102 Sams -REV 12-02-25 NOAA 24-hr D 2-Year Rainfall=3.42" Prepared by Haler Consulting Printed 04/12/2025 HydroCAD® 10.20-2h s/n 10351 © 2024 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment 170S: DA P1 (Impervious)
Runoff = 2.34 cfs @ 12.11 hrs, Volume= 8,398 cf, Depth= 3.19" Routed to Pond 183P : WQ Infiltration Basin #1
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-Year Rainfall=3.42"
Area (sf) CN Description
31,625 98 Paved parking, HSG A
31,625 98 100.00% Impervious Area
Tc (min) Length (feet) Slope (ft/ft) Velocity (ft/sec) Capacity (cfs)
1.2 100 0.0200 1.42 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.42"
1.8 350 0.0250 3.21 Shallow Concentrated Flow, Paved Kv= 20.3 fps
3.0 450 Total
Subcatchment 170S: DA P1 (Impervious)