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10-16-2019 HE Packet Knudson 10.16.19
HEARING EXAMINER October 16, 2019 5:30 p.m. City Council Chambers 25 West Main Street I. Case No: PLT18-0006, Knudson Preliminary Plat Applicant(s): Jamie Waltier Project Manager Harbour Homes, LLC 400 N. 34th St Seattle, WA 98103 Property Owner: Gerald Knudson 30106 124th Ave SE Auburn, WA 98092 Request: Preliminary plat application to subdivide approximately 3.31 acres into 17 single-family residential lots. Project Location: The project site borders the east side of 124th Ave. SE, approximately 130 feet north of SE 302nd P. and west of the end of SE 301st Pl., within SE ¼ of Section 4, Township 21, Range 5 Parcel Number(s): 0421059034. 1 of 189 AGENDA BILL APPROVAL FORM HEARING EXAMINER Agenda Subject/Title: PLT18-0006, Knudson Preliminary Plat Date: September 30, 2019 Department: Community Development Budget Impact: Current Budget: $0 Proposed Revision: $0 Revised Budget: $0 DESCRIPTION: Preliminary plat application to subdivide approximately 3.31 acres into 17 single-family residential lots in the R-5, Residential Zoning District. ADMINISTRATIVE RECOMMENDATION: Hearing Examiner to conduct a public hearing and approve the preliminary plat of Knudson with 15 conditions and the associated the Plat Modification Request, and the Engineering Deviation request. PROJECT SUMMARY: Preliminary plat application to subdivide approximately 3.31 acres into 17 single-family residential lots. The site is zoned R-5, Residential, which allows 4-5 dwelling units per acre. The proposed lots range in size from 4,668 square feet (SF) to 7,687 SF. Roadways to be constructed include the public extension of SE 301st Pl. (from The Ridge at Willow Park Subdivision) to form a cul-de-sac, three (3) new private access tracts stemming off of SE 301st Pl. SE, and one (1) emergency/pedestrian access tract connecting to 124th Ave. SE. Stormwater will be managed on-site via a stormwater pond (Tract E). Water and sewer will be extended through the site to service each lot. LOCATION: The project site borders the east side of 124th Ave. SE, approximately 130 feet north of SE 302nd P. and west of the end of SE 301st Pl., within SE ¼ of Section 4, Township 21, Range 5. King County Assessor Parcel No. 0421059034. APPLICANT(S): Jamie Waltier, Project Manager, Harbour Homes, LLC, 400 N 34th St., Seattle, WA 98103 APPLICANT’S REPRESENTATIVE: Maher Joudi, Principal, General Manager, D.R. Strong Consulting Engineers, Inc., 620 7th Ave., Kirkland, WA 98033 PROPERTY OWNER(S): Gerald Knudson, 30106 124th Ave. SE, Auburn, WA 98092 2 of 189 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 Single-family Residence and associated accessory structures North Single Family R-5 Residential Zone Single-Family Residences / Recreation Tract South Single Family R-5 Residential Zone Single-Family Residences East Single Family R-5 Residential Zone Single-Family Residences West Urban Separator (City of Kent designation within an incorporated island) Single Family SR-1 (City of Kent designation) Vacant portion of The Bridges Planned Unit Development (PUD) (within City of Kent) Excerpted Zoning Map: 3 of 189 Excerpted Comprehensive Plan Map: 2017 Aerial Vicinity Map: 4 of 189 Street Layout Map: SEPA STATUS: A Determination of Non-Significance (DNS) was issued under City File No. SEP19-0012 on August 28, 2019, see Exhibit 4. The comment period ended September 12, 2019 and the appeal period ended September 26, 2019. 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. Jamie Waltier, Project Manager, with Harbour Homes, LLC, on behalf of Gerald Knudson, Property Owner, submitted a Preliminary Plat application and associated SEPA application 5 of 189 on November 15, 2018 to subdivide approximately 3.31 acres (referred to in this Staff Report as the “Site”) into 17 single-family residential lots, three new private access tracts stemming off of SE 301st Pl. SE (Tracts A, B, and C), one emergency/pedestrian access tract connecting 124th Ave. SE (Tract D), and one stormwater pond tract (Tract E), referred to in this Staff Report as the “Project”. 2. The Site consists of one parcel and is located in the Lea Hill portion of the City, between 124th Ave. SE to the west and SE 301st Pl. to the east, and approximately at the west end of S. 302nd Pl., south end of 57th Pl. S, and approximately 580 ft. north of the intersection of 124th Ave. SE and SE 304th St. The Site is located within the City of Auburn’s corporate limits, and referenced by King County Tax Assessor Parcel No. 0421059034. 3. The Site has a Comprehensive Plan designation of “Single Family Residential” and 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 3.13 acres, which in accordance with the density calculation would require between 13 and 16.55 (rounded to 17 per Auburn City Code (ACC) 18.02.065(A)(1)(a)) lots. 4. The Project is subject to the zoning development standards for the R-5 zoning district in effect at the time the Project application was considered “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 o Side, interior: 5 feet o Side, street: 10 feet o Rear: 20 feet 5. Per ACC 18.52.020 two off-street parking spaces per single family residence is required. 6. The Site currently has one single-family home and a three accessory structures (barn, garage, and a shed). The home and associated accessory structures will be demolished. The site is also currently served by an existing on-site septic system and well; the existing septic system and well will be field located and abandoned prior to commencement of grading activities. Per ACC 13.06.150(C)(D) the applicant will also be required to sign an service agreement transferring water rights (if appropriate) and prohibiting the future installation of an irrigation well. 7. The Site is rectangular in shape, as shown and dimensioned here: 6 of 189 8. The Site is bordered by an existing “Local Residential” classified street to the east (SE 301st Pl.), and an “Minor Arterial” classified street (124th Ave. SE) to the west. SE 301st Pl. will be extended through the Project with full street improvements meeting “local residential” standards, and terminate in a cul-de-sac. Three new private access tracts (Tracts A, B, and C) will stem off of SE 301st Pl. SE. One emergency/pedestrian access tract will connect to 124th Ave. SE. For full size plans, see Exhibit 6. 9. The Site is located within the utility service areas of, and will be served by, City of Auburn for public water and sewer. City public water and sewer service will be extended from SE 301st Pl. through the Site connecting to 124th Ave. SE. 10. The Site is slopes gradually from east to west, with most of the sloping occurring on the western edge of the property. The northwest corner of the property is noted as “erosion prone” under the City’s critical area inventory mapping system. The Applicant has provided the City with adequate information to show that the project will be in conformance with the City’s Critical Areas Code and Engineering Design Standards. Reference the Geotechnical Report (Exhibit 8). 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). As recommended in the Preliminary Stormwater Site Plan (Exhibit 9), stormwater runoff from the Project will be evaluated, treated, and detained in a stormwater detention facility (‘stormwater pond’) located in Tract E, per the Department of Ecology Stormwater Management Manual for Western Washington (SWMM) and Auburn Supplements. 12. The Site is not located within any shoreline designation. 492 ft. 462 ft. 319 ft. 302 ft. 7 of 189 13. The Site is not located in the regulatory floodplain per Federal Emergency Management Agency (FEMA) maps. 14. There are no wetlands, streams, priority habitat areas, or state or federal candidate threatened or endangered plant or animal species identified on the Site (reference the Wetland, Fish, and Wildlife Habitat Assessment, Exhibit 7). 15. 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), a portion of the site is located in a “High Risk” area for archaeological resources and denotes that a cultural resources survey is “highly advised”. Therefore, the project is conditioned such that prior approval of the construction plans under the Facilities Extension Agreement (FAC), the Applicant must prepare a cultural resources investigation report meeting the guidelines of the Washington Department of Archaeology and Historic Preservation (DAHP) and provide it to the City of Auburn Community Development Dept., Muckleshoot Indian Tribe, and DAHP for review. 16. There are occupation features (apparent property line encroachments) along the northeast boundary of the Site (i.e. fences, retaining wall, and rockery) affecting the boundary between the subject site and adjoining parcels, which are shown and appropriately dimensioned. Any potential adverse claims and/or unwritten rights associated with the depicted occupation features is a civil matter between private parties. During the civil plan review process, any encroaching fence, retaining wall, and rockery will need to be relocated or an easement granted to the retaining wall owner. The City’s review of this preliminary plat application is for its conformity to Auburn City Code and state platting law, and as such does not address nor adjudicate any potential unwritten rights that may be acquired by the Applicant or the adjoiners. the project is conditioned such that a note will be required on the Final Plat if these remain unchanged and/or unresolved at the time of final plat application. 17. SE 301st Pl. currently provides access for 18 lots in The Ridge at Willow Park Subdivision. This road is proposed to be extended to provide access for the 17 lots of the subject Project, the result will exceed city standards for the number of lots permissible to be served by one road without an additional emergency vehicle access. Therefore, the project is conditioned such that prior to issuance of building permits the emergency vehicle access tracts (Tract C and D) must be completed and open to the public street (124th Ave. SE). 18. Half-street improvements will be required to 124th Ave. SE including the dedication of approximately 3.70’ of right-of-way, curb, gutter, sidewalks, street lighting, stormwater controls, and landscape strips to meet the City’s “Minor Arterial” standard. 19. To enhance the pedestrian experience from the public sidewalk along 124th Ave. SE, the portion of the stormwater pond tract (Tract E) located between the westernmost retaining wall and the back of the right-of-way of 124th St. SE will be landscaped with shallow-rooted shrubs and groundcover. 20. To mitigate temporary noise impacts associated with the Project, all construction shall occur between the hours of 7 AM and 7 PM on weekdays, and between 9 AM and 6 PM on Saturday and Sunday as required per ACC 8.28.010(B)(8). 8 of 189 21. 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’. 22. 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’. 23. 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’. 24. 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’. 25. A combined Notice of Application, Notice of Public Hearing, and Determination of Non- Significance (DNS), was issued on August 28, 2019 (Exhibit 4). The notices were posted at the Site, mailed to property owners within 300 ft. of the Site, and published in The Seattle Times newspaper. 26. In response to the public notice the City received one comment letters from one individual as of September 30, 2019 (the date this Staff Report was finalized) on the project. The following list is Staff’s abbreviated summary of the comment(s) along with a short summary of the City’s response, if one was necessitated. The comment and response is included as Exhibit 5. a. Larry Fisher (Area Habitat Biologist, Washington Department of Fish and Wildlife (WDFW)): commented that the checklist lacked adequate detail in the stormwater runoff section to determine where stormwater will be discharged. He indicated that if the project requires a new outfall to state waters, a Hydraulic Project Approval will be required from WDFW. City Response: Staff’s response included that the stormwater will be collected and discharged to a stormwater draining facility located in the northwestern portion of the proposed plat. Also the public land use notice page for the proposed plat contains a link to the preliminary plat civil drawings and preliminary stormwater site plan. Subsequently, Mr. Fisher was able to located the discharge points and expressed no further concerns about the proposal. Plat Modification Findings 1. In accordance with the subdivision code section ACC 17.14.090(D), ‘Lot Requirements’ corner lots must be platted five feet wider than required by the zoning ordinance. The minimum lot width for an internal lot in the R-5 zone is 50 feet. Therefore, all corners lots must be platted a minimum of 55 feet in width. 9 of 189 2. On August 13, 2019, the Applicant requested a plat modification for relief from the minimum lot width applicable to corner lots (Exhibit 11). Lots numbered 2, 5, 7, and 13 do not meet the minimum lot width requirement for corner lots. These four lots, however, are proposed to meet the street side setback of ten feet as routinely required for corner lots. 3. Per ACC 17.18 ‘Modifications for Formal Subdivisions’, the Hearing Examiner may approve a modification of any standard or specification established or referenced by Chapter 17.14 ACC ‘Improvement Requirements – Subdivisions’. See ‘Plat Modifications Conclusions’, below. While the Applicant refers to the request for relief from the corner lot width standard as a “variance”, since the standard originates from the subdivision code, it is more appropriately a “modification of subdivision standard”. Engineering Deviation Findings 1. On November 16, 2018 the applicant submitted request for a “deviation” from the City of Auburn Engineering and Design Standards (COADS) to increase the maximum road grade of SE 301st Pl. and the emergency vehicle and pedestrian access tract (Tract D) from 8% to 10% (City File No. DEV19-0025, Exhibit 12). 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 request and conditionally recommends approval (Exhibit 12), see Condition No. 2 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: 10 of 189 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 is not subject to any park dedication, open space, or clustering requirements under Title 18 ‘Zoning’ or Title 17 ‘Land Adjustments and Divisions’. Drainage Ways: No existing drainage ways appear to be located on the Site. 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 E, per the Department of Ecology Stormwater Management Manual for Western Washington (SWMM) and Auburn Supplements. 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 extension of SE 301st Pl. and the half-street improvements to 124th Ave. SE, the City’s Transportation Division finds that there will be no decrease in the road network level of service (LOS) standard. Additionally, as provided in ‘Finding of Fact’ No. 24, each new residence will be required to pay the Traffic Impact Fee in place at time of 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 124th Ave SE. 2. SE 301st Pl. will be extended, east-west, from The Ridge at Willow Park Subdivision westerly into the Site. The extended road will terminate in a cul-de-sac. 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. Parking will be allowed on the northern side of the road. Twelve lots (Lots No. 1, 2, 5-7, 13-17) will take access from this road. 3. Tract A is a private access tract (joint use driveway) featuring a paved width of 20 feet (tract is 25 ft. in width). Two lots (Lots No. 3 and 4) will take access from this private access tract. The tract will be marked “No Parking” on both sides. Tract A will be owned and maintained by the HOA. 4. Tract B is a private access tract (joint use driveway) featuring a paved width of 20 feet (tract is 25 ft. in width). Two lots (Lots No. 8 and 9) will take access from this private access tract. The tract will be marked “No Parking” on both sides. Tract B will be owned and maintained by the HOA. 5. Tract C is a private access (joint use driveway), and partly an emergency vehicle access, and pedestrian access tract featuring a paved width of 20 feet and a five foot 11 of 189 sidewalk on one side (tract is approx. 29.5 feet in width). One lot (Lot No. 12) will take access from Tract C. Tract C will be owned and maintained by the HOA. An ingress and egress easement, or other instrument as approved by the City, over Tract C must be granted to the City of Auburn, for the purpose of accessing Tract E (stormwater pond), providing emergency services, and pedestrian access to 124th Ave. SE. 6. Tract D is a continuation of the emergency vehicle and pedestrian access tract in Tract C. Tract D features a paved width of 20 feet (tract will vary in from 25 ft. to approx. 29.5 ft. in width). The tract will be striped “No Parking – Fire Lane”. A gate with a ‘knox box’ padlock will prohibit non-emergency vehicular access from 124th Ave. SE. A separate pedestrian path will be required to provide access that is outside of the driving surface and not impeded by the gates; this connection is required to provided ADA-compliant access. Tract D will be owned and maintained by the HOA. An ingress and egress easement, or other instrument as approved by the City, over Tract D must be granted to the City of Auburn, for the purpose of accessing Tract E (stormwater pond), providing emergency services, and pedestrian access to 124th Ave. SE. 7. Pedestrian access will be provided through the plat from SE 301st Pl., through Tract C and Tract D, to 124th Ave. SE. Access to the stormwater pond (Tract E) will also be provided from 124th Ave. SE through Tract D. Based on the City’s Comprehensive Transportation Plan, Functional Roadway Classification Map, the extension of SE 301st Pl. will be a “Local Residential” street. One Deviation has been requested to increase the maximum road grade of SE 301st Pl. and the emergency vehicle and pedestrian access tract (Tract D) from 8% to 10%, of, which the City Engineer has conditionally recommended for approval; reference the “Engineering Deviation Conclusions” below. Public Water: The Site is located in the City’s water service area. Adequate water service will be provided for the Project. Water will be extended from the existing water main in SE 301st Pl. west through the plat (via SE 301st Pl., Tract C, and Tract D) to the existing water main in 124th Ave. SE. Public Sanitary Sewer: The Site is located in the City’s sewer service area. Adequate sanitary sewer service will be provided for the Project. Sanitary sewer service will be extended through the plat from SE 301st Pl. (through Tract C and D) to connect into the existing sewer main in 124th Ave. SE. Parks, Playgrounds: No parks or playgrounds are proposed for the Project and none are required under city code authority. Per ‘Finding of Fact’ No. 21, Park Impact Fees will be paid at the time of building permit issuance (currently $3,500.00 per unit). The closest park is “Auburndale 2” (located north of the intersection of 118th Ave. SE and SE 304th St.). Auburndale 2 is approximately 9.34 acres in size, features a walking trail, and is 0.91 miles away from the Site (reference image below). While not yet a park, the Jacobsen Tree Farm, is 29.04 acres in size and is approximately 1.2 miles (via SE 304th St) from the Site. The tree farm site was transferred from King County to the City in 2003, and per the City of Auburn Parks, Recreation, and Open Space (PROS) Plan, it will be converted and 12 of 189 developed into a multi-use sports facility. The park is still in planning stages as the Parks Dept. must secure funds for its development. Schools: The Site is located within the Auburn School District (ASD) boundary. Per the Applicant, students within the Project will attend: 1) Arthur Jacobson Elementary School; 2) Rainier Middle School, and 3) Auburn Mountainview High School. Students will be bussed from a bus stop located near the intersection of 124th Ave. SE and SE 302nd Pl. to their respective schools. Students will travel through the Site, to 124th Ave. SE, via Tract C and Tract D, where they will walk to SE 302nd Pl. A safe walking route to the bus stop will be provided via the installation of sidewalk along the frontage of the Project as part of required half-street improvements, and existing sidewalk that was constructed with the plat directly to the south of the Site (Alicia Glen plat, reference image below). This information was obtained from the “E-Link School/Transportation Information Portal” for the ASD. 13 of 189 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 3.31 acres into 17 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. City of Auburn public 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 northwestern portion of the Site (Tract E).The stormwater pond will be required to meet applicable code and engineering design standards, as conditioned below. SE 301st Pl., a “Local Residential” public street will be extended to serve the proposed Project. Sidewalks will be constructed on both sides of the extended road. The Project will connect pedestrians to 124th Ave. SE via Tract C and Tract D, both of which are intended to provide pedestrian access. Pedestrian access will be enhanced along 124th Ave. SE by the dedication of approx. 3.70’ of right-of-way and construction of half-street improvements, which will include sidewalks. Public services such as the Auburn Police Department, Valley 14 of 189 Regional Fire Authority, and the Auburn School District will also serve the proposed Project. The Project will use an existing bus stop, located south of the proposed Project, near the intersection of 124th Ave. SE and SE 302nd Pl. Finally, impact fees including 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.” 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.” “Objective 1.2. To ensure that new developments are supported by an adequate level of public services through an effective system of public facilities.” 