Question

The GCA of an irrigation project is 1,00,000 hectares. The culturable command area is 70% of GCA, the intensity of irrigation for kharif and Rabi are 50% and 60% respectively. The duties of kharif and Rabi are 1200 ha/cumecs and 1600 ha/cumecs respectively. What will be the discharge at the head of the canal considering 20% transmission losses?

• A. 29 cumecs
• B. 31.2 cumecs
• C. 35 cumecs
• D. 36.5 cumecs

Answer 1

The correct option is D 36.5 cumecs

$\text{Area under kharif}=\text{CCA}\times \text{Intensity of irrigation}$

$=(0.70\times 100000)\times 0.50=35000ha$

$\text{And area under Rabi}=(0.70\times 100000)\times 0.60=42000ha$

Discharge Required,
$\to \text{For Kharif}=\frac{35000}{1200}=29.17cumecs$

$\to \text{For Rabi}=\frac{42000}{1600}=26.25cumecs$

$\Rightarrow \text{Discharge at the head of field = max.}(29.17,26.25)=29.17cumecs$

$\because \text{20\% of water is lost in conveyance,}$

Hence, discharge required at the head of canal

$=\frac{29.17}{0.8}=36.46cumecs$