Analysis - Failure NOAA 24-hr D 2 YR-C Rainfall=3.42" Prepared by Civil Core Consulting Printed 12/19/2025 HydroCAD® 10.20-8a s/n 13637 © 2025 HydroCAD Software Solutions LLC Page 22
Summary for Subcatchment 8S: DA-P1 IMPERVIOUS
Runoff = 1.33 cfs @ 12.11 hrs, Volume= Routed to Pond 5P : BIORETENTION BASIN 1A
4,627 cf, Depth= 3.19"
Runoff by SCS TR-20 method, UH=Delmarva, Split Pervious/Imperv. UI as Pervious, Time Span= 0.00-72.00 hrs, dt= NOAA 24-hr D 2 YR-C Rainfall=3.42"
Area (ac) CN Description
0.400 98 Paved roads w/curbs & sewers, HSG A
0.400 98 100.00% Impervious Area
Tc (min) Length (feet) Slope (ft/ft) Velocity (ft/sec) Capacity (cfs) Description
1.4 235 0.0200 2.87 Shallow Concentrated Flow, Paved Kv= 20.3 fps
1.1 137 2.00 Direct Entry, Pipe Flow
2.5 372 Total
Subcatchment 8S: DA-P1_IMPERVIOUS
Subcatchment 8S: DA-P1 IMPERVIOUS
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours)