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[[Image:leaky dams icon.png|right]]
[[Image:LeakyDam.jpg|thumb|right|350px200px|'''Leaky dam.''' Re-hydrating the earth by sustainable, small-scale sub-surface water retention techniques, Vietnam. Photo: Partners voor Water (2009).]]
A floodwater harvesting technique, these are permeable structures built across seasonal riverbeds which retain flash flood water that has a high silt load. The idea is to retain the high-energy floods and stimulate settlement of suspended sediment behind the dam. Water with a lower sediment load is then available to leak through the dam and infiltrate the downstream riverbed which is not blocked by sediment deposits. They have been proven to be able to recharge local aquifers. Leaky dams are excellent in semi-arid areas since they greatly reduce evaporation, in regards to storing water.
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! width="50%" style="background:#efefef;" | Advantages
! style="background:#ffdeadf0f8ff;" | Disadvantages
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| valign="top" | - Can assist recharge of shallow wells <br>
'''Specific advice''':
[[Image:LeakyDam2.jpg|thumb|right|350px200px|'''Leaky dam.''' Balochistan, Pakistan. Facing downstream. <br> Photo: [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDgQFjAB&url=http%3A%2F%2Funesdoc.unesco.org%2Fimages%2F0014%2F001438%2F143819e.pdf&ei=uqt8T9_sL6ibiQKTqdzFDQ&usg=AFQjCNFjJrN8OJHYuNSZrDZIrDtZxc_LRg&sig2=J7p3YnDub8Ixn2n4DU-uBw ''Strategies for Managed Aquifer Recharge (MAR) in semi-arid areas.''] UNESCO.]]
Similar construction as [[sand dam]]s:
* Construct wing walls to avoid erosion around edges.
==Manuals, videos, and links==
* [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDgQFjAB&url=http%3A%2F%2Funesdocunesdoc.unesco.org%2Fimages%2F0014%2F001438%2F143819e/images/0014/001438/143819e.pdf&ei=uqt8T9_sL6ibiQKTqdzFDQ&usg=AFQjCNFjJrN8OJHYuNSZrDZIrDtZxc_LRg&sig2=J7p3YnDub8Ixn2n4DU-uBw Strategies for Managed Aquifer Recharge (MAR) in semi-arid areas.] Excellent study of an arid area in Pakistan that used leaky dams.
==Acknowledgements==
* CARE Nederland, Desk Study: [[Resilient WASH systems in drought-prone areas]]. October 2010.
* Gale, Ian, [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDgQFjAB&url=http%3A%2F%2Funesdocunesdoc.unesco.org%2Fimages%2F0014%2F001438%2F143819e/images/0014/001438/143819e.pdf&ei=uqt8T9_sL6ibiQKTqdzFDQ&usg=AFQjCNFjJrN8OJHYuNSZrDZIrDtZxc_LRg&sig2=J7p3YnDub8Ixn2n4DU-uBw Strategies for Managed Aquifer Recharge (MAR) in semi-arid areas.] UNESCO's International Hydrological Programme (IHP), 2005.
