Question

By how many considerations the depth downstream vertical cutoff is governed?

(a) 2

(b) 1

(c) 3

(d) 4

The question was posed to me in final exam.

My question is based upon Seepage Theories topic in chapter Seepage Theories and Weirs and Barrages Design of Irrigation Engineering

Answer 1

The correct answer is (a) 2

To elaborate: In order to prevent undermining, it is absolutely necessary to provide a reasonably deep vertical cutoff at the downstream end of the downstream pucca floor. The depth of this downstream vertical cutoff is governed by two considerations, namely maximum depth of scour and safe exit gradient.