Overview

Dams have been used to control river flow since the time of the ancient Egyptians, but it was not until the twentieth century that the full potential of harnessing this natural resource was realized. Hydroelectric power has garnered a great deal of attention since the early 1900s as a clean and renewable source of energy. Traditional fossil fuels are expensive, have a finite supply, and produce a great deal of pollution. The extraction of substances like oil and coal is often damaging to the environment. During the early to mid-1900s hydro projects provided as much as 40% of the electricity consumed in the United States. Today, waterpower supplies about one-tenth of the electricity consumed in the U.S. and about onequarter of the world's electricity. The leading producers of hydroelectricity are Canada, United...