HomeMy WebLinkAboutERC_Report_Sounders_FINALDEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
ERC_Sounders_v2
ENVIRONMENTAL REVIEW COMMITTEE REPORT
ERC Meeting Date: November 7, 2022
Project File Number: PR22-000301
Project Name: Sounders FC Center at Longacres
Land Use File Number: LUA22-000357, SA-H, CU-H, ECF, MOD
Project Manager: Jill Ding, Senior Planner
Owner: Unico Longacres South Building LLC, Unico Longacres South Campus Land LLC,
Unico Longacres Central Drainage LLC, 1215 4th Ave, Suite 600, Seattle, WA 98161
Applicant: Unico Properties, 1215 4th Ave, Suite 600, Seattle, WA 98161 and
Seattle Soccer, LLC, d/b/a Seattle Sounders FC, 406 Occidental Avenue S, Seattle,
WA 98104
Contact: Julia Reeve, Unico Properties, 1215 4th Ave, Suite 600, Seattle, WA 98161 and
Tom Chiado, Chiado LLC, PO Box 10104, Bainbridge Island, WA 98110
Project Location: 1901 Oaksdale Ave SW, Renton, WA 98057 (Parcel Nos. 0886700220, 0886700110,
0886700120, 0886700130, 0886700210, 0886700370, and 0886700140)
Project Summary: The applicant is requesting a Hearing Examiner Conditional Use Permit, Hearing
Examiner Site Plan Review, Environmental (SEPA) Review, and a Street Modification
for the use of a portion of an existing office building for Sounders FC office space and
indoor training facilities and associated activities, outdoor recreation facilities
including 5 full-size soccer fields a Goal Keepers Field and accessory structures, and
reconfiguration of and existing surface parking lot. The overall project site totals
approximately 30 acres in area and is zoned Commercial Office (CO). Access to the
Site would be maintained via existing curb cuts off Oakesdal e Ave SW. The project
site is currently developed with an existing 5-story office building totaling
approximately 311,982 sq. ft., and the Sounders propose to lease approximately
50,000 sq. ft. of floors 1 and 2. A new accessory viewing deck proposed to ov erlook
Field 1 from floor 2 would total approximately 1,650 sq. ft. in area. Some existing
surface parking would be removed for the placement of Fields 1 and 2 and additional
parking would be removed to create a secure 1st team parking area in the existing
southern parking lot. The total remaining parking area would include approximately
766 surface parking stalls. A maintenance building (approximately 4,000 sq. ft.) and
future field restroom (approximately 800 sq. ft.) are proposed to be co-located
between fields 2 and 4. A Modification to the City's Street Standards was requested
to maintain the existing frontage improvements around the project site. The project
site is mapped with high seismic hazard areas, wetlands, and flood hazard areas. A
Category II wetland was identified to the northwest of the project site, a Category II
wetland has a standard buffer of 100 feet for low impact land uses and 150 feet for
all other land uses. The proposal includes a reduction in the standard buffer width in
the vicinity of the soccer fields and the paper fill of the wetland. Wetland buffer
enhancement plantings and the purchase of wetland mitigation bank credits are
proposed to mitigate the indirect wetland impacts and impacts to the buffer.
Exist. Bldg. Area SF: 311,982 gross sq.
ft.
Proposed New Bldg. Area (footprint):
Proposed New Bldg. Area (gross):
4,800 sq. ft.
4,800 sq. ft.
Site Area: approx. 30 acres Total Building Area GSF: 316,782 sq. ft.
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 2 of 12
ERC_Sounders_FINAL
STAFF
RECOMMENDATION:
Staff Recommends that the Environmental Review Committee issue a
Determination of Non-Significance - Mitigated (DNS-M).
Project Location
ENVIRONMENTAL REVIEW
In compliance with RCW 43.21C.240, the following environmental (SEPA) review addresses only those project impacts
that are not adequately addressed under existing development standards and environmental regulations.
A.Environmental Threshold Recommendation
Based on analysis of probable impacts from the proposal, staff recommends that the Responsible Officials:
Issue a DNS-M with a 14-day appeal period
B.Mitigation Measures
1.Construction on the project site shall comply with the recommendations of the submitted Geotechnical
Report, prepared by GeoEngineers, dated June 23, 2022.
2.The applicant’s geotechnical engineer shall review the project’s construction plans for the new fields and
the building permit plans for the proposed maintenance building and elevated patio addition to verify
compliance with the submitted geotechnical report. The geotechnical engineer shall submit a sealed letter
stating that he/she has reviewed the construction and building permit plans and in their opinion the plans
and specifications meet the intent of the report.
3.The fill material used on the synthetic fields shall be comprised of a material that would be non -toxic to
fish and other wildlife.
4.The applicant shall demonstrate that the proposed underground storage chambers, to be utilized for
compensatory storage, would not have an adverse impact on salmonids and would ensure that salmonids
would not get trapped within the proposed underground storage chambers.
