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HomeMy WebLinkAboutSR_ERC_Kennydale_Lakeline_Replacement_250918_FINALDEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT SR_ERC Report_Kennydale Lakeline Replacement Improvement Project_250917_v1 ENVIRONMENTAL REVIEW COMMITTEE REPORT ERC Meeting Date: September 22, 2025 Project File Number: PR25-000049 Project Name: Kennydale Lakeline Sanitary Sewer Improvement Project Land Use File Number: LUA25-000219, ECF, SSDP Project Manager: Alex Morganroth, Principal Planner Owner: See Exhibit 2 Applicant/Contact: Anousheh Nawaz, City of Renton / 1055 S Grady Way, Renton, WA 98057 / 425- 430-7226 / Anawaz@rentonwa.gov Project Location: 2725, 2727, 2731, 2801, 2805, 2807, 2811, 2815, 2827, 2905, 2921, 2931, 3001, 3003, 3005, 3007, 3009, 3011, 3013, 3015, 3101, 3103, 3107, 3111, 3115, 3119, 3205, 3209, 3213, 3217, 3233, 3307 Mountain View Ave N; 3401, 3405, 3411, 3501, 3601, 3605, 3607, 3611, 3613, 3619, 3625, 3703, 3707, 3709, 3711, 3713, 3715, 3717, 3719, 3805, 3811, 3815, 3821, 3825, 3827, 3837, 3901, 3905 Lake Washington Blvd N (APNs: 0523059010, 3342104050, 3342104048, 3342104046, 3342104045, 3342104040, 3342104029, 3342104010, 3342104009, 3342103985, 3342103953, 3342103942, 3342103940, 3342103941, 3342103931, 3342103930, 3342103924, 3342103920, 3342103905, 3342103906, 3342103895, 3342103890, 3342103880, 3342103860, 3342103855, 3342103845, 3342103840, 3342103810, 3342103805, 3342103795, 3342103775, 3124059077, 3124059079, 3124059076, 3124059075, 3124059074, 3124059004, 3342700355, 3342700330, 3342700320, 3342700310, 3342700300, 3342700290, 3342700280, 3224059005, 3342700270, 3342700260, 3342700250, 3342700230, 3342700240, 3342700211, 3342700200, 3342700190, 3342700176, 3342700149, 3342700126, 3342700125, 3342700110, 3342700100, 3342700080, 3342700070, 3342700011) Project Summary: The applicant is requesting State Environmental Policy Act (SEPA) review and a Shoreline Substantial Development Permit (SSDP) for the Kennydale Lakeline Sewer System Replacement Project. The project site includes multiple parcels (noted above), City of Renton right-of-way, King County Parks property, and private property located between 3905 Lake Washington Blvd N and the north end of Gene Coulon Memorial Beach Park. The existing 4,680-foot (4,680’) in-lake sewer system will be replaced with a new land-based low-pressure sewer system serving 56 properties and a public park. The proposed replacement system includes approximately 4,950 linear feet (4,950’) of new force main, 55 individual grinder pump stations, and associated electrical and utility improvements, to be constructed primarily within Mountain View Ave N and an unnamed access road east of the lake. The project will occur in two (2) phases: (1) upland construction of the new sewer system and (2) in-water decommissioning of the existing lake-line system. In-water work will be staged from barges and occur during the approved fish window (approximately July 16 to December 31). Temporary construction- related disturbance will total approximately 113,670 square feet in upland areas and 875 square feet in aquatic areas. Work would occur within and adjacent to Lake Washington, a Shoreline of the State. Shoreline designations on the site include Single-Family Residential, Urban Conservancy, and Aquatic. Work is anticipated to start in early 2026 and last up to 18 months. The project includes mitigation and restoration measures to ensure no net loss of shoreline ecological function. DocusOgn Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 City of Renton Department of Community & Economic Development Kennydale Lakeline Sanitary Sewer Improvement Project Staff Report to the Environmental Review Committee LUA25-000219, ECF, SSDP Report of September 22, 2025 Page 2 of 10 SR_ERC Report_Kennydale Lakeline Replacement_250915_DRAFT Project Location Map 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.The applicant shall submit an Inadvertent Discovery Plan (IDP) prepared by a qualified professional prior to the start of any construction. In addition, the applicant shall provide notification to Tribes’ cultural committee prior to the start of construction. Supporting documents submitted with the application includes a SEPA Checklist, Vegetation Management Plan, Geotechnical Engineering Report, Arborist Report, and Lake Study. Exist. Bldg. Area SF: N/A Proposed New Bldg. Area (footprint): Proposed New Bldg. Area (gross): N/A N/A Site Area: 100,000 square feet Total Building Area GSF (excluding buildings outside of project area): N/A