The type of diversion headwork in which a major part or the entire ponding of water is achieved by a raised crest and a smaller part or nil part of it is achieved by the shutters is known as
- AWeirCorrect
- BBarrage
- CAqueduct
- DCanal escape
Solution
Concept
Difference between weir and barrage
Step-by-step solution
1. Weir: ponding is mainly by a raised crest; gates (shutters) on top are small or absent. 2. Barrage: ponding is mainly by gates; the crest is kept low and the raised portion is small. 3. The type described (major or whole ponding by a raised crest, small or nil by shutters) is a weir.
Explanation
A weir holds the water level mostly by the raised crest of the structure. A barrage is a weir with a low crest and a large number of gates that control the water level. An aqueduct is a cross-drainage work and a canal escape is a safety outlet from a canal.
Shortcut
Weir = crest does the work; Barrage = gates do the work.
Common mistake
Marking barrage because it also diverts water.
Correct answer: A) Weir