5.The applicant shall follow the Department of Ecology guidance for Tacoma Smelter Plume soil
contamination testing and remediation as instructed in the agency’s letter (Exhibit 15).
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 3 of 12
ERC_Sounders_FINAL
6.The applicant shall submit an Inadvertent Discoveries Plan prepared by a qualified professional with the
civil construction permit for review and approval by the Current Planning Project Manager prior to permit
issuance.
C.Exhibits
Exhibit 1:Environmental Review Committee (ERC) Report
Exhibit 2:Site Plan
Exhibit 3:Civil Plan Set
Exhibit 4:Colored Rendering
Exhibit 5:SEPA Checklist
Exhibit 6:Geotechnical Report, prepared by GeoEngineers, dated June 23, 2022
Exhibit 7:Critical Areas - Existing Conditions Letter Report prepared by Talasaea, dated April 29,
2022
Exhibit 8:Critical Areas Report and Conceptual Mitigation Plan prepared by Talasaea, dated
October 7, 2022
Exhibit 9:Otak’s Peer Review Memorandum, dated June 9, 2022
Exhibit 10:Otak’s Peer Review Memorandum, dated November 2, 2022
Exhibit 11:Civil Engineering Narrative, prepared by Coughlin Porter Lundeen, dated August 8, 2022
Exhibit 12:Technical Information Report (TIR) prepared by Coughlin Porter Lundeen, dated August
2022
Exhibit 13:Arborist Report, prepared by American Forest Management, Inc., dated August 1, 2022
Exhibit 14:Lighting Plan
Exhibit 15:Public Comments
Exhibit 16:Trip Generation Memo, prepared by Transportation Engineering Northwest, dated June
27, 2022
Exhibit 17:Transportation Concurrency
Exhibit 18:Advisory Notes
Exhibit 19:Street Frontage Improvements Modification Justification
D.Environmental Impacts
The Proposal was circulated and reviewed by various City Departments and Divisions to determine whether the
applicant has adequately identified and addressed environmental impacts anticipated to occur in conjunction with
the proposed development. Staff reviewers have identified that the proposal is likely to hav e the following probable
impacts:
1.Earth
Impacts: A Geotechnical Report, prepared by GeoEngineers, dated June 23, 2022 (Exhibit 6) was
submitted with the project application materials. According to the submitted SEPA Checklist (Exhibit 5),
the proposal would include the excavation of approximately 4,185 cubic yards of material and the infill of
approximately 26,588 cubic yards of material for the construction of the fields. In addition, the applicant
submitted a Technical Information Report (TIR) prepared by Coughlin Porter Lundeen, dated August 2022
(Exhibit 12). According to the submitted TIR, approximately 718,000 cubic feet of fill is proposed within
the currently delineated 100 year floodplain.
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 4 of 12
ERC_Sounders_FINAL
According to the submitted report, the existing site topography slopes gradually from west to east from
approximately Elevation 17 feet to 10 feet. Information regarding subsurface conditions was based on a
review of existing geotechnical information on and around the project site. No new subsurface
explorations were conducted on the project site. The soils encountered in the vicinity of the project site
consist of shallow fill overlying alluvial deposits, beach deposits, and glacially consolidated soils. The fill
generally consists of very soft to stiff silt and to medium silty sand with varying amounts of gravel. Fill in
the vicinity of the site ranged to approximately 6 feet in depth. The alluvial deposits were encountered at
the existing ground surface or beneath the fill. The alluvial soil generally consists of loose to medium dense
sands and gravels with varying amounts of silt and very soft to medium stiff silt. The sand and silty sand
deposits were generally interbedded with lenses of soft to medium stiff organic silt. The alluvial deposits
in the vicinity of the site range up to approximately 45 feet in depth. Beach deposits are present below
the alluvial deposits and consist of medium dense to very dense sand and gravel with variable silt content.
The glacially-consolidated soils were encountered below the beach deposits and extended to the depths
explored in the borings and cone penetration tests (CPT). The glacially -consolidated soils consist of
medium dense to very dense sands with varying amounts of silt and gravel.
It is anticipated that the ground water levels in the vicinity of the site would fluctuate as a function of
season, precipitation and water levels in the Green River. Based on the applicant’s review of the available
subsurface information, the regional groundwater table in the project vicinity varies seasonally at the site
and is near the ground surface elevation during extended periods of wet weather.
A high seismic hazard is mapped on the project site. According to the submitted geotechnical report, the
loose to medium dense sand which underlies the project site has a moderate to high risk of liquefying.
The existing fill and alluvial deposits encountered in the explorations contain a high percentage of fines
and are highly moisture sensitive. It is anticipated that the operation of equipment on these soils would
be difficult during the wet season (typically October through May) and in wet weather conditions. In
addition, the report recommends that the design of the fields consider estimated site settlement due to
the presence of the underlying fill and alluvial deposits. In addition to being susceptible to liquefaction,
the alluvial soils are compressible and are expected to settle under new/increased loading conditions.
