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Supporting Documentation · Jan 22, 2025

240916_40 ERW Stormwater Report FULL

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NOAA 24-hr D 2-Year Rainfall=3.44"240913_40 ERW Waymaker Proposed Printed 9/16/2024Prepared by Colliers Engineering & Design Page 66HydroCAD® 10.20-2g s/n 04431 © 2022 HydroCAD Software Solutions LLC Summary for Pond 12P: Subsurface Infiltration Basin Inflow Area = 0.687 ac, 28.51% Impervious, Inflow Depth = 1.77" for 2-Year event Inflow = 1.06 cfs @ 12.08 hrs, Volume= 0.101 af Outflow = 0.10 cfs @ 13.57 hrs, Volume= 0.101 af, Atten= 91%, Lag= 89.4 min Discarded = 0.09 cfs @ 13.57 hrs, Volume= 0.100 af Primary = 0.01 cfs @ 13.57 hrs, Volume= 0.001 af Routed to Pond 11P : Existing Drywell System Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 622.57' @ 13.57 hrs Surf.Area= 0.061 ac Storage= 0.041 af Plug-Flow detention time= 188.2 min calculated for 0.101 af (100% of inflow) Center-of-Mass det. time= 188.1 min ( 998.9 - 810.8 ) Volume Invert Avail.Storage Storage Description #1A 621.50' 0.056 af 39.50'W x 67.70'L x 3.50'H Field A 0.215 af Overall - 0.076 af Embedded = 0.139 af x 40.0% Voids #2A 622.00' 0.076 af ADS_StormTech SC-740 +Cap x 72 Inside #1 Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap 72 Chambers in 8 Rows 0.132 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 621.50' 1.000 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 619.00' #2 Primary 619.43' 12.0" Round Culvert L= 42.0' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 619.43' / 613.00' S= 0.1531 '/' Cc= 0.900 n= 0.012 Corrugated PP, smooth interior, Flow Area= 0.79 sf #3 Device 2 622.50' 2.5" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Device 2 623.25' 10.0" W x 4.0" H Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #5 Device 2 624.50' 0.5' long Sharp-Crested Rectangular Weir 2 End Contraction(s) Discarded OutFlow Max=0.09 cfs @ 13.57 hrs HW=622.57' (Free Discharge) 1=Exfiltration ( Controls 0.09 cfs) Primary OutFlow Max=0.01 cfs @ 13.57 hrs HW=622.57' (Free Discharge) 2=Culvert (Passes 0.01 cfs of 5.42 cfs potential flow) 3=Orifice/Grate (Orifice Controls 0.01 cfs @ 0.92 fps) 4=Orifice/Grate ( Controls 0.00 cfs) 5=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) This document was created by an application that isn’t licensed to use

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(Orifice Controls 0.01 cfs @ 0.92 fps) 4=Orifice/Grate ( Controls 0.00 cfs) 5=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) This document was created by an application that isn’t licensed to use novaPDF. Purchase a license to generate PDF files without this notice.

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