• DES MOINES, Iowa (AP) -- On a typical summer weekend, hundreds of boats glide across the shimmering surface of Iowa's Lake Red Rock, the state's largest body of water.
• The placid 15,000-acre lake was created in the 1960s after the government built a dam to prevent frequent flooding on the Des Moines River. Now the cool waters behind the dam are attracting interest beyond warm-weather recreation. A power company wants to build a hydroelectric plant here -- a project that reflects renewed interest in hydropower nationwide, which could bring changes to scores of American dams.
• Hydroelectric development stagnated in the 1980s and 1990s as environmental groups lobbied against it and a long regulatory process required years of environmental study. But for the first time in decades, power companies are proposing new projects to take advantage of government financial incentives, policies that promote renewable energy over fossil fuels and efforts to streamline the permit process.
• "We're seeing a significant change in attitude," said Linda Church Ciocci, executive director of the National Hydropower Association, a trade group.
• The Federal Energy Regulatory Commission, which oversees hydroelectric projects in the U.S., issued 125 preliminary hydropower permits last year, up from 95 in 2011. Preliminary permits allow a company to explore a project for up to three years. The agency issued 25 licenses for hydropower projects last year, the most since 2005.
• In all, more than 60,000 megawatts of preliminary permits and projects awaiting final approval are pending before the commission in 45 states.
• "I've never seen those kinds of numbers before," Church Ciocci said.
• The interest in hydropower is so intense that some utilities are competing to build plants at the same dams, leaving the government to determine which ones get to proceed.
• Hydroelectricity provides about 7 percent of the nation's power using about 2,500 dams. But those dams are just a fraction of the 80,000 in the United States. Most were built for flood control, to aid in river navigation or to create recreational areas. So they do not have power plants.
• The Department of Energy concluded last year that the U.S. could boost its hydropower capability by 15 percent by fitting nearly 600 existing dams with generators.
• Most of the potential is concentrated in 100 dams largely owned by the federal

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