15 of 189 Policies: “CF-10 Public facilities shall be provided in accord with the guidance of the Capital Facilities Plan or, as may be appropriate a system plan for each type of facility designed to serve at an adequate level of service the locations and intensities of uses specified in this comprehensive plan.” “CF-12 No new development shall be approved which is not supported by a minimum of facilities to support the development and which does not provide for a proportionate share of related system needs.” “Objective 1.3. To ensure safe and adequate water service, for both domestic and fire protection purposes, to meet the needs of the existing community and provide for its planned growth.” “CF-16 The City shall continue its policy of requiring that water system extensions needed to serve new development shall be built prior to or simultaneously with such development, according to the size and configuration identified by the Comprehensive Water Plan as necessary to serve future planned development. The location and design of these facilities shall give full consideration to the ease of operation and maintenance of these facilities by the City. The City shall continue to participate to the extent permitted by law, through direct participation, LIDs, and payback agreements, to assist in the financing of such oversized improvements. Wherever any form of City finance is involved in a waterline extension, lines that promote a compact development pattern will be favored over lines traversing large undeveloped areas with uncertain future development plans.” “Objective 1.4. To ensure the efficient transmission of sanitary sewage to the appropriate treatment and disposal facilities in order to meet the needs of the existing community and provide for its planned growth.” “CF-23 The City shall continue its policy of requiring that sewer system extensions needed to serve new development shall be built prior to or simultaneously with such development, according to the size and configuration identified by the Comprehensive Sewer Plan and Comprehensive Plan as necessary to serve future planned development. The location and design of these facilities shall give full consideration to the ease of operation and maintenance of these facilities by the City. The City shall continue to use, to the extent permitted by law, direct participation, LIDs and payback agreements to assist in the financing of such oversized improvements. Wherever any form of City finance is involved in a sewer line extension, lines that promote a compact development pattern will be favored over lines traversing large undeveloped areas where future development plans are uncertain.” “Objective 1.6. To ensure that collection, conveyance, storage and discharge of storm drainage is provided in a sufficient and environmentally responsible manner, in order to meet the needs of the existing community and provide for its planned growth.” Policies: 16 of 189 “CF-37 The City shall require developers to construct storm drainage improvements directly serving the development, including any necessary off-site improvements.” 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.” “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. 17 of 189 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 Knudson Preliminary Plat is a 17-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. 3, the R-5 zoning district has a density range of between 4 and 5 dwelling units per acre. As the site is approximately 3.13 acres, which based on the density calculation requires between 13 and 16.55 (rounded to 17 per ACC 18.02.065(A)(1)(a)) lots. As proposed, the Project will contain 17 lots, the base density for the R-5 zoning district. Therefore, the Project will not create an overcrowding of the land. B. Promote safe and convenient travel by the public on streets and highways; Staff Analysis: The Project is extending SE 301st Pl. and constructing new pedestrian access tracts to and through the Project 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. 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; 18 of 189 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 east to west, with slopes ranging from approximately 2% to 30% (the majority of the sloping occurs within the western portion of the Site). As typical of site development for a preliminary plat without critical areas (e.g. wetlands and steep slopes), the Site will be cleared of vegetation and graded in preparation of the placement of site improvements such as the extension of SE 301st Pl., creation of a stormwater detention facility, home sites, and the installation of utilities. Per the Geotechnical Report (Exhibit 8), generally, the in-situ soils will not be suitable for use as structural fill due to higher soil moisture content; therefore, structural fill and soil will be imported to the Site. Further, to reduce stormwater discharges, areas of the Site will be revegetated. As proposed in the Preliminary Civil Plans (Exhibit 6), landscape strips along SE 301st Pl. will contain sod lawn and street trees. The area inside the stormwater pond tract (Tract E) will be hydroseeded. Also, as conditioned below, the area between the westernmost retaining wall at the stormwater pond and the back of right-of-way of 124th Ave. SE will be landscaped with shallow-rooted shrubs and groundcover. 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, and a pedestrian connection to 124th Ave. SE. 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 17 new single-family residences to serve future residents. J. Require uniform monumenting of land divisions and conveyance by accurate legal description; 19 of 189 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 requested plat modification (corner lot standard) and engineering deviation (maximum grade), which are discussed under ‘Plat Modification Conclusions Related to Lot Width’ and ‘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 (reference ‘Finding of Fact’ No. 4). 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 Wetland, Fish, and Wildlife Habitat Assessment (Exhibit 7), there are no wetlands, streams, priority habitat areas, or state or federal candidate threatened or endangered plant or animal species identified on the Site. The northwest corner of the property is identified in the City’s critical areas inventory as “erosion prone”. However, the proposed modification of ground and soils has been analyzed and addressed in the Geotechnical Report (Exhibit 8), and the Site has been deemed suitable for development and with meeting city standards, erosion can be minimized or avoided. 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 DNS was issued on August 28, 2019 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. 20 of 189 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 Department of Ecology Stormwater Management Manual for Western Washington (SWMM) and Auburn Supplements. Staff therefore finds the Project meets this criterion, as conditioned herein. Plat Modification Conclusions Related to Lot Width for corner lots Per ACC 17.18 ‘Modifications for Formal Subdivisions’, the Hearing Examiner may approve a modification of any standard or specification established or referenced by Chapter 17.14 ACC ‘Improvement Requirements – Subdivisions’. Per ACC 17.14.090(D), ‘Lot Requirements’ corner lots must be platted five feet wider than required by the zoning ordinance. As proposed, one side of Lots No. 2, 5, 7, and 13 abut an access tract and therefore as a corner lot must be platted five feet wider. The minimum lot width for the R-5 zoning district is 50 feet, which given ACC 17.14.090(D), each corner lot must be 55 feet in width. The applicant has requested a plat modification for each of the aforementioned lots to be 50 feet in width. ACC 17.18.030 lists the findings that the Hearing Examiner must make for approval of a plat modification; the criteria are as follows (in italics) followed by Staff analysis: A. Such modification is necessary because of special circumstances related to the size, shape, topography, location or surroundings of the subject property, to provide the owner with development rights and privileges permitted to other properties in the vicinity and in the zoning district in which the subject property is located; 21 of 189 Staff Analysis: Approving this plat modification request would provide the Applicant with similar privileges as other properties in the surrounding area. Lots within the plat directly east of the Project (The Ridge at Bowman Creek) are generally 60 feet in width, and lots within the plat directly south of the Project (Alicia Glen) are generally 50 feet in width; actually, 11 lots of Alicia Glen are less than 50 feet in width. It should be noted that both subdivisions, The Ridge at Bowman Creek (recorded in 1997) and Alicia Glen (recorded in 2014) were platted under King County’s regulations and standards. The Ridge at Bowman Creek was platted and recorded prior to annexation, while the Alicia Glen preliminary plat was approved in King County, and the final plat was completed following the plat’s annexation into the City of Auburn. Staff therefore finds the Project meets this criterion. B. That, because of such special circumstances, the development of the property in strict conformity with the provisions of this title will not allow a reasonable and harmonious use of the property; Staff Analysis: The requested plat modification affects less than 25% of the lots in the plat. Also, at least in part the justification for the subdivision standard requiring corner lots to be platted five feet wider is to accommodate the greater street side yard setback standard without reducing the buildable area within the lots The city’s wider corner lot standards assures uniformity in the building development envelope between all lots including corner and internal lots for consistent aesthetics and open space. Also in the circumstances of this plat, the corner lots (Lots No. 2, 5, 7, and 13) are located at the intersection of a public street and an private access tract, and not two public streets. This results in less likelihood that the City would have to acquire additional right-of-way to widen the private access tract in the future and reduce the lot area. Given that each corner lot is proposed to meet the minimum lot width for the R-5 zoning district (50 ft.), and the future placement of homes and accessory residential structures will be required to meet the 10 foot street side setback as conditioned under ‘Recommended Conditions of Approval’ No. 1 below. Strict conformity of the ACC 17.14.090(D) would inhibit a reasonable site layout. The alternative of denial of the plat modification may ultimately result in the loss of lots and reduction in density or modifying the plat layout such that the corner lots are platted five feet wider while other lots fall below the 50 foot lot width, thus requiring an administrative variance. Staff therefore finds the Project meets this criterion. C. That the modification, if granted, will not alter the character of the neighborhood, or be detrimental to surrounding properties in which the property is located; Staff Analysis: The requested modification will have imperceptible effect on the character of the neighborhood and will not be detrimental to surrounding properties. Staff therefore finds the Project meets this criterion. 22 of 189 D. Such modification will not be materially detrimental to the implementation of the policies and objectives of the comprehensive land use, transportation and utility comprehensive plans of the city; Staff Analysis: Approval of the plat modification request will not have any detrimental effects on any of the City’s comprehensive plans, as analyzed under ‘Preliminary Plat Conclusions’, above. Staff therefore finds the Project meets this criterion. E. Literal interpretation of the provisions of this title would deprive the applicant of rights commonly enjoyed by other properties in the same zoning district; Staff Analysis: Properties to the east and south of the Project were developed under King County’s regulations and standards. The previously developed plat of Alicia Glen, recorded in 2014, features lots less than 50 feet (as narrow was 40 feet in width). Therefore, granting the modification will provide the owner with development rights and privileges permitted to other properties in the vicinity. Staff therefore finds the Project meets this criterion. F. The approval of the modification will be consistent with the purpose of this title; Staff Analysis: The purpose of Title 17 ACC ‘Land Adjustments and Divisions’ is shown and analyzed in Criterion D, above, under ‘Preliminary Plat Conclusions’. The overall Project layout and approval of this plat modification request is found to be consistent with the purposes of this title. Staff therefore finds the Project meets this criterion. G. The modification cannot lessen the requirements of the zoning ordinance. Any such modification must be processed as a variance pursuant to ACC 18.70.010. Staff Analysis: The plat modification request is not modifying any requirements of Title 18 ACC, ‘Zoning’. Staff therefore finds the Project meets this criterion. 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. 23 of 189 One Deviation was requested: 1. To increase the maximum road grade of SE 301st Pl. and the emergency vehicle and pedestrian access tract (Tract D) from 8% to 10% (Exhibit 12). The City Engineer has reviewed the Deviation request and conditionally recommends approval to the Hearing Examiner, due to the existing grade of SE 301st Pl. to the east and 124th Ave. SE to the west; see Condition no. 2 under ‘Recommended Conditions of Approval’, below. STAFF RECOMMENDATION: Staff recommends approval of the Knudson Preliminary Plat, the Plat Modification request and the Engineering Deviation request, subject to the information contained in this Staff Report, the attached exhibits, and the 15 recommended conditions of approval below. RECOMMENDED CONDITIONS OF APPROVAL: 1. The plat modification request regarding of the minimum lot width of the corner lots is approved for proposed Lots No. 2, 5, 7, and 13 as shown on the “Preliminary Civil Plans”, D.R. Strong Consulting Engineers, Inc., June 21, 2019 (or as may be renumbered). All other zoning development standards must be met. 2. The application for a deviation from the Engineering Design Standards (COADS 10.02.4), to increase the maximum road grade from 8% to 10% on SE 301st Pl. and on the emergency vehicle access road is approved. The City Engineer supports and recommends to the Hearing Examiner approval due to the existing grade of SE 301st Pl to the east and 124th Ave. SE to the west. 3. 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. Also, the cul-de-sac shall be posted “No Parking” around the entire perimeter. The posting shall be in accordance with the City of Auburn Engineering Design Standards. 4. 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 (ECOLOGY) for a General Storm Permit, as required for all projects over 1 acre in size. 5. Prior to City approval of the civil plans under the FAC, the existing on-site septic system shall be abandoned in accordance with the King County Health Department requirements and documentation of the approved abandonment from the Health Department shall be provided to the City. 6. Prior to City approval of the civil plans under the FAC, the existing water well(s) shall be abandoned in accordance the Washington State and the King County Health Department requirements and the applicant shall execute with the City of Auburn a service agreement prohibiting the installation of irrigation wells(s) and other requirements, pursuant to ACC 24 of 189 13.06.150, “Required connections– Existing wells”. 7. 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), identifies a portion of the site is located in a “High Risk” area for archaeological resources and that a cultural resources survey is “highly advised”. As a result of this likelihood, prior to City approval of the civic plans under the FAC or other approvals authorizing earthwork or ground disturbing activities, the Applicant shall prepare a cultural resources investigation report meeting the guidelines of the Washington Department of Archaeology and Historic Preservation (DAHP) and provide it to the City of Auburn, Muckleshoot Indian Tribe, and DAHP for review. The report shall assess the likelihood of the presence of culturally significant resources and identify the recommended mitigation measures to be implemented if resources are discovered. The Applicant shall then implement these recommendations and, if any cultural resources are discovered during construction activities, shall immediately halt all construction activities in the vicinity and notify the City of Auburn, Muckleshoot Indian Tribe, and DAHP. Treatment and preservation of any cultural resources shall then be coordinated with these agencies. 8. If groundwater is encountered during construction in the proposed stormwater detention pond that appears that it will impact the live storage capacity of the detention pond, the City of Auburn will stop construction and may require groundwater monitoring and will require redesign of the facility as necessary to account for observed groundwater. Depending on the groundwater seepage rates encountered, water elevation observed, the time of year or other possible factors involved, construction may not commence again until an updated pond design and revised City of Auburn Facilities Extension Agreement (FAC) is approved by the City of Auburn. 9. The dividing wall that is proposed in the stormwater detention/management pond and shown on Preliminary Civil Plans”, D.R. Strong Consulting Engineers, Inc., June 21, 2019 shall be constructed of structural reinforced concrete. The walls shall be designed and stamped by a structural engineer licensed in the State of Washington. 10. Prior to City approval of the civil plans under the FAC, the plan shall include a landscaping plan. This plan shall show portion of the stormwater pond tract located between the westernmost retaining wall and the back of the right-of-way of 124th St. SE will be landscaped with shallow-rooted shrubs and groundcover. 11. Prior to final plat approval a note shall be placed on the Final Plat indicating that the Knudson Plat Homeowner’s Association and its heirs and successors shall maintain those portions of the tracts containing stormwater ponds and specifically the portions located outside the fenced pond boundaries, or if no fence is provided, outside the 10-year stormwater surface elevation, as determined by the City Engineer. Additionally, the Covenants, Conditions, and Restrictions (CC&Rs) to be reviewed by the City shall also address this maintenance responsibility. 12. 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). 25 of 189 13. If at the time of FINAL PLAT application, the nature and location of the depicted occupation features remain unchanged and/or unresolved, then per RCW 58.17.255, a “survey discrepancy note” shall be placed on the face of the FINAL SHORT PLAT similar to the following example: SURVEY DISCREPANCY NOTE: EXISTING FENCES, RETAINING WALL AND ROCKERY HAVE BEEN SHOWN PURSUANT TO RCW 58.17.255 AND SHALL BE DISCLOSED IN THE TITLE REPORT PREPARED BY THE TITLE INSURER AND ISSUED AFTER THE FILING OF THIS PLAT 14. Prior to final plat approval, the emergency vehicle access tracts (Tract C and D) must be completed and opened to the public street (124th Ave. SE). 15. Tracts A and B are private access tract (joint use driveway) and will be owned and maintained by the HOA. Tract C is a private access (joint use driveway), and partly an emergency vehicle access, and pedestrian access which will be owned and maintained by the HOA. Tract D is a continuation of emergency vehicle and pedestrian access tract in Tract C. An ingress and egress easement, or other instrument as approved by the City, over Tracts C and D must be granted to the City of Auburn, for the purpose of accessing Tract E (stormwater pond), providing emergency services, and pedestrian access to 124th Ave SE. 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 by Harbour Homes, dated November 15, 2018 Exhibit 4. Combined Notice of Application, DNS, and Notice of Public Hearing, completed SEPA Checklist application, and Public Notice Documents Exhibit 5. Written Comment(s) Received and City Response(s) Exhibit 6. Preliminary Civil Plans, D.R. Strong Consulting Engineers, Inc., June 21, 2019 Exhibit 7. Wetland, Fish, and Wildlife Habitat Assessment, Soundview Consultants, August 22, 2018 Exhibit 8. Geotechnical Report, Earth Solutions NW, LLC, April 2, 2019 Exhibit 9. Preliminary Stormwater Site Plan, D.R. Strong Consulting Engineers, Inc., June 19, 2019 Exhibit 10. School Walkway Analysis, D.R. Strong Consulting Engineers, November 9, 2018 Exhibit 11. Plat Modification Request Letter, D.R. Strong Consulting Engineers, Inc., August 13, 2019 Exhibit 12. Engineering Deviation Request & COA Recommend Approval Letter, D.R. Strong Consulting Engineers, Inc., June 19, 2019 26 of 189 Prepared by Alexandria Teague, AICP, Planner II 27 of 189 Exhibit 2 Vicinity Map 28 of 189 Exhibit 3 Completed Prelimary Plat App 29 of 189 30 of 189 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 ___________________ ___________________ 31 of 189 NOTICE OF APPLICATION (NOA) NOTICE OF PUBLIC HEARING (NOH) and DETERMINATION OF NON-SIGNIFICANCE (DNS) Knudson 17-Lot Preliminary Plat SEP19-0012/PLT18-0006 The City of Auburn is issuing a Notice of Application (NOA), Notice of Public Hearing (NOH), and Determination of Non-Significance (DNS) for the following described project. The project application materials and listed studies may be reviewed at the Auburn Department of Community Development at 1 E Main St., 2nd Floor, Customer Service Center, Auburn, WA 98001 and by visiting www.auburnwa.gov/landuse. Proposal: Preliminary plat application to subdivide 3.31 acres into 17 single-family residential lots. The site is zoned R-5, Residential, which allows 4-5 dwelling units per acre. The proposed lots range in size from 4,668 square feet (SF) to 7,687 SF. Roadways to be constructed include extension of SE 301st Pl. (from The Ridge at Willow Park Subdivision) to form a cul-de-sac, three (3) new private access tracts stemming off of SE 301st Pl. SE, and one (1) emergency/pedestrian access tract connecting to 124th Ave. SE. Water and sewer will be extended through the site to service each lot. Location: The project site is adjacent to 124th Ave. SE, just north of SE 302nd Pl. and west of SE 301st Pl., within SE ¼ of Section 4, Township 21, Range 5. King County Assessor Parcel No. 0421059034. Notice of Application: August 28, 2019 Application Complete: December 11, 2018 Permit Application: November 15, 2018 File Nos. SEP19-0012 PLT18-0006 Applicant: Jamie Waltier Harbour Homes, LLC 400 N 34th St. Seattle, WA 98103 Applicant’s Representative: Maher Joudi D.R. Strong Consulting Engineers, Inc. 620 7th Ave. Kirkland, WA 98033 Property Owner: Gerald Knudson 30106 124th Ave. SE Auburn, WA 98092 Studies/Plans Submitted With Application: x Revised SEPA Checklist, D.R. Strong Consulting Engineers, Inc., dated August 13, 2019, received August 14, 2019 x Preliminary Civil Plans, D.R. Strong Consulting Engineers, Inc., dated November 9, 2018, received November 15, 2018, revisions received April 8, 2019,June 24, 2019, and August 14, 2019 Exhibit 4 Combined NOA/DNS and NOH, SEPA Checklist App & Public Notice 32 of 189 NOTICE OF APPLICATION, NOTICE OF PUBLIC HEARING, and DETERMINATION OF NON-SIGNIFICANCE SEP19-0012/PLT18-0006 (Continued) Page 2 of 4 x School Walkway Analysis, D.R. Strong Consulting Engineers, Inc., November 9, 2018, received November 15, 2018 x Geotechnical Report, Earth Solutions NW, LLC, dated October 5, 2018, received November 15, 2018, revisions received April 8, 2019 x Preliminary Stormwater Site Plan, D.R. Strong Consulting Engineers, Inc., dated November 12, 2018, received November 15, 2018, revisions received April 8, 2019 and June 24, 2019 x Wetland, Fish, and Wildlife Habitat Assessment, Soundview Consultants, dated August 22, 2018, received November 15, 2018 Other Permits, Plans, and Approvals Needed: x Public Facility Extension (FAC) / Grading 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. 