Water management | How TVA Handled Billions of Gallons of Water During Hurricane Helen

KNOXVILLE, Tenn. (WVLT) – From the early morning of Thursday, September 26th until Sunday, September 29th, Tennessee Valley Authority employees worked around the clock to deal with the billions of gallons of water flowing from the clouds of Hurricane Helen.

Rainwater flooded parts of western North Carolina and parts of eastern Tennessee, killing more than 100 people in the two states and causing millions of dollars in damage.

“No, in terms of rainfall amounts, intensity and location, I have never seen or experienced that,” said Darrell Guinn, senior manager of the TVA River Forecast Center.

The TVA system consists of forty-nine dams, as well as 40,000 miles of rivers and 650,000 acres of reservoirs.

“What we do, I’ve actually broken it down into five buckets: our manufacturing, we supply power to the valley below, we control floods in the valley, we provide recreation through our rivers and lakes, we provide navigation up and down on the Tennessee River, we ensure the quality of the water, so many people get their water from the Tennessee River, so we ensure the quality of the water,” said plant manager Eric Bodyscomassink.

WVLT met Bodyscomassink at the top of Douglas Dam, nearly a month after Helen’s floodwaters settled in the lake it holds and then flowed through its floodgates and down into the Tennessee River valley.

“Douglas can really take it in, but we saw they were saying Douglas was getting more water than Niagara Falls, so we weren’t sure how much flow was coming in, so we started opening our spillway gates on Friday,” said Bodycom.

Every gate that Douglas had was open, and billions of gallons poured out and down into the valley.

“Never, never, we hardly ever spill water, maybe once every three or four years here in Douglas, and I’ve never seen this much water come into Douglas, and I’ve never seen us spill this much water.” , said Bodycomassink. “We spilled about 62,000 CFS I think from Douglas, I’ve never seen that many.”

It became increasingly difficult to know how much water was coming in due to the loss of water meters along the Nolichatsky River.

The Nolichaki is known to have gone over the dam near Greenville during the worst of Hurricane Helen.

“We know if Walters is exceeding and there is a lot of flow coming from Nolichucky,” Bodyscomassink said.

Every movement made in Douglas was coordinated 27 miles to the west inside the TVA towers in downtown Knoxville.

“So we kind of prepared for that, so it was a lot of the same thing: We continued to monitor the precipitation as it continued, where it rained, how long it rained, and then assessed the conditions and made changes to operations to a lot of things like that. It just happened around the clock and we continued to do it throughout the event,” Guinn said.

The River Forecast Center is a floor inside TVA’s West Tower that monitors every dam, lake and river in the TVA system, tracking water flows and water levels.

“We had a great staff, they worked to their training, they responded well to all the training that they received during their experience here at TVA,” Guinn said. “Officers and staff responded as they were trained, everything went to plan, additional people were brought in to help respond, but it was a busy time for about 48 hours.”

Their work was also complicated by the loss of important instruments, but working with the Army Corps of Engineers and the U.S. Geological Survey gave TVA an idea of ​​what was happening many miles away.

“That was one of the issues that we had to deal with, so we were prepared, we had backup scripts for transmitting this data, the satellite data that is being transmitted into our system. So we responded by putting them into action. They responded accordingly, and with the expertise of the engineers here, they were able to incorporate the data into the plan and predict what we needed to know,” Guinn said.

The only thing that saved the system was the timing of the rain.

Historically, TVA draws lakes by Labor Day, in early September.

“You know, that’s why we’re doing this, that’s why we’re lowering our lakes, you know a lot of people who have homes, lakefront properties, they see us lowering our lakes, but they don’t know why, Hurricane Helen was a perfect example of why we are abandoning our lakes,” Bodyscomassink said. “Imagine if we hadn’t dropped our lakes, if we had been in the summer pool and maintained our lake, we wouldn’t have absorbed the 22 feet of water that went into that lake. He would go down the river, go as far as Knoxville, as far as Chattanooga. They predicted Chattanooga would be 15 to 20 feet under water, which really explains why we’re sinking our lakes.”

Random timing, but also knowledge gathered over almost a century on how to deal with Mother Nature and her evil ways.

Although the eastern parts of the valley were not spared Helen’s worst impact, the TVA system protected almost everything below.

By TVA’s own estimates, the system of dams, lakes and reservoirs prevented $406 million in damage from the Helen flood, and over the life of TVA, it has prevented nearly $10 billion in flood damage.

Copyright WVLT 2024. All rights reserved.