Static settlements will depend on the thickness of new fill placed.
The report included recommendations for site preparation and earthwork, excavations and permanent
slopes, utility trenches, pavement recommendations, and recommended additional geotechnical services
for the construction of the proposed fields, however the report did not include a discussion on the
proposed maintenance building and elevated exterior patio addition. Due to the concerns expressed in
the submitted geotechnical report regarding soil stability on the project site, staff recommen ds as SEPA
mitigation that construction on the project site comply with the recommendations of the submitted
Geotechnical Report, prepared by GeoEngineers, dated June 23, 2022. The applicant’s geotechnical
engineer should review the project’s construction plans for the new fields and the building permit plans
for the proposed maintenance building and elevated patio addition to verify compliance with the
submitted geotechnical report. The geotechnical engineer shall submit a sealed letter stating that he/she
has reviewed the construction and building permit plans and in their opinion the plans and specifications
meet the intent of the report.
Mitigation Measures:
1.Construction on the project site shall comply with the recommendations of the submitted
Geotechnical Report, prepared by GeoEngineers, dated June 23, 2022.
2.The applicant’s geotechnical engineer shall review the project’s construction plans for the
new fields and the building permit plans for the proposed maintenance building and
elevated patio addition to verify compliance with the submitted geotechnical report. The
geotechnical engineer shall submit a sealed letter stating that he/she has reviewed the
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 5 of 12
ERC_Sounders_FINAL
construction and building permit plans and in their opinion the plans and specifications
meet the intent of the report.
Nexus: SEPA Environmental Regulations
2.Water
a.Wetland
Impacts: A Critical Areas - Existing Conditions Letter Report prepared by Talasaea, dated April 29, 2022
(Exhibit 7) and a Critical Areas Report and Conceptual Mitigation Plan prepared by Talasaea, dated
October 7, 2022 (Exhibit 8) were submitted with the project application materials. The submitted
critical areas reports identified Wetlands A and F, Pond B, Feature D, and Feature G on the project
site. Wetland A is located along the eastern boundary of the project site and would be classified as a
Category II wetland with a moderate habitat score. Wetland F is located to the north of the project
site and would also be regulated as a Category II wetland with a moderate habitat score. Category II
wetlands with a moderate habitat score require a 100-foot buffer for low impacts land uses and a
150-foot buffer for all other land uses. It has been determined that the proposed soccer fields would
qualify as low impact land uses and would be subject to a 100-foot buffer.
Pond B is a stormwater detention and treatment pond located directly south of Wetland A, along the
east side of the project site, and would not be classified as a regulated wetland . Pond B hydrology is
provided by direct surface flow during rain events and from the stormwater detention pond located
to the south.
Feature D is an upland area located upslope and east of Pond B. Both test plots conducted within
Feature D failed to satisfy the requirements of a hydrology indicator, and one (1) of the two (2) test
plots failed to satisfy the requirements of either a hydrology or hydric soil indicator. Feature D
hydrology, when present, appears to be historically provided by an installed irrigation system which
draws water directly from Pond B. Aside from the installed irrigation system, hydrology can only
otherwise be provided by direct precipitation due to local topography. Feature D is an area that is
indicative of intentional plantings designed to make the area visually appear as a wetland. Feature D
would not be classified as a regulated wetland.
Feature G is identified as being a site of stormwater treatment by the City of Renton and indicates
numerous private surface water mains entering and exiting the area. Feature G would not be classified
as a regulated wetland.
The submitted Critical Areas - Existing Conditions Letter Report (Exhibit 7) was reviewed by the City’s
environmental consultant, Otak. Otak’s findings were summarized in a Peer Review Memorandum,
dated June 9, 2022 (Exhibit 9). Otak concurred with the assessment and delineation of Wetlands A
and F and also concurred that Pond B, Feature D, and Feature G would not be classified as regulated
wetlands.
The proposed site plan (Exhibit 2) shows the proposed keeper/training area and Field 1 within the
100-foot buffer of Wetland A. The proposal would have no direct impact to Wetland A, although it
would reduce the 100-foot buffer to approximately 32 feet, resulting in the alteration of
approximately 15,467 sq. ft. of Wetland A’s buffer. The maximum buffer reduction permitted by the
City’s adopted Critical Areas Regulations is 25% or a 25 -foot reduction of a 100-foot buffer (RMC 4-3-
050I). The proposal would result in an approximately 68% reduction in the standard buffer, which is
greater than the buffer reduction permitted by the City’s Critical Areas Regulations. Following the
guidelines outlined by the Washington State Department of Ecology Publication 21-06-003, the
alteration would be achieved through the use of Wetlands as Buffers (often referred to as “paper fill”).
