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HomeMy WebLinkAboutCL_SEPAChecklist_2505.pdfSEPA Environmental checklist May 2025 Page 1 (WAC 197-11-960) SEPA 1 Environmental Checklist Purpose of checklist Governmental agencies use this checklist to help determine whether the environmental impacts of your proposal are significant. This information is also helpful to determine if available avoidance, minimization, or compensatory mitigation measures will address the probable significant impacts or if an environmental impact statement will be prepared to further analyze the proposal. Instructions for applicants This environmental checklist asks you to describe some basic information about your proposal. Please answer each question accurately and carefully, to the best of your knowledge. You may need to consult with an agency specialist or private consultant for some questions. You may use “not applicable” or “does not apply” only when you can explain why it does not apply and not when the answer is unknown. You may also attach or incorporate by reference additional studies reports. Complete and accurate answers to these questions often avoid delays with the SEPA process as well as later in the decision-making process. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. Attach any additional information that will help describe your proposal or its environmental effects. The agency to which you submit this checklist may ask you to explain your answers or provide additional information reasonably related to determining if there may be significant adverse impact. Instructions for lead agencies Please adjust the format of this template as needed. Additional information may be necessary to evaluate the existing environment, all interrelated aspects of the proposal and an analysis of adverse impacts. The checklist is considered the first but not necessarily the only source of information needed to make an adequate threshold determination. Once a threshold determination is made, the lead agency is responsible for the completeness and accuracy of the checklist and other supporting documents. Use of checklist for nonproject proposals For nonproject proposals (such as ordinances, regulations, plans and programs), complete the applicable parts of sections A and B, plus the Supplemental Sheet for Nonproject Actions (Part D). Please completely answer all questions that apply and note that the words "project," "applicant," and "property or site" should be read as "proposal," "proponent," and "affected geographic area," respectively. The lead agency may exclude (for non- projects) questions in “Part B: Environmental Elements” that do not contribute meaningfully to the analysis of the proposal. 1 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/Checklist-guidance SEPA Environmental checklist May 2025 Page 2 (WAC 197-11-960) A. Background Find help answering background questions2 1. Name of proposed project, if applicable: Kennydale Lakeline Sewer System Replacement Project 2. Name of applicant: City of Renton, Utility Systems Division – Joe Stowell 3. Address and phone number of applicant and contact person: Address: 1055 S Grady Way, Renton, WA 98057 Phone: (425) 430-7212 Contact Person: Joe Stowell, City of Renton: Utilities Systems Division 4. Date checklist prepared: May 4, 2025 5. Agency requesting checklist: City of Renton, Utility Systems Division 6. Proposed timing of schedule (including phasing, if applicable): Construction for the Kennydale Lakeline Sewer System Replacement Project is scheduled to start in early 2026 and will be split into the following phases: (1) upland construction to install a land-based sewer system followed by (2) in-water construction to decommission the existing lakeline system. The anticipated duration of construction for Phase 1 is approximately 18 months, although the construction schedule will be finalized during final design. It is estimated that the majority of work on each private property will take approximately 1 to 2 weeks. The duration could be longer depending on conditions during construction. Once the replacement system is complete (i.e., Phase 1), the existing Kennydale lakeline system will be decommissioned. Lakeline decommissioning is scheduled to occur in 2027 or 2028 once the upland replacement system is installed. Decommissioning work will occur during approved in water work window for Lake Washington (July 16-December 31) and is expected to take approximately 6 weeks to complete. The anticipated timing is between July 16 and September 30, but could shift depending on construction needs. 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. No future additions or expansions related to this proposal would occur. Maintenance will be performed on the new sewer system as needed. 2 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-A-Background SEPA Environmental checklist May 2025 Page 3 (WAC 197-11-960) 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. An environmental conditions report characterizing the Lake Washington habitats above and adjacent to the existing Kennydale Lakeline Sewer System (lakeline system or Kennydale lakeline system) was completed in April 2017 (Confluence 2017). Additionally, a physical inspection along the lakeline system was completed the City of Renton (the City) between July 16, 2018, and September 30, 2018. The 2018 inspection was conducted to evaluate pipeline conditions at up to 13 locations. Condition evaluation included ultrasonic thickness testing, collection of pipeline coupons, and temporary access at several existing in-water manholes for lakeline system cleaning. Since the condition evaluation was conducted, a decision was made to move forward with an upland grinder pump solution to replace the Kennydale lakeline system. The following environmental documents were used to inform relevant SEPA elements, including: • Project Drawings (Carollo 2025) • Biological Evaluation (BE) for compliance under Section 7 of the federal Endangered Species Act (ESA) for federal permitting (Shannon and Wilson 2024) • Project Narrative and Code Consistency Analysis (Confluence 2025a) • Joint Aquatic Resource Permit Application (JARPA) • Archaeological Survey Report: Kennydale Lakeline Sewer System Improvement Project, Renton, King County, Washington (Bush et al. 2024) • Lake Study for compliance with the City of Renton Critical Areas Ordinance and Shoreline Master Program (Confluence 2025b) • Vegetation Management Plan (Confluence and Tree Solutions 2025) • Draft Geotechnical Report (Shannon and Wilson 2024) 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. There are various permit submitted by private residence for work on their property, but no permits related to the proposed sewer system. No other proposals related to the action or proposals that would impact the proposed project are pending government approval. 10. List any government approvals or permits that will be needed for your proposal, if known. • U.S. Army Corps of Engineers (Corps): o Section 10 of the Rivers and Harbors Act o Section 404 of the Clean Water Act o Section 106 of National Historic Preservation Act • National Marine Fisheries Service and U.S. Fisheries and Wildlife Service (USFWS): o ESA Section 7 Consultation SEPA Environmental checklist May 2025 Page 4 (WAC 197-11-960) • Washington Department of Ecology (Ecology): o Section 401 of the Clean Water Act o Construction Stormwater General Permit • Washington Department of Fish and Wildlife (WDFW): o Hydraulic Project Approval • City of Renton: o Land Use/ Critical Areas permit o Substantial Shoreline Development Permit (SSDP) o Grading Permit o Right-of-Way (ROW) Use Permit 11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. (Lead agencies may modify this form to include additional specific information on project description.) The purpose of this project is to provide a reliable and easily maintainable sewer service to Renton shoreline residences that integrates with the existing sewer conveyance and pumping system and that has the least aquatic environmental impact possible. This project is needed because the existing lakeline system that was installed in Lake Washington in 1972 is reaching the end of its useful life and is unable to be maintained in its current location. The Kennydale lakeline system was constructed in 1972 