Page 27 - planning-committee-packet

230550 HydroCAD
Concept HydroCAD-230550 Type II 24-hr 2-yr Rainfall=3.60"
Prepared by Lane Engineering, LLC Printed 5/26/2025
HydroCAD® 10.00-17 s/n 03788 © 2016 HydroCAD Software Solutions LLC Page 8

Summary for Pond 7P: P-2 SGW 2

Inflow Area = 0.927 ac, 53.39% Impervious, Inflow Depth > 2.54" for 2-yr event
Inflow = 3.23 cfs @ 11.98 hrs, Volume= 0.196 af
Outflow = 0.95 cfs @ 12.24 hrs, Volume= 0.134 af, Atten= 71%, Lag= 15.0 min
Primary = 0.95 cfs @ 12.24 hrs, Volume= 0.134 af
Secondary = 0.00 cfs @ 0.10 hrs, Volume= 0.000 af

Routing by Dyn-Stor-Ind method, Time Span= 0.10-24.01 hrs, dt= 0.03 hrs / 3
Peak Elev= 25.26' @ 12.24 hrs Surf.Area= 3,312 sf Storage= 4,170 cf

Plug-Flow detention time= 183.0 min calculated for 0.134 af (68% of inflow)
Center-of-Mass det. time= 85.5 min ( 887.2 - 801.7 )

Volume Invert Avail.Storage Storage Description
#1 23.85' 8,692 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)
23.85 2,618 200.0 0 0 2,618
26.50 3,990 239.0 8,692 8,692 4,099

Device Routing Invert Outlet Devices
#1 Primary 23.50' 15.0" Round 15" Culvert
L= 219.0' CPP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 23.50' / 23.00' S= 0.0023 '/' Cc= 0.900
n= 0.012, Flow Area= 1.23 sf
#2 Device 1 24.75' 0.9' long 0.9' notch 2 End Contraction(s)
#3 Device 1 25.85' 16.3' long WR Inlet 0 End Contraction(s)
#4 Secondary 25.90' 30.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
Primary OutFlow Max=0.95 cfs @ 12.24 hrs HW=25.26' TW=0.00' (Dynamic Tailwater)
1=15" Culvert (Passes 0.95 cfs of 4.09 cfs potential flow)
2=0.9' notch (Weir Controls 0.95 cfs @ 2.33 fps)
3=WR Inlet ( Controls 0.00 cfs)

Secondary OutFlow Max=0.00 cfs @ 0.10 hrs HW=23.85' TW=0.00' (Dynamic Tailwater)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)

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