Conversion of wetland into buffer does not actually fill any wetland; wetland converted into buffer
still functions as a wetland in the landscape. To mitigate for the “paper fill” impacts to Wetland A, the
proposal would be required to comply with the City’s Critical Areas Regulations for Alterations to
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 6 of 12
ERC_Sounders_FINAL
Wetlands (RMC 4-3-050J.4) and provide the appropriate mitigation ratio for indirect wetland impacts.
The applicant’s Conceptual Mitigation Plan (Exhibit 8) would include the purchase of credits from the
Springbrook Creek Wetland Mitigation Bank. The applicant proposes a mitigation ratio of 50% (i.e.,
0.5:1.0) for its indirect impact to Wetland A that causes no or only partial loss of e cological functions
to the wetland. In addition, the applicant is proposing to enhance the upland buffer of Wetland A
existing between the proposed field locations and the wetland edge, an area of approximately 15,151
sq. ft. in size. Most of this buffer area is in good ecological condition; however, some areas are
dominated by invasive plant species and would benefit from enhancement. The proposed area of
buffer enhancement would total approximately 4,616 sq. ft. within the 15,151 sq. ft. buffer area.
Secondary review of the Critical Areas Report and Conceptual Mitigation Plan (Exhibit 8) was
conducted in a Peer Review Memorandum, prepared by Otak, dated November 2, 2022 (Exhibit 10).
The Peer Review Memorandum notes that the submitted Mitigation Plan proposes no direct impacts
to Wetland A, and 15,467 sq. ft. of indirect impacts from the proposed encroachment into the
Wetland A buffer. Mitigation of these impacts is proposed through a combination of mitigation credit
purchase through the Springbrook Creek Mitigation Bank at a 0.5:1 ratio, and 4,616 square feet of
buffer enhancement in areas of the Wetland A upland buffer dominated by invasive species. The
proposed buffer enhancements would be subject to maintenance and monitoring for a period of five
(5)years per RMC 4-3-050L(2) and RMC 4-3-050L(3). In general, the Peer Review Memorandum
(Exhibit 10) takes no issue with the proposed mitigated strategy, however there were some
outstanding comments that needed to be addressed prior to formal approval. The resolution of these
comments would be discussed further in the Staff Recommendation to the Hearing Examiner for the
Site Plan Review application.
It is anticipated that the City’s adopted Critical Areas Regulations would adequately mitigate for any
impacts to Wetlands A and F, therefore no further mitigation is recommended.
Mitigation Measures: None Recommended
Nexus: N/A
b.Floodplain
Impacts: The project site is located within the 100-year floodplain of Springbrook Creek. The applicant
submitted a Critical Areas Report and Conceptual Mitigation Plan prepared by Talasaea, dated
October 7, 2022 (Exhibit 8), which included a Biological and Habitat Assessment. The Biological and
Habitat Assessment identifies Endangered Species Act (ESA) listed or candidate species potentially
within the Project-affected areas or maybe affected by the proposed action. Species listed under the
Endangered Species Act fall under the jurisdiction of one (1) of two (2) federal agencies: the U.S. Fish
and Wildlife Service (USFWS) for terrestrial and freshwater species, and the National Oceanogr aphic
and Atmospheric Administration (NOAA) National Marine Fisheries Service (NMFS) for marine and
anadromous species. As indicated in the USFWS Information for Planning and Conservation Report
(IPaC): The Marbled Murrelet (Brachyramphus marmoratus) is designated as Threatened, the
Streaked Horned Lark (Eremophila alpestris strigata) is designated as Threatened, the Western Yellow-
billed Cuckoo (Coccyzus americanus) is designated as Threatened, Bull Trout (Salvelinus confluentus)
is designated as Threatened, and the Monarch Butterfly (Danaus plexippus) is designated as a
Candidate Species.
The NOAA Fisheries website and Washington Department of Fish and Wildlife’s (WDFW) Priority
Habitats and Species (PHS) website were used to review listed species within the vicinity of the project
site. Two (2) ESA-listed Pacific salmon species are potentially within the Project-affected area, or may
be affected by the proposed action: Puget Sound Chinook (Oncorhynchus tshawytscha), designated
as Threatened, and Puget Sound Steelhead (Oncorhynchus mykiss) designated as Threatened. There
is final designated critical habitat for both salmon species within the Project-affected area,
Springbrook Creek. Springbrook Creek is approximately 1,150 feet from the project site.
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 7 of 12
ERC_Sounders_FINAL
The Critical Areas Report (Exhibit 8) concludes that the proposed construction and operation of the
Sounders facilities would not directly affect any of the above ESA-listed species. The entirety of the
site development work takes place in an existing urban area with no significant habitat features for
any of the species listed above. The project site is located nearly 1,900 feet from the Green River and
is outside of its drainage basin. While the project site is located within the Springbrook Creek/Black
River subbasin area, it is approximately 1,150 feet from Springbrook Creek and has no direct
connection or impact to Springbrook Creek. However, secondary review of the applicant’s Critical
Areas Report was conducted by the City’s Environmental Consultant (Otak). Concerns were expressed
regarding the fill that would be placed within the synthetic fields. There are some fill materials that
have been determined to be toxic to fish. To ensure that the fill placed within the synthetic turf fields
does not adversely impact fish species, staff recommends, as a SEPA mitigation measure that the fill
material used on the synthetic fields be comprised of a material that would be non -toxic to fish and
other wildlife.
