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Home My WebLink AboutSW8060826_COMPLIANCE_20060815STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW�(�a� DOC TYPE El CURRENT PERMIT ❑ APPROVED PLANS ❑ HISTORICAL FILE 5 COMPLIANCE EVALUATION INSPECTION DOC DATE WYYMMDD Red Fish Gnlle Stormwater Hydrologic and Hydraulic Calculations August 2006 SEAL = 0,30'3;( N G I C-1�ti rH 11IMtti1ti+�, RECEIVED AUG 15 2006 DWQ -QOJ # sw -66( on60 Pxepared by East Coast Engineering Company, P.A. Consulting Engineers 5hallotte, North Carolina 28459 Post Office Box 2469 4918 Main Street Office 910 754 8029 RED FISH GRILLE Wet Detention Basin Calculations East Coast Engineering Company, PA JCR Pond 1 Drainage Area (DA) = 70,377 sf or 162 ac lm ervious Area 1A = 37,788 sf 0 87 ac Percent Impervious I) INDA 0 537 or 53 7% SAIDA, 90% TSS (no vegetative filter req'd) Pond Depth = 3 5 00537 or 5 37% Min req`d SA @ PP (SAIDA)x(DA) 3,779 sf Min req'd storage volume Rv = 0 05 + (0 009 x 1) = 0 533 Volume = 1 in x 1 ft 1 12 in x Rv x DA 3,127 34 cf SA provided PP Oval Pond Elev = 115 1 3,910 sf Enough SAprovided? YES Min storage de th re 'd Min storage volume 1 SA provided @ PP 0 80 ft Storage depth set at 1 ft Elevation of temporary ool 116 ft SA @ Temporaty pool 4,769 sf Storage volume rovided Average of SA temp pool & PP x storage depth 4,339 50 cf OK Outlet Sizing Q - 2 day drawdown time Min re 'd storage volume x 1 in 12 days) 0 018 cfs Q - 5 day drawdown time Min re 'd storage volume x 1 in / 5 days) 0 007 cfs Height h 112 Min Storage Depth) 0 50 ft co Constant 06 Required Area for Q-2 A = QI(C x (2 h) 0 77 in Re uired Area for Q-5 A = QI C x (2 h 0 31 in Onfice Choosen 0 75 in CHECK Area Provided by Orifice Choosen A = n 0 44 in Area Provided by Orifice Choosen 0 003 ft The Average head h = 1/2(Temporary Pool depth - 112 onflce diameter 5 8125 in The Average head 0 484 ft Q provided Q = Ca(2 h) 0 010 cfs OK LOF Revision Date 8/14/2006 RED FISH GRILLE POND VS FOREBAY East Coast Engmeering Co , PA JCR POND 1 VOLUME TO FOREBAY COMPARISON FOREBAY 2 1 SLOPE BOTTOM SF 36111 SURFACE SF 706161 DEPTH 2 VOLUME 1067 POND DEPTH 351 3 1 SLOPE BOTTOM SF 400 TOP SF 1246 DEPTH 1 9 VOLUME 1564 6 1 SLOPE BOTTOM SF 1246 SURFACE SF 3910 DEPTH 1 6 VOLUME 4125 TOTAL POND VOLUME 5689 FOREBAY % OF POND 18 8% OF !;- 8/8/2006 RED FISH GRILLE STORM DRAINAGE FLOW CALCULATIQNS East Coast Engineering Company, PA JCR Q FROM DA1 Drainage Area = 21,460 SF Drainage Area = 0 49 Acres Design Storm = 10 -YR storm Surface Acres C-Value rt� GRASSY 023 02 IMPERVIOUS 026 09 Total'A' 0492653811 Weighted 'C' D 567 Intensity ' i ' (3) 71 QI = C zA 1 98 cfs Q FROM DA3 Drainage Area = 7 660 SF Drainage Area = 018 Acres Design Storm = 10 -YR storm Surface Acres C-Value GRASSY 000 02 IMPERVIOUS 018 09 Total A' 0175849403 Weighted 'C' 0 900 Intensity'z' {3J 7 1 Q, = C zA 1 12 cfs Q FROM DA2 Drainage Area = 10,835 SF Drainage Area = 025 Acres Design Storm = 10 -YR storm Surface Acres C-Value 01 GRASSY 000 02 IMPERVIOUS 025 09 Total 'A' 025 Weighted 'C' 0 900 Intensity 'z'(3) 1 Q, = C zA b9 cfs Q FROM DA4 Drainage Area = 8,049 SF Drainage Area = 0 18 Acres Design Storm = 10 -YR storm Surface Acres C-Velue 111 GRASSY 000 02 IMPERVIOUS 018 09 Tota! A' 018478 Weighted 'C' 0 900 Intensity ' z ' (3) 7 1 Q, = C zA 1 18 cfs 3 OF T Revision Date 8/1412006 REDFISH GRILLE CULVERT CALCULATIONS f East Coast Engineering Company, PA JCR PIPE FLOW PIPE INVERT Total Q CONTRIBUTION SIZE IN INVERT OUT LENGTH PIPE TOP IN PIPE TOP OUT BOX RIM IN BOX RIM OUT COVER CHECK IN COVER CHECK OUT SLOPE Q MAX CHECK SDI 3 11 vN2TjDA1#DA3M 15 114 39 114 10 64-'000 115 75 11546 116 75 11750 100 2 04 0 5% 4 71 OK SD2 588 J:SD1+DA2+DA4 18 1 114 10 14-VE,,�SD2-tMgj18 1 1135013,1--507000PI 11574 1 115 14 1 118 00 1 11600 1 226 1 086 1 1 2% 1246 1 OK SD3 588 113 50 1 112 55 ill92-000, 115 14 1 114 19 1 118 00 1 11500 1 286 1 081 1 0 5% 800 1 OK OF :5— Revision Date 818=06 DA-4 DA-2 DA- I DA-2 DRAINAGE AREA MAP I FOR RED FISH GRILLE DA-3 S OF