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HomeMy WebLinkAboutSW8120209_COMPLIANCE_20120322STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW DOC TYPE ❑ CURRENT PERMIT ❑ APPROVED PLANS ❑ HISTORICAL FILE CO COMPLIANCE EVALUATION INSPECTION l DOC DATE YYYYMMDD SAND FILTER DESIGN Closed FILENAME: S:IWQSlStormwaterlpermits & projects1YR1120209 HI)i mo excel_SF 120209 Initial Run Date: 8-Mar-12 Reviewer: csb Last modified: 22-Mar-12 Project Number SW8 120209 PROJECT NAME: Center for Public Safety Sand Filter # 1 2 3 4 5 6 7 Receving Stream New River New River New River Now River New River Now River New River Classification 58.HQW,NSW 53,HQW;NSW SB.HQW,NSW SB,HQW,NSW SB;HQW.NSW SB,HQW;NSW S3,HQW;NSW Index Number 19-(10.5) 19-(10.5) 19-(10.5) 19-(10.5) 19-(10.5) 19-(10.5) 19-(10.5) Onsite DA 47559 61263 56996 35806 24699 23740 9017 sf Offsite DA sf Total DA 47559 61263 58998 35806 24699 23740 9017 sf Total DA acres 1.09 1.41 1.35 0.82 0.57 0.54 0.21 ac. Buildings 24002 19711 9017 sf Parking/Street 14461 29666 37660 27748 20125 17293 sf Concrete 3180 3296 1065 sf Other 2413 sf Offsite sf Total BUA 41643 55086 38725 27748 20125 17293 9017 sf Runoff Cc 0.87 0.88 0.71 0.79 0,82 0.78 0.98 REQUIRED VOLUME CALCULATIONS %impervious 87.56% 89.92% 65.64% 77.50% 81.48% 72.84% 100.00% % Rv factor, pro 0.05 0.05 0.05 0.05 0,05 0.05 0.05 -77 Rv factor, post 0.838 0.859 0.641 0.747 0.783 0.706 0,950 Design Storm 1.50 1.500 1.500 1,500 1.500 1.S00 1.500 in 1.5" volume 4982 6580 4725 3345 2418 2094 1071 cf 1 yr24 hr precip depth in 1 yr 24 hr pre vol N/A N/A N/A N/A N/A N/A N/A cf 1 yr 24 hr post vol N/A N/A N/A N/A N/A N/A N/A cf Post - Pre N/A N/A Ni N/A N/A N/A N/A cf Total WQV 4982 6580 4725 3345 2418 2094 1071 cf WQV to store 3737 4935 3544 2509 1814 1570 803 cf REQUIRED SURFACE AREAS Designer's hmax 2.50 2.53 2.50 2.50 2.56 2.50 2.50 ft As+Afrequired 1495 1951 1418 1004 709 628 321 sf Min. As 329 434 312 221 160 138 71 sf Depth of Sand Bed 1.50 1.5 1.5 1.5 1.5 1.5 1.5 ft Min. Af 468 614 444 314 225 197 101 sf SURFACE AREAS & VOLUME PROVIDED CALCULATIONS As provided 1082 1578 958 710 462 462 231 sf Af provided 494 618 494 370 246 246 123 sf As+Afprovided = 1576 2196 1452 1080 708 708 354 sf Min. As+Af rov? OK OK OK OK NO OK OK Sed. Ch. Drain? NO Y or N Weirelevation 11.08 10.1 11.15 12.38 12.4 10.53 10.44 fmsl Bypass/Spillway 1358 12.63 13.65 14.98 14,96 13.03 12.94 fmsl Top of Sand Elev. 11.08 10.1 11.15 12.38 12.4 10.53 10,44 Hmax provided 2.3709143 2.24729124 2.44075413 2.32322049 2,56189751 2.2180482 2.26857786 Hmax Met? NO NO NO NO YES NO NO Bottom of Sed. Ch. 9.58 8.6 9.65 10.88 109 9,03 8.94 Volume provided 2705 3992 2395 1775 1183 1155 578 of Min. Vol. Prov? NO NO NO NO NO NO NO DRAWDOWN CALCULATIONS 1yr24hr storm intensity in/hr 1y24 hr pre -peak flow 0 0 0 0 0 0 0 cfs Orifice Diameter 4 4 4 4 4 4 4 in Orifice Area 0,087 0.087 0.087 0.087 0.087 0.087 0.087 sf Avg H on Orifice 2.17 2,19 2.17 2,17 2.21 2,17 2.17 ft Min. 40 hour flowrate 0.03 0.0S 0.03 0.02 0.02 0.01 0.01 cfs Orifice flow rate 0.542 0.546 0.542 0.542 &549 0.542 0.542 cfs Time to drawdown 1.9 2.5 1.8 1.3 0.9 0.8 0.4 hrs