75 0.00 0.00 ================================================================================================ Total TOC (minutes): 35.12 ================================================================================================ ------------------- Subbasin Sub-315 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 250.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 Surface Type: Grass pasture Unpaved Unpaved Velocity (ft/sec): 2.21 0.00 0.00 Computed Flow Time (minutes): 1.89 0.00 0.00 ================================================================================================ Total TOC (minutes): 36.25 ================================================================================================ ------------------- Subbasin Sub-317 ------------------- Sheet Flow Computations ----------------------- Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 247 424 of 628 Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 220.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 Surface Type: Grass pasture Unpaved Unpaved Velocity (ft/sec): 2.21 0.00 0.00 Computed Flow Time (minutes): 1.66 0.00 0.00 ================================================================================================ Total TOC (minutes): 36.02 ================================================================================================ ------------------- Subbasin Sub-319 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 7.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.13 0.00 0.00 Computed Flow Time (minutes): 39.63 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 350.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 Surface Type: Grassed waterway Unpaved Unpaved Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 248 425 of 628 Velocity (ft/sec): 4.74 0.00 0.00 Computed Flow Time (minutes): 1.23 0.00 0.00 Channel Flow Computations ------------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.01 0.00 0.00 Flow Length (ft): 250.00 0.00 0.00 Channel Slope (%): 1.00 0.00 0.00 Cross Section Area (ft²): 0.79 0.00 0.00 Wetted Perimeter (ft): 3.14 0.00 0.00 Velocity (ft/sec): 4.95 0.00 0.00 Computed Flow Time (minutes): 0.84 0.00 0.00 ================================================================================================ Total TOC (minutes): 41.70 ================================================================================================ ------------------- Subbasin Sub-323 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 8.50 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.14 0.00 0.00 Computed Flow Time (minutes): 36.67 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 700.00 0.00 0.00 Slope (%): 9.00 0.00 0.00 Surface Type: Woodland Unpaved Unpaved Velocity (ft/sec): 1.50 0.00 0.00 Computed Flow Time (minutes): 7.78 0.00 0.00 ================================================================================================ Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 249 426 of 628 Total TOC (minutes): 44.45 ================================================================================================ ------------------- Subbasin Sub-324 ------------------- User-Defined TOC override (minutes): 6.30 ------------------- Subbasin Sub-327 ------------------- User-Defined TOC override (minutes): 6.30 ------------------- Subbasin Sub-328 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.01 0.00 0.00 Flow Length (ft): 380.00 0.00 0.00 Slope (%): 1.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.84 0.00 0.00 Computed Flow Time (minutes): 7.54 0.00 0.00 ================================================================================================ Total TOC (minutes): 7.54 ================================================================================================ *********************** Subbasin Runoff Summary *********************** -------------------------------------------------------------------------- Subbasin Total Total Peak Weighted Time of ID Precip Runoff Runoff Curve Concentration in in cfs Number days hh:mm:ss -------------------------------------------------------------------------- BasinstoPond 3.98 1.39 2.67 71.400 0 00:57:35 Sub-292 3.98 2.57 0.20 85.350 0 00:24:50 Sub-293 3.98 2.84 0.25 88.340 0 00:32:31 Sub-294 3.98 2.88 0.23 88.800 0 00:34:21 Sub-295 3.98 2.50 0.86 84.000 0 00:36:12 Sub-300 3.98 2.46 0.56 84.200 0 00:33:34 Sub-301 3.98 2.68 0.23 86.500 0 00:27:36 Sub-303 3.98 2.25 0.31 81.900 0 00:31:42 Sub-304 3.98 2.46 0.49 84.200 0 00:37:33 Sub-307 3.98 2.85 0.22 88.340 0 00:24:50 Sub-309 3.98 2.43 0.06 83.740 0 00:19:44 Sub-310 3.98 2.77 0.40 87.650 0 00:36:15 Sub-313 3.98 2.81 0.21 88.110 0 00:35:07 Sub-315 3.98 2.42 0.73 83.740 0 00:36:15 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 250 427 of 628 Sub-317 3.98 2.94 0.56 89.490 0 00:36:01 Sub-319 3.98 2.55 0.83 85.350 0 00:41:42 Sub-323 3.98 1.98 3.14 78.500 0 00:44:27 Sub-324 3.98 3.42 0.09 94.750 0 00:06:18 Sub-327 3.98 3.42 0.04 94.750 0 00:06:18 Sub-328 3.98 3.42 0.21 94.750 0 00:07:32 -------------------------------------------------------------------------- ****************** Node Depth Summary ****************** ----------------------------------------------------------------------------------------- Node Average Maximum Maximum Time of Max Total Total Retention ID Depth Depth HGL Occurrence Flooded Time Time Attained Attained Attained Volume Flooded ft ft ft days hh:mm acre-in minutes hh:mm:ss ----------------------------------------------------------------------------------------- 305-00320 0.85 1.11 338.46 0 08:16 0 0 0:00:00 804-00293 0.49 0.70 350.40 0 08:15 0 0 0:00:00 804-00294 1.07 2.26 352.99 0 08:15 0 0 0:00:00 804-00295 0.79 2.14 354.83 0 07:52 1.69 165 0:00:00 804-00299 0.38 0.54 357.67 0 08:05 0 0 0:00:00 804-00300 1.10 2.19 359.55 0 08:01 0.96 105 0:00:00 804-00301 0.38 0.64 369.48 0 08:30 0 0 0:00:00 804-00302 0.38 0.65 378.13 0 08:31 0 0 0:00:00 805-00292 1.23 1.66 345.64 0 07:41 4.85 502 0:00:00 805-00303 0.21 0.30 379.92 0 08:15 0 0 0:00:00 805-00305 1.12 1.43 344.76 0 08:15 0 0 0:00:00 805-00306 1.23 1.32 343.86 0 08:15 0 0 0:00:00 805-00307 0.36 0.45 343.76 0 08:15 0 0 0:00:00 805-00308 0.48 0.63 342.69 0 08:16 0 0 0:00:00 805-00309 1.02 1.26 342.66 0 08:16 0 0 0:00:00 805-00310 0.68 0.86 342.30 0 08:17 0 0 0:00:00 805-00311 0.69 1.06 341.77 0 08:21 0 0 0:00:00 805-00312 0.41 0.75 341.41 0 08:22 0 0 0:00:00 805-00313 1.15 1.55 341.40 0 08:22 0 0 0:00:00 805-00314 0.51 0.89 340.95 0 08:20 0 0 0:00:00 805-00315 0.83 2.00 340.92 0 08:20 0.01 11 0:00:00 805-00316 0.48 1.51 340.21 0 08:12 0 0 0:00:00 805-00317 0.90 2.14 340.20 0 08:11 0.15 40 0:00:00 805-00318 0.56 1.43 339.50 0 08:15 0 0 0:00:00 805-00319 1.36 2.24 339.48 0 08:15 0 0 0:00:00 805-00321 0.65 1.13 338.31 0 08:16 0 0 0:00:00 805-00322 0.38 0.51 337.14 0 08:16 0 0 0:00:00 805-00323 0.99 3.23 336.92 0 07:59 0 0 0:00:00 805-00324 1.30 3.40 335.28 0 07:59 0 0 0:00:00 805-00325 0.85 3.02 336.90 0 07:59 2.54 115 0:00:00 805-00326 0.46 2.06 337.38 0 08:15 0 0 0:00:00 805-00327 0.06 0.14 337.66 0 08:00 0 0 0:00:00 805-00328 0.05 0.11 340.96 0 08:00 0 0 0:00:00 CB#19 0.26 0.39 387.39 0 08:45 0 0 0:00:00 CB#20 0.56 1.18 388.93 0 08:45 0 0 0:00:00 CB#21 0.64 1.80 390.30 0 08:45 0 0 0:00:00 CB#22 0.68 2.78 392.03 0 08:11 0 0 0:00:00 CB#23 0.59 2.83 392.83 0 08:11 0 0 0:00:00 Jun-06 0.08 0.15 382.72 0 08:15 0 0 0:00:00 805-00396 0.73 1.00 331.00 0 07:39 0 0 0:00:00 ***************** Node Flow Summary ***************** ------------------------------------------------------------------------------------ Node Element Maximum Peak Time of Maximum Time of Peak Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 251 428 of 628 ID Type Lateral Inflow Peak Inflow Flooding Flooding Inflow Occurrence Overflow Occurrence cfs cfs days hh:mm cfs days hh:mm ------------------------------------------------------------------------------------ 305-00320 JUNCTION 0.00 4.77 0 08:15 0.00 804-00293 JUNCTION 0.25 3.44 0 08:15 0.00 804-00294 JUNCTION 0.23 3.20 0 08:15 0.00 804-00295 JUNCTION 0.86 4.00 0 08:15 1.04 0 08:15 804-00299 JUNCTION 0.00 3.14 0 09:15 0.00 804-00300 JUNCTION 0.56 4.10 0 08:29 0.95 0 08:29 804-00301 JUNCTION 0.23 3.59 0 08:30 0.00 804-00302 JUNCTION 0.00 3.40 0 08:30 0.00 805-00292 JUNCTION 0.20 3.65 0 08:15 1.36 0 08:15 805-00303 JUNCTION 0.31 0.80 0 08:15 0.00 805-00305 JUNCTION 0.00 2.30 0 07:41 0.00 805-00306 JUNCTION 0.00 2.30 0 07:41 0.00 805-00307 JUNCTION 0.22 2.50 0 08:15 0.00 805-00308 JUNCTION 0.00 2.50 0 08:15 0.00 805-00309 JUNCTION 0.06 2.56 0 08:15 0.00 805-00310 JUNCTION 0.40 2.96 0 08:15 0.00 805-00311 JUNCTION 0.00 2.96 0 08:15 0.00 805-00312 JUNCTION 0.00 2.96 0 08:15 0.00 805-00313 JUNCTION 0.21 3.14 0 08:16 0.00 805-00314 JUNCTION 0.00 3.13 0 08:22 0.00 805-00315 JUNCTION 0.73 3.85 0 08:21 0.09 0 08:21 805-00316 JUNCTION 0.00 3.75 0 08:20 0.00 805-00317 JUNCTION 0.56 4.29 0 08:20 0.35 0 08:20 805-00318 JUNCTION 0.83 0.83 0 08:15 0.00 805-00319 JUNCTION 0.00 4.77 0 08:15 0.00 805-00321 JUNCTION 0.00 4.77 0 08:15 0.00 805-00322 JUNCTION 0.00 4.76 0 08:16 0.00 805-00323 JUNCTION 0.00 6.54 0 07:58 0.00 805-00324 JUNCTION 0.09 6.04 0 07:59 0.00 805-00325 JUNCTION 0.00 3.14 0 08:15 2.19 0 08:15 805-00326 JUNCTION 3.14 3.14 0 08:15 0.00 805-00327 JUNCTION 0.04 0.26 0 08:00 0.00 805-00328 JUNCTION 0.21 0.21 0 08:00 0.00 CB#19 JUNCTION 0.00 2.67 0 08:45 0.00 CB#20 JUNCTION 0.00 2.67 0 08:45 0.00 CB#21 JUNCTION 0.00 2.67 0 08:45 0.00 CB#22 JUNCTION 0.00 2.67 0 08:45 0.00 CB#23 JUNCTION 2.67 2.67 0 08:45 0.00 Jun-06 JUNCTION 0.49 0.49 0 08:15 0.00 805-00396 OUTFALL 0.00 6.00 0 08:00 0.00 *********************** Outfall Loading Summary *********************** ----------------------------------------------- Outfall Node ID Flow Average Peak Frequency Flow Inflow (%) cfs cfs ----------------------------------------------- 805-00396 99.76 3.83 6.00 ----------------------------------------------- System 99.76 3.83 6.00 ***************** Link Flow Summary ***************** ------------------------------------------------------------------------------------------------- ------------------------------- Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 252 429 of 628 Link ID Element Time of Maximum Length Peak Flow Design Ratio of Ratio of Total Reported Type Peak Flow Velocity Factor during Flow Maximum Maximum Time Condition Occurrence Attained Analysis Capacity /Design Flow Surcharged days hh:mm ft/sec cfs cfs Flow Depth minutes ------------------------------------------------------------------------------------------------- ------------------------------- Link-01 CONDUIT 0 08:00 4.32 1.00 0.21 8.42 0.03 0.11 0 Calculated Link-02 CONDUIT 0 08:00 3.45 1.00 0.26 6.09 0.04 0.57 0 Calculated Link-03 CONDUIT 0 08:15 4.38 1.00 3.14 7.79 0.40 1.00 156 SURCHARGED Link-04 CHANNEL 0 07:58 1.17 1.00 2.23 95.53 0.02 1.00 117 FLOODED Link-05 CONDUIT 0 09:54 7.44 1.00 5.84 8.40 0.70 1.00 261 SURCHARGED Link-06 CONDUIT 0 08:00 7.65 1.00 6.00 4.52 1.33 1.00 306 SURCHARGED Link-12 CONDUIT 0 08:15 3.68 1.00 0.49 9.87 0.05 0.23 0 Calculated Link-13 CONDUIT 0 08:15 4.21 1.00 0.80 9.10 0.09 0.38 0 Calculated Link-14 CONDUIT 0 08:31 6.45 1.00 3.40 4.75 0.71 0.64 0 Calculated Link-15 CONDUIT 0 08:30 5.20 1.00 3.59 4.83 0.74 0.82 0 Calculated Link-16 CONDUIT 0 09:15 4.84 1.00 3.14 1.35 2.33 0.77 0 > CAPACITY Link-17 CONDUIT 0 08:05 6.70 1.00 3.14 5.82 0.54 0.77 0 Calculated Link-18 CONDUIT 0 10:37 3.88 1.00 3.04 3.27 0.93 1.00 240 SURCHARGED Link-19 CONDUIT 0 08:15 4.36 1.00 3.20 2.12 1.51 0.88 0 > CAPACITY Link-20 CONDUIT 0 08:15 4.84 1.00 3.44 4.12 0.84 0.85 0 Calculated Link-21 CONDUIT 0 07:41 2.92 1.00 2.30 1.94 1.18 1.00 760 SURCHARGED Link-22 CHANNEL 0 16:03 0.83 1.00 2.29 28.85 0.08 0.59 0 Calculated Link-23 CONDUIT 0 07:41 2.92 1.00 2.30 2.53 0.91 1.00 760 SURCHARGED Link-24 CONDUIT 0 08:15 6.37 1.00 2.50 9.95 0.25 0.54 0 Calculated Link-25 CHANNEL 0 08:15 1.30 1.00 2.50 60.03 0.04 0.47 0 Calculated Link-26 CONDUIT 0 08:16 3.38 1.00 2.56 1.20 2.13 0.93 0 > CAPACITY Link-27 CONDUIT 0 08:15 4.45 1.00 2.96 5.24 0.56 0.84 0 Calculated Link-28 CONDUIT 0 08:15 5.01 1.00 2.96 3.17 0.93 0.88 0 Calculated Link-29 CHANNEL 0 08:17 0.75 1.00 2.94 67.33 0.04 0.61 0 Calculated Link-30 CONDUIT 0 08:22 4.53 1.00 3.13 3.30 0.95 0.95 0 Calculated Link-31 CHANNEL 0 08:21 1.10 1.00 3.14 35.57 0.09 0.72 0 Calculated Link-32 CONDUIT 0 08:20 5.34 1.00 3.75 2.93 1.28 1.00 106 SURCHARGED Link-33 CHANNEL 0 08:20 1.87 1.00 3.75 58.37 0.06 0.88 0 Calculated Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 253 430 of 628 Link-34 CONDUIT 0 08:52 5.13 1.00 4.03 6.06 0.66 1.00 496 SURCHARGED Link-35 CONDUIT 0 08:15 1.27 1.00 0.83 11.77 0.07 1.00 114 SURCHARGED Link-36 CONDUIT 0 08:15 6.07 1.00 4.77 2.36 2.02 1.00 112 SURCHARGED Link-37 CHANNEL 0 08:15 2.23 1.00 4.77 27.20 0.18 0.56 0 Calculated Link-38 CONDUIT 0 08:16 7.47 1.00 4.76 6.82 0.70 0.76 0 Calculated Link-39 CHANNEL 0 08:16 3.19 1.00 4.76 241.22 0.02 0.59 0 Calculated Link-40 CONDUIT 0 08:45 3.39 1.00 2.67 2.87 0.93 1.00 109 SURCHARGED Link-41 CONDUIT 0 08:45 3.39 1.00 2.67 2.11 1.26 1.00 104 SURCHARGED Link-42 CONDUIT 0 08:45 3.39 1.00 2.67 2.11 1.26 1.00 63 SURCHARGED Link-43 CONDUIT 0 08:45 4.69 1.00 2.67 2.44 1.09 0.69 0 > CAPACITY Link-45 CONDUIT 0 08:45 5.15 1.00 2.67 18.12 0.15 0.34 0 Calculated ******************************** Highest Flow Instability Indexes ******************************** All links are stable. WARNING 116 : Conduit inlet invert elevation defined for Conduit Link-03 is below upstream node invert elevation. Assumed conduit inlet invert elevation equal to upstream node invert elevation. WARNING 116 : Conduit inlet invert elevation defined for Conduit Link-04 is below upstream node invert elevation. Assumed conduit inlet invert elevation equal to upstream node invert elevation. WARNING 116 : Conduit inlet invert elevation defined for Conduit Link-19 is below upstream node invert elevation. Assumed conduit inlet invert elevation equal to upstream node invert elevation. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 305-00320. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00307. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00314. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00315. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00316. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00321. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00322. Analysis began on: Mon Jul 27 11:17:04 2020 Analysis ended on: Mon Jul 27 11:17:12 2020 Total elapsed time: 00:00:08 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 254 431 of 628 255DevelopedConditions19.24 ac1.31 ac0.87 ac2.25 ac0.50 ac1.42 ac0.49 ac0.53 ac0.45 ac0.43 ac0.13 ac0.92 ac0.45 ac1.97 ac1.18 ac2.20 ac11.97 ac0.11 ac0.05 ac0.26 acHighlighted propertieswould continue to drainto the roadside ditchesand culverts432 of 628 256DevelopedConditions withproject25-yr flowsProfile 1Profile 2Profile 3Profile 4Profile 5433 of 628 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis257Proposed25-yr stormProfile #1Connectionto existingProposed Pond Discharge434 of 628 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis258Proposed25-yr stormProfile #2435 of 628 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis259Proposed25-yr stormProfile #3436 of 628 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis260Proposed25-yr stormProfile #4437 of 628 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis261Proposed25-yr stormProfile #5438 of 628 262DevelopedConditions withproject100-yr flowsproposed stormimprovementsred is a surchargedpipeExisting ditch andculverts to remain439 of 628 263Proposedimprovements440 of 628 Autodesk® Storm and Sanitary Analysis 2016 - Version 12.0.42 (Build 0) ----------------------------------------------------------------------------------------- ******************* Project Description ******************* File Name ................. 18355-ds-prop with project.SPF **************** Analysis Options **************** Flow Units ................ cfs Subbasin Hydrograph Method. Santa Barbara UH Time of Concentration...... SCS TR-55 Link Routing Method ....... Hydrodynamic Storage Node Exfiltration.. None Starting Date ............. MAR-05-2019 00:00:00 Ending Date ............... MAR-06-2019 00:00:00 Report Time Step .......... 00:00:10 ************* Element Count ************* Number of rain gages ...... 1 Number of subbasins ....... 20 Number of nodes ........... 44 Number of links ........... 43 **************** Raingage Summary **************** Gage Data Data Recording ID Source Type Interval min ------------------------------------------------------------ Rain Gage-01 TS-01 CUMULATIVE 15.00 **************** Subbasin Summary **************** Subbasin Total Imperv. Raingage Area Area ID acres % ---------------------------------------------------- BasinstoPond 19.24 5.00 Rain Gage-01 Sub-292 0.45 45.00 Rain Gage-01 Sub-293 0.53 58.00 Rain Gage-01 Sub-294 0.49 60.00 Rain Gage-01 Sub-295 2.25 50.00 Rain Gage-01 Sub-300 1.42 40.00 Rain Gage-01 Sub-301 0.50 50.00 Rain Gage-01 Sub-303 0.87 30.00 Rain Gage-01 Sub-304 1.31 40.00 Rain Gage-01 Sub-307 0.43 58.00 Rain Gage-01 Sub-309 0.13 38.00 Rain Gage-01 Sub-310 0.92 55.00 Rain Gage-01 Sub-313 0.45 57.00 Rain Gage-01 Sub-315 1.97 38.00 Rain Gage-01 Sub-317 1.18 63.00 Rain Gage-01 Sub-319 2.20 45.00 Rain Gage-01 Sub-323 11.97 25.00 Rain Gage-01 Sub-324 0.11 75.00 Rain Gage-01 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 264 441 of 628 Sub-327 0.05 75.00 Rain Gage-01 Sub-328 0.26 75.00 Rain Gage-01 ************ Node Summary ************ Node Element Invert Maximum Ponded External ID Type Elevation Elev. Area Inflow ft ft ft² ------------------------------------------------------------------------------ 305-00320 JUNCTION 337.35 339.35 0.00 804-00293 JUNCTION 347.20 352.11 0.00 804-00294 JUNCTION 350.73 353.25 0.00 804-00295 JUNCTION 352.69 354.83 0.00 804-00299 JUNCTION 357.13 359.24 0.00 804-00300 JUNCTION 357.36 359.55 0.00 804-00301 JUNCTION 368.84 371.49 0.00 804-00302 JUNCTION 377.67 379.22 0.00 805-00292 JUNCTION 343.16 346.00 0.00 805-00303 JUNCTION 379.62 382.08 0.00 805-00305 JUNCTION 343.03 344.54 0.00 805-00306 JUNCTION 343.24 344.50 0.00 805-00307 JUNCTION 343.31 344.56 0.00 805-00308 JUNCTION 342.06 344.20 0.00 805-00309 JUNCTION 341.40 343.60 0.00 805-00310 JUNCTION 341.44 343.57 0.00 805-00311 JUNCTION 340.71 343.15 0.00 805-00312 JUNCTION 340.66 342.90 0.00 805-00313 JUNCTION 339.85 342.00 0.00 805-00314 JUNCTION 340.06 342.06 0.00 805-00315 JUNCTION 338.92 340.92 0.00 805-00316 JUNCTION 338.70 340.72 0.00 805-00317 JUNCTION 338.06 340.06 0.00 805-00318 JUNCTION 338.07 339.90 0.00 805-00319 JUNCTION 337.24 339.90 0.00 805-00321 JUNCTION 337.18 339.18 0.00 805-00322 JUNCTION 336.63 339.63 0.00 805-00323 JUNCTION 333.69 338.00 0.00 805-00324 JUNCTION 331.88 337.00 0.00 805-00325 JUNCTION 333.88 337.50 0.00 805-00326 JUNCTION 335.32 338.50 0.00 805-00327 JUNCTION 337.52 339.52 0.00 805-00328 JUNCTION 340.85 342.90 0.00 CB#19 JUNCTION 387.00 395.41 0.00 CB#20 JUNCTION 387.75 416.10 0.00 CB#21 JUNCTION 388.50 407.42 0.00 CB#22 JUNCTION 389.25 396.00 0.00 CB#23 JUNCTION 390.00 396.00 0.00 Jun-06 JUNCTION 382.59 384.51 0.00 R1 JUNCTION 342.96 346.16 0.00 R2 JUNCTION 339.90 343.10 0.00 R3 JUNCTION 336.80 340.00 0.00 R4 JUNCTION 334.90 338.10 0.00 805-00396 OUTFALL 330.00 331.50 0.00 ************ Link Summary ************ Link From Node To Node Element Length Slope Manning's ID Type ft % Roughness -------------------------------------------------------------------------------------------- Link-01 805-00328 805-00327 CONDUIT 68.3 4.7584 0.0120 Link-02 805-00327 805-00324 CONDUIT 144.8 2.4865 0.0120 Link-03 805-00326 805-00325 CONDUIT 22.6 6.3717 0.0150 Link-04 805-00325 805-00323 CHANNEL 22.5 0.8444 0.0320 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 265 442 of 628 Link-05 805-00323 805-00324 CONDUIT 38.3 4.7320 0.0120 Link-06 805-00324 805-00396 CONDUIT 139.0 1.3740 0.0120 Link-12 Jun-06 805-00303 CONDUIT 45.1 6.5854 0.0120 Link-13 805-00303 804-00302 CONDUIT 38.9 5.2699 0.0120 Link-14 804-00302 804-00301 CONDUIT 141.9 6.1945 0.0240 Link-15 804-00301 804-00300 CONDUIT 182.0 6.2582 0.0240 Link-17 804-00299 804-00295 CONDUIT 43.8 9.1096 0.0240 Link-18 804-00295 804-00294 CONDUIT 68.3 2.8697 0.0240 Link-19 804-00294 804-00293 CONDUIT 79.5 1.2075 0.0240 Link-20 804-00293 805-00292 CONDUIT 125.1 3.2294 0.0120 Link-22 805-00307 805-00306 CHANNEL 73.1 0.0958 0.0320 Link-23 805-00306 805-00305 CONDUIT 54.2 0.3875 0.0240 Link-24 805-00307 805-00308 CONDUIT 18.8 6.6489 0.0120 Link-25 805-00308 805-00309 CHANNEL 29.8 2.0805 0.0320 Link-26 805-00310 805-00309 CONDUIT 10.3 0.3883 0.0240 Link-27 805-00310 805-00311 CONDUIT 47.2 1.8432 0.0120 Link-28 805-00311 805-00312 CONDUIT 7.4 0.6757 0.0120 Link-29 805-00312 805-00313 CHANNEL 56.7 1.4286 0.0320 Link-30 805-00314 805-00313 CONDUIT 28.8 0.7292 0.0120 Link-31 805-00314 805-00315 CHANNEL 122.1 0.9337 0.0500 Link-32 805-00315 805-00316 CONDUIT 38.1 0.5774 0.0120 Link-33 805-00316 805-00317 CHANNEL 39.4 1.6751 0.0320 Link-34 805-00317 805-00319 CONDUIT 31.6 2.4684 0.0120 Link-35 805-00318 805-00319 CONDUIT 8.5 9.2941 0.0120 Link-36 305-00320 805-00319 CONDUIT 29.3 0.3754 0.0120 Link-37 305-00320 805-00321 CHANNEL 30.4 0.5592 0.0320 Link-38 805-00321 805-00322 CONDUIT 17.6 3.1250 0.0120 Link-39 805-00322 805-00323 CHANNEL 54.6 5.3846 0.0320 Link-40 CB#23 CB#22 CONDUIT 136.0 0.5515 0.0120 Link-41 CB#22 CB#21 CONDUIT 250.0 0.3000 0.0120 Link-42 CB#21 CB#20 CONDUIT 250.0 0.3000 0.0120 Link-43 CB#20 CB#19 CONDUIT 187.2 0.4006 0.0120 Link-44 CB#19 804-00302 CONDUIT 224.0 4.1652 0.0120 Link-45 804-00300 804-00293 CONDUIT 171.0 5.9422 0.0120 Link-46 805-00292 R1 CONDUIT 77.0 0.2597 0.0120 Link-47 R1 R2 CONDUIT 244.7 1.2507 0.0120 Link-48 R2 R3 CONDUIT 171.0 1.8129 0.0120 Link-49 R3 R4 CONDUIT 148.0 1.2838 0.0120 Link-50 R4 805-00324 CONDUIT 118.8 2.5084 0.0120 ********************* Cross Section Summary ********************* Link Shape Depth/ Width No. of Cross Full Flow Design ID Diameter Barrels Sectional Hydraulic Flow Area Radius Capacity ft ft ft² ft cfs ------------------------------------------------------------------------------------------------- --------- Link-01 CIRCULAR 1.00 1.00 1 0.79 0.25 8.42 Link-02 CIRCULAR 1.00 1.00 1 0.79 0.25 6.09 Link-03 CIRCULAR 1.00 1.00 1 0.79 0.25 7.79 Link-04 TRAPEZOIDAL 3.00 10.90 1 17.85 1.40 95.53 Link-05 CIRCULAR 1.00 1.00 1 0.79 0.25 8.40 Link-06 CIRCULAR 1.50 1.50 1 1.77 0.38 13.34 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 266 443 of 628 Link-12 CIRCULAR 1.00 1.00 1 0.79 0.25 9.90 Link-13 CIRCULAR 1.00 1.00 1 0.79 0.25 8.86 Link-14 CIRCULAR 1.00 1.00 1 0.79 0.25 4.80 Link-15 CIRCULAR 1.00 1.00 1 0.79 0.25 4.83 Link-17 CIRCULAR 1.00 1.00 1 0.79 0.25 5.82 Link-18 CIRCULAR 1.00 1.00 1 0.79 0.25 3.27 Link-19 CIRCULAR 1.00 1.00 1 0.79 0.25 2.12 Link-20 CIRCULAR 1.00 1.00 1 0.79 0.25 6.94 Link-22 TRAPEZOIDAL 1.25 6.75 1 4.53 0.63 4.76 Link-23 CIRCULAR 1.00 1.00 1 0.79 0.25 1.20 Link-24 CIRCULAR 1.00 1.00 1 0.79 0.25 9.95 Link-25 TRAPEZOIDAL 1.00 4.50 1 2.50 0.50 10.56 Link-26 CIRCULAR 1.00 1.00 1 0.79 0.25 1.20 Link-27 CIRCULAR 1.00 1.00 1 0.79 0.25 5.24 Link-28 CIRCULAR 1.00 1.00 1 0.79 0.25 3.17 Link-29 TRAPEZOIDAL 1.00 6.40 1 4.20 0.61 16.85 Link-30 CIRCULAR 1.00 1.00 1 0.79 0.25 3.30 Link-31 TRAPEZOIDAL 2.00 9.90 1 11.80 1.08 35.57 Link-32 CIRCULAR 1.00 1.00 1 0.79 0.25 2.93 Link-33 TRAPEZOIDAL 2.00 7.40 1 9.40 1.07 59.28 Link-34 CIRCULAR 1.00 1.00 1 0.79 0.25 6.06 Link-35 CIRCULAR 1.00 1.00 1 0.79 0.25 11.77 Link-36 CIRCULAR 1.00 1.00 1 0.79 0.25 2.36 Link-37 TRAPEZOIDAL 2.00 8.30 1 8.40 0.90 27.20 Link-38 CIRCULAR 1.00 1.00 1 0.79 0.25 6.82 Link-39 TRAPEZOIDAL 3.00 10.90 1 17.85 1.40 241.22 Link-40 CIRCULAR 1.00 1.00 1 0.79 0.25 2.87 Link-41 CIRCULAR 1.00 1.00 1 0.79 0.25 2.11 Link-42 CIRCULAR 1.00 1.00 1 0.79 0.25 2.11 Link-43 CIRCULAR 1.00 1.00 1 0.79 0.25 2.44 Link-44 CIRCULAR 1.00 1.00 1 0.79 0.25 7.88 Link-45 CIRCULAR 1.00 1.00 1 0.79 0.25 9.41 Link-46 CIRCULAR 1.25 1.25 1 1.23 0.31 3.57 Link-47 CIRCULAR 1.25 1.25 1 1.23 0.31 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 267 444 of 628 7.83 Link-48 CIRCULAR 1.25 1.25 1 1.23 0.31 9.42 Link-49 CIRCULAR 1.25 1.25 1 1.23 0.31 7.93 Link-50 CIRCULAR 1.25 1.25 1 1.23 0.31 11.08 ************************** Volume Depth Runoff Quantity Continuity acre-ft inches ************************** --------- ------- Total Precipitation ...... 15.495 3.981 Surface Runoff ........... 7.565 1.944 Continuity Error (%) ..... -0.000 ************************** Volume Volume Flow Routing Continuity acre-ft Mgallons ************************** --------- --------- External Inflow .......... 0.000 0.000 External Outflow ......... 7.538 2.456 Initial Stored Volume .... 0.000 0.000 Final Stored Volume ...... 0.024 0.008 Continuity Error (%) ..... 0.000 ****************************************** Composite Curve Number Computations Report ****************************************** ------------------------ Subbasin BasinstoPond ------------------------ Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 19.24 71.40 ------------------- Subbasin Sub-292 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.45 85.35 ------------------- Subbasin Sub-293 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.53 88.34 ------------------- Subbasin Sub-294 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.49 88.80 ------------------- Subbasin Sub-295 ------------------- Area Soil Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 268 445 of 628 Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 2.25 84.00 ------------------- Subbasin Sub-300 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 1.42 84.20 ------------------- Subbasin Sub-301 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.50 86.50 ------------------- Subbasin Sub-303 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.87 81.90 ------------------- Subbasin Sub-304 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 1.31 84.20 ------------------- Subbasin Sub-307 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.43 88.34 ------------------- Subbasin Sub-309 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.13 83.74 ------------------- Subbasin Sub-310 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.92 87.65 ------------------- Subbasin Sub-313 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.45 88.11 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 269 446 of 628 ------------------- Subbasin Sub-315 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 1.97 83.74 ------------------- Subbasin Sub-317 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 1.18 89.49 ------------------- Subbasin Sub-319 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 2.20 85.35 ------------------- Subbasin Sub-323 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 11.97 78.50 ------------------- Subbasin Sub-324 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.11 94.75 ------------------- Subbasin Sub-327 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.05 94.75 ------------------- Subbasin Sub-328 ------------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.26 94.75 ************************************** Runoff Coefficient Computations Report ************************************** ------------------------ Subbasin BasinstoPond ------------------------ Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 270 447 of 628 - 19.24 - 0.72 Composite Area & Weighted Runoff Coeff. 19.24 0.72 ------------------- Subbasin Sub-292 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.45 - 0.72 Composite Area & Weighted Runoff Coeff. 0.45 0.72 ------------------- Subbasin Sub-293 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.53 - 0.72 Composite Area & Weighted Runoff Coeff. 