A Civil Engineering Narrative, prepared by Coughlin Porter Lundeen, dated August 8, 2022 (Exhibit 11)
was submitted with the project application materials and included a discussion on the grading
proposed within the floodplain. The proposed project would include approximately 575,000 sq.ft. of
sports fields, which will result in the placement of approximately 718,000 cubic feet of fill within the
currently delineated 100-year floodplain. As required by the City’s Critical Areas Regulations,
floodplain fill mitigation would be required in the form of compensatory storage below the record
Base Flood Elevation (BFE). This BFE is listed as at 20-foot elevation at the southern area of the
Sounders fields, and roughly 19.6 to 19.7 at the northern edge. The compensatory mitigation proposal
would be to calculate the proposed compensatory volume using a BFE of 20.0 across the entire field
project limits, which would exceed the minimum volume required.
The required compensatory volume is proposed to be provided using a series of underground storage
chambers (StormTech or Eq) to hold the required flood plain fill mitigation volume of floodwater.
These chambers would connect to open, screened inlet/outlet pipes that extend below the Pond B
water surface. The chambers would begin to store replacement flood volume when the pond
elevation reaches its maximum detention water surface elevation of 14.7 feet. A discussion of
whether or not the proposed compensatory storage would adversely impact salmonids, ensuring they
do not get trapped within this system was not included. Therefore, staff recommends as a SEPA
Mitigation Measure that the applicant demonstrate that the proposed compensatory storage,
underground storage chambers, not have an adverse impact on salmonids and ensures that salmonids
would not get trapped within the proposed underground storage chambers.
The proposal indicates that approximately 718,000 CF of fill within the floodplain would be added and
that 850,000 CF of compensatory storage is proposed to be provided. As the proposal would provide
more volume than 718,000 cubic feet that is required to compensate for the fill for the construction
of the fields, the applicant is proposing to set aside or “bank” the additional compensation volume for
future fill placed elsewhere on the Longacres campus under potential future redevelopment projects.
Mitigation Measures:
1.The fill material used on the synthetic fields shall be comprised of a material that would be non -
toxic to fish and other wildlife.
2.The applicant shall demonstrate that the proposed underground storage chambers, to be utilized
for compensatory storage, would not have an adverse impact on salmonids and would ensure
that salmonids would not get trapped within the proposed underground storage chambers.
Nexus: SEPA Environmental Regulations
c.Storm Water
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 8 of 12
ERC_Sounders_FINAL
Impacts: A Technical Information Report (TIR) prepared by Coughlin Porter Lundeen, dated August
2022 (Exhibit 12) was submitted with the project application materials. The proposed project would
be subject to the requirements of the 2022 City of Renton Surface Water Design Manual. The existing
site consists of open grassy areas, a large existing office building with associated plaza and paved
pedestrian walkways. The site was previously home to the Longacres Racetrack outbuilding stable and
support services area, which was demolished during the development of the existing Longacres Office
Park, of which this project site is a portion of. Minimal conveyance systems exist within the project
site area and runoff now leaves the site via surface flow which makes its way ultimately to Pond B.
The existing site topography slopes gradually from west to east.
The project proposal would utilize the existing surface water facilities that were previously
constructed onsite (i.e. Pond B) and would also include the installation of a new onsite drainage
system. The proposed drainage system would include a new network of underground pipes and catch
basins, to collect the drainage from the surface and under-drain system of the proposed sports fields,
as well as the surface water runoff from the walkways and other areas adjacent to the fields within
the project site. This system would direct runoff to a flow splitter that would direct larger flows that
do not require water quality treatment, directly to Pond B. Smaller flows w ould be directed to the
proposed water quality treatment system. Flows from this facility would also, eventually discharge
into the existing Pond B.
In order to provide the required enhanced basic water quality treatment for the soccer fields, the
project proposes to install a Bioscape open system using Filterra media, along the western edge of
Pond B, downstream of the fields.
Staff received comments from the Washington State Department of Ecology (DOE) (Exhibit 15)
requesting additional information regarding the proposed dewatering procedures to the
implemented onsite. The dewatering procedures would be reviewed at the time of Construction
Permit review and would be regulated through the City’s adopted 2022 City of Renton Surface Water
Design Manual; therefore, no further mitigation is recommended at this time.
It is anticipated that the City’s adopted 2022 City of Renton Surface Water Design Manual would
adequately mitigate impacts from surface water runoff, therefore no further mitigation is
recommended.
