Difference between revisions of "Natural rock catchment and Open water reservoir"
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- Cost is high – experience from Kenya shows that a 56 m3 dam cost $4,000 including labour (= $71 per m3 of storage) <br> | - Cost is high – experience from Kenya shows that a 56 m3 dam cost $4,000 including labour (= $71 per m3 of storage) <br> | ||
- Vectors can breed in open water<br> | - Vectors can breed in open water<br> | ||
− | - Microbiological and chemical water quality is likely to not be acceptable for direct consumption (see [[Natural ground catchment | + | - Microbiological and chemical water quality is likely to not be acceptable for direct consumption (see [[Natural ground catchment and Open water reservoir]]) |
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Revision as of 07:39, 5 April 2012
These are naturally occurring catchments of bare rock that have high runoff coefficients (around 0.9). Water can be stored as an open reservoir behind a retaining structure, with storage capacities ranging from 20 – 4,000 m3, or can be stored directly in a covered storage tank that collects water directly from the catchment.
Contents
Suitable conditions
- The rock that makes up the catchment should be bare and free of vegetation/soil. It should have no fractures or cracks that would result in a loss of water through seepage.
- Site the dams for rock catchments to maximize the natural topography – to get the best volume, make dams on the lower side of existing rock pools.
Advantages | Disadvantages/limitations |
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- High runoff coefficient = similar to roof catchments in that even small showers produce water - Minimal seepage |
- Not many sites suitable - If building tanks that store water directly, storage capacity is limited compared to an open reservoir |