0.53 0.72 ------------------- Subbasin Sub-294 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.49 - 0.72 Composite Area & Weighted Runoff Coeff. 0.49 0.72 ------------------- Subbasin Sub-295 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 2.25 - 0.72 Composite Area & Weighted Runoff Coeff. 2.25 0.72 ------------------- Subbasin Sub-300 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 1.42 - 0.72 Composite Area & Weighted Runoff Coeff. 1.42 0.72 ------------------- Subbasin Sub-301 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.50 - 0.72 Composite Area & Weighted Runoff Coeff. 0.50 0.72 ------------------- Subbasin Sub-303 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.87 - 0.72 Composite Area & Weighted Runoff Coeff. 0.87 0.72 ------------------- Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 271 448 of 628 Subbasin Sub-304 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 1.31 - 0.72 Composite Area & Weighted Runoff Coeff. 1.31 0.72 ------------------- Subbasin Sub-307 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.43 - 0.72 Composite Area & Weighted Runoff Coeff. 0.43 0.72 ------------------- Subbasin Sub-309 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.13 - 0.72 Composite Area & Weighted Runoff Coeff. 0.13 0.72 ------------------- Subbasin Sub-310 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.92 - 0.72 Composite Area & Weighted Runoff Coeff. 0.92 0.72 ------------------- Subbasin Sub-313 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.45 - 0.72 Composite Area & Weighted Runoff Coeff. 0.45 0.72 ------------------- Subbasin Sub-315 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 1.97 - 0.72 Composite Area & Weighted Runoff Coeff. 1.97 0.72 ------------------- Subbasin Sub-317 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 1.18 - 0.72 Composite Area & Weighted Runoff Coeff. 1.18 0.72 ------------------- Subbasin Sub-319 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 272 449 of 628 ----------------------------------------------------------------------------------------- - 2.20 - 0.72 Composite Area & Weighted Runoff Coeff. 2.20 0.72 ------------------- Subbasin Sub-323 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 11.97 - 0.72 Composite Area & Weighted Runoff Coeff. 11.97 0.72 ------------------- Subbasin Sub-324 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.11 - 0.72 Composite Area & Weighted Runoff Coeff. 0.11 0.72 ------------------- Subbasin Sub-327 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.05 - 0.72 Composite Area & Weighted Runoff Coeff. 0.05 0.72 ------------------- Subbasin Sub-328 ------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.26 - 0.72 Composite Area & Weighted Runoff Coeff. 0.26 0.72 *************************************************** SCS TR-55 Time of Concentration Computations Report *************************************************** Sheet Flow Equation ------------------- Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where: Tc = Time of Concentration (hrs) n = Manning's Roughness Lf = Flow Length (ft) P = 2 yr, 24 hr Rainfall (inches) Sf = Slope (ft/ft) Shallow Concentrated Flow Equation ---------------------------------- V = 16.1345 * (Sf^0.5) (unpaved surface) V = 20.3282 * (Sf^0.5) (paved surface) V = 15.0 * (Sf^0.5) (grassed waterway surface) V = 10.0 * (Sf^0.5) (nearly bare & untilled surface) V = 9.0 * (Sf^0.5) (cultivated straight rows surface) V = 7.0 * (Sf^0.5) (short grass pasture surface) Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 273 450 of 628 V = 5.0 * (Sf^0.5) (woodland surface) V = 2.5 * (Sf^0.5) (forest w/heavy litter surface) Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) Channel Flow Equation --------------------- V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n R = Aq / Wp Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) R = Hydraulic Radius (ft) Aq = Flow Area (ft²) Wp = Wetted Perimeter (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) n = Manning's Roughness ------------------------ Subbasin BasinstoPond ------------------------ Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.80 0.00 0.00 Flow Length (ft): 200.00 0.00 0.00 Slope (%): 16.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.09 0.00 0.00 Computed Flow Time (minutes): 35.84 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 1385.00 0.00 0.00 Slope (%): 7.00 0.00 0.00 Surface Type: Woodland Unpaved Unpaved Velocity (ft/sec): 1.32 0.00 0.00 Computed Flow Time (minutes): 17.49 0.00 0.00 Channel Flow Computations ------------------------- Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 274 451 of 628 Subarea A Subarea B Subarea C Manning's Roughness: 0.10 0.00 0.00 Flow Length (ft): 400.00 0.00 0.00 Channel Slope (%): 7.00 0.00 0.00 Cross Section Area (ft²): 7.50 0.00 0.00 Wetted Perimeter (ft): 30.00 0.00 0.00 Velocity (ft/sec): 1.56 0.00 0.00 Computed Flow Time (minutes): 4.26 0.00 0.00 ================================================================================================ Total TOC (minutes): 57.59 ================================================================================================ ------------------- Subbasin Sub-292 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 200.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.13 0.00 0.00 Computed Flow Time (minutes): 24.84 0.00 0.00 ================================================================================================ Total TOC (minutes): 24.84 ================================================================================================ ------------------- Subbasin Sub-293 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 280.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.14 0.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 275 452 of 628 0.00 Computed Flow Time (minutes): 32.52 0.00 0.00 ================================================================================================ Total TOC (minutes): 32.52 ================================================================================================ ------------------- Subbasin Sub-294 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 ================================================================================================ Total TOC (minutes): 34.36 ================================================================================================ ------------------- Subbasin Sub-295 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 450.00 0.00 0.00 Slope (%): 4.00 0.00 0.00 Surface Type: Paved Unpaved Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 276 453 of 628 Unpaved Velocity (ft/sec): 4.07 0.00 0.00 Computed Flow Time (minutes): 1.84 0.00 0.00 ================================================================================================ Total TOC (minutes): 36.20 ================================================================================================ ------------------- Subbasin Sub-300 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 11.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 33.08 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 150.00 0.00 0.00 Slope (%): 6.00 0.00 0.00 Surface Type: Paved Unpaved Unpaved Velocity (ft/sec): 4.98 0.00 0.00 Computed Flow Time (minutes): 0.50 0.00 0.00 ================================================================================================ Total TOC (minutes): 33.58 ================================================================================================ ------------------- Subbasin Sub-301 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 250.00 0.00 0.00 Slope (%): 12.00 0.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 277 454 of 628 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 27.61 0.00 0.00 ================================================================================================ Total TOC (minutes): 27.61 ================================================================================================ ------------------- Subbasin Sub-303 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 200.00 0.00 0.00 Slope (%): 5.70 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.11 0.00 0.00 Computed Flow Time (minutes): 31.11 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 250.00 0.00 0.00 Slope (%): 12.00 0.00 0.00 Surface Type: Paved Unpaved Unpaved Velocity (ft/sec): 7.04 0.00 0.00 Computed Flow Time (minutes): 0.59 0.00 0.00 ================================================================================================ Total TOC (minutes): 31.70 ================================================================================================ ------------------- Subbasin Sub-304 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.50 0.00 0.00 Flow Length (ft): 250.00 0.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 278 455 of 628 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.12 0.00 0.00 Computed Flow Time (minutes): 35.50 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 500.00 0.00 0.00 Slope (%): 4.00 0.00 0.00 Surface Type: Paved Unpaved Unpaved Velocity (ft/sec): 4.07 0.00 0.00 Computed Flow Time (minutes): 2.05 0.00 0.00 ================================================================================================ Total TOC (minutes): 37.55 ================================================================================================ ------------------- Subbasin Sub-307 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 200.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.13 0.00 0.00 Computed Flow Time (minutes): 24.84 0.00 0.00 ================================================================================================ Total TOC (minutes): 24.84 ================================================================================================ ------------------- Subbasin Sub-309 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 279 456 of 628 0.00 Flow Length (ft): 150.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.13 0.00 0.00 Computed Flow Time (minutes): 19.74 0.00 0.00 ================================================================================================ Total TOC (minutes): 19.74 ================================================================================================ ------------------- Subbasin Sub-310 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 250.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 Surface Type: Grass pasture Unpaved Unpaved Velocity (ft/sec): 2.21 0.00 0.00 Computed Flow Time (minutes): 1.89 0.00 0.00 ================================================================================================ Total TOC (minutes): 36.25 ================================================================================================ ------------------- Subbasin Sub-313 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 280 457 of 628 C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 100.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 Surface Type: Grass pasture Unpaved Unpaved Velocity (ft/sec): 2.21 0.00 0.00 Computed Flow Time (minutes): 0.75 0.00 0.00 ================================================================================================ Total TOC (minutes): 35.12 ================================================================================================ ------------------- Subbasin Sub-315 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 250.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 Surface Type: Grass pasture Unpaved Unpaved Velocity (ft/sec): 2.21 0.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 281 458 of 628 0.00 Computed Flow Time (minutes): 1.89 0.00 0.00 ================================================================================================ Total TOC (minutes): 36.25 ================================================================================================ ------------------- Subbasin Sub-317 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.15 0.00 0.00 Computed Flow Time (minutes): 34.36 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 220.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 Surface Type: Grass pasture Unpaved Unpaved Velocity (ft/sec): 2.21 0.00 0.00 Computed Flow Time (minutes): 1.66 0.00 0.00 ================================================================================================ Total TOC (minutes): 36.02 ================================================================================================ ------------------- Subbasin Sub-319 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 7.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 282 459 of 628 2.00 Velocity (ft/sec): 0.13 0.00 0.00 Computed Flow Time (minutes): 39.63 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 350.00 0.00 0.00 Slope (%): 10.00 0.00 0.00 Surface Type: Grassed waterway Unpaved Unpaved Velocity (ft/sec): 4.74 0.00 0.00 Computed Flow Time (minutes): 1.23 0.00 0.00 Channel Flow Computations ------------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.01 0.00 0.00 Flow Length (ft): 250.00 0.00 0.00 Channel Slope (%): 1.00 0.00 0.00 Cross Section Area (ft²): 0.79 0.00 0.00 Wetted Perimeter (ft): 3.14 0.00 0.00 Velocity (ft/sec): 4.95 0.00 0.00 Computed Flow Time (minutes): 0.84 0.00 0.00 ================================================================================================ Total TOC (minutes): 41.70 ================================================================================================ ------------------- Subbasin Sub-323 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 300.00 0.00 0.00 Slope (%): 8.50 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.14 0.00 0.00 Computed Flow Time (minutes): 36.67 0.00 0.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 283 460 of 628 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 700.00 0.00 0.00 Slope (%): 9.00 0.00 0.00 Surface Type: Woodland Unpaved Unpaved Velocity (ft/sec): 1.50 0.00 0.00 Computed Flow Time (minutes): 7.78 0.00 0.00 ================================================================================================ Total TOC (minutes): 44.45 ================================================================================================ ------------------- Subbasin Sub-324 ------------------- User-Defined TOC override (minutes): 6.30 ------------------- Subbasin Sub-327 ------------------- User-Defined TOC override (minutes): 6.30 ------------------- Subbasin Sub-328 ------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.01 0.00 0.00 Flow Length (ft): 380.00 0.00 0.00 Slope (%): 1.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 2.00 2.00 2.00 Velocity (ft/sec): 0.84 0.00 0.00 Computed Flow Time (minutes): 7.54 0.00 0.00 ================================================================================================ Total TOC (minutes): 7.54 ================================================================================================ *********************** Subbasin Runoff Summary *********************** -------------------------------------------------------------------------- Subbasin Total Total Peak Weighted Time of ID Precip Runoff Runoff Curve Concentration Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 284 461 of 628 in in cfs Number days hh:mm:ss -------------------------------------------------------------------------- BasinstoPond 3.98 1.39 2.67 71.400 0 00:57:35 Sub-292 3.98 2.57 0.20 85.350 0 00:24:50 Sub-293 3.98 2.84 0.25 88.340 0 00:32:31 Sub-294 3.98 2.88 0.23 88.800 0 00:34:21 Sub-295 3.98 2.50 0.86 84.000 0 00:36:12 Sub-300 3.98 2.46 0.56 84.200 0 00:33:34 Sub-301 3.98 2.68 0.23 86.500 0 00:27:36 Sub-303 3.98 2.25 0.31 81.900 0 00:31:42 Sub-304 3.98 2.46 0.49 84.200 0 00:37:33 Sub-307 3.98 2.85 0.22 88.340 0 00:24:50 Sub-309 3.98 2.43 0.06 83.740 0 00:19:44 Sub-310 3.98 2.77 0.40 87.650 0 00:36:15 Sub-313 3.98 2.81 0.21 88.110 0 00:35:07 Sub-315 3.98 2.42 0.73 83.740 0 00:36:15 Sub-317 3.98 2.94 0.56 89.490 0 00:36:01 Sub-319 3.98 2.55 0.83 85.350 0 00:41:42 Sub-323 3.98 1.98 3.14 78.500 0 00:44:27 Sub-324 3.98 3.42 0.09 94.750 0 00:06:18 Sub-327 3.98 3.42 0.04 94.750 0 00:06:18 Sub-328 3.98 3.42 0.21 94.750 0 00:07:32 -------------------------------------------------------------------------- ****************** Node Depth Summary ****************** ----------------------------------------------------------------------------------------- Node Average Maximum Maximum Time of Max Total Total Retention ID Depth Depth HGL Occurrence Flooded Time Time Attained Attained Attained Volume Flooded ft ft ft days hh:mm acre-in minutes hh:mm:ss ----------------------------------------------------------------------------------------- 305-00320 0.57 0.89 338.24 0 08:17 0 0 0:00:00 804-00293 0.40 0.81 348.01 0 08:18 0 0 0:00:00 804-00294 0.29 0.55 351.28 0 08:15 0 0 0:00:00 804-00295 0.19 0.35 353.04 0 08:15 0 0 0:00:00 804-00299 0.00 0.00 357.13 0 00:00 0 0 0:00:00 804-00300 0.29 0.46 357.82 0 08:29 0 0 0:00:00 804-00301 0.40 0.66 369.50 0 08:31 0 0 0:00:00 804-00302 0.39 0.64 378.31 0 08:30 0 0 0:00:00 805-00292 0.77 1.65 344.81 0 08:18 0 0 0:00:00 805-00303 0.21 0.30 379.92 0 08:15 0 0 0:00:00 805-00305 0.33 0.38 343.41 0 08:16 0 0 0:00:00 805-00306 0.12 0.17 343.41 0 08:15 0 0 0:00:00 805-00307 0.05 0.10 343.41 0 08:15 0 0 0:00:00 805-00308 0.08 0.17 342.23 0 08:15 0 0 0:00:00 805-00309 0.35 0.49 341.89 0 08:15 0 0 0:00:00 805-00310 0.30 0.43 341.87 0 08:15 0 0 0:00:00 805-00311 0.19 0.37 341.08 0 08:15 0 0 0:00:00 805-00312 0.09 0.18 340.84 0 08:15 0 0 0:00:00 805-00313 0.49 0.77 340.62 0 08:16 0 0 0:00:00 805-00314 0.16 0.31 340.37 0 08:17 0 0 0:00:00 805-00315 0.31 0.59 339.51 0 08:17 0 0 0:00:00 805-00316 0.17 0.31 339.01 0 08:17 0 0 0:00:00 805-00317 0.24 0.77 338.83 0 08:17 0 0 0:00:00 805-00318 0.14 0.59 338.66 0 08:17 0 0 0:00:00 805-00319 0.79 1.41 338.65 0 08:11 0 0 0:00:00 805-00321 0.33 0.68 337.86 0 08:17 0 0 0:00:00 805-00322 0.22 0.40 337.03 0 08:17 0 0 0:00:00 805-00323 0.41 1.49 335.18 0 08:22 0 0 0:00:00 805-00324 0.71 1.46 333.34 0 08:21 0 0 0:00:00 805-00325 0.45 1.31 335.19 0 08:22 0 0 0:00:00 805-00326 0.29 0.59 335.91 0 08:21 0 0 0:00:00 805-00327 0.06 0.14 337.66 0 08:00 0 0 0:00:00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 285 462 of 628 805-00328 0.05 0.11 340.96 0 08:00 0 0 0:00:00 CB#19 0.27 0.40 387.40 0 08:45 0 0 0:00:00 CB#20 0.58 1.19 388.94 0 08:25 0 0 0:00:00 CB#21 0.68 1.80 390.30 0 08:45 0 0 0:00:00 CB#22 0.73 2.42 391.67 0 08:45 0 0 0:00:00 CB#23 0.64 2.50 392.50 0 08:45 0 0 0:00:00 Jun-06 0.09 0.15 382.74 0 08:15 0 0 0:00:00 R1 0.49 0.86 343.82 0 08:18 0 0 0:00:00 R2 0.43 0.75 340.65 0 08:19 0 0 0:00:00 R3 0.51 0.90 337.70 0 08:19 0 0 0:00:00 R4 0.38 0.68 335.58 0 08:20 0 0 0:00:00 805-00396 0.60 1.10 331.10 0 08:21 0 0 0:00:00 ***************** Node Flow Summary ***************** ------------------------------------------------------------------------------------ Node Element Maximum Peak Time of Maximum Time of Peak ID Type Lateral Inflow Peak Inflow Flooding Flooding Inflow Occurrence Overflow Occurrence cfs cfs days hh:mm cfs days hh:mm ------------------------------------------------------------------------------------ 305-00320 JUNCTION 0.00 2.98 0 08:17 0.00 804-00293 JUNCTION 0.25 5.41 0 08:18 0.00 804-00294 JUNCTION 0.23 1.09 0 08:15 0.00 804-00295 JUNCTION 0.86 0.86 0 08:15 0.00 804-00299 JUNCTION 0.00 0.00 0 00:00 0.00 804-00300 JUNCTION 0.56 4.10 0 08:29 0.00 804-00301 JUNCTION 0.23 3.59 0 08:30 0.00 804-00302 JUNCTION 0.00 3.40 0 08:30 0.00 805-00292 JUNCTION 0.20 5.60 0 08:18 0.00 805-00303 JUNCTION 0.31 0.80 0 08:15 0.00 805-00305 JUNCTION 0.00 0.00 0 02:32 0.00 805-00306 JUNCTION 0.00 0.00 0 03:10 0.00 805-00307 JUNCTION 0.22 0.22 0 08:15 0.00 805-00308 JUNCTION 0.00 0.22 0 08:15 0.00 805-00309 JUNCTION 0.06 0.27 0 08:15 0.00 805-00310 JUNCTION 0.40 0.68 0 08:15 0.00 805-00311 JUNCTION 0.00 0.68 0 08:15 0.00 805-00312 JUNCTION 0.00 0.68 0 08:15 0.00 805-00313 JUNCTION 0.21 0.88 0 08:15 0.00 805-00314 JUNCTION 0.00 0.88 0 08:16 0.00 805-00315 JUNCTION 0.73 1.60 0 08:16 0.00 805-00316 JUNCTION 0.00 1.60 0 08:17 0.00 805-00317 JUNCTION 0.56 2.15 0 08:16 0.00 805-00318 JUNCTION 0.83 0.83 0 08:15 0.00 805-00319 JUNCTION 0.00 2.98 0 08:17 0.00 805-00321 JUNCTION 0.00 2.98 0 08:17 0.00 805-00322 JUNCTION 0.00 2.98 0 08:17 0.00 805-00323 JUNCTION 0.00 6.06 0 08:17 0.00 805-00324 JUNCTION 0.09 11.84 0 08:21 0.00 805-00325 JUNCTION 0.00 3.13 0 08:15 0.00 805-00326 JUNCTION 3.14 3.14 0 08:15 0.00 805-00327 JUNCTION 0.04 0.26 0 08:00 0.00 805-00328 JUNCTION 0.21 0.21 0 08:00 0.00 CB#19 JUNCTION 0.00 2.67 0 08:45 0.00 CB#20 JUNCTION 0.00 2.67 0 08:45 0.00 CB#21 JUNCTION 0.00 2.67 0 08:45 0.00 CB#22 JUNCTION 0.00 2.67 0 08:45 0.00 CB#23 JUNCTION 2.67 2.67 0 08:45 0.00 Jun-06 JUNCTION 0.49 0.49 0 08:15 0.00 R1 JUNCTION 0.00 5.60 0 08:18 0.00 R2 JUNCTION 0.00 5.60 0 08:19 0.00 R3 JUNCTION 0.00 5.60 0 08:19 0.00 R4 JUNCTION 0.00 5.60 0 08:19 0.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 286 463 of 628 805-00396 OUTFALL 0.00 11.84 0 08:21 0.00 *********************** Outfall Loading Summary *********************** ----------------------------------------------- Outfall Node ID Flow Average Peak Frequency Flow Inflow (%) cfs cfs ----------------------------------------------- 805-00396 99.46 4.71 11.84 ----------------------------------------------- System 99.46 4.71 11.84 ***************** Link Flow Summary ***************** ------------------------------------------------------------------------------------------------- ------------------------------- Link ID Element Time of Maximum Length Peak Flow Design Ratio of Ratio of Total Reported Type Peak Flow Velocity Factor during Flow Maximum Maximum Time Condition Occurrence Attained Analysis Capacity /Design Flow Surcharged days hh:mm ft/sec cfs cfs Flow Depth minutes ------------------------------------------------------------------------------------------------- ------------------------------- Link-01 CONDUIT 0 08:00 4.32 1.00 0.21 8.42 0.03 0.11 0 Calculated Link-02 CONDUIT 0 08:00 3.79 1.00 0.26 6.09 0.04 0.14 0 Calculated Link-03 CONDUIT 0 08:15 5.49 1.00 3.13 7.79 0.40 0.80 0 Calculated Link-04 CHANNEL 0 08:23 1.85 1.00 3.09 95.53 0.03 0.47 0 Calculated Link-05 CONDUIT 0 08:23 7.67 1.00 6.02 8.40 0.72 1.00 36 SURCHARGED Link-06 CONDUIT 0 08:21 7.52 1.00 11.84 13.34 0.89 0.84 0 Calculated Link-12 CONDUIT 0 08:15 3.65 1.00 0.49 9.90 0.05 0.23 0 Calculated Link-13 CONDUIT 0 08:15 2.89 1.00 0.80 8.86 0.09 0.42 0 Calculated Link-14 CONDUIT 0 08:30 6.51 1.00 3.40 4.80 0.71 0.63 0 Calculated Link-15 CONDUIT 0 08:31 6.63 1.00 3.59 4.83 0.74 0.65 0 Calculated Link-17 CONDUIT 0 00:00 0.00 1.00 0.00 5.82 0.00 0.00 0 Calculated Link-18 CONDUIT 0 08:15 2.52 1.00 0.86 3.27 0.26 0.45 0 Calculated Link-19 CONDUIT 0 08:15 2.82 1.00 1.09 2.12 0.51 0.49 0 Calculated Link-20 CONDUIT 0 08:18 7.23 1.00 5.41 6.94 0.78 0.91 0 Calculated Link-22 CHANNEL 0 03:10 0.13 1.00 0.00 4.76 0.00 0.11 0 Calculated Link-23 CONDUIT 0 02:32 0.23 1.00 0.00 1.20 0.00 0.28 0 Calculated Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 287 464 of 628 Link-24 CONDUIT 0 08:15 3.43 1.00 0.22 9.95 0.02 0.13 0 Calculated Link-25 CHANNEL 0 08:15 0.63 1.00 0.22 10.56 0.02 0.31 0 Calculated Link-26 CONDUIT 0 08:15 0.77 1.00 0.27 1.20 0.23 0.46 0 Calculated Link-27 CONDUIT 0 08:15 3.46 1.00 0.68 5.24 0.13 0.30 0 Calculated Link-28 CONDUIT 0 08:15 3.89 1.00 0.68 3.17 0.21 0.27 0 Calculated Link-29 CHANNEL 0 08:15 0.47 1.00 0.67 16.85 0.04 0.48 0 Calculated Link-30 CONDUIT 0 08:16 2.01 1.00 0.88 3.30 0.27 0.54 0 Calculated Link-31 CHANNEL 0 08:17 0.69 1.00 0.88 35.57 0.02 0.23 0 Calculated Link-32 CONDUIT 0 08:17 4.66 1.00 1.60 2.93 0.55 0.45 0 Calculated Link-33 CHANNEL 0 08:17 1.56 1.00 1.60 59.28 0.03 0.27 0 Calculated Link-34 CONDUIT 0 08:17 2.93 1.00 2.15 6.06 0.35 0.88 0 Calculated Link-35 CONDUIT 0 08:15 1.27 1.00 0.83 11.77 0.07 0.80 0 Calculated Link-36 CONDUIT 0 08:17 3.88 1.00 2.98 2.36 1.26 0.94 0 > CAPACITY Link-37 CHANNEL 0 08:17 2.23 1.00 2.98 27.20 0.11 0.39 0 Calculated Link-38 CONDUIT 0 08:17 6.83 1.00 2.98 6.82 0.44 0.54 0 Calculated Link-39 CHANNEL 0 08:17 2.42 1.00 2.98 241.22 0.01 0.32 0 Calculated Link-40 CONDUIT 0 08:45 3.39 1.00 2.67 2.87 0.93 1.00 109 SURCHARGED Link-41 CONDUIT 0 08:45 3.39 1.00 2.67 2.11 1.26 1.00 104 SURCHARGED Link-42 CONDUIT 0 08:45 3.39 1.00 2.67 2.11 1.26 1.00 63 SURCHARGED Link-43 CONDUIT 0 08:45 4.66 1.00 2.67 2.44 1.09 0.70 0 > CAPACITY Link-44 CONDUIT 0 08:45 6.70 1.00 2.67 7.88 0.34 0.52 0 Calculated Link-45 CONDUIT 0 08:29 8.72 1.00 4.10 9.41 0.44 0.64 0 Calculated Link-46 CONDUIT 0 08:18 5.07 1.00 5.60 3.57 1.57 0.84 0 > CAPACITY Link-47 CONDUIT 0 08:19 6.71 1.00 5.60 7.83 0.72 0.64 0 Calculated Link-48 CONDUIT 0 08:19 6.54 1.00 5.60 9.42 0.59 0.66 0 Calculated Link-49 CONDUIT 0 08:19 6.91 1.00 5.60 7.93 0.71 0.63 0 Calculated Link-50 CONDUIT 0 08:20 5.50 1.00 5.60 11.08 0.51 0.77 0 Calculated ******************************** Highest Flow Instability Indexes ******************************** All links are stable. WARNING 108 : Surcharge elevation defined for Junction 805-00309 is below junction maximum elevation. Assumed surcharge elevation equal to maximum elevation. WARNING 116 : Conduit inlet invert elevation defined for Conduit Link-03 is below upstream node invert elevation. Assumed conduit inlet invert elevation equal to upstream node invert elevation. WARNING 116 : Conduit inlet invert elevation defined for Conduit Link-04 is below upstream node Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 288 465 of 628 invert elevation. Assumed conduit inlet invert elevation equal to upstream node invert elevation. WARNING 117 : Conduit outlet invert elevation defined for Conduit Link-13 is below downstream node invert elevation. Assumed conduit outlet invert elevation equal to downstream node invert elevation. WARNING 116 : Conduit inlet invert elevation defined for Conduit Link-19 is below upstream node invert elevation. Assumed conduit inlet invert elevation equal to upstream node invert elevation. WARNING 117 : Conduit outlet invert elevation defined for Conduit Link-33 is below downstream node invert elevation. Assumed conduit outlet invert elevation equal to downstream node invert elevation. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 305-00320. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00307. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00314. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00315. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00316. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00317. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00321. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 805-00322. Analysis began on: Mon Jul 27 12:45:08 2020 Analysis ended on: Mon Jul 27 12:45:13 2020 Total elapsed time: 00:00:05 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis 289 466 of 628 Carbon Trails Residential Updated Transportation Impact Analysis July 1, 2021 Prepared for: Stowe Investments PO Box 1054 Sumner, WA 98390 Prepared by: TENW Transportation Engineering NorthWest 11400 SE 8th Street, Suite 200 Bellevue, WA 98004 Office: (425) 889-6747 467 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page i Table of Contents FINDINGS/CONCLUSIONS .................................................................................................. 1 INTRODUCTION ................................................................................................................. 2 Project Description ................................................................................................................ 2 Project Approach ................................................................................................................. 2 Primary Data and Information Sources ...................................................................................... 