Check dams are small dams made of various materials used for sediment and pollutant removal, irrigation, and livestock. They’re often built across storm drains, small streams, or swales. They’re practical in poor areas and used in bioswales to remove pollutants. Stone, rock, and log check dams are common types. They require frequent inspections and maintenance.
A check dam is a small dam that can be constructed of a wide variety of materials, including logs, rocks, and sandbags, and can be used for a variety of purposes, such as to provide an area for sediment, silt, or pollutants , such as garbage and heavy metals, to be deposited and removed from the water. This type of dam can also be used to slow the flow of water and hold back water for purposes such as irrigation, fish farming or livestock. Check dams are often built across storm drains, small streams, or in low-lying marshy areas called swales. Recommended specifications for a check dam are that it should be no higher than 2 feet (60 cm), that the center of the dam should be at least 6 inches (15 cm) lower than the edges, and that it should be used for drainage areas 10 acres (0.04 km2) or less. The construction of check dams is often easy and cheap, making them practical in poor areas with little financial and technological resources.
In developing countries, check dams are often used to increase agricultural production, replenish groundwater, and prevent soil erosion during heavy rains, such as monsoons. Check dams can also be used in man-made storm drains called bioswales which are often purpose built to remove pollutants from the water. The design of the check dam varies depending on the material used for construction, but the material must extend through the entire channel to be dammed and often some of the material must be incorporated into the soil to ensure that the dam remains in place even during flow of heavy water.
Three common types of check dams are stone check dams, rock check dams, and log check dams. A rock check dam is usually constructed with 8–12 cm (20–30 in) rocks, while stone check dams are constructed with smaller stones, commonly (2–3 cm) in diameter. A log check dam is constructed using logs 5-7.5 inches (4-6 cm) in diameter and the logs must be buried in the ground at least 6 inches (15 cm) deep. Sandbags are sometimes used to build temporary check dams, such as in the event of floods or very heavy rainfall.
A check dam requires frequent inspections, especially before and after heavy rains. The dam itself should be inspected for damage and wear, and the level of sediment behind the dam should also be measured. Such sediment can interfere with dam function and sometimes must be removed or the dam can fail.
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