Question

The sediment confined along and above the bed up to a depth ‘2d’ (d being grain size) is treated as bed load.

(a) True

(b) False

The question was posed to me during an interview.

This is a very interesting question from Sediment Transport in portion Sediment Transport and Irrigation Channels Design of Irrigation Engineering

Answer 1

Right answer is (a) True

Explanation: The sediment moves only on the top layers of the bed. Hence, the lower limit can be considered as equal to the thickness of the bed layer which is approximately equal to 2d and the upper limit as the total water depth. The sediment concentration at this depth can be considered equal to the concentration of bed load.