3 EXISTING CONDITIONS ....................................................................................................... 6 Roadway Network ............................................................................................................... 6 Existing Traffic Volumes .......................................................................................................... 6 Level of Service .................................................................................................................... 8 Collision History ................................................................................................................... 9 FUTURE TRAFFIC CONDITIONS AND PROJECT IMPACTS ........................................................ 11 Planned Transportation Improvements ..................................................................................... 11 Project Trip Generation ........................................................................................................ 11 Project Trip Distribution and Assignment .................................................................................. 12 Future Traffic Volumes .......................................................................................................... 15 Future Level of Service ......................................................................................................... 18 Site Access Analysis ............................................................................................................ 19 Level of Service ............................................................................................................... 20 MITIGATION .................................................................................................................... 21 Appendices Appendix A – Peak Hour Turning Movement Counts Appendix B – Level of Service (LOS) Calculations Appendix C – Trip Generation Calculations 468 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page ii List of Figures and Tables Figure 1 Project Site Vicinity ....................................................................................................... 4 Figure 2 Preliminary Site Plan ..................................................................................................... 5 Figure 3 2018 Existing Weekday Peak Hour Traffic Volumes ........................................................... 7 Figure 4 Project Trip Distribution ................................................................................................ 13 Figure 5 Peak Hour Project Trip Assignment................................................................................. 14 Figure 6 2023 Without Project Weekday Peak Hour Traffic Volumes .............................................. 16 Figure 7 2023 With Project Weekday Peak Hour Traffic Volumes .................................................. 17 Table 1 Existing Roadway Network Summary – Project Site Vicinity .................................................. 6 Table 2 LOS Criteria for Stop-Controlled Intersections1 ................................................................... 8 Table 3 2018 Existing AM and PM Peak Hour LOS Summary ......................................................... 9 Table 4 Collision Data Summary, January 1, 2015 to December 31, 2017 .................................... 10 Table 5 Collision Data Summary By Type, January 1, 2015 to December 31, 2017 ........................ 10 Table 6 Trip Generation Summary ............................................................................................ 11 Table 7 Project Trip Distribution................................................................................................ 12 Table 8 Year 2023 AM Peak Hour LOS Summary ...................................................................... 18 Table 9 Year 2023 PM Peak Hour LOS Summary ...................................................................... 18 Table 10 Year 2023 Peak Hour LOS Summary – With City Planned Improvement ............................ 19 Table 11 Year 2023 Peak Hour Level of Service Summary at Site Access Locations ........................... 20 469 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 1 FINDINGS/CONCLUSIONS This updated transportation impact analysis (TIA) has been prepared for the proposed Carbon Trails Residential development located between 51st Avenue S and 56th Avenue S in the vicinity of S 328th Street in Auburn, WA. This is an update to our previous study (dated April 15, 2021) and is intended to address City comments (dated June 17, 2021). Project Proposal. The proposed Carbon Trails Residential development includes up to 44 single- family dwelling units on an existing site that currently includes one single-family home, which will be removed with the proposed project. As part of the proposed project, S 328th Street would be extended between 51st Avenue S and 56th Avenue S. Vehicular access to the site would be provided at various locations along the future S 328th Street. Access for lot 44 would be provided directly onto 56th Avenue S. Full buildout of the project is estimated to occur in 2023. Trip Generation. The proposed Carbon Trails Residential development is estimated to generate 480 net new weekday daily trips, with 35 net new trips occurring during the weekday AM peak hour (9 entering, 26 exiting), and 45 net new trips occurring during the weekday PM peak hour (28 entering, 17 exiting). Future Year LOS. LOS analyses were conducted for future year 2023 weekday AM and PM peak hour conditions at four off-site study intersections. Based on the analysis results, both all-way stop- controlled study intersections and all individual movements at the two-way stop-controlled study intersections are anticipated to operate at LOS B or better during both the weekday AM and PM peak hours in 2023 with the proposed project with two exceptions. The northbound and southbound stop controlled approaches at the 46th Place S/S 321st Street intersection (#3) are anticipated to include movements that operate at LOS E/F during both the weekday AM and PM peak hours without or with the proposed project. The City of Auburn has a planned improvement at this intersection (TIP Project #R-9) that would improve safety and traffic operations. The planned improvement would include realigning 46th Place S approximately 350 feet to the east of the current location. This will create two T-intersections (44th Avenue S and 46th Place S) in place of the existing four-leg intersection. With the future realigning of 46th Place S this would result in delays at the stop controlled northbound and southbound movements that are better than pre- project conditions. It should be noted that the transportation impact fees to be paid by the project will help fund the 46th Place S realignment project. The projectÊs proportionate share impact at the intersection is 1.5 percent or less during the weekday AM and PM peak hours. Mitigation. Transportation mitigation required by the City of Auburn is payment of a transportation impact fee. The proposed Carbon Trails Residential development would include the development of up to 44 single family dwelling units on an existing site that currently includes one single family dwelling unit that would be removed as part of the proposed project. As of the date of this study, the adopted City of Auburn 2021 impact fee schedule identifies a non-downtown fee of $5,652.57 per single- family dwelling unit. The estimated transportation impact fee is $243,060.51 ($5,652.57 X 43 net single-family dwelling units). Impact fees will be assessed by the City at the time the applicant submits a complete application for a building permit. The amount of the impact fees will be adjusted to the fees in effect at the time of payment. 470 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 2 INTRODUCTION This updated transportation impact analysis (TIA) has been prepared for the proposed Carbon Trails Residential development located between 51st Avenue S and 56th Avenue S in the vicinity of S 328th Street in Auburn, WA as shown in the Figure 1 vicinity map. This is an update to our previous study (dated July 16, 2020) and is intended to address City comments (dated August 31, 2020). Project Description The proposed Carbon Trails Residential development includes up to 44 single-family dwelling units on an existing site that currently includes one single-family home, which will be removed with the proposed project. As part of the proposed project, S 328th Street would be extended between 51st Avenue S and 56th Avenue S. Vehicular access to the site would be provided at various locations along S 328th Street. Access for lot 44 would be provided directly onto 56th Avenue S. Full buildout of the project is estimated to occur in 2023. A preliminary site plan is provided in Figure 2. Project Approach To analyze the traffic impacts from the project, the following tasks were undertaken: · Assessed existing conditions through field reconnaissance and reviewed existing planning documents; · Described and assessed existing transportation conditions in the area; · Documented collision histories at study intersections; · Documented planned transportation improvements in the site vicinity; · Documented existing traffic volumes and intersection levels of service (LOS) at the following four study intersections during the weekday AM and PM peak hours: 1. 56th Avenue S / S 316th Street 2. 46th Place S / S 321st Street 3. 46th Place S / S 324th Street 4. 56th Avenue S / S 331st Street · Estimated trip generation and documented trip distribution and assignment of weekday AM and PM peak hour project-generated traffic; · Documented traffic forecasts and assumptions for year 2023 conditions at the four study intersections without and with the proposed development; · Reassigned existing traffic in the project vicinity that may use the new S 328th Street connection between 51st Avenue S and 56th Avenue S; · Analyzed weekday AM and PM peak hour LOS for year 2023 conditions at the four study intersections without and with the proposed development; · Identified transportation mitigation to the City of Auburn. 471 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 3 Primary Data and Information Sources · City of Auburn Comprehensive Transportation Plan, December 14, 2015. · City of Auburn 2022 - 2027 Transportation Improvement Program, Resolution 5597 adopted June 21, 2021. · ITE Trip Generation Manual, 10th edition, 2017. · AM and PM Peak Hour traffic counts by All Traffic Data and TC2, 2018. · Highway Capacity Manual (HCM 6th Edition), 2016. · City of Auburn Collision Data, 2015-2017. · City of Auburn Safety Priority Index System (SPIS) 2015-2017. 472 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 4 Figure 1 Project Site Vicinity 473 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 5 Figure 2 Preliminary Site Plan 474 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 6 EXISTING CONDITIONS Roadway Network Table 1 describes the existing characteristics of the streets that would be used as primary routes to and from the site. Roadway characteristics are described in terms of orientation, arterial classification, posted speed limits, number of lanes, street parking, pedestrian facilities, and bicycle facilities. The relationship of these roadways to the project site is shown in Figure 1. Table 1 Existing Roadway Network Summary – Project Site Vicinity Roadway Orientation Classification Speed Limit Number of Travel Lanes Street Parking Sidewalks Bicycle Facilities 51st Ave S N/S Local Residential 25 2 None None None 56th Ave S N/S Residential Collector 35 2 None East Side* None S 331st Street E/W Residential Collector 25 2 None None None *Between S 328th Street and S 329th Street Existing Traffic Volumes Existing weekday AM and PM peak hour traffic volumes at the four study intersections were based on counts collected by All Traffic Data and Traffic Count Consultants in 2018. Figure 3 illustrates the 2018 existing weekday AM and PM peak hour traffic volumes at the study intersections. The detailed peak hour turning movement count sheets are provided in Appendix A. 475 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 7 Figure 3 2018 Existing Weekday Peak Hour Traffic Volumes 476 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 8 Level of Service Weekday AM and PM peak hour LOS analyses were conducted at the following four study intersections: 1. 56th Avenue S / S 316th Street (all-way stop controlled) 2. 46th Place S / S 321st Street (two-way stop controlled) 3. 46th Place S / S 324th Street (two-way stop controlled) 4. 56th Avenue S / S 331st Street (all-way stop controlled) LOS generally refers to the degree of congestion on a roadway or intersection. It is a measure of vehicle operating speed, travel time, travel delays, and driving comfort. A letter scale from A to F generally describes intersection LOS. At signalized intersections, LOS A represents free-flow conditions (motorists experience little or no delays), and LOS F represents forced-flow conditions where motorists experience an average delay in excess of 80 seconds per vehicle. The LOS reported at stop-controlled intersections is based on the average control delay and can be reported for each controlled minor approach, controlled minor lane group, and controlled major- street movement (and for the overall intersection at all-way stop controlled intersections. Additional v/c ratio criteria apply to lane group or movement LOS only). Table 2 outlines the current HCM 6th Edition LOS criteria for signalized and stop-controlled intersections based on these methodologies. Table 2 LOS Criteria for Stop-Controlled Intersections1 STOP-CONTROLLED INTERSECTIONS LOS by Volume-to Capacity (V/C) Ratio2 Control Delay (sec/veh) £ 1.0 > 1.0 £ 10 A F > 10 to £ 15 B F > 15 to £ 25 C F > 25 to £ 35 D F > 35 to £ 50 E F > 50 F F 1 Source: Highway Capacity Manual (6th Edition), Transportation Research Board, 2016. 2 For approach-based and intersection-wide assessments at signals, LOS is defined solely by control delay. 3 For two-way stop controlled intersections, the LOS criteria apply to each lane on a given approach and to each approach on the minor street. LOS is not calculated for major-street approaches or for the intersection as a whole at two-way stop controlled intersections. For approach-based and intersection-wide assessments at all-way stop controlled intersections, LOS is solely defined by control delay. Level of service calculations for the study intersections were based on methodology and procedures outlined in the latest Highway Capacity Manual (6th Edition) using Synchro 10.3 traffic analysis software. The 2018 existing AM and PM peak hour LOS analysis results for the study intersections are summarized in Table 3. The 2018 existing LOS worksheets are included in Appendix B. 477 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 9 Table 3 2018 Existing AM and PM Peak Hour LOS Summary AM Peak Hour PM Peak Hour Study Intersection / Movement LOS 1 Delay (sec) 2 V/C3 LOS 1 Delay (sec) 2 V/C3 All-Way Stop Controlled Intersections 1. 56th Avenue S / S 316th Street A 8.6 0.30 A 9.7 0.37 4. 56th Avenue S / S 331st Street A 7.6 0.11 A 7.7 0.16 Two-Way Stop Controlled Intersections 2. 44th Avenue S / 46th Place S / S 321st Street Northbound Shared Left-Thru-Right F 91.7 0.62 F 130.0 0.89 Eastbound Left-Turn A 8.5 0.09 A 9.1 0.08 Westbound Left-Turn A 9.7 0.01 A 8.7 0.01 Southbound Shared Left-Thru E 41.9 0.11 D 34.8 0.04 Southbound Right B 11.4 0.11 B 13.8 0.17 3. 46th Place S / S 324th Street Westbound Shared Left-Right A 8.8 0.02 A 9.3 0.02 Southbound Left-Turn A 7.3 0.01 A 7.5 0.01 1. LOS = Level of Service 2. Delay refers to average control delay expressed in seconds per vehicle. 3. Reported v/c ratio for AWSC is for worst movement. As shown in Table 3, both all-way stop-controlled study intersections and all individual movements at the two-way stop-controlled study intersections currently operate at LOS B or better during both the weekday AM and PM peak hours with two exception. The northbound and southbound approaches at the 46th Place S/S 321st Street intersection (study intersection #2) currently include movements that operates at LOS E/F during both the weekday AM and PM peak hours. The currently adopted level of service standards from the City of AuburnÊs Comprehensive Transportation Plan for stop-controlled intersections is detailed below: Two-Way and All-Way Stop Controlled Intersection LOS: The level-of-service standard for two-way stop controlled and all-way stop controlled intersections, is „D‰. If LOS falls below the standard, analysis and mitigation may be required in a manner commensurate with the associated impacts. This may include, among other requirements, conducting a traffic signal warrant analysis and installing or financing a signal or roundabout. Collision History Historic collisions at the study intersections were analyzed for the three-year period from 2015 to 2017. Collision data was provided by the City of Auburn. Summaries of the total and yearly average collisions during this period are provided in Table 4. Summaries of collisions by type over the three-year period are provided in Table 5. 478 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 10 Table 4 Collision Data Summary, January 1, 2015 to December 31, 2017 Intersection 2015 2016 2017 Three-Year Total Collisions Average Annual Collisions 56th Ave S / S 316th St 1 1 3 5 1.67 46th Pl S / S 321st St 0 0 0 0 0.00 46th Pl S / S 324th St 0 0 0 0 0.00 56th Ave S / S 331st St 0 0 0 0 0.00 Sources: City of Auburn Collision Records, and WSDOT Crash Data. Table 5 Collision Data Summary By Type, January 1, 2015 to December 31, 2017 Collision Type Location 3-Year Total Collisions Average Annual Collision Rate Approach Turn Sideswipe Right Angle Rear-end Parked Veh / Fixed Other 56th Ave S / S 316th St 5 1.67 0 0 2 2 1 0 46th Pl S / S 321st St 0 0.00 0 0 0 0 0 0 46th Pl S / S 324th St 0 0.00 0 0 0 0 0 0 56th Ave S / S 331st St 0 0.00 0 0 0 0 0 0 Source: City of Auburn Collision Records. The City of Auburn collects and reviews collision data to identify intersection and road locations where potential hazards exist. Potential safety problems are identified using the Safety Priority Index System (SPIS) methodology. The SPIS score for a location considers three years of data and considers frequency, collision rate, and severity. Based on CityÊs 2015-2017 SPIS, there were 104 intersections included and the SPIS scores ranged from 19.66 to 85.84 with a Citywide average of 49.15. None of the four study intersections were included on this list. 479 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 11 FUTURE TRAFFIC CONDITIONS AND PROJECT IMPACTS Planned Transportation Improvements This section documents the known transportation improvements planned by the City in the study area. Planned transportation improvement projects identified in the City of AuburnÊs adopted 2022 - 2027 Transportation Improvement Program (TIP) are included below. · TIP #R-9 – 46th Place S Realignment Description: The project will improve the 46th Place S intersection with S 321st Street. One of the options being considered is the realignment of 46th Place S approximately 350 feet to the east the existing alignment. This will create two T-intersections (44th Avenue S and 46th Place S) in place of the existing four-leg intersection. Other improvements are also being evaluated. The project will improve safety and traffic operations at the intersections. The TIP identifies full funding for the project by 2027 via traffic impact fees. · TIP #N-8 – Evergreen Heights Elementary Sidewalks Description: The project will construct a new sidewalk along the north side of S 316th Street between the end of the existing sidewalk at 56th Avenue S and 51st Avenue S to the west (approximately 1,250 feet). The project will also construct curb and gutter, storm improvements, and street lighting. Project Trip Generation The trip generation estimate for the proposed project was based on the methodology included in the Institute of Transportation Engineers (ITE) Trip Generation Manual, 10th edition for Land Use Code (LUC) 210 (Single-Family Detached Housing). Table 6 summarizes the resulting net new weekday daily, AM peak hour, and PM peak hour trip generation estimates for 43 net new single-family homes (44 proposed single-family homes less 1 existing single-family home to be removed). Detailed trip generation calculations are included in Appendix C. Table 6 Trip Generation Summary Net New Trips Generated Time Period In Out Total Weekday Daily 240 240 480 Weekday AM Peak Hour 9 26 35 Weekday PM Peak Hour 28 17 45 480 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 12 As shown in Table 6, the proposed Carbon Trails Residential project is estimated to generate 480 net new weekday daily trips, with 35 net new trips occurring during the weekday AM peak hour (9 entering, 26 exiting), and 45 net new trips occurring during the weekday PM peak hour (28 entering, 17 exiting). Project Trip Distribution and Assignment The distribution of the new project trips generated by the proposed Carbon Trails Residential development was based on anticipated travel patterns, other approved projects in the study area (Polygon Auburn Assemblage), and coordination with City of Auburn staff as part of the Traffic Scoping for the project. The following Table 7 summarizes the resulting general trip distribution patterns. The distribution of project trips is shown graphically in Figure 4. Table 7 Project Trip Distribution Route (Direction) Trip Distribution S 320th Street (west) 40% Military Road S (north) 5% 51st Avenue S (north) 5% 15th Street NW (east) 20% Mountain View Drive SW (east) 25% Peasley Canyon Way S (south) 5% TOTAL 100% Based on the trip distribution percentages, the net new weekday AM and PM peak hour project trips were assigned through the study intersections. The resulting assignment of the net new AM and PM peak hour project trips through the study intersections is shown in Figure 5. 481 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 13 Figure 4 Project Trip Distribution 482 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 14 Figure 5 Peak Hour Project Trip Assignment 483 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 15 Future Traffic Volumes Year 2023 Without-Project peak hour traffic volumes were estimated by applying a 2 percent annual background growth rate to the existing volumes. The 2 percent annual growth rate was determined to be appropriate based on conversations with the City during the scoping process. In addition to the background growth rate, traffic from the Huntington Woods Plat pipeline project was included in the future without-project peak hour traffic volume estimates. The resulting future 2023 without-project AM and PM peak hour traffic volumes are shown in Figure 6. The 2023 With-Project traffic volumes were determined by adding the trip assignment from the proposed development (shown in Figure 5) to the future 2023 Without-Project traffic volumes. The resulting future 2023 With-Project AM and PM peak hour traffic volumes at the study intersections are shown in Figure 7. It should be noted that the future With-Project traffic volumes account for expected changes in existing travel patterns associated with the completion of S 328th Street between 51st Avenue S and 56th Avenue S. 484 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 16 Figure 6 2023 Without Project Weekday Peak Hour Traffic Volumes 485 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 17 Figure 7 2023 With Project Weekday Peak Hour Traffic Volumes 486 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 18 Future Level of Service Future year 2023 Level of Service (LOS) analyses were conducted at the four study intersections for weekday AM and PM peak hour Without-Project and With-Project conditions. The 2023 weekday AM and PM peak hour LOS results at the study intersections without and with the proposed project are summarized in Tables 8 and 9. The detailed LOS worksheets are included in Appendix B. Table 8 Year 2023 AM Peak Hour LOS Summary 2023 Without Project 2023 With Project Study Intersection / Movement LOS 1 Delay (sec) 2 V/C3 LOS 1 Delay (sec) 2 V/C3 All-Way Stop Controlled Intersections 1. 56th Avenue S / S 316th Street A 9.0 0.33 A 9.0 0.33 4. 56th Avenue S / S 331st Street A 7.7 0.12 A 7.7 0.12 Two-Way Stop Controlled Intersections 2. 44th Avenue S / 46th Place S / S 321st Street Northbound Shared Left-Thru-Right F 206.9 0.97 F 314.8 1.27 Eastbound Left-Turn A 8.8 0.11 A 8.8 0.11 Westbound Left-Turn B 10.1 0.01 B 10.1 0.01 Southbound Shared Left-Thru F 58.4 0.16 F 58.4 0.16 Southbound Right B 12.0 0.13 B 12.0 0.13 3. 46th Place S / S 324th Street Westbound Shared Left-Right A 8.9 0.03 A 8.9 0.05 Southbound Left-Turn A 7.3 0.01 A 7.3 0.01 1. LOS = Level of Service 2. Delay refers to average control delay expressed in seconds per vehicle. 3. Reported v/c ratio for AWSC is for worst movement. Table 9 Year 2023 PM Peak Hour LOS Summary 2023 Without Project 2023 With Project Study Intersection / Movement LOS 1 Delay (sec) 2 V/C3 LOS 1 Delay (sec) 2 V/C3 All-Way Stop Controlled Intersections 1. 56th Avenue S / S 316th Street B 10.3 0.42 B 10.4 0.43 4. 56th Avenue S / S 331st Street A 7.8 0.18 A 7.8 0.19 Two-Way Stop Controlled Intersections 2. 44th Avenue S / 46th Place S / S 321st Street Northbound Shared Left-Thru-Right F 325.8 1.38 F 392.9 1.54 Eastbound Left-Turn A 9.4 0.09 A 9.4 0.09 Westbound Left-Turn A 8.9 0.01 A 9.0 0.01 Southbound Shared Left-Thru E 45.6 0.06 E 47.0 0.06 Southbound Right C 15.1 0.21 C 15.1 0.21 3. 46th Place S / S 324th Street Westbound Shared Left-Right A 9.3 0.02 A 9.3 0.04 Southbound Left-Turn A 7.5 0.01 A 7.5 0.03 1. LOS = Level of Service 2. Delay refers to average control delay expressed in seconds per vehicle. 3. Reported v/c ratio for AWSC is for worst movement. 487 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 19 As shown in Tables 8 and 9, both all-way stop-controlled study intersections and all individual movements at the two-way stop-controlled study intersections are anticipated to operate at LOS B or better during both the weekday AM and PM peak hours in 2023 with the proposed project with two exceptions. The northbound and southbound stop controlled approaches at the 46th Place S/S 321st Street intersection (#3) are anticipated to include movements that operate at LOS E/F during both the weekday AM and PM peak hours without or with the proposed project. The currently adopted level of service standards from the City of AuburnÊs Comprehensive Transportation Plan for stop-controlled intersections is detailed below: Two-Way and All-Way Stop Controlled Intersection LOS: The level-of-service standard for two-way stop controlled and all-way stop controlled intersections, is „D‰. If LOS falls below the standard, analysis and mitigation may be required in a manner commensurate with the associated impacts. This may include, among other requirements, conducting a traffic signal warrant analysis and installing or financing a signal or roundabout. The City of Auburn has a planned improvement at the 46th Place S/S 321st Street intersection (TIP Project #R-9) that would improve safety and traffic operations. The planned improvement would include realigning 46th Place S approximately 350 feet to the east of the current location. This will create two T-intersections (44th Avenue S and 46th Place S) in place of the existing four-leg intersection. The 2023 weekday AM and PM peak hour LOS results with the proposed Carbon Trails project at the 44th Avenue S and 46th Place S intersections with S 321st Street with this planned improvement are shown below in Table 10. Table 10 Year 2023 Peak Hour LOS Summary – With City Planned Improvement AM Peak Hour PM Peak Hour Study Intersection / Movement LOS 1 Delay (sec) 2 V/C3 LOS 1 Delay (sec) 2 V/C3 Two-Way Stop Controlled Intersections 2a. 44th Avenue S / S 321st Street Eastbound Left-Turn A 9.0 0.11 A 9.9 0.10 Southbound Left-Turn F 56.1 0.15 E 45.6 0.06 Southbound Right-Turn B 12.8 0.15 C 17.0 0.24 2b. 46th Place S / S 321st Street Northbound Shared Left-Right E 42.6 0.46 F 56.8 0.66 Westbound Left-Turn B 10.1 0.01 A 9.0 0.01 1. LOS = Level of Service 2. Delay refers to average control delay expressed in seconds per vehicle. As shown in Table 10, with the future realigning of 46th Place S this would result in delays at the stop controlled northbound and southbound movements that are better than pre-project conditions. It should be noted that the transportation impact fees to be paid by the project will help fund the 46th Place S realignment project. The projectÊs proportionate share impact at the intersection is 1.5 percent or less during the weekday AM and PM peak hours. Site Access Analysis An analysis of the proposed site access locations of 51st Ave S/S 328th Street and 56th Ave S/S 328th Street was conducted for 2023 With Project AM and PM peak hour conditions. The analysis includes an assessment of peak hour LOS and sight distance. 