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HomeMy WebLinkAboutPN_project_narrative_20180913_v1_.pdfMemo To: Jill Ding, Senior Planner From: Kristi Rettmann City of Renton, Community and Economic Development 1055 S Grady Way, 6th Floor Renton, WA 98057 Stantec 11130 NE 33rd Place Suite 200 Bellevue WA 98004 File: 2002003611 Date: May 18, 2018 Reference: Project Narrative - #5 on the Submittal Requirements for Environmental Review (SEPA) for the Thunder Hills Sanitary Sewer Replacement Project • Project name, size, and location of site: Thunder Hills Sanitary Sewer Replacement Project. The project size is approximately 95,121 square feet (sf), which includes clear and grading easements for the sewer replacement and maintenance access path improvements. • Land use permits required for proposed project: A Land Use Permit Master Application is required as part of the SEPA submittal requirements list. • Zoning designation of the site and adjacent properties: The ravine where the project site resides runs through several tax parcels, the majority of which are zoned RM-F (residential multi-family), with some vacant RM-F land at the corner of South 18th Street and Grant Avenue South. The zoning of the small portion of the northern end of the site is R-8 (residential, 8 dwelling units per acre) as well as vacant. • Current use of the site and any existing improvements: The actual site is located down within a ravine. Currently the site is utilized as a sewer main access road/trail and contains Thunder Hills Creek. There are single-family (across the street on Eagle Ridge Road to the southwest of the project site) and multi-family residences (along the ravine where the project site is located), as well as open space/recreation areas surrounding the project alignment. The project area is crossed by Puget Sound Energy (PSE) high voltage electrical lines and an Olympic petroleum pipeline. The existing maintenance access road is also currently utilized by local pedestrians as a walking trail. Existing improvements include bank stabilization measures (rock gabions, placing rip rap in the stream, placing rip rap along the stream bank) implemented by the City to alleviate slumped hillside issues due to erosion impacts. • Special site features (i.e., wetlands, water bodies, steep slopes): Thunder Hills Creek, seven small tributaries to the creek, and six wetlands occur in the immediate vicinity of the project site. For the project, Thunder Hills Creek was designated as Stream A, the remaining tributaries were designated as Streams B-H, and the six wetlands on site were designated Wetlands A-F (as noted in the Stream and Wetland Delineation Report; The Watershed Company, 2015). Thunder Hills Creek is non-fish bearing, perennial stream that flows north, north-west through the ravine formed by the creek. • Statement addressing soil type and drainage conditions: The Natural Resources Conservation Services (NRCS) maps for King County indicate that the ravine and adjacent side slopes are underlain by Alderwood and Kitsap soils (very steep), Alderwood gravelly sandy loam (8% to 30% slopes) and Beausite gravelly sandy loam (15% to 30% slopes). There are no agricultural soils on the site. Soils within the north portion of the site consist of silty-sands and sandy-silts derived from weathering of the underlying sandstone and siltstone. Toward the south end of the site, soils are silty-sand with gravel, consistent with glacial till. Currently the drainage conditions of the site include percolation back into the soil and down into the creek. • Proposed use of the property and scope of the proposed development: The parcels that contain the sanitary sewer and maintenance access path will only be used to replace the existing sewer and upgrade the maintenance access path. • For plats, indicate the proposed number, net density, and range of sizes (net lot area) of the new lots: Not applicable, no new lots are proposed. • Access: The main access is a gated site entrance at Grant Ave S and S 18th Street, and there is an entrance at the cleared PSE easement access along S 18th Street. May 18, 2018 Jill Ding, Senior Planner Page 2 of 2 v:\2002\active\2002003611\permit\sepa\draft submittal\sepa_files_w_elec_file_standards\pn_project_narrative_20180913_v1_.docx • Proposed off-site improvements (i.e., installation of sidewalks, fire hydrants, sewer main, etc.): Not applicable, no off-site improvements are proposed. • Total estimated construction cost and estimated fair market value of the proposed project: To be determined. • Estimated quantities and type of materials involved if any fill or excavation is proposed: o Proposed new asphalt = approximately 5,439 sf o Proposed new gravel = approximately 34,161 sf o Buffer mitigation through vegetation re-planting for temporary and permanent impacts to wetland and stream buffers = approximately 42,945 sf • Number, type and size of any trees to be removed: 40 trees (see the Existing Site plans and Critical Areas Report), that are located directly in grading or maintenance access path areas are proposed to be removed. Tree types include alder, cedar, maple and cottonwood. Tree sizes range from 10” maple up to 44” cottonwood, with the majority of the trees falling within the 14” to 20” range. • Explanation of any land to be dedicated to the City: Not applicable, no land is to be dedicated to the City. • Any proposed job shacks, sales trailers, and/or model homes: A temporary field office (job shack) might be needed at this site for only the duration of the project construction. Location of the field office will be determined when the construction company is selected. • Any proposed modifications being requested (include written justification): No modifications to the City or County code are being requested for this project. • Distance in feet from the wetland or stream to the nearest area of work (for projects within 100 feet of a stream or wetland): The project will encroach upon Wetland E and Wetland F (see Impacts and Mitigation Plan, The Watershed Company, 2018) and will come within 2’ to 6’ feet of Thunder Hills Creek and the remaining wetlands identified in the Stream and Wetland Delineation Report (The Watershed Company, 2015). No work will be conducted within Thunder Hills Creek itself. Grading in Wetlands E and F is due to the increasing need to stabilize the area surrounding Thunder Hills Creek. Proposed improvements have been kept as minimal as possible. Temporary and permanent impacts to wetland and stream buffers will be mitigated on site utilizing the planting schedule noted in the Impacts and Mitigation Plan (included in SEPA package submittal), as well as provide wetland mitigation banking or in lieu of fee for mitigation of the unavoidable permanent impacts to wetlands and their buffers. • For projects located within 200 feet of Black River, Cedar River, Springbrook Creek, May Creek and Lake Washington, please include additional information: Not applicable, project is farther than 200 feet from these water bodies. Best Regards, Kristi Rettmann Environmental Scientist Phone: (425) 289-7338 kristi.rettmann@stantec.com Attachment: None c. Brian Wolf Wayne Wright