240916_40 ERW Stormwater Report FULL

NOAA 24-hr D 2-Year Rainfall=3.44"240913_40 ERW Waymaker Proposed Printed 9/16/2024Prepared by Colliers Engineering & Design Page 62HydroCAD® 10.20-2g s/n 04431 © 2022 HydroCAD Software Solutions LLC Summary for Pond 11P: Existing Drywell System Inflow Area = 0.919 ac, 42.91% Impervious, Inflow Depth = 0.75" for 2-Year event Inflow = 0.74 cfs @ 12.06 hrs, Volume= 0.058 af Outflow = 0.20 cfs @ 12.27 hrs, Volume= 0.058 af, Atten= 73%, Lag= 12.5 min Discarded = 0.03 cfs @ 12.27 hrs, Volume= 0.039 af Primary = 0.17 cfs @ 12.27 hrs, Volume= 0.018 af Routed to Reach DP2 : CHANNEL Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 608.65' @ 12.27 hrs Surf.Area= 0.020 ac Storage= 0.019 af Plug-Flow detention time= 128.4 min calculated for 0.058 af (100% of inflow) Center-of-Mass det. time= 128.4 min ( 889.2 - 760.8 ) Volume Invert Avail.Storage Storage Description #1 606.75' 0.050 af 19.00'W x 46.00'L x 8.00'H Prismatoid 0.161 af Overall - 0.037 af Embedded = 0.124 af x 40.0% Voids #2 607.75' 0.037 af 6.00'D x 5.66'H Vertical Cone/Cylinder x 10 Inside #1 0.086 af Total Available Storage Device Routing Invert Outlet Devices #1 Discarded 606.75' 1.000 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 603.00' #2 Primary 608.00' 15.0" Round Culvert L= 16.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 608.00' / 607.75' S= 0.0156 '/' Cc= 0.900 n= 0.012 Corrugated PP, smooth interior, Flow Area= 1.23 sf #3 Device 2 608.00' 3.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Device 2 611.25' 4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #5 Device 2 613.25' 4.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Discarded OutFlow Max=0.03 cfs @ 12.27 hrs HW=608.65' (Free Discharge) 1=Exfiltration ( Controls 0.03 cfs) Primary OutFlow Max=0.17 cfs @ 12.27 hrs HW=608.65' (Free Discharge) 2=Culvert (Passes 0.17 cfs of 1.38 cfs potential flow) 3=Orifice/Grate (Orifice Controls 0.17 cfs @ 3.48 fps) 4=Orifice/Grate ( Controls 0.00 cfs) 5=Broad-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.