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I <br /> Stormwater Management Report Everett, WA <br /> ' Detention Volume Calculations: <br /> ' Per the Everett Stormwater Management Manual figure 1-3.1 Volume Correction Factor for <br /> Streambank Erosion Control BMPs, and the percentage of the site and the NCC property <br /> that is impervious of 84%, a volume correction factor of 1 .44 shall be applied to detention <br /> facility. <br /> ' Correction Factor = 1 .44 <br /> Design Volume = 34,053 cf <br /> Required detention volume = 34,053 x 1 .44 =49,036 cf <br /> Provided detention volume = 50,070 cf (volume calculated from design contours) <br /> tWater Quality <br /> ' A wetpond has been utilized to provide water quality. The wetpond has a permanent pool <br /> volume equal to the runoff generated by the 6-month, 24-hour storm using the developed <br /> conditions. The wetpond shall be constructed to the standards set forth in section 3-3.5.1 <br /> ' in the Everett Stormwater Management Manual. <br /> Required Treatment volume = 0.4336 Acre-fee (see page 11) = 18,888 cf <br /> ' Treatment volume provided = 20,806 cf <br /> Volume provided in open water cell (Cell 1) = 14,592 CF (70% - 85% maximum) <br /> Volume provided in wetland treatment cell (Cell 2) = 6,214 CF (30% - 15% minimum) <br /> 1 <br /> 1 <br /> 1 <br /> PACLAND Job # 50108001 Page 18 <br />