Question

The duty of water is defined as:

• A. Volume of water applied per unit area
• B. Area irrigated by unit discharge flowing continuously during crop period
• C. Depth of water applied to the field
• D. Rate of evapotranspiration

Hint:

Duty and delta are inversely related — higher duty means less depth of water required.

Answer 1

The Correct Option is B

Step 1: Understanding duty of water.
The duty of water is an important concept in irrigation engineering. It helps in determining how efficiently water is used for irrigation purposes over a specific period.
Step 2: Defining unit discharge.
Unit discharge refers to a fixed quantity of water flowing continuously, usually expressed as one cubic meter per second (cumec).
Step 3: Relation between duty and irrigated area.
Duty of water is defined as the total area that can be irrigated by one unit of discharge flowing continuously during the entire crop growth period.
Step 4: Analyzing the options.
(A) Volume of water applied per unit area: This describes irrigation requirement, not duty.
(B) Area irrigated by unit discharge flowing continuously during crop period: Correct — this is the standard definition of duty of water.
(C) Depth of water applied to the field: This refers to delta of water, not duty.
(D) Rate of evapotranspiration: This is a climatic parameter, not related to duty.
Step 5: Conclusion.
The duty of water is correctly defined as the area irrigated by unit discharge flowing continuously during the crop period.