HomeMy WebLinkAboutNE Auburn Special Area Plan EIS Addendum_FINAL-Nov2-2011
NORTHEAST AUBURN / ROBERTSON PROPERTIES
SPECIAL AREA PLAN
Environmental Impact Statement (EIS) Addendum
Addendum Prepared for City of Auburn November 2,2011
Final Environmental Impact Statement July 2004
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Table of Contents
Project Background ............................................................................................................. 1
Purpose of this Addendum .................................................................................................. 2
Addendum to Affected Environment, Impacts, and Mitigation ....................................... 13
Water Resources ....................................................................................................... 13
Plants and Animals ................................................................................................... 21
Transportation ........................................................................................................... 43
Environmental Elements not Analyzed .................................................................... 55
References ......................................................................................................................... 58
List of Figures
Figure 1. Planning Area ..................................................................................................... 5
Figure 2. Auburn Gateway Project Area............................................................................ 7
Figure 3. Parcels in Auburn Gateway II ............................................................................ 9
Figure 4. Site Plan ............................................................................................................ 11
Figure 5. Stream and Wetland Map ................................................................................. 27
List of Tables
Table 1. City of Auburn Wetland Categories (ACC 16.10.080) ..................................... 21
Table 2. City of Auburn Stream Class (ACC 16.10.080) ................................................ 22
Table 3. City of Auburn Minimum and Maximum Wetland Buffers
(ACC 16.10.090) ............................................................................................................... 23
Table 4. City of Auburn Minimum Stream Buffers (ACC 16.10.090) ............................ 23
Table 5. City of Auburn Wetland Mitigation Ratios (ACC 16.10.110) .......................... 24
Table 6. Summary of Wetland Characteristics ................................................................ 30
Table 7. Department of Ecology Functions Summary ..................................................... 31
Table 8. Summary of Wetland and Buffer Impacts ......................................................... 36
Table 9. 2020 Office/Retail; PM Peak Hour Level of Service ....................................... 47
Table 10. 2020 Retail Only; PM Peak Hour Level of Service........................................ 48
Table 11. Road Mitigation Summary............................................................................... 52
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PROJECT BACKGROUND
In July 2004, a Final Environmental Impact Statement (EIS) was published for the
Northeast Auburn/Robertson Properties Special Area Plan. The special area plan was
developed to address a designated ‘special planning area’ and implement policies in the
Auburn Comprehensive Plan. The EIS also covers an application by Robertson Properties
Group (RPG) to redevelop their property located in the area designated as the “Northeast
Auburn Special Plan Area.” The Northeast Auburn Special Area Plan was provisionally
adopted in June 2008 (Ordinance No. 6183). To be implemented the approval was
conditioned on subsequent adoption of a development agreement and a “planned action”
ordinance under Revised Code of Washington (RCW) 43.21C.031. (A more detailed
description of the planning history can be found in the 2004 EIS.)
The Northeast Auburn Special Area Plan covers approximately 90 acres of land (referred
to in the EIS as the “planning area”). The planning area is bordered by Auburn Way
North, South 277th Street, 45th Street NE, and the undeveloped right-of-way of I Street NE
(Figure 1) as it existed within parcel number 0004200006 in 2004. A portion of the I
Street NE right-of-way has been vacated as part of the implementation of the plan.
Within this planning area, RPG owns the Valley Six Drive-in Theater and several
adjacent properties. In addition to a “no action” scenario, the 2004 EIS evaluated three
redevelopment options for the RPG properties to retail, office, and multifamily residential
uses. RPG named its redevelopment proposal “Auburn Gateway”. A core area of RPG’s
holdings together with other properties that RPG was considering acquiring or that could
be cooperatively developed was defined in the EIS as the Auburn Gateway project area.
This area totaled approximately 60 acres. The boundaries of the planning area and the
Auburn Gateway project area as evaluated in the 2004 EIS are shown in Figure 2.
The EIS evaluated the impacts associated with the implementation of the Northeast
Auburn/Robertson Properties Special Area Plan and the Auburn Gateway project. In
addition to the retail, office, and multifamily residential uses, development in this area
would include new roads and utilities, surface parking, and stormwater detention and
water quality facilities. The existing drive-in theater and other structures on the RPG
property would be demolished.
Alternatives evaluated in the EIS of the Auburn Gateway project involved up to 720,000
square feet of retail development, 1,600,000 square feet of office, 500 multi-family
residences, and 6,133 parking spaces. All alternatives evaluated the area outside the
Auburn Gateway project area (the remaining portions of the planning area) as developing
in accordance with existing zoning. This would include multifamily residential
development to the south and east and heavy commercial development to the west.
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PURPOSE OF THIS ADDENDUM
Since the 2004 EIS, RPG has purchased four additional parcels located outside of the
Auburn Gateway project area but within the boundaries of the planning area. The
additional area is located west of D Street NE, north of 49th Street NE and south of South
277th Street. The purchased parcels are shown in Figure 3. The additional properties
would expand the Auburn Gateway project area by approximately 11 acres. The Stein
property, McKee property and SE corner property have not been acquired by RPG, but
remain part of the Auburn Gateway project area in the NE Auburn Special Plan Area.
Therefore, the total size of the RPG holdings is approximately 71 acres. The original
RPG project area evaluated under the 2004 EIS is referred to in this addendum as
“Auburn Gateway I” and the newly acquired properties are referred to as “Auburn
Gateway II.” The Auburn Gateway I and II comprise two parts of the same Auburn
Gateway project. This addendum does not discuss any changes to the plans for the Stein
property, McKee property and SE corner property compared to those covered in the 2004
EIS.
The Auburn Gateway I and II project areas would still involve the same potential
amounts of retail, office, and multi-family residential development evaluated in the 2004
EIS but the development would be spread over a larger geographic area. While retail
development may be the most likely component to develop, other options were studied at
the applicant’s request to preserve the ability to a mixed-use development should market
conditions change.
The transportation analysis in this addendum examines both Alternative 1 (evaluated in
the 2004 EIS as 1,600,000 square feet of office with 200,000 square feet of retail
development) and Alternative 2, assuming a site plan modified to include Auburn
Gateway II and a revised roadway layout as described below. Alternative 1 represents the
worst case scenario. While Alternative 2 represents the applicant’s preferred alternative,
Alternative 1 is included to preserve flexibility for the applicant should market conditions
shift toward more office development.
One proposed change in the road network from the 2004 EIS is that D Street NE north of
49th Street NE is proposed to be vacated and converted to an internal circulation aisle
serving the project. As evaluated in the EIS, D Street NE at Auburn Way North would be
closed with a cul-de-sac. In addition, the applicant requested that the eastward extension
of 49th Street NE east of the proposed I Street NE, which was included in the final EIS to
serve development to the east of the RPG property, be evaluated to determine impacts
from the road not being extended. This addendum includes an assessment of the traffic
impacts of eliminating the northern portion of D Street NE and of not constructing the
eastward extension of 49th Street NE.
Also, since the EIS was prepared, phasing has been proposed for the Auburn Gateway
project. Although the project has always been planned to be built out over a period of
approximately 15 years, the applicant had not previously identified any phasing of the
project or infrastructure for the project evaluated in the EIS. Infrastructure for drainage,
wastewater, and other utilities would be constructed as needed to meet City regulations as
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development progresses. Transportation infrastructure needed to accommodate the
project, in particular development and widening of several roads and providing signals as
needed, is not specified by Code, so it is important to understand what the traffic
demands would be for any interim stages of development. The project could either be
constructed in two phases - one phase would occur north of 49th Street NE and one south
of 49th Street NE - or as a single phase of full site development. The physical location of
the phases does not coincide with the Auburn Gateway I and Auburn Gateway II area
designations. The order in which the phases would occur has not been determined;
therefore the traffic analysis in particular examined several scenarios for phasing to
proceed. RPG has indicated that the order of development (all at once or in two phases,
north or south phase first) is expected to be determined by market conditions once
entitlements are in place.
Also, since the 2004 EIS was prepared, development of nearby properties has proceeded
and City of Auburn regulations and policies have changed. The most notable regulatory
changes affecting the Auburn Gateway Project are the city’s adoption of Ordinance No.
5894, Critical Areas Ordinance, May 2005; Ordinance No. 6283 for the adoption of City
of Auburn Public Work’s Surface Water Management Manual, November 2009;
Ordinance No. 6295, Floodplain Management Regulations, April 2010; and Ordinance
No. 6280 which adopted policy amendments to the City’s Comprehensive Transportation
Plan, December 2009.The purpose of this addendum is to evaluate impacts associated
with adding Auburn Gateway II area to the project and to evaluate the impacts of
constructing in two phases. Neither of these was evaluated as part of the 2004 EIS. The
following environmental elements warrant a detailed discussion of the changes that have
occurred in the affected environment and an evaluation of new impacts associated with
the Auburn Gateway II area and project phasing:
• Water resources
• Plants and animals
• Transportation.
These elements require a detailed discussion because Auburn Gateway II involves
additional floodplain fill, increased impervious surface, fill placed in wetlands, and
changes in vehicle circulation that were not previously evaluated.
The purpose of identifying project phasing is to determine the impacts of constructing
less than the full project at one time and to evaluate what mitigation is associated with
each phase of the project. The amount of development associated with each phase could
vary, depending on market conditions. In order to address the possibility that the
majority of development could be located either in the north phase area or in the south
phase, the transportation impact analysis looked at scenarios allocating to each phase, up
to 60 percent of anticipated development to test whether additional mitigation would be
needed.
Impacts on the remaining environmental elements evaluated in the 2004 EIS
(Geology/Soils, Air Quality, Noise, Hazardous Materials, Cultural and Historic
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Resources, Land Use, Aesthetics, Recreation, Utilities and Public Services) are not
expected to be different from those evaluated in the 2004 EIS and are discussed briefly at
the end of this addendum.
The following sections only assess the changes that have occurred in the affected
environment, environmental impacts, and mitigation measures resulting from changes in
the project plans and/or the environment since the 2004 EIS was published. In all other
instances, the 2004 EIS analysis and conclusions have not changed and the mitigation
measures in the 2004 EIS continue to apply.
The analysis discussed below did not find any significant impacts that were not disclosed
in the 2004 EIS. The information contained in this addendum is provided to allow the
revised project to be evaluated by the City and other regulators, in order to determine
appropriate mitigation for development applications making use of the planned action
EIS.
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Figure 1. Planning Area
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Figure 2. Auburn Gateway Project Area
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Figure 3. Parcels in Auburn Gateway II
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Figure 4. Site Plan
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ADDENDUM TO AFFECTED ENVIRONMENT, IMPACTS,
AND MITIGATION
Water Resources
Applicable Laws and Regulations
Since the 2004 EIS, the City of Auburn has adopted critical area regulations and codified
them in Auburn City Code (ACC) Chapter 16.10 Critical Areas. In addition, ACC
Chapter 15.72 Drainage Plans was repealed and replaced with Ordinance No. 6283 -
Surface Water Management Manual, effective February 16, 2010. The drainage
requirements that would apply to the project are based on equivalency to the Department
of Ecology’s 2005 Stormwater Management Manual for Western Washington (Ecology
2005).
Since the 2004 EIS the National Flood Insurance Program (NFIP) of the Federal
Emergency Management Agency (FEMA) on September 28, 2007 released preliminary
draft Federal Insurance Rate Maps (DFIRMs) that when adopted will revise the extent of
the Green River floodplain in the planning area. Revised preliminary DFRIRMs were
published November 2010. These draft maps indicate a larger and deeper 100-year
floodplain area than the maps that are currently in effect. Since the DFIRM maps have
not been adopted by FEMA the 1995 maps remain in effect from a regulatory standpoint,
based on City code.
In September 2008, a Biological Opinion issued by the National Marine Fisheries Service
(NMFS) determined that the NFIP causes jeopardy to Puget Sound salmonids and
Southern Resident killer whales listed under the Endangered Species Act (NMFS, 2008).
In response to the Biological Opinion, the City of Auburn instituted a moratorium on all
development located in the floodplain per the FEMA maps currently in effect (Resolution
No. 4416). The resolution establishing the moratorium required that applications for
development within floodplain areas may be approved if the applicants meet FEMA and
NMFS requirements for providing adequate protection to endangered species (City of
Auburn, 2008).
On April 5, 2010, the City of Auburn approved interim floodplain regulations (Ordinance
No. 6295; City of Auburn, 2010) which replaced the city’s previous floodplain
regulations and repealed the moratorium. The city received written notification from
FEMA dated September 21, 2011, that FEMA reviewed the City’s interim regulations
and concur they are consistent with FEMA’s model ordinance; the regulations are no
longer interim. The regulations incorporated federal habitat protection requirements and
created a new City floodplain development permit to replace the previous flood zone
control permit. The changes include requiring new developments to prepare a habitat
impact assessment which must include one of the following:
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• A Biological Evaluation or Biological Assessment that has received concurrence
from USFWS or NMFS; or
• Documentation that activity fits within Section 7 or Section 10 of the ESA; or
• An assessment prepared in accordance with Regional Guidance for Floodplain
Habitat Assessment and Mitigation, FEMA Region X, 2010.
New development must be designed and located to minimize the impact on flood flows,
flood storage, water quality and habitat. Stormwater and drainage features must
incorporate low impact development techniques that mimic pre-development hydrologic
conditions. If the project involves more than 10 percent impervious surfaces within the
regulatory floodplain, then the project proponent must demonstrate that there will not be
a net increase in the rate and volume of the stormwater surface runoff that leaves the site.
Structures must be located as far from the waterbody as possible or on the highest land on
the lot (City of Auburn, 2010).
After completion of the Port of Seattle’s compensatory flood storage and wetland
mitigation project located to the south and east of the planning area, and in response to
FEMA’s release of draft Federal Insurance Rate Maps (DFIRM), King County and the
valley cities of Auburn, Kent, Renton and Tukwila (appellants) commissioned NW
Hydraulics Consultants, Inc. to analyze and map the 100-year floodplain for the area. The
report was submitted to FEMA for their consideration during the public appeal period on
the draft floodplain maps. At the time of this writing, the appellants expect that the
DFIRM maps for the planning area will be changed to more closely reflect the NW
Hydraulics Consultant’s study and that ultimately FEMA will adopt the revised maps in
lieu of the DFIRM maps. The timing of FEMA’s adoption is uncertain.
