2026-02 Existing and Proposed Prepared by Dynamic Engineering HydroCAD\circledR 10.20-8a s/n 08640 © 2025 HydroCAD Software Solutions LLC NOAA 24-hr D 10-Year-Current Rainfall=5.38" Printed 2/10/2026 Page 51
Link 18L: Study Area Road Undetained (Total) Inflow=0.10 cfs 0.015 af Primary=0.10 cfs 0.015 af
Total Runoff Area = 2.340 ac Runoff Volume = 0.408 af Average Runoff Depth = 2.09" 62.82% Pervious = 1.470 ac 37.18% Impervious = 0.870 ac
| 2026-02 Existing and Proposed | NOAA 24-hr D 10-Year-Current Rainfall=5.38" |
|---|
| Prepared by Dynamic Engineering | Printed 2/10/2026 |
| HydroCAD ® 10.20-8a s/n 08640 © 2025 HydroCAD Software Solutions LLC | Page 52 |
Runoff = 0.05 cfs @ 12.93 hrs, Volume= 0.022 af, Depth= 0.28"
Routed to Link 5L : Ex Study Area West (Total)
Runoff by SCS TR-20 method, UH=Delmarva, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 10-Year-Current Rainfall=5.38"
Area (ac) CN Description
0.930 39 >75% Grass cover, Good, HSG A
0.930 39 100.00% Pervious Area
Tc (min) Length (feet) Slope (ft/ft) Velocity (ft/sec) Capacity (cfs) Description
8.4 47 0.0350 0.09 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 4.04" Using McCuen-Spiess flow length
0.4 51 0.0200 2.28 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps
8.8 98 Total, Increased to minimum Tc= 10.0 min
Subcatchment 3S: Ex. Study Area West (Perv)