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• s <br /> 7 � <br /> Worksheet 3 BMP Sizing Worksheets <br /> DISPERSON BMPS <br /> BMP T5.11 Concentrated Flow Dispersion <br /> Concentrated flow dispersion BMPs shall be designed in accordance with the SWMMWW. Clearly show the <br /> vegetated flowpath on the site plan. A maximum of 700 ft2 of roof area can drain to each dispersion BMP. <br /> • Hard surface area requiring mitigation: <br /> • Hard surface draining to dispersion BMP:_ <br /> • #of dispersion BMPs: Total Hard Surface = <br /> 700 ft2 <br /> • Dispersion trench required? ❑ Yes ❑ No <br /> (must be included if flow path is 25 to 50 ft) <br /> BMP T5.12 Sheet Flow Dispersion <br /> Sheet flow dispersion BMPs shall be designed in accordance with the SWMMWW. <br /> • Hard surface area requiring mitigation: <br /> • Width of paved surface discharging into sheet flow dispersion BMP: <br /> • Minimum required width of vegetated buffer: _ <br /> (10 ft for every 20 ft of paved/hard surface,or fraction there of) <br /> BMP T5.30 Full Dispersion <br /> Full dispersion BMPs shall be designed in accordance with the SWMMWW. <br /> • Residential (impervious surfaces). All calculations are for areas with a single Threshold Discharge <br /> Area (TDA). If multiple TDAs exist,provide a calculation for each. <br /> Total Impervious(ft2)*100%= _% (must be less than 10%to use BMP) <br /> Total Area(ft2) <br /> • Required Dispersion Area(ft2) =Total Impervious Area(ft2)*6.5 <br /> Required Dispersion Area(ft2)*6.5= ft2 <br /> • Dispersion area provided: <br /> (Note:Dispersion area must be preserved as forest or native vegetation.) <br /> City of Everett Public Works <br /> Small Project Storm water Site Plan Report-Dec 2019 37 <br />