488 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 20 Level of Service A future year 2023 With Project AM and PM peak hour level of service (LOS) analysis was conducted at the proposed site access locations of 51st Ave S/S 328th Street and 56th Ave S/S 328th Street based on the methodology and procedures outlined in the 6th Edition of the Highway Capacity Manual (HCM) using the Synchro 10.3 software program. The 2023 With Project AM and PM peak hour volumes at the site access locations used in the LOS analyses are shown in Figure 7. The weekday AM and PM peak hour LOS results at the site access locations for 2023 With Project conditions are summarized in Table 11. The LOS and queue worksheets are included in Appendix B. Table 11 Year 2023 Peak Hour Level of Service Summary at Site Access Locations AM Peak Hour PM Peak Hour Driveway Location and Movement LOS 1 Delay (sec) 2 V/C3 LOS 1 Delay (sec) 2 V/C3 A. 51st Avenue S / S 328th Street Westbound Shared Left-Right (exiting) A 8.6 0.07 A 8.6 0.03 Southbound Left-Turn (entering) A 7.3 0.02 A 7.3 0.02 B. 56th Avenue S / S 328th Street Northbound Left-Turn (entering) A 7.3 0.00 A 7.4 0.01 Eastbound Shared Left-Thru-Right (exiting) A 8.9 0.02 A 9.3 0.02 1. LOS = Level of Service 2. Delay refers to average control delay expressed in seconds per vehicle. 3. Reported v/c ratio for AWSC is for worst movement. As shown in Table 11, the results of the LOS analysis show that the entering and exiting movements right-turn at the proposed site access locations are anticipated to operate at LOS A during the weekday AM and PM peak hours. 489 of 628 Updated Transportation Impact Analysis Carbon Trails Residential TENW July 1, 2021 Page 21 MITIGATION Transportation mitigation required by the City of Auburn is payment of a transportation impact fee. The proposed Carbon Trails Residential development would include the development of up to 44 single family dwelling units on an existing site that currently includes one single family dwelling unit that would be removed as part of the proposed project. As of the date of this study, the adopted City of Auburn 2021 impact fee schedule identifies a non-downtown fee of $5,652.57 per single- family dwelling unit. The estimated transportation impact fee is $243,060.51 ($5,652.57 X 43 net single-family dwelling units). Impact fees will be assessed by the City at the time the applicant submits a complete application for a building permit. The amount of the impact fees will be adjusted to the fees in effect at the time of payment. 490 of 628 Updated Transportation Impact Analysis Carbon Trails Residential Appendix A Peak Hour Turning Movement Counts 491 of 628 Peak Hour:07:15 AM - 08:15 AM 46TH PL S 46TH PL SS 324TH ST (303) 216-2439 www.alltrafficdata.net Location:1 46TH PL S & S 324TH ST AM Tuesday, September 11, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk001014 0 5 78 54 19 12 4273 N S EW 068 04020 S 324TH ST46TH PL S46TH PL S139 0 00 N S EW 0000 0 0 Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 7:00 AM 12601000402817200 7:15 AM 1390200010021433410 7:30 AM 1270000014011737500 7:45 AM 117020004042839100 8:00 AM 113010001203930410 8:15 AM 0 0 0 0 0 9 0 0 8 21310 8:30 AM 0 1 0 0 0 11 0 1 10 27310 8:45 AM 0 2 0 0 0 9 0 0 19 35410 Count Total 0 9 0 0 0 73 0 13 113 2392650 Peak Hour 0 5 0 0 0 40 0 10 68 1391420 HV%PHF 0.79 0.75 0.61 5.3% 4.8% 5.1% 5.0%0.89 EB WB NB SB All 0001 0 0 4 3 1 0 24 N S EW 04 0200Heavy VehiclesInterval Start Time EB NB TotalWBSB 7:00 AM 1 0 0 1 7:15 AM 0 0 0 0 7:30 AM 0 1 1 2 7:45 AM 0 0 1 1 8:00 AM 2 0 2 4 8:15 AM 1 0 0 1 8:30 AM 0 1 0 1 8:45 AM 1 0 1 2 Count Total 5 2 5 12 Peak Hour 2 1 4 7 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 7:00 AM 0 0 0 0 7:15 AM 0 0 0 0 7:30 AM 0 0 0 0 7:45 AM 0 0 0 0 8:00 AM 0 0 0 0 8:15 AM 0 1 0 1 8:30 AM 0 0 0 0 8:45 AM 0 0 0 0 Count Total 0 1 0 1 Peak Hour 0 0 0 0 492 of 628 Peak Hour:07:00 AM - 08:00 AM 51ST AVE S 51ST AVE SS 328TH ST (303) 216-2439 www.alltrafficdata.net Location:2 51ST AVE S & S 328TH ST AM Tuesday, September 11, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk0000 0 1 7 5 1 0 58 N S EW 07 0500 S 328TH ST51ST AVE S51ST AVE S13 0 00 N S EW 0000 0 0 Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 7:00 AM 130000020002000 7:15 AM 110000000000000 7:30 AM 120100020069000 7:45 AM 40000010012000 8:00 AM 60000000000000 8:15 AM 0 1 0 0 0 0 0 0 0 1000 8:30 AM 0 1 0 0 0 0 0 0 0 1000 8:45 AM 0 0 0 0 0 1 0 0 3 4000 Count Total 0 3 0 0 0 6 0 0 10 19000 Peak Hour 0 1 0 0 0 5 0 0 7 13000 HV%PHF 0.25 0.63 0.29 0.0% 0.0% 0.0% 0.0%0.36 EB WB NB SB All 0000 0 0 0 0 0 0 00 N S EW 00 0000Heavy VehiclesInterval Start Time EB NB TotalWBSB 7:00 AM 0 0 0 0 7:15 AM 0 0 0 0 7:30 AM 0 0 0 0 7:45 AM 0 0 0 0 8:00 AM 0 0 0 0 8:15 AM 0 0 0 0 8:30 AM 0 0 0 0 8:45 AM 0 0 0 0 Count Total 0 0 0 0 Peak Hour 0 0 0 0 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 7:00 AM 0 0 0 0 7:15 AM 0 0 0 0 7:30 AM 0 0 0 0 7:45 AM 0 0 0 0 8:00 AM 0 0 0 0 8:15 AM 0 0 0 0 8:30 AM 0 0 0 0 8:45 AM 0 0 0 0 Count Total 0 0 0 0 Peak Hour 0 0 0 0 493 of 628 Peak Hour:08:00 AM - 09:00 AM 56TH AVE S 56TH AVE SS 328TH ST (303) 216-2439 www.alltrafficdata.net Location:3 56TH AVE S & S 328TH ST AM Tuesday, September 11, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk0006 0 17 26 37 24 6 3643 N S EW 126 03150 S 328TH ST56TH AVE S56TH AVE S86 0 00 N S EW 0000 0 0 Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 7:00 AM 5701000500310100 7:15 AM 6703000400412100 7:30 AM 83080102001122000 7:45 AM 7301000200513140 8:00 AM 8601000800920110 8:15 AM 0 5 0 0 0 11 0 0 9 28120 8:30 AM 1 5 0 0 0 5 0 0 0 12010 8:45 AM 0 6 0 0 0 7 0 0 8 26410 Count Total 1 30 0 1 0 44 0 0 49 143990 Peak Hour 1 17 0 0 0 31 0 0 26 86650 HV%PHF 0.60 0.69 0.72 4.2% 8.3% 7.7% 7.0%0.77 EB WB NB SB All 0001 0 0 2 3 1 1 32 N S EW 02 0210Heavy VehiclesInterval Start Time EB NB TotalWBSB 7:00 AM 0 0 0 0 7:15 AM 0 0 0 0 7:30 AM 0 0 0 0 7:45 AM 1 0 0 1 8:00 AM 0 1 2 3 8:15 AM 2 0 0 2 8:30 AM 1 0 0 1 8:45 AM 0 0 0 0 Count Total 4 1 2 7 Peak Hour 3 1 2 6 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 7:00 AM 0 0 0 0 7:15 AM 0 0 0 0 7:30 AM 0 0 0 0 7:45 AM 0 0 0 0 8:00 AM 0 0 0 0 8:15 AM 0 0 0 0 8:30 AM 0 0 0 0 8:45 AM 0 0 0 0 Count Total 0 0 0 0 Peak Hour 0 0 0 0 494 of 628 Peak Hour:07:30 AM - 08:30 AM 56TH AVE SS 331ST STS 331ST ST (303) 216-2439 www.alltrafficdata.net Location:4 56TH AVE S & S 331ST ST AM Tuesday, September 11, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk1603829 21 0 0 79 4 54 33 50 11783 37 N S EW 0 0 0S 331ST ST S 331ST ST 56TH AVE S187 0 00N S EW 000 0 00Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 7:00 AM 156001000603026052 7:15 AM 170001200507028040 7:30 AM 1870125003010051039 7:45 AM 169032800507051071 8:00 AM 163001400709040082 8:15 AM 0 0 12 0 0 6 0 12 0 450114 8:30 AM 0 2 12 0 0 8 0 5 0 33051 8:45 AM 0 5 20 0 0 5 0 7 0 45035 Count Total 0 11 133 0 0 45 0 60 0 31904624 Peak Hour 0 4 79 0 0 21 0 38 0 18702916 HV%PHF 0.67 0.74 0.71 4.8% 4.0% 3.7% 4.3%0.92 EB WB NB SB All 1012 0 0 0 3 1 2 3 2 44 1 N S EW 0 0 0Heavy VehiclesInterval Start Time EB NB TotalWBSB 7:00 AM 0 1 0 1 7:15 AM 0 0 0 0 7:30 AM 0 0 0 0 7:45 AM 2 0 0 2 8:00 AM 2 0 2 4 8:15 AM 0 2 0 2 8:30 AM 1 1 0 2 8:45 AM 1 0 0 1 Count Total 6 4 2 12 Peak Hour 4 2 2 8 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 7:00 AM 0 0 0 0 7:15 AM 0 0 0 0 7:30 AM 0 0 0 0 7:45 AM 0 0 0 0 8:00 AM 0 0 0 0 8:15 AM 0 0 0 0 8:30 AM 0 0 0 0 8:45 AM 0 0 0 0 Count Total 0 0 0 0 Peak Hour 0 0 0 0 495 of 628 Peak Hour:07:15 AM - 08:15 AM 51ST AVE S46TH PL S46TH PL S (303) 216-2439 www.alltrafficdata.net Location:5 51ST AVE S & 46TH PL S AM Tuesday, September 11, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk30124 32 0 0 67 2 15 6 36 7969 35 N S EW 0 0 046TH PL S 46TH PL S 51ST AVE S120 0 00N S EW 000 0 00Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 7:00 AM 117011100700020010 7:15 AM 120001200702025022 7:30 AM 117022100808040010 7:45 AM 105002400700032001 8:00 AM 1070010001002023010 8:15 AM 0 0 11 0 0 10 0 1 0 22000 8:30 AM 0 1 13 0 0 10 0 1 0 28021 8:45 AM 0 1 18 0 0 8 0 5 0 34011 Count Total 0 5 120 0 0 67 0 19 0 224085 Peak Hour 0 2 67 0 0 32 0 12 0 120043 HV%PHF 0.72 0.82 0.47 5.8% 2.8% 0.0% 4.2%0.75 EB WB NB SB All 0000 1 0 0 4 0 0 0 1 44 1 N S EW 0 0 0Heavy VehiclesInterval Start Time EB NB TotalWBSB 7:00 AM 0 0 0 0 7:15 AM 0 0 0 0 7:30 AM 1 0 0 1 7:45 AM 1 0 0 1 8:00 AM 2 1 0 3 8:15 AM 1 1 0 2 8:30 AM 1 1 0 2 8:45 AM 1 0 0 1 Count Total 7 3 0 10 Peak Hour 4 1 0 5 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 7:00 AM 0 0 0 0 7:15 AM 0 0 0 0 7:30 AM 0 0 0 0 7:45 AM 0 0 0 0 8:00 AM 0 0 0 0 8:15 AM 0 0 0 0 8:30 AM 0 0 0 0 8:45 AM 0 0 0 0 Count Total 0 0 0 0 Peak Hour 0 0 0 0 496 of 628 Peak Hour:07:00 AM - 08:00 AM 56TH AVE S 56TH AVE SS 316TH STS 316TH ST (303) 216-2439 www.alltrafficdata.net Location:1 56TH AVE S & S 316TH ST AM Thursday, October 4, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk2037 98 3 10 240 3 5 12 109 263 3813 253 117 N S EW 1 0 0172190S 316TH ST S 316TH ST56TH AVE S56TH AVE S405 0 102N S EW 0100 0 0 20Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 7:00 AM 405015901260400001002160 7:15 AM 392016501230110201061470 7:30 AM 373016411190710101023022 7:45 AM 35300520030050000974240 8:00 AM 37903490019072000873220 8:15 AM 0 6 33 0 3 15 0 4 4 0 1 0 874782 8:30 AM 0 3 37 0 1 19 0 3 2 0 1 1 823822 8:45 AM 0 3 35 0 4 28 0 4 4 0 9 2 12331795 Count Total 0 18 394 1 11 179 0 35 14 0 14 3 78423414011 Peak Hour 0 3 240 1 3 98 0 17 2 0 3 0 405107192 HV%PHF 0.93 0.85 0.95 0.42 1.6% 3.7% 5.3% 0.0% 2.5%0.96 EB WB NB SB All 0001 2 1 0 4 0 0 1 4 6 21 4 2 N S EW 0 0 00020Heavy VehiclesInterval Start Time EB NB TotalWBSB 7:00 AM 2 1 2 0 5 7:15 AM 1 0 1 0 2 7:30 AM 0 0 1 0 1 7:45 AM 1 1 0 0 2 8:00 AM 0 2 0 0 2 8:15 AM 0 0 1 0 1 8:30 AM 0 0 0 1 1 8:45 AM 3 2 12 3 20 Count Total 7 6 17 4 34 Peak Hour 4 2 4 0 10 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 7:00 AM 0 0 0 0 0 7:15 AM 0 0 0 0 0 7:30 AM 0 0 1 0 1 7:45 AM 2 0 0 0 2 8:00 AM 0 0 0 0 0 8:15 AM 0 0 0 1 1 8:30 AM 0 0 1 0 1 8:45 AM 0 1 0 1 2 Count Total 2 1 2 2 7 Peak Hour 2 0 1 0 3 497 of 628 Peak Hour:04:00 PM - 05:00 PM 46TH PL S 46TH PL SS 324TH ST (303) 216-2439 www.alltrafficdata.net Location:1 46TH PL S & S 324TH ST PM Tuesday, September 11, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk001511 0 4 96 89 15 16 7985 N S EW 081 07810 S 324TH ST46TH PL S46TH PL S190 0 30 N S EW 0300 0 0 Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 4:00 PM 1900100024042354200 4:15 PM 1730100024041647200 4:30 PM 1790100018021844500 4:45 PM 1810100012052445210 5:00 PM 1690000014021737310 5:15 PM 0 0 0 0 0 23 1 4 20 53410 5:30 PM 0 2 0 0 0 12 0 6 24 46110 5:45 PM 0 2 0 0 0 12 0 4 12 33210 Count Total 0 8 0 0 0 139 1 31 154 3592150 Peak Hour 0 4 0 0 0 78 0 15 81 1901110 HV%PHF 0.63 0.82 0.83 13.3% 2.5% 4.2% 4.2%0.88 EB WB NB SB All 0011 0 1 4 3 2 1 24 N S EW 03 0200Heavy VehiclesInterval Start Time EB NB TotalWBSB 4:00 PM 1 2 2 5 4:15 PM 1 0 1 2 4:30 PM 0 0 1 1 4:45 PM 0 0 0 0 5:00 PM 0 0 0 0 5:15 PM 0 0 0 0 5:30 PM 0 0 1 1 5:45 PM 0 0 0 0 Count Total 2 2 5 9 Peak Hour 2 2 4 8 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 4:00 PM 0 0 0 0 4:15 PM 0 0 0 0 4:30 PM 0 3 0 3 4:45 PM 0 0 0 0 5:00 PM 0 0 0 0 5:15 PM 0 0 0 0 5:30 PM 0 0 0 0 5:45 PM 0 0 0 0 Count Total 0 3 0 3 Peak Hour 0 3 0 3 498 of 628 Peak Hour:04:30 PM - 05:30 PM 51ST AVE S 51ST AVE SS 328TH ST (303) 216-2439 www.alltrafficdata.net Location:2 51ST AVE S & S 328TH ST PM Tuesday, September 11, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk0000 0 1 5 14 1 0 146 N S EW 05 01400 S 328TH ST51ST AVE S51ST AVE S20 0 42 N S EW 2202 0 0 Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 4:00 PM 130000010012000 4:15 PM 160000010012000 4:30 PM 200000050005000 4:45 PM 180000020024000 5:00 PM 170000040015000 5:15 PM 0 1 0 0 0 3 0 0 2 6000 5:30 PM 0 0 0 0 0 3 0 0 0 3000 5:45 PM 0 0 0 0 0 2 0 0 1 3000 Count Total 0 1 0 0 0 21 0 0 8 30000 Peak Hour 0 1 0 0 0 14 0 0 5 20000 HV%PHF 0.25 0.70 0.63 0.0% 14.3% 0.0% 10.0%0.83 EB WB NB SB All 0000 0 0 0 2 0 0 20 N S EW 00 0200Heavy VehiclesInterval Start Time EB NB TotalWBSB 4:00 PM 0 0 0 0 4:15 PM 0 0 0 0 4:30 PM 0 0 0 0 4:45 PM 0 0 0 0 5:00 PM 2 0 0 2 5:15 PM 0 0 0 0 5:30 PM 0 0 0 0 5:45 PM 0 0 0 0 Count Total 2 0 0 2 Peak Hour 2 0 0 2 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 4:00 PM 0 0 0 0 4:15 PM 0 0 0 0 4:30 PM 0 0 0 0 4:45 PM 2 4 0 6 5:00 PM 0 0 0 0 5:15 PM 0 0 0 0 5:30 PM 0 0 0 0 5:45 PM 0 0 0 0 Count Total 2 4 0 6 Peak Hour 2 4 0 6 499 of 628 Peak Hour:05:00 PM - 06:00 PM 56TH AVE S 56TH AVE SS 328TH ST (303) 216-2439 www.alltrafficdata.net Location:3 56TH AVE S & S 328TH ST PM Tuesday, September 11, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk0074 0 2 38 49 6 17 5533 N S EW 031 045100 S 328TH ST56TH AVE S56TH AVE S99 0 10 N S EW 0100 0 0 Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 4:00 PM 880500013021136230 4:15 PM 8501000800519050 4:30 PM 9100000801517030 4:45 PM 9302000402416220 5:00 PM 99000001902933030 5:15 PM 0 1 0 0 0 9 0 1 8 25330 5:30 PM 0 0 0 0 0 9 0 2 7 19010 5:45 PM 0 1 0 0 0 8 0 2 7 22130 Count Total 0 10 0 0 0 78 0 12 56 1878230 Peak Hour 0 2 0 0 0 45 0 7 31 994100 HV%PHF 0.38 0.63 0.86 0.0% 0.0% 0.0% 0.0%0.75 EB WB NB SB All 0000 0 0 0 0 0 0 00 N S EW 00 0000Heavy VehiclesInterval Start Time EB NB TotalWBSB 4:00 PM 0 0 0 0 4:15 PM 0 0 0 0 4:30 PM 0 0 0 0 4:45 PM 0 0 0 0 5:00 PM 0 0 0 0 5:15 PM 0 0 0 0 5:30 PM 0 0 0 0 5:45 PM 0 0 0 0 Count Total 0 0 0 0 Peak Hour 0 0 0 0 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 4:00 PM 0 0 0 0 4:15 PM 0 0 0 0 4:30 PM 0 0 0 0 4:45 PM 0 0 0 0 5:00 PM 0 1 0 1 5:15 PM 0 0 0 0 5:30 PM 0 0 0 0 5:45 PM 0 0 0 0 Count Total 0 1 0 1 Peak Hour 0 1 0 1 500 of 628 Peak Hour:04:00 PM - 05:00 PM 56TH AVE SS 331ST STS 331ST ST (303) 216-2439 www.alltrafficdata.net Location:4 56TH AVE S & S 331ST ST PM Tuesday, September 11, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk702541 83 0 0 77 7 32 48 124 10284 90 N S EW 0 0 0S 331ST ST S 331ST ST 56TH AVE S240 0 00N S EW 000 0 00Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 4:00 PM 240021900240100730144 4:15 PM 23602180022050600121 4:30 PM 2230120001905053080 4:45 PM 2220220001805054072 5:00 PM 23406140025080690142 5:15 PM 0 2 15 0 0 16 0 6 0 47080 5:30 PM 0 2 19 0 0 14 0 7 0 520100 5:45 PM 0 5 20 0 0 22 0 7 0 660102 Count Total 0 22 145 0 0 160 0 53 0 47408311 Peak Hour 0 7 77 0 0 83 0 25 0 2400417 HV%PHF 0.95 0.82 0.57 4.8% 1.6% 0.0% 2.5%0.82 EB WB NB SB All 0000 2 0 0 4 0 0 0 2 44 2 N S EW 0 0 0Heavy VehiclesInterval Start Time EB NB TotalWBSB 4:00 PM 2 2 0 4 4:15 PM 1 0 0 1 4:30 PM 1 0 0 1 4:45 PM 0 0 0 0 5:00 PM 0 1 0 1 5:15 PM 0 1 0 1 5:30 PM 1 0 0 1 5:45 PM 0 0 0 0 Count Total 5 4 0 9 Peak Hour 4 2 0 6 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 4:00 PM 0 0 0 0 4:15 PM 0 0 0 0 4:30 PM 0 0 0 0 4:45 PM 0 0 0 0 5:00 PM 0 0 0 0 5:15 PM 0 0 0 0 5:30 PM 0 0 0 0 5:45 PM 0 0 0 0 Count Total 0 0 0 0 Peak Hour 0 0 0 0 501 of 628 Peak Hour:04:00 PM - 05:00 PM 51ST AVE S46TH PL S46TH PL S (303) 216-2439 www.alltrafficdata.net Location:5 51ST AVE S & 46TH PL S PM Tuesday, September 11, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk20816 75 0 0 74 3 10 19 92 8378 78 N S EW 1 1 046TH PL S 46TH PL S 51ST AVE S180 1 20N S EW 021 0 00Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 4:00 PM 1801121002601052011 4:15 PM 1780015102201043031 4:30 PM 1670116001403040060 4:45 PM 1680122001303045060 5:00 PM 1720020002103050051 5:15 PM 0 1 11 0 0 15 0 1 0 32031 5:30 PM 0 2 22 0 0 9 0 0 0 41053 5:45 PM 0 1 18 0 0 22 0 3 0 49041 Count Total 1 7 145 1 0 142 0 15 0 3520338 Peak Hour 1 3 74 1 0 75 0 8 0 1800162 HV%PHF 0.85 0.85 0.83 3.8% 3.3% 0.0% 3.3%0.87 EB WB NB SB All 0001 2 0 0 3 0 0 1 3 33 2 N S EW 0 0 0Heavy VehiclesInterval Start Time EB NB TotalWBSB 4:00 PM 1 2 0 3 4:15 PM 1 0 0 1 4:30 PM 1 0 0 1 4:45 PM 0 1 0 1 5:00 PM 0 0 0 0 5:15 PM 0 1 0 1 5:30 PM 1 0 0 1 5:45 PM 0 0 0 0 Count Total 4 4 0 8 Peak Hour 3 3 0 6 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 4:00 PM 0 2 1 3 4:15 PM 0 0 0 0 4:30 PM 0 0 0 0 4:45 PM 0 0 0 0 5:00 PM 0 0 0 0 5:15 PM 0 0 0 0 5:30 PM 0 0 0 0 5:45 PM 0 0 0 0 Count Total 0 2 1 3 Peak Hour 0 2 1 3 502 of 628 Peak Hour:04:30 PM - 05:30 PM 56TH AVE S 56TH AVE SS 316TH STS 316TH ST (303) 216-2439 www.alltrafficdata.net Location:1 56TH AVE S & S 316TH ST PM Thursday, October 4, 2018Date and Start Time: All Vehicles Pedestrians/Bicycles in Crosswalk Traffic Counts - All Vehicles Heavy Vehicles Peak Hour Traffic Counts - Heavy Vehicles and Pedestrians/Bicycles in Crosswalk90186 248 24 17 220 1 35 11 278 252 4349 238 282 N S EW 0 0 8254140S 316TH ST S 316TH ST56TH AVE S56TH AVE S594 2 101N S EW 0100 2 0 01Interval Start Time RightLeftThru Total Eastbound Westbound Northbound Southbound U-Turn Rolling HourRightLeftThruU-Turn RightLeftThruU-Turn RightLeftThruU-Turn 4:00 PM 572014404490700501217211 4:15 PM 572004209670700231404132 4:30 PM 594016205650530301564512 4:45 PM 5710051095705101251556045 5:00 PM 576004303570800121215020 5:15 PM 0 0 64 0 7 69 0 7 0 0 2 1 1622172 5:30 PM 0 0 40 0 6 62 0 6 0 0 3 0 1339061 5:45 PM 0 0 64 0 8 57 0 14 0 0 0 0 16012041 Count Total 0 2 410 0 51 483 0 59 4 0 28 11 1,1484992814 Peak Hour 0 1 220 0 24 248 0 25 4 0 18 8 594176149 HV%PHF 0.89 0.90 0.77 0.40 2.9% 1.8% 2.3% 0.0% 2.2%0.92 EB WB NB SB All 0000 4 1 0 7 0 0 0 5 7 11 7 5 N S EW 0 0 01000Heavy VehiclesInterval Start Time EB NB TotalWBSB 4:00 PM 2 0 0 0 2 4:15 PM 0 1 1 0 2 4:30 PM 2 0 0 0 2 4:45 PM 2 0 1 0 3 5:00 PM 1 1 4 0 6 5:15 PM 2 0 0 0 2 5:30 PM 0 0 1 0 1 5:45 PM 1 1 1 0 3 Count Total 10 3 8 0 21 Peak Hour 7 1 5 0 13 Pedestrians/Bicycles on CrosswalkInterval Start Time EB NB TotalWBSB 4:00 PM 0 0 0 1 1 4:15 PM 0 0 0 0 0 4:30 PM 0 0 0 0 0 4:45 PM 0 0 1 2 3 5:00 PM 1 0 0 0 1 5:15 PM 0 0 0 0 0 5:30 PM 0 0 0 0 0 5:45 PM 0 0 0 0 0 Count Total 1 0 1 3 5 Peak Hour 1 0 1 2 4 503 of 628 Updated Transportation Impact Analysis Carbon Trails Residential Appendix B Level of Service (LOS) Calculations 504 of 628 Updated Transportation Impact Analysis Carbon Trails Residential 2018 Existing 505 of 628 Lanes, Volumes, Timings 1: 56th Avenue S & S 316th Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - AM Peak Hour Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)3 240 10 4 98 7 17 2 19 3 0 2 Future Volume (vph)3 240 10 4 98 7 17 2 19 3 0 2 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Link Speed (mph)25 25 35 25 Link Distance (ft)668 578 3975 233 Travel Time (s)18.2 15.8 77.4 6.4 Confl. Peds. (#/hr)2 2 1 1 2 1 1 2 Peak Hour Factor 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 Heavy Vehicles (%)0% 2% 0% 33% 2% 14% 0% 0% 11% 0% 0% 0% Shared Lane Traffic (%) Sign Control Stop Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 506 of 628 HCM 6th AWSC 1: 56th Avenue S & S 316th Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - AM Peak Hour Intersection Intersection Delay, s/veh 8.6 Intersection LOS A Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 3 240 10 4 98 7 17 2 19 3 0 2 Future Vol, veh/h 3 240 10 4 98 7 17 2 19 3 0 2 Peak Hour Factor 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 Heavy Vehicles, %0 2 0 33 2 14 0 0 11 0 0 0 Mvmt Flow 3 250 10 4 102 7 18 2 20 3 0 2 Number of Lanes 0 1 0 0 1 0 0 1 0 0 1 0 Approach EB WB NB SB Opposing Approach WB EB SB NB Opposing Lanes 1 1 1 1 Conflicting Approach Left SB NB EB WB Conflicting Lanes Left 1 1 1 1 Conflicting Approach Right NB SB WB EB Conflicting Lanes Right 1 1 1 1 HCM Control Delay 8.8 8.6 7.8 7.7 HCM LOS A A A A Lane NBLn1 EBLn1 WBLn1 SBLn1 Vol Left, %45% 1% 4% 60% Vol Thru, %5% 95% 90% 0% Vol Right, %50% 4% 6% 40% Sign Control Stop Stop Stop Stop Traffic Vol by Lane 38 253 109 5 LT Vol 17 3 4 3 Through Vol 2 240 98 0 RT Vol 19 10 7 2 Lane Flow Rate 40 264 114 5 Geometry Grp 1 1 1 1 Degree of Util (X)0.05 0.296 0.148 0.007 Departure Headway (Hd)4.534 4.043 4.708 4.67 Convergence, Y/N Yes Yes Yes Yes Cap 794 878 752 771 Service Time 2.535 2.117 2.797 2.672 HCM Lane V/C Ratio 0.05 0.301 0.152 0.006 HCM Control Delay 7.8 8.8 8.6 7.7 HCM Lane LOS A A A A HCM 95th-tile Q 0.2 1.2 0.5 0 507 of 628 Lanes, Volumes, Timings 2: 46th Place S/44th Avenue S & S 321st Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - AM Peak Hour Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)90 636 44 7 354 2 42 2 6 2 8 62 Future Volume (vph)90 636 44 7 354 2 42 2 6 2 8 62 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Storage Length (ft)0 0 0 0 0 0 0 50 Storage Lanes 0 0 0 0 0 0 0 1 Taper Length (ft)25 25 25 25 Link Speed (mph)35 35 35 25 Link Distance (ft)523 579 1356 280 Travel Time (s)10.2 11.3 26.4 7.6 Confl. Peds. (#/hr)2 2 2 2 Peak Hour Factor 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 Heavy Vehicles (%)4% 3% 2% 14% 1% 0% 0% 0% 17% 0% 0% 0% Shared Lane Traffic (%) Sign Control Free Free Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 508 of 628 HCM 6th TWSC 2: 46th Place S/44th Avenue S & S 321st Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - AM Peak Hour Intersection Int Delay, s/veh 5.2 Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 90 636 44 7 354 2 42 2 6 2 8 62 Future Vol, veh/h 90 636 44 7 354 2 42 2 6 2 8 62 Conflicting Peds, #/hr 2 0 0 0 0 2 0 0 0 2 0 2 Sign Control Free Free Free Free Free Free Stop Stop Stop Stop Stop Stop RT Channelized - - None - - None - - None - - Stop Storage Length - - - - - - - - - - - 50 Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 - Grade, % - 0 - - 0 - - 0 - - 0 - Peak Hour Factor 86 86 86 86 86 86 86 86 86 86 86 86 Heavy Vehicles, % 4 3 2 14 1 0 0 0 17 0 0 0 Mvmt Flow 105 740 51 8 412 2 49 2 7 2 9 72 Major/Minor Major1 Major2 Minor1 Minor2 Conflicting Flow All 416 0 0 791 0 0 1412 1408 768 1413 1432 417 Stage 1 - - - - - - 976 976 - 431 431 - Stage 2 - - - - - - 436 432 - 982 1001 - Critical Hdwy 4.14 - - 4.24 - - 7.1 6.5 6.37 7.1 6.5 6.2 Critical Hdwy Stg 1 - - - - - - 6.1 5.5 - 6.1 5.5 - Critical Hdwy Stg 2 - - - - - - 6.1 5.5 - 6.1 5.5 - Follow-up Hdwy 2.236 - - 2.326 - - 3.5 4 3.453 3.5 4 3.3 Pot Cap-1 Maneuver 1132 - - 779 - - 117 140 379 117 136 640 Stage 1 - - - - - - 305 332 - 607 586 - Stage 2 - - - - - - 603 586 - 302 323 - Platoon blocked, %- -- - Mov Cap-1 Maneuver 1130 - - 779 - - 84 115 378 97 112 638 Mov Cap-2 Maneuver - - - - - - 84 115 - 97 112 - Stage 1 - - - - - - 254 277 - 504 577 - Stage 2 - - - - - - 518 577 - 244 269 - Approach EB WB NB SB HCM Control Delay, s 1 0.2 91.7 15.6 HCM LOS F C Minor Lane/Major Mvmt NBLn1 EBL EBT EBR WBL WBT WBRSBLn1 SBLn2 Capacity (veh/h)94 1130 - - 779 - - 109 638 HCM Lane V/C Ratio 0.619 0.093 - - 0.01 - - 0.107 0.113 HCM Control Delay (s) 91.7 8.5 0 - 9.7 0 - 41.9 11.4 HCM Lane LOS F A A - A A - E B HCM 95th %tile Q(veh) 2.9 0.3 - - 0 - - 0.3 0.4 509 of 628 Lanes, Volumes, Timings 3: 46th Place S & S 324th Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - AM Peak Hour Lane Group WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Volume (vph)5 14 40 2 10 68 Future Volume (vph)5 14 40 2 10 68 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)25 35 35 Link Distance (ft)576 2425 1356 Travel Time (s)15.7 47.2 26.4 Peak Hour Factor 0.89 0.89 0.89 0.89 0.89 0.89 Heavy Vehicles (%)0% 7% 5% 0% 0% 6% Shared Lane Traffic (%) Sign Control Stop Free Free Intersection Summary Area Type:Other Control Type: Unsignalized 510 of 628 HCM 6th TWSC 3: 46th Place S & S 324th Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - AM Peak Hour Intersection Int Delay, s/veh 1.7 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h 5 14 40 2 10 68 Future Vol, veh/h 5 14 40 2 10 68 Conflicting Peds, #/hr 0 0 0 0 0 0 Sign Control Stop Stop Free Free Free Free RT Channelized - None - None - None Storage Length 0 - - - - - Veh in Median Storage, # 0 - 0 - - 0 Grade, % 0 - 0 - - 0 Peak Hour Factor 89 89 89 89 89 89 Heavy Vehicles, % 0 7 5 0 0 6 Mvmt Flow 6 16 45 2 11 76 Major/Minor Minor1 Major1 Major2 Conflicting Flow All 144 46 0 0 47 0 Stage 1 46 - - - - - Stage 2 98 - - - - - Critical Hdwy 6.4 6.27 - - 4.1 - Critical Hdwy Stg 1 5.4 - - - - - Critical Hdwy Stg 2 5.4 - - - - - Follow-up Hdwy 3.5 3.363 - - 2.2 - Pot Cap-1 Maneuver 853 1009 - - 1573 - Stage 1 982 - - - - - Stage 2 931 - - - - - Platoon blocked, % - -- Mov Cap-1 Maneuver 847 1009 - - 1573 - Mov Cap-2 Maneuver 847 - - - - - Stage 1 982 - - - - - Stage 2 924 - - - - - Approach WB NB SB HCM Control Delay, s 8.8 0 0.9 HCM LOS A Minor Lane/Major Mvmt NBT NBRWBLn1 SBL SBT Capacity (veh/h)- - 961 1573 - HCM Lane V/C Ratio - - 0.022 0.007 - HCM Control Delay (s) - - 8.8 7.3 0 HCM Lane LOS - - A A A HCM 95th %tile Q(veh) - - 0.1 0 - 511 of 628 Lanes, Volumes, Timings 4: S 331st Street & 56th Avenue S 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - AM Peak Hour Lane Group EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Volume (vph)4 79 21 29 38 16 Future Volume (vph)4 79 21 29 38 16 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)35 35 35 Link Distance (ft)505 495 1127 Travel Time (s)9.8 9.6 22.0 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles (%) 25% 4% 0% 7% 3% 6% Shared Lane Traffic (%) Sign Control Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 512 of 628 HCM 6th AWSC 4: S 331st Street & 56th Avenue S 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - AM Peak Hour Intersection Intersection Delay, s/veh 7.6 Intersection LOS A Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h 4 79 21 29 38 16 Future Vol, veh/h 4 79 21 29 38 16 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles, %25 4 0 7 3 6 Mvmt Flow 4 86 23 32 41 17 Number of Lanes 0 1 1 0 1 0 Approach EB WB SB Opposing Approach WB EB Opposing Lanes 1 1 0 Conflicting Approach Left SB WB Conflicting Lanes Left 1 0 1 Conflicting Approach Right SB EB Conflicting Lanes Right 0 1 1 HCM Control Delay 8.1 7 7.5 HCM LOS A A A Lane EBLn1 WBLn1 SBLn1 Vol Left, %5% 0% 70% Vol Thru, %95% 42% 0% Vol Right, %0% 58% 30% Sign Control Stop Stop Stop Traffic Vol by Lane 83 50 54 LT Vol 4 0 38 Through Vol 79 21 0 RT Vol 0 29 16 Lane Flow Rate 90 54 59 Geometry Grp 1 1 1 Degree of Util (X)0.112 0.056 0.068 Departure Headway (Hd)4.479 3.722 4.161 Convergence, Y/N Yes Yes Yes Cap 798 953 850 Service Time 2.518 1.782 2.238 HCM Lane V/C Ratio 0.113 0.057 0.069 HCM Control Delay 8.1 7 7.5 HCM Lane LOS A A A HCM 95th-tile Q 0.4 