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HomeMy WebLinkAboutERC_Williams_ADU_Garage_FINALDEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT Project Location Map ERC_WI~1 ENVIRONMENTAL REVIEW COMMITTEE REPORT ERC Meeting Date: March 17, 2025 Project File Number: PR25-000012 Project Name: Williams ADU/Garage Land Use File Number: LUA25-000025, ECF, SSDP, MOD Project Manager: Jill Ding, Senior Planner Owner/Applicant: Jamie Williams, 13411 SE 151st St, Renton, WA, 98058 Contact: Patty Thuman, 13411 SE 151st St, Renton, WA 98058 Project Location: 13411 SE 151st St, Renton, WA 98058 (APN 2223059112) Project Summary: The applicant is requesting a Shoreline Substantial Development Permit, Environmental (SEPA) Review, and a height modification for the construction of a two (2) story 1,012 square foot detached accessory dwelling unit (ADU). The project site is a 37,744 square foot lot within the Residential-4 (R-4) zone that is currently developed with a single-family home and associated accessory structures. The site is currently accessed via a residential driveway off of SE 151st St. A height modification is requested to allow the proposed ADU to exceed the height of the existing single family residence. According to the City of Renton Maps (COR Maps), the project site is mapped with a Wellhead Protection Area Zone (Zone 2, Maplewood Wellfield), Special Flood Hazard Areas (100 year flood, FEMA Zone-AE), Moderate to Severe Channel Migration Zone Hazards, Regulated Shoreline High Intensity Environmental Designation, Regulated Shoreline: CR-C Cedar River Reaches Jurisdiction, High Seismic Hazards, Regulated Slopes, and High Erosion Hazards. Exist. Bldg. Area SF: 1,470 sq. ft. Proposed New Bldg. Area (footprint): Proposed New Bldg. Area (gross): 1,012 sq. ft. 2,024 sq. ft. Site Area: 37,744 sq. ft. (0.87 acres) Total Building Area GSF: 3,494 sq. ft. STAFF RECOMMENDATION: Staff Recommends that the Environmental Review Committee issue a Determination of Non-Significance - Mitigated (DNS-M). Docusign Envelope ID: 22A8539B-6B4F-45E9-B44D-17C2E5317108 City of Renton Department of Community & Economic Development Williams ADU/Garage Staff Report to the Environmental Review Committee LUA25-000025, ECF, SSDP, MOD Report of March 17, 2025 Page 2 of 4 ERC_WI~1 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 Discoveries Plan prepared by a qualified professional with the building permit for review and approval by the Current Planning Project Manager prior to permit issuance. C. Exhibits Exhibit 1: Environmental Review Committee (ERC) Report Exhibit 2: Site Plan Exhibit 3: Accessory Dwelling Unit (ADU) Building Plan Set Exhibit 4: Channel Migration Study, prepared by DCG Watershed, dated October 18, 2023 Exhibit 5: Wetland and Stream Assessment, prepared by J. S. Jones and Associates, Inc., dated November 20, 2021 Exhibit 6: Duwamish Tribe Comment Letter, dated January 30, 2025 Exhibit 7: City Response to Duwamish Comments, dated January 30, 2025 Exhibit 8: SEPA Environmental Checklist, prepared on December 26, 2024 Exhibit 9: 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. Water Impacts: The applicant submitted a Channel Migration Study, prepared by DCG Watershed, dated October 18, 2023 (Exhibit 4) and a Wetland and Stream Assessment, prepared by J. S. Jones and Associates, Inc., dated November 20, 2021 (Exhibit 5) with the project application materials. The project site is located along the Cedar River, which is a Shoreline of the State. The site is located within Reach C of the Cedar River, Special Flood Hazard Areas (100-year flood, FEMA Zone-AE), Moderate to Severe Channel Migration Zone Hazards, and is within the Shoreline High Intensity Designation. The proposed work would occur within the designated moderate channel migration zone. The moderate hazard area is located between the outer boundary of severe hazard and the maximum probable limits of future migration. No work is proposed within the severe channel migration zone. Work proposed within the 100-year flood plain would be limited to the installation of posts for an upper level deck. Docusign Envelope ID: 22A8539B-6B4F-45E9-B44D-17C2E5317108 City of Renton Department of Community & Economic Development Williams ADU/Garage Staff Report to the Environmental