Going behind the scenes at TVA’s River Forecast Center

Learning about the team managing a 49-dam, integrated river system

Going behind the scenes at TVA’s River Forecast Center

KNOXVILLE, AL (WAFF) - TVA still has plenty of work to do in the wake of last month’s historic flooding, releasing water through their dams and using it to generate energy.

James Everett manages the Tennessee River Valley inside TVA’s River Forecast Center in Knoxville.

It’s staffed around the clock, 365 days a year, monitoring weather conditions and forecasts and constantly watching and adjusting the Tennessee River system.

The team manages a 49-dam, integrated river system to provide flood-damage reduction, navigation, hydroelectric power, water quality, water supply and recreation.

"Hour by hour decisions are made about how much water to release, how high lake levels are going to get, rainfall amounts," Everett explained.

We get asked for this animation all the time and we thought now is a perfect time to share it again. We continue to release water through our dams from historic rainfall in February and we're using the power of water to generate low-cost energy. Here is how we do it. #HydroPower

Posted by Tennessee Valley Authority on Tuesday, March 19, 2019

They get revised rainfall forecasts four times a day from the National Weather Service and adjust their strategy every six hours with changing weather conditions.

The team has stayed very busy over the last few weeks after record breaking rainfall in February.

"We essentially go to zero flow. So we shut flows down from these reservoirs, slow down that flow of water into the Tennessee River. Then we see the benefit of that in communities like Knoxville, Chattanooga, down through Huntsville and the Whitesburg, Ditto Landing below Guntersville and then on out through the Shoals area below Wilson Dam," Everett said.

There was significant flooding in Florence- the second highest regulated flood stage that TVA has seen in the history of managing the river system.

"It would have been much worse without the dams in place and our operation," Everett stated. "We stored significant amounts of water in the eastern part of the Tennessee Valley. Over 3 trillion gallons of water were stored during this event to reduce flood levels below the dams and in many locations like Whitesburg, Huntsville, Florence, areas of North Alabama."

They helped avert $1.6 billion in flood damages in February.

"At our tributary dams we store water. During a flood event, we turn off our large storage reservoirs like Norris, Cherokee, Douglas and Fontana. They are hundreds of miles away from North Alabama but as we turn those flows off, we're reducing flow into the Tennessee River, storing that water and providing flood damage reduction throughout the communities like Huntsville and the Shoals," Everett said.

Going behind the scenes of TVA's forecast center

Every single dam, all 49 of them, was impacted by the flooding last month. The River Forecast Center makes the call on how much water to release and when to release it in order to reduce flood damage. They do that by storing water in tributary dams.

“These other main river dams like Guntersville, Wilson and Wheeler, we do store water at those dams, however, they’re not built the same way as a tributary dam is. They just don’t store that much water. So when we get these record amounts of rain we utilize the maximum storage that we can at these dams, and then have to open spillway gates to move that water downstream,” Everett explained.

People were working around the clock at the dams, moving spillway gates and operating equipment 24 hours a day to manage flows.

"We had extra people working. Having a well trained and dedicated staff was really important to this," Everett said.

The River Forecast Center coordinates with the National Weather Service and EMA offices to spread information on how high river levels are and how high they may get.

They also communicate conditions with Redstone Arsenal as high river levels can impact operations and access.

Even though the heavy rains have let up, the staff at the River Forecast Center team still has a lot to manage.

"We're using this time now to evacuate flood storage through the system. That means we're using large volumes of water through our tributaries to get ready for more rainfall. We want to create that additional storage space," Everett added.

Management of the Tennessee River system using our integrated system of 49 dams across the region averted $1.6 billion in flood damages over the entire Valley. After the wettest February and fourth wettest month on record, we continue to manage high river and reservoir conditions to minimize flood impacts. (Video: Fort Loudoun Dam)

Posted by Tennessee Valley Authority on Friday, March 1, 2019

With April and May around the corner, they start thinking about recreation and having lake levels at adequate levels.

"Our focus can shift from day to day and a lot of it depends on the weather," Everett said.

The key distinction between reservoirs in North Alabama versus the tributary system in East Tennessee is that in North Alabama, the dams don't have a lot of flood storage capacity.

"They're very big lakes. They cover a lot of surface area but their storage capacity is very limited because those dams are not very tall," Everett stated.

It's important work with an impact on a very large scale.

“Areas all the way from Chattanooga to Knoxville and the entire tributary system which extends into Southwest Virginia, the Great Smoky Mountains of North Carolina, parts of North Georgia, there’s a tremendous drainage area of about 30,000 square miles and all that water, when big rainfall events happen, has to go down through the Tennessee River,” Everett added.

Over the past two weeks, we stored approximately 3.5 TRILLION gallons of water in all of our reservoirs to reduce downstream impacts. Now that the Tennessee River has crested and levels are falling from Knoxville to Perryville, Tenn., we are now releasing water from the big storage reservoirs like Fontana to prepare for more rain and recover flood storage.

Posted by Tennessee Valley Authority on Thursday, February 28, 2019

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