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TVA opens spill gates of all nine dams in Tennessee River system

(from Dec 8 – McClatchy-Tribune Regional News – Suzanna McCloskey The Knoxville News-Sentinel, Tenn.)

Responding to recent heavy rainfall, the Tennessee Valley Authority opened the gates Wednesday at Fort Loudoun Dam, making it the last of the nine dams in the Tennessee River system to start spilling.

The other eight dams have been spilling for a little more than a week, but earlier rain hadn’t impacted Fort Loudoun until now. Workers on Wednesday opened nine of the dam’s 14 gates.

Parts of the Knoxville region have recorded close to 2 inches in rainfall so far this month, figures show. Precipitation already was 5 or more inches above normal.

Fort Loudoun’s release should last about a week.

The action is part of TVA’s normal operating procedures detailed by reservoir operating guides, careful instructions for each reservoir about moving water through dams. Spokesman Travis Brickey said the last time all nine Tennessee River dams were in a spill operation was in April.

“It’s kind of like playing traffic cop,” he said.

Brickey explained the TVA starts “drawing down” the reservoirs after Labor Day in preparation for creating water storage for historically rainy winters and early springs.

He said reservoirs are typically allowed to refill beginning in mid-March so they can reach their peak levels by June 1.

“We try to keep the reservoirs full throughout the summertime, and then we start the whole cycle over again,” Brickey said.

The controlled release discharged approximately 22.5 million gallons of water per minute out of Fort Loudoun on Wednesday. Brickey said higher spill rates are forecast for today.

If the water begins moving too swiftly, TVA will close the 60-foot by 360-foot lock at Fort Loudoun that allows rivercraft to pass from its reservoir into Watts Bar Reservoir and vice-versa.

Rain isn’t the only contributor to high reservoir levels. There’s also runoff.

Trees and shrubs soak up water in the summertime, but those plants are now dormant, meaning the water can’t soak into anything.

“We have a lot of runoff and a lot of rain, so we’re having to move a lot of water through the main stem of the Tennessee River,” Brickey said.

He said TVA’s first priority is to draw as much energy created by water flowing through the system as possible.

“Anytime we are in a spill operation, our (generators) are at full capacity. In this case, we can’t move enough water just using (generators),” Brickey said.

He said spilling won’t affect fishing but advised people to be especially cautious around dams in a spill operation.