The Tennessee Valley Authority opened up the spillways on most of its 49 dams this week to help draw down upstream reservoirs ahead of rain storms expected to dump anywhere from 3 to 5 inches more of rain on the region, starting this weekend.
TVA was spilling 115,000 cubic feet per second of water, or more than 860,000 gallons a second, through the Chickamauga Dam in Chattanooga on Tuesday in anticipation of two storm fronts expected in the next week. The spilling lifted the Tennessee River nearly 6 feet above its normal winter level in Chattanooga, and the heavy currents forced the shutdown of river navigation through the Tennessee River gorge just west of Chattanooga.
"We're using this week when we are having mostly dry weather to recover some of our storage on our tributary system," James Everett, manager of TVA's River Forecast Center, said Tuesday. "When the rains start coming in Friday and Saturday, we'll start holding back water at these dams and use them to help limit any flooding during the heavy rains we are expecting this weekend and again early next week."
The Army Corps of Engineers, which controls the locks and helps regulate river navigation on America's inland waterway system, limited the Tennessee River to barge traffic west of Chattanooga on Monday when TVA increased the river flow. Everett said TVA expects to continue the spilling on its mainstream dams through Friday.
River barge operators are eager to get a reprieve from the rains that threaten to block shipments through Chattanooga. Last February when record rains fell in the Tennessee Valley, the Tennessee River in Chattanooga was shut down for weeks.
"Hopefully, this will be short-lived and not like last winter," said Peter Serodino, owner of the Serodino Shipyard in Chattanooga, which was forced to idle its barges in Chattanooga on Monday. "The rains coming this weekend are worrisome, but we're keeping our fingers crossed."
Cline Jones, executive director of the Tennessee River Valley Association, said TVA needs to release water upstream to create reservoir storage for bigger rains ahead.
"It's not looking good," Jones said of the short-term forecast for barge traffic in Chattanooga.
TVA, which controls the flow of the Tennessee River and its tributaries through its network of 49 dams, manages the river for flood control, navigation, power generation and recreation. Last year, TVA estimates it prevented $1.8 billion in flood damages, including $1.6 billion in damages in Chattanooga, which TVA projects would have occurred without its dams and river management operations.
The heavy flow of the Tennessee River this week shut down all piers at the Tennessee Riverpark in Chattanooga and flooded many low-lying areas around Savannah, Perryville, Tennessee, and Pickwick Lake in West Tennessee, Everett said. But the flooded farmlands were not as costly as flooding cities like Chattanooga.
"Obviously, anyone who chooses to get out on any of our lakes should be aware that river flow levels are much higher than normal, so we urge people to use extreme caution," Everett said.
As of midnight Monday, TVA had about 90% of normal storage capacity on its TVA reservoirs following 3 inches of rain last weekend. In the first week of the year, rainfall in the Tennessee Valley is already more than twice the normal levels with heavy rains expected starting Saturday.
The start of the new year is similar to a year ago when heavy winter rains flooded parts of the Tennessee Valley and shut down river navigation for weeks following record February rains that helped push up the total rainfall for all of 2019 to the second highest level on record.
The wettest year on record in the Tennessee Valley was in 2018 when more than 67 inches of rain fell in TVA's seven-state region, or more than 15 inches above normal.
Contact Dave Flessner at firstname.lastname@example.org or at 423-757-6340.