TVA to Raise Height of 4 Dams

The Tennessee Valley Authority is moving to raise the height of four dams in eastern Tennessee with sand-filled containers after a new analysis suggested the dams could be topped by a worst-case flood.

TVA officials said Wednesday that such a flood is "extremely unlikely" and would have to be four or five times the size of the worst flood on record in 1857.

But they said new hydrology studies to support an operating license for a nuclear plant downstream in Alabama suggest the measures are necessary.

The federal utility plans to spend about $8 million analyzing all of its dams over the next year and to install temporary walls by January on the first ones examined at Fort Loudoun, Tellico, Cherokee and Watts Bar lakes.