Surface Water
The surface water conditions on the Auburn Gateway I project area were described in the
2004 EIS and have not changed. There have been changes to applicable regulations and
to the adjacent areas that affect surface water. A “Preliminary Feasibility Study” was
developed by RPG’s civil engineers, BCRA Engineering, in December 2007 describing
stormwater conditions at the Auburn Gateway II site (BCRA 2007). Since then, there has
been a new gas station development at the adjacent property to the northwest. Additional
site exploration and a field report by BCRA were completed to review site conditions that
relate to drainage (BCRA 2010). A complete ALTA/topographic survey was completed
by Barghausen Consulting Engineers, Inc. (September 2009) to obtain accurate existing
condition information and update the assumptions and conclusions from the BCRA 2007
preliminary feasibility study. The stormwater conditions described by BCRA are
summarized in this section.
Green River Floodplain
Since the 2004 EIS, the Port of Seattle has completed construction of the compensatory
flood storage and wetland mitigation project described in the 2004 EIS. That project was
designed to compensate for fill of the entire FEMA-identified floodplain area south of
South 277th Street in northeast Auburn based on the 1995 FIRM maps. According to the
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2004 EIS this was roughly 60 acre-feet in the planning area. A subsequent report:
“Federal Emergency Management Agency Conditional Letter of Map Revision”, July
2007 by Parametrix, Inc. prepared for the purpose of application to FEMA identifies
approximately 66.2 acre feet of storage was constructed within the Port of Seattle
Property. The report also indentifies that the volume of fill for areas south of S 277th St
and East of Auburn Way North, below the 45 foot elevation would be less than the
volume of the constructed flood storage, again based on the 1995 FIRM maps. FEMA’s
processing of the Conditional Letter of Map Revision (CLOMR) has not been completed.
However, depending on the final FIRM maps, and if they show a greater floodplain
volume, there may not be adequate compensatory flood storage to mitigate for any
additional flood volume as a result of filling and development in the floodplain.
The City of Auburn and the Port of Seattle are in the process of amending an existing
City and Port Interlocal Agreement to allow the Port’s wetland mitigation property to be
used to compensate for filling nearby properties located in the floodplain including the
project site based on the 1995 FIRM maps.
Storm Drainage
Runoff from the Auburn Gateway II site sheet flows towards the northeast portion of the
site, along the elevated roadway of South 277th Street. The north edge of the site consists
of a roadside ditch running along its entire length. The topographic survey shows the
ditch generally sloping slightly to the east. Auburn Way North has curb, gutter, and storm
conveyance system along the west side of the site. Most of the site is approximately 4 to
6 feet lower in elevation than the road level of Auburn Way North (BCRA, 2007). See
also Figure 8, Existing stormwater drainage and Green River floodplain conditions, page
73, Draft EIS.
The Auburn Gateway II site appears to receive offsite surface waters from the following
sources:
• A 36-inch culvert under D Street NE which conveys stormwater from Auburn
Gateway I towards the northeast corner of the Auburn Gateway II site. The
culvert under D Street NE has been damaged by the weight of the road.
• The developed property located to the northwest of the Auburn Gateway II site (at
the southeast quadrant of the Auburn Way North and South 277th Street
intersection) that conveys surface runoff to the S 277th Street roadside ditch site
via an overflow pipe. The offsite property has a storm drainage control structure
and an apparent water quality treatment device installed. The offsite property is
elevated about 6 feet above the site.
• Surface water runoff from Auburn Way North which enters the site at the
northwest corner. Approximately 800 feet of roadway runoff from Auburn Way
North is conveyed via underground storm pipe north to South 277th Street, turns
east and then discharges into the ditch along the north edge of the site along South
277th Street (BCRA, 2007).
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Surface runoff from Auburn Gateway II exits the site through a 48-inch culvert near the
northeast corner, flowing underneath South 277th Street. Some of the site runoff also
collects in the northwest corner of the site (BCRA, 2007). As described in the Draft EIS,
the surface runoff continues from South 277th Street and the 48-inch culvert along the
west side of 86th Avenue South, then under 86th Avenue South within a 7-foot by 5-foot
concrete box culvert conveying water to the north to the Green River. The ditch is known
as Auburn Creek (Stream Number 0056), although it has been channelized for most of
the distance to the Green River.
Since the 2004 EIS was published, a residential subdivision and planned unit
development (PUD) was constructed on a 40.9-acre site east of the planning area. The
Trail Run (previously called River Sands) development involved the construction of
houses, townhouses, roadways, and stormwater facilities. Stormwater runoff from the site
is retained and treated on-site, and then directed west to the roadside ditch along South
277th Street which continues north along 86th Avenue South in Auburn Creek to an
outfall at the Green River. According to the Supplemental Downstream Storm Drainage
Analysis for River Sands PUD the pre-development rate of runoff from Trail Run during
the 100-year design storm is 8.5 cubic feet per second (cfs) and the 100-year post-
developed conditions would be 7.57 cfs (DBM Consulting Engineers, 2005). Therefore,
assuming the system is working as designed, the rate of stormwater runoff from the Trail
Run property has decreased since the 2004 EIS was prepared.
The City has determined that the ditches along the south side of South 277th Street are
not regulated as streams under the City’s critical areas ordinance, but are regulated by the
City’s Flood Hazard Area regulations as typed waters using the DNR water typing
system. These water bodies are therefore referred to as drainage ditches in this EIS
addendum, to distinguish them from water bodies that the City regulates as streams.
Surface Water Quality
The EIS refers to the 1998 Ecology 303(d) list when describing water quality conditions
for the Green River. Since that time, Ecology has issued two more 303(d) lists, one for
2004 and one for 2008. According to the 2008 Ecology 303(d) list the Green River
adjacent to the planning area is still listed as having elevated temperature. The 303(d) list
also indicates that fecal coliform bacteria and temperature still do not meet standards in
the Green River reaches located several miles downstream. Dissolved oxygen has been
added as not meeting standards. The Green River in the project area is no longer listed as
not meeting standards for chromium (Ecology, 2008).
In addition to the pollutant loadings from the Auburn Gateway I site that were described
in the EIS, the site containing the proposed Auburn Gateway II likely contributes
pollutants associated with agricultural production such as herbicides for weed control,
similar to those expected on parts of the Auburn Gateway I site.
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Impacts
Short Term Construction Impacts
Project construction phasing was not evaluated in the 2004 EIS. The applicant may
develop Auburn Gateway I and II in two phases; one phase north of 49th Street NE and
one phase south of 49th Street NE or as a single phase. If phased, the order in which the
phases would occur has not been determined. Short term impacts associated with
construction would be similar to what was described in the 2004 Draft EIS. While
Auburn Gateway I and II may be constructed in two phases, the cumulative impacts
associated with incremental development would be limited.
The 2004 EIS estimated approximately 650,000 cubic yards of fill and 250,000 cubic
yards of excavation would be necessary to allow for proper drainage of stormwater using
a combination of gravity and pump systems. If the stormwater system was designed to
function by gravity alone, 650,000 cubic yards of fill would be necessary.
Based on the current site plan and addition of the Auburn Gateway II property, RPG is
currently proposing to fill approximately 600,000 to 750,000 cubic yards for the Auburn
Gateway I and II sites. Since the type of stormwater detention facilities have yet to be
determined, this volume of earthwork should be considered an estimate. Grading for the
Auburn Gateway project would consist of importing and placing fill material sufficient to
allow for proper drainage of stormwater and to elevate the building pads out of the 1995
100-year FEMA floodplain as a minimum. Grading would accommodate a gravity system
that has an outlet to the existing ditch along South 277th Street or as modified. Any
phasing that would occur would be required to address floodplain regulations in effect for
each phase.
Impacts associated with fill would be similar to those described in the 2004 EIS, except
that additional trucks would be involved in importing and exporting material. With the
additional 11 acres of development, there could be a higher potential of soil and sediment
deposition on the streets in the project area. Placement of more imported fill material in
the project area could increase the potential for erosion. These potential impacts would be
avoided by implementing best management practices and complying with Washington
State Department of Ecology requirements for temporary erosion control, grading, and
drainage, as described in the 2004 EIS, the City of Auburn Surface Water Management
Manual, November 2009, and the Washington State Department of Ecology 2005
Stormwater Management Manual for Western Washington. The contractor will also be
required to obtain a Construction Stormwater General Permit through the Department of
Ecology and the National Pollutant Discharge Elimination System permit.
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Long Term Operational Impacts
Surface Water
Green River Floodplain
Volume of Floodplain Storage Affected
Because the Port of Seattle wetland mitigation site provided floodplain compensation for
filling the floodplain in the entire floodplain area south of South 277th Street, the filling
of floodplain on the Auburn Gateway II site can be compensated for based on the 1995
FIRM maps. The 2004 Final EIS estimated Up to 27.5 acre-feet of floodplain storage
volume would be filled within the Auburn Gateway project area based on the 1995
FEMA floodplain. The Auburn Gateway II site would require approximately 6.23 acre-
feet of floodplain fill, for a total of 33.73 acre feet (BCRA 2011) Because the
calculations regarding volume of flood storage available in the Port’s property were
based on the adopted 1995 100-year floodplain maps, these calculations do not consider
the differences in floodplain volumes that would result based on the proposed DFIRMs.
Therefore, additional floodplain compensation may be needed for filling the floodplain if
the floodplain volumes established by the DFIRM maps once they are adopted are higher
than the current 1995 FIRM maps. Additional floodplain compensation would be
provided in compliance with applicable city regulations pursuant to a flood development
permit and habitat impact assessment.
Connection of Wetland Flood Storage to Existing Floodplain
According to the 2004 EIS, the Port of Seattle was obligated to construct a flood
conveyance channel from the newly created wetland north to the roadside ditch along the
south side of South 277th Street. After a flood event, excess water stored in the newly
created wetland mitigation/floodplain storage site would drain along the flood
conveyance channel to the roadside ditch. The provision of this channel was a
requirement in the interlocal agreement between the Port of Seattle and the City of
Auburn in order to make sure the wetland is connected to the remaining Green River
floodplain located north of the roadway. The Port of Seattle constructed the flood
conveyance channel as required by the interlocal agreement to make connectivity to the
floodplain. At the time of the 2004 EIS, the Port reported that the capacity of the roadside
ditch on the south side of South 277th Street that connects to the Port’s flood conveyance
channel is not sufficient to convey the 100-year flood volume (Wessels 2003 personal
communication). Once the Auburn Gateway project site is filled and areal extent of the
floodplain is reduced, the capacity of the roadside ditch along the south side of South
277th Street would need to be increased to adequately manage the flood waters being
conveyed from the wetland mitigation /floodplain storage to maintain connectivity to the
floodplain which originates within unincorporated King County to the north. The
roadside ditch would be relocated as part of the roadway widening proposed for South
277th Street. RPG has indicated that the relocated roadside ditch and culvert system will
be designed to accommodate the 100-year 24-hour peak flow rate and fish passage
criteria (if required) per Chapter 3 of the City of Auburn Surface Water Management
Manual November 2009.
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In the 2004 EIS, the roadside ditch along 277th Street was considered to be several
interconnected wetlands (Wetland Ditches H, I and J). Washington Department of Fish
and Wildlife (WDFW) determined that the wetlands are actually a stream (J.S. Jones and
Associates letter to WDFW, dated June 15th, 2009, confirming results of site visit with
WDFW), however this determination may not affect determinations of other regulatory
agencies. In the 1990s, as part of a 272nd / South 277th Street improvement project, west
of Auburn Way North, the City of Kent created wetland mitigation credit by completing
wetland mitigation for the proposed filling of the wetland ditches as they existed then
along South 277th Street. The applicant may petition regulatory agencies to apply the
wetland mitigation credit that was established at the time to the wetland ditches if the
ditches are currently considered to be wetland by the U.S. Army Corps of Engineers
(COE). The applicability of the credits would be at the discretion of each permitting
agency and the City of Kent, which constructed the mitigation and owns the credits. Any
shortfall in wetland mitigation may require additional wetland mitigation. See Plants and
Animals-Affected Environment for more detailed information.
Storm Drainage Systems
The stormwater system for Auburn Gateway I and II would include conveyance systems
and the use of either above ground stormwater detention facilities/ponds, underground
detention vaults/tanks, or a combination thereof to provide stormwater quality and
quantity control. Based on current topography and existing basins, there could be two or
three detention systems used to control storm water runoff. Grading on site will
accommodate a gravity system that has an outlet to the existing ditch in South 277th
Street or as modified.
More specifically, for Auburn Gateway II storm drainage connections would be made to
the future storm improvements in South 277th Street and to the 48-inch culvert crossing
under South 277th Street. It is anticipated that an underground detention tank would be
the preferred method of stormwater detention onsite. For example, based on impervious
coverage of 80 percent for the total 11-acre Auburn Gateway II site, approximately
200,000 cubic feet of storage would be required for detention (BCRA, 2007), based on
the previous stormwater management design standards. Since this time, the City has
adopted a new Surface Water Management Manual (November 2009). The impervious
surface amount for the Auburn Gateway II site is not known at this time and could be
lower than 80 percent, and detention requirements could also be reduced through use of
low impact development methods. The project will be expected to meet the design
requirements and stormwater management code as required by the City of Auburn. To
ensure coordination of the future storm system over the project area in conformance with
proposed phasing and city codes, a master storm drainage plan is to be prepared prior to
construction authorizations.
In addition, if the storm drainage discharge from the project is not as proposed in
previous drainage analysis prepared for the purposes of the EIS (“Hydraulic Model
Evaluation of Potential Drainage System Impacts Associated with the Auburn Gateway
Project”, Herrera, 2003) and the discharge is all directed to either: South 277th Street
(EIS Scenario 3a) or split evenly between South 277th Street and D Street NE (EIS
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Scenario 3b), then additional downstream drainage analysis shall be required as directed
by the City Engineer prior to construction authorizations.
