The Tennessee Valley Authority says it avoided more than $800 million in flood damage to communities along the Tennessee River and its tributaries in January.
During days of heavy rain in January, TVA used its 49 dams to store and then gradually release water to prevent flooding.
During the month of January, TVA says the eastern part of the Tennessee Valley, including Knoxville and the Tri-Cities area, received approximately 10 inches of rain and the area below Chattanooga and West Tennessee averaged about 8 inches of rain.
"We hold water behind the dams in order to minimize downstream flood impacts. After the high water crested on the Tennessee River and its tributary rivers, we started gradually releasing water out of the tributary reservoirs to recover storage space and to prepare for the next rain event," said John McCormick, senior vice president, River Operations and Renewables.
According to a press release, TVA engineers use computer flood modeling, water elevation calculations and property value assessments along the Tennessee River and its tributaries to determine flood water impacts if TVA dams didn't exist.
Areas estimated to have the most structural damage averted in January 2013 are:
- Chattanooga, Tenn., $710 million
- Lenoir City, Tenn., $61 million
- Kingsport, Tenn., $17.4 million
- Knoxville, Tenn., $7 million
- South Pittsburg, Tenn., $5.5 million
- Elizabethton, Tenn., $2.9 million
- Clinton, Tenn., $812,000
- Savannah, Tenn., $73,000
In an average year, TVA estimates it averts around $250 million in flood damage. Officials believe they've saved nearly $7 billion in flood damages since Norris Dam was completed in 1936.
All nine TVA dams on the Tennessee River are still spilling to make room in the reservoirs in case they need to store more rainwater. In addition, excess water is being released using spillway gates or sluice gates, and generators are operating at maximum capacity at all 29 hydro generating dams, producing about 3,300 megawatts of electricity. That is enough to power about 1.8 million homes.
"We try to avoid spilling water because it's low-cost power generation, but when we have a lot of water our No. 1 priority becomes reducing flood damage risks. This is a perfect example of why TVA lowers the reservoirs to their lowest elevations during the fall and winter months," McCormick said.