Manning's Flow Calculator

Calculate Manning's Flow Rate







Formula

To calculate the Manning's Flow Rate (\(Q\)):

\[ Q = \frac{1.49}{n} \cdot A \cdot R^{\frac{2}{3}} \cdot \sqrt{s} \]

Where:

What is Manning's Flow?

Manning's flow is a metric of the volumetric flow rate of water moving through an open channel. The volumetric flow rate is calculated using Manning's Equation, which is stated above. The equation itself was developed as an alternative to the Chezy Equation for flow through channels to try and achieve more accurate calculations.

Example Calculation

Let's assume the following values:

Using the formula:

\[ Q = \frac{1.49}{0.03} \cdot 20 \cdot 2^{\frac{2}{3}} \cdot \sqrt{0.01} \approx 157.68 \text{ ft}^3/\text{s} \]

The Manning's Flow Rate is approximately 157.68 ft3/s.