If all the storm drainage discharge from the project is directed to South 277th Street (EIS
Scenario 3a) the applicant shall design the master plan to include the following storm
drainage improvements for any phase of development:
• Replace the existing storm drainage pipe located in D Street NE with a 36-inch
pipe in D Street NE from South 277th Street to Auburn Way North.
The master storm drainage plan shall also define which improvements are to be
constructed concurrent with each phase of the project (North Phase, South Phase, or
Combined North and South Phases).
Stormwater for the pollution-generating impervious surfaces on the Auburn Gateway II
site would be treated as required by the City of Auburn. Pre-cast water quality vaults with
filter cartridges will likely be used for treatment per the current site plan. Other treatment
options would include bio-retention facilities, open treatment ponds, and low-impact-
development methods (BCRA, 2007).
To provide for adequate storm drainage and conveyance to the point of discharge at the
northeast corner of the Auburn Gateway II site, the site at the south and southwest ends
would need to be at an approximate elevation of 56 feet. There would be significant
amount of fill required to allow for draining the site to the northeast. It is anticipated that
the site would need to be raised approximately 5 to 7 feet in some areas to allow for
gravity drainage to the culvert at South 277th Street and D Street NE (BCRA, 2007).
With the construction of on-site detention facilities, stormwater runoff from the Auburn
Gateway II site is expected to be the same or less than the current rate of runoff.
Stormwater facilities for both the Auburn Gateway I and II sites would be designed to
comply with the City of Auburn Surface Water Management Manual, November 2009,
effective February 16, 2010. The City’s Surface Water Management Manual is
equivalent to the Washington State Department of Ecology 2005 Stormwater
Management Manual for Western Washington.
Significant Unavoidable Adverse Impacts
As stated in the 2004 Draft EIS, no significant unavoidable adverse impacts on water
resources would occur if the mitigation requirements and recommendations provided in
the Draft EIS are followed. To avoid impacts on ESA listed species and habitats, the
development must meet City floodplain development permit standards and FEMA and
NMFS requirements for providing adequate protection to endangered species.
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Plants and Animals
Applicable Laws and Regulations
At the time the 2004 EIS was issued, the City of Auburn relied on adopted SEPA policies
and used the SEPA process to identify impacts and mitigation for environmentally critical
areas. General guidance from the City of Auburn Comprehensive Plan regarding the
protection of critical areas was also used as a guide for assessing impacts. Since that time,
the City of Auburn has developed critical area regulations codified in Auburn City Code
(ACC) 16.10 Critical Areas. Therefore, the following sections serve as an update to the
2004 EIS and replace the analysis regarding the Mill Creek Special Area Management
Plan.
The City’s Critical Areas regulations (ACC 16.10) contain the definitions for regulated
wetlands and streams, wetland categorization criteria, buffer standards and permit
standards and procedures.
Wetlands in the City of Auburn are to be classified according to the criteria under ACC
16.10.080, summarized in Table 1.
Table 1. City of Auburn Wetland Categories (ACC 16.10.080)
Category I Represent a unique or rare wetland type; or
Are more sensitive to disturbance than most wetlands; or
Are relatively undisturbed and contain ecological attributes that are impossible to
replace within a human lifetime; or
Are providing a high level of functions, scoring 70 points or more out of 100
(DOE Wetlands Rating System, 2004); or
Are characterized as a national heritage wetland; or
Are characterized as a bog; or
Are over one acre and characterized as a mature and old-growth forested wetland.
Category II Provide high levels of some functions, being difficult, though not impossible to
replace; or
Perform most functions relatively well, scoring 51 – 69 out of 100 points (DOE
Wetlands Rating System, 2004).
“Category III wetlands” are those wetlands that are not Category I or II wetlands,
and which meet the following criterion:
Provide moderate levels of functions, scoring between 30 and 50 out of 100
points (DOE Wetlands Rating System, 2004).
Category III Provide moderate levels of functions, scoring between 30 and 50 out of 100
points (DOE Wetlands Rating System, 2004).
Category IV Provide low levels of functions, scoring less than 30 out of 100 points (DOE
Wetlands Rating System, 2004).
Source: City of Auburn, 2009
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According to ACC 16.10.080 wetlands that are artificially created are not regulated.
“Artificially created wetlands are purposefully created landscape features, ponds
and storm water detention or retention facilities. Artificially created wetlands do
not include wetlands created as mitigation, and wetlands modified for approved
land use activities. Purposeful creation must be demonstrated to the director
through documentation, photographs, statements and/or other evidence. Artificial
wetlands intentionally created from nonwetland sites are excluded from regulation
under this section.” (ACC 16.10.080[C][5])
Streams in the City of Auburn are to be classified according to the criteria under ACC
16.10.080, summarized in Table 2.
Table 2. City of Auburn Stream Class (ACC 16.10.080)
Class I
Streams
Natural streams identified as “shorelines of the state” under the city of Auburn
shoreline master program.
Class II
Streams
Natural streams that are not Class I streams and are either perennial or intermittent
and have one of the following characteristics:
Contain fish habitat; or
Has significant recreational value, as determined by the director.
Class III
Streams
Natural streams with perennial (year-round) or intermittent flow and do not contain
fish habitat.
Class IV
Streams
Natural streams and drainage swales with channel width less than two feet taken at
the ordinary high water mark, that do not contain fish habitat.
Source: City of Auburn, 2009
According to ACC 16.10.080 streams that are intentionally created are not regulated.
“Intentionally created streams are those manmade streams defined as such in
these regulations, and do not include streams created as mitigation. Purposeful
creation must be demonstrated through documentation, photographs, statements
and/or other evidence. Intentionally created streams may include irrigation and
drainage ditches, grass-lined swales and canals. Intentionally created streams are
excluded from regulation under this section, except manmade streams that
provide “critical habitat,” as designated by federal or state agencies, for
salmonids.” (ACC 16.10.080[D][5])
Regulated wetlands and streams are protected by buffers, defined as a “naturally
vegetated, undisturbed, enhanced or revegetated zone surrounding a critical area that
protects the critical area from adverse impacts to its integrity and value, and is an integral
part of the resource’s ecosystem” (ACC 16.10.020).
Table 3 lists the required buffer widths for wetlands in Auburn.
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Table 3. City of Auburn Minimum and Maximum Wetland Buffers
(ACC 16.10.090)
Wetland Category Minimum Buffer Width Maximum Buffer Width
Category I 100 feet 200 feet
Category II 50 feet 100 feet
Category III 25 feet 50 feet
Category IV 25 feet 30 feet
Source: City of Auburn, 2009
Table 3 displays the minimum and maximum buffer requirements to be applied to
wetlands in Auburn. The maximum buffer may be required if the Planning and
Development Director determines that a larger buffer is necessary to protect wetland
functions and values based on site conditions, site design, intensity and operational
characteristics of the development/land use (ACC 16.10.090[E][1][g]). Buffer width
requirements may be averaged where it is demonstrated that:
• The wetland contains variations in sensitivity due to existing physical
characteristics;
• Lower intensity land uses would be located adjacent to areas where buffer width
is reduced;
• Width averaging will not adversely impact the wetland functional values; and/or
• The total area contained within the buffer after averaging is no less in area than
contained within the standard buffer prior to averaging.
When buffer width averaging is allowed, the buffer reduction cannot result in a reduction
greater than 35 percent of the required buffer.
Table 4 lists minimum required buffer widths for streams in Auburn.
Table 4. City of Auburn Minimum Stream Buffers (ACC 16.10.090)
Stream Class Minimum Buffer Width
Class I
(see subsection (E)(2)(b) of this section) 100 feet
Class II 75 feet
Class III 25 feet
Class IV 25 feet
Source: City of Auburn, 2009
The minimum buffer widths established in Table 4 may be increased or averaged by the
Planning and Development Director in response to site-specific conditions and based on
the information characterizing the functions and values of the stream (ACC
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16.10.090[E][2]). Buffer width averaging may be allowed for Class II and Class III
streams only when all of the following are met:
• One or more enhancement measures are implemented (as listed in ACC 16.10.090
(E)(2)(b)(i) through (iv), which include removing or modifying stream culverts,
planting native vegetation within buffer);
• The total area contained within the buffer after averaging is no less in area than
contained within the standard buffer prior to averaging;
• The buffer width averaging will result in stream functions and values equal or
greater than before averaging; and
• The buffer width is not reduced by more than 35 percent in any location than the
required buffer widths.
In circumstances where wetland alterations are allowed by the Planning and
Development Director, the following acreage replacement and enhancement ratios must
be implemented:
Table 5. City of Auburn Wetland Mitigation Ratios (ACC 16.10.110)
Wetland Category Wetland Creation Ratio (Acres) Wetland Enhancement Ratio (Acres)
Category I 6:1 12:1
Category II
Forested 3:1 6:1
Scrub/Shrub 2:1 4:1
Emergent 2:1 4:1
Category III Forested 3:1 6:1
Scrub/Shrub 2:1 4:1
Emergent 2:1 4:1
Category IV* 1.25:1* 2.5:1*
*Category IV wetlands can either be mitigated by either: (a) meeting one of the replacement ratios; or (b) implementing
mitigation which ensures no net loss of values and functions of the larger ecosystem in which the critical area is
located.
Source: City of Auburn, 2009
The City of Auburn identifies floodplain as a regulated critical area. The City also
regulates portions of the site as flood hazard areas under Chapter 15.68 ACC Flood
Hazard Area regulations. These regulations require that development be adequately
elevated and floodproofed, and that development not reduce effective base flood storage.
If a project involves placement of fill in a floodplain, an equivalent compensatory
floodplain storage volume must be provided at equivalent elevations to that being
displaced and must be hydraulically connected to the floodplain.
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Affected Environment
Plant Communities
Wetlands
Wetlands in the project area were not delineated or categorized in the 2004 EIS. Since
that time J.S. Jones and Associates, Inc. prepared a Wetland and Stream Impact
Assessment (J.S. Jones and Associates, Inc., 2010). The assessment delineated and
categorized Wetlands A, B, C, and D, all of which are located at least partially within the
Auburn Gateway I project area. The report also describes Wetland E, which is located in
the Auburn Gateway II project area and is discussed in more detail below. Wetland E
was not delineated but is described in the J. S. Jones Report (2010).
Wetland F is a wetland located on the Port of Seattle mitigation site to the east
(Parametrix, 2003). Wetland G located on the north side of Auburn Gateway II project
area is considered to be a roadside drainage ditch for stormwater conveyance rather than
a wetland, as characterized in the 2004 EIS. As a drainage ditch, it is not considered a
wetland or stream in the City code, although alterations to the ditch may be regulated by
other agencies, as described below.
Wetland ditches H, I, J, and K have been determined by the Washington Department of
Fish and Wildlife (WDFW) to be intermittent fish bearing waters rather than wetlands, as
characterized in the 2004 EIS (J. S. Jones and Associates, Inc., 2009). Based on
information provided by the applicant, in the Stream Determination Request Letters from
J. S. Jones and Associates dated September 15, 2009 and December 9, 2009, the City has
determined that the roadside ditches on the south side of S 277th Street would not be
regulated under the city’s critical areas regulations (Chapter 16.10 ACC). However, the
various regulatory agencies have different authority and as a result their determinations
may be different.
The U.S. Army Corps of Engineers (COE) was consulted to determine if their prior
jurisdictional determination, evaluated in the 2004 EIS, has changed given WDFW’s
determination that the wetland ditches are streams. The COE indicated in a letter to Mr.
Jeffery Jones received May 10, 2010 that ditches identified as Wetlands G, H, I, J and K
in the 2004 EIS would be regulated by the COE as “waters of the US”, rather than
wetlands, and confirmed the locations of the wetland boundaries for Wetlands A, B , C,
and D (COE 2010). The Wetland and Stream Impact Assessment J.S. Jones and
Associates, Inc., 2010 evaluated wetland ditches G, H, I, J and K as a stream as discussed
in the Stream section below. See Figure 5 for the location of wetlands, streams, and other
drainage features in the project area.
Wetland E is located in the Auburn Gateway II project area. There is uncertainty about
the extent of the wetland. The Mill Creek SAMP identifies wetland as 1.5 acres in size.
The Draft EIS identified the wetland as approximately 0.20 acre. In 2008, Ecological
Land Services, Inc. (ELS) delineated and categorized the wetland and submitted the
report to the COE at the request of the property owner at the time. In 2008, ELS
delineated and categorized the wetland as a 1.53-acre Category III wetland (ELS, 2008).
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The COE conducted a field visit and responded to ELS that the delineation was incorrect.
Since ELS did not provide a response, the application was rejected by the COE. The
Auburn Gateway II property receives stormwater runoff from an adjoining property to the
northwest bringing the actual extent of the wetland under question. Because a similar
estimated area was provided for this wetland in the Mill Creek SAMP, the 1.53-acre
estimate is used for this addendum, with the understanding that a full delineation will be
required prior to development approvals, and mitigation will be required pursuant to the
City’s and the COE’s requirements or those of other agencies at that time. The applicant
proposes to delineate and categorize the wetland during the City’s permit submittal
process. At this time, the wetland is assumed to be a Category IV depressional wetland
with a Palustrine Emergent (PEM) vegetation class, as described in the Wetland and
Stream Impact Assessment report (J.S. Jones and Associates, Inc., 2010).
Wetlands G, H, I, J, and K are described in more detail below under the heading:
Streams.
In 1996 the City of Kent applied for permits for the 272nd / South 277th Street
improvement project. This project involved widening South 277th Street, generally west
of Auburn Way North and filling what were considered at that time to be wetland ditches
G, H, I and J. A Clean Water Act Section 404 permit was issued by the COE for the
project in 1996 that required wetland mitigation for filling the wetland ditches. The City
of Kent completed the required wetland mitigation, thereby creating wetland mitigation
credit however the Wetlands G, H, I, J, and K were never filled. The wetland mitigation
credit may be applied to the wetland ditches as originally intended; if the ditches are
currently considered to be wetland by the COE. If the ditches are not considered
wetlands, the credits could be used towards other wetland fill, including possibly the
Auburn Gateway project. The applicability of the credits would be at the discretion of
each permitting agency and the City of Kent, which constructed the mitigation and owns
the credits.
