Question

A part of tractive force does not have any part in transporting the bed material, i. e bed load.

(a) True

(b) False

This question was posed to me in a job interview.

My query is from Sediment Transport in section Sediment Transport and Irrigation Channels Design of Irrigation Engineering

Answer 1

The correct answer is (a) True

Best explanation: In order to transport the bed load the tractive force (τo) should exceed the critical tractive force (τc), therefore the rate of movement of bedload becomes a function of (τo – τc). But, as soon as the sediment starts moving it is opposed by the ripples generated by the channel bed, and to overcome these ripples a large part of tractive force is lost and cannot be used again. So, this part of the force does not have any part in transporting the bed load.