Question

Wheat crop requires 55 cm of water during 120 days of base period. The total rainfall during this period is 100 mm. Assume the irrigation efficiency to be 60%. The area (in ha) of the land which can be irrigated with a canal flow of 0.01 m3/s is
1. 13.82
2. 18.85
3. 23.04
4. 230.04
5.

Answer 1

Correct Answer - Option 1 : 13.82

Explanation:

Given:

Rainfall = 100 mm = 10 cm, Base period of rice = 120 days

water requirement by rice = 55 cm, irrigation efficiency = 60 %

Canal flow = 0.01 m3/sec

Now, the actual requirement of water through the canal for irrigation is

Δ = 55 cm – 10 cm = 45 cm = 0.45 m

we know that,

\(\Delta = 8.64\frac{B}{D}\)

Where, Δ = Delta of the crop in m

D = Duty, in hectares /cumec, B = Base period in days

\(\therefore D = \frac{{8.64 \;\times\; 120}}{{0.45}}\)

D = 2304 hectare/cumec

∴ Area of land that can be irrigated with 0.01 m3/s is = 2304 × 0.01

= 23.04 hectares

Since the irrigation efficiency is 60% then the area of land that can be irrigated for rice crop is

\(= 23.04 \times \frac{{60}}{{100}}\)

= 13.824 hectares