STAFF RECOMMENDATION: Staff Recommends that the Environmental Review Committee issue a Determination of Non-Significance - Mitigated (DNS-M). DocusOgn Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 City of Renton Department of Community & Economic Development Kennydale Lakeline Sanitary Sewer Improvement Project Staff Report to the Environmental Review Committee LUA25-000219, ECF, SSDP Report of September 22, 2025 Page 3 of 10 SR_ERC Report_Kennydale Lakeline Replacement_250915_DRAFT C.Exhibits Exhibit 1:Environmental Review Committee (ERC) Report Exhibit 2:Project Addresses and Parcel Numbers/Property Owner List Exhibit 3:SEPA Checklist, dated May 4, 2025 Exhibit 4:Neighborhood Detail Map Exhibit 5:Project Drawings Exhibit 6:Construction Mitigation Description Exhibit 7:Geotechnical Engineering Report, prepared by Shannon & Wilson, dated December 6, 2024 Exhibit 8:Lake Study, prepared by Confluence Environmental Company, dated May 2025 Exhibit 9:Vegetation Management Plan, prepared by Confluence Environmental Company and Tree Solutions, Inc., dated May 2025 Exhibit 10:Arborist Report, prepared by Tree Solutions, Inc., dated April 15, 2025 Exhibit 11:Duwamish Tribe Comment Letter, dated July 23, 2025 Exhibit 12:City’s Email Response to the Duwamish Comment Letter, dated July 30, 2025 Exhibit 13:Department of Ecology Letter, dated August 15, 2025 Exhibit 14:City’s Email Response to the Department of Ecology Letter, dated August 15, 2025 Exhibit 15:King County Wastewater Treatment Division Letter, dated July 30, 2025 Exhibit 16:City’s Email Response to King County Wastewater Treatment Division Letter, dated July 30, 2025 Exhibit 17:Advisory Notes 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 have the following probable impacts: 1.Earth Impacts: According to City of Renton (COR) maps, the project site is located in an area identified as having a High Seismic Hazard, High Erosion Hazard, and steep slopes. As such, the applicant submitted a Geotechnical Engineering Report prepared by Shannon & Wilson, dated December 6, 2024 (Exhibit 7). The report states that the project area contains a range of soil and geologic conditions associated with glacial and post-glacial deposits along the eastern shoreline of Lake Washington. Subsurface explorations advanced between 15.5 feet and 25.9 feet (15.5’ – 25.9’) deep encountered fill, Holocene deposits, recessional outwash, lacustrine deposits, dense glacial till, and glacially overridden pre-Vashon deposits. The report notes that shallow perched groundwater was encountered between three feet and fifteen feet (3’ and 15’) below ground surface in several borings, with seasonal fluctuations expected. Vibrating wire piezometers installed at the site continue to monitor groundwater elevations. The conditions contribute to mapped erosion hazard and steep slope areas along the project alignment. DocusOgn Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 City of Renton Department of Community & Economic Development Kennydale Lakeline Sanitary Sewer Improvement Project Staff Report to the Environmental Review Committee LUA25-000219, ECF, SSDP Report of September 22, 2025 Page 4 of 10 SR_ERC Report_Kennydale Lakeline Replacement_250915_DRAFT The submitted report also evaluated seismic hazards. The project corridor is located approximately three (3) to four (4) miles south of the Seattle Fault zone. Based on the 2021 IBC and ASCE 7-16 standards, the site is classified as Seismic Site Class D, with a peak ground acceleration of 0.619g, a short-period spectral response acceleration (Ss) of 1.45g, and a one-second spectral response acceleration (S1) of 0.50g. Liquefaction potential across the corridor was assessed as low to moderate. While perched groundwater within loose recessional deposits could present localized liquefaction risk, the report concludes that the proposed generator foundation site is unlikely to be affected because groundwater was not encountered within loose soil layers at that location. A slope stability analysis was performed near the proposed generator site at the north end of the alignment, where the facility will be situated above a 10-foot (10’) slope that descends toward Lake Washington Blvd N. The report found that the slope is stable under static undrained conditions and marginally stable under seismic conditions. However, under long-term drained conditions, the factor of safety was calculated at 0.8, indicating instability. The submitted report recommends additional survey work to refine slope geometry and design of stabilization