Drainage Report

basin 4 with exfiltration Proposed basin 4 R4 with exfiltration NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/23/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 9 Summary for Pond 17P: Porous pavement system 4 Inflow Area = 1.968 ac, Inflow Depth = 2.64" for 2-Year event Inflow = 4.96 cfs @ 12.15 hrs, Volume= 0.432 af Outflow = 0.07 cfs @ 23.24 hrs, Volume= 0.409 af, Atten= 99%, Lag= 665.3 min Discarded = 0.07 cfs @ 23.24 hrs, Volume= 0.409 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.03 hrs Peak Elev= 588.20' @ 23.24 hrs Surf.Area= 10,178 sf Storage= 13,655 cf Plug-Flow detention time= 1,551.5 min calculated for 0.409 af (95% of inflow) Center-of-Mass det. time= 1,520.0 min ( 2,293.4 - 773.3 ) 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 Discarded 585.00' 0.310 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = -7.00' #2 Primary 588.95' 6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Primary 589.90' 24.0" W x 4.0" H Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.07 cfs @ 23.24 hrs HW=588.20' (Free Discharge) 1=Exfiltration ( Controls 0.07 cfs) Primary

C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.07 cfs @ 23.24 hrs HW=588.20' (Free Discharge) 1=Exfiltration ( Controls 0.07 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=585.00' (Free Discharge) 2=Orifice/Grate ( Controls 0.00 cfs) 3=Orifice/Grate ( Controls 0.00 cfs)