TVA has responded system wide to the threat of potential flooding caused from heavy rain in the aftermath of Hurricanes Harvey and Irma.
The River Forecasting Center dropped water levels on the main river ahead of the storms to put the region in a position to combat torrential rainfall, according to a TVA news release.
“We lowered much of the main river ahead of those storms so that we had ourselves in a good position if we were going to get the kind of torrential rainfall that’s been associated with other hurricanes,” said James Everett, River Forecast Center Operations support manager. “As it turned out, we got fortunate and flooding along the Tennessee River was a non-issue.”
In the weeks since, the weather has been dry, with rainfall at only 15-20 percent of normal levels — and the outlook for October is looking dry, too.
Now, TVA is releasing water from the tributary lakes into the main stem river system slowly and steadily to meet not only winter flood guide targets, but also to ensure water quality and electric generation.
“Another thing we’re working hard on right now is coordinating water levels to maintain minimum depths for navigation,” Everett said in the release. “We have to consider the Tennessee River, but also conditions on the Ohio and Mississippi, which do have a big impact on our coal plants and barge movements in the Tennessee and Cumberland valleys. We need to make sure barges can get through the entire inland waterway system with minimal problems.”
Water temperature is an issue now — whereas a cool snap in August was favorable for operations, now flows must be sufficient to keep river temps under control at nuclear and fossil plants. So, too, are dissolved oxygen levels and water quality under careful observation.
“We are always maintaining our minimum flows to support aquatic life,” Everett said.
Everett said the operation would be a slow and steady one, though officials remain mindful of recreation.
“We’re still doing recreation releases; we’ll continue them for the Ocoee into October,” he said. “We just accommodated a large Iron Man event in Chattanooga, and we receive flow requests for bass tournaments and we try to work with them if the weather is favorable — we take them on a case-by-case basis.”