The backing up of water in a stream due to dam construction is an example of
- ASteady rapidly varied flow
- BUnsteady spatially varied flow
- CSteady gradually varied flowCorrect
- DUnsteady gradually varied flow
Solution
Concept
Classification of flow in a channel behind a dam
Step-by-step solution
1. The depth varies slowly with distance upstream of the dam (backwater curve). 2. The discharge is constant with time. 3. So the flow is steady gradually varied flow.
Explanation
Backwater caused by a dam is a gradually varied flow profile (M1 curve). The discharge is constant with time, so it is steady flow. A hydraulic jump or a spillway would be rapidly varied flow.
Shortcut
Backwater / drawdown = steady gradually varied flow (GVF).
Common mistake
Choosing rapidly varied flow because a dam is involved.
Correct answer: C) Steady gradually varied flow