Question

Which of the following statement is wrong?

(a) Threshold condition is the one in which a few particles on the bed will just start moving

(b) Knowledge of critical velocity helps in designing stable non-scouring channels

(c) The critical tractive force approach helps in designing unstable channels in alluviums

(d) The knowledge of threshold condition is required for the computation of sediment load

This question was addressed to me in class test.

This key question is from Sediment Transport topic in portion Sediment Transport and Irrigation Channels Design of Irrigation Engineering

Answer 1

The correct choice is (c) The critical tractive force approach helps in designing unstable channels in alluviums

To elaborate: Shield was the first person to analyze the experimental data on incipient motion condition using the critical tractive force approach. The assumption of the entry of clean and clear water in the channel is used to develop non-scouring highest possible flow velocity at the peak flow.