Unit Hydrograph Calculator
Calculate the SCS triangular unit hydrograph peak flow, time to peak, and time base from drainage area, lag time, and storm duration.
Inputs
km²
hrs
hrs
Results
Peak Discharge (Qp)
29.71 m³/s/mm
Time to Peak (Tp)
3.5 hrs
Time Base (Tb)9.34 hrs
Time of Concentration5.01 hrs
Recession Time5.84 hrs
Unit Volume499,824 m³
Expected Volume (1mm)50,000 m³
How to Use This Calculator
- Enter Drainage Area, Basin Lag Time, and Unit Rainfall Duration.
- Review Peak Discharge (Qp) (m³/s/mm) and Time to Peak (Tp) (hrs).
- Use Time Base (Tb) (hrs) and Time of Concentration (hrs) to inform your decision.
- Use the chart to visualize the results and explore different scenarios by adjusting inputs.
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Formula
Tp = D/2 + Tlag; Qp = 2.08 × A / TpRelated Calculators
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