0.2 0.2 513 of 628 Lanes, Volumes, Timings 1: 56th Avenue S & S 316th Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - PM Peak Hour Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)1 220 17 24 248 6 25 4 14 18 8 9 Future Volume (vph)1 220 17 24 248 6 25 4 14 18 8 9 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Link Speed (mph)25 25 35 25 Link Distance (ft)668 578 3975 233 Travel Time (s)18.2 15.8 77.4 6.4 Confl. Peds. (#/hr)3 1 1 3 1 1 3 3 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles (%)0% 3% 0% 4% 2% 0% 4% 0% 0% 0% 0% 0% Shared Lane Traffic (%) Sign Control Stop Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 514 of 628 HCM 6th AWSC 1: 56th Avenue S & S 316th Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - PM Peak Hour Intersection Intersection Delay, s/veh 9.7 Intersection LOS A Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 1 220 17 24 248 6 25 4 14 18 8 9 Future Vol, veh/h 1 220 17 24 248 6 25 4 14 18 8 9 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles, %0 3 0 4 2 0 4 0 0 0 0 0 Mvmt Flow 1 239 18 26 270 7 27 4 15 20 9 10 Number of Lanes 0 1 0 0 1 0 0 1 0 0 1 0 Approach EB WB NB SB Opposing Approach WB EB SB NB Opposing Lanes 1 1 1 1 Conflicting Approach Left SB NB EB WB Conflicting Lanes Left 1 1 1 1 Conflicting Approach Right NB SB WB EB Conflicting Lanes Right 1 1 1 1 HCM Control Delay 9.5 10.2 8.6 8.5 HCM LOS A B A A Lane NBLn1 EBLn1 WBLn1 SBLn1 Vol Left, %58% 0% 9% 51% Vol Thru, %9% 92% 89% 23% Vol Right, %33% 7% 2% 26% Sign Control Stop Stop Stop Stop Traffic Vol by Lane 43 238 278 35 LT Vol 25 1 24 18 Through Vol 4 220 248 8 RT Vol 14 17 6 9 Lane Flow Rate 47 259 302 38 Geometry Grp 1 1 1 1 Degree of Util (X)0.067 0.316 0.375 0.055 Departure Headway (Hd)5.184 4.4 4.464 5.158 Convergence, Y/N Yes Yes Yes Yes Cap 689 817 807 692 Service Time 3.23 2.428 2.49 3.204 HCM Lane V/C Ratio 0.068 0.317 0.374 0.055 HCM Control Delay 8.6 9.5 10.2 8.5 HCM Lane LOS A A B A HCM 95th-tile Q 0.2 1.4 1.8 0.2 515 of 628 Lanes, Volumes, Timings 2: 46th Place S/44th Avenue S & S 321st Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - PM Peak Hour Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)69 464 94 6 556 9 72 9 10 1 4 80 Future Volume (vph)69 464 94 6 556 9 72 9 10 1 4 80 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Storage Length (ft)0 0 0 0 0 0 0 50 Storage Lanes 0 0 0 0 0 0 0 1 Taper Length (ft)25 25 25 25 Link Speed (mph)35 35 35 25 Link Distance (ft)523 579 1356 280 Travel Time (s)10.2 11.3 26.4 7.6 Confl. Peds. (#/hr)1 1 1 1 Peak Hour Factor 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 Heavy Vehicles (%)6% 1% 1% 0% 2% 0% 3% 0% 0% 0% 0% 3% Shared Lane Traffic (%) Sign Control Free Free Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 516 of 628 HCM 6th TWSC 2: 46th Place S/44th Avenue S & S 321st Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - PM Peak Hour Intersection Int Delay, s/veh 10 Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 69 464 94 6 556 9 72 9 10 1 4 80 Future Vol, veh/h 69 464 94 6 556 9 72 9 10 1 4 80 Conflicting Peds, #/hr 1 0 1 0 0 0 1 0 0 0 0 1 Sign Control Free Free Free Free Free Free Stop Stop Stop Stop Stop Stop RT Channelized - - None - - None - - None - - Stop Storage Length - - - - - - - - - - - 50 Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 - Grade, % - 0 - - 0 - - 0 - - 0 - Peak Hour Factor 93 93 93 93 93 93 93 93 93 93 93 93 Heavy Vehicles, % 6 1 1 0 2 0 3 0 0 0 0 3 Mvmt Flow 74 499 101 6 598 10 77 10 11 1 4 86 Major/Minor Major1 Major2 Minor1 Minor2 Conflicting Flow All 609 0 0 601 0 0 1317 1320 551 1324 1365 605 Stage 1 - - - - - - 699 699 - 616 616 - Stage 2 - - - - - - 618 621 - 708 749 - Critical Hdwy 4.16 - - 4.1 - - 7.13 6.5 6.2 7.1 6.5 6.23 Critical Hdwy Stg 1 - - - - - - 6.13 5.5 - 6.1 5.5 - Critical Hdwy Stg 2 - - - - - - 6.13 5.5 - 6.1 5.5 - Follow-up Hdwy 2.254 - - 2.2 - - 3.527 4 3.3 3.5 4 3.327 Pot Cap-1 Maneuver 950 - - 986 - - 134 158 538 134 149 496 Stage 1 - - - - - - 429 445 - 481 485 - Stage 2 - - - - - - 475 482 - 429 422 - Platoon blocked, %- -- - Mov Cap-1 Maneuver 949 - - 985 - - 97 138 537 112 130 495 Mov Cap-2 Maneuver - - - - - - 97 138 - 112 130 - Stage 1 - - - - - - 378 392 - 423 480 - Stage 2 - - - - - - 385 477 - 361 371 - Approach EB WB NB SB HCM Control Delay, s 1 0.1 130 15 HCM LOS F C Minor Lane/Major Mvmt NBLn1 EBL EBT EBR WBL WBT WBRSBLn1 SBLn2 Capacity (veh/h)110 949 - - 985 - - 126 495 HCM Lane V/C Ratio 0.89 0.078 - - 0.007 - - 0.043 0.174 HCM Control Delay (s) 130 9.1 0 - 8.7 0 - 34.8 13.8 HCM Lane LOS F A A - A A - D B HCM 95th %tile Q(veh) 5.3 0.3 - - 0 - - 0.1 0.6 517 of 628 Lanes, Volumes, Timings 3: 46th Place S & S 324th Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - PM Peak Hour Lane Group WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Volume (vph)4 11 78 1 15 81 Future Volume (vph)4 11 78 1 15 81 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)25 35 35 Link Distance (ft)576 2425 1356 Travel Time (s)15.7 47.2 26.4 Confl. Peds. (#/hr)3 3 3 3 Peak Hour Factor 0.88 0.88 0.88 0.88 0.88 0.88 Heavy Vehicles (%) 25% 9% 3% 0% 7% 4% Shared Lane Traffic (%) Sign Control Stop Free Free Intersection Summary Area Type:Other Control Type: Unsignalized 518 of 628 HCM 6th TWSC 3: 46th Place S & S 324th Street 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - PM Peak Hour Intersection Int Delay, s/veh 1.3 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h 4 11 78 1 15 81 Future Vol, veh/h 4 11 78 1 15 81 Conflicting Peds, #/hr 3 3 0 3 3 0 Sign Control Stop Stop Free Free Free Free RT Channelized - None - None - None Storage Length 0 - - - - - Veh in Median Storage, # 0 - 0 - - 0 Grade, % 0 - 0 - - 0 Peak Hour Factor 88 88 88 88 88 88 Heavy Vehicles, % 25 9 3 0 7 4 Mvmt Flow 5 13 89 1 17 92 Major/Minor Minor1 Major1 Major2 Conflicting Flow All 222 96 0 0 93 0 Stage 1 93 - - - - - Stage 2 129 - - - - - Critical Hdwy 6.65 6.29 - - 4.17 - Critical Hdwy Stg 1 5.65 - - - - - Critical Hdwy Stg 2 5.65 - - - - - Follow-up Hdwy 3.725 3.381 - - 2.263 - Pot Cap-1 Maneuver 718 942 - - 1471 - Stage 1 876 - - - - - Stage 2 843 - - - - - Platoon blocked, % - -- Mov Cap-1 Maneuver 705 937 - - 1467 - Mov Cap-2 Maneuver 705 - - - - - Stage 1 873 - - - - - Stage 2 830 - - - - - Approach WB NB SB HCM Control Delay, s 9.3 0 1.2 HCM LOS A Minor Lane/Major Mvmt NBT NBRWBLn1 SBL SBT Capacity (veh/h)- - 861 1467 - HCM Lane V/C Ratio - - 0.02 0.012 - HCM Control Delay (s) - - 9.3 7.5 0 HCM Lane LOS - - A A A HCM 95th %tile Q(veh) - - 0.1 0 - 519 of 628 Lanes, Volumes, Timings 4: S 331st Street & 56th Avenue S 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - PM Peak Hour Lane Group EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Volume (vph)7 77 83 41 25 7 Future Volume (vph)7 77 83 41 25 7 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)35 35 35 Link Distance (ft)505 495 1127 Travel Time (s)9.8 9.6 22.0 Peak Hour Factor 0.82 0.82 0.82 0.82 0.82 0.82 Heavy Vehicles (%)0% 5% 2% 0% 0% 0% Shared Lane Traffic (%) Sign Control Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 520 of 628 HCM 6th AWSC 4: S 331st Street & 56th Avenue S 01/15/2019 Carbon Trails Residential Synchro 10 Report 2018 Existing - PM Peak Hour Intersection Intersection Delay, s/veh 7.7 Intersection LOS A Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h 7 77 83 41 25 7 Future Vol, veh/h 7 77 83 41 25 7 Peak Hour Factor 0.82 0.82 0.82 0.82 0.82 0.82 Heavy Vehicles, %0 5 2 0 0 0 Mvmt Flow 9 94 101 50 30 9 Number of Lanes 0 1 1 0 1 0 Approach EB WB SB Opposing Approach WB EB Opposing Lanes 1 1 0 Conflicting Approach Left SB WB Conflicting Lanes Left 1 0 1 Conflicting Approach Right SB EB Conflicting Lanes Right 0 1 1 HCM Control Delay 7.7 7.7 7.7 HCM LOS A A A Lane EBLn1 WBLn1 SBLn1 Vol Left, %8% 0% 78% Vol Thru, %92% 67% 0% Vol Right, %0% 33% 22% Sign Control Stop Stop Stop Traffic Vol by Lane 84 124 32 LT Vol 7 0 25 Through Vol 77 83 0 RT Vol 0 41 7 Lane Flow Rate 102 151 39 Geometry Grp 1 1 1 Degree of Util (X)0.117 0.163 0.048 Departure Headway (Hd)4.099 3.881 4.459 Convergence, Y/N Yes Yes Yes Cap 869 918 808 Service Time 2.15 1.93 2.459 HCM Lane V/C Ratio 0.117 0.164 0.048 HCM Control Delay 7.7 7.7 7.7 HCM Lane LOS A A A HCM 95th-tile Q 0.4 0.6 0.2 521 of 628 Updated Transportation Impact Analysis Carbon Trails Residential 2023 Without Project 522 of 628 Lanes, Volumes, Timings 1: 56th Avenue S & S 316th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - AM Peak Hour Page 1 Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)3 265 11 4 109 8 19 2 21 3 0 2 Future Volume (vph)3 265 11 4 109 8 19 2 21 3 0 2 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Link Speed (mph)25 25 35 25 Link Distance (ft)668 578 3975 233 Travel Time (s)18.2 15.8 77.4 6.4 Confl. Peds. (#/hr)2 2 1 1 2 1 1 2 Peak Hour Factor 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 Heavy Vehicles (%)0% 2% 0% 33% 2% 14% 0% 0% 11% 0% 0% 0% Shared Lane Traffic (%) Sign Control Stop Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 523 of 628 HCM 6th AWSC 1: 56th Avenue S & S 316th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - AM Peak Hour Page 2 Intersection Intersection Delay, s/veh 9 Intersection LOS A Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 3 265 11 4 109 8 19 2 21 3 0 2 Future Vol, veh/h 3 265 11 4 109 8 19 2 21 3 0 2 Peak Hour Factor 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 Heavy Vehicles, % 0 2 0 33 2 14 0 0 11 0 0 0 Mvmt Flow 3 276 11 4 114 8 20 2 22 3 0 2 Number of Lanes 0 1 0 0 1 0 0 1 0 0 1 0 Approach EB WB NB SB Opposing Approach WB EB SB NB Opposing Lanes 1 1 1 1 Conflicting Approach Left SB NB EB WB Conflicting Lanes Left 1 1 1 1 Conflicting Approach Right NB SB WB EB Conflicting Lanes Right 1 1 1 1 HCM Control Delay 9.2 8.8 7.9 7.8 HCM LOS A A A A Lane NBLn1 EBLn1 WBLn1 SBLn1 Vol Left, %45% 1% 3% 60% Vol Thru, %5% 95% 90% 0% Vol Right, % 50% 4% 7% 40% Sign Control Stop Stop Stop Stop Traffic Vol by Lane 42 279 121 5 LT Vol 19 3 4 3 Through Vol 2 265 109 0 RT Vol 21 11 8 2 Lane Flow Rate 44 291 126 5 Geometry Grp 1 1 1 1 Degree of Util (X)0.056 0.328 0.166 0.007 Departure Headway (Hd)4.627 4.06 4.735 4.768 Convergence, Y/N Yes Yes Yes Yes Cap 779 872 746 755 Service Time 2.627 2.144 2.835 2.771 HCM Lane V/C Ratio 0.056 0.334 0.169 0.007 HCM Control Delay 7.9 9.2 8.8 7.8 HCM Lane LOS A A A A HCM 95th-tile Q 0.2 1.4 0.6 0 524 of 628 Lanes, Volumes, Timings 2: 46th Place S/44th Avenue S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - AM Peak Hour Page 3 Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)99 707 49 8 406 2 46 2 7 2 9 68 Future Volume (vph)99 707 49 8 406 2 46 2 7 2 9 68 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Storage Length (ft)0 0 0 0 0 0 0 50 Storage Lanes 0 0 0 0 0 0 0 1 Taper Length (ft)25 25 25 25 Link Speed (mph)35 35 35 25 Link Distance (ft)523 579 1356 280 Travel Time (s)10.2 11.3 26.4 7.6 Confl. Peds. (#/hr)2 2 2 2 Peak Hour Factor 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 Heavy Vehicles (%) 4% 3% 2% 14% 1% 0% 0% 0% 17% 0% 0% 0% Shared Lane Traffic (%) Sign Control Free Free Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 525 of 628 HCM 6th TWSC 2: 46th Place S/44th Avenue S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - AM Peak Hour Page 4 Intersection Int Delay, s/veh 9.8 Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 99 707 49 8 406 2 46 2 7 2 9 68 Future Vol, veh/h 99 707 49 8 406 2 46 2 7 2 9 68 Conflicting Peds, #/hr 2 0 0 0 0 2 0 0 0 2 0 2 Sign Control Free Free Free Free Free Free Stop Stop Stop Stop Stop Stop RT Channelized - - None - - None - - None - - Stop Storage Length - - - - - - - - - - - 50 Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 - Grade, % - 0 - - 0 - - 0 - - 0 - Peak Hour Factor 86 86 86 86 86 86 86 86 86 86 86 86 Heavy Vehicles, % 4 3 2 14 1 0 0 0 17 0 0 0 Mvmt Flow 115 822 57 9 472 2 53 2 8 2 10 79 Major/Minor Major1 Major2 Minor1 Minor2 Conflicting Flow All 476 0 0 879 0 0 1579 1575 853 1581 1602 477 Stage 1 - - - - - - 1081 1081 - 493 493 - Stage 2 - - - - - - 498 494 - 1088 1109 - Critical Hdwy 4.14 - - 4.24 - - 7.1 6.5 6.37 7.1 6.5 6.2 Critical Hdwy Stg 1 - - - - - - 6.1 5.5 - 6.1 5.5 - Critical Hdwy Stg 2 - - - - - - 6.1 5.5 - 6.1 5.5 - Follow-up Hdwy 2.236 - - 2.326 - - 3.5 4 3.453 3.5 4 3.3 Pot Cap-1 Maneuver 1076 - - 720 - - 89 111 337 89 107 592 Stage 1 - - - - - - 266 296 - 562 550 - Stage 2 - - - - - - 558 550 - 264 288 - Platoon blocked, %- -- - Mov Cap-1 Maneuver 1074 - - 720 - - 58 86 336 70 83 590 Mov Cap-2 Maneuver - - - - - - 58 86 - 70 83 - Stage 1 - - - - - - 210 233 - 442 540 - Stage 2 - - - - - - 465 540 - 201 227 - Approach EB WB NB SB HCM Control Delay, s 1 0.2 206.9 18.5 HCM LOS F C Minor Lane/Major Mvmt NBLn1 EBL EBT EBR WBL WBT WBR SBLn1 SBLn2 Capacity (veh/h)66 1074 - - 720 - - 80 590 HCM Lane V/C Ratio 0.969 0.107 - - 0.013 - - 0.16 0.134 HCM Control Delay (s) 206.9 8.8 0 - 10.1 0 - 58.4 12 HCM Lane LOS F A A - B A - F B HCM 95th %tile Q(veh)4.8 0.4 - - 0 - - 0.5 0.5 526 of 628 Lanes, Volumes, Timings 3: 46th Place S & S 324th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - AM Peak Hour Page 5 Lane Group WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Volume (vph)6 15 44 2 11 75 Future Volume (vph)6 15 44 2 11 75 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)25 35 35 Link Distance (ft)576 2425 1356 Travel Time (s)15.7 47.2 26.4 Peak Hour Factor 0.89 0.89 0.89 0.89 0.89 0.89 Heavy Vehicles (%) 0% 7% 5% 0% 0% 6% Shared Lane Traffic (%) Sign Control Stop Free Free Intersection Summary Area Type:Other Control Type: Unsignalized 527 of 628 HCM 6th TWSC 3: 46th Place S & S 324th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - AM Peak Hour Page 6 Intersection Int Delay, s/veh 1.7 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h 6 15 44 2 11 75 Future Vol, veh/h 6 15 44 2 11 75 Conflicting Peds, #/hr 0 0 0 0 0 0 Sign Control Stop Stop Free Free Free Free RT Channelized - None - None - None Storage Length 0 - - - - - Veh in Median Storage, # 0 - 0 - - 0 Grade, % 0 - 0 - - 0 Peak Hour Factor 89 89 89 89 89 89 Heavy Vehicles, % 0 7 5 0 0 6 Mvmt Flow 7 17 49 2 12 84 Major/Minor Minor1 Major1 Major2 Conflicting Flow All 158 50 0 0 51 0 Stage 1 50 - - - - - Stage 2 108 - - - - - Critical Hdwy 6.4 6.27 - - 4.1 - Critical Hdwy Stg 1 5.4 - - - - - Critical Hdwy Stg 2 5.4 - - - - - Follow-up Hdwy 3.5 3.363 - - 2.2 - Pot Cap-1 Maneuver 838 1004 - - 1568 - Stage 1 978 - - - - - Stage 2 921 - - - - - Platoon blocked, %- -- Mov Cap-1 Maneuver 831 1004 - - 1568 - Mov Cap-2 Maneuver 831 - - - - - Stage 1 978 - - - - - Stage 2 914 - - - - - Approach WB NB SB HCM Control Delay, s 8.9 0 0.9 HCM LOS A Minor Lane/Major Mvmt NBT NBR WBLn1 SBL SBT Capacity (veh/h)- - 948 1568 - HCM Lane V/C Ratio - - 0.025 0.008 - HCM Control Delay (s)- - 8.9 7.3 0 HCM Lane LOS - - A A A HCM 95th %tile Q(veh)- - 0.1 0 - 528 of 628 Lanes, Volumes, Timings 4: S 331st Street & 56th Avenue S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - AM Peak Hour Page 7 Lane Group EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Volume (vph)4 87 23 32 42 18 Future Volume (vph)4 87 23 32 42 18 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)35 35 35 Link Distance (ft)505 495 1127 Travel Time (s)9.8 9.6 22.0 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles (%) 25% 4% 0% 7% 3% 6% Shared Lane Traffic (%) Sign Control Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 529 of 628 HCM 6th AWSC 4: S 331st Street & 56th Avenue S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - AM Peak Hour Page 8 Intersection Intersection Delay, s/veh 7.7 Intersection LOS A Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h 4 87 23 32 42 18 Future Vol, veh/h 4 87 23 32 42 18 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles, % 25 4 0 7 3 6 Mvmt Flow 4 95 25 35 46 20 Number of Lanes 0 1 1 0 1 0 Approach EB WB SB Opposing Approach WB EB Opposing Lanes 1 1 0 Conflicting Approach Left SB WB Conflicting Lanes Left 1 0 1 Conflicting Approach Right SB EB Conflicting Lanes Right 0 1 1 HCM Control Delay 8.2 7.1 7.6 HCM LOS A A A Lane EBLn1 WBLn1 SBLn1 Vol Left, %4% 0% 70% Vol Thru, %96% 42% 0% Vol Right, %0% 58% 30% Sign Control Stop Stop Stop Traffic Vol by Lane 91 55 60 LT Vol 4 0 42 Through Vol 87 23 0 RT Vol 0 32 18 Lane Flow Rate 99 60 65 Geometry Grp 1 1 1 Degree of Util (X)0.123 0.062 0.076 Departure Headway (Hd)4.494 3.74 4.183 Convergence, Y/N Yes Yes Yes Cap 795 947 845 Service Time 2.538 1.806 2.267 HCM Lane V/C Ratio 0.125 0.063 0.077 HCM Control Delay 8.2 7.1 7.6 HCM Lane LOS A A A HCM 95th-tile Q 0.4 0.2 0.2 530 of 628 Lanes, Volumes, Timings 1: 56th Avenue S & S 316th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - PM Peak Hour Page 1 Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)1 245 19 26 276 7 28 4 15 20 9 10 Future Volume (vph)1 245 19 26 276 7 28 4 15 20 9 10 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Link Speed (mph)25 25 35 25 Link Distance (ft)668 578 3975 233 Travel Time (s)18.2 15.8 77.4 6.4 Confl. Peds. (#/hr)3 1 1 3 1 1 3 3 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles (%)0% 3% 0% 4% 2% 0% 4% 0% 0% 0% 0% 0% Shared Lane Traffic (%) Sign Control Stop Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 531 of 628 HCM 6th AWSC 1: 56th Avenue S & S 316th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - PM Peak Hour Page 2 Intersection Intersection Delay, s/veh 10.3 Intersection LOS B Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 1 245 19 26 276 7 28 4 15 20 9 10 Future Vol, veh/h 1 245 19 26 276 7 28 4 15 20 9 10 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles, % 0 3 0 4 2 0 4 0 0 0 0 0 Mvmt Flow 1 266 21 28 300 8 30 4 16 22 10 11 Number of Lanes 0 1 0 0 1 0 0 1 0 0 1 0 Approach EB WB NB SB Opposing Approach WB EB SB NB Opposing Lanes 1 1 1 1 Conflicting Approach Left SB NB EB WB Conflicting Lanes Left 1 1 1 1 Conflicting Approach Right NB SB WB EB Conflicting Lanes Right 1 1 1 1 HCM Control Delay 10 10.9 8.8 8.7 HCM LOS A B A A Lane NBLn1 EBLn1 WBLn1 SBLn1 Vol Left, %60% 0% 8% 51% Vol Thru, %9% 92% 89% 23% Vol Right, % 32% 7% 2% 26% Sign Control Stop Stop Stop Stop Traffic Vol by Lane 47 265 309 39 LT Vol 28 1 26 20 Through Vol 4 245 276 9 RT Vol 15 19 7 10 Lane Flow Rate 51 288 336 42 Geometry Grp 1 1 1 1 Degree of Util (X)0.076 0.358 0.422 0.063 Departure Headway (Hd)5.341 4.47 4.527 5.31 Convergence, Y/N Yes Yes Yes Yes Cap 667 804 793 671 Service Time 3.403 2.505 2.562 3.373 HCM Lane V/C Ratio 0.076 0.358 0.424 0.063 HCM Control Delay 8.8 10 10.9 8.7 HCM Lane LOS A A B A HCM 95th-tile Q 0.2 1.6 2.1 0.2 532 of 628 Lanes, Volumes, Timings 2: 46th Place S/44th Avenue S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - PM Peak Hour Page 3 Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)76 528 104 7 623 10 79 10 11 1 4 88 Future Volume (vph)76 528 104 7 623 10 79 10 11 1 4 88 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Storage Length (ft)0 0 0 0 0 0 0 50 Storage Lanes 0 0 0 0 0 0 0 1 Taper Length (ft)25 25 25 25 Link Speed (mph)35 35 35 25 Link Distance (ft)523 579 1356 280 Travel Time (s)10.2 11.3 26.4 7.6 Confl. Peds. (#/hr)1 1 1 1 Peak Hour Factor 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 Heavy Vehicles (%) 6% 1% 1% 0% 2% 0% 3% 0% 0% 0% 0% 3% Shared Lane Traffic (%) Sign Control Free Free Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 533 of 628 HCM 6th TWSC 2: 46th Place S/44th Avenue S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - PM Peak Hour Page 4 Intersection Int Delay, s/veh 22.7 Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 76 528 104 7 623 10 79 10 11 1 4 88 Future Vol, veh/h 76 528 104 7 623 10 79 10 11 1 4 88 Conflicting Peds, #/hr 1 0 1 0 0 0 1 0 0 0 0 1 Sign Control Free Free Free Free Free Free Stop Stop Stop Stop Stop Stop RT Channelized - - None - - None - - None - - Stop Storage Length - - - - - - - - - - - 50 Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 - Grade, % - 0 - - 0 - - 0 - - 0 - Peak Hour Factor 93 93 93 93 93 93 93 93 93 93 93 93 Heavy Vehicles, % 6 1 1 0 2 0 3 0 0 0 0 3 Mvmt Flow 82 568 112 8 670 11 85 11 12 1 4 95 Major/Minor Major1 Major2 Minor1 Minor2 Conflicting Flow All 682 0 0 681 0 0 1484 1487 625 1493 1538 678 Stage 1 - - - - - - 789 789 - 693 693 - Stage 2 - - - - - - 695 698 - 800 845 - Critical Hdwy 4.16 - - 4.1 - - 7.13 6.5 6.2 7.1 6.5 6.23 Critical Hdwy Stg 1 - - - - - - 6.13 5.5 - 6.1 5.5 - Critical Hdwy Stg 2 - - - - - - 6.13 5.5 - 6.1 5.5 - Follow-up Hdwy 2.254 - - 2.2 - - 3.527 4 3.3 3.5 4 3.327 Pot Cap-1 Maneuver 892 - - 921 - - 102 126 488 103 117 450 Stage 1 - - - - - - 382 405 - 437 448 - Stage 2 - - - - - - 431 445 - 382 382 - Platoon blocked, %- -- - Mov Cap-1 Maneuver 891 - - 920 - - ~ 68 105 488 81 98 449 Mov Cap-2 Maneuver - - - - - - ~ 68 105 - 81 98 - Stage 1 - - - - - - 324 343 - 371 441 - Stage 2 - - - - - - 332 438 - 307 324 - Approach EB WB NB SB HCM Control Delay, s 1 0.1 $ 325.8 16.7 HCM LOS F C Minor Lane/Major Mvmt NBLn1 EBL EBT EBR WBL WBT WBR SBLn1 SBLn2 Capacity (veh/h)78 891 - - 920 - - 94 449 HCM Lane V/C Ratio 1.379 0.092 - - 0.008 - - 0.057 0.211 HCM Control Delay (s) $ 325.8 9.4 0 - 8.9 0 - 45.6 15.1 HCM Lane LOS F A A - A A - E C HCM 95th %tile Q(veh)8.5 0.3 - - 0 - - 0.2 0.8 Notes ~: Volume exceeds capacity $: Delay exceeds 300s +: Computation Not Defined *: All major volume in platoon 534 of 628 Lanes, Volumes, Timings 3: 46th Place S & S 324th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - PM Peak Hour Page 5 Lane Group WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Volume (vph)4 12 86 1 17 89 Future Volume (vph)4 12 86 1 17 89 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)25 35 35 Link Distance (ft)576 2425 1356 Travel Time (s)15.7 47.2 26.4 Confl. Peds. (#/hr)3 3 3 3 Peak Hour Factor 0.88 0.88 0.88 0.88 0.88 0.88 Heavy Vehicles (%)25% 9% 3% 0% 7% 4% Shared Lane Traffic (%) Sign Control Stop Free Free Intersection Summary Area Type:Other Control Type: Unsignalized 535 of 628 HCM 6th TWSC 3: 46th Place S & S 324th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - PM Peak Hour Page 6 Intersection Int Delay, s/veh 1.3 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h 4 12 86 1 17 89 Future Vol, veh/h 4 12 86 1 17 89 Conflicting Peds, #/hr 3 3 0 3 3 0 Sign Control Stop Stop Free Free Free Free RT Channelized - None - None - None Storage Length 0 - - - - - Veh in Median Storage, # 0 - 0 - - 0 Grade, % 0 - 0 - - 0 Peak Hour Factor 88 88 88 88 88 88 Heavy Vehicles, % 25 9 3 0 7 4 Mvmt Flow 5 14 98 1 19 101 Major/Minor Minor1 Major1 Major2 Conflicting Flow All 244 105 0 0 102 0 Stage 1 102 - - - - - Stage 2 142 - - - - - Critical Hdwy 6.65 6.29 - - 4.17 - Critical Hdwy Stg 1 5.65 - - - - - Critical Hdwy Stg 2 5.65 - - - - - Follow-up Hdwy 3.725 3.381 - - 2.263 - Pot Cap-1 Maneuver 697 931 - - 1459 - Stage 1 868 - - - - - Stage 2 832 - - - - - Platoon blocked, %- -- Mov Cap-1 Maneuver 683 926 - - 1455 - Mov Cap-2 Maneuver 683 - - - - - Stage 1 865 - - - - - Stage 2 818 - - - - - Approach WB NB SB HCM Control Delay, s 9.3 0 1.2 HCM LOS A Minor Lane/Major Mvmt NBT NBR WBLn1 SBL SBT Capacity (veh/h)- - 850 1455 - HCM Lane V/C Ratio - - 0.021 0.013 - HCM Control Delay (s)- - 9.3 7.5 0 HCM Lane LOS - - A A A HCM 95th %tile Q(veh)- - 0.1 0 - 536 of 628 Lanes, Volumes, Timings 4: S 331st Street & 56th Avenue S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - PM Peak Hour Page 7 Lane Group EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Volume (vph)8 85 92 45 28 8 Future Volume (vph)8 85 92 45 28 8 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)35 35 35 Link Distance (ft)505 495 1127 Travel Time (s)9.8 9.6 22.0 Peak Hour Factor 0.82 0.82 0.82 0.82 0.82 0.82 Heavy Vehicles (%) 0% 5% 2% 0% 0% 0% Shared Lane Traffic (%) Sign Control Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 537 of 628 HCM 6th AWSC 4: S 331st Street & 56th Avenue S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 Baseline - PM Peak Hour Page 8 Intersection Intersection Delay, s/veh 7.8 Intersection LOS A Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h 8 85 92 45 28 8 Future Vol, veh/h 8 85 92 45 28 8 Peak Hour Factor 0.82 0.82 0.82 0.82 0.82 0.82 Heavy Vehicles, % 0 5 2 0 0 0 Mvmt Flow 10 104 112 55 34 10 Number of Lanes 0 1 1 0 1 0 Approach EB WB SB Opposing Approach WB EB Opposing Lanes 1 1 0 Conflicting Approach Left SB WB Conflicting Lanes Left 1 0 1 Conflicting Approach Right SB EB Conflicting Lanes Right 0 1 1 HCM Control Delay 7.8 7.8 7.8 HCM LOS A A A Lane EBLn1 WBLn1 SBLn1 Vol Left, %9% 0% 78% Vol Thru, %91% 67% 0% Vol Right, %0% 33% 22% Sign Control Stop Stop Stop Traffic Vol by Lane 93 137 36 LT Vol 8 0 28 Through Vol 85 92 0 RT Vol 0 45 8 Lane Flow Rate 113 167 44 Geometry Grp 1 1 1 Degree of Util (X)0.13 0.181 0.055 Departure Headway (Hd)4.121 3.899 4.514 Convergence, Y/N Yes Yes Yes Cap 863 912 798 Service Time 2.181 1.956 2.514 HCM Lane V/C Ratio 0.131 0.183 0.055 HCM Control Delay 7.8 7.8 7.8 HCM Lane LOS A A A HCM 95th-tile Q 0.4 0.7 0.2 538 of 628 Updated Transportation Impact Analysis Carbon Trails Residential 2023 With Project 539 of 628 Lanes, Volumes, Timings 1: 56th Avenue S & S 316th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 1 Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)3 265 11 6 109 8 20 2 25 3 0 2 Future Volume (vph)3 265 11 6 109 8 20 2 25 3 0 2 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Link Speed (mph)25 25 35 25 Link Distance (ft)668 578 3975 233 Travel Time (s)18.2 15.8 77.4 6.4 Confl. Peds. (#/hr)2 2 1 1 2 1 1 2 Peak Hour Factor 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 Heavy Vehicles (%)0% 2% 0% 33% 2% 14% 0% 0% 11% 0% 0% 0% Shared Lane Traffic (%) Sign Control Stop Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 540 of 628 HCM 6th AWSC 1: 56th Avenue S & S 316th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 2 Intersection Intersection Delay, s/veh 9 Intersection LOS A Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 3 265 11 6 109 8 20 2 25 3 0 2 Future Vol, veh/h 3 265 11 6 109 8 20 2 25 3 0 2 Peak Hour Factor 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 Heavy Vehicles, % 0 2 0 33 2 14 0 0 11 0 0 0 Mvmt Flow 3 276 11 6 114 8 21 2 26 3 0 2 Number of Lanes 0 1 0 0 1 0 0 1 0 0 1 0 Approach EB WB NB SB Opposing Approach WB EB SB NB Opposing Lanes 1 1 1 1 Conflicting Approach Left SB NB EB WB Conflicting Lanes Left 1 1 1 1 Conflicting Approach Right NB SB WB EB Conflicting Lanes Right 1 1 1 1 HCM Control Delay 9.2 8.9 7.9 7.8 HCM LOS A A A A Lane NBLn1 EBLn1 WBLn1 SBLn1 Vol Left, %43% 1% 5% 60% Vol Thru, %4% 95% 89% 0% Vol Right, % 53% 4% 7% 40% Sign Control Stop Stop Stop Stop Traffic Vol by Lane 47 279 123 5 LT Vol 20 3 6 3 Through Vol 2 265 109 0 RT Vol 25 11 8 2 Lane Flow Rate 49 291 128 5 Geometry Grp 1 1 1 1 Degree of Util (X)0.063 0.329 0.173 0.007 Departure Headway (Hd)4.609 4.072 4.855 4.783 Convergence, Y/N Yes Yes Yes Yes Cap 780 869 743 751 Service Time 2.616 2.165 2.855 2.793 HCM Lane V/C Ratio 0.063 0.335 0.172 0.007 HCM Control Delay 7.9 9.2 8.9 7.8 HCM Lane LOS A A A A HCM 95th-tile Q 0.2 1.4 0.6 0 541 of 628 Lanes, Volumes, Timings 2: 46th Place S/44th Avenue S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 3 Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)99 707 54 8 406 2 60 2 7 2 9 68 Future Volume (vph)99 707 54 8 406 2 60 2 7 2 9 68 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Storage Length (ft)0 0 0 0 0 0 0 50 Storage Lanes 0 0 0 0 0 0 0 1 Taper Length (ft)25 25 25 25 Link Speed (mph)35 35 35 25 Link Distance (ft)523 579 1356 280 Travel Time (s)10.2 11.3 26.4 7.6 Confl. Peds. (#/hr)2 2 2 2 Peak Hour Factor 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 Heavy Vehicles (%) 4% 3% 2% 14% 1% 0% 0% 0% 17% 0% 0% 0% Shared Lane Traffic (%) Sign Control Free Free Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 