to provide sanitary sewer service to 56 residences and 1 park along Lake Washington from the north end of Gene Coulon Memorial Beach Park to just south of May Creek. The lakeline system consists of a flush station, an 8-inch cast iron sewer pipe buried offshore in Lake Washington, 3 manholes, and a system of 37 gravity side sewer laterals connecting customers to sewer treatment. The Lake Washington No. 2 lift station pumps the flow from the lakeline system (in addition to flow from the basin to the north) to the King County Eastside Interceptor, the regional conveyance system to South Plant, where it is treated. The Kennydale lakeline system is a low-pressure system that operates by collecting fresh lake water via an intake pipe at the flush station located at the north end of Gene Coulon Park and pumping water through the line to convey wastewater collected by the lateral connections to the Lake Washington No. 2 lift station at the north end of the lakeline near North 40th Street. The initial 300 feet of the lakeline system is onshore and the rest is predominantly buried below the lakebed, within approximately 50 feet of the shoreline. The lakeline system has an undulating profile, with high and low points that prevent full evacuation of wastewater. The City has come to the conclusion that the existing lakeline system needs to be replaced with a land-based individual lift station (ILS) sewer system based on results from a 2018 assessment, cleaning and maintenance attempts, participation in the in-water sewer SEPA Environmental checklist May 2025 Page 5 (WAC 197-11-960) workgroup, environmental and permitting considerations, and evaluation of numerous alternatives. Kennydale Lakeline Sewer System Replacement Project is being designed and permitted per applicable regulatory requirements and will occur in the following two phases: (1) upland construction to install a land-based sewer system, followed by (2) in- water construction to decommission the existing lakeline system. Phase 1 Phase 1 of the project, construction for the land-based sewer system, will potentially use a combination of open-trench excavation and trenchless technologies. Both methods are described below, although project impacts are based on assuming open-trench excavation for the entire project. If trenchless methods are used, then project impacts will be reduced. The City will own and maintain the new sewer system including the individual grinder pumps. The City will use existing easements or negotiate access agreements with each property owner to provide for the routine maintenance of the grinder pumps as well as emergency access in the event of a pump failure. Grinder Pump Installation Each ILS will be a prefabricated grinder pump unit manufactured by E-One (or equivalent) and includes a buried basin connected to a discharge lateral to receive wastewater flow. Each discharge lateral will connect the ILS to the force main in the public roadway. Each ILS with grinder pumps will have an above-ground local control panel within approximately 20 feet. A conduit for power and control signal communications will be installed between the control panel and the ILS. The power will also extend to the control panel from the proposed electrical distribution system in the adjacent roadways. In general, ILS with grinder pumps will be installed on the lake side of the houses within an excavated 50 to 100 square feet (SF) area for a total of 55 locations. Excavation within private properties may require a mini-excavator, vacuum excavator truck, high-pressure water knife, and dump truck. For each ILS, a discharge lateral and an electrical service line will be installed from the roadways across private property. Once the ILS is operational, the gravity sewer line from the house will be rerouted from the existing lakeline side sewer lateral to the ILS. The existing lakeline side sewer will be permanently abandoned onshore. Open Trench Excavation The force main will be installed using open-cut trench methods of construction. The contractor has been given the choice of using open-cut or trenchless methods for installation of the laterals, but for the purposes of permitting the maximum potential impacts, open-cut lateral installation is assumed. Open-cut methods consist of excavating from the surface to form a trench or structure excavation. Trenching typically requires an excavator, dump truck, loader, and dozer. A vibratory hammer or other compaction equipment will be required for compaction of trench backfill. The following open-cut trenching methods are anticipated for excavation: • A mini-excavator may be used for trenching where access permits. The geotechnical report noted the presence of glacial conditions (Shannon and Wilson 2024), meaning that gripper teeth will likely be needed where excavators are used. SEPA Environmental checklist May 2025 Page 6 (WAC 197-11-960) • Vacuum excavation may be used for trenching where access is more limited. Hose extensions can enable vacuum excavation up to approximately 150 feet from the vacuum excavation truck and up to a depth of 15 feet at that range. When this method is used in combination with a high-pressure water knife, harder glacial soils can be disturbed and removed by the vacuum. Vacuum excavation is less likely to cause damage to other existing utilities than other open cut methods. • Hand digging may be used where access limitations or distance from the roadway prevent the use of a mini-excavator or vacuum excavation. Dewatering may be required, depending on the groundwater elevation and the depth of excavation. If dewatering occurs, it will require a sedimentation tank to be used on-site. However, space constraints may limit the use of typical 18-foot long tanks. Trenchless Installation To reduce restoration cost and disruption to residents, trenchless methods for the installation of the laterals and electrical service to the grinder pump stations are preferred. This includes crossing concrete driveways or other concrete paved areas, areas with limited space for trenching between houses, and areas of detailed landscaping that would be difficult to restore. The contract documents specify trenchless lateral installation where feasible. However, for permitting purposes, open cut installation is assumed for all laterals, to capture the maximum potential amount of surface disturbance/impacts. Based on the geotechnical explorations (Shannon and Wilson 2024), the project area is conducive to horizontal directional drilling (HDD). HDD includes advancing a pilot bore from the roadway side of the property to the side or back yard. The pilot bore will then be incrementally expanded (reamed) to a size large enough for pipe installation (pullback). Mini HDD drilling systems (such as a “Ditch Witch”) are particularly suited to this application given the limited available working room. The launching and receiving pit of the HDD may require temporary excavation support and dewatering. The work area will be temporarily supported and dewatered (as necessary) using a contractor-proposed system that will be reviewed and approved by the appropriate regulatory authorities. Where soil conditions require use of drilling mud for hole stability, care will be needed to avoid inadvertent fluid release or “frac-outs,” in which drilling mud migrates from the bore to the surface or other unintended location. A contractor contingency plan for remediation is a recommended requirement. The contractor will be required to submit a work plan for each onsite installation prior to commencing work. Restoration and Cleanup After construction of the ILS, all construction equipment will be removed as soon as practicable once construction activities are completed. Temporarily affected areas will be restored in-kind to existing conditions. Vegetation will be replaced at a 1:1 ratio using native species or replacing landscaped species. There is also a total of 4 significant trees that will SEPA Environmental checklist May 2025 Page 7 (WAC 197-11-960) be removed outside of critical areas or buffers. The replacement of significant trees will be at a ratio of at least 1:1. A Vegetation Management Plan (Confluence and Tree Solutions 2025) provides details on the location and type of restoration for each area that is disturbed. In some sections, the entire road base and subbase