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 required 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 197-11-340(2); 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 September 12, 2019 to the mailing address of 25 W Main St., Auburn, WA, 98001 or to the email address 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 PM on September 26, 2019. Public Hearing: The Hearing Examiner will conduct a public hearing on the Preliminary Plat in the City Council Chambers, 25 W Main St., Auburn, WA, 98001, on October 16, 2019 at 5:30 PM. Any interested person is invited to appear and express comments or opinions on the proposed project. Written comments may be emailed to the contact person below, mailed attention to the contact person below to 25 W Main St., Auburn WA, 98001, or submitted at the public hearing. For citizens with speech, sight, or hearing disabilities wishing to review documents pertaining to this hearing should contact the person below within 10 calendar days prior to the hearing. Each request will be considered individually according to the type of request, the availability of resources, and the financial ability of the City to provide the requested services or equipment. For questions regarding this project, please contact Alexandria Teague, AICP, Planner II, at planning@auburnwa.gov or 253-931-3088. RESPONSIBLE OFFICIAL: Jeff Tate POSITION/TITLE: Director of Community Development ADDRESS: 25 W Main St. 33 of 189 NOTICE OF APPLICATION, NOTICE OF PUBLIC HEARING, and DETERMINATION OF NON-SIGNIFICANCE SEP19-0012/PLT18-0006 (Continued) Page 3 of 4 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. Vicinity Map August 28, 2019 Jeff Tate 2019.08.22 12:10:49 -07'00' 34 of 189 NOTICE OF APPLICATION, NOTICE OF PUBLIC HEARING, and DETERMINATION OF NON-SIGNIFICANCE SEP19-0012/PLT18-0006 (Continued) Page 4 of 4 Proposed Preliminary Plat Layout 35 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 1 of 13 SEPA ENVIRONMENTAL CHECKLIST Purpose of checklist: Governmental agencies use this checklist to help determine whether the environmental impacts of your proposal are significant. This information is also helpful to determine if available avoidance, minimization or compensatory mitigation measures will address the probable significant impacts or if an environmental impact statement will be prepared to further analyze the proposal. Instructions for applicants: This environmental checklist asks you to describe some basic information about your proposal. Please answer each question accurately and carefully, to the best of your knowledge. You may need to consult with an agency specialist or private consultant for some questions. You may use “not applicable” or "does not apply" only when you can explain why it does not apply and not when the answer is unknown. You may also attach or incorporate by reference additional studies reports. Complete and accurate answers to these questions often avoid delays with the SEPA process as well as later in the decision- making process. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. Attach any additional information that will help describe your proposal or its environmental effects. The agency to which you submit this checklist may ask you to explain your answers or provide additional information reasonably related to determining if there may be significant adverse impact. Instructions for Lead Agencies: Please adjust the format of this template as needed. Additional information may be necessary to evaluate the existing environment, all interrelated aspects of the proposal and an analysis of adverse impacts. The checklist is considered the first but not necessarily the only source of information needed to make an adequate threshold determination. Once a threshold determination is made, the lead agency is responsible for the completeness and accuracy of the checklist and other supporting documents. Use of checklist for nonproject proposals: For nonproject proposals (such as ordinances, regulations, plans and programs), complete the applicable parts of sections A and B plus the SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (part D). Please completely answer all questions that apply and note that the words "project," "applicant," and "property or site" should be read as "proposal," "proponent," and "affected geographic area," respectively. The lead agency may exclude (for non-projects) questions in Part B - Environmental Elements –that do not contribute meaningfully to the analysis of the proposal. A. Background 1. Name of proposed project, if applicable: Knudson Preliminary Plat 2. Name of applicant: Harbour Homes, LLC 36 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 2 of 13 3. Address and phone number of applicant and contact person: Applicant: 400 North 34th St., Suite 300 Seattle, WA 98103 206-315-8130 Contact Person: Maher A. Joudi 620 7th Avenue Kirkland, WA 98033 425-827-3063 4. Date checklist prepared: August 13, 2019 5. Agency requesting checklist: City of Auburn 6. Proposed timing or schedule (including phasing, if applicable): Construction will start upon the receipt of all required building and construction permits. This is estimated to occur in fall of 2019 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. The Project is to construct site improvements for the future construction of 17 single- family residences. 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. Stormwater Site Plan – D.R. STRONG Consulting Engineers, Nov. 9, 2018 Wetland and Fish and Wildlife Habitat Assessment Report – Soundview Consultants, August 22, 2018 Geotechnical Engineering Study – Earth Solutions NW, LLC, October 5, 2018 School Walkway Analysis – DR Strong Consulting Engineers, November 8, 2018 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. Not at this time. 10. List any government approvals or permits that will be needed for your proposal, if known. Deviation Request Approval City of Auburn SEPA Determination City of Auburn Preliminary Subdivision Approval City of Auburn Grading Permit City of Auburn Final Subdivision Approval City of Auburn Building Permits City of Auburn General Construction Stormwater Permit Department of Ecology 11. Give 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. (Lead agencies may modify this form to include additional specific information on project description.) 37 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 3 of 13 The Project is a proposed single-family subdivision of 3.31 acres into 17 new single-family residential lots. The Project is also proposing to connect to SE 301st Place through the provision of a cul-de-sac. An emergency vehicle access easement and connection will be provided to 124th Ave NE. 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 checklist. The Site is in SE ¼ Section 4, Township 21 N, Range 5 E with 124th to the west, SE 301st Place to the east, and single-family residences to the north and south. B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site: (circle one): Flat, rolling, hilly, steep slopes, mountainous, other _____________ In general, the majority of the property has slopes of approximately 10%. Generally, the slope is constant and slopes from east to west. b. What is the steepest slope on the site (approximate percent slope)? There are some isolated areas with slopes nearing 28%. 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 agricultural land of long-term commercial significance and whether the proposal results in removing any of these soils. The soils on the Site are prepared by the U.S. Department of Agriculture, Soil Conservation Service and has classified the Site as Alderwood gravelly sandy loam, slopes 8-15% and Alderwood gravelly sandy loam, slopes 15-30%. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. Per King County iMap, the northwest portion of the Site is identified as an erosion hazard area. However, the geotechnical assessment of the test pit data demonstrates that soil conditions are not susceptible to erosion based on the dense and cemented nature of the native glacial till on th subject site. e. Describe the purpose, type, total area, and approximate quantities and total affected area of any filling, excavation, and grading proposed. Indicate source of fill. The proposed grading will be to construct roads, storm drainage facilities, building pads, etc. The preliminary estimates of earthwork volumes are: 6,200 cubic yards of cut and 15,000 cubic yards of fill. This results in a net fill of 8,800 cubic yards. Needed fill will be supplied from local sources. f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. There could be a short-term increase in the potential for on-site erosion where soils are exposed during Site preparation and construction. However, the Project will 38 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 4 of 13 comply with all applicable erosion control measures, short and long term. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? ±62% of the Site will be covered with impervious surfaces after construction. h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: A temporary erosion control plan will be implemented at the appropriate time. Erosion control measures may include the following: siltation fences, stabilized construction entrance, and other measures which may be required at the time of construction. 2. Air a. What types of emissions to the air would result from the proposal during construction, operation, and maintenance when the project is completed? If any, generally describe and give approximate quantities if known. Short-term emissions will be those associated with construction and Site development activities. These will include dust and emissions from construction equipment. The Project will not result in any known long-term air emissions. b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe. Off-site sources of emissions or odors are those that are typical of residential neighborhoods. These will include automobile emissions from traffic on adjacent roadways and fireplace emissions from nearby homes. c. Proposed measures to reduce or control emissions or other impacts to air, if any: The Washington Clean Air Act requires the use of all known, available, and reasonable means of controlling air pollution, including dust. Construction impacts will not be significant and could be controlled by measures such as washing truck wheels before exiting the Site, and maintaining gravel construction entrances. 3. Water a. Surface Water: 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. Yes, a wetland exists approximately 264 feet NW of the Site. 2) Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. No 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. N/A 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. 39 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 5 of 13 There will be no surface water withdrawals or diversions. 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan. There are no FEMA mapped flood plains within the Site. 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. As long as prescribed BMP's are followed during construction, there is negligible risk of any discharge of waste materials to surface water. b. Ground Water: 1) Will groundwater be withdrawn from a well for drinking water or other purposes? If so, give a general description of the well, proposed uses and approximate quantities withdrawn from the well. Will water be discharged to groundwater? Give general description, purpose, and approximate quantities if known. No ground water will be withdrawn. 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 the following 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) are expected to serve. No waste material is proposed to be discharged into the ground. The Site, containing 17 single-family homes, will be served by public sanitary sewers and a public water system. c. Water runoff (including stormwater): 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 result from the proposed roads, driveways, and roof areas. The runoff will be collected in a series of catch basins and piped to one detention / water quality pond located in Tract E along the western property line. 2) Could waste materials enter ground or surface waters? If so, generally describe. The project runoff will be collected and conveyed to the detention facility before being discharged. 3) Does the proposal alter or otherwise affect drainage patterns in the vicinity of the site? If so, describe. No d. Proposed measures to reduce or control surface, ground, and runoff water, and drainage pattern impacts, if any: A City approved storm drainage system will be designed and implemented in order to mitigate any adverse impacts from storm water runoff. Temporary and permanent drainage facilities will be used to control surface runoff during construction and after development. The Site is located in Groundwater Protection Zone 4, therefore BMP’s will be implemented per ACC 16.10.120(E)(2) 40 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 6 of 13 4. Plants a. Check the types of vegetation found on the site: _X__deciduous tree: alder, maple, aspen, other _X__evergreen tree: fir, cedar, pine, other _X__shrubs _X__grass _ X__pasture ____crop or grain ____Orchards, vineyards or other permanent crops. ____wet soil plants: cattail, buttercup, bullrush, skunk cabbage, other ____water plants: water lily, eelgrass, milfoil, other _X__other types of vegetation b. What kind and amount of vegetation will be removed or altered? All trees, pasture, and other vegetation will be removed. c. List threatened and endangered species known to be on or near the site. None known. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: Street trees and residential landscaping are proposed. e. List all noxious weeds and invasive species known to be on or near the site. None known. 5. Animals a. List any birds and other animals which have been observed on or near the site or are known to be on or near the site. Examples include: birds: hawk, heron, eagle, songbirds, other: mammals: deer, bear, elk, beaver, other: fish: bass, salmon, trout, herring, shellfish, other ________ Songbirds, deer, raccoon, mouse, opossum, mole. b. List any threatened and endangered species known to be on or near the site. No threatened or endangered species are known to be on or near the Site. c. Is the site part of a migration route? If so, explain. Western Washington is in the migration path of a wide variety of non-tropical songbirds, and waterfowl, including many species of geese. d. Proposed measures to preserve or enhance wildlife, if any. None. 41 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 7 of 13 e. List any invasive animal species known to be on or near the site. None known. 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. Electric and Natural Gas, will be used for heating, cooking, etc. b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. No 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: None 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. There are no known on-site environmental health hazards known to exist today, and none will be generated as a direct result of this proposal. 1) Describe any known or possible contamination at the site from present or past uses. None known. 2) Describe existing hazardous chemicals/conditions that might affect project development and design. This includes underground hazardous liquid and gas transmission pipelines located within the project area and in the vicinity. None known 3) Describe any toxic or hazardous chemicals that might be stored, used, or produced during the project's development or construction, or at any time during the operating life of the project. Gasoline will be used to operate construction equipments. 4) Describe special emergency services that might be required. No special emergency services will be required. 5) Proposed measures to reduce or control environmental health hazards, if any: Special measures are not anticipated. b. Noise 1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? The primary source of off-site noise in the area originates from vehicular traffic present on adjacent streets 42 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 8 of 13 2) 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)? Indi- cate what hours noise would come from the site. Short-term impacts will result from the use of construction equipment during construction of the storm drainage conveyance system. Construction will occur during the daylight hours, and in compliance with all noise ordinances. Heavy equipment, hand tools and the transporting of construction materials and equipment generate construction noise. Long-term impacts will be the increase in number of cars in the area due to the construction of these homes. Noise would be present mainly during daytime hours. 3) Proposed measures to reduce or control noise impacts, if any: Construction will be performed during normal daylight hours 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? Will the proposal affect current land uses on nearby or adjacent properties? If so, describe. The Site and adjacent properties are used as single family residential. Current landuses on nearby or adjacent properties will not be affected. b. Has the project site been used as working farmlands or working forest lands? If so, describe. How much agricultural or forest land of long-term commercial significance will be converted to other uses as a result of the proposal, if any? If resource lands have not been designated, how many acres in farmland or forest land tax status will be converted to nonfarm or nonforest use? Not to our knowledge. 1) Will the proposal affect or be affected by surrounding working farm or forest land normal business operations, such as oversize equipment access, the application of pesticides, tilling, and harvesting? If so, how: Not to our knowledge. c. Describe any structures on the site. The western half of the parcel is currently occupied by one single-family residence and associated outbuildings. The eastern half of the Site is undeveloped. A gravel driveway provides access to the Site. d. Will any structures be demolished? If so, what? All existing structures described above will be demolished. e. What is the current zoning classification of the site? R-5 f. What is the current comprehensive plan designation of the site? Single Family Residential g. If applicable, what is the current shoreline master program designation of the site? N/A 43 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 9 of 13 h. Has any part of the site been classified as a critical area by the city or county? If so, specify. The Site is in Groundwater Protection Zone 4. i. Approximately how many people would reside or work in the completed project? Approximately 44 people (2.57 x 17 households) would reside in the completed project. j. Approximately how many people would the completed project displace? Approximately 3 people (2.57 x 1 household). k. Proposed measures to avoid or reduce displacement impacts, if any: None L. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: The proposed development is compatible with the prescribed land use codes and designations for this Site. The development is consistent with the projected land use of this property. m. Proposed measures to reduce or control impacts to agricultural and forest lands of long-term commercial significance, if any: None. 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, mid- dle, or low-income housing. The completed project will provide 17 detached single-family residential homes. Homes will be priced with a market orientation to the middle-income level homebuyer. b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low-income housing. One middle income unit would be eliminated by the proposed Project. c. Proposed measures to reduce or control housing impacts, if any: None 10. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? The maximum building height will conform to City of Auburn building and zoning codes. The exterior building materials will be primarily wood or composite siding. b. What views in the immediate vicinity would be altered or obstructed? Views in the vicinity are not likely to be enhanced, extended or obstructed by development of this Project. 44 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 10 of 13 b. Proposed measures to reduce or control aesthetic impacts, if any: The location of the buildings adheres to or exceeds the minimum setback requirements of the zoning district. The landscaping will be installed at the completion of building and paving construction. A Homeowners Association will maintain the landscaping and common elements. 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Light and glare will be produced from building lighting. Light will also be produced from vehicles using the Site. The light and glare will occur primarily in the evening and before dawn. b. Could light or glare from the finished project be a safety hazard or interfere with views? Light and glare from the Project will not cause hazards or interfere with views. c. What existing off-site sources of light or glare may affect your proposal? The primary off-site source of light and glare will be from vehicles traveling along the area roadways. Also, the adjacent residential uses and streetlights may create light and glare. d. Proposed measures to reduce or control light and glare impacts, if any: Street lighting, when deemed necessary, will be installed in a manner that directs the light downward. 12. Recreation a. What designated and informal recreational opportunities are in the immediate vicinity? The closest public park, Auburndale 2 (9.34 acres in size), is 0.91 miles away from the site. b. Would the proposed project displace any existing recreational uses? If so, describe. No. