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. These structures are relatively cheap and can last about 2-5 years.
==Suitable conditions==
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.
==Reference 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.
