Question

Water course commands an irrigated area of 1000 hectares. The intensity of irrigation of rice in this area is 60%. The transplantation of rice takes 15 days and during the transplantation period, the total depth of water required by the crop on the field is 800 mm. During the transplantation, the rainfall on the field is expected to be of order of 150 mm. If the losses of water are assumed to be 20% in the water course, the discharge required at the head of water course is :

• A. 3.08 cumecs
• B. 3.42 cumecs
• C. 3.60 cumecs
• D. 3.76 cumes

Answer 1

The correct option is D 3.76 cumes

Depth of water required from water course = 800-150=650 mm

Rice area = 0.6 x 1000 = 600 ha

Transplantation period = 15 days

$\text{Duty of irrigation water =}\frac{864\times 15}{65}=199.4$

$=\frac{864\times 15}{65}=199.4ha/cumecs$

Duty at the head of water course = 199.4 x 0.8 = 159.5 ha/cumecs

$\therefore$ discharge required at the head of water course

$=\frac{600}{159.5}=3.76cumecs$