Mitigation Measures: None recommended
Nexus: N/A
3.Vegetation
Impacts: According to the submitted Critical Areas Report and Conceptual Mitigation Plan (Exhibit 8)
submitted with the application materials, the areas directly adjacent to the existing office building and
surface parking lot are vegetated by maintained lawn and other landscape plantings. Other plant
communities across the site are composed of native tree species, including black cottonwood (Populus
balsamifera ssp. trichocarpa) and red alder (Alnus rubra), with occasional Douglas-fir (Pseudotsuga
menziesii), western redcedar (Thuja plicata), bigleaf maple (Acer macrophyllum), and others. The Site also
features several shrubs and saplings including Sitka willow (Salix sitchensis), salmonberry (Rubus
spectabilis), vine maple (Acer circinatum), and others. Throughout the Site, there is a prevalence of non-
native and invasive Himalayan blackberry (Rubus armeniacus), reed canarygrass (Phalaris arundinacea),
and English ivy (Hedera helix).
An Arborist Report, prepared by American Forest Management, Inc., dated August 1, 2022 (Exhibit 13)
was also submitted with the land use application materials. The City’s adopted Tree Retention Regulations
require a retention percentage of thirty percent (30%) of onsite significant trees (after the deduction of
trees within areas of public right-of-way dedication and critical areas and buffers). According to the
submitted arborist report, there are a total of 605 significant trees on the project site, of those 24 would
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 9 of 12
ERC_Sounders_FINAL
qualify as high-risk trees, resulting in 581 viable significant trees on the project site, of which two (2)
cottonwood trees would be considered landmark trees. The proposal would include the removal of 377
trees (including one (1) landmark tree) for the development of the proposed soccer fields, resulting in the
retention of 204 trees and one landmark trees. The proposal to retain 204 significant trees would result
in a retention percentage of thirty five percent (35%), which exceeds the City’s minimum tree retention
requirements.
The City’s Tree Retention Regulations also require that a minimum tree density of 30 credits per net acre.
The submitted arborist report (Exhibit 13) included a tree density calculation and concluded that the
retained trees would result in the provision of 30.2 tree credits on the project site, which would satisfy
the minimum tree density requirements.
It is anticipated that any adverse impacts to onsite vegetation would be mitigated through the City’s
adopted Tree Retention Regulations, therefore no further mitigation is recommended.
Mitigation Measures: None recommended
Nexus: N/A
4.Wildlife
Impacts: As previously discussed above in the Floodplain section of this report, a Critical Areas Report and
Conceptual Mitigation Plan prepared by Talasaea, dated October 7, 2022 (Exhibit 8), which included a
Biological and Habitat Assessment was submitted. Talasaea Consultants used the IPaC web application
provided by USFWS, which compiles a species list of ESA -listed or candidate terrestrial and freshwater
species that are potentially within a Project-affected area, or may be affected by a proposed action.
Application of the IPaC to the Project Site identified Five (5) ESA-listed or candidate species are potentially
within the Project-affected area, or may be affected by the proposed action: Marbled Murrelet, Streaked
Horned Lark, Western Yellow-billed Cuckoo, Bull Trout and Monarch Butterfly. However, based on Site-
specific investigation and analysis of habitat requirements, all terrestrial species listed are not within the
Project-affected area, nor have designated critical habitat within the Project-affected area. The Monarch
Butterfly is a candidate species not requiring consultation under ESA. Two (2) ESA-listed Pacific salmon
species have designated critical habitat outside the Project Site, at Springbrook Creek: Puget So und
Chinook and Puget Sound Steelhead. Springbrook Creek is approximately 1,150 feet from the project site.
The submitted Biological and Habitat Assessment concluded: “that the construction and operation of the
Sounders facilities will not directly affect any ESA-listed or candidate species and will not result in a “take”
as defined by the Endangered Species Act.” It is anticipated that any adverse impacts to wildlife would be
mitigated through the implementation of the City’s Critical Areas Regulations, therefore no further
mitigation is recommended.
Mitigation Measures: None recommended
Nexus: N/A
5.Environmental Health
a.Environmental Health Hazards
Impacts: Staff received comments from DOE (Exhibit 15), that the site is located within an area that
may have been contaminated with heavy metals due to air emissions originating from the former
Asarco smelter plant in north Tacoma. As such, contaminated soils may be located on the project site.
DOE recommends that mitigation measures be applied to the project proposal regarding hazardous
waste operation workers training, health and safety plan, and site control requirements and the
management of contaminated soil or groundwater encountered during construction, including
sampling, containment, and disposal at a permitted facility.
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 10 of 12
ERC_Sounders_FINAL
To address the comments received from the Department of Ecology, staff recommends, as a SEPA
mitigation measure, that the applicant follow the Department of Ecology guidance for Tacoma
Smelter Plume soil contamination testing and remediation as instructed in the agency’s letter (Exhibit
15).
