Question

The term "Delta" used for irrigation practice can be expressed as.................
(A). cm
(B). cm/hr
(C). Poise
(D). Lux
Choose the correct answer from the options given below:

• (A) only
• (B) only
• (A) and (C) only
• (C) and (D) only

Hint:

Remember the classic relationship between Duty ($D$, in hectares/cumec), Delta ($\Delta$, in meters), and Base Period ($B$, in days):
\[ \Delta = \frac{8.64 \cdot B}{D} \]
This relationship helps calculate the total water depth needed for irrigation planning.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
In irrigation engineering, "Delta" ($\Delta$) represents the total depth of water required by a crop during its entire growing season from sowing to harvesting.
It is expressed as a cumulative depth of water over the cropped area.

Step 2: Detailed Explanation:
Let us analyze the dimensions and units of Delta:
Delta ($\Delta$) is a measure of cumulative water depth.
Therefore, its physical dimension is length ($L$).
Standard units for Delta are ______centimeters (cm)______, millimeters (mm), or meters (m).
Let us evaluate the other options:
- ______cm/hr (B):______ This represents a rate of water movement over time, which is the unit of infiltration rate or rainfall intensity, not cumulative depth.
- ______Poise (C):______ This is the CGS unit of dynamic viscosity, which has no relationship to irrigation depth.
- ______Lux (D):______ This is the SI unit of illuminance (light intensity), used in crop physiology, not irrigation.
Thus, only statement (A) is correct.

Step 3: Final Answer:
Delta is expressed in centimeters (cm), which corresponds to option (A).