Storm Drain Sizing Calculator
Inputs
ASCE: roofs/pavement 0.85–0.95; lawns (flat) 0.10–0.35; cultivated land 0.30–0.50
in/hr
acres
ft/ft
Tab to move between fields
Results
Design Flow (Q)
10 cfs
Selected Pipe Size
18 in
Required Diameter17.7 in
Flow Velocity5.94 ft/s
Pipe Capacity10.5 cfs