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Stormwater Pollution Prevention Plan <br />Big J's and the Index site will be developed into gravel parking lots as a temporary condition. <br />The final condition will be determined at a later date. <br />Construction activities will include site preparation, installation of temporary er•osion and <br />sediment control measures per the construction temporary erosion and sediment control plan <br />(TESCP), demolition of site features and existing utilities, excavation for the basement and <br />building foundations, poured concrete foundations, and building construction. The scheduling <br />and phasing of BMPs during construction is provided in Section 4.0. <br />The permanent storm system will consist of catch basins and storm drain pipe to collect and <br />convey stormwater around the proposed building. A new storm drain manhole will be located on <br />the existing storm line that discharges to the combined sewer line. The storm system will <br />connect to this manhole, and the existing storm line that runs under the proposed building will be <br />demolished. <br />Per the requirements of the City of Everett Public Works Policy No. 2-11, runoff from the <br />proposed development must match runoff of the existing site conditions for sites discharging to <br />the combined sewer system. The building and Index sites will decrease impervious area from <br />existing and therefore detention is not required, however the Big J's site will increase impervious <br />area and a detention pond will be provided for permanent flow control. <br />The settling tank or pond will be used during construction was designed using the 2-year storm <br />since the construction will not occur over a long time-frame (approximately two years). <br />Construction stormwater shall be discharge to the public combined sewer system under approval <br />from the City of Everett. <br />The following summarizes details regarding site areas for the WSU NPSE building site: <br />Total site area: <br />Percent impervious area before construction: <br />Percent impervious area after construction: <br />Disturbed area during construction: <br />1.87 acres <br />91% <br />75 % <br />1.87 acres <br />Disturbed area that is characterized as irnpervious (i.e., <br />access roads, staging, parking): 1.87 acres <br />2-year stormwater runoff peak flow prior to construction <br />(existing): 0.67 cfs <br />10-year stormwater runoff peak flow prior to construction <br />(existing): 1.03 cfs <br />