Mitigation Measures:
1.The applicant shall follow the Department of Ecology guidance for Tacoma Smelter Plume soil
contamination testing and remediation as instructed in the agency’s letter (Exhibit 15).
Nexus: Renton Comprehensive Plan Policy U-32: Work to protect surface and groundwater resources
from pollutants entering the storm drainage system and SEPA Environmental Regulations
6.Light and Glare
Impacts: A lighting plan (Exhibit 14) was submitted with the project application materials. Within the field
complex field lighting is proposed. The proposed light poles would include directional LED lights designed
specifically to light fields after dark but directed solely at the fields and preventing light pollution outside
of the field complex. Use of field lights would generally be restricted to when it is needed for visibility
during evening training sessions, or possibly off-hours maintenance activities. Evening training most
frequently occurs on turf fields (which are proposed to be located furthest from Wetland A) from 4:00 -
9:00 pm. The duration of field lighting would depend upon the time of year. For example, a winter training
session may require five (5) hours of lighting, where a summer session might not require any. Occasionally,
lighting may be used during special events on the proposed fields. It is anticipated that impacts resulting
from the proposed field lighting would be adequately mitigated through the City’s adopted lighting
regulations, therefore no further mitigation is recommended.
Mitigation Measures: None recommended
Nexus: N/A
7.Historic and Cultural Preservation
Impacts: No archeological studies were submitted with the project application materials. The project site
has been redeveloped on at least three (3) separate occasions: (1) farming, (2) Longacres horse racetrack,
(3) Boeing Headquarters, which included extensive stormwater and drainage facilities in the fields
surrounding the existing office building (Building 25-20). As the existing site has been subject to
development and redevelopment on multiple occasions, the applicant contends that it is highly unlikely
that this proposal would encounter any potential archeological evidence.
Staff did receive comments from the Duwamish Tribe (Exhibit 15) requesting that an archeological survey
be conducted onsite prior to proposed construction activities due to the potential for archeological
resources being discovered on the project site. To ensure that any archeological deposits are managed
appropriately, staff recommends as a SEPA mitigation measure that the applicant submit an Inadvertent
Discoveries Plan prepared by a qualified professional with the civil construction permit for review and
approval by the Current Planning Project Manager prior to permit issuance.
Mitigation Measures:
1.The applicant shall submit an Inadvertent Discoveries Plan prepared by a qualified professional with
the civil construction permit for review and approval by the Current Planning Project Manager prior
to permit issuance.
Nexus: SEPA Environmental Regulations
8.Transportation
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 11 of 12
ERC_Sounders_FINAL
Impacts: The applicant submitted a modification request (Exhibit 19) requesting that the existing street
frontage improvements be retained on and around the project site and that the construction of new
frontage improvements be deferred to a later date, when a formal Master Plan application is submitted
for the redevelopment of the Longacres site as a whole. Further discussion of the requested modification
will occur within the staff recommendation to the hearing examiner on the Site Plan Rev iew and
Conditional Use Permit application.
A Trip Generation Memo, prepared by Transportation Engineering Northwest, dated June 27, 2022
(Exhibit 16) was submitted with the project application materials. The proposed Seattle Sounders FC
Headquarters and Training Facility project is proposing to utilize approximately 52,990 sq. ft. within the
existing Building 25-20. The Sounders would retain 21,660 sq. ft. as office use while converting 31,330 sq.
ft. of existing office use to Recreation Facilities, Indoor use. The indoor recreational facilities w ould
provide team services space, which is intended to be accessory to the office and outdoor recreation
facilities uses and would include locker rooms, training space, classrooms and workspaces, and medical
treatment rooms. The proposed project would also establish an outdoor recreational facility use with five
(5) outdoor soccer fields, a goalkeeper training area, and a maintenance shed. In addition, the proposal
would include the removal of 166 existing parking spaces.
Vehicular access to the site would remain the same, with one (1) signalized access and one (1) unsignalized
access driveway on Oakesdale Ave SW that provide access to the main parking lot on the south side of the
building, and one unsignalized access roadway that provides access to a visitor parking lot on the north
side of the building.
The weekday trip generation estimates for the office use were based on methodology documented in the
Institute of Transportation Engineers (ITE) Trip Generation Manual, 11th Edition for Land Use Code (LUC)
710 (General Office Building).
The proposed outdoor soccer training facility is not consistent with a specific land use category established
in the Institute of Transportation Engineers (ITE) Trip Generation manual. As such, project-specific
information was used for the average weekday trip generation estimates. To estimate trip generation for
the proposed Sounders training facility, the applicant provided detailed forecasts of trips anticipated to
occur on a typical weekday based on their operational plan. These weekday trip estimates are described
in the following categories:
Players/Field Use Trips – The fields are anticipated to be used daily from approximately 8:00 AM to 10:00
PM, however, not all fields will be used at the same time. The peak usage of the fields and training facility
is anticipated to occur between 10:00 AM and 1:00 PM.
