Page 43 - planning-committee-packet

230550 HydroCAD
Concept HydroCAD-230550 Type II 24-hr 100-yr Rainfall=8.10"
Prepared by Lane Engineering, LLC Printed 5/26/2025
HydroCAD® 10.00-17 s/n 03788 © 2016 HydroCAD Software Solutions LLC Page 24

Summary for Pond 5P: P-1 SGW 1

Inflow Area = 0.909 ac, 55.27% Impervious, Inflow Depth > 6.89" for 100-yr event
Inflow = 8.15 cfs @ 11.98 hrs, Volume= 0.522 af
Outflow = 6.87 cfs @ 12.05 hrs, Volume= 0.388 af, Atten= 16%, Lag= 4.0 min
Primary = 3.44 cfs @ 12.05 hrs, Volume= 0.334 af
Secondary = 3.44 cfs @ 12.05 hrs, Volume= 0.054 af

Routing by Dyn-Stor-Ind method, Time Span= 0.10-24.01 hrs, dt= 0.03 hrs / 3
Peak Elev= 24.49' @ 12.05 hrs Surf.Area= 7,159 sf Storage= 9,871 cf

Plug-Flow detention time= 196.7 min calculated for 0.388 af (74% of inflow)
Center-of-Mass det. time= 108.9 min ( 883.6 - 774.6 )

Volume Invert Avail.Storage Storage Description
#1 23.00' 13,638 cf Custom Stage Data (Irregular) Listed below (Recalc)

Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
23.00 6,129 338.0 0 0 6,129
25.00 7,533 364.0 13,638 13,638 7,742

Device Routing Invert Outlet Devices
#1 Primary 22.50' 15.0" Round 15" Culvert
L= 50.0' CPP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 22.50' / 22.00' S= 0.0100 '/' Cc= 0.900
n= 0.012, Flow Area= 1.23 sf
#2 Device 1 23.75' 0.5' long 6" notch 2 End Contraction(s)
#3 Device 1 24.35' 16.3' long WR Inlet 0 End Contraction(s)
#4 Secondary 24.38' 30.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
Primary OutFlow Max=3.36 cfs @ 12.05 hrs HW=24.48' TW=0.00' (Dynamic Tailwater)
1=15" Culvert (Passes 3.36 cfs of 6.89 cfs potential flow)
2=6" notch (Weir Controls 0.73 cfs @ 2.80 fps)
3=WR Inlet (Weir Controls 2.63 cfs @ 1.20 fps)

Secondary OutFlow Max=3.32 cfs @ 12.05 hrs HW=24.48' TW=0.00' (Dynamic Tailwater)
4=Sharp-Crested Rectangular Weir (Weir Controls 3.32 cfs @ 1.06 fps)

8.13.25 PC Meeting Packet_pg. 41 of 78