FEBRUARY 18, 2020 — TVA used a break in the rainfall over Valentine’s Day weekend to start recovering storage capacity in its reservoirs in preparation for even more rain in this week’s forecast.
James, Everett, Senior Manager, TVA River Forecast Center, said even with a few days respite, TVA river management teams continue to work 24/7 to help reduce high water levels and manage flows across the Tennessee River system.
“The rain stopped for a few days, but we continued to stay very busy managing heavy inflow and runoff across the Valley,” Everett said. “Some locations along the mainstem Tennessee River crested over the weekend and we will continue high flows in order to get mainstem reservoirs back down to normal winter pool levels as well as pass large volumes of water being released from tributary dams.”
For most of this month, TVA has curtailed flows and stored as much water as possible in upper mainstem and tributary reservoirs to help provide flood relief downstream of dams all across the Valley, especially along the mainstem Tennessee River in north Alabama and in the Savannah, Tenn. area. Norris Reservoir, for example, has risen 20 feet above normal winter pool in the last two weeks, Everett said.
“We’ve stored enormous amounts of water in our tributary reservoirs in East Tennessee, Georgia and North Carolina for the last two weeks, and this has provided a tremendous benefit all across the Valley,” Everett said.
With Friday’s break in rainfall, TVA was able to begin aggressive releases from tributary dams, with additional spilling and sluicing to recover flood storage to help manage the additional 1-2 inches of rainfall expected this week. Flows through mainstem dam also were increased to keep pace with increased inflows from TVA tributaries and unregulated streams, creeks and runoff, which continue at increased flows even after the rain stopped falling.
Rainfall more than 300% above normal the first half of February has caused moderate to major flooding along the lower mainstem Tennessee River. So far this month, the Tennessee Valley has seen on average more than eight inches of rain, with some areas already receiving more than a foot. That amount is on track to challenge the record 11.6 inches of February 2019.
Despite the recent rain-free days, navigation closures remain in place at Chickamauga and Watts Bar Lock and the Nickajack Gorge section. Outside the Valley, the Ohio River at Cairo, Ill., remained above flood stage. TVA is coordinating flood control operations with the U.S. Army Corps of Engineers Lakes and River Division.