Most dams are built to control flood hazards, to store water for irrigation or other uses, or to produce electricity. Along with these benefits come environmental costs including riparian habitat loss, water loss through evaporation and seepage,...

The design of hydraulic structures from small culverts to large dams requires engineers to calculate the amount of water that will flow through the channel along which the structure is built. The rate of flow through a stream channel, or discharge, is...

There are over 77,000 dams of significant size (over 6 ft [1.8 m] tall) in the United States, and tens of thousands of additional uncharted smaller dam structures. Constructed for the purposes of harnessing water resources for irrigation, water...

Raise the dam and the waters fill it....

Karun-3 dam, Iran. Hydroelectric dam in cross section. A dam is a barrier that divides waters. Dams generally serve the primary purpose of retaining water, while other structures such as levees and dikes are used to prevent water flow into specific...

China could face a catastrophe if it fails to quickly stop environmental problems such as flooding and erosion caused by the gigantic Three Gorges Dam, state media said Wednesday.The dam, China's showcase engineering triumph and the world's biggest hydropower project, has been relentlessly promoted as...

The Yangtze River gets more than half of China's industrial waste and sewage. Europe's Danube has lost most of its surrounding wetlands. And the Rio Grande has become so shallow that salt water is seeping in, bringing ocean fish that threaten freshwater species.Pollution, global warming...

Jay Minthorn remembers watching the Columbia River rise, the islands of Celilo Falls vanish, the fishing platforms wash away _ and a centuries-old way of tribal life vanish forever.The gates of The Dalles Dam had closed, and nothing would ever be the same."That was the...

A Pacific Northwest utility must build new fish ladders and take other steps to help salmon swim freely past four hydroelectric dams on the Klamath River if it wants to renew its license to produce electricity, federal fisheries agencies said Tuesday.The cost of the ladders,...