This article is about structures for water impoundment. For other uses, see Dam (disambiguation).
Hoover Dam, a concrete arch-gravity dam in Black Canyon of the Colorado River. Lake Mead in the background is impounded by the dam.
Glen Canyon Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees (also known as dikes) are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are often used in conjunction with dams to generate electricity. A dam can also be used to collect water or for storage of water which can be evenly distributed between locations.