Drainage Report

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 100-Year Rainfall=8.66" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 39 Summary for Pond 17P: Porous pavement system 4 Inflow Area = 1.968 ac, Inflow Depth = 7.59" for 100-Year event Inflow = 14.11 cfs @ 12.15 hrs, Volume= 1.245 af Outflow = 5.25 cfs @ 12.34 hrs, Volume= 0.858 af, Atten= 63%, Lag= 11.5 min Primary = 5.25 cfs @ 12.34 hrs, Volume= 0.858 af Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.03 hrs Peak Elev= 591.49' @ 12.34 hrs Surf.Area= 10,178 sf Storage= 27,199 cf Plug-Flow detention time= 261.4 min calculated for 0.858 af (69% of inflow) Center-of-Mass det. time= 154.3 min ( 913.8 - 759.5 ) Volume Invert Avail.Storage Storage Description #1 585.00' 32,044 cf Custom Stage Data (Prismatic) Listed below (Recalc) 81,424 cf Overall - 1,315 cf Embedded = 80,109 cf x 40.0% Voids #2 586.00' 1,315 cf 36.0" Round Pipe Storage Inside #1 L= 186.0' 33,358 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 585.00 10,178 0 0 593.00 10,178 81,424 81,424 Device Routing Invert Outlet Devices #1 Primary 588.95' 6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 589.90' 24.0" W x 4.0" H Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=5.25 cfs @ 12.34 hrs HW=591.48' (Free Discharge) 1=Orifice/Grate (Orifice Controls 1.43 cfs @ 7.28 fps) 2=Orifice/Grate (Orifice Controls 3.82 cfs @ 5.73 fps)