The Tennessee Valley Authority, through its system of dams and reservoirs, averted more than $800 million in flood damage to communities along the Tennessee River and its tributaries in January, according to officials.
TVA is using its 49 dams to store and then gradually release water after what was the third largest recorded rainfall and runoff for a January in TVA history.
During the month of January, 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.
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, $710 million
· Lenoir City, $61 million
· Kingsport, $17.4 million
· Knoxville, $7 million
· South Pittsburg, $5.5 million
· Elizabethton, $2.9 million
· Clinton, $812,000
· Savannah, $73,000
During an average year, TVA’s reservoir operations avert approximately $250 million in flood damage. TVA estimates it has averted nearly $7 billion in flood damage since it completed its first dam, Norris Dam, in 1936.
TVA continues to release water to recover flood storage space at most of its dams including all nine dams on the Tennessee River. Excess water is also being released using spillway gates or sluice gates along with generators 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,” Mr. McCormick said.
A graphic depiction of TVA’s operation of the reservoir system is at http://www.tva.com/news/releases/janmar13/averted.html. Information on the river system and specific reservoirs is available on TVA’s Web site at http://www.tva.com/river and on TVA’s free app for the iPad, iPhone and Android devices. Links to download the apps are available at http://www.tva.com/mobile. For photos of various TVA dams spilling excess water, visit TVA’s Flickr site at http://www.flickr.com/photos/tennesseevalleyauthority.