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: Park impact fees, if any, will be paid as required by City provisions. 13. Historic and cultural preservation a. Are there any buildings, structures, or sites, located on or near the site that are over 45 years old listed in or eligible for listing in national, state, or local preservation registers ? If so, specifically describe. None found in Washington State Department of Archaeology & Historic Preservation database. Washington Information System for Architectural & Archaeological Records Data (WISAARD) did not return any historical information. b. Are there any landmarks, features, or other evidence of Indian or historic use or occupation? This may include human burials or old cemeteries. Are there any material evidence, artifacts, or areas of cultural importance on or near the site? Please list any professional studies conducted at the site to identify such resources. 45 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 11 of 13 Unknown, no studies have been conducted to date. c. Describe the methods used to assess the potential impacts to cultural and historic resources on or near the project site. Examples include consultation with tribes and the department of archeology and historic preservation, archaeological surveys, historic maps, GIS data, etc. Per the Washington State Department of Archeology and Historic Preservation (DAHP) predictive model, Washington Information System for Architectural and Archeological Records Data (WISAARD), a small portion of the site (western line) is located in a “High Risk” area for archeological resources and a cultural resources study is “highly advised” but not required. City of Auburn will impose a preliminary plat condition of approval indicating that a cultural resources investigation report meeting the DAHP guidelines will be required prior to issuance of any grading or FAC permits. A report will be prepared prior to that time as required by the condition. d. Proposed measures to avoid, minimize, or compensate for loss, changes to, and disturbance to resources. Please include plans for the above and any permits that may be required. There are no known impacts. If an archeological Site is found during the course of construction, the State Historic Preservation Officer will be notified. See above (part c) for information on required report. 14. Transportation a. Identify public streets and highways serving the site or affected geographic area and describe proposed access to the existing street system. Show on site plans, if any. 124th Avenue SE is the primary road currently leading to the Site. Access the proposed subdivision will be from SE 301st Place. Vehicles will travel east on SE 301st Place and south on 127th Place SE to SE 304th Street. SE 304th will connect travelers to SR18 to the east, 124th Avenue SE or 104th Avenue SE to the west. b. Is the site or affected geographic area currently served by public transit? If so, generally describe. If not, what is the approximate distance to the nearest transit stop? Yes, there are several Metro bus stops along 124th Ave SE to both the north and south of the site. The nearest stop is just south of SE 302nd Place, on the east side of 124th Avenue SE, approximately 400 feet south of the proposed pedestrian connection to 124th. Another stop exists approximately 700 feet north, just north SE 300th Way. c. How many additional parking spaces would the completed project or non-project proposal have? How many would the project or proposal eliminate? The completed Project will have garage parking spaces as well as driveway parking spaces. Additionally, on street parking on one side of the roadway will be available as driveways allow. Parking spaces associated with the one single family residence will be eliminated. d. Will the proposal require any new or improvements to existing roads, streets, pedestrian, bicycle or state transportation facilities, not including driveways? If so, generally describe (indicate whether public or private). The Project is proposing to provide a cul-de-sac connecting to SE 301st Place. Frontage improvements on 124th Avenue SE will also be provided along with an emergency vehicle and pedestrian connection from the proposed cul de sac to said improvements on 124th. 46 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 12 of 13 e. Will the project or proposal use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No. f. How many vehicular trips per day would be generated by the completed project or proposal? If known, indicate when peak volumes would occur and what percentage of the volume would be trucks (such as commercial and nonpassenger vehicles). What data or transportation models were used to make these estimates? There would be 163 average daily trips per day with approximately 17 AM/PM peak- hour trips. g. Will the proposal interfere with, affect or be affected by the movement of agricultural and forest products on roads or streets in the area? If so, generally describe. Not to our knowledge. h. Proposed measures to reduce or control transportation impacts, if any: The development will be pay traffic impact fees per the City of Auburn fee schedule. 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, public transit, health care, schools, other)? If so, generally describe. Yes, the proposal will result in an increase for those services typical of a residential development of this size and nature. The need for public services such as fire and police protection will be typical for a residential development of the size. School age children generated by this development will attend schools in the Auburn School District. b. Proposed measures to reduce or control direct impacts on public services, if any. In addition to payment of annual property taxes by homeowners, the proponent will mitigate the direct impacts of the proposal through traffic and school mitigation programs, if required. 16. Utilities a. Circle utilities currently available at the site: electricity, natural gas, water, refuse service, telephone, sanitary sewer, septic system, other ___________ 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. Sewer and storm will be extended from 124th Avenue SE. Water will be connected at 124th Avenue SE as well as SE 301st Place, thus eliminating the existing dead end main. Telephone, Electricity and Gas will be extended from SE 301st Place unless otherwise deemed necessary by the purveyor to extend from 124th Ave SE. Electricity Puget Sound Energy Natural Gas Puget Sound Energy Water & Sewer City of Auburn Telephone Verizon 47 of 189 SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 13 of 13 C. Signature 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. Signature: ___________________________________________________ Name of signee _________Maher A. Joudi, P.E.________________________ Position and Agency/Organization D.R.STRONG Consulting Engineers______ Date Submitted: ___________ 48 of 189 49 of 189 50 of 189 From:Alexandria Teague To:"cblansfield@auburn.wednet.edu"; "mayor@algonawa.gov"; "brian.davis@cityoffederalway.com"; "jdodge@ci.pacific.wa.us"; "paan461@ecy.wa.gov"; "sepaunit@ecy.wa.gov"; "MARI461@ECY.WA.GOV"; "sepacenter@dnr.wa.gov"; "jim.chan@kingcounty.gov"; "hubenbj@dshs.wa.gov"; "tosborne@lakehaven.org"; "jmartinson@dieringer.wednet.edu"; "kbush@mbaks.com"; "Karen.walter@muckleshoot.nsn.us"; "shirlee.tan@kingcounty.gov"; "tanya-nascimento@fwps.org"; "John.Graves@fema.dhs.gov"; "tim@futurewise.org"; "Valerie.Garza@kingcounty.gov"; "Planning@KentWA.gov"; "lisa.tylor@kent.k12.wa.us"; "josh.baldi@kingcounty.gov"; "Steve.Bleifuhs@kingcounty.gov"; "beth.humphreys@kingcounty.gov"; "laila.mcclinton@kingcounty.gov"; "pazookr@wsdot.wa.gov"; "maint.roads@kingcounty.gov"; "kstanphill@pinnacleliving.com"; "jgreene@kingcounty.gov"; "Jeffrey.Watson@muckleshoot.nsn.us"; "Krongthip Sangkapreecha"; "Rob@muckleshoot.nsn.us"; "laura.murphy@muckleshoot.nsn.us"; "sepa@dahp.wa.gov"; "gretchen.kaehler@dahp.wa.gov"; "marsha.huebner@co.pierce.wa.us"; "rory.grindley@co.pierce.wa.us"; "bhan@piercecounty.org"; "vodopichj@ci.bonney-lake.wa.us"; "jeff.payne@pse.com"; "James.H.Carsner@usace.army.mil"; "SEPA@pscleanair.org"; "perry.weinberg@soundtransit.org"; "rob.ryan@wa.usda.gov"; Karen Stewart VRFA; "reviewteam@commerce.wa.gov"; "Larry.Fisher@dfw.wa.gov"; "mindy@wecprotects.org"; "SEPA.reviewteam@doh.wa.gov" Cc:Shannon Howard Bcc:Planning-1; Alexandria Teague Subject:SEP19-0012 - Knudson 17-Lot Preliminary Plat (PLT18-0006) Date:Wednesday, August 28, 2019 4:07:56 PM Attachments:SEP19-0012 Revised SEPA Checklist.pdf SEP19-0012 PLT18-0006 NOA_NOH_DNS Signed.pdf Good afternoon, Please see the combined Notice of Application, SEPA DNS, and Notice of Public Hearing, and SEPA Checklist for a proposed 17-Lot preliminary plat. Sincerely, Alexandria Alexandria D. Teague, Planner II Community Development City of Auburn | www.auburnwa.gov 253.931.3088 | ateague@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 | https://www.surveymonkey.com/r/XNSL95J Application Forms | http://www.auburnwa.gov/services/resource_library/forms.htm Zoning Maps | http://www.auburnwa.gov/services/resource_library/maps.htm 51 of 189 From:Alexandria Teague To:"separegister@ecy.wa.gov" Bcc:Alexandria Teague; "jwaltier@harbourhomes.com"; "maher.joudi@drstrong.com" Subject:SEP19-0012 - Knudson 17-Lot Preliminary Plat (PLT18-0006) Date:Wednesday, August 28, 2019 4:04:53 PM Attachments:SEP19-0012 Revised SEPA Checklist.pdf SEP19-0012 PLT18-0006 NOA_NOH_DNS Signed.pdf Good afternoon, Please see the combined Notice of Application, SEPA DNS, Notice of Public Hearing, and the SEPA Checklist for a proposed 17-Lot preliminary plat. Sincerely, Alexandria Alexandria D. Teague, Planner II Community Development City of Auburn | www.auburnwa.gov 253.931.3088 | ateague@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 | https://www.surveymonkey.com/r/XNSL95J Application Forms | http://www.auburnwa.gov/services/resource_library/forms.htm Zoning Maps | http://www.auburnwa.gov/services/resource_library/maps.htm 52 of 189 From:Fisher, Larry D (DFW) To:Alexandria Teague Subject:RE: SEP19-0012 - Knudson 17-Lot Preliminary Plat (PLT18-0006) Date:Thursday, August 29, 2019 11:32:23 AM CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments Thank you for providing the file links. I managed to find the discharge point in the civil plans. However, that information is required to be provided in the SEPA checklist, so it is not necessary to look it up separately. Larry Fisher WDFW Area Habitat Biologist 16018 Mill Creek Boulevard Mill Creek, WA 98012 Cell: 425-449-6790 – Please note phone change to just my cell phone. <'){{}}>< <'){{}}>< From: Alexandria Teague <ateague@auburnwa.gov> Sent: Thursday, August 29, 2019 11:09 AM To: Fisher, Larry D (DFW) <Larry.Fisher@dfw.wa.gov> Subject: RE: SEP19-0012 - Knudson 17-Lot Preliminary Plat (PLT18-0006) Good morning Mr. Fisher, Stormwater will be collected and discharged to a stormwater drainage facility located on the northwestern portion of the proposed plat. The public land use notice page for the proposed plat contains a link to the preliminary civil drawings and preliminary stormwater site plan. Sincerely, Alexandria Alexandria D. Teague, AICP, Planner II Community Development City of Auburn | www.auburnwa.gov 253.931.3088 | ateague@auburnwa.gov Exhibit 5 Written Comments Received and City Response 53 of 189 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 | https://www.surveymonkey.com/r/XNSL95J Application Forms | http://www.auburnwa.gov/services/resource_library/forms.htm Zoning Maps | http://www.auburnwa.gov/services/resource_library/maps.htm From: Fisher, Larry D (DFW) <Larry.Fisher@dfw.wa.gov> Sent: Thursday, August 29, 2019 10:43 AM To: Alexandria Teague <ateague@auburnwa.gov> Subject: RE: SEP19-0012 - Knudson 17-Lot Preliminary Plat (PLT18-0006) CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments Hi Alexandria: The checklist lacks adequate detail in the stormwater runoff section to determine where the stormwater will be discharged. If the project requires a new outfall to state waters, a Hydraulic Project Approval will be required from WDFW. Larry Fisher WDFW Area Habitat Biologist 16018 Mill Creek Boulevard Mill Creek, WA 98012 Cell: 425-449-6790 – Please note phone change to just my cell phone. <'){{}}>< <'){{}}>< From: Alexandria Teague <ateague@auburnwa.gov> Sent: Wednesday, August 28, 2019 4:08 PM To: 'cblansfield@auburn.wednet.edu' <cblansfield@auburn.wednet.edu>; 'mayor@algonawa.gov' <mayor@algonawa.gov>; 'brian.davis@cityoffederalway.com' <brian.davis@cityoffederalway.com>; 'jdodge@ci.pacific.wa.us' <jdodge@ci.pacific.wa.us>; 'paan461@ecy.wa.gov' <paan461@ecy.wa.gov>; ECY RE SEPA REGISTER <separegister@ecy.wa.gov>; Sandercock, Maria (ECY) <MARI461@ECY.WA.GOV>; DNR RE SEPACENTER <SEPACENTER@dnr.wa.gov>; 'jim.chan@kingcounty.gov' <jim.chan@kingcounty.gov>; Hubenthal, Bob (DSHS/FFA) 54 of 189 <hubenbj@dshs.wa.gov>; 'tosborne@lakehaven.org' <tosborne@lakehaven.org>; 'jmartinson@dieringer.wednet.edu' <jmartinson@dieringer.wednet.edu>; 'kbush@mbaks.com' <kbush@mbaks.com>; 'Karen.walter@muckleshoot.nsn.us' <Karen.walter@muckleshoot.nsn.us>; 'shirlee.tan@kingcounty.gov' <shirlee.tan@kingcounty.gov>; 'tanya-nascimento@fwps.org' <tanya- nascimento@fwps.org>; 'John.Graves@fema.dhs.gov' <John.Graves@fema.dhs.gov>; 'tim@futurewise.org' <tim@futurewise.org>; 'Valerie.Garza@kingcounty.gov' <Valerie.Garza@kingcounty.gov>; 'Planning@KentWA.gov' <Planning@KentWA.gov>; 'lisa.tylor@kent.k12.wa.us' <lisa.tylor@kent.k12.wa.us>; 'josh.baldi@kingcounty.gov' <josh.baldi@kingcounty.gov>; 'Steve.Bleifuhs@kingcounty.gov' <Steve.Bleifuhs@kingcounty.gov>; 'beth.humphreys@kingcounty.gov' <beth.humphreys@kingcounty.gov>; 'laila.mcclinton@kingcounty.gov' <laila.mcclinton@kingcounty.gov>; 'pazookr@wsdot.wa.gov' <pazookr@wsdot.wa.gov>; 'maint.roads@kingcounty.gov' <maint.roads@kingcounty.gov>; 'kstanphill@pinnacleliving.com' <kstanphill@pinnacleliving.com>; 'jgreene@kingcounty.gov' <jgreene@kingcounty.gov>; 'Jeffrey.Watson@muckleshoot.nsn.us' <Jeffrey.Watson@muckleshoot.nsn.us>; 'Krongthip Sangkapreecha' <ktsang@muckleshoot.nsn.us>; 'Rob@muckleshoot.nsn.us' <Rob@muckleshoot.nsn.us>; 'laura.murphy@muckleshoot.nsn.us' <laura.murphy@muckleshoot.nsn.us>; SEPA (DAHP) <sepa@dahp.wa.gov>; 'gretchen.kaehler@dahp.wa.gov' <gretchen.kaehler@dahp.wa.gov>; 'marsha.huebner@co.pierce.wa.us' <marsha.huebner@co.pierce.wa.us>; 'rory.grindley@co.pierce.wa.us' <rory.grindley@co.pierce.wa.us>; 'bhan@piercecounty.org' <bhan@piercecounty.org>; Vodopich, John <vodopichj@ci.bonney-lake.wa.us>; 'jeff.payne@pse.com' <jeff.payne@pse.com>; 'James.H.Carsner@usace.army.mil' <James.H.Carsner@usace.army.mil>; 'SEPA@pscleanair.org' <SEPA@pscleanair.org>; 'perry.weinberg@soundtransit.org' <perry.weinberg@soundtransit.org>; 'rob.ryan@wa.usda.gov' <rob.ryan@wa.usda.gov>; Karen Stewart VRFA <karen.stewart@vrfa.org>; COM GMU Review Team <reviewteam@commerce.wa.gov>; Fisher, Larry D (DFW) <Larry.Fisher@dfw.wa.gov>; 'mindy@wecprotects.org' <mindy@wecprotects.org>; DOH EPH SEPA <SEPA.reviewteam@doh.wa.gov> Cc: Shannon Howard <showard@auburnwa.gov> Subject: SEP19-0012 - Knudson 17-Lot Preliminary Plat (PLT18-0006) Good afternoon, Please see the combined Notice of Application, SEPA DNS, and Notice of Public Hearing, and SEPA Checklist for a proposed 17-Lot preliminary plat. Sincerely, Alexandria Alexandria D. Teague, Planner II Community Development City of Auburn | www.auburnwa.gov 253.931.3088 | ateague@auburnwa.gov 55 of 189 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 | https://www.surveymonkey.com/r/XNSL95J Application Forms | http://www.auburnwa.gov/services/resource_library/forms.htm Zoning Maps | http://www.auburnwa.gov/services/resource_library/maps.htm This message is private and privileged. If you are not the person meant to receive this message, please let the sender know, then delete it. Please do not copy or send it to anyone else. This message is private and privileged. If you are not the person meant to receive this message, please let the sender know, then delete it. Please do not copy or send it to anyone else. 56 of 189 NSER ISS E FORP I N G O E R DETS REE N G INELA 45232 O R ETAT EHAM F OT G NIHASW I D U OJA. GRAPHIC SCALE 0 15 30 60 1 INCH = 30 FT. ex gg 57 of 189 NSER ISS E FORP I N G O E R DETS REE N G INELA 45232 O R ETAT EHAM F OT G NIHASW I D U OJA. GRAPHIC SCALE 0 15 30 60 1 INCH = 30 FT. Exhibit 6 Preliminary Civil Plans 58 of 189 NSER ISS E FORP I N G O E R DETS REE N G INELA 45232 O R ETAT EHAM F OT G NIHASW I D U OJA. GRAPHIC SCALE 0 10 20 40 1 INCH = 20 FT. 59 of 189 SS SS SS SS SDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSD SDSDSDSD SD SD SDSDSDSDSDSDSDSDSDSDSDSDNSER ISS E FORP I N G O E R DETS REE N G INELA 45232 O R ETAT EHAM F OT G NIHASW I D U OJA. GRAPHIC SCALE 0 10 20 40 1 INCH = 20 FT. 60 of 189 NSER ISS E FORP I N G O E R DETS REE N G INELA 45232 O R ETAT EHAM F OT G NIHASW I D U OJA. 0 0 HORIZONTAL VERTICAL 10 20 40 1 INCH = 20 FT. 2.5 5 10 1 INCH = 5 FT. 61 of 189 NSER ISS E FORP I N G O E R DETS REE N G INELA 45232 O R ETAT EHAM F OT G NIHASW I D U OJA. 0 0 HORIZONTAL VERTICAL 10 20 40 1 INCH = 20 FT. 2.5 5 10 1 INCH = 5 FT. 62 of 189 NSER ISS E FORP I N G O E R DETS REE N G INELA 45232 O R ETAT EHAM F OT G NIHASW I D U OJA. 0 0 HORIZONTAL VERTICAL 10 20 40 1 INCH = 20 FT. 2.5 5 10 1 INCH = 5 FT. 63 of 189 NSER ISS E FORP I N G O E R DETS REE N G INELA 45232 O R ETAT EHAM F OT G NIHASW I D U OJA. GRAPHIC SCALE 0 10 20 40 1 INCH = 20 FT. GRAPHIC SCALE 0 20 40 80 1 INCH = 40 FT. 64 of 189 SD SD SDSDSDSDSD SD SD SD SD SD SD SD SD SDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDNSER ISS E FORP I N G O E R DETS REE N G INELA 45232 O R ETAT EHAM F OT G NIHASW I D U OJA. 0 GRAPHIC SCALE 15105 1 INCH = 10 FT. 65 of 189 NSER ISS E FORP I N G O E R DETS REE N G INELA 45232 O R ETAT EHAM F OT G NIHASW I D U OJA. 0 0 HORIZONTAL VERTICAL 10 20 40 1 INCH = 20 FT. 2.5 5 10 1 INCH = 5 FT. 66 of 189 67 of 189 Technical Memorandum To: Harbour Homes – Chris Burrus File Number: 1155.0027 From: Don Babineau, Soundview Consultants LLC Date: August 22, 2018 Re: Wetland and Fish and Wildlife Habitat Assessment 30106 124th Ave. SE, Auburn, WA 98092 Dear Mr. Burrus, Soundview Consultants LLC (SVC) conducted a wetland and fish and wildlife habitat assessment of an approximately 3.20-acre property located at 30106 124th Ave. SE, in Auburn, Washington (Figure 1). The property consists of a parcel located in the Southeast ¼ of Section 4, Township 21 North, Range 5 East, W.M. (King County Tax Parcel Number 0421059034). This assessment was conducted to support a proposed single- family residential development on the subject property. SVC investigated the site to evaluate if any potentially- regulated wetlands, fish and wildlife habitat, or other related sensitive areas are located on or adjacent to the subject property. This Technical Memorandum has been prepared to document the results of this assessment. Figure 1. Subject Property Location. Subject Property Location Exhibit 7 Wetland, Fish, and Wildlife Habitat Assessment 68 of 189 Background Data Prior to the site investigation, staff conducted background research using King County Geographic Information System (GIS) data, City of Auburn GIS data, Washington Department of Fish and Wildlife (WDFW) Priority Habitat and Species (PHS) and SalmonScape mapping tools, the U.S. Fish and Wildlife Service (USFWS) National Wetland Inventory (NWI), Washington Department of Natural Resources (DNR) stream typing map, and Natural Resources Conservation Service (NRCS) Soil Survey (Attachment B). All determinations were made using observable vegetation, hydrology, and soils in conjunction with data from the U.S. Geological Survey (USGS) topographic maps, USFWS, local precipitation data, and various ortho-photographic resources. The City of Auburn, the USFWS Northwest Wetland Inventory map, the WDFW PHS map, and the King County iMap identifies a wetland approximately 0.05 miles (264 feet) to the northwest of the parcel. Field data was taken at one data point (DP-1) within the subject property (see attachment C for map of data plot location). The NRCS Soil Map (Attachment B9) identifies one soil series on the subject property: Alderwood gravelly sandy loam, 6 to 15 percent slopes and 15 to 30 percent slopes. Both Alderwood gravelly sandy loams are moderately well drained soils and are considered non-hydric except for inclusions of depressional landforms in 15 to 30 percent slopes (NRCS, 2001). No other critical areas are identified within 300 feet of the subject site. Precipitation Precipitation data was obtained from the National Oceanic and Atmospheric Administration (NOAA) weather station at the Sea-Tac Airport Station in order to obtain percent of normal precipitation during and preceding the investigation. A summary of data collected is provided in Table 1. Table 1. Precipitation Summary1. Site Visit Date Day of Day Before 1 Week Prior 2 Weeks Prior 30 Days Prior (Observed/Normal)2 Year to Date (Observed/Normal)3 Percent of Normal (Month/Year)4 6/15/18 0.00 0.00 0.25 0.00 0.43/.91 18.96/18.35 4.7/103 1. Precipitation volume provided in inches. Data obtained from NOAA (http://w2.weather.gov/climate/xmacis.php?wfo=sew) 2. 