Difference between revisions of "Water Portal / Rainwater Harvesting / Groundwater recharge / Check dams (gully plugs)"
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==Costs== | ==Costs== | ||
| − | + | The cost in India is reported to be between US$200-400 for temporary dams (made from brush wood, rocks, soil) and US$1,000- | |
| − | 3,000 for permanent dams (made from stones, bricks, cement). Variation depends on materials used and size of gully. | + | 3,000 for permanent dams (made from stones, bricks, cement), depending on the length and height. Variation depends on materials used and size of gully. |
Revision as of 01:38, 2 April 2012
A check dam is a small, temporary or permanent dam constructed across a drainage ditch, gully, swale, or channel to lower the speed of concentrated flows (like an overflow weir) for a certain design range of storm events. They may be more categorized as a type of floodwater rather than a runoff harvesting technique. A check dam can be built from logs of wood, stone, pea gravel-filled sandbags or bricks and cement. They have been used widely in Kenya and India. These dams can also be made as leaky dams. Sand dams that have been built in riverbeds with no coarse sand transport may end up being used in this way.
Suitable conditions
- Locate in natural runoff areas
- Soil in vicinity needs to have sufficient infiltration capacity.
| Advantages | Disadvantages/limitations |
|---|---|
| - Water speed is slowed, which reduces erosion and prevents unwanted gully formation during a flood - No trench design required, just uses existing gully drainage pattern |
- If designed incorrectly, may block fish passage - They can silt up and will need maintenance |
Construction, operations and maintenance
These can be made of temporary or permanent materials in natural gullies in the land surface. Materials used are concrete, earth, vegetation, stone and brushwood. Where earth is used, erosion or destruction of the structure needs to be avoided – to do this, a concrete spillway is often constructed. As they use the existing drainage system, no design of trench is needed as with contour trenches.
Costs
The cost in India is reported to be between US$200-400 for temporary dams (made from brush wood, rocks, soil) and US$1,000- 3,000 for permanent dams (made from stones, bricks, cement), depending on the length and height. Variation depends on materials used and size of gully.
