An agricultural drainage basin of area $A = 170\text{ ha}$ is designed with a drainage coefficient of $DC = 3.5\text{ cm/day}$. The required design capacity of the main surface drainage ditch is ________ $\text{m}^3/\text{s}$ (round off to two decimal places).
Answer Key:
0.69
Step-by-Step Solution & Explanation
The drainage discharge is calculated as:
$Q = \frac{A \times DC}{864}$
where $A$ is in $\text{ha}$ and $DC$ is in $\text{cm/day}$, giving $Q$ in $\text{m}^3/\text{s}$:
$Q = \frac{170 \times 3.5}{864} = \frac{595.0}{864} = 0.689\text{ m}^3/\text{s}$
Rounding to two decimal places: $0.69\text{ m}^3/\text{s}$.