will be reconstructed (rather than trench repair or overlays), and the asphalt surface will be reprofiled to better manage surface water runoff. Asphalt overlay may be required in other parts of the roadway in addition to a trench patch, depending on the location of the trench patch and the jurisdiction of the roadway. Refer to Permit Drawings for the roadway repair layout provided under a separate cover. Phase 2 Phase 2 of the project is decommissioning the existing Kennydale lakeline system, which is located approximately 50 feet from the Lake Washington ordinary high water mark (OHWM) and runs primarily parallel from south of Coleman Point to the northernmost house on the existing lakeline at 3901 Lake Washington Boulevard N. The pipeline is a total of 4,680 LF, with 37 gravity side sewer laterals (2 laterals at the Kennydale Beach Park), 3 manholes, a flush station, and a lift station along the length. The shoreline in the vicinity of the lakeline system corridor is entirely developed. Development primarily consists of private residential properties with the exception of the Kennydale Beach Park. Kennydale Beach Park is a 1.8-acre park located approximately 0.3 miles north of Coleman Point. Forty-nine of the 57 parcels where the lakeline system will be decommissioned have small docks permanently mounted on pilings. The shorelines of all of the properties are armored with either stone or concrete bulkheads. Construction Methods The decommissioned pipeline will be left in place to avoid excavation, disturbing sediment, and adversely affecting sensitive habitats in the project vicinity. Before decommissioning activities begin, the lakeline will be cleaned. Lakeline cleaning will consist of flushing the line with water to remove accumulated materials. The source of the flushing water will be the existing lake intake to the flush station. Water used for flushing the line will be conveyed via the existing system to the King County regional system and will not enter surface waters. Once the line is cleaned, the pipe is proposed to be filled with lake water to avoid needing to pump controlled density fill (CDF) into the pipeline and the potential for CDF to enter the water if there are leaks or breaks in the pipe. The removal of the 3 existing manholes will also occur, resulting in the removal of approximately 33 CY of material. Removal of the manholes will occur via barge stationed equipment (e.g., backhoe or similar) whereby the manhole will be excavated and lifted onto the barge for removal. Fill will be added to each excavated area (refer to the restoration and cleanup section). The flush station located at the south end of the Kennydale lakeline system (APN 0523059010) will be decommissioned. The intake pipe at the flush station will be left in place. The primary work will include removing the interior components and adjacent appurtenances of the flush station (the shelter, antenna, light, etc.). The above-grade SEPA Environmental checklist May 2025 Page 8 (WAC 197-11-960) electrical/controls shelter, electrical vault, antenna, and site lighting will be removed. Additional details are provided in the project drawings. The Lake Washington Lift Station No. 2 is located on-land on the northern end of the lakeline system (APN 3342700011). In addition to lakeline system flow, the lift station collects flow north of the station from an upland gravity system and will remain with minor upgrades to its Supervisory Control and Data Acquisition (SCADA) and electrical systems to allow for connection to the new permanent generator. A small retaining wall will be added to protect the new generator. The area of the transformer and generator may require a retaining wall or other slope stabilization method and appropriate screening as required by code. These minor upgrades will result in approximately 500 SF of new impervious surface area. Restoration and Cleanup Once decommissioning activities are completed, work areas will be restored to be similar to existing surrounding conditions. A description of in-water restoration is provided in Section A.3.a below. 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist. Upland of and within Lake Washington, between 3905 Lake Washington Blvd N, Renton WA, 98056 and the northern end of Gene Coulon Memorial Beach Park (1201 Lake Washington Blvd N, Renton WA, 98056) (refer to Project Drawings). The project falls within the following Section/Township/Ranges: • S32, T24N, R5E • S31, T24N, R5E • S6, T23N, R5E B. Environmental Elements 1. Earth Find help answering earth questions3 a. General description of the site: The project is located between 3905 Lake Washington Blvd N and the northern end of Gene Coulon Memorial Beach Park (1201 Lake Washington Blvd N) in Renton, Washington. Phase 1 is located upland within private residences between these 3 https://ecology.wa.gov/regulations-permits/sepa/environmental-review/sepa-guidance/sepa-checklist- guidance/sepa-checklist-section-b-environmental-elements/environmental-elements-earth SEPA Environmental checklist May 2025 Page 9 (WAC 197-11-960) addresses and in the roadway in front of the private residences. Phase 2 is located within Lake Washington approximately 50 feet from OHWM, and is described further in Question A.11. There is a small upland portion of the existing lakeline at the flush station (APN 0523059010), which will be decommissioned and removed. Circle or highlight one: Flat, rolling, hilly, steep slopes, mountainous, other: b. What is the steepest slope on the site (approximate percent slope)? Slopes range from 5-15% across most of the project area, with a small region of Alderwood gravelly sandy loam at the southmost end of the project area that ranges from 15-30% (Bush et al. 2024). The bathymetry of the lake is gradual in the project vicinity with water depths between 6 and 20 feet. c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, muck)? If you know the classification of agricultural soils, specify them, and note any agricultural land of long-term commercial significance and whether the proposal results in removing any of these soils. The sediment characteristics underlying the water along the vessel routes in the study area include sand, gravel, and cobble, along with various combinations of these sediment types. The upland soils generally include Alderwood gravelly sandy loam and Indianola loamy sand (USDA 2024). Five sample borings along the project site, which were advanced to depths of 15.5 to 25.9 feet below the ground surface, encountered glacial till with very dense silty sand, fine-grained sandy silt, sand with silt and gravel, clayey sand with gravel, and lean clay with sand (Shannon and Wilson 2024). d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. No, the project is a developed location with private residences and a public roadway. No evidence or documented history of unstable soils in the immediate vicinity. Refer to the Geotechnical Report for further information (Shannon and Wilson 2024). The sewer line has been in place since 1972 with no history of failure due to unstable soils. e. Describe the purpose, type, total area, and approximate quantities and total affected area of any filling, excavation, and grading proposed. Indicate source of fill. Excavation for Phase 1 will be to install the upland ILS to provide wastewater service to homes along the Kennydale lakeline system. The following values add 15% to account for potential changes during design. Installation of the ILS will include excavation of approximately 5,417 cubic yards (CY) for the force main; 2,458 CY for the discharge laterals; 674 CY for the grinder pumps; and 1,014 CY for electrical service. Excavation will include approximately 6,295 CY of asphalt; 1,176 CY of specialty pavement, concrete, or gravel; 657 CY of lawn; and 1,434 CY of landscaping. All surfaces will be replaced to existing conditions. Total temporary disturbed area will be 113,670 SF. Fill activities include placing grinder pumps, the force main, discharge laterals, and electrical service under the ground surface. Backfill quantities are expected to be very SEPA Environmental checklist May 2025 Page 10 (WAC 197-11-960) similar to fill quantities, though slightly lower to account for installed structures. Re- grading is anticipated in the public roadway when it is replaced following installation of the force main, which will improve stormwater drainage (refer to Project Drawings). Excavation and fill for Phase 2 will be to decommission the existing Kennydale lakeline system after the ILS are installed for each private residence. This is in-water work and is described in Section 3 below. f. Could erosion occur because of clearing, construction, or use? If so, generally describe. Yes, during construction temporary ground disturbance would be necessary and could result in erosion. Additionally, five parcels (3342104050, 3342104048, 3342104046, 3342104045, 3124059004) overlap with an area of high erosion risk in the southernmost part of the project area (Renton 2025). However, a Temporary Erosion and Sediment Control (TESC) Plan would be developed and followed during construction to avoid and minimize erosion and negative effects associated with erosion and sediment transport. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? There will be minimal changes to the amount of site covered with impervious surfaces after project construction. The only change is the addition of a generator and retaining walls at Lake Washington Lift Station No. 2, which will result in approximately 500 SF of new impervious surface area. h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any. The following BMPs will be used during construction to reduce or control erosion and sedimentation: • A TESC Plan and a Source Control Plan will be developed and implemented for all clearing, vegetation removal, grading, ditching, filling, soil compaction, or excavation. The BMPs in the plans will be used to control sediments from all vegetation removal or ground disturbing activities. • A Construction Stormwater Pollution Prevention Plan (CSWPPP) will be developed to protect local water quality during construction. • The contractor will designate at least one employee as the erosion and spill control (ESC) lead, also called a Certified Erosion and Sediment Control Lead (CESCL; BMP C160). The CESCL will be responsible for the installation and monitoring of erosion control measures and maintaining spill containment and control equipment. The CESCL will also be responsible for ensuring compliance with all erosion and sediment control requirements. • All exposed soils will be stabilized during the first available period, and no soils will remain without stabilization for more than two days from October 1 to April 30 or for more than seven days from May 1 to September 30. SEPA Environmental checklist May 2025 Page 11 (WAC 197-11-960) • Disturbed areas will be returned to existing or improved conditions (e.g., replanting or repaving) as soon as practical after construction is completed. • With a limited storm drainage system along the alignment, construction site dewatering discharge locations should be identified during the design process. Where catch basins are not close to construction, dewatering volumes may need to be stored, removed, and disposed of off-site. 2. Air Find help answering air questions4 a. What types of emissions to the air would result from the proposal during construction, operation, and maintenance when the project is completed? If any, generally describe and give approximate quantities if known. Phase 1 of the project, which would last approximately 18 months, would emit dust through the excavation of 9,562 CY and the filling of excavated areas. Some emissions will also be released from concrete and asphalt preparation, from the use of construction equipment, and from fuel storage. Phase 2 of the project, which will last approximately 6 weeks, would require a work barge and boat. Emissions from project construction would be limited to approximately 3 gasoline generators during daily operations plus outboard boat engines for site access and environmental monitoring during operations. Minimal emissions are expected from the maintenance and operation of the sanitary sewer system when the project is completed and include emissions from vehicle transport to conduct maintenance and repairs on the system. b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe. No off-site sources of emissions or odor have been identified that would affect the proposed project. c. Proposed measures to reduce or control emissions or other impacts to air, if any: Engines will be turned off when not in use. Regular street cleaning will occur where necessary to control mud and dust. Disturbed soils will be stabilized at the first available period and measures like wattle installation, plastic covering installation, seeding, and mulching will be used for temporary and permanent erosion protection. 4 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-Air SEPA Environmental checklist May 2025 Page 12 (WAC 197-11-960) 3. Water Find help answering water questions5 a. Surface: Find help answering surface water questions 6 1. Is there any surface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, lakes, ponds, wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. The project is situated in and directly upland of Lake Washington. May Creek, a small perennial stream draining approximately 9,000 acres, is located approximately 0.2 miles north of the northernmost project location. The stream is well outside of project activities and the project will have no effect on the stream. 2. Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. Yes. Phase 1 of the project consists of constructing a new land-based sewer system, using open-trench and trenchless (where possible) methods to install a force main, discharge laterals, electrical system, and ILS with grinder pumps. The ILS will be as close as 5 feet and up to 200 feet landward of the OHWM of Lake Washington. Phase 2 of the project includes decommissioning of the existing lakeline system located approximately 50 feet waterward of the OHWM, which will be left in place. Removal of manholes will occur via barge stationed equipment (e.g., backhoe or similar) whereby the manhole will be excavated and lifted onto the barge for removal. Other elements of the decommissioning include capping the flush station intake pipe in Lake Washington and removing the interior components and adjacent appurtenances located 33 feet landward of the OHWM. The above-grade electrical/controls shelter, electrical vault, antenna, and site lighting will be removed. Refer to the Project Drawings for details on this work. 3. Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. For in-water work, 33 CY of material will be excavated when the 3 existing manholes are removed. The area will be backfilled to 6 inches below original grade and then top dressed to original grade with spawning gravel mix (estimated as 11 CY of fill). An additional 2 CY of gravels will be placed in locations where the pipe is exposed, which is estimated at 2 locations. Note that the number of exposed locations is not 5 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-3-Water 6 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-3-Water/Environmental- elements-Surface-water SEPA Environmental checklist May 2025 Page 13 (WAC 197-11-960) known but is assumed to be a minimum of 2 locations. Finally, gravel will be placed at the flush station intake (~2 CY). It is estimated that restoration will include a total fill of 39 CY. 4. Will the proposal require surface water withdrawals or diversions? Give a general description, purpose, and approximate quantities if known. No surface water withdrawals or diversions would be necessary. 5. Does the proposal lie within a 100-year floodplain? If so, note location on the site plan. No, Lake Washington is not a 100-year floodplain. 6. Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No, during construction of Phase 1, discharge will be controlled through typical construction BMPs. Before decommissioning activities begin (Phase 2), the lakeline system will be cleaned. Lakeline cleaning will consist of flushing the line with water to remove accumulated materials. The source of the flushing water will be the existing lake intake to the flush station. Water used for flushing the line will be conveyed via the existing system to the King County regional wastewater system and will not enter surface waters. b. Ground: Find help answering ground water questions7 1. Will groundwater be withdrawn from a well for drinking water or other purposes? If so, give a general description of the well, proposed uses and approximate quantities withdrawn from the well. Will water be discharged to groundwater? Give a general description, purpose, and approximate quantities if known. No groundwater will be withdrawn from a well for drinking water or other purposes. 2. Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (domestic sewage; industrial, containing the following chemicals…; agricultural; etc.). Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. No waste material will be discharged into the ground from septic tanks or other sources. The purpose of the project is to provide grinder pump systems for private residences that will be connected to the King County regional wastewater system. 7 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-3-Water/Environmental- elements-Groundwater SEPA Environmental checklist May 2025 Page 14 (WAC 197-11-960) c. Water Runoff (including stormwater): 1. Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. BMPs will be employed to avoid stormwater runoff in Phase 1 of the project, including the use of temporary storage tanks, baker tanks, or a vacuum excavator truck to control sediment and flow rate. See item 3d below for more detail on proposed measures to reduce or control runoff water. 2. Could waste materials enter ground or surface waters? If so, generally describe. For Phase 1, waste materials will be monitored, contained, and prevented from entering surface and ground waters. When saw cutting and surfacing operations generate slurry and process water, the project will follow the design and installation specifications outlined in the 2024 Stormwater Management Manual for Western Washington, that include vacuuming slurry and cuttings during cutting and surfacing work, detaining slurry, and process water, and disposing of all waste materials appropriately so they don’t enter stormwater or watercourse systems. Phase 2 activities will not create waste materials that could enter ground or surface waters. 3. Does the proposal alter or otherwise affect drainage patterns in the vicinity of the site? If so, describe. Limited changes to drainage patterns are anticipated in the public roadway to improve stormwater drainage when the public road is replaced after installation of the force main. Refer to the Project Drawings for details on this work. d. Proposed measures to reduce or control surface, ground, and runoff water, and drainage pattern impacts, if any: During upland construction, temporary storage tanks, baker tanks, or a vacuum excavator truck will be used to control sediment and flow rate. Storage will be used when collecting sediment-contaminated stormwater that is not collected by inlet protection installed in catch basins or ends up collecting at low points around the project site. The contractor will discharge stormwater at a controlled rate to prevent erosion downstream of the project site once turbidity is controlled 4. Plants Find help answering plants questions a. Check the types of vegetation found on the site: ☒ deciduous tree: alder, maple, aspen, other ☒ evergreen tree: fir, cedar, pine, other ☒ shrubs ☒ grass SEPA Environmental checklist May 2025 Page 15 (WAC 197-11-960) ☐ pasture ☐ crop or grain ☐ orchards, vineyards, or other permanent crops. ☐ wet soil plants: cattail, buttercup, bullrush, skunk cabbage, other ☒ water plants: water lily, eelgrass, milfoil, other ☐ other types of vegetation b. What kind and amount of vegetation will be removed or altered? The vegetation removed will be landscaped vegetation that is part of the single family residences affected. There are a total of 4 significant trees proposed to be removed outside of critical areas or buffers but within the shoreline. Replacement of significant trees are based on Renton and King County codes (RMC 4-4-130H.1.b, RMC 9-13-8B, and KCC 16.82.156E.2.a,b). A Vegetation Management Plan provides details on the location and type of restoration for each area that is disturbed (Confluence and Tree Solutions 2025). Due to limited available space, the appropriate number of replacement trees will be located at an offsite location. c. List threatened and endangered species known to be on or near the site. No listed plants are known to be on or near the site. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any. Vegetation removed during construction activities will be replaced at a 1:1 ratio using native species or replacing landscaped species. Natural vegetation will be preserved where practicable to reduce erosion, including on steep slopes, near perennial and intermittent watercourses or swales, and on building sites in wooded areas. Temporary and permanent seeding and planting will be used to stabilize soils and reduce erosion. e. List all noxious weeds and invasive species known to be on or near the site. Common non-native species in Lake Washington include milfoil, hydrilla, elodea and water hyacinth. In-water excavations are anticipated to occur outside of vegetated beds, but some non-native aquatic vegetation may be present at some sites. 5. Animals Find help answering animal questions8 a. List any birds and other animals that have been observed on or near the site or are known to be on or near the site. Examples include: • Birds: hawk, heron, eagle, songbirds, other 8 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-5-Animals SEPA Environmental checklist May 2025 Page 16 (WAC 197-11-960) • Mammals: deer, bear, elk, beaver, other • Fish: bass, salmon, trout, herring, shellfish, other Many bird species have been observed on and near the site, including the following species: 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) (iNaturalist 2024). Birds will use the project site for foraging and migration. An osprey nest was identified approximately 1,000 feet north of the mouth of May Creek, along N 42nd Place, and bald eagle nests on the south end of Mercer Island. A bald eagle was observed in a mature conifer at 3827 Mountain View Ave N and a land owner at 3009 Mountain View Ave N observes regular use of the area by a foraging eagle. Mammals observed on and near the site include mule deer (Odocoileus hemionus), eastern cottontails (Sylvilagus floridanus), North American river otters (Lontra canadensis), and eastern grey squirrels (Sciurus carolinensis) (iNaturalist 2024). Mammals will use the project site for foraging either in riparian areas or in Lake Washington and May Creek. Fish observed on and near the site include endangered fish species (see response to 5b below) and other fish species, including common sunfishes (Genus Lepomis), freshwater sculpins (Genus Cottus), yellow perch (Perca flavescens), and threespine stickleback (Gasterosteus aculeatus) (WDFW 2025). Fish will use the area for foraging and migration. b. List any threatened and endangered species known to be on or near the site. Sockeye salmon ( Oncorhynchus nerka), steelhead trout (O. mykiss), coho salmon (O. kisutch), cutthroat trout (O. clarki), bull trout (Salvelinus confluentus), and Chinook salmon (O. tshawytscha) are present near the site in May Creek and Lake Washington (WDFW 2025b, 2025a). c. Is the site part of a migration route? If so, explain. Yes. Multiple species migrate through Lake Washington. Migratory birds may use the area as a stopover site, and migratory fish moving to Puget Sound, Lake Washington, or the Lake Washington tributaries may move past the site. d. Proposed measures to preserve or enhance wildlife, if any. Isolation of the in-water work area using a turbidity curtain will remove and exclude fish from the vicinity of the project, while also containing project-related turbidity. Impacts on wildlife will be reduced by decreasing construction noise through BMPs like use of adequate mufflers, intake silencers, and engine enclosures, turning off equipment during prolonged periods of non-use, and maintaining equipment properly. e. List any invasive animal species known to be on or near the site. New Zealand mud snail (Potamopyrgus antipodarum), oriental weatherfish (Misgurnus anguillicaudatus), walleye (Sander vitreus), and northern pike (Esox lucius) are all known SEPA Environmental checklist May 2025 Page 17 (WAC 197-11-960) to occur in Lake Washington and/or its tributaries (WDFW 2025c). Specific surveys of the project sites have not been conducted. 