Dams provide electricity, water, flood control and irrigation.
But they have also wreaked havoc on people, ecosystems and animals, and have seldom delivered on promises, according to a report by the World Commission on Dams released Nov. 16. The 12-member Commission included representatives from industry, dam owners, government and environmentalists, with two members from the United States. It was established by the World Bank and the World Conservation Union and began its work in 1998. In its research on the impact of dams, the Commission focused mostly on nine large dams, including Grand Coulee Dam on the Columbia River in Washington, as being representative of the world's 45,000 large dams. In addition to the benefits dams were meant to provide, the Commission found that they also caused significant negative social and environmental effects that developers never assessed before construction.