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Broad Crested Weir refers to the flow measurement and regulation of water depth in rivers, canals and other natural open channels. Broad Crested Weirs are a robust structure used to measure the full width of the channel. A broad crested weir is normally a flat topped object which obstructs and extends across the entire channel.

Broad Crested Weir Calculator

Table of Contents:

**Formula**

**q = C _{d} × b × h_{2} × (2g (h_{1} - h_{2})) ^{1/2}**

**Where,**

q = Water Flow Rate

C_{d} = Discharge Constant

b = Width of the Weir

g = Gravity (9.81 m/s^{2})

h_{1}, h_{2} = Head 1 and Head 2 on the Weir

An overflow structure on which the nappe is supported for an appreciable length in the direction of flow is called as broad crested weir. It is a flat-crested structure, with a long crest compared to the flow thickness of water in canals and rivers.

__Example__:

Calculate the Broad Crested Weir for the given details.

Width of the Weir (b) = 5 m

Head 1 on the Weir (h_{1}) = 3 m

Head 2 on the Weir (h_{2}) = 1 m

Discharge Constant (C_{d}) = 10

__Solution__:

**Apply Formula:**

q = C_{d} × b × h_{2} × (2g (h_{1} - h_{2})) ^{1/2}

**Water Flow Rate (q) = 313.20919526731655 m ^{3}/s**