30 days prior precipitation includes accumulated precipitation beginning 30 days before the on-site date(s) 3. Year-to-date precipitation is for the 2017/2018 water year from January 1st to the onsite date(s) 4. Percent of normal shown for both 30 days prior and 2017/2018 water year The data suggests that precipitation during the June 2018 site visit was below statistical normal, with precipitation thirty days prior (0.43 inches) at 47 percent of normal levels (.91 inches). However, the percent of normal for the year to date (18.96 inches) was higher than the statistical normal (18.35 inches). Such conditions were considered in making professional wetland determinations. Methods A formal investigation was performed by qualified SVC scientists on June 15, 2018. The site investigation consisted of a walkthrough visual survey of all accessible areas within 300 feet of the subject property with data collected and evaluated at potential problem areas. All wetland determinations were performed by qualified SVC staff using guidelines established in the Regional Supplement to the Army Corps of Engineers Wetland Delineation Manual Western Mountains, Valleys, and Coast Region (Version 2.0) (USACE). Wetlands, streams, and select fish and wildlife habitats and species are regulated features per Auburn Municipal Code (AMC) Chapter 16.10 and subject to restricted uses/activities under the same title. Wetland presence/absence was determined in accordance with AMC 16.10.080(C) and as outlined in the U.S. Army Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory, 1987) and modified according to 69 of 189 the guidelines established in the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region, Version 2.0 (USACE, 2010). The fish and wildlife habitat assessment was conducted during the same site visit by a qualified fish and wildlife biologist. The experienced biologists made visual observations using stationary and walking survey methods for both aquatic and upland habitats noting any special habitat features or signs of fish and wildlife activity. Results The parcel is developed as a single-family residence with associated infrastructure including detached structures, utilities, driveways and horse paddocks. The parcel consists primarily of compacted horse pasture with a small wooded area along the east and southeast boundaries of the subject property. Vegetation on the subject property is dominated by facultative and upland species including common hawthorn (Crataegus monogyna), black cottonwood (Populus balsamifera), Himalayan blackberry (Rubus armeniacus), and tall buttercup (Ranunculus acris). Topography on the site is generally flat with a gentle slope downward to the east, with elevations ranging between approximately 445 feet in the eastern boundary of the site to 400 feet on the western boundary. The subject property is bounded by 124th Ave. Southeast to the west and single-family residences to the north, east, and south. No potentially-regulated wetlands and/or fish and wildlife habitat were observed on the subject site. At the bottom of the slope on the western border there are several black cottonwoods with patches of creeping buttercup (Ranunculus repens). A data point was collected (DP-1) in this area as it posed the most questions about the site. The data collected confirmed a non-wetland finding (see Attachment C). Visual observations throughout the remaining portions of the site confirmed the lack of wetland presence through the dominance upland and facultative upland plants. Photographs taken the during the site investigation are included in Attachment A. Conclusions No potentially-regulated wetlands, fish and wildlife habitat, or other related sensitive areas were identified on the subject property during the site investigation. Though the City of Auburn and the USFWS Northwest Wetland Inventory map identifies a wetland approximately 0.05 miles (264 feet) to the northwest of the parcel, visual inspection did not identify any wetland indicators. The distance from the subject site to the potential offsite wetland boundary exceeds the largest protective buffers required by AMC 16.10.090(E)(1). As such, it appears that future development of the subject property would be unencumbered by any potentially-regulated onsite wetlands, fish and wildlife habitat, and/or associated buffers. If you have any further questions, please contact us at your earliest convenience. Sincerely, Don Babineau Environmental Planner/Project Manager 70 of 189 References Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical Report Y- 87-1, US Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. Hitchcock, C.L. and A. Cronquist. 1973. Flora of the Pacific Northwest. University of Washington Press. Seattle, Washington. City of Auburn. 2018. Chapter 16.10-Critial Areas. Website: http://www.codepublishing.com/WA/Auburn/?Auburn18/auburn1849.html. Lichvar, R.W., D.L. Banks, W.N. Kirchner, and N.C. Melvin. 2016. The National Wetland Plant List: 2016 wetland ratings. Phytoneuron 2016-30: 1-17. Published 28 April 2016. ISSN 2153 733X. Munsell Color. 2000. Munsell Soil Color Charts. New Windsor, New York. Natural Resources Conservation Service. 2001. Hydric Soils List: King County Area, Washington. U.S. Department of Agriculture. Washington D.C. Reed, P.B., Jr. 1988. National List of Plant Species That Occur in Wetlands: National Summary. U.S. Fish & Wildlife Service. Biol. Rep. 88 (26.9). U.S. Army Corps of Engineers. 2010. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0), ed. J. S. Wakeley, R. W. Lichvar, and C. V. Noble. ERDC/EL TR-10-13. Vicksburg, MS: U.S. Army Engineer Research and Development Center. 71 of 189 Attachment A – Site Photographs Typical Vegetation on Subject Property 72 of 189 Data Point 1 73 of 189 Attachment B – Background Information This attachment includes a USFWS NWI Map (B1); City of Auburn Stream Inventory Map (B2); City of Auburn Wetland Inventory Map (B3); WDFW PHS Map (B4); WDFW SalmonScape Map (B5); DNR Stream Typing Map (B6); USGS Contours Map (B7); King County iMap (B8),and NRCS Soil Survey Map (B9). 74 of 189 Attachment B1 – USFWS NWI Map Subject Property Location 75 of 189 Attachment B2 – City of Auburn Stream Inventory Map Subject Property Location 76 of 189 Attachment B3 – City of Auburn Wetland Inventory Map 77 of 189 Attachment B4 – WDFW PHS Map PHS Map Pictometry, King County, © 2018 Microsoft Corporation © 2018 DigitalGlobe ©CNES (2018) Distribution Airbus DS © 2018 HERE, WDFW King County parcels _Query result 6/12/2018, 11:52:39 AM 0 0.2 0.40.1 mi 0 0.3 0.60.15 km 1:18,018 These data were collected by WDFW staff with contributions from the North Olympic Salmon Coalition and the Friends of the San Juans. | King county Assessor's Office, King County GIS Center | King County | WDFW | Source: USDA NRCS, Esri | Washington Natural Heritage Program http://www.dnr.wa.gov/natural-heritage-pro Soundview Consultants Subject Property Location 78 of 189 Attachment B5 – WDFW SalmonScape Map Subject Property Location 79 of 189 Attachment B6 – DNR Stream Typing Map DNR Stream Typing Pictometry, King County, © 2018 Microsoft Corporation © 2018 DigitalGlobe ©CNES (2018) Distribution Airbus DS © 2018 HERE King County parcels _Query result Streams Type S Type F Type N, Np, Ns U, unknown X, non-typed per WAC 222-16 6/12/2018, 11:48:19 AM 0 0.03 0.050.01 mi 0 0.04 0.080.02 km 1:2,252 These data were collected by WDFW staff with contributions from the North Olympic Salmon Coalition and the Friends of the San Juans. | King county Assessor's Office, King County GIS Center | King County | WDFW | Source: USDA NRCS, Esri | Washington Natural Heritage Program http://www.dnr.wa.gov/natural-heritage-pro Soundview Consultants Subject Property Location 80 of 189 Attachment B7 – USGS Contours Map Topographic Map Sources: Esri, HERE, Garmin, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey, Esri King County parcels _Query result 6/12/2018, 11:23:47 AM 0 0.03 0.050.01 mi 0 0.04 0.080.02 km 1:2,257 These data were collected by WDFW staff with contributions from the North Olympic Salmon Coalition and the Friends of the San Juans. | King county Assessor's Office, King County GIS Center | King County | WDFW | Source: USDA NRCS, Esri | Washington Natural Heritage Program http://www.dnr.wa.gov/natural-heritage-pro Soundview Consultants Subject Property Location 81 of 189 Attachment B8 – King County iMap Subject Property Location 82 of 189 Attachment B9 – NRCS Soil Survey Map 83 of 189 Attachment C – Existing Conditions and Data Point 1 84 of 189 WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region Project/Site: City/County: Sampling Date: Applicant/Owner: State: Sampling Point: Investigator(s): Section, Township, Range: Landform (hillslope, terrace, etc.): Local relief (concave, convex, none): Slope (%): Subregion (LRR): Lat: Long: Datum: Soil Map Unit Name: NWI classification: Are climatic / hydrologic conditions on the site typical for this time of year? Yes No (If no, explain in Remarks.) Are Vegetation , Soil , or Hydrology significantly disturbed? Are “Normal Circumstances” present? Yes 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. Hydrophytic Vegetation Present? Yes No Hydric Soil Present? Yes No Wetland Hydrology Present? Yes No Is the Sampled Area within a Wetland? Yes No Remarks: VEGETATION – Use scientific names of plants. Absolute Dominant Indicator Tree Stratum (Plot size: 30 ft) % Cover Species? Status 1. 2. 3. 4. = Total Cover Sapling/Shrub Stratum (Plot size: 15 ft) 1. 2. 3. 4. 5. = Total Cover Herb Stratum (Plot size: 5 ft) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. = Total Cover Woody Vine Stratum (Plot size: 30 ft) 1. 2. = Total Cover % Bare Ground in Herb Stratum Dominance Test worksheet: Number of Dominant Species That Are OBL, FACW, or FAC: (A) Total Number of Dominant Species Across All Strata: (B) Percent of Dominant Species That Are OBL, FACW, or FAC: (A/B) Prevalence Index worksheet: Total % Cover of: Multiply by: OBL species x 1 = FACW species x 2 = FAC species x 3 = FACU species x 4 = UPL species x 5 = Column Totals: (A) (B) Prevalence Index = B/A = Hydrophytic Vegetation Indicators: Rapid Test for Hydrophytic Vegetation Dominance Test is >50% Prevalence Index is ≤3.01 Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) Wetland Non-Vascular Plants1 Problematic Hydrophytic Vegetation1 (Explain) 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytic Vegetation Present? Yes No Remarks: 1155.0027 - Knudson Auburn / King 06/15/2018 Knutson Harbor Homes WA DP-1 Erin Harker, Richard Peel 4, 21N, 05E Hillslope Convex 10 A2 47.3323152 -122.1755849 WGS 84 Alderwood gravelly sandy loam N/A Not all three wetland criteria were observed. Data collected in horse paddock, compacted area by fence Crataegus monogyna 60 Yes FAC 4 Populus balsamifera 40 Yes FAC 4 100 100% Rubus armeniacus 5 Yes FAC 5 Ranunculus acris 15 Yes FAC 15 0 85 Hydrophytic vegetation criteria observed through the dominance test. 85 of 189 SOIL Sampling Point: Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: Histosol (A1) Sandy Redox (S5) 2 cm Muck (A10) Histic Epipedon (A2) Stripped Matrix (S6) Red Parent Material (TF2) Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) Very Shallow Dark Surface (TF12) Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) Other (Explain in Remarks) Depleted Below Dark Surface (A11) Depleted Matrix (F3) Thick Dark Surface (A12) Redox Dark Surface (F6) 3Indicators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surface (F7) wetland hydrology must be present, Sandy Gleyed Matrix (S4) Redox Depressions (F8) unless disturbed or problematic. Restrictive Layer (if present): Type:________________________________ Depth (inches):________________________ Hydric Soil Present? Yes No Remarks: HYDROLOGY Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) Surface Water (A1) Water-Stained Leaves (B9) (except MLRA Water-Stained Leaves (B9) (MLRA 1, 2, High Water Table (A2) 1, 2, 4A, and 4B) 4A, and 4B) Saturation (A3) Salt Crust (B11) Drainage Patterns (B10) Water Marks (B1) Aquatic Invertebrates (B13) Dry-Season Water Table (C2) Sediment Deposits (B2) Hydrogen Sulfide Odor (C1) Saturation Visible on Aerial Imagery (C9) Drift Deposits (B3) Oxidized Rhizospheres along Living Roots (C3) Geomorphic Position (D2) Algal Mat or Crust (B4) Presence of Reduced Iron (C4) Shallow Aquitard (D3) Iron Deposits (B5) Recent Iron Reduction in Tilled Soils (C6) FAC-Neutral Test (D5) Surface Soil Cracks (B6) Stunted or Stressed Plants (D1) (LRR A) Raised Ant Mounds (D6) (LRR A) Inundation Visible on Aerial Imagery (B7) Other (Explain in Remarks) Frost-Heave Hummocks (D7) Sparsely Vegetated Concave Surface (B8) Field Observations: Surface Water Present? Yes No Depth (inches): Water Table Present? Yes No Depth (inches): Saturation Present? Yes No Depth (inches): (includes capillary fringe) Wetland Hydrology Present? Yes No Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: DP-1 0 - 12 10YR 3/4 100 ----SaLo Sandy Loam No hydric soil criteria observed. No primary or secondary indicators observed. 86 of 189 '&DP-1U Pictometry, King County KNUDSON PROPERTY - EXISTING CONDITIONS ¢ PRELIMINARYINFORMATION ONLYNOT FOR CONSTRUCTION SOUNDVIEW CONSULTANTS LLC ASSUMESNO LIABILITY OR RESPONSIBILITY FORCONSTRUCTION, IMPROVEMENTS, ORESTIMATES BASED ON THIS PLAN SET www.soundviewconsultants.com 2907 Harborview Dr., Suite D, Gig Harbor, WA 98335Phone: (253) 514-8952 Fax: (253) 514-8954 Soundview ConsultantsEnvironmental Assessment • Planning • Land Use Solutions LLC 30106 124TH AVE SEAUBURN, WA 98092 KING COUNTY PARCEL NUMBERS:0421059034 KNUDSON PROPERTY DATE: JOB: BY: SCALE: FIGURE NO. 8/21/2018 1155.00257 DLS 1 0 100 20050 Feet 1 " = 50 ' '&Data Plot Site Boundary 87 of 189 Attachment D – Qualifications All field inspections, jurisdictional wetland determinations, OHW determinations, habitat assessments, and supporting documentation, including this Wetland and Fish and Wildlife Habitat Assessment Technical Memorandum prepared for the Knudson Project, were prepared by, or under the direction of, Don Babineau of SVC. In addition, site inspections and report preparation were performed by Don Babineau, Erin Harker, and Richard Peel. Don Babineau Environmental Planner/Project Manager Professional Experience: >12 years Don Babineau is an Environmental Planner and Project Manager with a diverse background in urban and commercial forestry, land planning, landscape architecture, stormwater monitoring and civil engineering. Don has experience as a Forester with Washington State Department of Natural Resources stream typing and delineating stream protection zones, as well as implementing Washington State’s Habitat Conservation Plan to foster the creation of old-growth forest characteristics on state trust lands. Don earned a Bachelor of Science degree in Forest Ecosystems Management and a Bachelor of Landscape Architecture degree, both from the University of Idaho. Don has been formally trained by the Washington State Department of Ecology in the use of the Washington State Wetland Rating System. In addition, he has received formal training in wetland delineation from the Northwest Environmental Training Center and has experience as certified erosion and sediment control lead (CESCL). He is also a Pierce County qualified Pr ofessional Forester. Erin Harker Staff Scientist Professional Experience: 3 years Erin Harker is a Staff Scientist with diverse ecological experience in both field and laboratory settings in the Pacific Northwest. She has gained hands-on experience involving research on water quality, salmon runs, restoration project performance, and marine mammal hydro-acoustics. Erin is proficient in collecting and analyzing environmental data; riparian restoration and wetland mitigation monitoring principles and techniques; analyzing local, state, and federal environmental code and regulations; and technical writing. Erin has additional experience engaging students in a suite of environmental curriculums. She currently assists clients through the various stages of land use planning by conducting environmental code analysis; preparing environmental assessments, mitigation reports, and biological evaluations; and completing permit applications. Erin graduated from Western Washington University with a Bachelor of Science degree in Environmental Science with a Marine Ecology focus. She has received formal training through the WSDOE and Coastal Training Program in conducting forage fish surveys; amphibian identification and survey guidance; using the credit-debit system for estimating wetland mitigation needs, determining the ordinary high water mark; Puget Sound coastal processes; conducting eelgrass delineations; using the 2014 wetland rating system; and using field indicators for hydric soils. 88 of 189 EarthSolutionsNWLLC EarthSolutions NW LLC 1805 - 136th Place N.E., Suite 201 Bellevue, WA98005 (425) 449-4704 Fax (425) 449-4711 www.earthsolutionsnw.com Geotechnical Engineering Construction Observation/Testing Environmental Services GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL DEVELOPMENT 30106 - 124 AVENUE SOUTHEAST AUBURN, WASHINGTON ES-6204 TH Exhibit 8 Geotechnical Report 89 of 189 90 of 189 91 of 189 92 of 189 93 of 189 94 of 189 95 of 189 96 of 189 97 of 189 98 of 189 99 of 189 100 of 189 101 of 189 102 of 189 103 of 189 104 of 189 105 of 189 Drwn. Checked Date Date Proj. No. Plate Earth Solutions NWLLC Geotechnical Engineering,Construction EarthSolutionsNWLLC EarthSolutions NW LLC Observation/Testing and Environmental Services Vicinity Map Knudson Auburn, Washington MRS SHA 09/24/2018 Sept. 2018 6204 1 NORTH NOTE: This plate may contain areas of color. ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. Reference: King County, Washington Map 746 By The Thomas Guide Rand McNally 32nd Edition SITE 106 of 189 Plate Proj. No. Date Checked By Drwn. ByEarth Solutions NWLLCGeotechnical Engineering,ConstructionObservation/Testing and Environmental ServicesEarthSolutionsNWLLCEarthSolutionsNWLLCMRS SHA 04/01/2019 6204 2Test Pit Location PlanKnudsonAuburn, Washington NORTH NOTE: This plate may contain areas of color. ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. NOTE: The graphics shown on this plate are not intended for design purposes or precise scale measurements, but only to illustrate the approximate test locations relative to the approximate locations of existing and / or proposed site features. The information illustrated is largely based on data provided by the client at the time of our study. ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. 0 40 80 160 Scale in Feet1"=80' LEGEND Approximate Location of ESNW Test Pit, Proj. No. ES-6204, Sept. 2018 and Mar. 2019 Subject Site Proposed Lot Number TP-1 TP-2 TP-3 TP-4 TP-1 S.E. 301ST PLACE 124TH AVENUE S.E.Tract BTract A 12 34 56 7 8 9 10 11 12 13 14 15 16 17 10 S.E. 302ND PLACE TP-5 440 430420410 440 430420410 107 of 189 Drwn. Checked Date Date Proj. No. Plate Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC Geotechnical Engineering,Construction Observation/Testing and Environmental Services Retaining Wall Drainage Detail Knudson Auburn, Washington MRS SHA 09/24/2018 Sept. 2018 6204 3 NOTES: Free-draining Backfill should consist of soil having less than 5 percent fines. Percent passing No. 4 sieve should be 25 to 75 percent. Sheet Drain may be feasible in lieu of Free-draining Backfill, per ESNW recommendations. Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1-inch Drain Rock. LEGEND: Free-draining Structural Backfill 1-inch Drain Rock 18" Min. Structural Fill Perforated Rigid Drain Pipe (Surround in Drain Rock) SCHEMATIC ONLY - NOT TO SCALE NOT A CONSTRUCTION DRAWING 108 of 189 Drwn. Checked Date Date Proj. No. Plate Earth Solutions NWLLC Geotechnical Engineering,Construction Observation/Testing and Environmental Services EarthSolutionsNWLLC EarthSolutions NW LLC Footing Drain Detail Knudson Auburn, Washington MRS SHA 09/24/2018 Sept. 2018 6204 4 Slope Perforated Rigid Drain Pipe (Surround in Drain Rock) 18" Min. NOTES: Do NOT tie roof downspouts to Footing Drain. Surface Seal to consist of 12" of less permeable, suitable soil. Slope away from building. LEGEND: Surface Seal: native soil or other low-permeability material. 1-inch Drain Rock SCHEMATIC ONLY - NOT TO SCALE NOT A CONSTRUCTION DRAWING 109 of 189 110 of 189 111 of 189 112 of 189 113 of 189 114 of 189 115 of 189 116 of 189 117 of 189 118 of 189 119 of 189 © 2018 D. R. STRONG Consulting Engineers Inc. _________________________________________________________________________ STORMWATER SITE PLAN (SSP) FOR KNUDSON PRELIMINARY PLAT 30106 124th Avenue SE, Auburn, WA – Auburn, Washington DRS Project No. 18042 Auburn Reference No. PLT18-0006 & VAR18-0008 Applicant Property Owner Harbour Homes, LLC Gerald C Knudson 400 N 34th Street, Suite 300 30106 124th Avenue SE Seattle, WA 98103 Seattle, WA 98092 Contact: Jamie Waltier Phone: (206) 246-9456 Phone: (206) 815-8130 Email: jerryk@greenriverconstruction.com Email: jwaltier@harbourhomes,com Engineer D. R. STRONG Consulting Engineers, Inc. 620 7th Avenue Kirkland WA 98033 (425) 827-3063 Report Preparation Date June 19, 2019 06.19.19 Exhibit 9 Preliminary Stormwater Site Plan 120 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page i of ii Stormwater Site Plan Knudson Preliminary Plat City of Auburn KNUDSON PRELIMINARY PLAT STORMWATER SITE PLAN TABLE OF CONTENTS CHAPTER 1 – PROJECT OVERVIEW ........................................................................... 1 CHAPTER 2 – EXISTING CONDITIONS SUMMARY .................................................... 4 Drainage Complaints ................................................................................................... 5 CHAPTER 3 – OFFSITE ANALYSIS .............................................................................. 7 Qualitative Analysis ..................................................................................................... 7 Upstream Analysis ................................................................................................... 7 Downstream Analysis ............................................................................................... 7 Off Site Analysis Drainage System Table .................................................................. 11 Photos ....................................................................................................................... 14 CHAPTER 4 – PERMANENT STORMWATER CONTROL PLAN ............................... 26 Threshold Discharge Areas ....................................................................................... 27 Pre-Developed Site Hydrology .................................................................................. 28 Developed Site Hydrology ......................................................................................... 28 CHAPTER 5 – DISCUSSION OF MINIMUM REQUIREMENTS ................................... 35 Minimum Requirement #1: Preparation of Stormwater Site Plans ............................. 36 Minimum Requirement #2: Construction Stormwater Pollution Prevention (SWPP)...................................................................................................................... 36 Minimum Requirement #3: Source Control of Pollution ............................................. 38 Mimimum Requirement #4: Preservation of Natural Drainage Systems and Outfalls ...................................................................................................................... 38 Minimum Requirement #5: On-Site Stormwater Management .................................. 39 Minimum Requirement #6: Runoff Treatment ............................................................ 42 Minimum Requirement #7: Flow Control.................................................................... 42 Minimum Requirement #8: Wetlands Protection ........................................................ 43 Minimum Requirement #9: Operation and Maintenance............................................ 43 Minimum Requirement #10: Off-Site Analysis and Mitigation .................................... 43 List of Figures Figure 1 Vicinity Map ....................................................................................................... 