6. Energy and natural resources Find help answering energy and natural resource questions9 a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. Gasoline would be used for operation of engines to power generators, pumps, and/or outboard motors during decommissioning activities. Other equipment for upland work will also use gasoline, including mini-excavator, vacuum excavator truck, high-pressure water knife, vibratory hammer or other compaction equipment, and dump truck. Equipment used for maintenance will include vacuum excavator trucks, gantry crane mounted utilities and trucks, and utility vehicles. b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. No, the project would not affect the potential use of solar energy by adjacent properties. c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any. None. 7. Environmental health Health Find help with answering environmental health questions10 a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur because of this proposal? If so, describe. Concrete work, saw cutting, and surfacing can generate process water and slurry that contain fine particles and high pH, both of which can violate water quality standards in the receiving water. The improper use of construction equipment can result in local contamination due to fuel and oil spills. BMPs will be in place to prevent contamination and ensure that process water and slurry will not enter waterways. 1. Describe any known or possible contamination at the site from present or past uses. Three residential addresses within or near the project area have experienced contamination from past uses. 3401 Burnett Ave N and 3403 Burnett Ave N had documented presence of non-halogenated organics/petroleum-diesel and have 9 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-6-Energy-natural-resou 10 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-7-Environmental-health SEPA Environmental checklist May 2025 Page 18 (WAC 197-11-960) completed cleanup according to the Washington State Department of Ecology (Ecology). Ecology (2025) lists 2929 Mountain View Ave N as suspected of having presence of various metal contaminants, non-halogenated organics, and reactive waste (CSID 2790). This address is identified as “still awaiting cleanup.” Note that the Ecology database lists this as 2909 Mountain View Ave N (Marshall Residence) but the location matches the address for 2929 Mountain View Ave N. 2. Describe existing hazardous chemicals/conditions that might affect project development and design. This includes underground hazardous liquid and gas transmission pipelines located within the project area and in the vicinity. None known. 3. Describe any toxic or hazardous chemicals that might be stored, used, or produced during the project's development or construction, or at any time during the operating life of the project. Gasoline may be used on support boats and/or barges and fuel will be used for equipment and may be stored in chemical/petroleum storage containers. 4. Describe special emergency services that might be required. Should an accident occur during construction, the injured individual(s) would be transported by vehicle or boat to an appropriate dock for offloading and transported to a hospital for treatment. 5. Proposed measures to reduce or control environmental health hazards, if any. Best management practices related to the handling and storage of any potentially harmful materials will be implemented to avoid and minimize any potential hazards. These include the following: • Taking precautions during concrete handling, saw cutting, and surfacing. • Storing fuels and other potential contaminants in secured containment areas. • Containing equipment, materials, and wash water associated with construction. • Conducting regular inspections, maintenance, and repairs of fuel hoses, hydraulically operated equipment, lubrication equipment, and chemical/petroleum storage containers. • Regularly maintaining spill containment and clean up material at construction sites. • Establishing a communication protocol for handling spills (e.g., ESC lead). • Refueling construction equipment and vehicles away from surface waters whenever practicable. SEPA Environmental checklist May 2025 Page 19 (WAC 197-11-960) b. Noise 1. What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? Ambient noise conditions are from adjacent residences, Interstate 405, and recreational boats operating on Lake Washington. Noise levels are generally higher during the day and lower at night. 2. What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site)? There will be short-term noise associated with both phases of this project. Phase 1 of the project will generate noise from equipment and activity associated with open- trench excavation to install sanitary sewer lines and ILS systems and potentially from trenchless methods if used. Phase 2 of the project will generate noise from transit to and from the project sites from outboard engines, operation of motors for pipeline cleaning, and removal of 3 existing manholes along the lakeline. Noise levels from sewer line cleaning and decommissioning and operation of the work vessel, are not expected to exceed ambient underwater noise levels. Ambient noise includes frequent recreational boat traffic on Lake Washington. An increase in terrestrial noise associated with the proposed project is expected to attenuate to an ambient noise level within approximately 223 feet when the pumps are running. Noise will be generated during the day when construction is actively underway. No long-term changes to noise levels will occur following the completion of the project. 3. Proposed measures to reduce or control noise impacts, if any: Project activities will occur during daylight hours and will adhere to the construction standards identified under RMC 4-4-030(C)(3). Construction activities for single family residential areas shall be restricted to the hours between seven o’clock (7:00) a.m. and ten o’clock (10:00) p.m., Monday through Friday. Work on Saturdays and Sundays shall be restricted to the hours between nine o’clock (9:00) a.m. and ten o’clock (10:00) p.m. Other BMPs for noise will be based on contractor means and methods. 8. Land and shoreline use Find help answering land and shoreline use questions 11 a. What is the current use of the site and adjacent properties? Will the proposal affect current land uses on nearby or adjacent properties? If so, describe. Adjacent properties are primarily single family residential properties. Two parks are located in the project vicinity – Kennydale Beach Park is part of the project and Gene Coulon Park is approximately 0.5 miles to the south. The existing lakeline system is 11 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-8-Land-shoreline-use SEPA Environmental checklist May 2025 Page 20 (WAC 197-11-960) located approximately 10 to 50 feet from the shoreline of Lake Washington. Lake Washington is used for recreational purposes by various types of watercraft. The project will not affect current land uses on nearby or adjacent properties. b. Has the project site been used as working farmlands or working forest lands? If so, describe. How much agricultural or forest land of long-term commercial significance will be converted to other uses because of the proposal, if any? If resource lands have not been designated, how many acres in farmland or forest land tax status will be converted to nonfarm or nonforest use? The site has not been used as working farmlands or working forest lands. 