Spectators Trips (Media and Public Session) – On a daily basis, it is anticipated that media and a select
number of visitors may view team practices on an invitation only basis.
Summer Camp/Clinic Trips – Summer camps run June through August and would consist of a maximum
attendance of 120 students per week, with camp/clinic hours generally between 9:30 AM and 4 PM
Monday through Thursday and between 9:30 AM and 12:00 PM on Friday.
Weekly Soccer Program Trips – The weekly soccer program consists of a skills class that would have a
maximum attendance of 50 students attending class three (3) times per week during off peak hours (i.e.
5:30 PM to 7:00 PM).
Based on the trip generation estimates discussed above, it is anticipated to the Sounders FC Center at
Longacres would generate 147 total daily trips with a reduction in AM Peak Hour trips by 9 and an increase
in PM Peak Hour trips by 14. As the proposal is not anticipated to generate 20 new AM or PM Peak Hour
trips, a Traffic Impact Analysis was not required. A Transportation Concurrency Test (Exhibit 17) was issued
for the proposal, it was concluded that the proposal passed the transportation concurrency test in
accordance with RMC 4-6-070D. It is anticipated that any new trips generated by the proposal would be
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
City of Renton Department of Community & Economic Development
Sounders FC Center at Longacres
Staff Report to the Environmental Review Committee
LUA22-000357, SA-H, CU-H, ECF, MOD
Report of November 7, 2022 Page 12 of 12
ERC_Sounders_FINAL
adequately mitigated through the payment of a Traffic Impact Fee, therefore no further mitigation is
recommended.
Mitigation Measures: None recommended
Nexus: N/A
E.Comments of Reviewing Departments
The proposal has been circulated to City Department and Division Reviewers. Where applicable, their comments
have been incorporated into the text of this report and/or “Advisory Notes to Applicant.”
✓Copies of all Review Comments are contained in the Official File and may be attached to this report.
The Environmental Determination decision will become final if the decision is not appealed within the 14-day
appeal period (RCW 43.21.C.075(3); WAC 197-11-680).
Environmental Determination Appeal Process: Appeals of the environmental determination must be filed in
writing on or before 5:00 p.m. on November 21, 2022. The City Clerk’s Office is working remotely. For that
reason, appeals must be submitted electronically to the City Clerk at cityclerk@rentonwa.gov or delivered to
City Hall 1st floor Lobby Hub Monday through Friday. The appeal fee, normally due at the time an appeal is
submitted, will be collected at a future date if your appeal is submitted electronically. Appeals to the Hearing
Examiner are governed by RMC 4-8-110 and additional information regarding the appeal process may be
obtained from the City Clerk’s Office, cityclerk@rentonwa.gov.
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521
CITY OF RENTON
DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT
STAFF REPORT TO THE ENVIRONMENTAL REVIEW COMMITTEE
EXHIBITS
Project Name:
Sounders FC Center at Longacres
Land Use File Number:
LUA22-000357, SA-H, CU-H, ECF, MOD
Date of Meeting
November 7, 2022
Staff Contact
Jill Ding
Senior Planner
Project Contact/Applicant
Julia Reeve
Unico Properties
1215 4th Ave, Suite 600,
Seattle, WA 98161
Project Location
1901 Oaksdale Ave SW, Renton,
WA 98057
The following exhibits are included with the ERC Report:
Exhibit 1: Environmental Review Committee (ERC) Report
Exhibit 2: Site Plan
Exhibit 3: Civil Plan Set
Exhibit 4: Colored Rendering
Exhibit 5: SEPA Checklist
Exhibit 6: Geotechnical Report, prepared by GeoEngineers, dated June 23, 2022
Exhibit 7: Critical Areas - Existing Conditions Letter Report prepared by Talasaea, dated April 29,
2022
Exhibit 8: Critical Areas Report and Conceptual Mitigation Plan prepared by Talasaea, dated October
7, 2022
Exhibit 9: Otak’s Peer Review Memorandum, dated June 9, 2022
Exhibit 10: Otak’s Peer Review Memorandum, dated November 2, 2022
Exhibit 11: Civil Engineering Narrative, prepared by Coughlin Porter Lundeen, dated August 8, 2022
Exhibit 12: Technical Information Report (TIR) prepared by Coughlin Porter Lundeen, dated August
2022
Exhibit 13: Arborist Report, prepared by American Forest Management, Inc., dated August 1, 2022
Exhibit 14: Lighting Plan
Exhibit 15: Public Comments
Exhibit 16: Trip Generation Memo, prepared by Transportation Engineering Northwest, dated June
27, 2022
Exhibit 17: Transportation Concurrency
Exhibit 18: Advisory Notes
Exhibit 19: Street Frontage Improvements Modification Justification
DocuSign Envelope ID: A56F3DC7-D564-4883-A9F5-21D84A1EE521