Question

The most desirable alignment of an irrigation canal is along

• A. The contour line
• B. The ridge line
• C. Normal to contour line
• D. The valley line

Answer 1

The correct option is B The ridge line

Irrigation water in flow type that should reach the fields by gravity.
To accomplish this requirement irrigation canal is always aligned along a ridge line or watershed line.
(i) The watershed or ridge line is a dividing line between two drainage areas. Thus a canal which runs over the ridge command of area on both sides of ridge
(ii) Another advantage of keeping a canal along ridge is that crossing of drains and canal are completely avoided. Thus minimum cross drainage work.