1010 SE EVERETT MALL WAY NORTHWEST KIDNEY CENTER - EVERETT 2022-03-07

NKC Everett Everett, Washington Drainage Memorandum Element 3: Control Flow Rates As noted above, site demolition and improvements associated with this project will be limited, with less than 2,000 SF of land disturbed by the project. Existing vegetation is well established in the vicinity of the proposed site improvements and will be protected wherever possible to control the rates of runoff leaving the site. Flow rates are not anticipated to be significantly affected by the proposed construction activities. Element 4: Install Sediment Controls As described in previous sections, the majority of the property will remain paved or covered in well -established vegetation throughout construction, greatly reducing the risk sediment -laden runoff leaving the site and entering the storm system. As a precaution, the inlets and catch basins in the vicinity of the project will be protected from sediment using storm drain inlet protection per City of Everett Standard Plan 210. If necessary, the contractor will implement additional City of Everett Standard sediment control BMPs as necessary to prevent sediment from leaving the site, see Element 7 below for more information. Element 5: Stabilize Soils The proposed project involves only minor grading activities that will not result in soils being exposed for,extended periods of time. As described in previous sections, existing pavement and vegetation will be maintained to the maximum extent feasible, keeping soils covered and minimizing the risk of erosion. Element 6: Protect Slopes Based on the scope of the proposed site work, significant slopes are not anticipated as a part of this project, Element 6 is not applicable. Element 7: Protect Drain Inlets Storm drain catch basins and inlets will be protected per City of Everett Standard Plan 210. If necessary, additional inlet protection will be implemented through the use of the following BMPs: • City of Everett Standard Plan 212: Inlet Fabric Fence Filter • City of Everett Standard Plan 214: Temporary Silt Fence Element 8: Stabilize Channels and Outlets The existing site drains via sheet flow over paved surfaced to catch basins, which collect runoff before it is conveyed off -site. Channels and outlets will not be affected by the project; Therefore Element 8 is not applicable. Element 9: Control Pollutants The project is not anticipated to be a source of pollutants; Therefore Element 9 is not applicable. KPFF Consulting Engineers December 11, 2019 Page 2 of 4