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HomeMy WebLinkAboutPN_Project_Narrative_181221_v1December 21, 2018 Page 1 of 3 PROJECT NARRATIVE Grade and Fill Permit Project name, size, and location of site: The Upper Balch Pit project is located within the City of Renton at 301 Monroe Avenue NE. More generally the site is located in the NE ¼ of the NW ¼ of Section 16 of Township 23 North, Range 5 East, in King County, Washington. The total project site consists of one parcel (KC tax parcel no. 1623059059) with an area of approximately 14.4 acres. Land use permits required for proposed project: The following land use permits are required for the proposed project: • Grade and Fill Permit (City of Renton) Zoning designation of the site and adjacent properties: The project site is zoned R-10. The Comprehensive Plan designation for the project site is Residential High Density. Property to the north is zoned CA, property to the east is zoned R-8, and property to the west and south is zoned IL. Current use of the site and any existing improvements: The project site has been used as an upland fill and reclamation site since 1982. It was used as a permitted sand/gravel pit from 1962 to 1982 under the name, “Upper Balch Pit.” The property currently has a valid Grade and Fill permit (#LUA10-056) which allows the pit to be filled to an elevation of 325 feet. There is a chain-link fence around the perimeter of the property and a partially paved road leading into the pit. Special site features: Power lines run through the northeast portion of the site in a 150’ wide Puget Sound Energy Easement (AF #3425304 and #2571770). The City of Renton currently discharges stormwater to the site through a Temporary Storm Drainage Easement (AF# 2007092800176), where the runoff infiltrates on-site. The easement will terminate once the pit is filled to an elevation of 325 feet. At or before this time, it is expected the storm pipes will be removed. City of Renton interactive maps identifies a possible wetland on-site. However, a wetland reconnaissance of the property performed by Raedeke Associates, Inc. concluded that the property contains no areas that exhibit wetland characteristics. City of Renton interactive maps also identify areas of steep slopes. Most of the slopes around the perimeter are by definition a landslide hazard. These manmade steep slopes will be removed as the pit is filled under the approved grade and fill permit which allows the pit to be filled to an elevation of 325 feet. The new Grade and Fill Permit is sought to authorize fill above 325 feet to prepare the site for potential future development. December 21, 2018 Page 2 of 3 Statement addressing soil type and drainage conditions: The pit is located in the eastern uplands of Renton in glacially altered terrain. Material removed from the site consists of recessional outwash deposited by melt water from the Vashon glacier and consists of sand and gravel with zones of fine to medium-graded sand. The granular material was mostly removed down to a clayey silt layer (Lacurstine deposit) or in places glacial till, which typically overlies the silt material. Slopes at the boundaries of the pit were generally cut at or near the angle of repose and have remained reasonably stable. Stormwater runoff from the site currently flows to the bottom of the pit where it then infiltrates. No runoff flows off-site. It is anticipated that stormwater runoff from a future residential development will be infiltrated in the northwest portion of the site. Field testing by the project Geotechnical engineer was completed and summarized in a report dated November 9, 2018. Based on results of grain size distribution testing, the report recommended a preliminary design infiltration rate of 7 in./hr for stormwater facilities. Proposed use and scope of the proposed development: The project proposes the continue filling the pit to support an anticipated residential development. Final grades will be at or near the existing grades of the surrounding streets and land area. The applicant requests the permit be valid for a maximum of 10-years. The future development will be required to provide Basic Water Quality treatment in addition to the Flow Control Duration Standard matching forested conditions. It is anticipated these will be provided through the use of a wetpond and infiltration trench. The proposed grading plan includes these facilities which have been preliminarily sized based on a conceptual site plan. The infiltration trench has been sized to fully infiltrate all stormwater runoff. In order to protect the infiltration facility from the intrusion of soil fines, construction stormwater will be routed to a temporary sediment pond. Access: The project site is fronted by Monroe Ave NE to the east, NE 2nd St to the south, and Jefferson Ave NE to the west. NE 2nd St and Jefferson Ave NE are private streets with no public right-of-way adjacent to the project site. The site is currently accessed through a gate located along Jefferson Ave NE. This location is expected to remain as the point of access to complete the proposed grade and fill activity. Vehicular access to the potential future residential development is anticipated to be provided by Monroe Ave NE. Proposed off-site improvements: No off-site improvements are proposed for the Grade and Fill Permit. Future development would likely require frontage improvements along the adjacent roadway frontage of Monroe Ave NE. Jefferson Ave NE and NE 2nd Street are currently private roads serving the Transfer Station and KC Roads facility. Total estimated construction cost and estimated fair market value of the proposed project: N/A Estimated quantities and type of materials involved if any fill or excavation is proposed: Grading and filling activities are proposed to prepare the site for the potential residential development. Fill from local sources will be used for the balance of the fill efforts such as crushed base courses, gravel backfill, trench backfill, and asphalt pavement (as required). Estimated quantities for structural fill on-site is December 21, 2018 Page 3 of 3 approximately 230,000 cubic yards of fill material. Imported fill materials will be provided from an approved source. Number, type and size of any trees to be removed: There are 24 total trees above elevation 325. Existing trees below this elevation will be removed as part of the existing Grade and Fill permit (#LUA10-056) which allows the pit to be filled to an elevation of 325 feet. 13 trees above elevation 325 are proposed to be removed with this project due to the filling and grading activity. These 13 trees are located at elevations below the proposed finished grades of the site. Tree replacement is not expected to be required per the submitted City of Renton Tree Retention Worksheet. Explanation of any land to be dedicated to the City: Right-of-way dedication is not expected to be required along the frontages of Monroe Ave NE, NE 2nd St, and Jefferson Ave NE as part of the Grade and Fill Permit. Any such dedication that might be required would be associated with future development. Any proposed job shacks, sales trailer, and/or model homes: The existing job shack on-site is proposed to remain until fill operations are completed. Any proposed modifications being requested (include written justification): None proposed.