Question

A siphon aqueduct is constructed at a canal crossing site where drainage HFL was 212.2 m by allowing an afflux of 0.4 m at high flood discharge. At this site, the water level downstream of the crossing at the same high flood will be _________

(a) 212.2 m

(b) 212.6 m

(c) 211.8 m

(d) It cannot be predicted

I got this question in exam.

The origin of the question is Cross Drainage Work Design topic in division Cross Drainage Work of Irrigation Engineering

Answer 1

The correct choice is (a) 212.2 m

Explanation: The D/s HFL of the drain remains the same by the construction of works and the U/s HFL can be obtained by adding afflux to the D/s HFL.

The D/s water level = 212.2 m

The U/s water level = 212.2 + 0.4 = 212.6 m.