2026-02 Existing and Proposed NOAA 24-hr D 2-Year-Projected Rainfall=4.04" Prepared by Dynamic Engineering Printed 2/10/2026 HydroCAD® 10.20-8a s/n 08640 © 2025 HydroCAD Software Solutions LLC Page 39
Summary for Subcatchment 15S: Study Area Roof (Imp)
Runoff = 0.28 cfs @ 12.19 hrs, Volume= 0.035 af, Depth= 3.81" Routed to Link 16L : Study Area Basin A (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 2-Year-Projected Rainfall=4.04"
Area (ac) CN Description
0.110 98 Roofs, HSG A
0.110 98 100.00% Impervious Area
Tc (min) Length (feet) Slope (ft/ft) Velocity (ft/sec) Capacity (cfs)
0.8 207 0.0100 4.50 1.57 Pipe Channel, A-B 8.0" Round Area= 0.3 sf Perim= 2.1' r= 0.17' n= 0.010 PVC, smooth interior
0.8 207 Total, Increased to minimum Tc = 10.0 min
Subcatchment 15S: Study Area Roof (Imp)
2026-02 Existing and Proposed NOAA 24-hr D 2-Year-Projected Rainfall=4.04"
Prepared by Dynamic Engineering Printed 2/10/2026
HydroCAD\circledR 10.20-8a s/n 08640 © 2025 HydroCAD Software Solutions LLC Page 40
Summary for Subcatchment 19S: Study Area Road Undetained (Perv)
Runoff = 0.00 cfs @ 17.02 hrs, Volume= 0.000 af, Depth= 0.05"
Routed to Link 18L : Study Area Road Undetained (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 2-Year-Projected Rainfall=4.04"
Area (ac)CNDescription
0.09039>75% Grass cover, Good, HSG A
0.09039100.00% Pervious Area
Tc (min)Length (feet)Slope (ft/ft) Velocity (ft/sec) Capacity (cfs)
4.8580.0300 0.20
Sheet Flow, A-B
Grass: Short n= 0.150 P2= 4.04"
4.8 58 Total, Increased to minimum Tc = 10.0 min
Subcatchment 19S: Study Area Road Undetained (Perv)