measures, such as retaining structures or reinforced foundations, to ensure long-term stability prior to generator installation. Construction of the upland sewer alignment will require extensive trenching, with the report anticipating approximately 9,562 cubic yards of excavation and fill. Trenchless construction may be used for some laterals to reduce surface disturbance, but open trench excavation is expected for the majority of the force main. According to the submitted report, excavation and dewatering in areas with perched groundwater could mobilize fine sediments and increase erosion risk if not properly managed. The geotechnical engineer provides detailed recommendations for excavation, shoring, trench backfill, and compaction, which are necessary to prevent settlement and maintain slope stability during and after construction. In-water work is limited to the removal of three (3) manholes, excavation of approximately 33 cubic yards of lakebed material, and placement of about 39 cubic yards of gravel for habitat restoration (Exhibit 5). The report indicates that these limited excavation activities are not expected to destabilize the lakebed, but erosion and sediment control measures will be required to minimize turbidity during barge operations. In conclusion, based on the findings of the submitted Geotechnical Engineering Report, the project will temporarily disturb slopes, soils, and groundwater conditions along the alignment. With implementation of the recommended construction methods, slope stabilization measures, and erosion and sediment control best management practices, no long-term geologic or soil-related impacts are anticipated. Staff finds that removal of the in-lake infrastructure and relocation of the sewer system to upland areas will ultimately reduce the potential for lakebed scour or sediment release, thereby improving long-term geologic stability and reducing risk to Lake Washington. Therefore, no additional site-specific mitigation measures are proposed. Mitigation Measures: None recommended. Nexus: Not applicable. 2.Air Impacts: It is anticipated that some temporary air quality impacts could be associated with the site work that is anticipated to begin in 2026 and end in 2027 or 2028 once the upland replacement system is installed. Project development impacts during construction may include dust and exhaust from construction equipment, barges, boats, generators, or other vehicles and equipment used to install a land-based sewer system and in-water construction to decommission the existing lakeline system. Dust control would be mitigated through the use of temporary erosion control measures, wattle installation, plastic covering installation, seeding, mulching, or other measures to remediate DocusOgn Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 City of Renton Department of Community & Economic Development Kennydale Lakeline Sanitary Sewer Improvement Project Staff Report to the Environmental Review Committee LUA25-000219, ECF, SSDP Report of September 22, 2025 Page 5 of 10 SR_ERC Report_Kennydale Lakeline Replacement_250915_DRAFT impacts as needed. Minimal emissions are expected from the maintenance and operation of the sanitary sewer system when the project is completed. No further site-specific mitigation for the identified impacts from typical vehicle and construction exhaust is required. Mitigation Measures: None recommended. Nexus: Not applicable. 3. Water a. Wetland, Streams, Lakes Impacts: The Kennydale Lakeline Sewer System Replacement Project is located directly along, and partially within, Lake Washington, which is classified as a Shoreline of the State under the Shoreline Management Act. As such, the applicant submitted a Lake Study prepared by Confluence Environmental Company, dated May 2025 (Exhibit 8). Shoreline designations within the project corridor include Single-Family Residential, Urban Conservancy, and Aquatic. The lake has been altered significantly over the past century and the development along the shoreline has contributed to loss of habitat primarily due to new overwater structures, removal of riparian vegetation and large woody debris, and an increase in shoreline armoring. However, Lake Washington continues to be a critical natural resource that provides important ecological functions, including fish migration, rearing, and foraging habitat for several ESA-listed salmonid species such as Chinook salmon, steelhead trout, and bull trout. Resident fish including sockeye salmon, coho salmon, and cutthroat trout are also present. The lake supports sockeye