Question

A canal is used to irrigate 1000 hectares of land growing wheat of base 130days having a delta of 50 cm. If the same canal is used to irrigate rice of base period 160 days having a delta of 130 cm, the area than can be irrigated is:

• A. 312. 5 ha
• B. 473.4 ha
• C. 712.5 ha
• D. 1000 ha

Answer 1

The correct option is B 473.4 ha

For wheat

$B_1=130days,{\Delta }_1=50cm,A_1=1000hectares$

$Discharge,Q=\frac{A_1}{D_1}$

$=\frac{A_1{\Delta }_1}{8.64B_1}$

And for rice

$B_2=160days,{\Delta }_2=130cm,A_2=?$

$Q=\frac{A_2}{D_2}$

$\frac{A_1{\Delta }_1}{8.64B_1}=\frac{A_2{\Delta }_2}{8.64B_2}$

$A_2=\left(\frac{{\Delta }_1}{{\Delta }_2}\right)\left(\frac{B_2}{B_1}\right)A_1$

$=\left(\frac{50}{130}\right)\left(\frac{160}{130}\right)\times 1000$

$=473.37hectares$