A crop requires a total irrigation depth of $\Delta = 60\text{ cm}$ over a base period of $B = 120\text{ days}$. The duty of water at the field channel head ($D = \frac{8.64 B}{\Delta}$ in $\text{ha/cumec}$) is ________ (answer in integer).
Answer Key:
1728
Step-by-Step Solution & Explanation
The relation between duty $D$, delta $\Delta$, and base period $B$ is:
$D = \frac{8.64 B}{\Delta}$
Where:
• $B = 120\text{ days}$
• $\Delta = 60\text{ cm} = 0.60\text{ m}$
$D = \frac{8.64 \times 120}{0.60} = 8.64 \times 200 = 1728\text{ ha/cumec}$