## Burkli Ziegler Formula

Burkli Ziegler formula is the oldest formula used to determine the peak runoff rate. It was derived by a swiss engineer for local conditions. After that, it was followed in the whole U.S.A.

In M.K.S unites it states that

[latex] Q_{p} = \left ( \frac{1}{455} \right )\, K^{‘}\, .\, p\, .\, A\, .\, \sqrt{\frac{S_{0}}{A}} [/latex]

Where,

► [latex] Q_{p} [/latex] = The peak runoff in cumecs.

► [latex] K^{‘} [/latex] = Runoff coefficient (Depending upon the permeability of the surface), and the average value is taken as 0.7.

► p = The maximum rainfall intensity over the entire area( Usually the value is taken as 2.5 to 7.5 cm/hr.

► A = Drainage area in hectares.

► S_{0} = The slope of the ground surface in meters per thousand meters.

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