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1 <br /> I <br /> Minimum Requirement#4: PRESERVATION OF NATURAL DRAINAGE <br /> SYSTEMS AND OUTFALLS <br /> Runoff from the development areas of the site will be dispersed and will infiltrate on site. The <br /> berm at the west end of the project will be the final BMP to insure that the drainage returns and <br /> is dispersed to the existing outflow in the same manner it took place prior to this development. <br /> The proposed site development is not expected to have off-site drainage impacts. This project <br /> will disperse runoff into the natural ground on site (second growth forest) thus recharging the <br /> ground water. <br /> Minimum Requirement#5: ON-SITE STORMWATER MANAGEMENT. <br /> The SWPPP plan and the drainage plans have been developed to use the current BMP's to <br /> provide infiltration, retain and disperse stormwater runoff on site to the maximum extent feasible <br /> I without causing offsite flooding or erosion impacts. The stormwater management BMP's in <br /> volume III, Chapter 12 are provided to reduce hydrologic disruption of the developed site. <br /> BMP 12.20, Post-Construction Soil Quality and Depth-Natural occurring(undisturbed) soil and <br /> vegetation provide important stormwater functions including infiltration,pollution absorption, <br /> and sediment control. These functions are lost when development strips away native soil and <br /> vegetation and replaces it with minimal topsoil and sod. This project requires the replacement of <br /> topsoil and amended soil in any area where bare soil remains as a result of the project <br /> development. These areas will require replacement of top soil with amended soil meeting the <br /> requirements of City of Everett Stormwater Management Manual,Volume I. This will stabilize <br /> the soil and prevent erosion for the final construction phase. The contractor will still need to use <br /> the proper BMP's for temporary erosion control such as BMP C 120: Temporary and Permanent <br /> Seeding,BMP C123 Plastic Covering, etc, during the construction of the site. <br /> Minimum Requirement#6: RUNOFF TREATMENT <br /> All available means to remove pollutants from stormwater flows are active in the proposed <br /> raingarden. The removal processes provided are as follows: <br /> • Sediment removal. Sedimentation will occur within the Type "A" catch basins, located <br /> within the proposed private road, that direct road runoff to each individual rain garden. <br /> Oil/Water separation. A.frop-tee oil/water separator will be located in each catch basin <br /> leading to each individual rain garden. This will ensure that all runoff from pollutant <br /> generating surfaces, namely the private road and driveways, encounter 1 or more <br /> oil/water separation devices before discharging to the wetland buffer. <br /> S <br /> 1 <br />