The Hydrogeomorphic Classification (HGM) of Wetlands A-E varies between riverine,
depressional, and slope. Wetland classifications according to the Cowardin system vary
between Palustrine Emergent (PEM), Palustrine Scrub-Shrub (PSS), and Palustrine
Forested (PFO). The following sections describe the three Cowardin communities that are
present within the Auburn Gateway I and II project area as portrayed in the Wetland and
Stream Impact Assessment (J.S. Jones and Associates, Inc., 2010).
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Figure 5. Stream and Wetland Map
This Page Intentionally Left Blank
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Palustrine Forested Wetland (PFO)
Two palustrine forested wetlands are located in the Auburn Gateway I and II project area
(Wetland B and D). Wetland B is a Category II depressional wetland that extends beyond
the Auburn Gateway I project area. Within the project area it is approximately 0.01 acres
in size. The off-site portion of Wetland B was not delineated since permission to access
the Stein property was not given. Wetland B is dominated by black cottonwood (Populus
trichocarpa), Sitka willow (Salix sitchensis), and unidentified grasses. The on-site buffer
north of Wetland B has been enhanced with native vegetation for a width of 35 feet.
Wetland D is a Category II riverine wetland that it is approximately 0.06 acres in size.
The April 2003 wetland delineation report for the Port of Seattle indicates that this
wetland does not extend onto the Port property (Parametrix 2003). Wetland D is
dominated by black cottonwood and red-osier dogwood (Cornus stolonifera). The
vegetated buffer (as established by ACC 16.10) is disturbed and dominated by black
cottonwood, red alder (Alnus rubra), and Himalayan blackberry.
Palustrine Scrub-Shrub Wetland (PSS)
Wetland B is the only wetland within the Auburn Gateway I and II project area that
contains a palustrine scrub-shrub wetland; it also includes portions that are palustrine
forested and palustrine emergent.
Palustrine Emergent Wetland (PEM)
Four palustrine emergent wetlands are located in the Auburn Gateway I and II project
area (Wetlands A, B, C, and E). Wetland A is a Category II riverine wetland that is
approximately 0.14 acres in size. According to the Parametrix Port of Seattle delineation,
Wetland A does not extend offsite (Parametrix, 2003). Wetland A is dominated by
meadow foxtail (Alopecurus sp.). Existing buffers (as established in ACC 16.10) are
gravel surfaces to the south and west of Wetland A and previously disturbed black
cottonwood (Populus trichocarpa), Himalayan blackberry (Rubus discolor) and grasses
to the north and east.
As discussed above, a portion of Wetland B is palustrine emergent. Wetland C is a
Category III slope wetland approximately 0.39 acres in size. The perimeter of the
wetland is silt fenced as it was previously delineated. There is a surface water inlet
structure near the north end of the wetland that connects to the existing Auburn Valley 6
Theaters’ storm drainage system. The inlet structure controls the peak water levels of the
wetland. A 35-foot wetland buffer around the perimeter of the wetland was planted with
native vegetation in the fall of 2005.
Wetland E located in Auburn Gateway II project area has not been delineated or
categorized. It is assumed to be a Category IV depressional wetland. The wetland is
dominated by creeping buttercup (Ranunculus repens) and reed canarygrass (Phalaris
arundinacea).
Table 6 summarizes the wetland areas and classifications for Wetlands A, B, C, D, and E.
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Table 6. Summary of Wetland Characteristics
WetlandA
Wetland Classification Wetland Size
(acre) CowardinB HGMG EcologyC Local
JurisdictionD
A PEM Riverine II II 0.14
B PFO, PSS,
PEM
Depressional II II 0.01E
C PEM Slope III III 0.39
D PFO Riverine II II 0.06E
E PEM Depressional IVF IVF UnknownF
Source: J.S. Jones and Associates, Inc., 2010
A) Refer to Figure 5 for wetland general locations.
B) PEM = Palustrine Emergent; PSS = Palustrine Scrub-Shrub; PFO = Palustrine Forested.
C) Ecology rating according to Washington State wetland rating system for Western Washington, Revised.
Ecology publication #04-06-15.
D) Auburn City Code Chapter 16.10.080.C.
E) The Wetland continues off-site; only the on-site area is listed
F) Wetland has not been delineated or classified, but will be delineated at the time of permit application.
G) Hydrogeomorphic Classification (HGM)
Functional Analysis
Functions were assessed by J.S. Jones and Associates, Inc. (2010) using the Washington
State Department of Ecology Wetland Rating Form – Western Washington.
Wetland A provides low habitat and moderate water quality and hydrologic functions.
Auburn Valley 6 Theaters’ drainage ditches and culverts discharge to the wetland. The
wetland is composed of dense grass. Wetland A is a tributary to Auburn Creek and the
Green River. Flow-through is rapid. Over bank flooding occurs seasonally. Habitat
features and vegetation structure is absent.
Wetland B is rated moderate for water quality and low for habitat and hydrology. The
presence of invasive plants in the understory and the small wetland size are the reasons
for the low habitat and hydrology scores. Water quality is moderate because the ability
and opportunity to improve water quality are present.
Wetland C is rated moderate for hydrology, moderate for water quality and low for
habitat. Wetland C is considered a “slope” wetland because it is not in a depression
where it could hold water. For a “slope” wetland, the hydrology value for the Wetland C
is the maximum possible. However, “slope” wetlands have less potential points. The
grass community limits habitat functions and the small wetland size limits the ability for
water retention. Water quality is moderate because the ability and opportunity to
improve water quality are present.
Off-site Wetland D is rated moderate for water quality, hydrology and habitat. The
wetland has seasonal flooding from the adjacent ditch. There is opportunity to improve
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water quality. Habitat values are provided by the vertical vegetative structure and by
being adjacent to a stream.
Wetland E has not been delineated or fully assessed for functions. The wetland is
currently under agricultural use. Although the functions for this wetland have not been
formally assessed, initial observations suggest that Wetland E has moderate functions for
water quality since it has an unconstricted outlet. It also can treat pollutants from
surrounding residential areas since it has un-grazed vegetation. It has moderate
hydrologic functions as it has a 2- to 3-foot depression that can store water at peak storm
events. Storage prevents excessive flows to the Green River which can potentially
damage salmon redds further downstream. It has low habitat functions since it has an
absence of intact buffers, connections to open space and habitat features that include
standing snags, fallen logs and amphibian habitat.
Table 7 provides a summary of the functions assessed for each wetland.
Table 7. Department of Ecology Functions Summary
Functions Wetland A Wetland B Wetland C Wetland D Wetland E1
Water quality Moderate Moderate Moderate Moderate Not assessed
Hydrology Moderate Low Moderate Moderate Not assessed
Habitat Low Low Low Moderate Not assessed
1: Although wetland functions have not been assessed for Wetland E, it is likely to be considered moderate
for water quality and hydrology, and low for habitat since it is actively farmed. The functions will be
assessed at the time of the wetland delineation.
Source: J.S. Jones and Associates, Inc., 2010
Streams
The wetland ditches described in the 2004 EIS as Wetlands H, I, J and K have been
determined by WDFW to be streams as the agency defines them. Wetland ditch G is not
considered a stream by WDFW; however, it is anticipated that the COE will regulate the
road ditch as a “Water of the U.S.” Based on information provided by the applicant, in
the Stream Determination Request Letters from J. S. Jones and Associates dated
September 15, 2009 and December 9, 2009, the City has determined that the roadside
ditches on the south side of S 277th Street would not be regulated under the city’s critical
areas regulations as either wetlands or streams (Chapter 16.10 ACC). However, the
various regulatory agencies have different authority and as a result their determinations
can differ. The COE has been consulted to determine if their prior jurisdictional
determination, evaluated in the 2004 EIS, has changed given WDFW determination that
the wetland ditches are streams not wetlands (J. S. Jones and Associates, Inc., 2010).
Auburn Creek (Stream Number 0056) is located along 86th Avenue South and is a
tributary to the Green River. The roadside ditch along the south side of South 277th
Street and the stream along the east property line of the Auburn Valley 6 Theaters and the
Stein Property (previously identified as Wetland ditch K) are two tributaries of Auburn
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Creek. There is a ditch that runs through Wetland A and connects to the east side stream
(J. S. Jones and Associates, Inc., 2010).
The South 277th Street roadside ditch and the east side stream both have the potential to
be fish-bearing (previously identified as Wetland ditches H, I & J). Surface flow is
intermittent and seasonal. The roadside ditch and east side stream are classified as Type
F waters according to WDFW. The existing buffer of the South 277th Street roadside
ditch is road shoulder to the north side and where adjacent to the drive-in theater
(Wetland ditch H & I) is a narrow strip, less than 10 feet wide, containing Arborvitae
trees and chain link fence on the south side. The understory is Himalayan blackberry,
red-osier dogwood, and willow. The existing south side buffer of Wetland ditch J is
mixed second growth forest as identified in the 2004 EIS.
The ditch through Wetland A is not fish-bearing and carries flowing water intermittently.
There is an elevation drop of several feet from the east end of Wetland A to the east side
stream (identified as Wetland ditch K). The stream is densely vegetated with grass most
of the year (J. S. Jones and Associates, Inc., 2010).
Functions
Auburn Creek is an intermittent stream that may provide potential spawning and juvenile
rearing habitat for salmonids; however, this has not been confirmed. There is a large flap
gate at the outfall to the Green River that does not prevent fish passage. The South 277th
Street ditch and 48-inch culvert under S 277th Street connects to farm ditches north of
South 277th Street, which become Auburn Creek. The farm ditches are annually sprayed
and cleaned with a backhoe. Seasonal flows, stream temperatures, sedimentation, water
quality, and channel conditions limit the potential of fish usage (J. S. Jones and
Associates, Inc., 2010).
WDFW fisheries biologist, Larry Fisher, classified the eastern drainage and South 277th
roadside ditch, east of D Street NE, as intermittent potential fish-bearing waters. No fish
have been observed south of South 277th Street (J. S. Jones and Associates, Inc., 2010).
The habitat quality appears to be poor. The source of water is Auburn Valley 6 Theaters’
parking runoff, street runoff, City of Auburn storm drainage pipelines, and runoff from
undeveloped properties. This runoff from a pollution-generating surface is untreated.
The riparian conditions are poor, particularly along South 277th Street.
Threatened and Endangered Species
Wildlife
Since the 2004 EIS was issued there have been several changes to listing status for
several species. The 2004 document identified the bald eagle as threatened. The bald
eagle was delisted in 2008 and is now a federal species of concern. The 2004 EIS did not
include several species that potentially occur within King County including: gray wolf
(federally and state endangered), grizzly bear (federally threatened and state endangered),
Canada lynx (federally and state threatened), marbled murrelet (federally and state
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
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threatened), and northern spotted owl (federally threatened and state endangered)
(USFWS 2007).
The gray wolf, grizzly bear, and Canada lynx are wide-ranging species that are found in
critically small numbers in Washington, most reliable observations are from the North
Cascades (Almack and Fitkin, 1998; WDFW, 1999). Marbled murrelets are year-round
residents on coastal waters, and they generally nest and roost in mature and old growth
forest where preferred nest sites are large flat conifer branches ranging from four to 25
inches in diameter (WDW, 1991). The northern spotted owl primarily nests and roosts in
mature/old growth coniferous forests with high canopy closure, a multi-layered, multi-
species canopy dominated by large (>30 inches diameter at breast height) trees, tree
deformities such as cavities and broken tops, large snags, woody debris, and space for
flying below the canopy (USFWS, 1990). Due to their limited range and specific habitat
requirements, the gray wolf, grizzly bear, Canada lynx, marbled murrelet, and northern
spotted owl would not be expected to occur within the urban areas of King County.
The 2004 EIS also identified several federal species of concern that may occur in King
County. The list was updated in 2007 to include: tailed frog, Larch Mountain salamander,
and northern sea otter (USFWS, 2007). The project area does not contain suitable habitat
to support these species at this time. Pacific fisher, as identified in the 2004 EIS, is no
longer listed as a species of concern in King County.
The 2004 EIS did not include the Oregon spotted frog or yellow-billed cuckoo, which are
federal candidate species. The Oregon spotted frog is endemic to the Pacific Northwest,
historically distributed in the Puget Trough Physiographic Province as well as the
Willamette Valley province and the Cascade Mountains of south-central Washington and
Oregon (McAllister and Leonard, 1997). In Washington they were historically distributed
through the lowlands of Puget Trough from the Canadian border south to Vancouver
Island and east into the southern Washington Cascades (Leonard et al., 1993; McAllister,
1995). Only four populations are extant in Washington today, one in south Puget Sound
lowlands (Mason County), one in Thurston County at Dempsey Creek, and two in the
Cascade Mountain range in south-central Washington (WDFW, 2000; McAllister and
Leonard, 1997). The spotted frog (Rana pretiosa) is nearly always found in or near
emergent wetlands within forested areas and is also associated with lakes in the prairie
landscape of the Puget Sound lowlands (Slipp, 1940). Though not typically found in
locations with a forest canopy, spotted frogs have been found in riparian areas with dense
shrub cover (McAllister and Leonard, 1997). The proposed project will impact emergent
wetlands and riparian areas; however, given the current range and distribution of the
species and the degraded conditions of on-site wetlands and stream, the likelihood of
Oregon spotted frog occurring on-site is very low.
Yellow-billed cuckoos breed in large blocks of riparian habitats (particularly woodlands
containing cottonwoods and willows) (Erhlich et al., 1988). Dense understory foliage
appears to be an important factor in nest site selection, while cottonwood trees are an
important foraging habitat in areas where the species has been studied in California (66
Federal Register 210). The available data suggest that the yellow-billed cuckoo’s range
and population numbers have declined substantially across much of the western United
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States over the past 50 years. In the Pacific Northwest, the species was formerly fairly
common locally in willow vegetation within river bottoms along the Willamette and
Columbia Rivers in Oregon; in the Puget Sound lowlands; and along the lower Columbia
River in Washington. The last confirmed breeding records were in the 1930s in
Washington and in the 1940s in Oregon. This species may now be extirpated from
Washington (66 Federal Register 210). There have been documented sightings of yellow-
billed cuckoo in King County and the Green River riparian corridor may provide some
limited foraging and breeding habitat; however, the proposed site is devoid of mature
cottonwood stands of significant size to support the species and their presence is not
anticipated.