2 Figure 2 Soil Map ............................................................................................................ 6 Figure 3 Downstream Map ............................................................................................ 10 Figure 4 iMAP Contour Map .......................................................................................... 25 Figure 5 Pre-Developed Area Map ................................................................................ 33 Figure 6 Developed Area Map ...................................................................................... 34 121 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page ii of ii Stormwater Site Plan Knudson Preliminary Plat City of Auburn Appendices APPENDIX A MAINTENANCE AND OPERATIONS MANUAL APPENDIX B SWPPP APPENDIX C HYDRAULIC/HYDROLOGIC ANALYSIS AND MODELING RESULTS APPENDIX D OTHER SPECIAL REPORTS 122 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 1 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn CHAPTER 1 – PROJECT OVERVIEW The Knudson Plat project is located 30106 SE 124th Street in the City of Auburn, Washington. The applicant is seeking to subdivide approximately 3.31 acres consisting of Parcel Number 0421059034, into 17 single-family residential lots (Project), with lot sizes ranging from approximately 4,832 to 7,687 square feet. The Project will provide frontage improvements on 124th Avenue SE. The Project is located within the Duwamish-Green River Watershed. 123 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 2 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn FIGURE 1 VICINITY MAP Type of City of Auburn permit requested: Preliminary Plat (Subdivision) Application - Auburn Reference No. PLT18-0006 Administrative Variance – Auburn Reference No. VAR18-0008 State Environmental Policy Act (SEPA) The applicant is applying for Auburn Preliminary Subdivision approval. The attached plans show the project boundaries, existing conditions, and proposed site development. The total parcel area is 144,180 square feet (3.310 acres). Site Address: 30106 124th Avenue SE Auburn, WA 98092 King County Tax Parcel Number: 042105-9034 There are no wetlands, or sensitive areas adjacent to or on the parcel, which is located in a residential area within the City of Auburn Selected Urban Growth area, and is bordered by single family residential units to the north, east and south and, 124th Avenue SE, a minor arterial classified roadway to the west. 124 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 3 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn The Applicant is seeking approval to subdivide 3.31 acres into 17 single-family residential lots (Project), with lot sizes ranging from 4,832 to 7,687 square feet. A new access road (an extension to SE 301st Place) with a cul-de-sac is proposed at the western portion of the Site. A 20-foot wide emergency vehicle access tract is proposed south of the proposed subdivision road to provide connectivity to 124th Ave SE. Legal Description: The west three-quarters of the west half of the south half of the north half of the southwest quarter of the southeast quarter of section 4, township 21 north, range 5 east, w. m., King County, Washington; except that portion thereof lying within 124th Avenue S.E.; and except the north 30 feet of the remainder; together with that property described as follows: beginning at the northwest corner of said west three-quarters, being more fully described in real estate contract to Fred and Sharon Thacker, recorded under King County recording no. 7807240564 (Thacker property); thence north 00°23'06" west 14.00 feet; thence south 89°56'18" east 371.35 feet; thence south 00°23'06" east 14.00 feet to the northerly line of said Thacker property; thence northwesterly along said northerly line to the point of beginning, as set forth in judgment quieting title in King County superior court cause no. 96-2-29421-7. situate in the City of Auburn, County of King, State of Washington. 125 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 4 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn CHAPTER 2 – EXISTING CONDITIONS SUMMARY The western half of the parcel is currently occupied by a single family residence and associated outbuildings. The eastern half of the site is undeveloped. The Site is primarily vegetated with mature trees and native vegetation. Access to the Site is from 124th Avenue SE via a gravel driveway. Site topography generally slopes down from the east toward the west direction with slopes ranging between 2 to 33 percent. Runoff from the site sheet flows in the same direction, toward 124th Avenue SE, with no signs of a defined channel. No known significant flows enter the site. The areas upstream of the project site consist of residential neighborhoods to the north, east and south, with their own drainage systems. Any runoff bypassing these systems is negligible Per King County iMap, the northwest portion of the Site is identified as an erosion hazard area (see below) with Alderwood gravelly sandy loam, 8 to 30 percent slopes (see Figure 2 for soils information). A Geotechnical Engineering Study has also been prepared by Earth Solutions NW LLC to address potential hazards, and mitigation actions, if necessary. The Geotechnical Engineering Study describes the surface soils as topsoil and fill underlain by dense to very dense silty sand and dense to very dense sandy silt, consistent with glacial till deposits. A Technical Memorandum by Soundview Consultants LLC was prepared to identify any potential impacts to Wetland, Fish, and Wildlife Habitat. No wetlands or streams are known to exist on or adjacent to the site. The site is not within potential landslide and steep slope hazard areas. 126 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 5 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn The site is not within seismic hazard area. The site is not within the Aquifer Recharge Area. The site is not within the 100-year floodplain. There are no superfund areas in the vicinity of the project. The existing house is on a private septic system and Type D well (Well ID: S_471955122103001). Both of these will need to be decommissioned per DOE and DOH standards, before any connection to City of Auburn water or sewer will be permitted. The well is within Groundwater Management Areas and Areas susceptible to ground contamination. There are no stormwater facilities or fuel tanks present on the site. The Soil Survey of King County Area, Washington, published by the United States Department of Agriculture, describes the near surface soils as Alderwood Series. More specifically AgC Alderwood Series, which is a “gravelly sandy loam”. DRAINAGE COMPLAINTS Complaint Number Complaint Type Problem Address Date Closed A 2004-0575 FCR MNM 30021 125th Court SE 8/24/2004 A 2004-0535 FCR MNM 30021 125th Court SE 8/25/2004 B 2004-0423 FCR MNM 12124 SE 303rd Court B 2004-0463 FCR MMG 12124 SE 303rd Court 6/7/2001 C 1994-0842 C DRNGREQ? 30515 124th Avenue SE 12/6/1994 Compliant Type: C - Action Request, Status: Active FCR - Facility Complaints – Residential, Status: Active Problem: DRNGREQ - Permit Requirements - Grading Permit MMG - Maintenance – General MNM - Needs Maintenance Drainage complaints as downloaded from King County iMap for the area around and downstream of the project site were reviewed. The drainage complaint list was screened to identify relevant complaints located along the conveyance system upstream and downstream of the site. Based on this review, the drainage complaints are unrelated to the conveyance system capacity or are maintenance / code enforcement issues. 127 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 6 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn FIGURE 2 SOIL MAP 128 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 7 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn CHAPTER 3 – OFFSITE ANALYSIS QUALITATIVE ANALYSIS Date of Field Inspection: September 11, 2018 Weather Conditions: Mostly cloudy, approximately 70 degrees Upstream Analysis In evaluating the upstream area, King County and City of Auburn topographic maps were reviewed. No known significant flows enter the site. The areas upstream of the project site consist of residential neighborhoods to the north, east and south, with their own drainage systems. Any runoff bypassing these systems is negligible. Stormwater collection system cannot be found on site. Run-off from the Site generally sheet flows in a westerly direction with no signs of a defined channel. This project will not produce backwater effects upstream of the site, and therefore the upstream area was excluded from this offsite analysis. Downstream Analysis The basin boundaries were verified, along with an examination of on-site and off-site drainage conditions. Groundcover, slopes, soil types, and other topographic features were also observed. As described in Chapter 2.5.10 of the COA Supplemental Manual Volume I, the study area shall extend downstream from the project site to the receiving water, or up to one-quarter mile, whichever is less. Drainage System Description The downstream analysis is further illustrated and detailed in the “OFFSITE ANALYSIS DOWNSTREAM MAP” and “OFF SITE ANALYSIS DRAINAGE SYSTEM TABLE”. The drainage area is located within the Lower Green River - East Drainage Basin and Duwamish – Green River Watershed. The drainage area was evaluated by reviewing available resources, and by conducting a field reconnaissance on September 11, 2018. Downstream Path Point “A”, a Type 1 catch basin with solid cover near the edge of the pavement, which conveys collected runoff from the northern portion of the Project Site. It is located offsite adjacent to the northwest property corner. From Point “A” to Point “B”, runoff continues southerly as pipe flow via an 18-inch CPP. Steady flow was observed. Point “B”, a Type 1 catch basin located near the edge of pavement. From Point “B” to Point “C”, runoff continues southerly as pipe flow via an 18-inch CPP. Steady flow was observed. Point “C”, an 18-inch CPP outlet located on the side of the roadside ditch. From Point “C” to Point “D”, runoff continues southerly as channel flow via a grass lined ditch. Steady flow was observed. 129 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 8 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Point “D”, a 12-inch concrete pipe (or an 18-inch ductile iron pipe) inlet at the lower end of the roadside ditch. From Point “D” to Point “E”, runoff continues southerly as pipe flow via a 12-inch concrete pipe (or an 18-inch ductile iron pipe). Steady flow was observed. Point “E”, a Type 1 catch basin located in the flow line of the curb and gutter. From Point “E” to Point “F”, runoff continues southerly as pipe flow via a 12-inch concrete pipe (or 18-inch PVC pipe). Steady flow was observed. Point “F”, a Type 1 catch basin with solid cover in the road pavement adjacent to the northeast curb return of SE 302nd Place. From Point “F” to Point “G”, runoff continues southerly as pipe flow via an 18-inch PVC pipe. Steady flow was observed. Point “G”, a Type 1 catch basin with solid cover in the road pavement adjacent to the southeast curb return of SE 302nd Place. From Point “G” to Point “H”, runoff continues southerly as pipe flow via an 18- inch PVC pipe. Steady flow was observed. Point “H”, a Type 2 catch basin with solid cover located in the landscape area (behind the sidewalk). From Point “H” to Point “I”, runoff continues southerly as pipe flow via an 18-inch PVC pipe. Steady flow was observed. Point “I”, a Type 2 catch basin with solid cover located in the sidewalk. From Point “I” to Point “J”, runoff continues southerly as pipe flow via a 24-inch storm drain pipe. Steady flow was observed. Point “J”, a Type 2 catch basin with solid cover located in the roundabout road pavement. From Point “J” to Point “K*”, runoff continues westerly as pipe flow via a 24-inch storm drain pipe. Steady flow was observed. Point “K*”, a rectangular shaped concrete detention facility with grated top located in the northwest quadrant of 124th Avenue SE/SE 304th Street intersection. From Point “K*” to Point “L*”, runoff continues westerly as pipe flow via a storm drain pipe (size unknown). Flow was not visible. Point “L*”, a Type 2 CBMH located on the west side of the detention facility, it is assumed to be equipped with a flow control structure. From Point “L*” to Point “M*”, runoff continues westerly as pipe flow via a storm drain pipe (size unknown). Flow was not visible. 130 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 9 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Point “M*”, a ‘CONTECH’ structure located on the west side of Point “L*”, it is assumed to be a water quality manhole. From Point “M*” to Point “N*”, runoff continues northwesterly as pipe flow via a storm drain pipe (size unknown). Flow was not visible. Point “N*”, a pipe outlet located northwest of the ‘CONTECH’ structure. From Point “N*” to the receiving water (wetland), runoff continues northwesterly as channel flow via grass lined ditch/swale. Flow was not visible. The receiving water (wetland) is greater than ¼ mile downstream of the Site. Review of Existing Records A review of the King County Water and Land Resources Division – Drainage Services Section Documented Drainage Complaints within one mile downstream from the Site revealed no recorded complaints within the last 10 years. Conclusion No significant drainage, erosion, or flooding problems were found during the downstream analysis or during review of existing records. No adverse drainage impacts are anticipated as a result of the proposed Project improvements as stormwater runoff peak flows from the project Site will not increase from the pre-developed conditions. Standard sediment and erosion control methods will be utilized during construction that will minimize soil erosion. This will include the use of a stabilized construction entrance, perimeter fencing, among other erosion control measures. A SWPPP will be prepared for this project and will be included at final engineering. 131 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 10 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn FIGURE 3 DOWNSTREAM MAP 132 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 11 of 51 Stormwater Site Plan Knudson Preliminary Plat City of Auburn OFF SITE ANALYSIS DRAINAGE SYSTEM TABLE Symbol Drainage Component Type, Size, and Name Description Slope Distance From site Discharge Existing Problems Potential Problems Observations See map Type: sheet flow, swale, channel, pipe, pond, flow control/water quality BMP Size: diameter, surface area Drainage basin, vegetation, cover, depth, type of sensitive area, volume % 1/4 mile = 1,320 feet 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 Type 1 CB with solid cover Near the edge of pavement –0’ None observed None Anticipated Steady flow was observed A-B Southerly pipe flow 18” Ø CPP 0.19% None Observed None Anticipated Steady flow was observed B Type 1 CB Near the edge of pavement –176’ None Observed None Anticipated Steady flow was observed B-C Southerly pipe flow 18” Ø CPP None Observed None Anticipated Steady flow was observed C 18” Ø CPP outlet ±270’ None Observed None Anticipated Steady flow was observed C-D Southerly channel flow Grass lined ditch 0.24% None Observed None Anticipated Steady flow was observed D 12” Ø conc. pipe inlet ±299’ None Observed None Anticipated Steady flow was observed D-E Southerly pipe flow 12” Ø concrete pipe 1.38% None Observed None Anticipated Steady flow was observed E Type 1 CB ±397’ None Observed None Anticipated CB located in flowline of curb & gutter E-F Southerly pipe flow 12” Ø concrete pipe 0.42% None Observed None Anticipated Steady flow was observed 133 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 12 of 51 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Symbol Drainage Component Type, Size, and Name Description Slope Distance From site Discharge Existing Problems Potential Problems Observations See map Type: sheet flow, swale, channel, pipe, pond, flow control/water quality BMP Size: diameter, surface area Drainage basin, vegetation, cover, depth, type of sensitive area, volume % 1/4 mile = 1,320 feet 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. F Type 1 CB with solid cover Runoff exits Site along the western property line. –430’ None observed None Anticipated No flow observed F-G Southerly sheet flow Lawn/ landscaping –8-10% None Observed None Anticipated No flow observed H Type 2 CB with solid cover East side of 7th St. S. –626’ None Observed None Anticipated No flow observed H-I Southerly sheet flow Mainly vertical curb and gutter –2-4% None Observed None Anticipated No flow observed I Type 2 CB with solid cover ±769’ None Observed None Anticipated No flow observed I-J Easterly pipe flow 8” Ø PVC pipe –2% None Observed None Anticipated No flow observed J Type 1 CB ±434’ None Observed None Anticipated CB located in sidewalk J-K Northerly pipe flow 12” Ø PE pipe –2-4% None Observed None Anticipated No flow observed K Type 1 CB ±494’ None Observed None Anticipated CB located in sidewalk K-L Northerly pipe flow 12” Ø PE pipe –2-4% None Observed None Anticipated Steady trickle flow observed L Type 1 CB ±549’ None Observed None Anticipated CB located in planter strip L-M Northerly pipe flow 12” Ø CPP –2-4% None Observed None Anticipated Steady trickle flow observed 134 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 13 of 51 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Symbol Drainage Component Type, Size, and Name Description Slope Distance From site Discharge Existing Problems Potential Problems Observations See map Type: sheet flow, swale, channel, pipe, pond, flow control/water quality BMP Size: diameter, surface area Drainage basin, vegetation, cover, depth, type of sensitive area, volume % 1/4 mile = 1,320 feet 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. M Natural discharge point Runoff exits Site along the western property line. –0’ None observed None Anticipated No flow observed M-N Westerly sheet flow Lawn/ landscaping –8-10% None Observed None Anticipated No flow observed N Flow Line East side of 7th St. S. –151’ None Observed None Anticipated No flow observed N-O Northerly channel flow Mainly vertical curb and gutter –2-4% None Observed None Anticipated No flow observed O Inlet CB ±426’ None Observed None Anticipated No flow observed Easterly pipe flow 8” Ø PVC pipe –2% None Observed None Anticipated No flow observed Type 1 CB ±434’ None Observed None Anticipated CB located in sidewalk Northerly pipe flow 12” Ø PE pipe –2-4% None Observed None Anticipated No flow observed E Type 1 CB ±494’ None Observed None Anticipated CB located in sidewalk E-F Northerly pipe flow 12” Ø PE pipe –2-4% None Observed None Anticipated Steady trickle flow observed F Type 1 CB ±549’ None Observed None Anticipated CB located in planter strip F-G Northerly pipe flow 12” Ø CPP –2-4% None Observed None Anticipated Steady trickle flow observed 135 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 14 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn PHOTOS Photo 1: Looking north – Location of Point “A” Photo 2: Looking south – Location of Point “A” 136 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 15 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Photo 3: Looking north – Between Point “A” and Point “B” Photo 4: Looking north – Location of Point “B” 137 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 16 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Photo 5: Looking south – Location of Point “B” Photo 6: Looking south toward the roadside ditch 138 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 17 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Photo 7: Looking west toward the gravel entrance Photo 8: Looking west toward the south portion of the Site 139 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 18 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Photo 9: Looking north – Location of “C” Photo 10: Looking north toward the lower end of the roadside ditch 140 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 19 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Photo 11: Looking south toward Point “E” Photo 12: Looking south toward Points “F” and “G” 141 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 20 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Photo 13: Looking north – Location of Point “J” Photo 14: Looking west toward the northeast quadrant of the roundabout 142 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 21 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Photo 15: Looking east toward the roundabout – Location of Point “ K” Photo 16: Looking northwest toward Points “L” and “M” 143 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 22 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Photo 17: Point “L” – a King County drain manhole Photo 18: Location of “M” – a ‘CONTECH’ structure 144 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 23 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Photo 19: Looking northwest toward flow channel to the wetland Photo 20: Looking west toward SE 304th Street 145 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 24 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Photo 21: Looking east toward the King County detention facility Photo 22: Looking north toward 124th Avenue SE 146 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 25 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn FIGURE 4 IMAP CONTOUR MAP 147 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 26 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn CHAPTER 4 – PERMANENT STORMWATER CONTROL PLAN The site is contained within one TDA. This project adds more than 5,000 s.f. of pollution-generating impervious surface (PGIS); therefore, the Project shall adhere to Minimum Requirement #6: Runoff Treatment. The increase in the 100-year flow frequency within this TDA is 1.52 cfs; therefore, the Project shall adhere to Minimum Requirement #7: Flow Control. A detention pond facility will be located Tract ‘E’, and will provide flow control and water quality treatment. See Sections 2 and 3 below for predeveloped and developed landcover and hydrology. 