In 1911, the Tennessee Power Company dammed the Ocoee River east of Cleveland, TN, and created the state's first artificial lake. TVA took over the company in 1939, and they've controlled the water level ever since. Nowadays, the river and lake are used mostly for recreation - the 1996 Olympic whitewater events were held there. (The whitewater center claims that it was the first Olympic whitewater event to be held on a natural river, but I'm not sure how natural it is if there's a dam controlling the flow.) The day I happened to drive through the gorge, the water was extremely low - the dirt in the photo is the lakebed.
The average life expectancy of a dam is 50 years. The one that controls this lake is 101.