Analysis - Proposed Conditions NOAA 24-hr D 10 YR-F Rainfall=6.34"
Prepared by Civil Core Consulting Printed 10/24/2025
HydroCAD® 10.20-7a s/n 13637 © 2025 HydroCAD Software Solutions LLC Page 276
Inflow Area = 1,850 sf,100.00% Impervious, Inflow Depth = 6.10" for 10 YR-F event
Inflow = 0.28 cfs @ 12.09 hrs, Volume= 941 cf
Outflow = 0.03 cfs @ 11.54 hrs, Volume= 941 cf, Atten= 88%, Lag= 0.0 min
Discarded = 0.03 cfs @ 11.54 hrs, Volume= 941 cf
Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs
Peak Elev= 91.90' @ 12.71 hrs Surf.Area= 0.013 ac Storage= 0.006 af
Plug-Flow detention time = 42.5 min calculated for 941 cf (100% of inflow) Center-of-Mass det. time = 42.5 min (782.9 - 740.4)
Volume Invert Avail.Storage Storage Description
#1A 91.00' 0.008 af 10.06'W x 57.33'L x 2.17'H Field A
#2A 91.33' 0.006 af 0.029 af Overall - 0.008 af Embedded = 0.020 af x 40.0% Voids
#2A 91.33' 0.006 af ADS N-12 15" x 12 Inside #1
Inside = 14.8"W x 14.8"H => 1.20 sf x 20.00"L = 24.0 cf
Outside = 18.0"W x 18.0"H => 1.60 sf x 20.00"L = 31.9 cf
Row Length Adjustment = -7.00' x 1.20 sf x 4 rows
8.72' Header x 1.20 sf x 2 = 20.9 cf Inside
0.014 af Total Available Storage
0.014 af Total Available Storage
Storage Group A created with Chamber Wizard
| Device | Routing | Invert | Outlet Devices |
|---|
| #1 | Discarded | 91.00' | 2.450 in/hr Exfiltration over Surface area |
| Discarded OutFlow | Max=0.03 cfs @ 11.54 hrs HW=91.02' (Free Discharge) |
| 1=Exfiltration (Exfiltration Controls 0.03 cfs) |
| Pond 37P: Subsurface Basin Lot 1 |
| Exfiltration |