The Ocoee Gorge sprang a spectacular waterfall Wednesday morning when a new rock slide took out 60 to 70 feet of TVA's historic Ocoee flume system.
Unlike a slide last fall that closed U.S. Highway 64 across the river gorge and several miles upstream, this slide probably won't cause detours affecting the region's reeling rafting business.
"With the flume down, they may get some additional rafting days," said Tennessee Valley Authority spokesman Travis Brickey. "Our engineers and geologists are making assessments now, and the geologists could say the rocks up there are too unstable for anyone to be rafting below. But there will definitely be more water (in the river.)"
TVA officials said there were no injuries, and Mr. Brickey said the agency expects minimal impacts to electric power generation.
The Ocoee Flume, built in 1912, diverts water from the river several days a week and carries it by gravity to sudden drop points above a powerhouse that uses the force of the falling water to make electricity. When the flumes are running to make power, the river is dry.
It was a shutdown of the flume in 1976 to repair structural problems that brought the rafting industry to the Ocoee in the first place. With the water running freely for the first time in decades, whitewater rafters discovered the river.
In the years since, TVA and rafters gradually have negotiated a schedule to accommodate both industries.
On Wednesday, Keith Jenkins, owner of Quest Expeditions and president of the Outfitters Association, said rafters already had been talking with TVA and Tennessee Department of Environment and Conservation officials about the slide's impact.
"Any additional water days would be a good thing," he said. "We should know over the next few days."
Tisha Calabrese-Benton with the department said Tennessee state park officials will adjust ranger schedules and work locations to allow outfitters to take advantage of some of the extra flow if the rock is found to be stable.
"We still need to work out the details with TVA and the outfitters, and we need to be conscious of our budget," she said. "However, we think we can make the necessary adjustments to provide six hours of oversight at the (raft) put-in on days that normally would have been 'off' days."
Assessing the slide
The cause of the slide was unclear Wednesday, but the region was pelted with heavy rain last week, and a 3.3 earthquake shook Maryville, Tenn., about 60 miles northeast of the gorge, on April 20.
The November slide that closed U.S. 64 also was preceded by heavy rains and a 3.0 earthquake near Cleveland, records show.
As TVA and other agencies survey the damage and test remaining systems in coming days, they are keeping the weekend's rain forecast in mind, Mr. Brickey said.
"Heavy rains are forecast for this weekend," he said. "We will notify (state park rangers) if this rain will result in flows in excess of 3,000 cubic feet per second. That's the point where rangers would shut down rafting."
The river's normal flow is less than half that rate, he said.
Mr. Brickey said the assessment will determine how long repairs might take and what they might cost.
The wooden flume is built high on the side of the gorge, many yards above the river. Work crews access it by rail lines built atop the flume itself.
"Until the flume is repaired, we will lose ability to generate a total of 23 megawatts of power," Mr. Brickey said.
"I've no idea how long it will take for the assessment to be complete, but I'm sure it will be in-depth," he said.