542 of 628 HCM 6th TWSC 2: 46th Place S/44th Avenue S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 4 Intersection Int Delay, s/veh 16.9 Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 99 707 54 8 406 2 60 2 7 2 9 68 Future Vol, veh/h 99 707 54 8 406 2 60 2 7 2 9 68 Conflicting Peds, #/hr 2 0 0 0 0 2 0 0 0 2 0 2 Sign Control Free Free Free Free Free Free Stop Stop Stop Stop Stop Stop RT Channelized - - None - - None - - None - - Stop Storage Length - - - - - - - - - - - 50 Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 - Grade, % - 0 - - 0 - - 0 - - 0 - Peak Hour Factor 86 86 86 86 86 86 86 86 86 86 86 86 Heavy Vehicles, % 4 3 2 14 1 0 0 0 17 0 0 0 Mvmt Flow 115 822 63 9 472 2 70 2 8 2 10 79 Major/Minor Major1 Major2 Minor1 Minor2 Conflicting Flow All 476 0 0 885 0 0 1582 1578 856 1584 1608 477 Stage 1 - - - - - - 1084 1084 - 493 493 - Stage 2 - - - - - - 498 494 - 1091 1115 - Critical Hdwy 4.14 - - 4.24 - - 7.1 6.5 6.37 7.1 6.5 6.2 Critical Hdwy Stg 1 - - - - - - 6.1 5.5 - 6.1 5.5 - Critical Hdwy Stg 2 - - - - - - 6.1 5.5 - 6.1 5.5 - Follow-up Hdwy 2.236 - - 2.326 - - 3.5 4 3.453 3.5 4 3.3 Pot Cap-1 Maneuver 1076 - - 717 - - 89 110 336 89 106 592 Stage 1 - - - - - - 265 296 - 562 550 - Stage 2 - - - - - - 558 550 - 263 286 - Platoon blocked, %- -- - Mov Cap-1 Maneuver 1074 - - 717 - - ~ 57 85 335 70 82 590 Mov Cap-2 Maneuver - - - - - - ~ 57 85 - 70 82 - Stage 1 - - - - - - 208 233 - 441 540 - Stage 2 - - - - - - 465 540 - 199 225 - Approach EB WB NB SB HCM Control Delay, s 1 0.2 $ 314.8 18.5 HCM LOS F C Minor Lane/Major Mvmt NBLn1 EBL EBT EBR WBL WBT WBR SBLn1 SBLn2 Capacity (veh/h)63 1074 - - 717 - - 80 590 HCM Lane V/C Ratio 1.274 0.107 - - 0.013 - - 0.16 0.134 HCM Control Delay (s) $ 314.8 8.8 0 - 10.1 0 - 58.4 12 HCM Lane LOS F A A - B A - F B HCM 95th %tile Q(veh)6.7 0.4 - - 0 - - 0.5 0.5 Notes ~: Volume exceeds capacity $: Delay exceeds 300s +: Computation Not Defined *: All major volume in platoon 543 of 628 Lanes, Volumes, Timings 3: 46th Place S & S 324th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 5 Lane Group WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Volume (vph)6 37 36 2 18 73 Future Volume (vph)6 37 36 2 18 73 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)25 35 35 Link Distance (ft)576 2425 1356 Travel Time (s)15.7 47.2 26.4 Peak Hour Factor 0.89 0.89 0.89 0.89 0.89 0.89 Heavy Vehicles (%) 0% 7% 5% 0% 0% 6% Shared Lane Traffic (%) Sign Control Stop Free Free Intersection Summary Area Type:Other Control Type: Unsignalized 544 of 628 HCM 6th TWSC 3: 46th Place S & S 324th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 6 Intersection Int Delay, s/veh 3 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h 6 37 36 2 18 73 Future Vol, veh/h 6 37 36 2 18 73 Conflicting Peds, #/hr 0 0 0 0 0 0 Sign Control Stop Stop Free Free Free Free RT Channelized - None - None - None Storage Length 0 - - - - - Veh in Median Storage, # 0 - 0 - - 0 Grade, % 0 - 0 - - 0 Peak Hour Factor 89 89 89 89 89 89 Heavy Vehicles, % 0 7 5 0 0 6 Mvmt Flow 7 42 40 2 20 82 Major/Minor Minor1 Major1 Major2 Conflicting Flow All 163 41 0 0 42 0 Stage 1 41 - - - - - Stage 2 122 - - - - - Critical Hdwy 6.4 6.27 - - 4.1 - Critical Hdwy Stg 1 5.4 - - - - - Critical Hdwy Stg 2 5.4 - - - - - Follow-up Hdwy 3.5 3.363 - - 2.2 - Pot Cap-1 Maneuver 832 1016 - - 1580 - Stage 1 987 - - - - - Stage 2 908 - - - - - Platoon blocked, %- -- Mov Cap-1 Maneuver 821 1016 - - 1580 - Mov Cap-2 Maneuver 821 - - - - - Stage 1 987 - - - - - Stage 2 896 - - - - - Approach WB NB SB HCM Control Delay, s 8.9 0 1.4 HCM LOS A Minor Lane/Major Mvmt NBT NBR WBLn1 SBL SBT Capacity (veh/h)- - 983 1580 - HCM Lane V/C Ratio - - 0.049 0.013 - HCM Control Delay (s)- - 8.9 7.3 0 HCM Lane LOS - - A A A HCM 95th %tile Q(veh)- - 0.2 0 - 545 of 628 Lanes, Volumes, Timings 4: S 331st Street & 56th Avenue S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 7 Lane Group EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Volume (vph)2 84 21 36 52 10 Future Volume (vph)2 84 21 36 52 10 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)35 35 35 Link Distance (ft)505 495 1127 Travel Time (s)9.8 9.6 22.0 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles (%) 25% 4% 0% 7% 3% 6% Shared Lane Traffic (%) Sign Control Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 546 of 628 HCM 6th AWSC 4: S 331st Street & 56th Avenue S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 8 Intersection Intersection Delay, s/veh 7.7 Intersection LOS A Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h 2 84 21 36 52 10 Future Vol, veh/h 2 84 21 36 52 10 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles, % 25 4 0 7 3 6 Mvmt Flow 2 91 23 39 57 11 Number of Lanes 0 1 1 0 1 0 Approach EB WB SB Opposing Approach WB EB Opposing Lanes 1 1 0 Conflicting Approach Left SB WB Conflicting Lanes Left 1 0 1 Conflicting Approach Right SB EB Conflicting Lanes Right 0 1 1 HCM Control Delay 8.1 7 7.8 HCM LOS A A A Lane EBLn1 WBLn1 SBLn1 Vol Left, %2% 0% 84% Vol Thru, %98% 37% 0% Vol Right, %0% 63% 16% Sign Control Stop Stop Stop Traffic Vol by Lane 86 57 62 LT Vol 2 0 52 Through Vol 84 21 0 RT Vol 0 36 10 Lane Flow Rate 93 62 67 Geometry Grp 1 1 1 Degree of Util (X)0.117 0.064 0.08 Departure Headway (Hd)4.496 3.71 4.289 Convergence, Y/N Yes Yes Yes Cap 794 954 825 Service Time 2.544 1.779 2.371 HCM Lane V/C Ratio 0.117 0.065 0.081 HCM Control Delay 8.1 7 7.8 HCM Lane LOS A A A HCM 95th-tile Q 0.4 0.2 0.3 547 of 628 Lanes, Volumes, Timings 5: 51st Avenue S & S 328th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 9 Lane Group WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Volume (vph)1 24 4 0 10 5 Future Volume (vph)1 24 4 0 10 5 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)25 25 25 Link Distance (ft)1340 991 404 Travel Time (s)36.5 27.0 11.0 Peak Hour Factor 0.36 0.36 0.36 0.36 0.36 0.36 Heavy Vehicles (%) 3% 3% 0% 3% 3% 0% Shared Lane Traffic (%) Sign Control Stop Free Free Intersection Summary Area Type:Other Control Type: Unsignalized 548 of 628 HCM 6th TWSC 5: 51st Avenue S & S 328th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 10 Intersection Int Delay, s/veh 6.6 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h 1 24 4 0 10 5 Future Vol, veh/h 1 24 4 0 10 5 Conflicting Peds, #/hr 0 0 0 0 0 0 Sign Control Stop Stop Free Free Free Free RT Channelized - None - None - None Storage Length 0 - - - - - Veh in Median Storage, # 0 - 0 - - 0 Grade, % 0 - 0 - - 0 Peak Hour Factor 36 36 36 36 36 36 Heavy Vehicles, % 3 3 0 3 3 0 Mvmt Flow 3 67 11 0 28 14 Major/Minor Minor1 Major1 Major2 Conflicting Flow All 81 11 0 0 11 0 Stage 1 11 - - - - - Stage 2 70 - - - - - Critical Hdwy 6.43 6.23 - - 4.13 - Critical Hdwy Stg 1 5.43 - - - - - Critical Hdwy Stg 2 5.43 - - - - - Follow-up Hdwy 3.527 3.327 - - 2.227 - Pot Cap-1 Maneuver 919 1067 - - 1602 - Stage 1 1009 - - - - - Stage 2 950 - - - - - Platoon blocked, %- -- Mov Cap-1 Maneuver 902 1067 - - 1602 - Mov Cap-2 Maneuver 902 - - - - - Stage 1 1009 - - - - - Stage 2 933 - - - - - Approach WB NB SB HCM Control Delay, s 8.6 0 4.9 HCM LOS A Minor Lane/Major Mvmt NBT NBR WBLn1 SBL SBT Capacity (veh/h)- - 1059 1602 - HCM Lane V/C Ratio - - 0.066 0.017 - HCM Control Delay (s)- - 8.6 7.3 0 HCM Lane LOS - - A A A HCM 95th %tile Q(veh)- - 0.2 0.1 - 549 of 628 Lanes, Volumes, Timings 6: 56th Avenue S & S 328th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 11 Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)8 0 9 17 3 7 4 32 6 0 24 7 Future Volume (vph)8 0 9 17 3 7 4 32 6 0 24 7 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Link Speed (mph)25 25 35 35 Link Distance (ft)1340 455 1127 3975 Travel Time (s)36.5 12.4 22.0 77.4 Peak Hour Factor 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77 Heavy Vehicles (%) 3% 3% 3% 0% 3% 17% 3% 7% 20% 0% 8% 3% Shared Lane Traffic (%) Sign Control Stop Stop Free Free Intersection Summary Area Type:Other Control Type: Unsignalized 550 of 628 HCM 6th TWSC 6: 56th Avenue S & S 328th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour Page 12 Intersection Int Delay, s/veh 3.7 Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 8 0 9 17 3 7 4 32 6 0 24 7 Future Vol, veh/h 8 0 9 17 3 7 4 32 6 0 24 7 Conflicting Peds, #/hr 0 0 0 0 0 0 0 0 0 0 0 0 Sign Control Stop Stop Stop Stop Stop Stop Free Free Free Free Free Free RT Channelized - - None - - None - - None - - None Storage Length - - - - - - - - - - - - Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 - Grade, % - 0 - - 0 - - 0 - - 0 - Peak Hour Factor 77 77 77 77 77 77 77 77 77 77 77 77 Heavy Vehicles, % 3 3 3 0 3 17 3 7 20 0 8 3 Mvmt Flow 10 0 12 22 4 9 5 42 8 0 31 9 Major/Minor Minor2 Minor1 Major1 Major2 Conflicting Flow All 99 96 36 98 96 46 40 0 0 50 0 0 Stage 1 36 36 - 56 56 - - - - - - - Stage 2 63 60 - 42 40 - - - - - - - Critical Hdwy 7.13 6.53 6.23 7.1 6.53 6.37 4.13 - - 4.1 - - Critical Hdwy Stg 1 6.13 5.53 - 6.1 5.53 - - - - - - - Critical Hdwy Stg 2 6.13 5.53 - 6.1 5.53 - - - - - - - Follow-up Hdwy 3.527 4.027 3.327 3.5 4.027 3.453 2.227 - - 2.2 - - Pot Cap-1 Maneuver 880 792 1034 889 792 982 1563 - - 1570 - - Stage 1 977 863 - 961 846 - - - - - - - Stage 2 945 843 - 978 860 - - - - - - - Platoon blocked, %- -- - Mov Cap-1 Maneuver 867 790 1034 877 790 982 1563 - - 1570 - - Mov Cap-2 Maneuver 867 790 - 877 790 - - - - - - - Stage 1 974 863 - 958 843 - - - - - - - Stage 2 929 840 - 967 860 - - - - - - - Approach EB WB NB SB HCM Control Delay, s 8.9 9.2 0.7 0 HCM LOS A A Minor Lane/Major Mvmt NBL NBT NBR EBLn1 WBLn1 SBL SBT SBR Capacity (veh/h)1563 - - 948 891 1570 - - HCM Lane V/C Ratio 0.003 - - 0.023 0.039 - - - HCM Control Delay (s)7.3 0 - 8.9 9.2 0 - - HCM Lane LOS A A - A A A - - HCM 95th %tile Q(veh)0 - - 0.1 0.1 0 - - 551 of 628 Lanes, Volumes, Timings 1: 56th Avenue S & S 316th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 1 Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)1 245 21 31 276 7 29 4 18 20 9 10 Future Volume (vph)1 245 21 31 276 7 29 4 18 20 9 10 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Link Speed (mph)25 25 35 25 Link Distance (ft)668 578 3975 233 Travel Time (s)18.2 15.8 77.4 6.4 Confl. Peds. (#/hr)3 1 1 3 1 1 3 3 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles (%)0% 3% 0% 4% 2% 0% 4% 0% 0% 0% 0% 0% Shared Lane Traffic (%) Sign Control Stop Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 552 of 628 HCM 6th AWSC 1: 56th Avenue S & S 316th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 2 Intersection Intersection Delay, s/veh 10.4 Intersection LOS B Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 1 245 21 31 276 7 29 4 18 20 9 10 Future Vol, veh/h 1 245 21 31 276 7 29 4 18 20 9 10 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 Heavy Vehicles, % 0 3 0 4 2 0 4 0 0 0 0 0 Mvmt Flow 1 266 23 34 300 8 32 4 20 22 10 11 Number of Lanes 0 1 0 0 1 0 0 1 0 0 1 0 Approach EB WB NB SB Opposing Approach WB EB SB NB Opposing Lanes 1 1 1 1 Conflicting Approach Left SB NB EB WB Conflicting Lanes Left 1 1 1 1 Conflicting Approach Right NB SB WB EB Conflicting Lanes Right 1 1 1 1 HCM Control Delay 10.1 11 8.9 8.8 HCM LOS B B A A Lane NBLn1 EBLn1 WBLn1 SBLn1 Vol Left, %57% 0% 10% 51% Vol Thru, %8% 92% 88% 23% Vol Right, % 35% 8% 2% 26% Sign Control Stop Stop Stop Stop Traffic Vol by Lane 51 267 314 39 LT Vol 29 1 31 20 Through Vol 4 245 276 9 RT Vol 18 21 7 10 Lane Flow Rate 55 290 341 42 Geometry Grp 1 1 1 1 Degree of Util (X)0.082 0.361 0.431 0.063 Departure Headway (Hd)5.336 4.483 4.544 5.338 Convergence, Y/N Yes Yes Yes Yes Cap 668 801 792 667 Service Time 3.398 2.522 2.581 3.402 HCM Lane V/C Ratio 0.082 0.362 0.431 0.063 HCM Control Delay 8.9 10.1 11 8.8 HCM Lane LOS A B B A HCM 95th-tile Q 0.3 1.7 2.2 0.2 553 of 628 Lanes, Volumes, Timings 2: 46th Place S/44th Avenue S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 3 Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)76 528 118 7 623 10 88 10 11 1 4 88 Future Volume (vph)76 528 118 7 623 10 88 10 11 1 4 88 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Storage Length (ft)0 0 0 0 0 0 0 50 Storage Lanes 0 0 0 0 0 0 0 1 Taper Length (ft)25 25 25 25 Link Speed (mph)35 35 35 25 Link Distance (ft)523 579 1356 280 Travel Time (s)10.2 11.3 26.4 7.6 Confl. Peds. (#/hr)1 1 1 1 Peak Hour Factor 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 Heavy Vehicles (%) 6% 1% 1% 0% 2% 0% 3% 0% 0% 0% 0% 3% Shared Lane Traffic (%) Sign Control Free Free Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 554 of 628 HCM 6th TWSC 2: 46th Place S/44th Avenue S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 4 Intersection Int Delay, s/veh 28.9 Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 76 528 118 7 623 10 88 10 11 1 4 88 Future Vol, veh/h 76 528 118 7 623 10 88 10 11 1 4 88 Conflicting Peds, #/hr 1 0 1 0 0 0 1 0 0 0 0 1 Sign Control Free Free Free Free Free Free Stop Stop Stop Stop Stop Stop RT Channelized - - None - - None - - None - - Stop Storage Length - - - - - - - - - - - 50 Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 - Grade, % - 0 - - 0 - - 0 - - 0 - Peak Hour Factor 93 93 93 93 93 93 93 93 93 93 93 93 Heavy Vehicles, % 6 1 1 0 2 0 3 0 0 0 0 3 Mvmt Flow 82 568 127 8 670 11 95 11 12 1 4 95 Major/Minor Major1 Major2 Minor1 Minor2 Conflicting Flow All 682 0 0 696 0 0 1492 1495 633 1500 1553 678 Stage 1 - - - - - - 797 797 - 693 693 - Stage 2 - - - - - - 695 698 - 807 860 - Critical Hdwy 4.16 - - 4.1 - - 7.13 6.5 6.2 7.1 6.5 6.23 Critical Hdwy Stg 1 - - - - - - 6.13 5.5 - 6.1 5.5 - Critical Hdwy Stg 2 - - - - - - 6.13 5.5 - 6.1 5.5 - Follow-up Hdwy 2.254 - - 2.2 - - 3.527 4 3.3 3.5 4 3.327 Pot Cap-1 Maneuver 892 - - 909 - - 101 124 483 101 114 450 Stage 1 - - - - - - 379 401 - 437 448 - Stage 2 - - - - - - 431 445 - 378 376 - Platoon blocked, %- -- - Mov Cap-1 Maneuver 891 - - 908 - - ~ 67 103 483 79 95 449 Mov Cap-2 Maneuver - - - - - - ~ 67 103 - 79 95 - Stage 1 - - - - - - 321 339 - 370 441 - Stage 2 - - - - - - 332 438 - 302 318 - Approach EB WB NB SB HCM Control Delay, s 1 0.1 $ 392.9 16.8 HCM LOS F C Minor Lane/Major Mvmt NBLn1 EBL EBT EBR WBL WBT WBR SBLn1 SBLn2 Capacity (veh/h)76 891 - - 908 - - 91 449 HCM Lane V/C Ratio 1.542 0.092 - - 0.008 - - 0.059 0.211 HCM Control Delay (s) $ 392.9 9.4 0 - 9 0 - 47 15.1 HCM Lane LOS F A A - A A - E C HCM 95th %tile Q(veh)9.7 0.3 - - 0 - - 0.2 0.8 Notes ~: Volume exceeds capacity $: Delay exceeds 300s +: Computation Not Defined *: All major volume in platoon 555 of 628 Lanes, Volumes, Timings 3: 46th Place S & S 324th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 5 Lane Group WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Volume (vph)4 25 82 1 35 85 Future Volume (vph)4 25 82 1 35 85 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)25 35 35 Link Distance (ft)576 2425 1356 Travel Time (s)15.7 47.2 26.4 Confl. Peds. (#/hr)3 3 3 3 Peak Hour Factor 0.88 0.88 0.88 0.88 0.88 0.88 Heavy Vehicles (%)25% 9% 3% 0% 7% 4% Shared Lane Traffic (%) Sign Control Stop Free Free Intersection Summary Area Type:Other Control Type: Unsignalized 556 of 628 HCM 6th TWSC 3: 46th Place S & S 324th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 6 Intersection Int Delay, s/veh 2.3 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h 4 25 82 1 35 85 Future Vol, veh/h 4 25 82 1 35 85 Conflicting Peds, #/hr 3 3 0 3 3 0 Sign Control Stop Stop Free Free Free Free RT Channelized - None - None - None Storage Length 0 - - - - - Veh in Median Storage, # 0 - 0 - - 0 Grade, % 0 - 0 - - 0 Peak Hour Factor 88 88 88 88 88 88 Heavy Vehicles, % 25 9 3 0 7 4 Mvmt Flow 5 28 93 1 40 97 Major/Minor Minor1 Major1 Major2 Conflicting Flow All 277 100 0 0 97 0 Stage 1 97 - - - - - Stage 2 180 - - - - - Critical Hdwy 6.65 6.29 - - 4.17 - Critical Hdwy Stg 1 5.65 - - - - - Critical Hdwy Stg 2 5.65 - - - - - Follow-up Hdwy 3.725 3.381 - - 2.263 - Pot Cap-1 Maneuver 666 937 - - 1466 - Stage 1 872 - - - - - Stage 2 799 - - - - - Platoon blocked, %- -- Mov Cap-1 Maneuver 643 932 - - 1462 - Mov Cap-2 Maneuver 643 - - - - - Stage 1 869 - - - - - Stage 2 773 - - - - - Approach WB NB SB HCM Control Delay, s 9.3 0 2.2 HCM LOS A Minor Lane/Major Mvmt NBT NBR WBLn1 SBL SBT Capacity (veh/h)- - 878 1462 - HCM Lane V/C Ratio - - 0.038 0.027 - HCM Control Delay (s)- - 9.3 7.5 0 HCM Lane LOS - - A A A HCM 95th %tile Q(veh)- - 0.1 0.1 - 557 of 628 Lanes, Volumes, Timings 4: S 331st Street & 56th Avenue S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 7 Lane Group EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Volume (vph)4 83 84 60 34 4 Future Volume (vph)4 83 84 60 34 4 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)35 35 35 Link Distance (ft)505 495 1127 Travel Time (s)9.8 9.6 22.0 Peak Hour Factor 0.82 0.82 0.82 0.82 0.82 0.82 Heavy Vehicles (%) 0% 5% 2% 0% 0% 0% Shared Lane Traffic (%) Sign Control Stop Stop Stop Intersection Summary Area Type:Other Control Type: Unsignalized 558 of 628 HCM 6th AWSC 4: S 331st Street & 56th Avenue S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 8 Intersection Intersection Delay, s/veh 7.8 Intersection LOS A Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h 4 83 84 60 34 4 Future Vol, veh/h 4 83 84 60 34 4 Peak Hour Factor 0.82 0.82 0.82 0.82 0.82 0.82 Heavy Vehicles, % 0 5 2 0 0 0 Mvmt Flow 5 101 102 73 41 5 Number of Lanes 0 1 1 0 1 0 Approach EB WB SB Opposing Approach WB EB Opposing Lanes 1 1 0 Conflicting Approach Left SB WB Conflicting Lanes Left 1 0 1 Conflicting Approach Right SB EB Conflicting Lanes Right 0 1 1 HCM Control Delay 7.8 7.8 7.9 HCM LOS A A A Lane EBLn1 WBLn1 SBLn1 Vol Left, %5% 0% 89% Vol Thru, %95% 58% 0% Vol Right, %0% 42% 11% Sign Control Stop Stop Stop Traffic Vol by Lane 87 144 38 LT Vol 4 0 34 Through Vol 83 84 0 RT Vol 0 60 4 Lane Flow Rate 106 176 46 Geometry Grp 1 1 1 Degree of Util (X)0.122 0.188 0.059 Departure Headway (Hd)4.123 3.844 4.606 Convergence, Y/N Yes Yes Yes Cap 862 925 782 Service Time 2.187 1.904 2.606 HCM Lane V/C Ratio 0.123 0.19 0.059 HCM Control Delay 7.8 7.8 7.9 HCM Lane LOS A A A HCM 95th-tile Q 0.4 0.7 0.2 559 of 628 Lanes, Volumes, Timings 5: 51st Avenue S & S 328th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 9 Lane Group WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Volume (vph)1 21 7 0 20 4 Future Volume (vph)1 21 7 0 20 4 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)25 25 25 Link Distance (ft)1340 991 404 Travel Time (s)36.5 27.0 11.0 Confl. Peds. (#/hr)6 4 6 4 Peak Hour Factor 0.83 0.83 0.83 0.83 0.83 0.83 Heavy Vehicles (%)3% 3% 14% 3% 3% 0% Shared Lane Traffic (%) Sign Control Stop Free Free Intersection Summary Area Type:Other Control Type: Unsignalized 560 of 628 HCM 6th TWSC 5: 51st Avenue S & S 328th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 10 Intersection Int Delay, s/veh 6.3 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h 1 21 7 0 20 4 Future Vol, veh/h 1 21 7 0 20 4 Conflicting Peds, #/hr 6 4 0 6 4 0 Sign Control Stop Stop Free Free Free Free RT Channelized - None - None - None Storage Length 0 - - - - - Veh in Median Storage, # 0 - 0 - - 0 Grade, % 0 - 0 - - 0 Peak Hour Factor 83 83 83 83 83 83 Heavy Vehicles, % 3 3 14 3 3 0 Mvmt Flow 1 25 8 0 24 5 Major/Minor Minor1 Major1 Major2 Conflicting Flow All 73 18 0 0 14 0 Stage 1 14 - - - - - Stage 2 59 - - - - - Critical Hdwy 6.43 6.23 - - 4.13 - Critical Hdwy Stg 1 5.43 - - - - - Critical Hdwy Stg 2 5.43 - - - - - Follow-up Hdwy 3.527 3.327 - - 2.227 - Pot Cap-1 Maneuver 928 1058 - - 1598 - Stage 1 1006 - - - - - Stage 2 961 - - - - - Platoon blocked, %- -- Mov Cap-1 Maneuver 903 1048 - - 1589 - Mov Cap-2 Maneuver 903 - - - - - Stage 1 1000 - - - - - Stage 2 941 - - - - - Approach WB NB SB HCM Control Delay, s 8.6 0 6.1 HCM LOS A Minor Lane/Major Mvmt NBT NBR WBLn1 SBL SBT Capacity (veh/h)- - 1040 1589 - HCM Lane V/C Ratio - - 0.025 0.015 - HCM Control Delay (s)- - 8.6 7.3 0 HCM Lane LOS - - A A A HCM 95th %tile Q(veh)- - 0.1 0 - 561 of 628 Lanes, Volumes, Timings 6: 56th Avenue S & S 328th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 11 Lane Group EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Volume (vph)7 1 6 2 0 4 14 47 10 8 30 12 Future Volume (vph)7 1 6 2 0 4 14 47 10 8 30 12 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Link Speed (mph)25 25 35 35 Link Distance (ft)1340 455 1127 3975 Travel Time (s)36.5 12.4 22.0 77.4 Confl. Peds. (#/hr)1 1 1 1 Peak Hour Factor 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 Heavy Vehicles (%)3% 3% 3% 0% 0% 0% 3% 0% 0% 0% 0% 3% Shared Lane Traffic (%) Sign Control Stop Stop Free Free Intersection Summary Area Type:Other Control Type: Unsignalized 562 of 628 HCM 6th TWSC 6: 56th Avenue S & S 328th Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour Page 12 Intersection Int Delay, s/veh 2.5 Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations Traffic Vol, veh/h 7 1 6 2 0 4 14 47 10 8 30 12 Future Vol, veh/h 7 1 6 2 0 4 14 47 10 8 30 12 Conflicting Peds, #/hr 0 0 0 1 0 1 0 0 1 1 0 0 Sign Control Stop Stop Stop Stop Stop Stop Free Free Free Free Free Free RT Channelized - - None - - None - - None - - None Storage Length - - - - - - - - - - - - Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 - Grade, % - 0 - - 0 - - 0 - - 0 - Peak Hour Factor 75 75 75 75 75 75 75 75 75 75 75 75 Heavy Vehicles, % 3 3 3 0 0 0 3 0 0 0 0 3 Mvmt Flow 9 1 8 3 0 5 19 63 13 11 40 16 Major/Minor Minor2 Minor1 Major1 Major2 Conflicting Flow All 181 185 49 185 187 72 56 0 0 77 0 0 Stage 1 70 70 - 109 109 - - - - - - - Stage 2 111 115 - 76 78 - - - - - - - Critical Hdwy 7.13 6.53 6.23 7.1 6.5 6.2 4.13 - - 4.1 - - Critical Hdwy Stg 1 6.13 5.53 - 6.1 5.5 - - - - - - - Critical Hdwy Stg 2 6.13 5.53 - 6.1 5.5 - - - - - - - Follow-up Hdwy 3.527 4.027 3.327 3.5 4 3.3 2.227 - - 2.2 - - Pot Cap-1 Maneuver 778 708 1017 780 711 996 1542 - - 1535 - - Stage 1 937 835 - 901 809 - - - - - - - Stage 2 892 798 - 938 834 - - - - - - - Platoon blocked, %- -- - Mov Cap-1 Maneuver 762 693 1016 760 696 994 1542 - - 1534 - - Mov Cap-2 Maneuver 762 693 - 760 696 - - - - - - - Stage 1 925 829 - 888 798 - - - - - - - Stage 2 875 787 - 922 828 - - - - - - - Approach EB WB NB SB HCM Control Delay, s 9.3 9 1.5 1.2 HCM LOS A A Minor Lane/Major Mvmt NBL NBT NBR EBLn1 WBLn1 SBL SBT SBR Capacity (veh/h)1542 - - 847 901 1534 - - HCM Lane V/C Ratio 0.012 - - 0.022 0.009 0.007 - - HCM Control Delay (s)7.4 0 - 9.3 9 7.4 0 - HCM Lane LOS A A - A A A A - HCM 95th %tile Q(veh)0 - - 0.1 0 0 - - 563 of 628 Updated Transportation Impact Analysis Carbon Trails Residential 2023 With Project With City Planned Improvement 564 of 628 Lanes, Volumes, Timings 8: S 321st Street & 44th Ave S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour (With City Planned Improvement)Page 1 Lane Group EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Volume (vph)99 761 466 4 11 68 Future Volume (vph)99 761 466 4 11 68 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Storage Length (ft)0 0 0 50 Storage Lanes 0 0 1 1 Taper Length (ft)25 25 Link Speed (mph)35 35 35 Link Distance (ft)327 196 363 Travel Time (s)6.4 3.8 7.1 Confl. Peds. (#/hr)2 2 Peak Hour Factor 0.86 0.86 0.86 0.86 0.86 0.86 Heavy Vehicles (%) 4% 3% 3% 0% 0% 0% Shared Lane Traffic (%) Sign Control Free Free Stop Intersection Summary Area Type:Other Control Type: Unsignalized 565 of 628 HCM 6th TWSC 8: S 321st Street & 44th Ave S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour (With City Planned Improvement)Page 2 Intersection Int Delay, s/veh 1.7 Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h 99 761 466 4 11 68 Future Vol, veh/h 99 761 466 4 11 68 Conflicting Peds, #/hr 2 0 0 2 0 0 Sign Control Free Free Free Free Stop Stop RT Channelized - None - None - Stop Storage Length - - - - 0 50 Veh in Median Storage, # - 0 0 - 0 - Grade, % - 0 0 - 0 - Peak Hour Factor 86 86 86 86 86 86 Heavy Vehicles, % 4 3 3 0 0 0 Mvmt Flow 115 885 542 5 13 79 Major/Minor Major1 Major2 Minor2 Conflicting Flow All 549 0 - 0 1662 547 Stage 1 - - - - 547 - Stage 2 - - - - 1115 - Critical Hdwy 4.14 - - - 6.4 6.2 Critical Hdwy Stg 1 - - - - 5.4 - Critical Hdwy Stg 2 - - - - 5.4 - Follow-up Hdwy 2.236 - - - 3.5 3.3 Pot Cap-1 Maneuver 1011 - - - 108 541 Stage 1 - - - - 584 - Stage 2 - - - - 316 - Platoon blocked, %- - - Mov Cap-1 Maneuver 1009 - - - 83 540 Mov Cap-2 Maneuver - - - - 83 - Stage 1 - - - - 452 - Stage 2 - - - - 315 - Approach EB WB SB HCM Control Delay, s 1 0 18.8 HCM LOS C Minor Lane/Major Mvmt EBL EBT WBT WBR SBLn1 SBLn2 Capacity (veh/h)1009 - - - 83 540 HCM Lane V/C Ratio 0.114 - - - 0.154 0.146 HCM Control Delay (s)9 0 - - 56.1 12.8 HCM Lane LOS A A - - F B HCM 95th %tile Q(veh)0.4 - - - 0.5 0.5 566 of 628 Lanes, Volumes, Timings 9: 46th Place S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour (With City Planned Improvement)Page 3 Lane Group EBT EBR WBL WBT NBL NBR Lane Configurations Traffic Volume (vph)709 63 8 408 62 7 Future Volume (vph)709 63 8 408 62 7 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)35 35 35 Link Distance (ft)196 579 1356 Travel Time (s)3.8 11.3 26.4 Peak Hour Factor 0.86 0.86 0.86 0.86 0.86 0.86 Heavy Vehicles (%) 3% 2% 14% 1% 0% 17% Shared Lane Traffic (%) Sign Control Free Free Stop Intersection Summary Area Type:Other Control Type: Unsignalized 567 of 628 HCM 6th TWSC 9: 46th Place S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - AM Peak Hour (With City Planned Improvement)Page 4 Intersection Int Delay, s/veh 2.4 Movement EBT EBR WBL WBT NBL NBR Lane Configurations Traffic Vol, veh/h 709 63 8 408 62 7 Future Vol, veh/h 709 63 8 408 62 7 Conflicting Peds, #/hr 0 0 0 0 0 0 Sign Control Free Free Free Free Stop Stop RT Channelized - None - None - None Storage Length - - - - 0 - Veh in Median Storage, # 0 - - 0 0 - Grade, % 0 - - 0 0 - Peak Hour Factor 86 86 86 86 86 86 Heavy Vehicles, % 3 2 14 1 0 17 Mvmt Flow 824 73 9 474 72 8 Major/Minor Major1 Major2 Minor1 Conflicting Flow All 0 0 897 0 1353 861 Stage 1 - - - - 861 - Stage 2 - - - - 492 - Critical Hdwy - - 4.24 - 6.4 6.37 Critical Hdwy Stg 1 - - - - 5.4 - Critical Hdwy Stg 2 - - - - 5.4 - Follow-up Hdwy - - 2.326 - 3.5 3.453 Pot Cap-1 Maneuver - - 709 - 167 334 Stage 1 - - - - 417 - Stage 2 - - - - 619 - Platoon blocked, % - -- Mov Cap-1 Maneuver - - 709 - 164 334 Mov Cap-2 Maneuver - - - - 164 - Stage 1 - - - - 417 - Stage 2 - - - - 608 - Approach EB WB NB HCM Control Delay, s 0 0.2 42.6 HCM LOS E Minor Lane/Major Mvmt NBLn1 EBT EBR WBL WBT Capacity (veh/h)173 - - 709 - HCM Lane V/C Ratio 0.464 - - 0.013 - HCM Control Delay (s) 42.6 - - 10.1 0 HCM Lane LOS E - - B A HCM 95th %tile Q(veh)2.2 - - 0 - 568 of 628 Lanes, Volumes, Timings 8: S 321st Street & 44th Ave S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour (With City Planned Improvement)Page 1 Lane Group EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Volume (vph)76 646 711 20 5 88 Future Volume (vph)76 646 711 20 5 88 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Storage Length (ft)0 0 0 50 Storage Lanes 0 0 1 1 Taper Length (ft)25 25 Link Speed (mph)35 35 35 Link Distance (ft)257 196 351 Travel Time (s)5.0 3.8 6.8 Confl. Peds. (#/hr)1 Peak Hour Factor 0.93 0.93 0.93 0.93 0.93 0.93 Heavy Vehicles (%) 6% 1% 2% 0% 0% 3% Shared Lane Traffic (%) Sign Control Free Free Stop Intersection Summary Area Type:Other Control Type: Unsignalized 569 of 628 HCM 6th TWSC 8: S 321st Street & 44th Ave S 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour (With City Planned Improvement)Page 2 Intersection Int Delay, s/veh 1.6 Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h 76 646 711 20 5 88 Future Vol, veh/h 76 646 711 20 5 88 Conflicting Peds, #/hr 0 0 0 0 0 1 Sign Control Free Free Free Free Stop Stop RT Channelized - None - None - Stop Storage Length - - - - 0 50 Veh in Median Storage, # - 0 0 - 0 - Grade, % - 0 0 - 0 - Peak Hour Factor 93 93 93 93 93 93 Heavy Vehicles, % 6 1 2 0 0 3 Mvmt Flow 82 695 765 22 5 95 Major/Minor Major1 Major2 Minor2 Conflicting Flow All 787 0 - 0 1635 777 Stage 1 - - - - 776 - Stage 2 - - - - 859 - Critical Hdwy 4.16 - - - 6.4 6.23 Critical Hdwy Stg 1 - - - - 5.4 - Critical Hdwy Stg 2 - - - - 5.4 - Follow-up Hdwy 2.254 - - - 3.5 3.327 Pot Cap-1 Maneuver 815 - - - 112 395 Stage 1 - - - - 457 - Stage 2 - - - - 418 - Platoon blocked, %- - - Mov Cap-1 Maneuver 815 - - - 94 395 Mov Cap-2 Maneuver - - - - 94 - Stage 1 - - - - 382 - Stage 2 - - - - 418 - Approach EB WB SB HCM Control Delay, s 1 0 18.5 HCM LOS C Minor Lane/Major Mvmt EBL EBT WBT WBR SBLn1 SBLn2 Capacity (veh/h)815 - - - 94 395 HCM Lane V/C Ratio 0.1 - - - 0.057 0.24 HCM Control Delay (s)9.9 0 - - 45.6 17 HCM Lane LOS A A - - E C HCM 95th %tile Q(veh)0.3 - - - 0.2 0.9 570 of 628 Lanes, Volumes, Timings 9: 46th Place S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour (With City Planned Improvement)Page 3 Lane Group EBT EBR WBL WBT NBL NBR Lane Configurations Traffic Volume (vph)529 122 7 633 98 11 Future Volume (vph)529 122 7 633 98 11 Ideal Flow (vphpl)1900 1900 1900 1900 1900 1900 Link Speed (mph)35 35 35 Link Distance (ft)196 579 1356 Travel Time (s)3.8 11.3 26.4 Peak Hour Factor 0.93 0.93 0.93 0.93 0.93 0.93 Heavy Vehicles (%) 1% 1% 0% 2% 3% 0% Shared Lane Traffic (%) Sign Control Free Free Stop Intersection Summary Area Type:Other Control Type: Unsignalized 571 of 628 HCM 6th TWSC 9: 46th Place S & S 321st Street 04/15/2021 Carbon Trails Residential Synchro 10 Report 2023 With Project - PM Peak Hour (With City Planned Improvement)Page 4 Intersection Int Delay, s/veh 4.5 Movement EBT EBR WBL WBT NBL NBR Lane Configurations Traffic Vol, veh/h 529 122 7 633 98 11 Future Vol, veh/h 529 122 7 633 98 11 Conflicting Peds, #/hr 0 0 0 0 0 0 Sign Control Free Free Free Free Stop Stop RT Channelized - None - None - None Storage Length - - - - 0 - Veh in Median Storage, # 0 - - 0 0 - Grade, % 0 - - 0 0 - Peak Hour Factor 93 93 93 93 93 93 Heavy Vehicles, % 1 1 0 2 3 0 Mvmt Flow 569 131 8 681 105 12 Major/Minor Major1 Major2 Minor1 Conflicting Flow All 0 0 700 0 1332 635 Stage 1 - - - - 635 - Stage 2 - - - - 697 - Critical Hdwy - - 4.1 - 6.43 6.2 Critical Hdwy Stg 1 - - - - 5.43 - Critical Hdwy Stg 2 - - - - 5.43 - Follow-up Hdwy - - 2.2 - 3.527 3.3 Pot Cap-1 Maneuver - - 906 - 169 482 Stage 1 - - - - 526 - Stage 2 - - - - 492 - Platoon blocked, % - -- Mov Cap-1 Maneuver - - 906 - 167 482 Mov Cap-2 Maneuver - - - - 167 - Stage 1 - - - - 526 - Stage 2 - - - - 485 - Approach EB WB NB HCM Control Delay, s 0 0.1 56.8 HCM LOS F Minor Lane/Major Mvmt NBLn1 EBT EBR WBL WBT Capacity (veh/h)179 - - 906 - HCM Lane V/C Ratio 0.655 - - 0.008 - HCM Control Delay (s) 56.8 - - 9 0 HCM Lane LOS F - - A A HCM 95th %tile Q(veh)3.8 - - 0 - 572 of 628 Updated Transportation Impact Analysis Carbon Trails Residential Appendix C Detailed Trip Generation Calculations 573 of 628 ITE Land Use Units 1 LUC 2 In Out Trip Rate 2 In Out Total Weekday Daily Proposed Use: Single-Family Homes 44 DU 210 50%50%EQN 245 244 489 Less Existing Use: Single-Family Home 1 DU 210 50%50%9.44 -5 -4 -9 Net New Daily Trips = 240 240 480 Weekday AM Peak Hour Proposed Use: Single-Family Homes 44 DU 210 25%75%EQN 9 27 36 Less Existing Use: Single-Family Home 1 DU 210 25%75%0.74 0 -1 -1 Net New AM Peak Hour Trips = 9 26 35 Weekday PM Peak Hour Proposed Use: Single-Family Homes 44 DU 210 63%37%EQN 29 17 46 Less Existing Use: Single-Family Home 1 DU 210 63%37%0.99 -1 0 -1 Net New PM Peak Hour Trips = 28 17 45 Notes: 1. DU = Dwelling Units. 