Stormwater Report

512-516 Pleasant Valley Way, West Orange 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Casey & Keller, Inc Printed 8/25/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC. Page 20 Summary for Pond 3: Pervious Pavers Inflow Area = 0.168 ac, 91.47% Impervious, Inflow Depth= 4.93" for 10-Year-2020 event Inflow = 0.92 cfs @ 12.06 hrs, Volume= 0.069 af Outflow = 0.16 cfs @ 12.47 hrs, Volume= 0.069 af, Atten= 83%, Lag= 24.5 min Discarded = 0.11 cfs@ 11.45 hrs, Volume= 0.067 af Primary = 0.05 cfs @ 12.47 hrs, Volume= 0.002 af Routed to Pond 5 : Pipes Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 414.63' @ 12.47 hrs Surf.Area= 1,620 sf Storage= 733 cf Plug-Flow detention time= 36.2 min calculated for 0.069 af (100% of inflow) Center-of-Mass det. time= 36.2 min ( 784.0 - 747.7 ) Volume Invert Avail.Storage _ Storage Description #1 413.50" 1,730 cf 60.00'W x 27.00'L x 2.67'H Prismatoid 4,325 cf Overall x 40.0% Voids Device Routing Invert Outlet Devices #1 ~~ Discarded 413.50' 2.900 in/hr Exfiltration over Surface area #2 ~~ Primary 414.50' 6.0" Round Culvert L=50.0' Ke= 0.200 Inlet / Outlet Invert= 414.50'/414.17' S= 0.0066‘ Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf iscarded OutFlow Max=0.11 cfs @ 11.45 hrs HW=413.53' (Free Discharge) 4=Exfiltration (Exfiltration Controls 0.11 cfs) Primary OutFlow Max=0.05 cfs @ 12.47 hrs HW=414.63' (Free Discharge) *_2=Culvert (Barrel Controls 0.05 cfs @ 1.76 fps) 27