Question

Why the state of flow and the critical depth of a river or canal need to be determined?

Answer 1

Answer:

The flow of water will determine the extent of displacement of these particles. So, depending upon both these physical parameters, it can be ascertained how much will be the displacement & settlement of these various items. For settlements, depth of the river will say how much of these items have settled.

Answer 2

Explanation:

if we are sailing in a boat or ship this knowledge is important