148 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 27 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn THRESHOLD DISCHARGE AREAS Threshold Discharge Area (TDA) Table Basin: West TDA Name: West TDA Number: 1 Date: 11.8.18 Description On-site Off-site Total Existing Conditions Total Project Area (ft2) 144,180 5,737 149,917 Existing hard surface (ft2) 9,750 1,797 11,547 Existing Native Vegetation area (ft2) 134,430 3,940 138,370 Existing lawn/landscaped area (ft2) Proposed Conditions Total Project Area (ft2) 144,180 5,737 149,917 Amount of new hard surface (ft2) 86,811 6,894 93,705 Amount of new pollution generating hard surface (PGHS) (ft2) 35,628 3,870 39,498 Amount of replaced hard surface (ft2) 9,750 1,797 11,547 Amount of replaced PGHS (ft2) 4,363 1,702 6,065 Amount of new + replaced hard surface (ft2) 96,561 8,691 105,252 Amount of new + replaced PGHS (ft2) 36,091 8,596 44,687 Amount of existing hard surfaces converted to Vegetation (ft2) 0 0 0 Amount of Land Disturbed (ft2) 144,180 5,737 149,917 Amount of native vegetation converted to lawn/landscaped area (ft2) 6,000 0 6,000 Amount of native vegetation converted to pasture (ft2) 42,751 0 42,751 Existing native vegetation area to remain (ft2) 0 0 0 Existing hard surface to remain unaltered (ft2) 0 0 0 Value of proposed improvements ($) 725,000 26,235 751,235 Assessed value of existing site improvement ($) 284,000 8,000 292,000 Amount to be graded/filled (Cubic Feet) 239,787 filled 675 filled 240,462 filled 149 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 28 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn PRE-DEVELOPED SITE HYDROLOGY For the purpose of these calculations the predeveloped site condition was modeled as “C, Forest, Mod”. Predeveloped Condition Input DEVELOPED SITE HYDROLOGY Project Summary Development activity will involve site grading to accommodate roadways and single-family residential lots. Catch basins will intercept stormwater runoff and route flows via storm pipe towards the onsite stormwater facility, located in the northwest corner of the parcel. Roof runoff will be collected and tight-lined to the pipe network. 150 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 29 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn The storrmwater facility will be designed to provide detention and water quality treatment. Flows will exit the detention facility via a release structure designed to mimic predeveloped release rates. Flows will enter the City’s storm drainage system. On-Site Stormwater Management System – Minimum Requirement #5 The project meets the thresholds triggering Minimum Requirements #1 through #9 and must meet the requirements of Table 2.5.1 for Onsite Stormwater Management. The project is new development inside the UGA on a parcel less than 5 acres and therefore has the option of meeting the Low Impact Development Performance Standard or utilizing the LID list approach. The project will utilize the list approach. See Chapter 4 for flow control BMP summary, feasibility and description. Water Quality System – Minimum Requirement #6 The project meets the thresholds triggering Minimum Requirement #6 and will provide water quality treatment within the combined detention/WQ pond to accommodate water quality requirements. The pond has been sized as prescribed in the manual using discharge rates as calculated with WWHM2012. Based on the WWHM2012 analysis, the required water quality treatment storage volume is 13,146 cubic feet. The combination detention/WQ pond provides a water quality treatment storage volume of 24,600 cubic feet. Flow Control System – Minimum Requirement #7 A detention pond located in Tract E will accommodate flow control requirements. A continuous simulation model, WWHM2012, version 4.2.15 was used to analyze the pre- and post- developed runoff rates. The soil type is modeled as hydrologic soil group C for the Alderwood SCS classification as shown in Figure 2. Results of the WWHM2012 analysis are included in Appendix C. A stormwater detention pond will provide flow control for Project runoff. The detention pond required 6-feet of live storage depth. The soil types are unchanged from pre developed conditions. The lot impervious area was assumed to be 65% of the total lot area. WWHM2012 Input is below. 151 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 30 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Developed Condition Input 152 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 31 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Bypass Input 153 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 32 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn The required detention volume, as determined by WWHM 65,340 cf. The detention pond as designed will provide 69,141 cf of live storage. Conventional Conveyance System Analysis and Design The on-site conveyance system consists of a closed pipe system that connects area drains to the detention facility. The runoff is then conveyed via a 12-inch pipe towards 124th Avenue SE. A backwater analysis of the onsite system will be conducted at final engineering. Since the project is reducing the rate of runoff from the site, and no problems were observed during the downstream analysis, the off-site conveyance is considered to have sufficient capacity for the proposed project. 154 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 33 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn FIGURE 5 PRE-DEVELOPED AREA MAP 155 of 189 COPYRIGHT , D.R. STRONG CONSULTING ENGINEERS INC.c GRAPHIC SCALE 0 25 50 75 1 INCH = 50 FT. 156 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 34 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn FIGURE 6 DEVELOPED AREA MAP 157 of 189 COPYRIGHT , D.R. STRONG CONSULTING ENGINEERS INC.c GRAPHIC SCALE 0 25 50 75 1 INCH = 50 FT. 158 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 35 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn CHAPTER 5 – DISCUSSION OF MINIMUM REQUIREMENTS Per Figure 2.4.1 of the Manual, the Project must comply with Minimum Requirements #1 through #10. The following is a summary of how each Minimum Requirement is met. 159 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 36 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn MINIMUM REQUIREMENT #1: PREPARATION OF STORMWATER SITE PLANS This report shall serve as compliance with MR 1. MINIMUM REQUIREMENT #2: CONSTRUCTION STORMWATER POLLUTION PREVENTION (SWPP) A complete Construction Stormwater Pollution Prevention Plan will be submitted provided at the time of final engineering. Each of the 13 construction SWPP elements will be considered and discussed below. Element 1: Preserve Vegetation/ Mark clearing limits: Vegetation shall be preserved (BMP C101) by restricting construction activities outside of the clearing limits shown. Clearing limits shall be marked with a high visibility plastic fence (BMP C103). Element 2: Establish construction access: A stabilized construction entrance (BMP C120) will be provided at the location of proposed access road to the Site. Element 3: Control flow rates: Flow rates shall be controlled by a silt fence (BMP C223) at the downslope edge of the clearing limits and a vegetated strip (BMP C234) between the filter fence and the west property line. Element 4: Install sediment controls: Sediment shall be controlled by a silt fence (BMP C223) at the downslope edge of the clearing limits and a vegetated strip (BMP C234) between the filter fence and the west property line. Element 5: Stabilize soils: Unworked soils shall be stabilized with mulching (BMP C121) and/ or dust control (BMP C140) measures. Excavated material will be loaded directly into a dump truck staged on site and therefore, no soil stockpiles are proposed on this site. Final site stabilization will be achieved through compost-amending (BMP T5.13). Element 6: Protect slopes: Slopes will be protected with compost-amended soils (BMP T5.13) and permanent seeding and planting (BMP C120). Element 7: Protect drain inlets: Drain inlets will be protected with a catch basin filter insert (BMP C220) Element 8: Stabilize channels and outlets: No channels or outfalls affected by this project. Element 9: Control pollutants: Contractor shall implement concrete handling (BMP C151) and material storage, delivery, and containment (BMP C153) measures as well as other appropriate pollution source control measures in areas of: construction equipment maintenance or fueling; handling or storage of waste materials, construction debris, fertilizers, and chemicals; and other activities that may contribute pollutants to stormwater. The following specific requirements apply: 160 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 37 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn A) Cover, containment, and protection from vandalism shall be provided for all chemicals, liquid products, petroleum products, and other materials that have potential to pose a threat to human health or the environment. B) On-site fueling tanks shall include secondary containment. C) Maintenance, fueling and repair of heavy equipment and vehicles shall be conducted using spill prevention and control measures consistent with Volume IV, Chapters 2 and 3. D) Contaminated surfaces shall be cleaned immediately following any spill incident. E) Application of fertilizers and pesticides shall be conducted in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Manufacturers' label requirements for application rates and procedures shall be followed. F) BMP's shall be used to prevent contamination of stormwater runoff by pH modifying sources. These sources include, but are not limited to, bulk cement, cement kiln dust, fly ash, new concrete washing approved treatment, curing waters, waste streams generated from concrete grinding and sawing, exposed aggregate processes, dewatering concrete vaults, concrete pumping and mixer washout/ water. G) Concrete truck chutes, pumps, and internals shall be washed out only into formed areas awaiting installation of concrete. Unused concrete remaining in the truck and pump shall be returned to the originating batch plant for recycling. Washdown from concrete hand tools and work areas shall not drain directly to natural or constructed stormwater conveyances. When no formed areas are available, washwater and leftover product shall be contained in a lined container and disposed of in a manner that does not violate groundwater or surface water quality standards. H) Where feasible, and not in conflict with International Fire Code, store potential stormwater pollutant materials inside a building or under a cover and/or containment. Liquid and applicable solid materials must be stored in containers suitable for the contents and inspected for corrosion, structural failure, tight fitting lids, leaks and overfills. Store materials in areas sloping away from storm drainage systems or surface waters. Sweep and clean the job site regularly to prevent buildup of contaminating materials. Promptly clean up solid and liquid pollutant leaks and spills and dispose of in a manner consistent with and all other federal, state, and local regulations in order to prevent stormwater pollution. Element 10: Control de-watering: There are no dewatering operations planned for this project. 161 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 38 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Element 11: Maintain BMPs: BMP's shall be inspected and maintained by the contractor during construction and removed within 30 days after the City determines that the site is stabilized, provided that temporary BMP's may be removed when they are no longer needed. Element 12: Manage the project: This plan shall be fully implemented at all times and modified whenever there is a change in design, construction, operation, or maintenance at the construction site that has or could have a significant effect on the discharge of pollutants to waters of the State. Element 13: Protect Low Impact Development (LID) BMPs: Permittees must protect all bioretention and rain garden facilities from sedimentation through installation and maintenance of erosion and sediment control BMPS on portions of the site that drain into the bioretention and/or rain garden facilities. Restore the facilities to their fully functioning condition if they accumulate sediment during construction. Restoring the facility must include removal of sediment and any sediment-laden bioretention/rain garden soils, and replacing the removed soils with soils meeting the design specification. Permittees must maintain the infiltration capabilities of bioretention and rain garden facilities by protecting against compaction by construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. Permittees must control erosion and avoid introducing sediment from surrounding land uses onto permeable pavements. Do not allow muddy construction equipment on the base material or pavement. Do not allow sediment- laden runoff onto permeable pavements. Permittees must clean permeable pavements fouled with sediments or no longer passing an initial infiltration test using local stormwater manual methodology or the manufacturer's procedures. Permittees must keep all heavy equipment off existing soils under lid facilities that have been excavated to final grade to retain the infiltration rate of the soils. MINIMUM REQUIREMENT #3: SOURCE CONTROL OF POLLUTION Not applicable for residential development. MIMIMUM REQUIREMENT #4: PRESERVATION OF NATURAL DRAINAGE SYSTEMS AND OUTFALLS Natural drainage patterns shall be maintained for the site. The Developed runoff from the site will be collected in the combined detention/WQ pond before discharge into the existing public drainage system in 124th Avenue SE. 162 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 39 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn There should be little if any significant adverse impact to downstream receiving waters and down gradient properties. MINIMUM REQUIREMENT #5: ON-SITE STORMWATER MANAGEMENT The Project triggers MR’s #1 – #10 and is therefore required to evaluate the List #2 BMP’s in accordance with the City of Auburn Surface Water Management Manual (SWMM). 163 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 40 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn Lawn and Landscaped Areas: • The Project will implement BMP T5.13 Post-Construction Soil Quality and Depth in accordance with Volume V Chapter 5 of the 2012 DOE Stormwater Manual, as Amended in 2014. Within the limits of Site disturbance, duff and topsoil (where available) will be retained in an undisturbed state and stockpiled for later use to stabilize and amend soils throughout the Site. Soil amendment will be accomplished by tilling three inches of compost eight inches into disturbed soil in the areas of planting beds or by tilling two inches of compost eight inches into disturbed soil in 164 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 41 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn the areas of lawn turf. Two to four inches of arborist wood chip, coarse bark mulch, or compost mulch shall be added to planting beds after final planting. Roofs: • BMP T5.30 – Full dispersion: Infeasibility Criteria: a. The minimum 100’ native vegetated flowpath cannot be provided due to lot sizes nor can the required open space be preserved. • BMP T7.30 – Bioretention Cells, Swales and Planter Boxes: Infeasibility Criteria: a. Lot sizes will not allow for structure and/or property line setbacks to be met b. Homes will have crawl spaces c. All roadway grades are greater than 8%. d. Glacial Till (impervious layer) throughout the site. • BMP T5.10B – Downspout Dispersion Systems: Infeasibility Criteria: a. Dispersion systems are not feasible because the minimum 25’ vegetated flowpath cannot be provided due to lot sizes. • BMP T5.10C – Perforated Stub Out Connections: a. Perforated stub out connections will be utilized for individual lot roof areas prior to entering the site conveyance system. Other Hard Surfaces: • BMP T5.30 – Full dispersion: Infeasibility Criteria: a. The minimum 100’ native vegetated flowpath cannot be provided due to lot sizes nor can the required open space be preserved. • BMP T5.15 – Permeable Pavement (private residential driveways) Infeasibility Criteria: a. Pursuant to the Geotechnical Engineering Study, the site is underlain by cemented glacial drift deposits. b. Given the glacial drift deposits, the soil would not meet treatment requirements. • BMP T7.30 – Bioretention Cells, Swales and Planter Boxes: Infeasibility Criteria: a. Lot sizes will not allow for structure and/or property line setbacks to be met b. Homes will have crawl spaces c. All roadway grades are greater than 8%. d. Glacial Till (impervious layer) throughout the site. • BMP T5.11 – Concentrated Flow Dispersion: Infeasibility Criteria: a. 50’ vegetated flow path cannot be met due to lot sizes. 165 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 42 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn MINIMUM REQUIREMENT #6: RUNOFF TREATMENT A combined detention/WQ pond in Tract E will treat runoff flows. The project meets the thresholds triggering Minimum Requirement #6 and will provide water quality treatment within the combined detention/WQ pond to accommodate water quality requirements. The pond has been sized as prescribed in the manual using discharge rates as calculated with WWHM2012. Based on the WWHM2012 analysis, the required water quality treatment storage volume is 13,146 cubic feet. The combination detention/WQ pond provides a water quality treatment storage volume of 24,600 cubic feet MINIMUM REQUIREMENT #7: FLOW CONTROL A combined detention/WQ pond located in Tract E will accommodate flow control requirements. A continuous simulation model, WWHM 2012, version 4.2.15 was used to analyze the pre- and post- developed runoff rates. The soil type is modeled as hydrologic soil group C for the Alderwood SCS classification as shown in Figure 2. Results of the WWHM2012 analysis are included in Appendix C. A stormwater detention pond will provide flow control for Project runoff. The detention pond required 6-feet of live storage depth. Performance Standards The Washington State Department of Ecology’s flow control standard is based on flow duration. The duration criteria are: 1. If the post-development flow duration values exceed any of the predevelopment flow levels between 50% and 100% of the two-year predevelopment peak flow values (100 Percent Threshold) then the flow control standard requirement has not been met. 2. If the post-development flow duration values exceed any of the predevelopment flow levels between 100% of the two-year and 100% of the 50-year predevelopment peak flow values more than 10 percent of the time (110 Percent Threshold) then the flow control standard has not been met. 3. If more than 50 percent of the flow duration levels exceed the 100 percent threshold then the flow control standard has not been met. The default pass/fail threshold is 110%. The detention facility has been designed to meet the requirements of Chapter 2 of Volume 1 of the 2014 DOE Stormwater Manual. The facility will match the DOE’s flow control standard. 166 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 43 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn MINIMUM REQUIREMENT #8: WETLANDS PROTECTION The project discharges to the conveyance system in 124th Avenue SE before entering an open channel/ravine which eventually leads to a wetland approximately 2,200 lf downstream of the Site. This may be considered an indirect discharge to the wetland, therefore the standard requirement of compliance with Guide Sheets 1 through 3 was analyzed. Guide Sheets 1 and 2 discuss use of wetlands as treatment or flow control facilities which this project is not proposing to do, rendering both non-applicable. Guide Sheet 3A discusses protection of wetlands; the project significantly upstream of the wetland in question and is not proposing any impacts to the buffer or actual wetland. Guide Sheet 3B discusses changes in water flows and the affect this can have on wetland areas. As stated, the project is 2200 lf upstream and site runoff naturally attenuates in the open channel/ravine before reaching the wetland. Therefore, it is our determination that Guide Sheet 3b should not apply, therefore making MR 8 not applicable to this project. MINIMUM REQUIREMENT #9: OPERATION AND MAINTENANCE An Operation and Maintenance excerpt from the DOE Drainage Manual will be included in Appendix A at FAC Submittal. MINIMUM REQUIREMENT #10: OFF-SITE ANALYSIS AND MITIGATION See Chapter 3 in this report. . 167 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 44 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn APPENDICES 168 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 45 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn APPENDIX A MAINTENANCE AND OPERATIONS MANUAL Not included in Hearing Examiner packet. 169 of 189 2019 D. R. STRONG Consulting Engineers Inc. Page 46 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn APPENDIX B SWPPP Not included in Hearing Examiner packet. 170 of 189 D.R. STRONG Consulting Engineers, Inc.Knudson Preliminary Plat Stormwater Pollution Prevention Plan Page A-1 May 5, 2019 Appendix A BMP Details Not included in Hearing Examiner packet. 171 of 189 D.R. STRONG Consulting Engineers, Inc.Knudson Preliminary Plat Stormwater Pollution Prevention Plan Page B-1 May 5, 2019 Appendix B Correspondence 172 of 189 D.R. STRONG Consulting Engineers, Inc. Knudson Preliminary Plat Stormwater Pollution Prevention Plan Page C-1 May 5, 2019 Appendix C Site Inspection Form The results of each inspection shall be summarized in an inspection report or checklist that is entered into or attached to the site log book. It is suggested that the inspection report or checklist be included in this appendix to keep monitoring and inspection information in one document, but this is optional. However, it is mandatory that this SWPPP and the site inspection forms be kept onsite at all times during construction, and that inspections be performed and documented as outlined below. At a minimum, each inspection report or checklist shall include: Inspection date/times Weather information: general conditions during inspection, approximate amount of precipitation since the last inspection, and approximate amount of precipitation within the last 24 hours. A summary or list of all BMPs that have been implemented, including observations of all erosion/sediment control structures or practices. The following shall be noted: locations of BMPs inspected, locations of BMPs that need maintenance, The reason maintenance is needed, locations of BMPs that failed to operate as designed or intended, and locations where additional or different BMPs are needed, and the reason(s) why A description of stormwater discharged from the site. The presence of suspended sediment, turbid water, discoloration, and/or oil sheen shall be noted, as applicable. A description of any water quality monitoring performed during inspection, and the results of that monitoring. General comments and notes, including a brief description of any BMP repairs, maintenance or installations made as a result of the inspection. A statement that, in the judgment of the person conducting the site inspection, the site is either in compliance or out of compliance with the terms and conditions of the SWPPP and the NPDES permit. If the site inspection indicates that the site is out of compliance, the inspection report shall include a summary of the remedial actions required to bring the site back into compliance, as well as a schedule of implementation. 