Question

What type of force is completely responsible for the bedload movement?

(a) Forces of Turbulence

(b) Drag Force

(c) Capillary Force

(d) Gravity Force

This question was addressed to me in exam.

My doubt stems from Sediment Transport in chapter Sediment Transport and Irrigation Channels Design of Irrigation Engineering

Answer 1

The correct answer is (b) Drag Force

To elaborate: Generally we know that bedload is a type of sediment which moves adjacent to the bed of the channel. Shear stress (τo) is responsible for this movement of bedload along the bed if the channel, which is developed by the flowing water along the channel bed. This shear force is called drag force or tractive force.