Question

What will be the head discharge of a canal required for the crops listed below. The time factor may be assumed as 0.75.

Crop	Base period	Area(ha)	Duty(ha/ cumecs)
Rice	120	4000	1200
Wheat	120	5000	1800
Sugarcane	310	3000	1200

• A. 8.61 cumecs
• B. 6.41cumecs
• C. 7.77 cumecs
• D. 11.48 cumecs
  

Answer 1

The correct option is C 7.77 cumecs

Discharge required:

$\text{For Rice}=\frac{4000}{1200}=3.33cumecs\left(Q_1\right)$

$\text{For Wheat}=\frac{5000}{1800}=2.78cumecs\left(Q_2\right)$

$\text{For Sugarcane}=\frac{3000}{1200}=2.5cumecs\left(Q_3\right)$

As base period of sugarcane is 310 days, it will require water in both crop seasons i.e., Rabi and Kharif.

Hence, discharge required

$=max(Q_1+Q_3,Q_2+Q_3)$

$=max(3.33+2.5,2.78+2.5)$

$=3.33+2.5=5.83cumecs$

Head discharge of canal required

$=\frac{5.83}{0.75}=7.77cumecs$