- 2080 Chaitra · 3 marks
Key differences between weir and barrage
Short answer
A weir has a raised crest with limited gate control, high afflux, low cost, and is suited for rocky rivers. A barrage has a low crest with many gates, better water level and silt control, small afflux, and higher cost, suited for alluvial plains with large discharge.
Discuss key differences between weir and barrage.
| Point | Weir | Barrage |
|---|---|---|
| Ponding | By raising the crest (solid, with shutters on top) | By gates; the crest is at low level |
| Control of water level | Limited; pond level is mostly fixed | Good; gates control the level and the flood passage |
| Gates | Few or none (shutters) | Many gates across the full width |
| Afflux in floods | Large | Small, because gates are opened |
| Cost | Low | High |
| Silt control | Poor | Better (scouring by gates) |
| Suitable for | Rocky or hilly rivers, small discharges | Alluvial plains, large rivers, high discharge |
| Foundation | Rock or sand, with piles | Usually sand; heavier floor and piles |
| Maintenance | Easy | More complex (gate machinery) |
✓ Answer checked by Claude Opus 5.5 (high effort)
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