# Weir Flow Calculator

## About Weir Flow Calculator (Formula)

The Weir Flow Calculator is a tool used to estimate the flow rate of water over a rectangular weir. A weir is a structure built across an open channel to measure or control the flow of water.

The formula used to calculate the flow rate of a rectangular weir is:

Q = 3.247 * L * H^1.48 – [(.566 * L^1.9) / (1 + 2 * L^1.87)] * H^1.9

In this formula, Q represents the flow rate in cubic feet per second (ft³/s), L is the width of the channel at the base of the weir in feet, and H is the height of the upstream water above the weir crest in feet.

To use the Weir Flow Calculator, you need to input the values for the width of the channel (L) and the height of the upstream water (H). The calculator then applies the formula to calculate the flow rate (Q).

The resulting flow rate represents an estimate of the volume of water passing through the weir per unit of time. It is important to note that this formula is specific to rectangular weirs and may not be accurate for other types of weirs or flow conditions.

The Weir Flow Calculator is commonly used in hydrology, civil engineering, and environmental studies to assess and predict water flow rates in open channels. It provides valuable information for designing and managing water control structures, monitoring water resources, and analyzing hydraulic systems.