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Notched Grade Board Trench <br /> For roof areas larger than 700 ft2,dispersion trenches with notched grade boards may be used with <br /> a total length not to exceed 50 ft. <br /> Notched Grade Board Trench Length(ft) = (10 ft)*(Roof Area to Trench(ft2)) <br /> 700(ft2) <br /> • Notched grade board trench length required: <br /> If greater than 50 feet needed more than one trench will be required <br /> • Number of notched grade board trenches required: <br /> • Length of each notched grade board trenches: <br /> El See attached sketch. <br /> Splashblocks <br /> Splashblocks shall be designed in accordance with the SWMMWW.A maximum of 700 ft2 of roof <br /> area can drain to a single splashblock. <br /> • Roof area requiring mitigation: <br /> • Roof area discharging to splashblock: <br /> ❑ See attached sketch. <br /> BMP T5.10C Perforated Stub-out Connections <br /> Perforated stub-out connections shall be designed in accordance with the SWMMWW. <br /> • Roof area requiring mitigation (ft2): <br /> • Roof area discharging to perforated stub-out connection: <br /> • Perforated pipe length(ft): <br /> Perforated Pipe Length(ft) _ (10 ftl*(Roof Area to Facility(ft2)) <br /> 5000(ft2) <br /> The minimum perforated pipe length shall be 10 ft. <br /> City of Everett Public Works <br /> Small Project Stormwater Site Plan Report-Dec 2019 40 <br />