Stormwater Report

512-516 Pleasant Valley Way, West Orange 1240815-pipes NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 37 Summary for Pond 5: Pipes Inflow Area = 0.360 ac, 72.63% Impervious, Inflow Depth = 4.99" for 100-Year-2020 event Inflow = 2.21 cfs@ 12.07 hrs, Volume= 0.150 af Outflow = 1.86 cfs@ 12.15 hrs, Volume= 0.150 af, Atten= 16%, Lag= 4.6 min Discarded = 0.03 cfs@ 7.55 hrs, Volume= 0.045 af Primary = 1.83 cfs@ 12.15 hrs, Volume= 0.105 af Routed to Link 7 : Proposed Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 414.09'@ 12.13 hrs Surf.Area= 400 sf Storage= 641 cf Plug-Flow detention time= 14.9 min calculated for 0.150 af (100% of inflow) Center-of-Mass det. time= 14.9 min ( 773.8 - 758.9 ) Volume Invert Avail.Storage Storage Description #1 411.50' 329 cf 10.00'W x 40.00'L x 3.00'H Prismatoid 1,200 cf Overall - 377 cf Embedded = 823 cf x 40.0% Voids #2 412.00' 377 cf 24.0" Round Pipe Storage x 3 Inside #1 L= 40.0' S= 0.0020 '/ 706 cf Total Available Storage Device Routing Invert Outlet Devices #1 ~~ Discarded 411.50' 2.900 in/hr Exfiltration over Surface area #2~=~— Primary 412.00' 12.0" Round Culvert L= 14.0' Ke= 0.100 Inlet / Outlet Invert= 412.00'/ 411.94' S= 0.0043 '/ Cc= 0.900 n= 0.012 Corrugated PP, smooth interior, Flow Area= 0.79 sf #3 =~ =©Device 2 412.00’ 6.0" Vert. Orifice C= 0.600 Limited to weir flow at low heads #4 ~=Device 2 414.00' 24.0" x 24.0" Horiz. Grate C= 0.600 Limited to weir flow at low heads jiscarded OutFlow Max=0.03 cfs @ 7.55 hrs HW=411.53' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=1.79 cfs @ 12.15 hrs HW=414.07' (Free Discharge) — ulvert (Passes 1.79 cfs of 5.52 cfs potential flow) Favorite (Orifice Controls 1.28 cfs @ 6.50 fps) =Grate (Weir Controls 0.51 cfs @ 0.88 fps) 44