700,000 To 1 Million Years
TVA plan for dams worries residents
Agency will hold meeting to hear from Tellico Village homeowners
Scott Barker knoxnews.com
Raising the height of Tellico Dam has raised concerns about flooding among residents of Tellico Village, the upscale lakefront development in Loudon County.
But Tennessee Valley Authority officials said the project would prepare Tellico and three other dams for a catastrophic, worst-case scenario that is unlikely to happen.
Over the next few weeks, TVA will complete a $6 million project that will temporarily raise the height of Tellico, Watts Bar, Fort Loudoun and Cherokee dams until construction begins to permanently raise the structures.
TVA officials will meet with Tellico Village residents at 7 p.m. tonight at the Tellico Community Church Fellowship Hall to discuss the project.
Ron Schuster of the Tellico Village Homeowners Association said lakefront property owners are worried that TVA is preparing to raise water levels.
"If they raise the water 20 feet, my boathouse would be under water," Schuster said.
Residents also say the temporary structures - wire baskets, lined and filled with sand - are unsightly and come dangerously close to the roadway.
"People are concerned about the possibility of a traffic accident," he said.
TVA officials say the residents shouldn't worry because the standard for dam heights is based on the largest flood possible, an unlikely scenario based on computer modeling that takes into account dam height, historic rainfall totals and the size of the reservoir.
Chuck Bach, TVA's general manager of river scheduling, said the work would prepare the dams for a "probable maximum flood" that would occur only once in 700,000 to 1 million years.
Under that scenario, "there will be catastrophic flooding everywhere. There would probably be water in Neyland Stadium if we had this event."
Bach said TVA follows Federal Emergency Management guidelines for dam safety that call on engineers to design dams for potential maximum floods.
"If we didn't do everything we could do to lessen the floods coming down the river, we're not doing our job," Bach said.
Bach said TVA uses computer models to estimate the size of a probable maximum flood based on the highest rainfall envisioned by the National Weather Service, climate, geography and other factors. New simulations run on those models show maximum flood levels two to three feet higher than the tops of the dams, he said.
According to Bach, three factors led to the change in the model results: TVA now holds water back when there's flooding downstream (where three nuclear plants are located); new data showed that less water went through spillways than previously thought; and a policy initiated in 2004 keeps initial water levels higher.
TVA is aware of traffic safety concerns and has talked to officials from the Tennessee Department of Transportation about solutions.
"It's on our radar, and we're meeting with TDOT to make sure we're doing it right," Bach said.
No federal stimulus money is going toward the project, which cost $2 million less than the initial estimate because Watts Bar Dam needed less work, he said.
TVA will take a couple of years to come up with a permanent solution, he said, and the construction schedule and price tag will depend on the design.
"I can't give you a time frame or cost," Bach said.
He said TVA hopes to provide answers for Tellico Village residents tonight. Answers are what they're looking for.
"It's a contentious issue here," Schuster said, "especially for the people who live on the lake."