Fish
The 2004 EIS identified the Puget Sound/Strait of Georgia coho salmon as a candidate
species; however their current federal status has been downgraded to a species of
concern. Other listing changes that have occurred since that time includes the 2007 listing
of the Puget Sound Distinct Population Segment (DPS) steelhead as threatened under the
ESA (72 Federal Register 91), and the 2005 listing of designated critical habitat for the
Puget Sound Evolutionarily Significant Unit (ESU) Chinook salmon and Coastal-Puget
Sound DPS bull trout in the Green River (70 Federal Register 170; 70 Federal Register
185).
Since the 2004 EIS, a Biological Opinion was issued by NMFS that determined the
effects of certain elements of the NFIP throughout Puget Sound is likely to jeopardize the
continued existence of the following species listed under the ESA: Puget Sound Chinook
salmon, Puget Sound steelhead, Hood Canal summer-run chum salmon, and Southern
Resident killer whales. The Biological Opinion also determined that NFIP is likely to
adversely modify the following ESA designated critical habitats: Puget Sound Chinook
salmon, Hood Canal summer-run chum salmon, and Southern Resident killer whale
critical habitats. The biological opinion provides a reasonable and prudent alternative
which can be implemented to avoid jeopardy and adverse modification of critical habitat.
In response to the Biological Opinion, FEMA developed a model ordinance for NFIP
participating communities, which includes the City of Auburn. The City of Auburn
incorporated substantive terms of the model ordinance into their interim floodplain
regulations (Ordinance No. 6295). Once FEMA approves the regulations as permanent
measures or as it may be modified in response to FEMA comments, the Auburn
regulations will become permanent. The Biological Opinion originally established a 2010
timeline for compliance for all NFIP participating communities within the Puget Sound
Basin (NMFS, 2008). On September 10, 2010, the Federal Emergency Management
Agency (FEMA) requested and was approved for a one-year extension to the September
2010 date for compliance with a Biological Opinion (BiOp) on the effects of FEMA's
National Flood Insurance Program (NFIP) on listed salmon species under the Endangered
Species Act throughout Puget Sound. Revised DFIRMs have been issued as of November
6, 2010, The new base flood elevations were published in the Federal Register on
February 16, 2011, however the required process prior to adoption of publishing notice
twice in a local newspaper and notifying local officials which begins the 90-day public
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appeal period has yet to be completed. Thus, the timing of implementation of revised
floodplain maps is uncertain.
The City of Auburn amended its floodplain regulations to implement FEMA’s draft
model ordinance (Ordinance No. 6295). This interim ordinance establishes requirements
for obtaining a permit for development in a floodplain, establishing standards to protect
structures from damage and specifying criteria to protect against habitat loss in
floodplains due to development, with emphasis on avoiding impacts to endangered
species.
Impacts
Short-Term Construction Impacts
Impacts to plants and animals would be similar to the impacts described in the 2004 Draft
EIS.
Long-Term Operational Impacts
Habitat Loss and Fragmentation
Wetland Habitat
In addition to the impacts discussed in the Draft and Final EIS, the development of
Auburn Gateway II would entail filling Wetland E. This would further reduce wetland
habitat in the project area. The expanded development area would also involve a larger
loss of upland habitat elements which may further limit access to remaining habitat by
wildlife.
Wildlife that has been listed under the ESA as endangered, threatened, species of concern
or candidate species since the 2004 EIS (i.e., grey wolf, grizzly bear, Canada lynx,
marbled murrelet, northern spotted owl, tailed frog, Larch Mountain salamander, northern
sea otter, Oregon spotted frog, yellow-billed cuckoo) are not likely to occur on-site as
described under Affected Environment. Therefore, no new impacts associated with these
species are likely to occur.
Since the 2004 EIS, wetlands in the project area have been delineated and categorized,
except for Wetland E within the Auburn Gateway II project area. Table 8 summarizes
wetland and buffer impacts associated with Auburn Gateway I and II according to the
Wetland and Stream Impact Assessment (J.S. Jones and Associates, Inc., 2010).
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Table 8. Summary of Wetland and Buffer Impacts
Wetland
Wetland Impact Area Minimum
Buffer
Width
(feet)B
Buffer Impact Area
Permanent Percent
Impacted Temporary Indirect Permanent Temporary
A 0 0 0 0 50 0.12 0
B 0 0 0 0 50C 0.10 0
C 0 0 0 0 35 C 0 0
D 0 0 0 0 50 0 0
E UnknownA 100 0 0 25 NA NA
Total Unknown 0 0 0.22 0
Source: J.S. Jones and Associates, Inc., 2010
A) Entire wetland to be filled. Since the wetland has not been delineated, the amount of wetland impact has not been
determined. Wetland E will be delineated as part of the permit submittal process.
B) Wetland buffers according to Auburn City Code 16.10.090.E.1 (City of Auburn, 2009). [RPG previously
enhanced a 35-foot buffer around the on-site portion of Wetland B and of Wetland C. This was approved by the
city and completed prior to the city’s adoption of the CAO, however, it is not anticipated that a greater buffer
standard would now apply. By the table’s listing of the city’s current buffer standards, it appears to suggest that
the city is seeking to apply a revised standard; which is not accurate. ]
C) A 35-foot enhanced buffer has been applied to Wetland B and to Wetland C and previously approved by the City.
The 2004 Draft EIS states that 0.5 acres of wetland area along South 277th Street
(Wetland ditches G, H, I and J) would be filled as a result of roadway widening. This
may no longer be the case if the ditches are not considered wetlands by any agency with
jurisdiction. See Stream Habitat below for a description of impacts to the roadside ditch
along South 277th Street.
The wetland impacts described in the 2004 Final EIS that relate to the extension of 49th
Street NE through the Stein and Port of Seattle properties and the extension of I Street
NE south of Auburn Gateway I remain accurate. Filling of Wetland E is a new impact not
described in the 2004 EIS.
The wetland buffers for Wetlands A and B would be impacted due to the proposed
alignment of I Street NE as described in the 2004 Draft EIS. The buffer areas that would
be impacted are currently a gravel road. The remaining on-site portion of the 50-foot
buffer for Wetland A would be enhanced with native vegetation. In 2005, a 35-foot buffer
for Wetland B was planted with native shrubs and trees (J.S. Jones and Associates, Inc.,
2010). Although Category II wetlands have a minimum 50-foot buffer requirement,
pursuant to ACC 16.10.090(E)(1)(b), the city’s regulations also provide that wetland
buffer widths may be averaged resulting in a reduced by up to 35 percent provided the
buffer is enhanced with native trees and shrubs and the reduction will not adversely
impact the wetland (City of Auburn, 2009).
Wetland C also has an enhanced 35-foot buffer which was planted in 2005 (J.S. Jones
and Associates, Inc., 2010). Auburn City Code now specifies a minimum 25-foot buffer
for Category III wetlands such as Wetland C (City of Auburn, 2009). The off-site
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Wetland D would likely have a minimum 50-foot enhanced buffer as required by the city
code.
Fish Habitat
Impacts on fish habitat would be associated with temporary construction impacts. As
described in the 2004 Draft EIS, erosion of exposed soils during land clearing, grubbing
and grading could occur. Sediment-laden runoff could be transported downstream to the
Green River via roadside ditches and drainages. Although this effect would be minimized
by the use of best management practices, high levels of sedimentation and low
concentrations of dissolved oxygen could alter the respiration of fish, impairing their
growth. However, impacts of this magnitude are not anticipated and wildlife should be
able to recover from any short-term impairment of water quality. The new ESA listings,
including the Puget Sound DPS steelhead, and critical habitat for the Puget Sound ESU
Chinook salmon and Coastal Puget Sound DPS bull trout would be similarly affected.
To ensure compliance with the NMFS Biological Opinion, the applicant would need to
meet FEMA and NMFS requirements for providing adequate protection to endangered
species pursuant to a city floodplain development permit.
Stream Habitat
The South 277th roadside ditch (identified in the 2004 EIS as Wetland ditches H, I and J)
located between D Street NE and the eastern boundaries of the project area would be
relocated south to make room for expanding South 277th Street. Existing vegetation
south of the roadside ditch would be removed. Expansion of the roadway is a planned
improvement by both Auburn and Kent to accommodate background increases in traffic.
The South 277th Street roadside ditch would be restored to the permitted configuration
immediately south of the road right-of-way. A planted buffer with native vegetation
would be installed on the south side of the relocated stream. The buffer width would
depend on WDFW requirements and those of other agencies with jurisdiction.
Construction of road improvements would occur within a six month time frame, during
the late spring, summer and early fall seasons when the stream channel is dry (J.S. Jones
and Associates, Inc., 2010).
Relocation of the South 277th Street roadside ditch and development of Auburn Gateway
I and II would result in an improvement in stream habitat functions which are currently in
poor condition. The width of the buffer on the south side of the roadside ditch would
likely increase from the existing 10-foot buffer. After buffer enhancement invasive plants
would be removed from the roadside ditch buffer during the required 10-year
maintenance period. The storm water system installed for the Auburn Gateway I and II
project would provide some improvements to water quality. One culvert at the
intersection of G Street NE and South 277th Street would be removed. The culvert at the
intersection of I Street NE and South 277th Street would be replaced with a fish passable
culvert as required by WDFW (J.S. Jones and Associates, Inc., 2010).
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The portion of the ditch along South 277th Street between D Street and Auburn Way
North would be piped (identified in the 2004 EIS as Wetland Ditch G). This ditch is
expected to be considered a Water of the U.S by the COE. This section of the ditch
conveys water across the site to the downstream system. Roadway widening would
impact 8,040 square feet of Waters of the U.S. (J.S. Jones and Associates, Inc., 2010).
As stated in the 2004 DEIS, roadside ditches can provide some minimal shelter, food, and
nesting sites. Also, ditches typically are used to a greater extent by birds and mammals
than adjacent agricultural fields. Piping the ditch along South 277th Street between D
Street and Auburn Way North would result in permanent impacts to roadside ditch
habitat. Relocating the South 277th roadside ditch would result in temporary impacts to
roadside ditch habitat during construction.
No permanent impacts to the east side stream (identified in the 2004 EIS as Wetland
Ditch K) are proposed. The east side stream is almost entirely outside of the Auburn
Gateway I and II project and is entirely outside of the footprint of the proposed I Street
extension area. As noted in the 2004 EIS, the extension of 49th Street NE through the
Stein and Port of Seattle properties would impact the stream. Such impacts could impact
fish passage unless designed properly to avoid blocking passage.
Mitigation
The 2004 Draft EIS on pages 143-145 provided a list of mitigation measures to mitigate
impacts both during construction and operation of the planning area. Several mitigation
measures no longer apply since the EIS was prepared. The following provides a list of
new mitigation measures that are recommended for impacts on plants and animals as a
result of the proposed Auburn Gateway I and II development. These mitigation measures
replace the mitigation measures provided in the Draft EIS but are very similar.
This section discusses the general mitigation measures for impacts due to both
construction and long-term operations that apply to development under the Northeast
Auburn/Robertson Properties Special Area Plan, including the Auburn Gateway project.
As noted above, the project must comply with local, state, and federal regulations that
protect wildlife habitat in various ways. This section begins with mitigation required by
law for impacts that may occur as a result of the project. The discussion of regulations
that provide assurance of mitigation is followed by additional recommendations for
mitigation that should be employed by the City and RPG in conjunction with
implementation of the project.
The Federal Clean Water Act (CWA) Section 404 requires mitigation for impacts on
Waters of the U.S. For any impacts anticipated, the design and construction of the
Northeast Auburn/Robertson Properties Special Area Plan project must follow the
mitigation sequence developed by the Corps for waters of the United States:
1. Avoid impacts on wetland, stream, and wildlife habitats and associated species
and their associated species
2. Minimize impacts, if avoidance is not possible
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3. Rectify and restore areas where possible
4. Reduce the adverse impacts by preservation and maintenance operations
5. Provide compensatory mitigation (i.e., replacement of lost wetlands)
6. Monitor the impacts and mitigation and take appropriate corrective measures.
The COE generally requires a 1 to 1.25 replacement of wetlands that are proposed to be
filled and may also allow mitigation through wetland enhancement at a 1:3 ratio.
An Hydraulic Project Approval (HPA) may be required for potential impacts on Auburn
Creek (Stream Number 0056 located along 86th Avenue South), which drains from the
project area to the Green River, and the roadside ditch along the south side of South
277th Street. WDFW typically issues an HPA on the condition that approved mitigation
measures, determined on a case-by-case basis, and best management practices will be
implemented during and after the construction of the project.
Impacts on water quality are regulated by the City’s stormwater regulations, as discussed
in the Water Resources section of the 2004 EIS.
The proposed Auburn Gateway Design Guidelines indicate that native plantings would be
used in wetland buffer areas and around detention facilities (BCRA 2003). The guidelines
also indicate that trees and other landscaping would be used in the parking areas, around
loading areas and in building setbacks, and along public roadways within the Auburn
Gateway project area.