Review Committee LUA25-000025, ECF, SSDP, MOD Report of March 17, 2025 Page 3 of 4 ERC_WI~1 The Channel Migration Study concluded that the proposed ADU location would not be in an area subject to surface erosion or channel migration following major floods. The new construction proposed within this area would be unlikely to require new shoreline stabilization or other structural flood hazard reduction measures. The Wetland and Stream Assessment concluded that there were no wetlands present on the subject property. The Cedar River is classified as a Shoreline of the State and would be subject to the City’s adopted Shoreline Master Program and would not be subject to the City’s Critical Areas Regulations. The subject property has a lot depth of approximately 345 feet. According to the Shoreline Master Program, residential lots with a lot depth greater than 170 feet would be required to provide a 50-foot vegetation conservation buffer and a 15-foot building setback. The proposed ADU would be constructed approximately 180 feet from the ordinary high water mark (OHWM) of the Cedar River, which would exceed the 65-foot combined vegetation conservation buffer and building setback required. It is anticipated that the City’s currently adopted erosion control, construction, and drainage regulations would adequately mitigate for any impacts that could result from the proposed construction of the ADU; therefore, no further mitigation is recommended. Mitigation Measures: No further mitigation recommended. Nexus: Not Applicable. 2. Historic and Cultural Preservation Impacts: Staff received comments from the Duwamish Tribe (Exhibit 6), requesting that an Inadvertent Discovery Plan be followed in the case that archeological deposits are discovered during construction activities. To ensure that any archeological deposits are managed appropriately, staff recommends as a SEPA mitigation measure that the applicant submit an Inadvertent Discoveries Plan prepared by a qualified professional with the building permit for review and approval by the Current Planning Project Manager prior to permit issuance. Mitigation Measures: The applicant shall submit an Inadvertent Discoveries Plan prepared by a qualified professional with the building permit for review and approval by the Current Planning Project Manager prior to permit issuance. Nexus: State Environmental Policy Act (SEPA) Regulations; City of Renton Comprehensive Plan Goals and Policy, L-AA, L-44, and LU-45; RCW 27.53 Archeological Sites and Resources; and RCW 27.44 Indian Graves and Records; and Duwamish Tribe Comment Letter, dated January 30, 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” (Exhibit 9). ✓ 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 March 31, 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 Docusign Envelope ID: 22A8539B-6B4F-45E9-B44D-17C2E5317108 City of Renton Department of Community & Economic Development Williams ADU/Garage Staff Report to the Environmental Review Committee LUA25-000025, ECF, SSDP, MOD Report of March 17, 2025 Page 4 of 4 ERC_WI~1 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. Docusign Envelope ID: 22A8539B-6B4F-45E9-B44D-17C2E5317108 ERC_WI~1 CITY OF RENTON DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT STAFF REPORT TO THE ENVIRONMENTAL REVIEW COMMITTEE EXHIBITS Project Name: Williams ADU/Garage Land Use File Number: LUA25-000025, ECF, SSDP, MOD Date of Meeting March 17, 2025 Staff Contact Jill Ding Senior Planner Project Contact/Applicant Patty Thuman 13411 SE 151st St, Renton, WA 98058 Project Location 13411 SE 151st St, Renton, WA 98058 (APN 2223059112) The following exhibits are included with the ERC Report: Exhibit 1: Environmental Review Committee (ERC) Report Exhibit 2: Site Plan Exhibit 3: Accessory Dwelling Unit (ADU) Building Plan Set Exhibit 4: Channel Migration Study, prepared by DCG Watershed, dated October 18, 2023 Exhibit 5: Wetland and Stream Assessment, prepared by J. S. Jones and Associates, Inc., dated November 20, 2021 Exhibit 6: Duwamish Tribe Comment Letter, dated January 30, 2025 Exhibit 7: City Response to Duwamish Comments, dated January 30, 2025 Exhibit 8: SEPA Environmental Checklist, prepared on December 26, 2024 Exhibit 9: Advisory Notes Docusign Envelope ID: 22A8539B-6B4F-45E9-B44D-17C2E5317108