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[[Image:check dams (gully plugs) icon.png|right|80px]]
[[Image:check dam india.jpg|thumb|right|200px|Check Dam for Rainwater Conservation. NMDC Diamond Mine, Panna, Madhya Pradesh. Photo: [http://greenfieldeco.com/photogallery.php Greenfield Eco Solutions Pvt. Ltd.]]]
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]]. Dams that have been built in riverbeds with no coarse sand transport ([[Sand dam]]s) may end up being used in this way. These structures are relatively cheap and can last about 2-5 years.
===Suitable conditions===
* Locate in natural runoff areas
* Soil in vicinity needs to have sufficient infiltration capacity.
===Resilience to changes in the environment===
[[Image:EthiopianGullyPlug.jpg|thumb|right|200px|Rehabilitated gully in Adaga Lemne watershed, Axum, Tigray Province. Photo: Johan Rockstrom.]]
====Drought====
With intense rain events, see if the check dam is still managing flow from its center. If it is not, the dam could crumble, rendering it ineffective, and will need rebuilding.
===Construction, operations and maintenance===
'''General advice on cement''': A common cause of cracks in structures and linings (e.g. in tanks, dams, waterways, wells) is errors in mixing and applying the cement. First of all, it is important that only pure ingredients are used: clean water, clean sand, clean rocks. The materials have to be mixed very thoroughly. Secondly, the amount of water during mixing needs to minimal: the concrete or cement needs to be just workable, on the dry side even, and not fluid. Thirdly, it is essential that during curing the cement or concrete is kept moist at all times, for at least a week. Structures should be covered with plastic, large leaves or other materials during the curing period, and kept wet regularly.
Check dams should be inspected regularly for sediment accumulation after each significant rainfall. Sediment should be removed when it reaches one-half of the original height or before. Check to ensure that the flow is over the centre of the dam and not either under or around the dam. Check that there is no erosion at the outfall.
===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.
===Field experiences===In Ethiopia, unclarity over land tenure led to progressive abandonment of cropping in gullies. See: Falkenmark, M.; Fox, P.; Persson, G.; Rockström, J. (2001) [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CD0QFjAA&url=http%3A%2F%2Fwww.siwi.org%2Fdocuments%2FResources%2FReports%2FReport11_Water_Harvesting_for_Upgrading_Rainfed_Agriculture_2001/documents/Resources/Reports/Report11_Water_Harvesting_for_Upgrading_Rainfed_Agriculture_2001.pdf&ei=qvx4T8v0OJTKiQK85M2nDg&usg=AFQjCNFxkkLdpNpbAIlKJgknD5rvDe93Bg&sig2=f3dVjKV45u_5uLracic_VQ Water harvesting for upgrading of rainfed agriculture. Problem analysis and research needs]. Stockholm International Water Institute.
===Manuals, videos, and links===
* [http://www.fao.org/docrep/W7314E/w7314e0q.htm Technologies for water harvesting and soil moisture conservation in small watersheds for small-scale irrigation], by R.K. Sivanappan.
===Acknowledgements===
* CARE Nederland, Desk Study: [[Resilient WASH systems in drought-prone areas]]. October 2010.
* Rufino, L., [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CFkQFjAB&url=http%3A%2F%2Fwww.saiplatform.org/uploads/Library/Technical%2Fuploads%2FModules%2FLibrary%2FSAI%2520Technical%2520Brief20Brief%25205202%252020%2520The20Rainwater%2520Importance20harvesting%2520of20%2520Soil20artificial%2520to20recharge%2520Water20to%2520Use20groundwater.pdf&ei=gf91T6GYJ-jWiAK7zuGnDg&usg=AFQjCNFDyR4mjTVCcvvTt-9v4OrxAZQfDA&sig2=iMzgbW0eK395na_V_YA4Kw Water Conservation Technical Briefs: TB 2 – Rainwater Harvesting and Artificial Recharge to Groundwater]. Sustainable Agriculture Initiative (SAI). August 2009.