Hydrologic Parameters
-
mm/hr
ha
Time of Concentration
min
IDF Storm Frequency Check
Calculating...
Analysis Results
Peak Discharge (Q)
--m³/s
Runoff Volume (V)
--m³
Est. Return Period
--yr
Reference Formulas
Rational Method:
SI: Q (m³/s) = C · I (mm/hr) · A (ha) / 360
US: Q (cfs) = C · I (in/hr) · A (ac)
Runoff Volume (Triangular Hydrograph):
V = (1/2) · Q · t_base
t_base = 2.5 · t_c (Standard TR-55 peaking factor)
IDF Reference: I = a / (t_c + b)^c (Typical regional coefficients applied)
Watershed Schematic
Triangular Hydrograph
Q vs I Sensitivity & IDF Envelope