Gully Control and Drop Spillways

In a drop inlet pipe spillway, the pipe barrel has diameter $D = 0.5\text{ m}$ (area $A = \frac{\pi}{4}(0.5)^2 \approx 0.1963\text{ m}^2$). When flowing full under total head $H = 4.0\text{ m}$ with overall discharge coefficient $C_d = 0.65$, taking $g = 9.81\text{ m/s}^2$ the pipe discharge in $\text{m}^3/\text{s}$ is (rounded off to two decimal places):