1. Will the proposal affect or be affected by surrounding working farm or forest land normal business operations, such as oversize equipment access, the application of pesticides, tilling, and harvesting? If so, how? No working farm or forest land would affect the construction or operations of the project. c. Describe any structures on the site. d. Structures on the project site are primarily single family residences and auxiliary structures (e.g., sheds, bulkheads, docks, boat lifts). Forty-nine of the 58 parcels where the lakeline system would be decommissioned have small docks permanently mounted on pilings. The shorelines of all properties are armored with either stone or concrete bulkheads. Several residences also have retaining walls, fences, or other types of structures. There are 3 manholes along the existing lakeline system. The flush station located at the south end of the Kennydale lakeline system (APN 0523059010) includes a shelter, antenna, light, and other appurtenances. There is also an above-grade electrical/controls shelter, electrical vault, antenna, and site lighting. Finally, the Lake Washington Lift Station No. 2 is located on-land on the northern end of the lakeline system (APN 3342700011). Lift Station No. 2 includes a shed that includes the power supply and auxiliary equipment. e. Will any structures be demolished? If so, what? The 3 existing manholes will be removed. Work at the flush station will include removing the interior components and adjacent appurtenances (shelter, antenna, light, etc.). The above-grade electrical/controls shelter, electrical vault, antenna, and site lighting will be removed. There are portions of retaining walls that will be temporarily removed and replaced during installation of the ILS. Refer to the Project Drawings for details on this work. f. What is the current zoning classification of the site? Residential-8, Residential-6, and Aquatic g. What is the current comprehensive plan designation of the site? Residential Medium Density and Residential High Density SEPA Environmental checklist May 2025 Page 21 (WAC 197-11-960) h. If applicable, what is the current shoreline master program designation of the site? Single Family Residential, Aquatic, and Urban Conservancy i. Has any part of the site been classified as a critical area by the city or county? If so, specify. Yes. Aquatic sites are designated critical areas. j. Approximately how many people would reside or work in the completed project? None. k. Approximately how many people would the completed project displace? None. l. Proposed measures to avoid or reduce displacement impacts, if any. Not Applicable. m. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any. This project replaces a failing sanitary sewer system and doesn’t impact current or projected land use. n. Proposed measures to reduce or control impacts to agricultural and forest lands of long-term commercial significance, if any: None. The proposed project will not affect agricultural or forest lands of long-term commercial significance. 9. Housing Find help answering housing questions12 a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. None. b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low-income housing. None. c. Proposed measures to reduce or control housing impacts, if any: None. 12 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-9-Housing SEPA Environmental checklist May 2025 Page 22 (WAC 197-11-960) 10. Aesthetics Find help answering aesthetics questions13 a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? No fence, hedge, or retaining wall will exceed 72 inches in height for the project. b. What views in the immediate vicinity would be altered or obstructed? None. c. Proposed measures to reduce or control aesthetic impacts, if any: None proposed. 11. Light and glare Find help answering light and glare questions14 a. What type of light or glare will the proposal produce? What time of day would it mainly occur? The project will occur during daylight hours and therefore is not expected to contribute to lighting or glare. Flashlights or similar may be used to illuminate work surfaces under water. b. Could light or glare from the finished project be a safety hazard or interfere with views? No. c. What existing off-site sources of light or glare may affect your proposal? Not applicable. d. Proposed measures to reduce or control light and glare impacts, if any: None, not applicable. 12. Recreation Find help answering recreation questions a. What designated and informal recreational opportunities are in the immediate vicinity? Gene Coulon Memorial Beach Park provides numerous upland recreation activities in addition to boat launches and a summer swimming area. Kennydale Beach Park includes a swim area and recreation and picnic areas. 13 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-10-Aesthetics 14 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-11-Light-glare SEPA Environmental checklist May 2025 Page 23 (WAC 197-11-960) Informal recreational opportunities in the area include park amenities, boating, kayaking, fishing, and wildlife viewing. People also walk, bike, run, and generally recreate on the Eastrail multi-use trail. b. Would the proposed project displace any existing recreational uses? If so, describe. No. All impacts of the project will be temporary. Project work may limit boating, fishing, and use of the Eastrail trail in the immediate vicinity of construction activities. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: None, not applicable. 13. Historic and cultural preservation Find help answering historic and cultural preservation questions15 a. Are there any buildings, structures, or sites, located on or near the site that are over 45 years old listed in or eligible for listing in national, state, or local preservation registers? If so, specifically describe. No historic structures or sites are present in the project area. b. Are there any landmarks, features, or other evidence of Indian or historic use or occupation? This may include human burials or old cemeteries. Are there any material evidence, artifacts, or areas of cultural importance on or near the site? Please list any professional studies conducted at the site to identify such resources. No, there is no evidence of Indian or historic use or occupation on the project site. In July 2024 Cheyenne Thompson of Carollo Engineers contacted Kelly R. Bush of Equinox Research and Consulting International Inc. (ERCI) to carry out an archaeological survey and monitoring for the project. Following background research, ERCI provided geotechnical monitoring on August 28 and 29, 2024, to look for material traces of past human activity and found no evidence of Protected Cultural Resources or Historic Properties (Bush et al. 2024). c. Describe the methods used to assess the potential impacts to cultural and historic resources on or near the project site. Examples include consultation with tribes and the department of archeology and historic preservation, archaeological surveys, historic maps, GIS data, etc. Archaeological surveys were conducted by Equinox Research and Consulting International Inc. (ERCI) to assess the potential impacts to the cultural and historic resources on the project site (Bush et al. 2024). ERCI researchers first conducted background research, including reviewing archival information from the department of archeology and historic preservation, published information on traditional Native American land use around the project area, County Assessor’s records, General Land Office maps, and other archaeological reports. ERCI then conducted fieldwork to 15 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-13-Historic-cultural-p SEPA Environmental checklist May 2025 Page 24 (WAC 197-11-960) monitor the geotechnical borings on the project site, recording sediments seen in the borehole samples and whether cultural resources were present (Bush et al. 2024). d. Proposed measures to avoid, minimize, or compensate for loss, changes to, and disturbance to resources. Please include plans for the above and any permits that may be required. For Phase 1, trenchless methods will be used when feasible and will result in fewer impacts compared to open-trench methods. Temporarily affected areas will be restored in-kind to existing conditions. Vegetation will be replaced at a 1:1 ratio using native species or replacing landscaped species. In some sections, the entire road base and subbase will be reconstructed (rather than trench repair or overlays), and the asphalt surface will be reprofiled to better manage surface water runoff. Asphalt overlay may be required in other parts of the roadway in addition to a trench patch, depending on the location of the trench patch and the jurisdiction of the roadway. For Phase 2, the decommissioned pipeline will be left in place to avoid excavation, disturbing sediment, and adversely affecting sensitive habitats within the project vicinity. For areas where manholes are removed, the area will be backfilled to 6 inches below original grade and then top dressed to original grade with spawning gravel mix. Additional gravels will be placed in locations where the pipe is exposed, which is estimated at 2 locations. Note that the number of exposed locations is not known but is assumed to be a minimum of 2 locations. Finally, gravel will be placed at the flush station intake. Gravel placement will provide habitat for juvenile salmonids as well as support spawning for sockeye salmon. Existing side sewer laterals of the lakeline system will be capped above the OHWM to avoid the need for in-water excavation. Additionally, the flush station located at the south end of the lakeline will be decommissioned and the intake pipe connected to the flush station would be left in place. 14. Transportation Find help with answering transportation questions 16 a. Identify public streets and highways serving the site or affected geographic area and describe proposed access to the existing street system. Show on site plans, if any. Phase 1 of the project will be along Mountain View Avenue North and an unnamed roadway that parallels Lake Washington Boulevard North. Vehicular access to Mountain View Avenue North is just west of the intersection of Lake Washington Boulevard North and North 33rd Street. Vehicular access to the roadway adjacent to Lake Washington Boulevard North is just west at the intersection of Lake Washington Boulevard North and North 37th Street. Phase 2 of the project is aquatic and will be accessed by boats launched from nearby boat launches. 16 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-B-Environmental-elements/Environmental-elements-14-Transportation SEPA Environmental checklist May 2025 Page 25 (WAC 197-11-960) b. Is the site or affected geographic area currently served by public transit? If so, generally describe. If not, what is the approximate distance to the nearest transit stop? The site is not served by public transit. The closest nearest transit stop is the I-405 / 30th Street Kennydale Freeway station, which is approximately 0.45 miles away from the project site. c. Will the proposal require any new or improvements to existing roads, streets, pedestrian, bicycle, or state transportation facilities, not including driveways? If so, generally describe (indicate whether public or private). This project will involve reconstructing and patching or replacing existing public roadways. In some sections, the entire road base and subbase will be reconstructed (rather than trench repair or overlays), and the asphalt surface will be reprofiled to better manage surface water runoff. Asphalt overlay may be required in other parts of the roadway in addition to a trench patch, depending on the location of the trench patch and the jurisdiction of the roadway. d. Will the project or proposal use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. For Phase 2, small work boats and/or barges will be used to access the site. e. How many vehicular trips per day would be generated by the completed project or proposal? If known, indicate when peak volumes would occur and what percentage of the volume would be trucks (such as commercial and nonpassenger vehicles). What data or transportation models were used to make these estimates? No additional vehicle trips will be generated by the completed project compared to existing conditions. While the generator site will have new maintenance activities, this will be replaced by maintenance needs at the flush station. f. Will the proposal interfere with, affect, or be affected by the movement of agricultural and forest products on roads or streets in the area? If so, generally describe. No. g. Proposed measures to reduce or control transportation impacts, if any: None. 15. Public services Find help answering public service questions17 a. Would the project result in an increased need for public services (for example: fire protection, police protection, public transit, health care, schools, other)? If so, generally describe. No. 17 https://ecology.wa.gov/regulations-permits/sepa/environmental-review/sepa-guidance/sepa-checklist- guidance/sepa-checklist-section-b-environmental-elements/environmental-elements-15-public-services SEPA Environmental checklist May 2025 Page 26 (WAC 197-11-960) b. Proposed measures to reduce or control direct impacts on public services, if any. None proposed. 16. Utilities Find help answering utilities questions18 a. Circle utilities currently available at the site: electricity, natural gas, water, refuse service, telephone, sanitary sewer, septic system, other: b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. This project involves the installation of a new sanitary sewer service to replace the sanitary sewer service provided by the Kennydale lakeline system. The City will own and maintain the entire ILS sewer system, including the individual grinder pumps. 18 https://ecology.wa.gov/regulations-permits/sepa/environmental-review/sepa-guidance/sepa-checklist- guidance/sepa-checklist-section-b-environmental-elements/environmental-elements-16-utilities SEPA Environmental checklist May 2025 Page 27 (WAC 197-11-960) C. Signature Find help about who should sign 19 The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. X Type name of signee: Position and agency/organization: Date submitted: D. References Bush, K., M. Henley, and L. Koch-Michael. 2024. Archaeological monitoring report: Kennydale lakeline sewer system improvement project, Renton, King County, Washington. Prepared for Carollo Engineers, Seattle, Washington. Prepared by Equinox Research and Consulting International Inc., Mount Vernon, Washington. Carollo (Carollo Engineers). 2025. City of Renton: Kennydale lakeline sewer system improvement, CAG 23-403. Prepared by Carollo, Seattle, Washington. Prepared for City of Renton, Renton, Washington. Confluence (Confluence Environmental Company). 2017. Kennydale lakeline sewer system: Environmental conditions report. Prepared for Carollo Engineers, Seattle, Washington. Prepared by Confluence Environmental Company, Seattle, Washington. Confluence. 2025a. Kennydale lakeline sewer system replacement project: Project narrative and code consistency analysis. Prepared for Carollo Engineers, Seattle, Washington. Prepared by Confluence Environmental Company, Seattle, Washington. Confluence. 2025b. Kennydale lakeline sewer system replacement project: Lake study. Prepared for Carollo Engineers, Seattle, Washington. Prepared by Confluence Environmental Company, Seattle, Washington. Confluence and Tree Solutions (Tree Solutions Inc.). 2025. Kennydale lakeline sewer system replacement project: Vegetation management plan. Prepared for Carollo Engineers, Seattle, 19 https://ecology.wa.gov/Regulations-Permits/SEPA/Environmental-review/SEPA-guidance/SEPA-checklist- guidance/SEPA-Checklist-Section-C-Signature SEPA Environmental checklist May 2025 Page 28 (WAC 197-11-960) Washington. Prepared by Confluence Environmental Company and Tree Solutions Inc., Seattle, Washington. Ecology (Washington State Department of Ecology). 2025. What’s in my neighborhood: Toxics cleanup | Online Data. Ecology, Olympia, WA. Available at: https://apps.ecology.wa.gov/neighborhood/?lat=47.517805&lon=- 122.208276&zoom=18&radius=false (assessed on May 2, 2025). iNaturalist. 2024. Observations [online database with search boundary along Kennydale Lakeline]. Available at: https://www.inaturalist.org/observations?nelat=47.5299395713488&nelng=- 122.20236972544616&subview=table&swlat=47.512202864101184&swlng=- 122.21369937632507&view=species&iconic_taxa=Aves (Accessed on December 10, 2024). Renton (City of Renton). 2025. COR Maps | Online Data. City of Renton, Renton, WA. Available at: https://maps.rentonwa.gov/Html5viewer/Index.html?viewer=cormaps (accessed on March 12, 2025). Shannon & Wilson Inc. 2024. Geotechnical engineering report: Kennydale lakeline sewer improvements, Renton, Washington. Prepared for Carollo Engineers, Seattle, Washington. Prepared by Shannon & Wilson Inc., Seattle, Washington. USDA (U.S. Department of Agriculture). 2024. Web Soil Survey [online database]. USDA, Renton, WA. Available at: https://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx (Accessed on December 10, 2024). WDFW (Washington Department of Fish and Wildlife). 2024. Priority Habitats and Species (PHS) on the Web [online database]. WDFW, Olympia, WA. Available at: https://geodataservices.wdfw.wa.gov/hp/phs-test/ (Accessed on December 10, 2024).