Rational Method Peak Discharge Calculator

Storm-water Discharge by Rational Method

The Rational method is very popular to calculate peak discharge for its simplicity

to use. Thomas Mulvany invented this method and it was first used in 1851 in

Ireland according to the documented history. According to this method,

Considering a rainfall of uniform intensity and long duration

occurring over a basin.

Qp = CIA for t≥ tc

tc = The time taken for a drop of water from the farthest part

of the catchment to reach the outlet

Qp = Peak Runoff

C = Coefficient of runoff

I = Intensity of rainfall

A = Area of the catchment

Here, I built an online free calculator to calculate the peak discharge by this

well-known Rational Method.

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