spawning in this reach and the Lake Study prepared for the project identifies specific spawning areas that will be protected and enhanced through habitat restoration following in-water work. The existing lakeline sewer system was constructed in 1972 and consists of approximately 4,680 feet (4,680’) of sewer main placed offshore, three (3) manholes, and a flush station intake. The infrastructure lies within about 50 feet (50’) of the shoreline in water depths ranging from six to twenty feet (6-20’). Decommissioning the system requires direct work below the ordinary high-water mark (OHWM), including removal of the manholes, abandonment of the sewer line, and dismantling of the flush station intake structure. Once cleaned, the pipe will be filled with water to prevent collapse and to avoid the risks associated with controlled density fill entering the lake. According to the Vegetation Management Plan, prepared by Confluence Environmental Company and Tree Solutions, Inc., dated May 2025 (Exhibit 9), the removal of the manholes will disturb approximately 33 cubic yards of material, which will be backfilled with gravel designed to provide appropriate substrate for juvenile salmonid rearing and sockeye spawning. In total, approximately 39 cubic yards of gravel will be placed in the lakebed, providing a long-term ecological benefit in the form of improved habitat complexity. Upland construction will also take place within the shoreline jurisdiction. The new force main alignment, grinder pump stations, and laterals will be located within Mountain View Ave N right-of- way (ROW) and King County Parks property just east of the lakeshore (Exhibits 4 and 5). Approximately 113,670 square feet of temporary upland disturbance will occur within 200 feet (200’) of the OHWM. Vegetation along the corridor is fragmented, consisting of landscaped residential yards interspersed with larger black cottonwood and bigleaf maple trees along the East Rail Trail and public lands. The Arborist Report, prepared by Tree Solutions, Inc., dated April 15, 2025 (Exhibit 10), identified 308 trees within or adjacent to the project area, most of which were planted as part of residential landscaping. Depending on the construction method, tree removal could range from four (4) (trenchless installation) to twenty-one (21) (open trench installation) trees. According to the applicant, the project proposes to minimize removal through trenchless techniques wherever feasible, and all removals will be mitigated with replacement trees as required by RMC 4-4-130. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 City of Renton Department of Community & Economic Development Kennydale Lakeline Sanitary Sewer Improvement Project Staff Report to the Environmental Review Committee LUA25-000219, ECF, SSDP Report of September 22, 2025 Page 6 of 10 SR_ERC Report_Kennydale Lakeline Replacement_250915_DRAFT Ecological functions within the riparian zone are limited by the degree of existing urbanization, shoreline armoring, and the prevalence of non-native landscaping. However, the Lake Study notes that even fragmented vegetation provides important ecological services such as shading, organic matter input, and wildlife cover. The Lake Study concluded that tree removal and upland disturbance would result in localized and temporary reductions in riparian function, but these impacts will be fully mitigated through replacement planting and vegetation restoration under the project’s Vegetation Management Plan. As a result, no long-term loss of ecological function is anticipated. Lake Washington itself has been extensively modified by urban development over the past century. Shoreline armoring, removal of large woody debris, and stormwater inputs have degraded habitat complexity throughout the lake. Within the project corridor, riparian and aquatic habitats remain moderately functional, supporting fish passage, limited rearing habitat, and bird foraging. The Lake Study documented the continued use of this reach by salmonids and identified restoration opportunities associated with the sewer decommissioning. Importantly, the project will remove failing in-lake infrastructure that currently poses a risk of leakage and sediment disturbance, thereby improving long-term water quality and aquatic habitat conditions. To minimize construction-related impacts, the applicant proposes to limit all in-water work to the Washington Department of Fish and Wildlife approved fish window of July 16th through December 31st, when fish are least vulnerable to disturbance. In-water work is