Question

Find the delta ($\Delta$) for a crop if the duty for a base period of 110 days is 1400 hectares/cumec.

• A. 0.68 m
• B. 0.08 m
• C. 0.86 m
• D. 0.98 m

Hint:

If you need Delta in centimeters, the formula becomes $\Delta = \frac{864B}{D}$. High Duty means more land is irrigated with the same amount of water, which results in a lower Delta (water depth).

Answer 1

The Correct Option is A

Concept: In irrigation engineering, Delta ($\Delta$), Duty ($D$), and Base Period ($B$) are related. Delta is the total depth of water required by a crop during its base period.

Step 1: Identify the relationship formula.
The standard formula relating these three parameters is: \[ \Delta = \frac{8.64 \times B}{D} \] Where:
• $\Delta = \text{Delta in meters (m)}$
• $B = \text{Base period in days} = 110 \text{ days}$
• $D = \text{Duty in hectares/cumec} = 1400 \text{ ha/cumec}$

Step 2: Perform the calculation.
\[ \Delta = \frac{8.64 \times 110}{1400} \] \[ \Delta = \frac{950.4}{1400} \] \[ \Delta \approx 0.6788 \text{ m} \] Rounding to two decimal places, we get $0.68 \text{ m}$.