An unlined irrigation canal in regime condition carries a design discharge of $Q = 45.0\text{ m}^3/\text{s}$. According to Lacey's regime theory, the wetted perimeter of the channel is ________ $\text{m}$ (round off to two decimal places).
Answer Key:
31.86
Step-by-Step Solution & Explanation
According to Lacey's regime formula, the wetted perimeter $P$ is solely a function of design discharge $Q$:
$P = 4.75 \sqrt{Q}$
Given $Q = 45.0\text{ m}^3/\text{s}$:
$P = 4.75 \times \sqrt{45.0} = 4.75 \times 6.7082 = 31.86\text{ m}$