expected to take approximately six (6) weeks and would occur in the first half of the fish window (Exhibit 6). Additional best management practices will be implemented to prevent turbidity and sedimentation during barge operations and manhole removal. For upland work, erosion and sediment control measures will be required in accordance with the 2022 Renton Surface Water Design Manual. Together, the report notes, the proposed measures ensure compliance with local, state, and federal requirements for shoreline protection. The Lake Study concludes the project will temporarily impact Lake Washington and its riparian zone through vegetation removal, ground disturbance, and limited in-water excavation. However, the combination of proposed mitigation measures, including tree replacement, vegetation restoration, gravel placement in spawning areas, and strict adherence to fish window and erosion control requirements, will offset these impacts and provide ecological improvements. Consistent with the findings of the Lake Study, staff concurs that the project will achieve the City’s no net loss standard under RMC 4-3-090D.2 and will not result in significant adverse impacts to Lake Washington, its shoreline, or associated fish and wildlife habitat. Therefore, no additional site-specific mitigation measures are proposed. Mitigation Measures: None recommended. Nexus: Not applicable. 4. Plants Impacts: According to the submitted Arborist Report, prepared by Tree Solutions, Inc., dated April 15, 2025 (Exhibit 10) and the Vegetation Management Plan (Exhibit 9), prepared by Confluence Environmental Company and Tree Solutions, Inc., dated May 2025, the project will result in the removal of a limited number of trees and disturb landscaped vegetation within the shoreline jurisdiction. The upland work will result in temporary disturbance of approximately 113,670 square feet of landscaped yards, roadway right-of-way, and public park areas. Vegetation removed will consist primarily of lawn, ornamental shrubs, and other landscaping associated with existing single- family residences. No intact native forest stands will be cleared. The Arborist Report identifies a total of 308 trees within or adjacent to the project corridor. Depending on the construction method used, the project could result in removal of between four (4) and twenty- Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 City of Renton Department of Community & Economic Development Kennydale Lakeline Sanitary Sewer Improvement Project Staff Report to the Environmental Review Committee LUA25-000219, ECF, SSDP Report of September 22, 2025 Page 7 of 10 SR_ERC Report_Kennydale Lakeline Replacement_250915_DRAFT one (21) significant trees, with thirteen (13) additional trees potentially impacted within their critical root zones. If trenchless construction methods are utilized for grinder pump laterals, only four (4) significant trees would be removed. If open trench methods are required, up to twenty-one (21) significant trees would be removed. These removals are outside of critical areas and buffers but within the shoreline jurisdiction. No listed or priority plant species were observed within the project area. Replacement of significant trees is required under City of Renton regulations, primarily RMC 4-4- 130H.1. The Vegetation Management Plan provides details on the location and type of restoration for each disturbed area. Replacement will occur at a minimum ratio of 1:1, using native species wherever feasible, with landscaped species replanted where requested by property owners. Due to limited available planting space on some private parcels, the appropriate number of replacement trees will be installed at approved off-site locations. The Vegetation Management Plan also establishes a comprehensive restoration program. Disturbed areas on private property will be restored in-kind with existing lawn or ornamental vegetation, while areas within Kennydale Beach Park will be replanted with native shrubs and understory species such as tall Oregon grape, Nootka rose, snowberry, kinnikinnick, and beach strawberry. Temporary and permanent seeding will be used to stabilize soils and reduce erosion. Native vegetation will be preserved where practicable, particularly on steep slopes and near perennial and intermittent swales, to minimize erosion and maintain site stability. The Vegetation Management Plan sets performance standards to ensure successful restoration, including 100 percent (100%) survival of planted trees in the first year, 80 percent (80%) survival of shrubs and