The Tennessee Valley Authority (TVA) averted more than US$800 million in flood damages to communities along the Tennessee River and its tributaries through its dam management programs in January.

The Knoxville-based agency said it used its system of 49 dams to corral what was the third largest recorded rainfall and runoff for a January in TVA's history, with areas in eastern Tennessee receiving approximately 10 inches of rain and the western part of the state averaging about eight inches of rain.

"We hold water behind the dams in order to minimize downstream flood impacts," said John McCormick, Senior Vice-President of TVA's River Operations and Renewables. "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."

Using computer flood modeling, water elevation calculations and property value assessments, TVA was able to estimate damages if its dams didn't exist.

According to TVA, estimated structural damages averted include:

  • Chattanooga: $710 million
  • Lenoir City: $61 million
  • Kingsport: $17.4 million
  • South Pittsburgh: $5.5 million
  • Elizabethton: $2.9 million
  • Clinton: $812,000
  • Savannah: $73,000

TVA's reservoir operations avert a reported $250 million in flood damages per year, equating to approximately $7 billion in flood damage protection since its first dam was completed in 1936.

Excess water is still being released using spillway and sluice gates with generators operating at maximum capacity at all of TVA's 29 hydropower-generating dams. TVA said the releases equate to about 3,300 MW of electricity.

"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," McCormick said. "This is a perfect example of why TVA lowers the reservoirs to their lowest elevations during the fall and winter months."

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