Hydropower is energy collected from flowing water that's converted into electricity or used to power machinery. The ancient Greeks used water wheels for grinding wheat into flour, and by the 1700s, water turbines were employed to harness the energy of flowing water. Today hydropower generates more electricity in the United States than any other renewable energy source, and the Department of Energy's Wind and Water Power Program promotes and accelerates its use throughout the country.
A primary use of hydropower energy is to produce electricity. The main ingredients of hydroelectric power plants are dams, rivers and turbines. Plants use dams to create reservoirs where the water is stored. This water is then released through turbines and spun to activate generators and create electricity. The first hydropower electrical systems were developed in the 19th century and used direct current technology to light Michigan theaters and shops. America also spearheaded the use of alternating current technology in the world's first hydroelectric plant in Wisconsin in 1882.
One of the major advantages of hydropower plants to the wider community is that by law the facilities must be open to the public, and many plants offer a wide range of recreations including swimming, fishing and boating. The largest American operator of hydroelectric power plants is the U.S. Army Corps of Engineers. The Corps's 75 bases have an installed capacity of about 21,000 megawatts -- that's 24 percent of the nation's hydroelectric output. The Corps is also the biggest federal operator of outdoor leisure activities in the country, providing 33 percent of all freshwater fishing opportunities. There are thousands of boat launch ramps and 20 annual fishing tournaments at their largest parks and lakes. The Army Corps is also committed to preserving a healthy stock of fish.
Flood Risk Management
Hydropower energy is also employed in flood risk management. There are 94 million acres of land in America that are vulnerable to floods, and the plants play a major part in preventing them and practicing damage limitation. In 2010, working alongside teams at the University of Washington, the U.S. Army Corps updated the flood risk management program at the Columbia River basin, the country's largest hydropower system. A key factor in flood risk management is knowing exactly when to empty the basins in preparation for winter weather and when to refill them in the spring to store water for the year to come. The new system not only reduces any flood risks but also helps fish stocks by filling reservoirs in a more reliable way.
Thousands of miles of irrigation canals in the United States are responsible for watering more than 60 million acres of crops, orchards and vineyards. Hydropower dams divert water for irrigation; in Colorado, 3 million acres of irrigated land use more than 12 trillion gallons of flowing water. The government awarded a $50,000 grant to Colorado State University to research new technologies that can use even these shallow depths of flowing water to generate power and tap into this underused resource.