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HomeMy WebLinkAboutSDP201500007 Calculations Final Site Plan and Comps. 2015-12-29 ENGINEERING CALCULATIONS CHAPTER 5 Table 5-14 Water Quality BMP Pollutant Removal Efficiencies Water Quality BMP* Target Pollutant Removal Efficiency Percent Impervious Cover Vegetated filter strip 10% 16-21% Grassed swale 15% Constructed wetlands 30% Extended detention(2 x WQ Vol) 35% 22-37% Retention basin I(3 x WQ Vol) 40% Bioretention basin 50% Bioretention filter 50% Extended detention-enhanced 50% 38-66% Retention basin II(4 x WQ Vol) 50% Infiltration(1 x WQ Vol) 50% Sand filter 65% Infiltration(2 x WQ Vol) 65% 67-100% Retention basin III(4 x WQ Vol 65% with aquatic bench) *Innovative or alternative BMPs not included in this table may be allowed at the discretion of the local program administrator, the plan approving authority,or the Department 5-106