groundcover by the second year, increasing native cover to at least 50 percent (50%) by Year 3, and maintaining invasive species at less than 10 percent (10%) cover. A three-year monitoring and maintenance program will include transects, permanent photo points, and annual reporting to the City. Contingency measures are identified for plant mortality, lack of native cover, or invasive species infestation. With respect to invasive vegetation, the Arborist Report and Vegetation Management Plan identifies Himalayan blackberry (Rubus armeniacus), English ivy (Hedera helix), and reed canarygrass (Phalaris arundinacea) as common upland invasive species within the project area. The Vegetation Management Plan proposes their removal within disturbed areas and replanting with native species. In addition, common non-native aquatic plants such as Eurasian watermilfoil, hydrilla, elodea, and water hyacinth are present in Lake Washington. While in-water excavation is expected to occur outside of vegetated beds, the potential presence of these species is noted, and best management practices will be implemented to avoid their spread. In conclusion, the project will result in removal of between four (4) and twenty-one (21) significant trees and disturbance to landscaped vegetation along the shoreline. These impacts are temporary and will be mitigated through implementation of the Vegetation Management Plan and Arborist Report recommendations, including tree replacement, invasive species removal, and a multi-year monitoring program. No listed or priority plant species are known to occur on or near the site. With these measures in place, staff finds the project will not result in a net loss of shoreline vegetation function and will comply with the requirements of RMC 4-3-090 and 4-4-130. Therefore, no site- specific mitigation is recommended. Mitigation Measures: None recommended. Nexus: Not applicable. 5. Animals Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 City of Renton Department of Community & Economic Development Kennydale Lakeline Sanitary Sewer Improvement Project Staff Report to the Environmental Review Committee LUA25-000219, ECF, SSDP Report of September 22, 2025 Page 8 of 10 SR_ERC Report_Kennydale Lakeline Replacement_250915_DRAFT Impacts: According to the submitted Lake Study (Exhibit 8), the project area along Lake Washington provides habitat for a wide variety of terrestrial and aquatic species. Bird species observed on and near the site include bald eagle (Haliaeetus leucocephalus), red-tailed hawk (Buteo jamaicensis), mallard (Anas platyrhynchos), common merganser (Mergus merganser), bufflehead (Bucephala albeola), belted kingfisher (Megaceryle alcyon), great blue heron (Ardea herodias), American goldfinch (Spinus tristis), Wilson’s warbler (Cardellina pusilla), and northern flicker (Colaptes auratus). An osprey nest has been identified approximately 1,000 feet (1000’) north of May Creek, and bald eagle nests are present at the south end of Mercer Island. A bald eagle was observed perched in a mature conifer at 3827 Mountain View Ave N, and a landowner at 3009 Mountain View Ave N reports regular eagle foraging in the area. These observations confirm that the project area supports migratory and resident bird species that rely on shoreline vegetation and aquatic resources for foraging and cover. Mammals have also been documented within and adjacent to the project area, including mule deer (Odocoileus hemionus), eastern cottontail (Sylvilagus floridanus), North American river otter (Lontra canadensis), and eastern gray squirrel (Sciurus carolinensis). These species primarily use riparian corridors, landscaped areas, and Lake Washington itself for foraging. No reptiles or amphibians were observed during surveys, although the Lake Study notes that small terrestrial amphibians and reptiles common to the Lake Washington basin could use the area intermittently. The Lake Study notes that the aquatic environment of Lake Washington is of particular ecological importance. Fish species observed in and near the site include common sunfishes (Lepomis spp.), freshwater sculpins (Cottus spp.), yellow perch (Perca flavescens), and threespine stickleback (Gasterosteus aculeatus) (WDFW 2025). More critically, the site is used by multiple ESA-listed salmonids, including Chinook salmon (Oncorhynchus tshawytscha), steelhead trout (Oncorhynchus mykiss), and bull trout (Salvelinus confluentus), as well as resident sockeye (Oncorhynchus nerka), coho (O. kisutch), and cutthroat trout (O. clarkii). The Lake Study documents that this