Last January, in particular, was the largest rainfall event in the last 60 years, TVA officials said during a visit to the Times-News.
“A lot of people hadn’t seen that kind of rain,” said Chuck Bach, TVA’s general manager of River Scheduling.
TVA’s response to swelled reservoirs across Northeast Tennessee was a choreographed opening and closing of dam spillways to move water downstream and avoid major flooding.
In one instance, a half-foot of rain left Watauga Lake in Carter County at its highest level since April 1987, according to Bach.
“As soon as we saw the lake level going up we immediately turned those turbines on,” Bach said. “We called the staff to open up those sluices (at the dam). We did it to where water would get right up to the edge of those (river) banks. We didn’t want to go outside of the banks because now we’re affecting people downstream. We moved as much water as we could without flooding people downstream. We’ve been doing that ever since we saw the rain. ... We flooded roads and golf courses but no one’s house.”
At Watauga Lake, Bach disclosed the water level was 30 to 40 feet from going over the top of the dam.
Other dams across the TVA system in East Tennessee — from Chattanooga to Bristol — experienced nine to 13 inches of abnormal rainfall.
TVA said it released 5.3 million gallons of water per second through its hydroelectric generators during the water drawdown.
During the January precipitation event, TVA was “spilling,” or releasing water from its dam system 25 days during the month.
That released water, according to TVA, produced about 3,300 megawatts of electricity — enough power for 1.8 million homes.
TVA projected its controlled water releases averted $800 million in damage to homes and property across its system.
Flooding was a serious problem in the Tennessee Valley before TVA dams and reservoirs were built during the Great Depression.
TVA attributed floods mostly to poor farming practices. Today, in an average year, TVA said its system prevents about $240 million in flood damage in the region and along the Ohio and Mississippi rivers.
The agency’s annual method of handling water goes like this: Controlled reservoir drawdowns occur during the fall. Winter and spring rain bring the lake levels to what TVA calls its “summer pool” for recreation.
“We’re using the water to our advantage,” Bach pointed out. “People would like to have full pools all year long. ... Reservoirs have crested and will start going back down. We have maximum capacity and when we get back to normal we will hold it there.”
The rest of the spring and summer, Bach said, look normal from a weather standpoint based on forecasts from the National Weather Service.
“If we stay normal, we keep the pool levels up and everyone can have a good season of summer recreation because it’s a great resource. ... We want them to enjoy it,” Bach noted.
Because of the large amount of water, TVA has been doing “health assessments” of all 49 dams — some being more than 100 years old.
“We do not expect any problems but this is a good way to confirm that there is no problem out there,” Bach said of the assessments.
For more, go to www.tva.gov.