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1 <br /> VIII. Permanent Stormwater Control Plan <br /> 1 <br /> The following section details the selection of stormwater control BMPs and facilities that <br /> ' will serve the proposed project in its developed condition. The selection of stormwater <br /> control and BMP facilities follows the 2012 DOE Manual and the 2010 City of Everett <br /> Stormwater Management Manual. <br /> A. Offsite Analysis <br /> There are is no upstream drainage because the ridgeline bisecting the site is the bank of <br /> the Snohomish River. Site drainage generally sheet flows to the northeast and <br /> concentrates in an existing ditch system which conveys runoff northward for <br /> ' approximately 1,300 feet through a combination of ditches and culverts where it <br /> ultimately discharges into the Snohomish River. <br /> B. Pre-Developed Site Hydrology <br /> The site is currently a fenced gravel storage yard and parking area and mounded with <br /> about 10 feet of river dredge spoils. The Snohomish River bank bisects the site in a northwest <br /> to southeast direction, such that the river bank slope is approximately 17 percent and the slope <br /> from top of bank toward Ross Avenue is approximately 3 percent. Drainage can be characterized <br /> as sheet flow on each side of the bank. If surface water accumulates on the northeast side of the <br /> bank it will flow northward to the ditch along Ross Avenue. Stormwater within the ditch will <br /> flow in a northwest direction and eventually discharge into the Snohomish River. <br /> ' The project site consists primarily of river dredge soils and the USDA Soil Conservation <br /> Service has classified as Urban Land. A Hydrologic Soil Group has not been assigned <br /> due to limited data on the USDA Soil Survey website; however, soils from adjacent <br /> ' properties on Smith Island are classified as Puget Silty Clay Loam, Type C soils and are <br /> assumed as the native condition of the soil for the project site. <br /> ' C. Developed Site Hydrology <br /> The proposed project involves the construction of a non-ferrous metal fabrication shop and office <br /> ' encompassing a gross building area of 12,750 square feet with associated asphalt paving and <br /> landscaping, an approximately 17,850 square foot wharf consisting of a crane pad and dock, and <br /> the creation of an approximately 0.15 acre estuarine wetland to mitigate for the shade related <br /> ' impacts created by the proposed wharf Due to sites location adjacent to the Snohomish River no <br /> detention is proposed. <br /> The project development area consists of approximately 1.95 acres and includes 12,750 square <br /> feet(0.29 acre)of coated metal rooftop area and 24,105 square feet(0.55 acres)of pavement used <br /> for parking and storage surrounding the shop and office building. An additional 17,850 square <br /> 1111 feet(0.41 acres) is proposed for the wharf. The remaining development area consists of previous <br /> Stormwater Site Plan Page 16 <br /> McClean Ironworks Site Improvements August 2014 <br />