Drainage Report

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 27 Summary for Pond 17P: Porous pavement system 4 Inflow Area = 1.968 ac, Inflow Depth = 4.29" for 10-Year event Inflow = 8.03 cfs @ 12.15 hrs, Volume= 0.703 af Outflow = 0.70 cfs @ 13.35 hrs, Volume= 0.316 af, Atten= 91%, Lag= 72.3 min Primary = 0.70 cfs @ 13.35 hrs, Volume= 0.316 af Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.03 hrs Peak Elev= 589.75' @ 13.35 hrs Surf.Area= 10,178 sf Storage= 20,113 cf Plug-Flow detention time= 408.7 min calculated for 0.316 af (45% of inflow) Center-of-Mass det. time= 255.7 min ( 1,022.5 - 766.8 ) 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=0.70 cfs @ 13.35 hrs HW=589.75' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.70 cfs @ 3.56 fps) 2=Orifice/Grate ( Controls 0.00 cfs)