The following mitigation measures are recommended for impacts on plants and animals:
• Prepare a wetland mitigation plan meeting applicable requirements for mitigating
potential impacts. The plan should:
o Coordinate wetland mitigation conservation requirements of the various
agencies with regulatory authority.
o Coordinate wetland mitigation conservation with phasing of earthwork and
construction to avoid/reduce reoccurrence of disturbance or impacts.
o Include information on measures to be employed to avoid impacts on wetland
hydrology, as discussed in the Water Resources section of the 2004 Draft EIS.
o Stipulate mitigation measures for wetlands affected by dredging or filling in
accordance with Auburn City Code Chapter 16.10. Mitigation could be
implemented by on-site or off-site wetland enhancement or creation consistent
with local, state and federal regulations.
o Provide buffers of at least 75 feet standard width for all emergent wetlands
(except the wetland ditches along South 277th Street), and buffers of 100 feet
average for all forested scrub-shrub wetlands. Buffer averaging could be
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allowed provided that the minimum buffer is no less than 65 percent (a 35
percent reduction) of the specified buffer width.
o Provide a mitigation plan for approval by regulating agencies for the planting
or enhancement of wetland buffers with native plant species as soon as
possible after initial site grading is completed.
o Minimize the clearing of native vegetation and protect remaining onsite
vegetation from damage during construction.
o Identify the construction boundaries and methods to be employed after
completion of project to avoid encroachment on adjacent habitat areas.
o Schedule construction within work windows specified by WDFW, the COE,
NOAA Fisheries, and/or the USFWS to avoid critical periods (i.e., wintering,
nesting and breeding/spawning, and migration) for species of concern listed as
present or potentially present in the planning area.
o Provide a stormwater pollution prevention plan (SWPPP) that will prevent or
minimize sedimentation and potential hazardous spills that could affect both
the onsite and offsite water bodies.
o Minimize night lighting near wetlands during construction.
o Identify locations and types of night lighting to be used for development that
minimizes light impacts on wetland habitats and buffers.
o Establish a protocol for wetland and hydrologic monitoring to ensure that
wetland mitigation and newly planted wetland buffers are thriving after the
installation of the plantings is completed. Provide financial security to
guarantee monitoring, maintenance and contingency measures.
o Wetland monitoring should continue annually for a minimum of 5 years after
the project is completed, and should include observations and reporting of
native vegetation and hydrologic conditions that may be adversely affected by
fill adjacent to wetland areas.
o Replace the culvert at the intersection of I Street NE and South 277th Street
with a fish passable culvert.
• Using innovative designs, protect wetlands and wetland buffers from the intrusion
of humans and domestic animals by means of barriers to humans and domestic
animals, while still allowing aesthetic enjoyment of these areas.
• Require modifications to stormwater and/or groundwater management if adverse
effects on wetland hydrology are observed before the end of the wetland
monitoring period.
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• Revegetate portions of the project area that are disturbed only for construction
purposes (e.g., areas surrounding buildings or construction staging areas) as soon
as possible after construction is completed. Establish a protocol for and conduct
monitoring to ensure that newly planted areas are thriving. Provide financial
security to guarantee monitoring, maintenance and contingency measures.
• The construction staging areas should be located on the existing gravel within the
drive-in theater so wildlife displacement is delayed.
A number of conservation measures are recommended to avoid or minimize potential
impacts to streams (including South 277th Street roadside ditch) during construction.
• There should be no loss of stream length as a result of relocating the existing
stream channel.
• In-water construction activities will be regulated by the HPA issued for the
project. The anticipated in-water work should occur from July 1 to August 31, or
when the water bodies in the project area are dry. This will limit work within the
wetted perimeter of the water bodies to the low-flow summer months and reduce
potential for impacts to fish species.
• Staging areas, stockpiles, equipment storage areas, and other similar facilities
should be set back at least 100 feet from the top-of-bank of the stream.
• To minimize the effect of dewatering the work area on fish species, the HPA for
this project will require that the project proponent capture and safely remove fish
and other aquatic life from the portion of stream to be abandoned. Captured fish
are required to be immediately and safely transferred to free-flowing water
downstream of the bypass following methods outlined in the anticipated HPA for
this project.
• The project proponent should seek assistance from WDFW to remove fish prior to
construction if WDFW personnel are available. If WDFW personnel are not
available, the project proponent should arrange for the removal of fish by a
qualified fisheries biologist.
• The amount of area that is cleared and graded at any one time should be limited,
and construction activities should be scheduled soon after an area has been
cleared and stripped of vegetation.
• Construction areas and limits of work should be clearly identified in the field and
on plans to minimize habitat disruption.
• A temporary erosion and sediment control (TESC) plan and site-specific BMPs
should be implemented as directed by the project engineer in accordance with the
City’s standard specifications for erosion control and standard HPA provisions.
Site-specific BMPs will include at a minimum:
o Washout of construction vehicles, vehicle maintenance, and refueling should
be prohibited within 100 feet of the top-of-bank of the stream; and
o Construction equipment should be outfitted with emergency spill kits and
construction crews should be trained in their proper use.
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• All disturbed areas should be stabilized to prevent erosion within seven days of
the completion of the project.
• Where possible, native vegetation removed during construction should be
replaced with native tree and shrub species following construction. These actions
will increase the water quality, hydrologic, and habitat features associated with
these areas.
• Stream buffers should be established and planted with a mixture of native tree and
shrub species. Establish a protocol for stream mitigation monitoring to ensure
that stream mitigation and newly planted buffers are thriving after the installation
of the plantings is completed. Provide financial security to guarantee monitoring,
maintenance and contingency measures.
• In stream habitat features such as large woody debris (LWD) and boulders, should
be incorporated into final design to increase habitat complexity and provide cover
for fish species. The performance of habitat features should be monitored and
reported.
• Relocated stream reaches should include fine grading necessary to establish
complex habitat types including pool and riffle complexes, which may require the
installation of grade control structures. The performance of habitat features and
grade control structures should be monitored and reported.
• The relocated portion of streambed should allow for placement of spawning sized
gravel at a minimum depth of six inches.
• The culvert at the intersection of I Street NE and South 277th Street would be
replaced with a fish passable culvert (J.S. Jones and Associates, Inc., 2010).
• To ensure compliance with the NMFS Biological Opinion, the applicant would
need to meet FEMA and NMFS requirements for providing adequate protection to
endangered species pursuant to a city floodplain development permit for an
alteration within regulatory floodplain.
Significant Unavoidable Adverse Impacts
In addition to the impacts described in the 2004 Draft EIS, Auburn Gateway II would
result in minor loss of wetland functions that would be replaced by mitigation meeting
federal, state and local requirements. Although some fragmentation of wetland habitat is
unavoidable with filling of the wetlands, the wetland habitat functions on the Auburn
Gateway II site are minimal and can be replaced through mitigation measures. As such,
no significant impacts to wetland functions are expected.
Impacts on ESA listed species and habitats could occur during construction are not likely.
If at any time they become more likely, such as if flooding brings fish onto the site, the
impacts could be minimized by employing conservation measures established through
meeting FEMA and NMFS requirements for providing adequate protection to endangered
species. With appropriate measures, no significant impacts are expected.
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Transportation
The analysis below is summarized from Auburn Gateway Transportation Impact Analysis
(TIA) prepared by Transportation Solutions, Inc, in August 2011. The TIA is attached to
this addendum and hereby incorporated into the EIS. The traffic analysis focuses on the
applicant’s preferred land use of Alternative 2 (evaluated in the 2004 EIS as 720,000
square feet of retail development) modified to include Auburn Gateway II and to evaluate
an optional roadway layout as described in the preceding Project Background.
While the all retail alternative is expected to be the most likely use for the site, in order to
maintain the applicant’s development flexibility the worst case development condition for
traffic under any of the development alternatives is also studied. Of the three alternative
land use options evaluated in the 2004 EIS, the Office/Retail Option (Alternative 1) was
found to be the most intensive from a transportation perspective. The Office/Retail
Option includes 1,600,000 square feet of office with 200,000 square feet of retail
development. Thus, both land use alternatives are considered.
Because the trip generation of Alternative 3 evaluated in the 2004 EIS (the Residential/
Retail Option) would be less than either Alternative 1 and Alternative 2, it was not re-
analyzed for this addendum. The Residential/ Retail Option would have characteristics
that are similar to but proportionately less than either of the land use options examined in
this addendum with the added land assemblage.
The transportation impact analysis for this addendum also assumed development of the
site would occur in two phases, with the North Phase located north of 49th Street NE and
the South Phase located south of 49th Street NE. Because office development would
likely include various density levels, it was assumed that 60% of the Full-build
Office/Retail Option could occur on either the north portion of the site or the south
portion of the site depending on possible development conditions at the time. Therefore
the trip generation within a single phase was never assumed to exceed 60 percent of the
cumulative trip generation predicted for the entire project. Accordingly, the following
development conditions were evaluated:
Retail Only option
• South Phase (approximately 236,000 square feet retail space) first;
• North Phase (approximately 484,000 square feet retail space) first;
• North and South Phases together (720,000 square feet retail space); and
Office Retail Option
• South Phase with 60% of the office/retail development first; (60% of trip
generation)
• North Phase with 60% of the office/retail development first; (60% of trip
generation)
• Full development with 60% of the office/retail in the southerly portion of the
property; (60% of trip generation)
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• Full development with 60% of the office/retail in the northerly portion of the
property; (60% of trip generation)
Affected Environment
Consistent with the 2004 EIS, development related traffic impacts were evaluated under
year 2020 traffic conditions. Year 2020 traffic forecasts without the development were
refined to reflect actual traffic patterns and recent historical growth trends. Based on this
approach, corridor volumes in 2020 were found to be very similar to those forecast in the
2004 EIS. Directional road segment and intersection turning movement volumes in this
current analysis differed somewhat from the 2004 EIS but more realistically reflect land
use patterns. Background levels of service were found to be improved in this analysis as
compared with the 2004 EIS analysis due to the use of refined directional split and
turning movement allocations from traffic modeling refinements.
One change in the study area that has occurred since the EIS is the Trail Run residential
subdivision and planned unit development (PUD) (also formerly known as River Sands)
east of the project area, including opening of L Street NE to provide access to that site
onto South 277th Street. In the EIS, access to Trail Run was expected to be via a
roadway that would have right-in/right-out only access to South 277th Street, and that
49th Street NE would be extended as a two-lane local road east of I Street NE to connect
and serve the Trail Run development. On an interim basis, a temporary signal was
installed at L Street NE and South 277th ST and monies were collected by the City for the
future extension of 49th Street NE east of I Street NE and for I ST NE to serve the Trail
Run development and to facilitate the relocation of the temporary signal to the future
intersection of I Street NE and South 277th ST. New in this analysis is an assessment of
conditions with and without the 49th Street NE extension east of I Street NE to Trail Run
and this analysis considers more than one traffic signal on South 277th ST to evaluate
transportation options.
Impacts
Under this traffic analysis, Auburn Gateway is proposed to be a retail commercial mixed
use development that could be developed in two phases – one south of 49th Street NE and
one north of 49th Street NE or all together. The zoning established for the Auburn
Gateway properties would allow for a mix of residential, office and other retail uses.
Adjacent property (Auburn Gateway II) has been added to the original project but the
developable floor area maximums remain the same as evaluated in the 2004 EIS. The
sequence of development is currently unknown so the combinations of the two-phase
development were analyzed.
Roads adjacent to each development phase are planned to be constructed concurrently so
they would be in place when that phase of development is occupied. For a complete
description of the assumed roadways and turning movements assumed, see the TIA
(2011). The only proposed changes in the road network from the 2004 EIS are at D Street
NE north of 49th Street NE and 49th Street NE east of I Street NE being reviewed as a
stub end road. D Street NE is proposed to be vacated (subject to a future city council
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
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decision) and become an internal circulation aisle in the parking lot of the project.
Consistent with the 2004 EIS, D Street NE at Auburn Way North would be closed with a
cul-de-sac. As discussed above, the analysis also looked at conditions with and without
the 49th Street NE connector, east of I Street NE.
The roadway improvements that were assumed would be developed include the
following:
• Widen S 277th Street from 3 lanes to 5 lanes east of Auburn Way N to L Street
NE. At the intersection with I Street NE there is likely the need for a 6 to 7 lane
wide section including a dual westbound left turn lane. The majority of widening
would occur on the south side of the road.
• At S 277th Street/ Auburn Way N:
o Eastbound: add one through lane and a right-turn lane
o Westbound: add one through lane and a right-turn lane
o Northbound: add a northbound to eastbound ‘add lane’
• Extend I Street NE from 45th Street NE to S 277th Street. I Street NE will be a 5
lane cross-section with the possibility of an additional northbound right turn lane
(Construct the north sections during North Phase and Full-Build development
conditions)
• Construct S 277th Street/ I Street NE intersection with a traffic signal (during
North Phase and Full-Build development conditions):
o Eastbound: 3 through lanes and 1 right-turn lane
o Westbound: 2 through lanes and 2 left-turn lanes
o Northbound: 1 left-turn lane, one right/left shared turn lane and one exclusive
right turn lane
• Widen 49th Street NE east of Auburn Way N to I Street NE with a 3-lane minor
arterial standard.
• Install a new traffic signal at 49th Street NE/ Auburn Way North to include left-
turn pockets on 49th Street NE.
• Construct a traffic signal at the South Phase access off Auburn Way N. The new
signal would include separate right-turn and left-turn approaches from the
development site. (During the South Phase development condition or at Full-
Build development conditions when conditions warrant).
• Close and cul-de-sac the intersection of D Street NE at Auburn Way N
• Construct a traffic signal at I Street NE and 49th Street NE when warranted
• Construct a traffic signal at 45th Street NE and Auburn Way North when
warranted
• Construct a traffic signal at I Street NE and 45th Street NE when warranted
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All road improvements would include curb, gutter, sidewalks, street lighting, landscaping
and storm drainage provisions except for S 277th Street which would include an all-
weather path integrated in the landscape site frontage buffer area. In addition to
completing road and utility improvements to adjacent roadways under the City’s half-
street regulations, Robertson Properties Group proposes to work with the City through a
Development Agreement to construct several major road improvements in the immediate
vicinity of the development. The Development Agreement states that some road and
utility improvements may be eligible for financial assistance from the City for traffic
impact fee credits, mitigation fees collected for other developments in the area and
payback mechanisms. See the Transportation Mitigation section for a table regarding
roadway improvements and phasing.
Trip generation was forecast used the same methodology as used in the 2004 EIS. The
PM peak hour trip generation is therefore forecast to be 2,419 PM peak hour trips for
Alternative 1 and 1,803 PM peak hour trips Alternative 2. For this analysis, the driveway
or primary trips include diverted-link trips.
