Water Measurement Flumes

In an open channel of rectangular section with bottom width $b = 3.0\text{ m}$ and depth $y = 1.5\text{ m}$, average velocity determined by current meter is $\bar{v} = 0.8\text{ m/s}$. Flow discharge $Q = A \bar{v} = (3.0 \times 1.5) \times 0.8$ in $\text{m}^3/\text{s}$ is: