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HomeMy WebLinkAbout26IWC6 - Drainage Report STORMWATER MANAGEMENT REPORT PREPARED FOR LINDO CONSTRUCTION, LLC 90 Maple Ave. Montville, Conn. BY WENTWORTH CIVIL ENGINEERS, LLC 177 WEST TOWN STREET LEBANON, CONNECTICUT 06249 DATE: 4-06-20 REV. 11-09-20 REV. 2-03-21 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 WENTWORTH CIVIL ENGINEERS LLC 177 West Town Street Lebanon, Connecticut 06249 Tel. (860) 642-7255 Fax. (860) 642-4794 Email: Wes@WentworthCivil.com WATER QUALITY VOLUME CALCULATIONS PREPARED FOR LINDO CONSTRUCTION, LLC 90 MAPLE AVE. MONTVILLE, CT DATE: 5-20-20 REV. 2-03-21 AREA = 339,607 SF IMPERVIOUS AREA = 128,502 SF : I = .38 WQV=1”((.05+(.9)(.38)) x 339,607 sf / 12” = 11,094 cf FROM STORMWATER CALCULATION POND DESIGN: DEPTH OF WQV (MINIMUM BASIN BOTTOM TO LOW FLOW OUTLET): 1.7 ft VOLUME PROVIDED BELOW LOW LEVEL OUTLET: 14,000 cf VOLUME PROVIDED ABOVE LOW LEVEL OUTLET AND BELOW OUTLET STRUCTURE TOP OF FRAME: 40,000 cf SEDIMENT FOREBAY (10% WQV): 1,109 cf (MIN.) SEDIMENT FOREBAY VOLUME PROVIDED: 2,500 cf Treatment methods of first 1” rainfall from impervious areas (WQV) that falls on proposed roof, walk and pavement areas will be collected by drainage system and discharged to the onsite Infiltration / Detention Basin and stored during small storms of 1” or less. This volume of water will percolate into the bottom of the infiltration basin over a period up to 24 hours. 50 51 52 53 54 55 56 57 58 1 inch = ft. ( IN FEET ) (APPROXIMATE ONLY) W E N T W O R T H C I V I L E N G I N E E R S LL C TE L . ( 8 6 0 ) 6 4 2 - 7 2 5 5 FA X ( 8 6 0 ) 6 4 2 - 4 7 9 4 we b : w e n t w o r t h c i v i l . c o m 17 7 W E S T T O W N S T . LE B A N O N , C T 0 6 2 4 9 W 60 60 0 60 120 1 inch = ft. ( IN FEET ) (APPROXIMATE ONLY) 6003000300 300 1 inch = ft. ( IN FEET ) (APPROXIMATE ONLY) 6003000300 300