Historic plant soon to be back online

Historic plant soon to be back online

February 19th, 2011 by Pam Sohn in News

It's been 10 months on the high wire for Wylie Hamby, Jeff Munsey and other TVA workers who have labored to rebuild a 100-foot section of the Ocoee hydroelectric plant flume that was smashed last April by a rock slide.

"From 100-degree days in the summer to a couple of double-digit-inch snowfalls, these guys have been out here every day doing a great job of working through some really extreme conditions," said Munsey, the flume repair project manager.

Now the repair crews are just a few weeks away from bringing the historic power plant -- which makes electricity with gravity and water -- back online.

Work crews access the flume by rail lines built atop the flume itself, and on Friday, amid sounds of squealing rails and hammering, Tennessee Valley Authority showed off its work to restore production of 20 megawatts of power.

That's enough electricity to run about 11,700 Tennessee Valley homes from the hydropower system originally constructed in 1912, said TVA spokesman Travis Brickey.

Staff Photo by Dan Henry/Chattanooga Times Free Press A rail line runs on top of the Ocoee Dam No. 2 flume that was damaged last year by a rockslide.

"It may not sound like a lot of power, but the Ocoee plant is a very important part of TVA's power mix," said Brickey, noting that hydropower is both green and cheap to make.

The repair is expected to tally between $2 million and $3 million, Brickey said.

The cause of the April 28 slide that took out the flume was unclear, officials said at the time.

But the region was pelted with heavy rain the week before, and a 3.3 earthquake shook Maryville, Tenn., about 60 miles northeast of the gorge, on April 20.

In repairing the smashed portion of the flume, TVA also had to repair the bluff where the flume -- a five-mile wooden trough -- carries water several hundred feet above the Ocoee River Gorge.

"The first order of business was to take loose material down from the slide," Brickey said. "Then we used rock bolting to stabilize the cliff."

On Friday, workers were hammering in tongue-and-groove side panels on the Interstate-lane-sized flume.

"The flume is 14 feet wide and 11 feet deep," Brickey said. "And when it's filled, the water goes right to the top. It carries a lot of water."

In fact, when the flume is allowed to run, it completely dries the Ocoee River below.

While the flume has been dry and repairs have been under way, TVA crews also worked to clean out the undamaged portion of the flume and do maintenance work on the powerhouse.

"They have been manually turning the turbine wheels once a week to keep them from warping," Brickey said.

The flume is on the National Register of Historic Places, but Brickey said that didn't hinder the repair.

"The historic designation plays a part most definitely, but wood is a good material for this," he said. "We keep water in the flume all the time, and the wood swells and creates a natural seal, so it's very effective."

Because the flume has been dry since the rock slide, workers expect it to leak for a time over its entire five-mile length when they refill it.

"The wood's not swollen any more," Brickey said. "But as time goes on the flume will seal itself."

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