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I <br /> Stormwater Management Report Everett, WA <br /> I <br /> Dimensions Dimensions Dimensions at <br /> TESC Basin 10-yr 24-hr Required at Top of at Bottom Top of Pond <br /> Discharge Surface Area Sediment Storage <br /> (3:1 L:W Ratio) of Pond <br /> Narbeck Creek 1.5186 cfs 1,900 sf 25.5' x 76.5' 7.5' x 58.5' 49.5' x 100.5' <br /> 1,912 sf 5 <br /> ' Powdermill Gulch Creek 1.2079 csf 1,512 sf 22.5' x 67.5' <br /> 1,518 sf 4.5' x 49.5' 46.5' x 91.5' <br /> The outlet from the sedimentation pond shall be a solid riser pipe with two one-inch <br /> diameter dewatering holes located at the top of the sediment storage depth. The outlet <br /> should be connected to the existing storm system for conveyance to the existing outfalls <br /> into their respective creeks. <br /> Vehicle tracking of mud off-site shall be avoided. A gravel construction entrance will be <br /> installed on the site. This entrance will be located in the middle of the site off 23`d Drive <br /> W. This entrance is a minimum requirement and may be supplemented if tracking of mud <br /> onto streets becomes excessive. <br /> Stormwater shall be detained on-site during construction in a stormwater pond. The <br /> contractor shall construct interceptor swales and the detention pond to keep stormwater <br /> from leaving the site. The contractor will be responsible to adhere to NPDES permit <br /> requirements. <br /> C. Permanent Erosion Control and Site Restoration <br /> Grass or ground cover will be planted on all exposed areas with side slopes of 3H:1V or <br /> greater. <br /> 1 D. Inspection Sequence (weekly and after major rainfalls) <br /> E. Control of Pollutants Other Than Sediments <br /> Pollutants shall be controlled on the work site with a Fuel Management Area per the <br /> Department of Ecology. This shall include a centralized area for equipment, concrete <br /> truck washing and temporary storage of debris and stockpiled materials. <br /> F. Utilities <br /> New utilities will be coordinated with the individual utility contacts. Erosion and sediment <br /> controls will be sequenced for construction activities to ensure erosion and sediment <br /> transport does not occur during utility installation. Temporary systems are not to be <br /> 1 removed until permanent systems "on-line" and approved by inspector. <br /> I <br /> I <br /> PACLAND Job# 50108001 Page 12 <br />