Thus, for the phasing options analyzed, the level of service will remain at or under the
levels forecasted for Full-build for either the Retail Only or Office/Retail Options.
These development-generated trips were assigned to the road network for each phase and
for full development. Refinements to road channelization were developed and level of
service was computed. To evaluate the effect of development phasing, LOS tables of the
various phasing options for each alternative were prepared. Under either land use
alternative, the LOS associated with any of the phases would be better than the LOS with
Full-build development. Levels of service with each phase of development were
generally found to operate equal to or better than the level of service disclosed in the
2004 EIS. A comprehensive LOS summary under each of the various conditions
analyzed is presented in Tables 9 and 10.
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
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Table 9. 2020 Office/Retail; PM Peak Hour Level of Service
Intersection No-Build 2004 EIS Full Build South Phase North Phase
Control LOS Delay Control LOS Delay Control LOS Delay Control LOS Delay
277th
St/AWN
S E 76.0 S F 84.6 S E 63.4 S E 58.9
277th St/D St U F 533.3 U E 39.3 U C 18.1 U C 15.5
277th St/I St S E 73.4 S B 15.7
277th St/L St S A 4.3 S A 6.1 U B 10.1
49th St/AWN U E 30.3 S C 20.6 S B 19.6 S B 13.0
49th St/D St U B 14.4 U B 13.3 U B 11.6
49th St/I St S D 36.6 S C 30.4
Access/AWN S B 12.5 U D 31.3
45th St/AWN U D 24.4 S B 19.0 U D 29.1 U C 22.4
45th St/I St S B 13.7 U B 11.9
Intersection
Full-Build (South 1st) Full-Build (North 1st) Full-Build (South 1st)
45th/AWN Signal
Full-Build (North 1st)
45th/AWN Signal
Control LOS Delay Control LOS Delay Control LOS Delay Control LOS Delay
277th
St/AWN
S E 63.6 S E 63.7 S E 63.2 S E 63.9
277th St/D St U C 16.9 U C 16.9 U C 16.9 U C 16.9
277th St/I St S C 22.1 S C 23.7 S C 22.2 S C 23.1
277th St/L St U B 10.7 U B 10.7 U B 10.7 U B 10.7
49th St/AWN S B 18.4 S B 18.6 S B 12.6 S B 13.6
49th St/D St U B 13.7 U B 14.1 U B 12.0 U B 14.1
49th St/I St S
R
C
C
27.6
24.0
S
R
C
C
27.8
18.4
S
R
C
C
27.7
24.0
S
R
C
C
29.6
18.4
Access/AWN U D 31.0 U D 26.0 U B 10.3 U A 9.9
45th St/AWN U D 25.2 U C 25.0 S B 11.9 S A 7.8
45th St/I St U B 13.7 U B 13.7 U C 15.3 U C 15.4
Intersection
Full-Build (South 1st)
I St & L St Signals
Full-Build (North 1st)
I St & L St Signals
Control LOS Delay Control LOS Delay
277th
St/AWN
S E 64.0 S E 64.0
277th St/D St U C 16.9 U C 16.9
277th St/I St S C 20.8 S C 21.8
277th St/L St S A 3.4 S A 2.9
49th St/AWN S B 18.3 S B 18.4
49th St/D St U B 13.7 U B 14.0
49th St/I St S
R
B
C
13.2
21.8
S
R
B
C
13.0
21.8
Access/AWN U D 31.0 U D 26.0
45th St/AWN U D 25.2 U C 24.7
45th St/I St U B 13.7 U B 13.7
Control = Intersection control (U = unsignalized; S = signal; R = roundabout)
Delay = expressed in seconds of control delay
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
48 November 2011
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Table 10. 2020 Retail Only; PM Peak Hour Level of Service
Intersection No-Build 2004 EIS Full-Build South Phase North Phase
Control LOS Delay Control LOS Delay Control LOS Delay Control LOS Delay
277th St/AWN S E 76.0 S E 76.9 S D 53.4 S E 61.2
277th St/D St U F 533.3 U E 41.6 U B 12.5 U B 14.9
277th St/I St S E 62.7 S B 14.6
277th St/L St S A 4.3 S A 5.2 U A 9.8
49th St/AWN U E 30.3 S B 19.1 S B 15.0 S B 11.0
49th St/D St U B 12.7 U B 10.5 U B 12.0
49th St/I St S B 15.6 S C 27.9
Access/AWN
45th St/AWN S B 11.6 U C 29.8
45th St/I St U D 24.4 S B 18.4 U D 26.2 U C 23.0
Intersection
Full-Build Full-Build
45th/AWN Signal
Full-Build
I St & L St Signals
Control LOS Delay Control LOS Delay Control LOS Delay
277th St/AWN S E 64.9 S E 64.3 S E 65.5
277th St/D St U C 15.6 U C 15.6 U C 15.6
277th St/I St S B 17.7 S B 19.5 S B 18.4
277th St/L St U B 10.1 U B 10.2 S A 3.9
49th St/AWN S B 16.6 S B 12.4 S B 17.1
49th St/D St U B 14.4 U B 12.9 U B 14.3
49th St/I St S
R
C
B
29.1
10.5
S
R
C
B
27.4
10.5
S
R
A
A
8.5
10.0
Access/AWN U C 23.5 U A 9.5 U C 23.5
45th St/AWN U C 24.9 S A 8.7 U C 24.9
45th St/I St U B 11.8 U B 14.4 U B 11.9
Control = Intersection control (U = unsignalized; S = signal; R = roundabout)
Delay = expressed in seconds of control delay
A queuing analysis was performed to analyze stacking, or queuing, between signalized
intersections. This analysis forecasts no intersection queuing issues that cannot be
mitigated.
The TIA evaluated traffic operations if the South Phase site access were signalized at
Auburn Way North. Under this condition 45th and 49th Streets NE would also be
signalized. Overall study intersection operations with a signal at the South Phase site
access were projected to be similar to those under the other Full-Build conditions without
the South Phase site access signalized. Vehicle queues are not projected to extend to
adjacent intersections, suggesting that the presence of three new signals on Auburn Way
North at 49th Street NE, the South Phase site access, and 45th Street NE could operate
sufficiently, when warranted by the prevailing traffic volumes. In other words, queues on
Auburn Way North would not interfere with traffic operations at the next adjacent
signalized intersection.
The TIA analyzed the S 277th Street/ I Street NE intersection if the intersection were not
improved to a “flying T”. Intersection channelization is as follows: 3 eastbound through
lanes, 1 eastbound right-turn lane, 2 westbound left-turn lanes, 2 westbound through
lanes, 1 dedicated northbound left-turn lane, 1 dedicated northbound right-turn lane, and
1 shared northbound left-turn-right-turn lane. The westbound through movement would
be signal controlled instead of free flowing. This intersection scenario may be warranted
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
November 2011 49
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if the “flying T” proposal is not feasible. Intersection level of service would acceptable if
the 227th Street/ I Street NE intersection is a standard intersection. Level of service is
similar and comparable to conditions if the intersection were a “Flying T”. Westbound
queues increase from “Flying T” conditions, but are not anticipated to spillback to L
Street. Northbound queues would increase up to 50% of the segment length on I Street
NE between S 277th Street and 49th Street NE. Signal timing may need to be adjusted and
storage capacities for the northbound approach will need to be amended if the standard
intersection approach is selected verses the “Flying T”.
The analysis found that two signals on South 277th Street (at I Street NE and at L Street
NE) can generally operate safely and effectively with or without the two-lane 49th Street
NE connector that was originally envisioned to connect the Auburn Gateway with Trail
Run development. This was true of both the Retail Only and the Office/Retail options at
full buildout.
The traffic report also examined the impacts of allowing the applicant to construct a
signal at the SW access drive at Auburn Way North. The analysis shows with the signal
at the SW access, northbound vehicles on Auburn Way North would be delayed by
approximately 12 seconds compared to conditions without a signal. Without a signal, the
driveway could have safety issues similar to those that currently exist at the intersection
of D Street NE and Auburn Way N.
Mitigation
Traffic related mitigation recommended for the project is substantially the same as that
described in the EIS, with some refinements and minor changes based on a more refined
development program, project phasing, and traffic forecasts.
The City of Auburn has three programmed improvement projects: I Street NE Corridor
between 40th Street NE and S 277th Street; S 277th Street between Auburn Way N and
Green River; and 49th Street NE between Auburn Way N and M Street NE. All three
improvement projects are triggered by the development of Auburn Gateway although
other, non-Auburn Gateway traffic will use these facilities to avoid congestion on
existing roads.
All intersections would operate at or better than the levels forecast in the 2004 EIS. All
intersections except for Auburn Way North/ S 277th Street (South Phase Office/ Retail
Option only) are forecast operate at or above the City’s adopted LOS Standard (LOS D or
better) under each phase or full-build-out development condition. Possible mitigation of
this below standard condition can be met by constructing I Street NE as part of the South
Phase Office Option, reduce the size or revise the sequence of development phasing of
the South Phase Office/Retail Option, or employ a Transportation Management Program
(TMP) to reduce trip making.
This section outlines the roadway and intersection improvements incorporated into the
traffic model(s) used to evaluate the development. Unless otherwise noted below, the
following roadway improvements listed below were incorporated in the area-wide
alternatives:
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
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• Widen S 277th Street from 3 lanes to 5 lanes east of Auburn Way N to L Street
NE. At the intersection with I Street NE there is likely the need for a 6 to 7 lane
wide section including a dual westbound left turn lane. The majority of widening
would occur on the south side of the road.
• At S 277th Street/ Auburn Way N:
o Eastbound: add one through lane and a right-turn lane
o Westbound: add one through lane and a right-turn lane
o Northbound: add a northbound to eastbound ‘add lane’
• Extend I Street NE from 45th Street NE to S 277th Street. I Street NE will be a 5
lane cross-section With the possibility of an additional northbound right turn lane
(Construct the north sections during North Phase and Full-Build development
conditions)
• Construct S 277th Street/ I Street NE intersection with a traffic signal (during
North Phase and Full-Build development conditions):
o Eastbound: 3 through lanes and 1 right-turn lane
o Westbound: 2 through lanes and 2 left-turn lanes
o Northbound: 1 left-turn lane, one right/left shared turn lane and one exclusive
right turn lane
• Widen 49th Street NE east of Auburn Way N to I Street NE with a 3-lane minor
arterial standard.
• Install a new traffic signal at 49th Street NE/ Auburn Way North to include left-
turn pockets on 49th Street NE.
• Construct a traffic signal at the South Phase access off Auburn Way N. The new
signal would include separate right-turn and left-turn approaches from the
development site. (During the South Phase development condition or at Full-
Build development conditions when conditions warrant).
• Close and cul-de-sac the intersection of D Street NE at Auburn Way N
• Construct a traffic signal at I Street NE and 49th Street NE when warranted
• Construct a traffic signal at 45th Street NE and Auburn Way North when
warranted
• Construct a traffic signal at I Street NE and 45th Street NE when warranted
All road improvements would include curb, gutter, sidewalks, and landscaping except for
S 277th Street that would include an all-weather path integrated in the landscape site
frontage buffer area. These and other offsite improvements for both of the land use
options are summarized in Table 12 below. This table compares all mitigation found in
the 2004 EIS with the mitigation required for the current proposals. The mitigation does
not change from the 2004 EIS except for the following:
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
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• D Street between 49th Street and S 277th Street is proposed to be vacated since
RPG owns most of the properties on both sides of the street; this corridor can
better serve as an internal circulation aisle; and this street will no longer be a
through street to the south where a cul-de-sac is proposed to eliminate an existing
safety problem. RPG will work with others along the frontage to provide access
via a private easement.
• I Street NE will be phased so the north portion of the road (49th Street NE to S
277th Street) will only be constructed with the North Phase of site development.
With these and other area wide improvements all intersections operate at or better than
the levels forecast in the 2004 EIS. All intersections except for Auburn Way North/ S
277th Street (South Phase Office/ Retail Option only) are forecast operate at or above the
City’s adopted LOS Standard (LOS D or better) under each phase or full-build-out
development condition. Possible mitigation of this below standard condition can be met
by constructing I Street as part of the South Phase Office Option, reduce the size or revise
the sequence of development phasing of the South Phase Office/Retail Option, or employ
a Transportation Demand Management Program (TDMP) to reduce trip making. In the
event one or a combination of these options is not determined to be viable, the city has
the authority to designate an intersections as categorically exempt from the level of
service standard if the intersection has been expanded to the practical maximum that the
benefits of increasing capacity are offset by other economic, environmental and/or public
safety considerations.
Similar to the 2004 FEIS, Table 11 also shows the percentage of development –generated
trips at full development for the Retail and Office/Retail Options. However, note that in
some cases percentages of project generated trips are not directly applicable to
determining proportionate share of a project. In the case of the Site Access Signal, for
example, the need for the signal would not exist had it not been for the development’s
desire to have a signalized access. The signal serves no purpose on Auburn Way North
otherwise and actually impedes regional traffic flow on Auburn Way North The
methodology for estimating the development related portion of traffic volume associated
with the Retail Only and Office/Retail Options is simply the ratio of the net new
development-generated volumes (at full development) divided by the total 2020 volumes
with full development. A more detailed description of the derivation and data sources for
the ‘Development Trip Portion’ is provided in the TIA, Appendix D.
