Question

What is the condition for digging of borrow pits?

(a) B/2 > b

(b) Depth of pit 7 < 1 m

(c) Should in the Centre

(d) Dig only External Pits

The question was asked in an online quiz.

Origin of the question is Cross-Section of an Irrigation Canal in chapter Sediment Transport and Irrigation Channels Design of Irrigation Engineering

Answer 1

The correct option is (a) B/2 > b

To explain I would say: For digging up of borrow pits the main condition is that the width of the pit (b) should be less than half the value of width of the canal (B/2). Other secondary conditions include that the pit should be dug in the centre, depth of the pit should be < 1 m, and it should start from a point at a distance of 5m from toe for small canals and 10 m for large canals.