2. Land use Code and trip rates based on ITE Trip Generation Manual, 10th edition, 2017. Carbon Trails Residential Trip Generation Summary Directional Distribution Trips Generated 7/16/2020 574 of 628 18355.005.docx Carbon Trails Preliminary Plat Application Auburn, Washington Parcels: 926280-0295, 926280-0320, 926280-0313 School Access Analysis: This proposed plat lies within the City of Auburn and the Auburn School District. The students from the proposed homes will attend Evergreen Heights Elementary School, Cascade Middle School, and Auburn High School. The Auburn School District Transportation Department website was utilized to verify the bus stop locations for the proposed plat. There is currently a bus stop at 56th Avenue South and South 328th Street, at the east end of the project and one at 46th Place South and 51st Avenue South at the west end of the project. Currently the walking distance between the intersection of 51st Ave South and South 328th and the western bus stop is approximately 0.25 miles. The distance between 51st Avenue South and 56th Avenue South is also approximately 0.25 miles. This would be approximately the longest distance that students would need to walk to get to their bus stop location. Per the included maps, none of the proposed plat is within a walkable distance to a nearby school. All students would ride a bus to their prospective schools from one of these two existing bus stops. The plat proposal includes sidewalks on both sides of South 328th Street to provide pedestrian access. Student from this development would need to go to the bus stop at 56th Avenue South to maintain a safe walking route. Students do not have a safe walking route to the bus stop at 46th Place South and 51st Avenue South, 51st Avenue South does not have an existing sidewalk; therefore this stop should not be used by students in this development. The one lot that fronts 56th Avenue South has access to an existing sidewalk on the east side of 56th Avenue South to the bus stop location. The Auburn School District Transportation Department was contacted and they confirmed the proposed development would utilize the existing bus stop at South 328th Street and 56th Avenue South. Evergreen Heights Elementary Approximately 0.8-1.3 miles from the site via 56th Avenue South Cascade Middle School Approximately 4.2-4.4 miles from the site Auburn High School Approximately 2.7-3 miles from the site 575 of 628 1 Karen Harris From:Yanez, Jennifer <jyanez@auburn.wednet.edu> Sent:Monday, April 5, 2021 9:03 AM To:Karen Harris Cc:Jason Hubbell Subject:RE: Bus Stop for Proposed Carbon Trails development BCE #18355 Follow Up Flag:Follow up Flag Status:Flagged Karen, Yes, based on the maps the stop for this new development would be located at the existing stop at S 328th St and 56th AVE S. Best wishes on your project. Please let me know if I can be of further assistance. Regards, Jennifer Yanez Auburn School District Router/Dispatcher (253) 931-4938 From: Karen Harris <kharris@barghausen.com> Sent: Monday, April 5, 2021 7:48 AM To: Yanez, Jennifer <jyanez@auburn.wednet.edu> Cc: Jason Hubbell <jhubbell@barghausen.com> Subject: RE: Bus Stop for Proposed Carbon Trails development BCE #18355 This email originated outside of the organization and contains a Web link or attachment. Please use caution. – ASD Tech Jennifer- Have you had a chance to look at this project? Thanks, Karen Karen E. Harris, P.E. | Senior Project Engineer Office: 425-251-6222 | Direct: 425-656-7470 Barghausen Consulting Engineers, Inc. 18215 72nd Avenue South, Kent WA 98032 www.barghausen.com From: Karen Harris Sent: Tuesday, March 30, 2021 2:18 PM To: 'jyanez@auburn.wednet.edu' <jyanez@auburn.wednet.edu> 576 of 628 2 Cc: Jason Hubbell <jhubbell@barghausen.com> Subject: Bus Stop for Proposed Carbon Trails development BCE #18355 Jennifer- Attached is a few pages from the Carbon Trails preliminary plat showing the location of the plat and the proposed sidewalks. Please let me know if you need anything else in order to evaluate this project for a bus stop. Thanks, Karen Karen E. Harris, P.E. | Senior Project Engineer Office: 425-251-6222 | Direct: 425-656-7470 Barghausen Consulting Engineers, Inc. 18215 72nd Avenue South, Kent WA 98032 www.barghausen.com 577 of 628 n n n n nn nn n n n n n n n n n n n n n n SR1678TH VALLEY122ND9TH 2NDJOVITA 114TH36TH112TH 16TH EAST VALLEYWEST VALLEY18TH ISLAND182ND 214TH179THEDWARDS DIKE 12TH 4TH 18 5 T H 142ND69TH 198THSTEWART 136THROY 190THSUMNER-TAPPS17THLAKELAND H ILLS LA K E T A P P S 1 8 6 T H 140THCOUNTY LINE 26TH24TH67THBUTTE 166TH126TH34TH A 108TH25T H 1ST FOREST CANYONEVERGREEN118TH 5 TH 110TH200TH3RD 19 6 T H DRIFTWO O D 2 1 1 TH199TH64THOLIVE13TH 2 1 0 T H 29TH 2 0 8 TH 21STTHOMAS 32ND 14TH203RD20TH119TH1 8 4 T H 2 0 6 TH 220T H 1 5 6 T H 23RD 205TH62ND 73RD 35TH 132ND33 R D 27TH E LA INE117TH 6TH CHARLOTTE17 0 T H121ST 31ST 10TH123RD7TH202ND 71ST 111TH178TH29T H 34TH126TH24TH 184TH110TH12TH VALLEY29TH 24TH SR16721ST 5TH SR 18SR 167SE 416TH ST SE 272ND ST SE 400TH STA ST SESE GREEN VALLEY RDC ST SWAU B U R N W A Y SMIL ITARY RD SB ST NWM ST SES 277TH ST SE 384TH STI ST NE3RD AVE124TH AVE SE244TH AVE SEAUBURN WAY N132ND AVE SER ST SESE AUBURN-BL A C K D I A M O N D R D 180TH AVE SE212TH AVE SE236TH AVE SEAUBURN- ENUMC LAW RD SE264TH AVE SEE MAIN ST WEST VALLEY HWY SSTUCK RIVER DR THOMAS RD SESE 288TH ST 208TH AVE SEWEST VALLEY HWY NS 288TH ST 15TH ST SW C ST NE15TH ST NW 278TH WAY SEW MAIN ST SE 380TH ST116TH AVE SEC ST NW55TH AVE SELLINGSON RD 29TH ST SE 53RD ST SE S 352ND ST 212TH WAY SEKE N T - B L A C K D I A M O N D R D S E 17TH ST SE 1ST AVE S 2 1 8TH AVE SE 41ST ST SE ROBERTS DR RAMP ORAVETZ RDM ST NWS 360TH ST M ST NEENUMCLAW-FRANKLIN RD SE8TH ST NE S 298TH ST 3RD AVE SE 37TH ST SE SE 376TH ST SE COVINGTON- S A W Y E R R D SE 346TH ST154TH AVE SESE WAX RD4 6 TH P L S196TH AVE SE37TH ST NW SE 276TH ST SE 284TH ST S STAR LAKE RD SE 304TH ST 104TH AVE SESE LAKE HOLM RD S 368TH ST 1ST AVE E 268TH AVE SE200TH AVE SESE 392ND ST SE 358 T H S TB ST SE44TH AVE SK E R S E Y W A Y 49TH AVE SSE 312TH ST 25TH ST SEMA IN S T S 296TH ST 257TH AVE SE249TH AVE SE4TH ST NE SE DIAMOND DRLAWSON STSE 277TH ST 207TH AVE SESE 368TH STD ST NWD ST SE110TH AVE SEA ST NES C E N I C D R 188TH AVE SE108TH AVE SE51ST AVE SSE 278TH STGREEN R IVER RD 55TH ST SE SE 400TH WAYSE 274TH ST 144TH AVE SE258TH AVE SE3RD AVE SW 118TH AVE SES 308TH ST S 356TH ST 16 0 T H P L S E 170TH AVE SE22 8TH AVE SE38TH AVE S254TH AVE SESE 3 5 4 T H S T SE 299TH STD ST NES 364TH ST E ST NE42ND AVE SO ST NESE 368TH P L152ND AVE SES 321ST ST S 287TH ST S 316TH ST 1S T A V E 3RD AVE S 172ND AVE SEH O W A R D R D 232ND AVE SE201ST PL SE4TH AVE N S 300TH PL SE 326TH ST SE 394TH ST168TH PL SE202ND AVE SESE 388TH ST164TH PL SES 372ND ST MILL POND DR157TH PL SE112TH AVE SESE 353RD ST 210TH AVE SEABRAMS AVE162ND AVE SESE 387TH ST SE 320TH ST SE 331ST ST 204TH AVE SE176TH AVE SEW ST NW181ST AVE SESE 281ST ST 160TH AVE SE171ST AVE SE278TH AVE SE4TH ST SE 192ND AVE SE33RD ST SE 4TH AVE SW5TH AVE SW S 280TH ST 250TH AVE SE56TH PL SBRIDGET AVE SESE 408TH STSE 328TH PL219TH WAY SESE 282ND ST 206TH AVE SEDOGWOOD ST SEPIKE ST NEBOUNDARY BLVD SE LAKE GINDER RD S 331ST ST SE 340TH STH ST SE52ND AVE SSE 330T H W A Y65TH AVE SS E 3 1 2 T H W A Y SE 296TH ST SE 410TH ST 56TH ST SE SE 280TH ST54TH AVE SSE 310TH ST U ST NW SE 290TH ST 217TH AVE SESE 364TH ST SE 344TH ST 35TH WAY SE 260TH AVE SESE 323RD PL SE 322ND ST SE 318TH W A Y SE 380TH LN SE 403RD ST SE 298TH PL 245TH AVE SESE 287TH S T S 284TH PL 235TH AVE SESE 373RD ST37TH AVE S1 5 8 TH AVE SE SE 352ND ST HEMLOCK ST SES 354TH ST SE 276TH PL 148TH AVE SESE 283RD ST S 294TH ST SE 275TH ST SE 278TH WAY SE 279TH ST SE 323RD ST SE 318TH ST 42ND ST NW 178TH AVE SESE 367TH W A Y 28TH ST NE 17 0 T H P L S E 186TH PL SESE 300TH PL SE 294TH PLSE 295 T H S T SE 332ND P L 2ND ST SE SE 271ST ST SE 409TH ST SE 371ST ST S 290TH ST 234TH AVE SE SE 372ND ST SE 324TH ST 164TH AVE SESE 286TH ST S 362ND ST 185TH AVE SE248TH AVE SE252ND AVE SE276TH AVE SE40TH ST NE SE 354TH PLL ST NE286TH AVE SESE 357TH STE ST SESE 297TH ST 21ST ST SE 3RD ST SW 12TH ST NE SE 279TH PLRAMPSE 281ST ST SR 18SE LAKE HOLM RD SE 286TH ST SE 384TH STRAMP112TH AVE SERAMP202ND AVE SESE 368TH ST RAMP SE 284TH STSR 167SE 274TH ST SE 304TH ST RAMPSR 1842ND AVE S200TH AVE SE218TH AVE SERAMPSE 276TH ST 218TH AVE SE188TH AVE SE192ND AVE SESE 276TH ST 188TH AVE SERAMPSE 376TH ST SE 394TH ST152ND AVE SE212TH AVE SE55TH AVE SRAMP164TH AVE SE55TH AVE S108TH AVE SESE 304TH ST SE 344TH ST Auburn School District Elementary School Attendance Area / Legend n Auburn Schools Alpac Arthur Jacobsen Chinook Dick Scobee Evergreen Heights Gildo Rey Hazelwood Ilalko Lake View Lakeland Lea Hill Pioneer Terminal Park Washington Lakes & Rivers Produced by: Auburn School District # 408 - November 2016 Lake View ES Arthur Jacobsen ES Lea Hill ES Hazelwood ES Chinook ES Lakeland Hills ES Ilalko ES Alpac ES Gildo Rey ES Pioneer ES Evergreen Heights ES Dick Scobee ES Washington ES Terminal Park ESProject Site 578 of 628 n nn n n n n nnSR 167SR 18 B ST NWS 277TH ST I ST NEAUBURN WAY NM ST SEC ST SWRAMPMILITARY RD SA ST SE68TH AVE S72ND AVE SE MAIN STWEST VALLEY HWY N15TH ST SW GR E E N R I V E R R D C ST NE15TH ST NW W MAIN ST C ST NW55TH AVE S78TH AVE S AU B U R N W A Y S S 288TH ST 17TH ST SEO STM ST NW21ST ST SEM ST NES 259TH ST 8TH ST NE S 352ND ST WEST VALLEY HWY S4 6 TH P L S 37TH ST NW 22ND ST NE B ST SE44TH AVE S25TH ST SE S 272ND ST S 296TH ST S PEASLEY CANYON RD 12TH ST SE S 298TH ST S STAR LAKE RD 4TH ST NECENTRAL AVE S30TH ST NED ST NWH ST NWCLAY STEMERALD DOWNS DRA ST NE94TH PL SLAKE FENWICK RD S4TH ST SE51ST AVE SREITH RDS 308TH ST CELERY AVEGREEN RIVER RD SED ST NEE ST NEN ST NEO ST NE37TH ST NE 9 7 T H P L S S 321ST ST S 287TH ST52ND LN SS 316TH ST H A R V E Y R D S 300 T H P L 44TH ST NW46TH AVE S14TH ST NE39TH AVE S5 1 S T P L S ALGONA BLVD NE MAPLE STE WALNUT ST 38TH AVE SS 261ST ST R ST SE45TH PL SW ST NWS 340TH ST 6TH AVE N K ST SES 280TH ST 79TH AVE SS 301ST DR 29TH ST NW S 342ND ST 5TH ST SE1ST AVE SD ST SE8TH ST SE48TH AVE SPIKE ST NEA ST SWS 279TH ST 3RD AVE SF ST SEL ST SEBOUNDARY BLVD S 331ST ST 32ND PL NE H ST SES 338TH ST SUPERMALL WAY G ST SES 2 7 2 N D W A Y 52ND AVE SS 262ND ST LUND RD65TH AVE S15TH ST NE S 336TH ST54TH AVE S57TH PL S74TH AVE S53RD AVE SU ST NWHI CREST DR85TH AVE SS 349TH ST S 305TH ST 58TH AVE SHAMPTON WAY NE 51ST ST J ST SER ST NW31ST ST NE 26TH ST SE HOWA R D R D41ST PL SS 300TH ST EAST VALLEY HWY S10TH ST NE B ST NE7TH ST SEV ST NW23RD ST SEN ST SE49TH AVE SMAPLE LN S2ND ST NW5TH AVE SW O O D L A N D W A Y 24TH ST SE S 318TH ST CARNABY WAY H ST NES 292ND ST 22ND ST SEPIKE ST NW42ND ST NW A ST NW42ND AVE S28TH ST NE F ST N W 49TH ST NE S 354TH ST 6TH ST NW S 320TH ST L PL SET ST SE2ND ST SE S 273RD PL 3RD ST NW S 285TH ST 56TH AVE SS 344TH ST 40TH ST NE 40TH PL SPARK AVE HEMLOCK ST 52ND PL SS 266TH ST 40TH AVE S1ST ST SW C ST SES 262ND PL 10TH AVE N 26TH ST NE 15TH ST SE S 303RD PL J ST NE24TH ST NE S 263RD ST 45TH ST NE S 256TH ST 30TH ST NW 57TH AVE S47TH AVE SAABY DRR PL NE41ST AVE S3RD ST SW59TH AVE S61ST AVE S8TH ST SW S 282ND W A Y S 347TH ST42ND PL S45TH WAY SCHICAGO AVEO ST SE50TH AVE SS 274TH PL 66TH AVE S16TH ST NW R ST NE63RD PL SS 258TH PL S 296TH PL 2ND ST NE43RD AVE SIVES AVES 284TH ST CEDAR DR S 329TH PL S 346TH ST S 277TH PL 99TH PL SS 314TH STC PL SE19TH ST SE53RD PL SS 297 T H P L S 257TH ST 29TH ST NW RAMP55TH AVE S47TH AVE SS 342ND ST R ST NW47TH AVE S42ND PL SS 262ND ST RAMPSR 167RAMP RAMPRAMPI ST NE51ST AVE SRAMPRAMP 55TH AVE SO ST NER ST NW57TH PL S42ND AVE SRAMP PIKE ST NW S 262ND ST S 296TH PL RAMP51ST AVE SF ST SE26TH ST NE D ST SE26TH ST SE41ST PL S8TH ST NE PIKE ST NES 292ND STA ST SESR 18 SR 167SR 18M ST NE44TH AVE SEvergreen Heights Elementary School Attendance Area Produced by: Auburn School District # 408 - November 2016 Legend Evergreen Heights Evergreen Heights Walk Boundary Auburn School District Boundary Lakes & Rivers / Evergreen Heights ES Project Site 579 of 628 nm nm nm nmnmnm nmnm nm nm nm nm nm nm nm nmnm nm nm nm nm nm SR 18SR 167SE 400TH STA ST SESE GREEN VALLEY RD MILITARY RD SSE 416TH STI-5 FRWYC ST SWAU B U R N W A Y SB ST NWM ST SESE 384TH STI ST NE3RD AVE244TH AVE SE124TH AVE SEAUBURN WAY NR ST SE132ND AVE SE180TH AVE SES 288TH ST 212TH AVE SE236TH AVE SEA U B U R N - E N U M C L A W R D S E 264TH AVE SEE MAIN ST WEST VALLEY HWY SSTUCK RIVER DR THOMAS RD SE SE 288TH ST 208TH AVE SES 360TH ST WEST VALLEY HWY NENUMCLAW-FRANKLIN RD SE15TH ST SW 292ND AVE SEC ST NERAMP15TH ST NW W MAIN ST SE 380TH ST116TH AVE SEC ST NW278TH WAY SE55TH AVE SELLINGSON RD 29TH ST SE34TH AVE S53RD ST SE32ND AVE SS 352ND ST 212TH WAY SEKE N T - B L A C K D I A M O N D R D S E 1ST AVE S S 298TH ST 2 1 8TH AVE SE 41ST ST SE ROBERTS DR ORAVETZ RDM ST NWM ST NE8TH ST NE 3RD AVE SE SE 376TH ST SE 346TH ST154TH AVE SE4 6 TH P L S 196TH AVE SESE 276TH ST SE 284TH ST 290TH AVE SESE 304TH ST SE LAKE HOLM RD 1ST AVE E 200TH AVE SESE 392ND ST 268TH AVE SESE 358 T H S TB ST SE44TH AVE SK E R S E Y W A Y 49TH AVE SS 356TH ST SE 312TH ST MA IN S T 2 4 9TH AVE SE 4TH ST NE SE DIAMOND DRLAWSON STSE 277TH ST 207TH AVE SESE 368TH ST S 320TH ST D ST NW110TH AVE SES C E N I C D R 188TH AVE SE51ST AVE SSE 278TH ST 55TH ST SE SE 400TH WAY144TH AVE SE258TH AVE SE118TH AVE SES 308TH ST SE 342ND ST 16 0 T H P L S E170TH AVE SE38TH AVE S254TH AVE SESE 3 5 4 T H S T SE 299TH ST E ST NE42ND AVE SSE 368TH P L COUNTY LINE RD E 108TH AVE SES 316TH ST 228TH AVE SE 3RD AVE S 194TH AVE SEH O W A R D R D 201ST PL SES 300TH PL SE 326TH ST 202ND AVE SESE 388TH ST164TH PL SES 372ND ST MILL POND DR157TH PL SE22 8 T H W A Y S E112TH AVE SESE 353RD ST 210TH AVE SES 364TH ST SE 387TH ST SE 331ST ST 204TH AVE SE176TH AVE SE181ST AVE SESE 281ST ST 160TH AVE SE278TH AVE SE4TH ST SE 192ND AVE SE5TH AVE SW S 280TH ST 8TH ST SE 219TH WAY SE206TH AVE SEDOGWOOD ST SEF ST SESE 340TH ST SE 330T H W A Y65TH AVE SSE 296TH S T 56TH ST SE SE 280TH ST SE 290TH ST HI CRES T DR217TH AVE SE47TH ST SE S 349TH ST SE 306TH ST 58TH AVE SSE 364TH ST NE 51ST ST SE 344TH ST 35TH WAY SEJ ST SESE 323RD PL CHUB LAKE RDSE 3 2 2 N D S T SE 318TH W A Y 26TH ST SE KANAS K E T D R SE 287TH ST S 284TH PL 235TH AVE SE1 5 8 TH AVE SE SE 352ND ST SE 283RD ST S 294TH ST 216TH AVE SE164TH AVE SES 344TH ST S 368TH ST SE 277TH PL SE 380TH ST SE 376TH STRAMPSE 368TH ST SE 276TH ST RAMPSE 28 1 S T S T SR 167192ND AVE SESE 331ST ST 180TH AVE SESE 384TH ST RAMP SE 276TH ST SE 344TH STSR 18200TH AVE SE218TH AVE SE55TH AVE SSE LAKE HOLM RD ² Auburn School District Middle School Attendance Area Legend nm Auburn Schools Cascade Mt. Baker Olympic Rainier Produced by: Auburn School District # 408 - November 2016 Mt. Baker MS Cascade MS Olympic MS Rainier MS Project Site 580 of 628 nm nm nm nmnmnm nmnm nm nm nm nm nm nm nm nm nm nm nm nm nm nm SR 18SR 167A ST SESE GREEN VALL E Y R D C ST SWAU B U R N W A Y SB ST NWM I L I T A R Y R D S M ST SES 277TH ST SE 384TH STI ST NE3RD AVE124TH AVE SEAUBURN WAY N132ND AVE SER ST SESE AUBURN-BL A C K D I A M O N D R D E MAIN ST WEST VALLEY HWY SSTUCK RIVER DR THOMAS RD SESE 288TH ST 208TH AVE SEWEST VALLEY HWY N15TH ST SW S 288TH ST C ST NE15TH ST NW 200TH AVE SEW MAIN ST SE 380TH ST116TH AVE SEC ST NW244TH AVE SE55TH AVE SELLINGSON RD 29TH ST SE 53RD ST SE 212TH WAY SEKE N T - B L A C K D I A M O N D R D S E S 352ND ST 17TH ST SE 1ST AVE S 2 1 8TH AVE SE 41ST ST SE ROBERTS DR ORAVETZ RDM ST NWM ST NE8TH ST NE RAMP 3RD AVE SE SE 376TH ST S 360TH ST SE COVINGTON- S A W Y E R R D SE 346TH ST154TH AVE SE4 6 TH P L S 196TH AVE SES 298TH ST SE 276TH ST SE 284TH ST SE WAX RDSE 304TH ST 104TH AVE SESE LAKE HOLM RD S 368TH ST 1ST AVE E SE 392ND ST SE 358 T H S T44TH AVE SK E R S E Y W A Y 49TH AVE SSE 312TH ST 25TH ST SEMA IN S T 257TH AVE SE249TH AVE SE12TH ST SE 4TH ST NE SE DIAMOND DRLAWSON STSE 277TH ST SE 368TH STD ST NWD ST SE110TH AVE SEA ST NES C E N I C D R 188TH AVE SE51ST AVE SSE 278TH ST 55TH ST SE 144TH AVE SE108TH AVE SE118TH AVE SEGREEN R IVER RD 16 0 T H P L S E 170TH AVE SE38TH AVE SSE 3 5 4 T H S T SE 299TH ST D ST NES 364TH ST 42ND AVE SSE 368TH P L COUNTY LINE RD E 180TH AVE SES 287TH ST 1 S T A V E 3RD AVE S 201ST PL SES 300TH PL SE 326TH ST WEST VALLEY HWY46TH AVE S202ND AVE SESE 388TH ST164TH PL SEMILL POND DR157TH PL SE112TH AVE SESE 353RD ST 210TH AVE SEABRAMS AVE162ND AVE SESE 320TH ST SE 331ST ST 204TH AVE SE176TH AVE SEW ST NW23 6 T H A V E S E181ST AVE SES 340TH ST SE 281ST ST 160TH AVE SE171ST AVE SE4TH ST SE 192ND AVE SE5TH AVE SW56TH PL SBRIDGET AVE SESE 328TH PL8TH ST SE 219TH WAY SE206TH AVE SEF ST SEBOUNDARY BLVD SE 340TH ST SE 330T H W A Y65TH AVE SS E 3 1 2 T H W A Y 207TH PL SESE 296TH ST 56TH ST SE SE 280TH ST U ST NW217TH AVE SE85TH AVE SKE R S E Y W A Y SKYWAY LN S 349TH ST SE 364TH ST SE 344TH ST 35TH WAY SE SE 323RD PL SE 298TH PL KANAS K E T D R SE 287TH S T 235TH AVE SESE 373RD ST 1 5 8 TH AVE SE SE 352ND ST SE 276TH PL SE 283RD ST S 294TH ST SE 275TH ST 228TH AVE SE SE 278TH WAY SE 323RD ST SE 318TH ST 28TH ST NE 17 0 T H P L S E 186TH PL SESE 300TH PL SE 295TH ST SE 332ND P L S 290TH ST SE 378TH ST 234TH AVE SE SE 372ND ST SE 324TH ST 164TH AVE SET ST NE252ND AVE SE56TH AVE S37TH AVE S12TH ST NE 164TH AVE SESE LAKE HOLM RD SE 384TH ST SE 380TH ST55TH AVE S192ND AVE SEM ST NESE 28 1 S T S T SE 276TH STRAMP SE 288TH ST SE 376TH ST SE 392ND ST SE 368TH ST RAMP SR 18 SE 392ND ST SE 344TH ST 38 T H A V E S SE 281ST ST SE 372ND ST RAMP RAMPSE 288TH STSR 167SR 18 SE 392ND ST SE 284TH ST ² Cascade Middle School Attendance Area Produced by: Auburn School District # 408 - November 2016 Legend Cascade Cascade Walk Boundary Auburn School District Boundary Lakes & RiversCascade MS Project Site 581 of 628 nm nm nm nmnmnm nmnm nm nm nm nm nm nm nm nm nm nm nm nm nm nm SR 18SR 167SE 400TH STA ST SESE GREEN VALLEY RDMIL ITARY RD SI-5 FRWYC ST SWAU B U R N W A Y SB ST NWM ST SESE 416TH ST SE 384TH STI ST NE3RD AVE244TH AVE SEAUBURN WAY N124TH AVE SER ST SE132ND AVE SE180TH AVE SES 288TH ST 212TH AVE SE236TH AVE SEA U B U R N - E N U M C L A W R D S E E MAIN ST 264TH AVE SEWEST VALLEY HWY SSTUCK RIVER DR THOMAS RD SE SE 288TH ST 208TH AVE SEWEST VALLEY HWY NS 360TH ST 15TH ST SW ENUMCLAW-FRANKLIN RD SEC ST NE15TH ST NW W MAIN ST SE 380TH ST116TH AVE SEC ST NW278TH WAY SE55TH AVE SELLINGSON RD 29TH ST SE34TH AVE S53RD ST SE32ND AVE SS 352ND ST 212TH WAY SEKE N T - B L A C K D I A M O N D R D S E 1ST AVE S S 298TH ST 2 1 8TH AVE SE 41ST ST SE ROBERTS DR ORAVETZ RDM ST NWM ST NE8TH ST NE RAMP3RD AVE SE SE 376TH ST SE 346TH ST154TH AVE SE4 6 TH P L S 196TH AVE SE37TH ST NW SE 276TH ST SE 284TH ST SE 304TH ST SE LAKE HOLM RD S 368TH ST 1ST AVE E 200TH AVE SESE 392ND ST SE 358 T H S TB ST SE268TH AVE SE44TH AVE SK E R S E Y W A Y 49TH AVE SS 356TH ST SE 312TH ST MA IN S T 2 4 9TH AVE SE 4TH ST NE SE DIAMOND DRLAWSON STSE 277TH ST 207TH AVE SESE 368TH STD ST NW110TH AVE SES C E N I C D R 188TH AVE SE51ST AVE SSE 278TH ST 55TH ST SE SE 400TH WAY144TH AVE SE258TH AVE SE118TH AVE SES 308TH ST SE 342ND ST 16 0 T H P L S E170TH AVE SE38TH AVE S254TH AVE SESE 3 5 4 T H S T SE 299TH ST E ST NE42ND AVE SSE 368TH P L COUNTY LINE RD E S 316TH ST 3RD AVE S 194TH AVE SE228TH AVE SE H O W A R D R D 201ST PL SES 300TH PL 108TH AVE SE292ND AVE SESE 326TH ST 202ND AVE SESE 388TH ST164TH PL SES 372ND ST MILL POND DR157TH PL SE22 8 T H W A Y S E112TH AVE SESE 353RD ST 210TH AVE SES 364TH ST SE 387TH ST SE 331ST ST 204TH AVE SE176TH AVE SE181ST AVE SESE 281ST ST 160TH AVE SE278TH AVE SE4TH ST SE 192ND AVE SE5TH AVE SW S 280TH ST 5TH ST SE8TH ST SE 219TH WAY SE206TH AVE SEDOGWOOD ST SEF ST SESE 340TH ST SE 330T H W A Y65TH AVE SSE 296TH S T 56TH ST SE SE 280TH ST SE 290TH ST HI CRES T DR217TH AVE SE47TH ST SE S 349TH ST S 305TH ST SE 306TH ST 58TH AVE SSE 364TH ST SE 344TH ST 35TH WAY SEJ ST SESE 323RD PL CHUB LAKE RDSE 3 2 2 N D S T SE 318TH W A Y 26TH ST SE KANAS K E T D R SE 287TH ST S 284TH PL 235TH AVE SE37TH AVE S1 5 8 TH AVE SE SE 352ND ST HEMLOCK ST SESE 283RD ST S 294TH ST SE 323RD ST216TH AVE SE164TH AVE SE185TH AVE SE S 344TH ST 200TH AVE SESE 376TH ST SE 276TH ST SE 344TH STRAMP RAMPSE 380TH ST SE 284TH ST 32ND AVE S180TH AVE SESE 276TH ST SR 167SE 384TH ST SE 331ST ST 55TH AVE SRAMP RAMP SR 18 SE 368TH ST 218TH AVE SESE LAKE HOLM RDRAMP ² Auburn School District High School Attendance Area Legend Auburn High School Auburn Riverside HS Auburn Mountainview HS Produced by: Auburn School District # 408 - November 2016 Auburn Riverside HS Auburn High School Auburn Mountainview HS Project Site 582 of 628 nm nm nm nmnmnm nmnm nm nm nm nm nm nm nm nm nm nm nm nm nm nm SR 18SR 167SE 400TH STA ST SESE GREEN VALLEY RD MILITARY RD SI-5 FRWYC ST SWSE 416TH ST AU B U R N W A Y SB ST NWM ST SESE 384TH STI ST NE3RD AVE244TH AVE SEAUBURN WAY N124TH AVE SER ST SE132ND AVE SE180TH AVE SES 288TH ST 212TH AVE SE236TH AVE SEA U B U R N - E N U M C L A W R D S E 264TH AVE SEE MAIN ST WEST VALLEY HWY SSTUCK RIVER DR THOMAS RD SE SE 288TH ST 208TH AVE SES 360TH ST WEST VALLEY HWY N15TH ST SW ENUMCLAW-FRANKLIN RD SEC ST NE15TH ST NW W MAIN ST SE 380TH ST116TH AVE SEC ST NW278TH WAY SE55TH AVE SELLINGSON RD 29TH ST SE34TH AVE S53RD ST SE32ND AVE SS 352ND ST 212TH WAY SEKE N T - B L A C K D I A M O N D R D S E 1ST AVE S S 298TH ST 2 1 8TH AVE SE 41ST ST SE ROBERTS DR ORAVETZ RDM ST NWM ST NE8TH ST NE 3RD AVE SE SE 376TH ST SE 346TH ST154TH AVE SE4 6 TH P L S 196TH AVE SE37TH ST NW SE 276TH ST SE 284TH ST SE 304TH ST SE LAKE HOLM RD 1ST AVE E 200TH AVE SESE 392ND ST SE 358 T H S T 268TH AVE SEB ST SE44TH AVE SK E R S E Y W A Y 49TH AVE SS 356TH ST SE 312TH ST MA IN S T 2 4 9TH AVE SE 4TH ST NE SE DIAMOND DRLAWSON STSE 277TH ST 207TH AVE SESE 368TH STD ST NW110TH AVE SES 320TH ST S C E N I C D R 188TH AVE SE51ST AVE SSE 278TH ST 55TH ST SE SE 400TH WAY144TH AVE SE258TH AVE SE118TH AVE SES 308TH ST SE 342ND ST 16 0 T H P L S E170TH AVE SE38TH AVE S254TH AVE SESE 3 5 4 T H S TRAMPSE 299TH ST E ST NE42ND AVE SSE 368TH P L COUNTY LINE RD E S 316TH ST 3RD AVE S 194TH AVE SE228TH AVE SE H O W A R D R D 201ST PL SES 300TH PL SE 326TH ST108TH AVE SE202ND AVE SESE 388TH ST164TH PL SES 372ND ST MILL POND DR157TH PL SE22 8 T H W A Y S E112TH AVE SESE 353RD ST 292ND AVE SE210TH AVE SES 364TH ST SE 387TH ST SE 331ST ST 204TH AVE SE176TH AVE SE181ST AVE SESE 281ST ST 160TH AVE SE278TH AVE SE4TH ST SE 192ND AVE SE5TH AVE SW S 280TH ST 5TH ST SE8TH ST SE 219TH WAY SE206TH AVE SEDOGWOOD ST SEF ST SESE 340TH ST SE 330T H W A Y65TH AVE SSE 296TH S T 56TH ST SE SE 280TH ST SE 290TH ST HI CRES T DR217TH AVE SE47TH ST SE S 349TH ST S 305TH ST SE 306TH ST 58TH AVE SSE 364TH ST SE 344TH ST 35TH WAY SEJ ST SESE 323RD PL CHUB LAKE RDSE 3 2 2 N D S T SE 318TH W A Y 26TH ST SE KANAS K E T D R SE 287TH ST S 284TH PL 235TH AVE SE1 5 8 TH AVE SE SE 352ND ST HEMLOCK ST SESE 283RD ST S 294TH ST SE 323RD ST216TH AVE SE164TH AVE SE185TH AVE SE S 344TH ST S 368TH ST 200TH AVE SESE 380TH ST S 316TH S T RAMPSE LAKE HOLM RD RAMP RAMP196TH AVE SESE 276TH ST RAMP RAMPSE 376TH STSR 167SE 331ST ST SE 384TH ST180TH AVE SESR 18 SE 344TH ST SE 368TH ST55TH AVE SSE 284TH ST 218TH AVE SESE 276TH ST ² Auburn High School Attendance Area Legend Auburn High School AHS Walk Boundary Auburn School District Boundary Lakes & Rivers Produced by: Auburn School District # 408 - November 2016 Auburn High School Project Site 583 of 628 October 7, 2021 Shannon Howard, P.E. CFM Development Review Engineer Department of Community Development City of Auburn 1 East Main Street Auburn, WA 98001 RE: Request for Deviation (DEV21-0035) for Wall Located in Right-of-Way, on East End of South 328th Street Carbon Trails Preliminary Plat PLT19-0002 SEP19-0003 Our Job No. 18355 Dear Shannon: We are requesting a General Deviation from the City of Auburn EDS Section 5.04 and 10.01.03 for the above-referenced project. The deviation consists of locating a retaining wall within a portion of the city- owned South 328th Street Right-of-Way to achieve the required 2:1 maximum backslope. The deviation is being requested due to slope limitations that limit grading activities within the right-of-way needed to provide a public sidewalk on the south side of South 328th Street. BACKGROUND INFORMATION The proposed project is to develop three parcels in Auburn for a single-family residential plat. The three parcels are approximately 11.4 acres combined. The project is located within Section 14, Township 21 North, Range 4 East, Willamette Meridian, City of Auburn, King County, Washington. More particularly, the site is located between 51st and 56th Avenue South at South 328th Street. The site lies within a single-family zoned area. A lot of the area is still rural-type homes with large lots, but there are parcels to the south and east that have been developed into small subdivisions. One of the parcels being developed is 32727 56th Avenue South, Auburn, WA 98001. Assessor parcel numbers are 926280-0320, -0295 and -0313. The current zoning is R-5 residential. The proposal is to create approximately 44 single-family lots for development. The project would include platting, road improvements, utility extensions, storm drainage conveyance, water quality and detention to meet the City of Auburn requirements. The residential plat would meet the current R-5 zoning, including minimum lot sizes, setbacks, and impervious surface coverage. The proposed single-family homes would likely be in the 2,500-3,500-square-foot range with fenced yards and appropriate landscaping and street trees. This project site has a significant grade difference between existing grade within the right-of-way of South 328th Street and the developed roadway 56th Avenue South. The justification for requesting the retaining wall in the right-of-way is as follows per City Engineering Design Standards 1.04.1: 584 of 628 Shannon Howard, P.E. CFM Development Review Engineer Department of Community Development City of Auburn -2- October 7, 2021 JUSTIFICATION A. The functional intent of the design element: The retaining wall is proposed within the right-of-way due to limited right-of-way to perform grading necessary for 2:1 slope from the back of the new sidewalk down to the existing grade to the south. The project developer has been in contact with private property owner (parcel 92628002322) regarding a grading easement, but the owner has recently passed away, and surviving family members are not willing or able to provide the necessary grading easement on this property. B. Safety factors associated with the design element: The wall has been located near the back of the sidewalk to minimize/eliminate slopes adjacent to the pedestrian walkway. Anticipated wall height is to not exceed 3 feet total exposed face, and will have pedestrian fall protection fencing at top, adjacent to the sidewalk for safety purposes. C. Operational concerns associated with the design element: The full design of the wall will be finalized during FAC review. D. Maintenance concerns associated with the design element: Retaining walls generally do not require a lot of maintenance. Seasonal inspection of walls is typical, but no special maintenance is required for this deviation request. The wall, wall footings drains, and landscaped slopes will be owned and maintained by the HOA for the plat. E. Liability concerns associated with the design element: Due to the location of the wall and relatively low overall height, liability concerns are considered minimal with regards to this deviation. Pedestrian fall protection fencing will be provided on top of the proposed wall to alleviate any liability concerns. The wall and associated slopes will be owned and maintained by the HOA for the plat. F. The capacity and/or efficiency of the design element: The proposed retaining wall is an efficient method of obtaining the required side slope to existing grade, without need to acquire adjacent private properties. G. The design life, historic performance, and durability of the design element: The proposed wall will be constructed to City of Auburn standards and as such will maintain the same design life, performance, and durability as other similar walls. The wall will likely be hand-placed block wall that meets City’s minimum design requirements. 