173 of 189 D.R. STRONG Consulting Engineers, Inc. Knudson Preliminary Plat Stormwater Pollution Prevention Plan Page C-2 May 5, 2019 Name, title, and signature of person conducting the site inspection; and the following statement: “I certify under penalty of law that this report is true, accurate, and complete, to the best of my knowledge and belief”. When the site inspection indicates that the site is not in compliance with any terms and conditions of the NPDES permit, the Permittee shall take immediate action(s) to: stop, contain, and clean up the unauthorized discharges, or otherwise stop the noncompliance; correct the problem(s); implement appropriate Best Management Practices (BMPs), and/or conduct maintenance of existing BMPs; and achieve compliance with all applicable standards and permit conditions. In addition, if the noncompliance causes a threat to human health or the environment, the Permittee shall comply with the Noncompliance Notification requirements in Special Condition S5.F of the permit. 174 of 189 Construction Stormwater Site Inspection Form D.R. STRONG Consulting Engineers, Inc.Knudson Preliminary Plat Stormwater Pollution Prevention Plan Page C-3 May 5, 2019 Project Name Permit #: Date: Time: Name of Certified Erosion Sediment Control Lead (CESCL) or qualified inspector if less than one acre Print Name: Approximate rainfall amount since the last inspection (in inches): Approximate rainfall amount in the last 24 hours (in inches): Current Weather Clear Cloudy Mist Rain Wind Fog A.Type of inspection:Weekly Post Storm Event Other B. Phase of Active Construction (check all that apply): Pre Construction/installation of erosion/sediment controls Clearing/Demo/Grading Infrastructure/storm/roads Concrete pours Vertical Construction/buildings Utilities Offsite improvements Site temporary stabilized Final stabilization C. Questions: 1. Were all areas of construction and discharge points inspected?Yes No 2. Did you observe the presence of suspended sediment, turbidity, discoloration, or oil sheen Yes No 3.Was a water quality sample taken during inspection? (refer to permit conditions S4 & S5)Yes No 4. Was there a turbid discharge 250 NTU or greater, or Transparency 6 cm or less?*Yes No 5. If yes to #4 was it reported to Ecology?Yes No 6. Is pH sampling required? pH range required is 6.5 to 8.5.Yes No If answering yes to a discharge, describe the event. Include when, where, and why it happened; what action was taken, and when. *If answering yes to # 4 record NTU/Transparency with continual sampling daily until turbidity is 25 NTU or less/ transparency is 33 cm or greater. Sampling Results: Date: Parameter Method (circle one) Result Other/Note NTU cm pH Turbidity tube, meter, laboratory pH Paper, kit, meter 175 of 189 Construction Stormwater Site Inspection Form D.R. STRONG Consulting Engineers, Inc.Knudson Preliminary Plat Stormwater Pollution Prevention Plan Page C-4 May 5, 2019 D. Check the observed status of all items. Provide “Action Required “details and dates. Element # Inspection BMPs Inspected BMP needs maintenance BMP failed Action required (describe in section F) yes no n/a 1 Clearing Limits Before beginning land disturbing activities are all clearing limits, natural resource areas (streams, wetlands, buffers, trees) protected with barriers or similar BMPs? (high visibility recommended) 2 Construction Access Construction access is stabilized with quarry spalls or equivalent BMP to prevent sediment from being tracked onto roads? Sediment tracked onto the road way was cleaned thoroughly at the end of the day or more frequent as necessary. 3 Control Flow Rates Are flow control measures installed to control stormwater volumes and velocity during construction and do they protect downstream properties and waterways from erosion? If permanent infiltration ponds are used for flow control during construction, are they protected from siltation? 4 Sediment Controls All perimeter sediment controls (e.g. silt fence, wattles, compost socks, berms, etc.) installed, and maintained in accordance with the Stormwater Pollution Prevention Plan (SWPPP). Sediment control BMPs (sediment ponds, traps, filters etc.) have been constructed and functional as the first step of grading. Stormwater runoff from disturbed areas is directed to sediment removal BMP. 5 Stabilize Soils Have exposed un-worked soils been stabilized with effective BMP to prevent erosion and sediment deposition? Are stockpiles stabilized from erosion, protected with sediment trapping measures and located away from drain inlet, waterways, and drainage channels? Have soils been stabilized at the end of the shift, before a holiday or weekend if needed based on the weather forecast? 176 of 189 Construction Stormwater Site Inspection Form D.R. STRONG Consulting Engineers, Inc.Knudson Preliminary Plat Stormwater Pollution Prevention Plan Page C-5 May 5, 2019 Element # Inspection BMPs Inspected BMP needs maintenance BMP failed Action required (describe in section F) yes no n/a 6 Protect Slopes Has stormwater and ground water been diverted away from slopes and disturbed areas with interceptor dikes, pipes and or swales? Is off-site storm water managed separately from stormwater generated on the site? Is excavated material placed on uphill side of trenches consistent with safety and space considerations? Have check dams been placed at regular intervals within constructed channels that are cut down a slope? 7 Drain Inlets Storm drain inlets made operable during construction are protected. Are existing storm drains within the influence of the project protected? 8 Stabilize Channel and Outlets Have all on-site conveyance channels been designed, constructed and stabilized to prevent erosion from expected peak flows? Is stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes and downstream conveyance systems? 9 Control Pollutants Are waste materials and demolition debris handled and disposed of to prevent contamination of stormwater? Has cover been provided for all chemicals, liquid products, petroleum products, and other material? Has secondary containment been provided capable of containing 110% of the volume? Were contaminated surfaces cleaned immediately after a spill incident? Were BMPs used to prevent contamination of stormwater by a pH modifying sources? Wheel wash wastewater is handled and disposed of properly. 10 Control Dewatering Concrete washout in designated areas. No washout or excess concrete on the ground. Dewatering has been done to an approved source and in compliance with the SWPPP. Were there any clean non turbid dewatering discharges? 177 of 189 Construction Stormwater Site Inspection Form D.R. STRONG Consulting Engineers, Inc.Knudson Preliminary Plat Stormwater Pollution Prevention Plan Page C-6 May 5, 2019 Element # Inspection BMPs Inspected BMP needs maintenance BMP failed Action required (describe in section F) yes no n/a 11 Maintain BMP Are all temporary and permanent erosion and sediment control BMPs maintained to perform as intended? 12 Manage the Project Has the project been phased to the maximum degree practicable? Has regular inspection, monitoring and maintenance been performed as required by the permit? Has the SWPPP been updated, implemented and records maintained? E. Check all areas that have been inspected. All in place BMPs All discharge locations All concrete wash out areas All construction entrances/exits All disturbed soils All material storage areas All equipment storage areas F. Elements checked “Action Required” (section D) describe corrective action to be taken. List the element number; be specific on location and work needed. Document, initial, and date when the corrective action has been completed and inspected. Element # Description and Location Action Required Completion Date Initials Attach additional page if needed Sign the following certification: “I certify that this report is true, accurate, and complete, to the best of my knowledge and belief” Inspected by: Print Signature Title/Qualification of Inspector Date 178 of 189 2019 D. R. STRONG Consulting Engineers Inc.Page 47 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn APPENDIX C HYDRAULIC/HYDROLOGIC ANALYSIS AND MODELING RESULTS Not included in Hearing Examiner packet. 179 of 189 2019 D. R. STRONG Consulting Engineers Inc.Page 48 of 48 Stormwater Site Plan Knudson Preliminary Plat City of Auburn APPENDIX D OTHER SPECIAL REPORTS Reports included as other exhibits in Hearing Examiner packet (e.g. Geotech Report). 180 of 189 ____________________________________________________________________________ School Walkway Analysis for KNUDSON PRELIMINARY PLAT 30106 124th Avenue SE Auburn, WA 98092 ____________________________________________________________________________ DRS Project No. 18042 City of Auburn File No. PRE18-0032 Owner/Applicant Harbour Homes, LLC 400 N. 34th St., Suite 300 Seattle, WA 98103 Report Prepared by D. R. STRONG Consulting Engineers, Inc. 620 7th Avenue Kirkland WA 98033 (425) 827-3063 Report Issue Date November 9, 2018 Exhibit 10 School Walkway Analysis 181 of 189 ________________________________________________________________________________________________________ 2018 D. R. STRONG Consulting Engineers Inc 1 Knudson Preliminary Plat School Walkway Analysis Auburn, Washington SCHOOL WALKWAY ANALYSIS Elementary School: Arthur Jacobsen Elementary Students will attend Arthur Jacobson Elementary located at 29205 132 nd Avenue SE. This is not within the safe walking distance from the proposed plat, so the students will instead walk to the nearest bus stop located at the intersection of 124 th Avenue SE and SE 302nd Place. Students will head south via the proposed emergency vehicle access tract to the sidewalk on the north side of SE 302nd Pl. They will continue west from there to the bus stop via the existing sidewalk on SE 302nd Pl. The bus stop information was found using the E-Link School/Transportation Information Portal for the Auburn School District. A picture of this information from the E-Link Portal along with pictures from along the walkway path can be found below. E-Link Portal Information for Elementary School Looking West Along SE 302nd Place 182 of 189 ________________________________________________________________________________________________________ 2018 D. R. STRONG Consulting Engineers Inc 2 Knudson Preliminary Plat School Walkway Analysis Auburn, Washington Middle School: Rainier Middle School High School: Auburn Mountainview High School According to the City of Auburn E-Link portal, students will ride the bus from this plat to both Rainier Middle School and Auburn Mountainview High School. Rainier Middle is located at 30620 116th Ave. SE and Auburn Mountianview High is located at 28900 124th Ave SE. The bus stop nearest to this proposed plat stop for both the middle and upper school is located also at the corner of 124 th Ave. SE and SE 302nd Pl, the same location as the elementary school bus stop. All students will use the same safe walking route and the same bus stop. The photos below show the information provided by the E-Link portal indicating the location of the nearest bus stop for the high school and middle schools. E-Link Portal Information for Middle School E-Link Portal Information for High School 183 of 189 Engineers Surveyors Planners 620 7th Ave. Kirkland, WA 98033-5565 Phone: (425) 827-3063 Fax: (425) 827-2423 Toll Free: (800) 962-1402 www.drstrong.com August 13, 2019 DRS Project No. 18042 Alexandria Teague City of Auburn 25 West Main Street Auburn, WA 98001 Re: Knudson Subdivision, Plat Modification Request Dear Ms. Teague, This letter is provided to request and support a variance request for this project. The variance meets the threshold for Administrative approval. Description of Plat Modification Four of 17 proposed single family lots do not meet the minimum lot width standard required for platted corner lots within the R-5 zone. According to Title 17.14.090(D) of the City Code, corner lots designated for residential uses shall be platted at least five feet wider than required by the zoning ordinance. Lots numbered 2, 5, 7, and 13 do not meet the minimum lot width requirement for corner lots. In lieu of not meeting the minimum lot width requirement, these lots will be required to have an additional 5 feet of building setback for a total building setback distance of 10 feet from the property line located along the access tract. Findings of Fact, ACC 17.18.030 A. Such modification is necessary because of special circumstances related to the size, shape, topography, location or surroundings of the subject property, to provide the owner with development rights and privileges permitted to other properties in the vicinity and in the zoning district in which the subject property is located; The special circumstances are a result of the property’s spatial proximity and topography as it relates to meeting City code for emergency vehicle access requirements B. That, because of such special circumstances, the development of the property in strict conformity with the provisions of this title will not allow a reasonable and harmonious use of the property; Adhering to the increased width would reduce the number of proposed lots below base density for the parcel area. C. That the modification, if granted, will not alter the character of the neighborhood, or be detrimental to surrounding properties in which the property is located; Exhibit 11 Plat Modification Request Letter 184 of 189 Alexandria Teague August 13, 2019 Page 2 of 2 The reduction in widths and area are negligible relative to the required minimums. Therefore, there should be no adverse impact to the character of the neighborhood or surrounding properties. D. Such modification will not be materially detrimental to the implementation of the policies and objectives of the comprehensive land use, transportation and utility comprehensive plans of the city; The intent to provide a larger setback will be adhered to, therefore, the modification will not be materially detrimental to city policies. E. Literal interpretation of the provisions of this title would deprive the applicant of rights commonly enjoyed by other properties in the same zoning district; Literal interpretation would reduce the number of proposed lots below base density for the parcel area. F. The approval of the modification will be consistent with the purpose of this title; Approval would be consistent with the purpose as specified in ACC 17.18.005 G. The modification cannot lessen the requirements of the zoning ordinance. Any such modification must be processed as a variance pursuant to ACC 18.70.010. The modification does not lessen the requirements of the zoning ordinance. Thank you for your consideration in this matter. If you have any questions or concerns, please do not hesitate to contact me. Sincerely yours, D. R. STRONG Consulting Engineers Inc. Maher A. Joudi P.E. Principal, General Manager MAJ \\kirklandacad\R-docsdwg\2018\0\18042\Correspondence\Letters\out\L190806_PlatModification18042.doc 185 of 189 Engineers Surveyors Planners 620 7th Ave Kirkland, WA 98033-5565 Phone: (425) 827-3063 Fax: (425) 827-2423 Toll Free: (800) 962-1402 www.drstrong.com June 19, 2019 Project No. 18042 Shannon Howard City of Auburn Department of Community Development 25 West Main Street Auburn WA 98001 Re: Knudson Preliminary Plat PLT18-0006 – Deviation Request Dear Mr. Howard, This letter is provided to request and support a deviation request to increase the maximum road grades, throughout the project from 8% to 10%. Design Standards Section 10.02.4 Vertical Grades “Vertical Grades, the amount of slope of a street in the direction of travel, is limited to a maximum of 6% for Arterials and 8% for all other streets. All street sections shall maintain a minimum 0.5% vertical grade. Vertical grades may be increased up to 10% for non-arterials upon approval of the City Engineer.” Description of Required Deviation The project is proposing a maximum road grade along SE 301st Place and the emergency vehicle access road of 10%. Justification of Required Deviation Southeast 301st Place stubs to the site’s eastern property line in order to provide for future extension and development; the project is in fact, proposing to extend the roadway and terminate in a cul de sac. Additionally, due to the number of homes serviced from a single access point, an emergency vehicle connection to 124th is required. Given the connecting road grade at SE 301st (2.89%) and the vertical relief between the connection point and 124th (44 vertical feet over 465 feet), making the connections requires the increased slope. Pursuant to Section 1.04.1 of the 2018 City of Auburn Engineering Design Standards, an engineering design deviation will be approved when compelling supporting justification clearly demonstrates that the proposed deviation will meet or exceed the corresponding City standard for the following applicable criteria (justification provided after each criteria): A. The functional intent of the design element. The intent of the design element is to provide safe access with adequate sight distance to adjacent properties. The vertical curves proposed meet City standards for sight distance and the increase in grade does not affect the adjacent properties ability to access the roadway. B. Safety factors associated with the design element. Sight distance requirements have been met. C. Operational concerns associated with the design element. The increased slope should not affect the operational use of the roadways. D. Maintenance concerns associated with the design element. Maintenance is not affected by the deviation request. Exhibit 12 Engineering Deviation Request & COA Recommend Approval Letter 186 of 189 Shannon Howard June 21, 2019 Page 2 of 2 E. Liability concerns associated with the design element. An increase in road slope may result in higher speeds. However the roadway is a dead end with high density of driveways therefore, speeds are expected to be low. Sight distance requirements, as adjusted for the increased road slope, are met for the design. F. The capacity and/or efficiency of the design element. The capacity and/or efficiency of the design element are not affected by this deviation request. G. The design life, historical performance, and durability of the design element. The increased slope does not affect design life, historical performance or durability of the roadway. H. The aesthetic and visual impacts of the design element. The increased slope does not impact the aesthetics of the roadway. I. The cost effectiveness and availability of any replacement components or materials. Cost effectiveness/materials are not affected by this deviation request. J. Consistency with the spirit and purpose of the corresponding City design standard. An increase from 8% to 10% is allowed per City standards with City Engineer approval. The project is proposing a maximum of 10% as required to meet another City standard for additional emergency vehicle access. Providing this additional access for public safety while remaining at or below the threshold specified in the standards speaks to the deviation request’s consistency with the spirit and purpose of the standards. K. Demonstration that the environment will not be adversely affected. The environment is not affected by the deviation request. L. Supported by published industry standards. The majority of surrounding, local jurisdictions allow road slopes of up to 12%, with some allowing up to 15%. M. The effect on buildable lands within the City of Auburn. The increase in road slope allows for development of this property, thus increases the buildable land in Auburn. Should the deviation request be denied, an emergency vehicle connection could not be provided thus rendering the property undevelopable. Based on the information/analysis above, the deviation request appears to adhere to the approval criteria. Thank you for your review and coordination in this matter. If you have any questions or concerns regarding the information, please do not hesitate to contact me. Sincerely yours, D. R. STRONG Consulting Engineers Inc. Maher A. Joudi, P.E. Principal, General Manager MAJ/lcs R:\2018\0\18042\Correspondence\Letters\out\L18042_190621_Shannon Howard_Deviation Request.docx 187 of 189 From:Shannon Howard To:"Maher Joudi" Cc:Development; Alexandria Teague Subject:DEV19-0025 Knudson Plat Date:Friday, June 28, 2019 10:54:41 AM Good Morning Maher- The City Engineer has reviewed the Deviation Request (DEV19-0025) submitted for the Knudson Preliminary Plat (PLT18-0006) project. The results of that review are provided below. Deviation Request (DEV19-0025) received June 26, 2019, is associated with the Knudson Preliminary Plat project, a pending submittal. Applicant requests approval of the construction of a public local residential road and emergency vehicle access road with a maximum grade of 10%. Chapter 10.02.4 of the City of Auburn Engineering Design Standards (EDS) requires that vertical grades, or amount of slope of a street in the direction of travel, is limited to 6% for arterials and 8% for all other streets. 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 this case, the City Engineer has determined that the proposal meets or exceeds the corresponding City standards for the Deviation Request. DEV19-0025 is approvable with no conditions. The City will recommend approval of the Deviation Request to the Hearing Examiner for the Knudson Preliminary Plat project. Per Chapter 3, Appendix C of the EDS, approved Deviation Requests must include the appropriate plan sheet callouts and descriptions. Please refer to that section when including the required plan sheet elements for the Deviation Request when submitting for final engineering review of the project. Please let me know if you have any questions. Thank you, Shannon Howard, PE CFM Development Review Engineer Department of Community Development City of Auburn | www.auburnwa.gov Phone: (253) 804-5073 | showard@auburnwa.gov Mailing Address: 25 W Main Street, Auburn, WA 98001 Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map) Customer Service Survey | Application Forms | Zoning Maps 188 of 189 This message is private and privileged. If you are not the person meant to receive this message, please let the sender know, then delete it. Please do not copy or send it to anyone else. 189 of 189