Managing Heavy Rains

With up to seven inches of rain in many locations over the past seven days, TVA’s River Management teams worked around the clock to avert flood damages across the Valley.

FEBRUARY 12, 2018—TVA went into action before the weather pattern began to unfold, using storage at Cherokee, Douglas, Fontana and other tributary reservoirs to store water during the rain and keep it out of the main stem of the Tennessee River to reduce flooding.

Tom Barnett, general manager of River Management says TVA increased spilling (releasing water over above-water retention gates) at most main river dams across the weekend as the rain continued to accumulate across the Valley. As of Monday morning all main-stem Tennessee River dam were spilling except Fort Loudoun and Watts Bar. Watts Bar is expected to begin spilling Monday afternoon with Fort Loudoun close behind.

River management gate changes for pool and flood control continued today on main stem river dams such as Kentucky Dam, shown here.

According to Barnett, continuing adjustments—including spilling and sluicing (releasing water through underwater tunnels built into the dam)—at tributary reservoirs like Norris, Melton Hill, Ocoee #1 and #3, Apalachia, South Holston will be necessary this week as TVA releases water from these dams to recover flood storage.

“We always prepare in advance for rain events such as these,” Barnett says. “Averting flood damages is part of our TVA mission of service.”

TVA teams used generating turbines and spillways to release up to a million gallons per second at some locations, while holding back and storing water in some tributary reservoirs to reduce the flood crest on the Tennessee River. TVA’s Hydro Generation staff worked tirelessly throughout the weekend to operate spill gates and help TVA achieve its power generation and river management objectives, Barnett said.

TVA’s River Management System includes 29 hydroelectric dams and 20 non-power dams and averts about $240 million in flood damages annually. TVA has helped avert more than $7 billion in flood damages since 1936.

Rainfall from this event has tapered off across most of the Valley with a few lingering showers in the eastern portion, with only about half an inch forecast over the next few days in most areas.

Though the worst has passed for now, waters will continue to rise in some places. Levels at Savannah, Tenn.,  have exceeded the National Weather Service Flood Stage and will continue to rise for the next day or so. Levels at Florence, Ala., are currently expected to rise slightly above Flood Stage overnight. Levels at Clifton and Perryville, Tenn. are forecast to approach Flood Stage middle of this week. TVA’s River Forecasting Center is adjusting releases to minimize flood crest levels and continuing communications  with external agencies, the National Weather Service and other  stakeholders in and outside the TVA service area.

The River Forecast Center

TVA’s River Forecast Center—located in Knoxville, Tenn.—is staffed around the clock, 365 days a year, monitoring the river to control flooding, as well as water quality data, availability and demand—all with the goal of routing water through the system to provide the most public value given changing weather conditions and water demands. Read more about the River Forecast Center.