585 of 628 Shannon Howard, P.E. CFM Development Review Engineer Department of Community Development City of Auburn -3- October 7, 2021 H. The aesthetic and visual impacts of the design element: The proposed wall will only be visible by the adjacent parcel to the south. The wall does not impact the aesthetics of the public street or development. Similar walls have been identified in and around the adjacent developments. I. The cost effectiveness and availability of any replacement components or materials: The proposed retaining wall will be constructed to City of Auburn standards, so there is no change in standard components or replacement materials. Costs to purchase and install block walls are generally the most cost effective in the industry. Placing the wall closer to the sidewalk would not require additional cost to the project. J. Consistency with the spirit and purpose of the corresponding City design standard: The City’s standard generally requires retaining walls to be located on private property. Exceptions are when work in the public right-of-way is restricted or limited on available area with right-of-way to provide grading necessary for new work. The roadway design has been recently shifted north in this area to provide the maximum available slope area behind the proposed sidewalk. Therefore, the spirit and purpose of the city design standard is maintained. K. Demonstration that the environment will not be adversely affected: There are no environmental impacts associated with this deviation. L. Supported by published industry standards: Retaining walls are generally allowed within this industry to be in public right-of-way, where grading and limited access issues occur, on a case-by-case basis. M. The effect on buildable lands within the City of Auburn: This deviation is only required due to the limited right-of-way access available. This deviation would only apply in similar circumstances in the City of Auburn. 586 of 628 Shannon Howard, P.E. CFM Development Review Engineer Department of Community Development City of Auburn -4- October 7, 2021 Please review this request for a retaining wall located within City of Auburn right-of-way deviation from the engineering design standards, to amend the requirement for construction of a wall within the public easement. Enclosed with this Deviation Request are engineering exhibits showing the proposed wall location. If you have any questions or need any additional information regarding this request, please feel free to contact me. Sincerely, Jason Hubbell, P.E. Senior Project Engineer JH/ca 18355c.010.doc enc: As Noted cc: Bryan Stowe, Stowe Investments LLC 10/7/21 587 of 628 NSCALE: 1"=10'588 of 628 589 of 628 October 7, 2021 Shannon Howard, P.E. CFM Development Review Engineer Department of Community Development City of Auburn 1 East Main Street Auburn, WA 98001 RE: Request for Deviation (DEV21-0036) for Wall Located in Right-of-Way, on West End of South 328th Street Carbon Trails Preliminary Plat PLT19-0002 SEP19-0003 Our Job No. 18355 Dear Shannon: We are requesting a General Deviation from the City of Auburn EDS Section 5.04 for the above- referenced project. The deviation consists of locating a retaining wall within a portion of the city-owned South 328th Street right-of-way, near the intersection with 51st Avenue South. The deviation is being requested due to right-of-way limitations that limit grading activities within the right- of-way needed to provide a public roadway connection from the 24’ wide roadway section of South 328th Street to the existing roadway at 51st Avenue South. BACKGROUND INFORMATION The proposed project is to develop three parcels in Auburn for a single-family residential plat. The three parcels are approximately 11.4 acres combined. The project is located within Section 14, Township 21 North, Range 4 East, Willamette Meridian, City of Auburn, King County, Washington. More particularly, the site is located between 51st and 56th Avenue South at South 328th Street. The site lies within a single-family zoned area. A lot of the area is still rural-type homes with large lots, but there are parcels to the south and east that have been developed into small subdivisions. One of the parcels being developed is 32727 56th Avenue South, Auburn, WA 98001. Assessor parcel numbers are 926280-0320, -0295 and -0313. The current zoning is R-5 residential. The proposal is to create approximately 44 single-family lots for development. The project would include platting, road improvements, utility extensions, storm drainage conveyance, water quality and detention to meet the City of Auburn requirements. The residential plat would meet the current R-5 zoning, including minimum lot sizes, setbacks, and impervious surface coverage. The proposed single-family homes would likely be in the 2,500-3,500-square-foot range with fenced yards and appropriate landscaping and street trees. This site has limited access to public right-of-way at 51st Avenue South, limited to a narrow opening in the northwest corner of the site. The justification for requesting the retaining wall in the right-of-way is as follows per City Engineering Design Standards 1.04.1: 590 of 628 Shannon Howard, P.E. CFM Development Review Engineer Department of Community Development City of Auburn -2- October 7, 2021 JUSTIFICATION A. The functional intent of the design element: The retaining wall is proposed within the right-of-way due to limited right-of-way to perform grading necessary for new street connection of South 328th Street to 51st Avenue South, while maintaining function of two existing driveways to the private property to the north. The project developer has been in contact with the private property owner, who is unwilling to dedicate or allow property to be purchased to allow additional slope grading on his property. B. Safety factors associated with the design element: The wall has been located to minimize wall height and is set back from the roadway to the maximum extent possible to avoid sight lines nearing the intersection with 51st Avenue South. Protective fencing will be provided on top of the proposed wall, as required for fall protection. C. Operational concerns associated with the design element: There are minimal operational concerns associated with retaining walls. D. Maintenance concerns associated with the design element: Retaining walls generally do not require a lot of maintenance. Seasonal inspection of walls is typical, but no special maintenance is required for this deviation request. Due to the high visibility location of the proposed wall, the wall will be constructed with Anti-Graffiti treatments to reduce maintenance concerns. The wall, wall footings drains, and landscaped slopes will be owned and maintained by the HOA for the plat. E. Liability concerns associated with the design element: Due to the location of the wall, liability concerns are considered minimal with regards to this deviation. Pedestrian fall protection fencing will be provided on top of the proposed wall to alleviate any liability concerns. The wall and associated slopes will be owned and maintained by the HOA for the plat. F. The capacity and/or efficiency of the design element: The proposed retaining wall is an efficient method of obtaining the required roadway constructable area for improvements, without need to acquire adjacent private properties, which has proven futile to-date. G. The design life, historic performance, and durability of the design element: The proposed wall will be constructed to City of Auburn standards and as such will maintain the same design life, performance, and durability as other similar walls. The proposed wall is considered “somewhat” temporary, in that future development of the property to the north, as 591 of 628 Shannon Howard, P.E. CFM Development Review Engineer Department of Community Development City of Auburn -3- October 7, 2021 well as future build-out of the west end of South 328th Street/51st Avenue intersection, would likely result in the removal of the wall (or relocated to private property). H. The aesthetic and visual impacts of the design element: The wall does not impact the aesthetics of the public street or development. Similar walls have been identified in and around the adjacent developments. I. The cost effectiveness and availability of any replacement components or materials: The proposed retaining wall will be constructed to City of Auburn standards, so there is no change in standard components or replacement materials. J. Consistency with the spirit and purpose of the corresponding City design standard: The City’s standard generally requires retaining walls to be located on private property. Exceptions are when work in the public right-of-way is restricted or limited on available area with right-of-way to provide grading necessary for new work. The area of the proposed retaining wall is in an area where public right-of-way becomes reduced from 60-feet-wide down to 30-feet-wide, and the adjacent owner is unwilling to allow improvements to impact their property. Therefore, the spirit and purpose of the city design standard is maintained. K. Demonstration that the environment will not be adversely affected: There are no environmental impacts associated with this deviation. L. Supported by published industry standards: Retaining walls are generally allowed within this industry to be in public right-of-way, where grading and limited access issues occur, on a case-by-case basis. M. The effect on buildable lands within the City of Auburn: This deviation is required due to the limited right-of-way access available. This deviation would only apply in similar circumstances in the City of Auburn. The wall will be designed to accommodate future buildout of the roadway, and full design of the wall will be finalized during FAC review. 592 of 628 Shannon Howard, P.E. CFM Development Review Engineer Department of Community Development City of Auburn -4- October 7, 2021 Please review this request for a retaining wall located within City of Auburn right-of-way deviation from the engineering design standards, to amend the requirement for construction of a wall within the public easement. Enclosed with this Deviation Request are engineering exhibits showing the proposed wall location. If you have any questions or need any additional information regarding this request, please feel free to contact me. Sincerely, Jason Hubbell, P.E. Senior Project Engineer JH/ca [18355c.009.doc] enc: As Noted cc: Bryan Stowe, Stowe Investments LLC 10/7/21 593 of 628 NSCALE: 1"=10'594 of 628 595 of 628 596 of 628 597 of 628 598 of 628 599 of 628 600 of 628 601 of 628 602 of 628 603 of 628 604 of 628 © First American Title 0.1 Miles0.1 Notes Maps are intended for informational purposes only. Some information has been procured from third-party sources and has not been independently verified. Independent parts are owned by their respective copyright owners and not by First American. First American Title Company makes no express or implied warranty respecting the information presented and assumes no responsibility for errors or omissions. 0.070 3131861 12/7/2018 605 of 628 606 of 628 607 of 628 608 of 628 609 of 628 610 of 628 611 of 628 612 of 628 613 of 628 1 18355.004.docx Neighborhood Meeting Notes - Carbon Trails Plat Evergreen Heights Elementary January 9, 2019 - 6 p.m. Meeting Notes by Karen Harris, Project Engineer, Barghausen Consulting Engineers, Inc.: Approximately 45-50 people were in attendance. We included a large format print of the plat and an aerial mark-up of the proposed sanitary sewer extension. A short introduction was given by Jason Hubbell, Senior Project Engineer of Barghausen Consulting Engineers, Inc. · Introduced Bryan Stowe, Stowe Investments LLC, the owner/developer, and Karen Harris, Project Engineer, Barghausen Consulting Engineers, Inc. · Discussed plat layout and street improvements · Discussed sanitary sewer extension, all within public property to alleviate private property impacts · Explained other utilities would be extended as well (water, gas, electricity, telephone, etc.) · Touched on the fact that 51st Street has some issues with grades, being out of the right-of-way · Opened the floor to questions Questions/Responses: These comments and responses are not verbatim and have been summarized from notes taken during the meeting. · Is the City of Auburn in attendance? It was explained that the City does not attend the neighborhood meeting. This is a very preliminary step and the project has not been submitted to the City to obtain SEPA or permits yet. Jason explained the SEPA and permitting process and said there would be a chance to discuss the project with the City during the SEPA review and the Hearing Examiner’s Meeting. · Who is on the mailing list? Jason explained the 300-foot radius and the mailing list. The people on the mailing list for the neighborhood meeting would be on the SEPA mailing list as well. Neighbors indicated that the signs were not in a location to be seen by enough people - people that would be impacted by the project. It was noted that one of the meeting signs had blown over in the wind storm. 614 of 628 2 18355.004.docx · How long until construction? Approximately 12-15 months until construction starts. Approximately 6 months of grading, utilities and street construction. Home construction will begin approximately 2 years from now and will likely be done in 1 year. · Who pays for the sewer? Jason discussed how the sewer would be paid for by the developer but there would be a latecomer’s agreement that would require adjacent property owners to pay a pro-rated share of the sewer construction cost if they wanted to connect/utilize the public sewer. Jason noted that this was in the Lakehaven Water and Sewer District and so was not as familiar with the latecomer’s agreement process and how much it would cost. There was a discussion about connection costs vs. the latecomer’s costs in terms of scale/dollar amount. One neighbor said the City makes you pay the latecomer’s when you are selling/buying a property, or if your septic fails. Jason communicated that it was typically triggered when you request a building permit from the City (new construction, addition, etc). A concern was also expressed about the capacity of the treatment plant. Jason discussed the sewer availability that was obtained from Lakehaven who required the sewer extension but did not express limits on sewage flow or capacity issues. · What improvements will there be along our frontage? There was a general discussion about the size of the proposed road (width) and sidewalks on both sides. And no proposed improvements to 51st or 56th. The road width is proposed to be 28 feet from face of curb to face of curb. · Will there be a new traffic signal? No. Jason noted that a traffic study had been done and a traffic signal was not warranted. A 4-way stop was discussed at South 328th and 56th, but it was explained that a 4-way stop is not usually introduced when one road is a larger capacity such as 56th. Neighbors are very concerned about the current traffic issues and how 44 new lots would impact what they feel is already a difficult traffic situation. Neighbors stated that some streets have issues with excessive speeds by drivers. · How large will the lots be? How large will the homes be and what price? The lots will be approximately 6,000 square feet on average with 2,500 to 3,500-square-foot 2-story homes. Since the builder is not known, the future home prices are also unknown. · How is storm drainage being dealt with? Jason explained how we would be collecting runoff from the roofs, streets and yards and directing it to the pond with catch basins and pipes. The pond will control the runoff to pre-developed 615 of 628 3 18355.004.docx rates. The pond will have standing water for water quality and then during a rainfall event the pond would fill up and release water slowly through a control structure. Runoff would be to the south and a small portion would be directed to the storm system in 51st. The resident just south of the pond identified themselves and Jason asked to discuss the pond and drainage with them after the meeting. That meeting occurred and the homeowner expressed that they have drainage issues on their property already. The homeowner was in general acceptance with the proposed storm design and no concerns were made with the proposal. One homeowner to the west voiced issues with springs/groundwater on 46th. It was discovered that the homeowner was not along the downstream path from this development so would not be affected by the development. Jason suggested that the homeowner file a formal drainage complaint to try and get assistance from the City of Auburn with his issue. There was a comment about the proposed pond causing an issue with mosquitoes. Some neighbors said the forest as it currently is has lots of mosquitoes already. There was a question about the existing wetland, including the buffer size and class and if there was a report. It was noted there was a 50-foot buffer and we thought it was a Class 3 wetland but we could not recall for sure. Jason explained that after the SEPA submittal the wetland report could be requested through a public records request. The homeowner was familiar with that process. Jason and I discussed how the wetland is at the top of the hill and appears to overflow both to the north and south. We explained that we wanted to keep the wetland as it currently functions, ponding water and then overflowing. Jason discussed that we were providing a storm pipe to route the wetland overflow to the south to its natural downstream. · Why is 51st Street not being improved? It is a safety hazard since fire trucks won’t be able to make it into this development. Construction traffic cannot be handled on 51st. The difficulties with 51st Street being improved were further discussed. It was noted that the project is proposing to fully improve South 328th Street instead of making improvements to 51st. It was noted that the existing road is outside of the public right-of-way. The steep grades were discussed, including the maximum road grades allowed by the City of Auburn and for fire truck access. The existing roadway is on private property and the City does not have a full 60-foot right- of-way width along 51st. Obtaining the right-of-way was discussed. One idea was to extend South 328th west to 46th since it will be torn up for the sanitary sewer extension already. Neighbors noted this would provide traffic relief. There is currently only a 30-foot right-of-way so a road extension could not be built and is outside the parameters of this project. A one-way road was suggested. The plans will not include 51st as a haul route or construction entrance. Construction traffic will likely use the existing driveways off of 56th north of 328th. 616 of 628 4 18355.004.docx · Who at the City can we contact about the issues we have? Dustin Lawrence, City of Auburn Planner Steve Sturza, City of Auburn Engineer · Will gas be extended through the site? Yes. · Will there be an HOA? Yes, but it will only include these 44 lot owners. No impacts to existing landowners. · Will electricity be underground? Yes. It will be routed from a nearby pole and routed below ground along South 328th. Neighbors noted that during power outages they are slow to get power back and this neighborhood would be on that same power system. · It was noted that there are some utilities in the existing right-of-way, specifically a water meter, and what would be done with the utilities during construction? It was assured that existing utilities may need to be relocated during construction, but efforts would be made to limit the impact to residents and the utilities would be restored and not eliminated. · One neighbor noted that he has had issues dealing with the City of Auburn and the Canyon Creek development. He expressed concern that the City doesn’t care about the neighbors, they are only concerned with increased property taxes. The developer/engineer/City will do the minimum amount to make money. The City is not acting as a mediator between development and neighbors. The neighbors need to work together to prevent safety issues, construction defects, etc. The neighbors need to work together to make sure the City knows the issues on traffic, school impacts. He was concerned the City would use retribution tactics if the neighbors complained, like the slow speed on West Valley Highway was a result of a bond not passing. · Will there be a fence around the pond? Yes, there will be a 48-inch fence around the pond as required by the City of Auburn. The only fences around the property will typically be a 6-foot cedar fence around the back of lots provided by the home builder. 617 of 628 5 18355.004.docx · A neighbor expressed concern about shaking during construction. He advised neighbors to take pictures of their homes to document any impacts from vibrations and construction machinery. He noted that he has had home damage from the project to the northwest, including cracks in his sheetrock. · How will we be impacted by construction with the street excavated/under construction? Jason discussed that temporary access will be provided during construction and homeowners will not be prevented from getting to their property. · A neighbor expressed concern about construction standards and poor quality construction, including a tall wall adjacent to his property that was constructed without a foundation. Neighbors need to be diligent to keep the contractor from creating safety issues. The neighbors asked how they would get updates on the project. Bryan Peterson volunteered to act as a neighborhood contact so Jason could send information to him and he could distribute to the group. The question and answer session ended at about 7 p.m. and Jason asked some of the adjacent homeowners if they could stay, if available, to discuss specific issues. Some of those discussions are summarized above under the question/answer session notes as it corresponded to the question. I discussed the grading along the northeast corner of the site with the property owner to the north. He was concerned about the new project blocking drainage and impacting existing trees. I showed him the plans that include a ditch along the back of those lots that direct runoff to the wetland and explained how the wetland/wetland overflow works. I also noted some large trees just off the property that will need to be looked into further to make sure the proposed grading isn’t impacting those trees. The property owners on the northwest side of the project looked at the proposed impacts to their properties. One homeowner discussed the impacts to their driveway landscape island and their existing tree and how the proposed roadway would demolish the landscape island. They also have some large cedar trees that may be impacted by the roadway construction. The roadway grades are being designed to try and closely match the existing grades in this area to limit the impacts to the existing trees. The grading issues were discussed with the western property owner (Bryan Peterson) and how the existing grades were making it very difficult to match into that property with the road grade restrictions required by the City of Auburn. He also had trees on his property that he was concerned would be impacted by the road construction. Jason asked that they have an on-site meeting to discuss the grading issues as the project progresses. The road section was discussed, proposed improvements vs. minimum requirements to show the impact difference between the two. The meeting concluded at 8 p.m. 618 of 628 619 of 628 620 of 628 621 of 628 622 of 628 623 of 628 624 of 628 625 of 628 626 of 628 627 of 628 628 of 628