reach of Lake Washington supports sockeye spawning, with suitable substrate and water depths present near the existing manholes. The project will temporarily disturb approximately 875 square feet of aquatic habitat during removal of the three (3) manholes and related decommissioning work. According to the Lake Study, this disturbance will be offset by placement of approximately 39 cubic yards of spawning gravel, which is expected to enhance sockeye habitat in the project reach. In-water work will occur only during the Washington Department of Fish and Wildlife’s approved fish window (July 16 to December 31), thereby minimizing potential conflicts with fish migration and spawning. Additional best management practices include installation of turbidity curtains to isolate the in-water work area and exclude fish from construction zones, thereby reducing exposure to turbidity and construction noise. While no listed plant species are known to occur within the project corridor, invasive animal species are known from Lake Washington and its tributaries, including New Zealand mud snail (Potamopyrgus antipodarum), oriental weatherfish (Misgurnus anguillicaudatus), walleye (Sander vitreus), and northern pike (Esox lucius). Although no site-specific surveys were conducted for invasive fauna, the project’s limited in-water footprint and adherence to BMPs are not expected to increase the spread of invasive animal species. In summary, the project area supports a diverse community of birds, mammals, and aquatic species, including several ESA-listed fish. Construction activities will cause short-term disturbance, including noise, turbidity, and localized habitat impacts, but these will be mitigated through fish window timing, use of turbidity curtains, erosion control measures, and gravel placement for spawning enhancement. Based on the submitted Lake Study and supporting SEPA documentation, staff finds that the project will not result in significant adverse impacts to fish or wildlife populations and will comply with the “no net loss” standard under RMC 4-3-090D.2. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 City of Renton Department of Community & Economic Development Kennydale Lakeline Sanitary Sewer Improvement Project Staff Report to the Environmental Review Committee LUA25-000219, ECF, SSDP Report of September 22, 2025 Page 9 of 10 SR_ERC Report_Kennydale Lakeline Replacement_250915_DRAFT Mitigation Measures: None recommended. Nexus: Not applicable. 6.Environmental Health a.Hazards Impacts: A representative of the Washington State Department of Ecology (DOE) submitted a comment (Exhibit 13) on August 15, 2025 noting that the project area includes a known cleanup site, the Marshall Residence (Ecology Facility ID 84152951), which is suspected to be contaminated with petroleum, metals, and polycyclic aromatic hydrocarbons (PAHs). In the comment, DOE requests that the City and applicant notify Ecology immediately if contamination is encountered during project construction and coordinate directly with the agency to ensure proper management and cleanup. Staff notes that the SEPA checklist (Exhibit 3) already identifies the presence of this cleanup site within the project corridor, but additional measures are necessary to ensure that potential soil or groundwater contamination is handled appropriately. City staff is aware of the need to notify DOE if contamination is encountered and therefore no site-specific mitigation is recommended. Mitigation Measures: None recommended. Nexus: Not applicable. b.Noise Impacts: Noise impacts would primarily result from equipment and activity associated with open- trench excavation to install sanitary sewer lines and ILS systems and potentially from trenchless methods if used. In addition, noise impacts would also occur as a result of vehicles, boat engines, motors for pipeline cleaning, and equipment used to remove manholes from the lakeline. The construction noise would be regulated through the city’s adopted noise level regulations per Chapter 8-7, RMC. The city’s noise regulations limit haul hours between eight-thirty (8:30) am to three-thirty (3:30) pm, Monday through Friday, unless otherwise approved by the Development Services Division. Permitted work hours in or near residential areas are restricted to the hours between seven o’clock (7:00) a.m. and eight o’clock (8:00) p.m. for nonresidential construction activities from Monday through Friday. Work on Saturdays is restricted to the hours between nine o’clock (9:00) a.m. and eight o’clock (8:00) p.m. No work is permitted on Sundays. All noise levels would be required to comply with City of Renton code (Chapter 7, Noise Level Regulations) and Washington Administrative Code (WAC 173-60, Maximum Environmental Noise Levels). The anticipated temporary noise impacts would be those commonly associated with utility construction. No further site-specific mitigation is proposed. Mitigation Measures: None recommended. Nexus: Not applicable. 