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
52 November 2011
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Table 11. Road Mitigation Summary
Location 2004 EIS
EIS Addendum 2020 Volumes PM Peak Hour
Retail Only Option Office/Retail Option
No-Build,
Full road
Network1
Retail Only
Option
(Office/Retail
Option) 2
Development
Trip Portion
On Site or Adjacent to the Site
I Street NE (S 277th to 49th Street NE) –
5 lane minor arterial w/auxiliary right-
turn lanes
Concurrent with Robertson
Development
Concurrent with North Phase or
Full-build Development
Concurrent with North Phase or
Full-build Development
687 1,398
(1,670)
51%
(59%)
I Street NE (49th Street NE to 45th
Street NE) – 5 lane minor arterial
w/auxiliary right-turn lanes
Concurrent with Robertson
Development
Concurrent with South Phase or
Full-build Development
Concurrent with South Phase or
Full-build Development
599 1,087
(1,290)
45%
(54%)
49th Street NE (I Street NE to Auburn
Way N) – 3 lane minor arterial
Concurrent with Robertson
Development
Concurrent with Initial Phase of
Development
Concurrent with Initial Phase of
Development
189 562
(682)
66%
(72%)
S 277th Street (W boundary to E
boundary) – 5 lane major arterial
w/auxiliary right-turn lanes
Concurrent with Robertson
Development
Concurrent with North Phase or
Full-build Development
Concurrent with North Phase or
Full-build Development
3,324 3,798
(3,960)
12%
(16%)
S 277th Street (Auburn Way North to D
Street) – widen to a 5 lane cross-section
None Concurrent with South Phase or
Full-build Development
Concurrent with South Phase or
Full-build Development
3,324 3,798
(3,960)
12%
(16%)
S 277th Street (D Street to L D Street) –
widen to a 4 lane cross-section
None Concurrent with South Phase or
Full-build Development
Concurrent with South Phase or
Full-build Development
3,324 3,798
(3,960)
12%
(16%)
I Street NE at S 277th Street – Signalize
w/dual westbound left-turn lane
Concurrent with Robertson
Development
Concurrent with North Phase or
Full-build Development
Concurrent with North Phase or
Full-build Development
3,746 4,672
(4,964)
20%
(25%)
I Street NE at 49th Street NE –
(Roundabout or Signal)
Concurrent with Robertson
Development (when warrants
are met)
Roundabout with initial phase or
signalization concurrent with Full
Development (when warrants are
met)
Roundabout with initial phase or
signalization concurrent with Full
Development (when warrants are
met)
710 1,403
(1,759)
49%
(60%)
49th Street NE at Auburn Way N –
Signalize
Concurrent with Robertson
Development
Concurrent with Initial Phase of
Development
Concurrent with Initial Phase of
Development
2,473 2,884
(2,952)
14%
(16%)
D Street 49th Street NE to S 277th Street
– Three lane minor arterial
Concurrent with Robertson
Development
Vacate Street concurrent with site
development
Vacate Street concurrent with site
development
177 302
(292)
41
(39%)
D Street 49th Street NE to Auburn Way
North – 3 lane minor arterial
Nothing Cul-de-sac southerly terminus at
Auburn Way North Concurrent
with initial phase of Development
Cul-de-sac southerly terminus at
Auburn Way North Concurrent
with initial phase of Development
32 86
(66)
63%
(51%)
Site Access at Auburn Way N – Signal
3
If warranted When warranted after the 45th
Street NE/ Auburn Way North
signal is warranted
When warranted after the 45th
Street NE/ Auburn Way North
signal is warranted
2,386 2,836
(2,985)
16%
(20%)
1. No-Build Full Network Volumes represent the future without development conditions with the future road network complete (i.e. I Street NE extended between S 277th Street and 45th Street NE)
2. Retail (Office) represents the 2020 Full Build Retail Only and Office/Retail Volumes with a Signal at 45th Street NE/ Auburn Way NE conditions
3. This improvement includes 2020 Full Build Volumes with a signal at the South Phase site access
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
November 2011 53
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Table 11. Road Mitigation Summary (Continued)
Location 2004 EIS
EIS Addendum 2020 Volumes PM Peak Hour
Retail Only Option Office/Retail Option
No-Build
Full Street
Network 1
Retail Only
Option
(Office/Retail
Option) 2
Development
Trip Portion
Off Site
Auburn Way N / S 277th Street (City of
Auburn) - Add westbound right-turn
lane
Include in plans for widening
S 277th Street between Auburn
Way N and Green River.
Concurrent with S 277th Street
improvements under the North
Phase and Full-Build conditions.
Will likely require additional right
of way.
Concurrent with S 277th Street
improvements under the North
Phase and Full-Build conditions.
Will likely require additional right
of way.
5,409 5,988
(6,195)
10%
(13%)
Auburn Way N / 37th Street NE (City
of Auburn) – Add southbound right-
turn lane or eastbound right-turn lane
Construct improvement. Contribute proportionate share
when City includes it on its TIP
and acquires right of way
Contribute proportionate share
when City includes it on its TIP
and acquires right of way
3,890 4,111
(4,226)
5%
(8%)
Harvey Road NE / Eighth Street NE
(City of Auburn) – Widen southeast-
bound Harvey Road NE to two lanes.
Include in City plans for
widening Harvey Road NE.
Included in City plans for
widening Harvey Road NE. Share
paid through Traffic Impact Fees.
Included in City plans for
widening Harvey Road NE. Share
paid through Traffic Impact Fees.
5,036 5,137
(5,217)
2%
(3%)
Central Avenue / S 259th Street (City of
Kent) – Add northbound right-turn lane
Contribute proportional share. Contribute proportionate share
when City includes it on its TIP
and acquires right of way
Contribute proportionate share
when City includes it on its TIP
and acquires right of way
4,279 4,442
(4,527)
4%
(5%)
S 277th Street / 55th Ave S (City of
Kent/King County) – Change
westbound S 277th Street to a dual left-
turn lane and one through lane. Widen
55th Street with dual left turns.
Contribute proportional share. Contribute proportionate share
when City includes project on its
TIP and acquires right of way
Contribute proportionate share
when City includes project on its
TIP and acquires right of way
2,895 2,995
(3,049)
3%
(5%)
S 272nd Street / Military Road (City of
Kent/King County) – Change north-
south split signal phasing to
conventional signal phasing.
Change should be included in
King County and City of Kent
plans for intersection
improvements.
Change should be included in
King County and City of Kent
plans for intersection
improvements.
Change should be included in
King County and City of Kent
plans for intersection
improvements.
4,028 4,079
(4,111)
1%
(2%)
SE 304th Street / 112th Avenue SE City
of Auburn – Signalize and widen
intersection to provide left-turn lanes.
Contribute proportional share. Contribute proportionate share
when City adds project on its TIP
and acquires right of way
Contribute proportionate share
when City adds project on its TIP
and acquires right of way
1559 1,678
(1,721)
7%
(9%)
45th Street NE at Auburn Way North –
Signalize when warranted
Construct when warranted Construct when warranted Construct when warranted 2,475 2,837
(2,924)
13%
(15%)
45th Street NE at I Street NE –
Signalize when warranted
Construct when warranted Construct when warranted Construct when warranted 626 1,188
(1,423)
47%
(56%)
1. No-Build Full Network Volumes represent the future without development conditions with the future road network complete (i.e. I Street NE extended between S 277th Street and 45th Street NE)
2. Retail (Office) represents the 2020 Full Build Retail Only and Office/Retail Volumes with a Signal at 45th Street NE/ Auburn Way NE conditions
1.
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
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Significant Unavoidable Adverse Impacts
The revised road layout and the addition of Auburn Gateway II area would not result in
significant unavoidable adverse impacts. Traffic impacts are expected to be equivalent to
or less than what was described in the 2004 Draft EIS in most cases, and in no case are
the increased impacts considered significant.
As described in the 2004 Draft EIS, all of the development alternatives would result in
additional traffic at several intersections that would operate at LOS F in the future. The
DEIS and this addendum did not identify mitigation for three intersections at which the
project would cause an increase in delay: South 277th Street/West Valley Highway,
Central Avenue/Willis Street, and 116th Avenue SE/Kent-Kangley Road. These three
intersections would operate at LOS F regardless of whether the proposed project is
developed.
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
November 2011 55
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Environmental Elements not Analyzed
The following briefly discusses the reasons that additional analysis was not performed for
other elements of the environment discussed in the EIS.
Geology/Soils
No change is expected for impacts related to geology and soils due to the development of
Auburn Gateway II. There is no topographic break or obvious change in vegetation that
would suggest a change in soils between Auburn Gateway I and Auburn Gateway II
project areas.
Air Quality
No change is expected for impacts related to air quality due to the development of
Auburn Gateway II. The analysis in the 2004 Draft EIS to determine maximum peak hour
carbon monoxide concentrations by examining intersections that would be most affected
by the project is still relevant. The development of Auburn Gateway II would not result in
an increase in project-related trips because the same amount of retail and office square
footage and residential units is proposed for the project as that evaluated in the 2004 EIS.
There would be some changes in traffic circulation related to D Street NE and 49th Street
NE. The change in traffic circulation is expected to reduce the volume of traffic at South
277th Street and Auburn Way North during the PM peak hour under Alternative 2, an
intersection studied in the 2004 EIS for carbon monoxide concentrations. This change is a
result of background traffic diverting to internal streets such as 49th Street NE and I
Street NE. Under Alternative 2, traffic volumes are expected to be distributed over more
intersections, reducing delay at Auburn Way North and South 277th Street and slightly
increasing delay at minor intersections like 49th Street NE and Auburn Way North
(Transportation Solutions, Inc., 2010). Less delay at the Auburn Way North and South
277th Street would likely result in less carbon monoxide concentrations during PM peak
hour than shown in the 2004 EIS under Alternative 2.
Noise
No change is expected for impacts related to noise due to the development of Auburn
Gateway II. Temporary construction noise associated with Auburn Gateway II would be
more noticeable to noise-sensitive receivers along D Street NE. Operational noise from
project-related traffic is not expected to noticeably change from what was described in
the 2004 EIS. This is because development of Auburn Gateway II would not result in an
increase in project-related trips since the same amount of retail and office square footage
and residential units is proposed for the project as evaluated in the 2004 EIS. There
would be some changes in traffic circulation related to D Street NE and 49th Street NE.
The change in traffic circulation is not expected to increase impacts to noise sensitive
receivers. Of the four noise study focus areas studied in the 2004 EIS, only residences
along D Street NE would find project-related traffic to have noticeably increased noise
levels. The proposed change in traffic circulation would not increase traffic volume along
D Street any further than what was evaluated in the 2004 EIS.
NE Auburn/Robertson Properties Special Area Plan EIS Addendum
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Hazardous Materials
No change is expected for impacts related to hazardous materials due to the development
of Auburn Gateway II. A Phase I Site Assessment was conducted by Landau Associates,
Inc. in 2007 to assess and document environmental conditions that may pose a potential
liability to a prospective purchaser in the Auburn Gateway II project site area. The
assessment revealed no evidence of recognized environmental conditions, as defined by
American Society for Testing and Materials, in connection with the subject property.
Recognized environmental conditions are defined as the presence or likely presence of
any hazardous substances or petroleum products under conditions that indicate an
existing release, a past release, or a material threat of a release of any hazardous
substances or petroleum products into structures on the subject property or into the
ground, groundwater, or surface water of the subject property. (Landau Associates, Inc.,
2007).
Cultural and Historic Resources
No change is expected for impacts related to cultural and historic resources due to the
development of Auburn Gateway II. The 2004 Draft EIS evaluated the planning area
which includes the Auburn Gateway II site and the Auburn Gateway I site for the
potential of discovering cultural and historic resources. The 2004 Draft EIS indicated that
within the planning area, there is a high probability of hunter-fisher-gatherer,
ethnographic period and historic Indian, and historic period archaeological resources. The
probability estimates for the Auburn Gateway project area and the planning area were
based on the availability of the Duwamish River – Green River floodplain for hunter-
fisher-gatherer use, soils data that indicate old channels and low terrace deposits,
prehistoric and historic period land use in similar environmental settings, and
documented ethnographic and historic period land use in these two areas.
Land Use
No change is expected for impacts related to land uses due to the development of Auburn
Gateway II if the same comprehensive plan and C4, Mixed Use Commercial zoning
designations apply. Auburn Gateway II would be developed with retail, office and/or
residential units, parking lots, and stormwater facilities similar to Auburn Gateway I. The
same amount of retail, office, and/or residential development that was evaluated in the
2004 Draft EIS would be constructed but the development would be spread out into a
larger geographic area. The private residences and commercial facility located south of
the Auburn Gateway II project site would be affected by the change from a low-intensity
setting with relatively quiet surroundings to commercial, office and/or residential
activities, but the nature of the impact would be similar to those evaluated in the 2004
EIS.
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November 2011 57
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Recreation
No change is expected for impacts related to recreation due to the development of
Auburn Gateway II. The development of Auburn Gateway II would not affect the
development of a Class I Trail along the south side of South 277th Street or the internal
trail connections proposed as part of Auburn Gateway I and identified in the proposed
Auburn Gateway Design Guidelines. The recreational demand as a result of retail, office,
and/or residential development would be the same as what was evaluated in the 2004
Draft EIS since the project proposes the same amount of development evaluated in the
2004 EIS.
Aesthetics
No change is expected for impacts related to aesthetics due to the development of Auburn
Gateway II if the applicant’s same architectural and site design standards apply. Auburn
Gateway II would be developed in the same manner as Auburn Gateway I with retail,
office, residential or mixed-use structures, surface parking lots, and stormwater facilities.
The 2004 Final EIS estimated that 650,000 cubic yards of fill may be necessary to
implement the Preferred Alternative. Based on the current site plan and addition of the
Auburn Gateway II property, RPG is currently proposing to fill approximately 600,000 to
750,000 cubic yards for the Auburn Gateway I and II sites. Additional fill may raise the
project even higher than the grades described in the 2004 EIS making the bulk and scale
of the development more apparent. However, the Auburn Gateway Design Guidelines
proposed in the 2004 Draft EIS together with the landscaping and other measures
required by the Auburn City Code, include measures to mitigate the aesthetic impacts of
the project that would be effective in addressing this additional impact.
Utilities and Public Services
No change is expected for impacts related to utilities, except storm drainage systems, and
public services due to the development of Auburn Gateway II. The same amount of retail,
office and/or residential development that was evaluated in the 2004 Draft EIS would be
constructed but the development would be spread out into a larger geographic area.
Therefore, the estimate for domestic water consumption and wastewater production
associated with development in the 2004 Draft EIS is still accurate. . In order to ensure
orderly and efficient extensions of public utilities consistent with the proposed phasing
and city regulations, a master plan is to be provided prior to construction authorizations.
The fiscal impact analysis associated with fire, emergency medical, and police service is
also still applicable.
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58 November 2011
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