Fontana Dam on the Little Tennessee River is a multi-purpose dam 480 feet high, the Tennessee Valley Authority’s highest. Begun soon after Pearl Harbor, it was completed in less than three years. Water stored there helps control floods, and released water generates electricity and helps maintain navigation depths on the Tennessee. The Tennessee River has its headwaters in the mountains of Tennessee, Virginia, North Carolina, and Georgia, and its main stream forms at Knoxville, where the Holston and the French Broad Rivers join. The valley, covering 41,000 square miles, receives an average of 52 inches of rain a year. In terms of water discharged into the Ohio and Mississippi, the Tennessee River is about equal in size to the Missouri. The Tennessee Valley Authority has harnessed the river with a multi-purpose system of dams and reservoirs that regulates floods, improves navigation, and generates electric power. High dams on the tributaries create large storage reservoirs that hold back flood waters, releasing them when necessary to maintain navigation depths downstream while also generating electric power, and the system also helps protect the lower Ohio and Mississippi valleys. The nine main river dams, with their locks, form a navigation channel 650 miles long from Knoxville to the Ohio River, an important arm of the nation’s inland waterway system connecting 20 states. Having developed virtually all the river’s power resources, the Tennessee Valley Authority has also built huge coal-burning steam electric plants to help serve the region’s growing power needs. Its power is sold at wholesale to cities and rural electric cooperatives, which in turn distribute it at retail to homes, farms, business, and industry, while a few industries and U.S. Government defense installations that use large amounts of power are served directly. The largest of these, using more power than a great city, are the atomic plants at Oak Ridge, Tennessee, and Paducah, Kentucky.