7.Historic and Cultural Preservation Impacts: A representative of the Duwamish Tribe submitted a comment letter (Exhibit 11) to city staff on July 23, 2025 indicating the project site is located in an area that the Tribe considers culturally significant with a high probability of having unknown archaeological deposits. In addition, the Washington Department of Archaeology and Historic Preservation WISAARD mapping tool indicates a high to very high potential for encountering cultural resources. The Tribe also requests the applicant plant only native vegetation and trees for replacement in the project area. Staff notes that the Vegetation Management Plan includes a proposal for the establishment of native vegetation where possible. In order to ensure contractors working on the project have instructions regarding steps to take if cultural resources are discovered, staff recommends as a mitigation measure that DocusOgn Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 City of Renton Department of Community & Economic Development Kennydale Lakeline Sanitary Sewer Improvement Project Staff Report to the Environmental Review Committee LUA25-000219, ECF, SSDP Report of September 22, 2025 Page 10 of 10 SR_ERC Report_Kennydale Lakeline Replacement_250915_DRAFT the applicant prepare and submit an Inadvertent Discovery Plan (IDP) prior to the start of any construction. In addition, the applicant shall provide notification to Tribes’ cultural committee prior to the start of construction. Mitigation Measures: The applicant shall submit an Inadvertent Discovery Plan (IDP) prepared by a qualified professional prior to the start of any construction. In addition, the applicant shall provide notification to Tribes’ cultural committee prior to the start of construction. Nexus: City of Renton Comprehensive Goals and Policies, L-AA, L-44 and L-45; Chapter 27.53 RCW, Archaeological Sites and Resources; Chapter 27.44 RCW, Indian Graves and Records; Chapter 197- 11 WAC, SEPA Rules; and Duwamish Tribe Comment, dated July 23, 2025. 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 October 7, 2025. 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. The appeal submitted in person may be paid on the first floor in our Finance Department. 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. DocusOgn Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 CITY OF RENTON DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT STAFF REPORT TO THE ENVIRONMENTAL REVIEW COMMITTEE EXHIBITS Project Name: Kennydale Lakeline Replacement Project Land Use File Number: LUA25-000219, ECF, SSDP Date of Meeting September 22, 2025 Staff Contact Alex Morganroth Principal Planner Project Contact/Applicant Anousheh Nawaz, City of Renton / 1055 S Grady Way, Renton, WA 98057 / 425-430- 7226 / Anawaz@rentonwa.gov Project Location Lake Washington Shoreline (see Exhibit 2) The following exhibits are included with the ERC Report: Exhibit 1:Environmental Review Committee (ERC) Report Exhibit 2:Project Addresses and Parcel Numbers/Property Owner List Exhibit 3:SEPA Checklist, dated May 4, 2025 Exhibit 4:Neighborhood Detail Map Exhibit 5:Project Drawings Exhibit 6:Construction Mitigation Description Exhibit 7:Geotechnical Engineering Report, prepared by Shannon & Wilson, dated December 6, 2024 Exhibit 8:Lake Study, prepared by Confluence Environmental Company, dated May 2025 Exhibit 9:Vegetation Management Plan, prepared by Confluence Environmental Company and Tree Solutions, Inc, dated May 2025 Exhibit 10:Arborist Report, prepared by Tree Solutions, Inc, dated April 15, 2025 Exhibit 11:Duwamish Tribe Comment Letter, dated July 23, 2025 Exhibit 12:City’s Email Response to the Duwamish Comment Letter, dated July 30, 2025 Exhibit 13:Department of Ecology Letter, dated August 15, 2025 Exhibit 14:City’s Email Response to the Department of Ecology Letter, dated August 15, 2025 Exhibit 15:King County Wastewater Treatment Division Letter, dated July 30, 2025 Exhibit 16:City’s Email Response to King County Wastewater Treatment Division Letter, dated July 30, 2025 Exhibit 17:Advisory Notes DocusOgn Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124