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Wednesday, 24 March 2010 19:03

Engineers stumped on best way to shore up Maggie slide

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With federal and state grants in hand, work will soon get underway to stabilize the remnants of a massive landslide still looming precariously over Maggie Valley.

“You can see the cracking of the soil. It is obviously very unstable and just hanging there, if you will,” said Mike Hinton, manager of the federal Emergency Watershed Protection Program administered by the Natural Resources Conservation Service office in Raleigh.

The landslide originated from Ghost Town in the Sky, a mountaintop amusement park, and damaged five homes along its 3,000-foot path. But several other households are in the potential line of fire if the remaining portion of the mountainside gives way, essentially leaving them without a home until something is done to fix the unstable slope.

A chief concern right now is spring rain. A good, soaking rain could easily trigger a second slide, which makes time of the essence, Hinton said. But not at the expense of a carefully crafted plan.

“I know it is an emergency, and I know the people who are out of their homes are anxious for work to be started. I know if I was in their shoes I would be thinking ‘This is taking forever,’” Hinton said. “But at the same time, we need to make sure that whatever we do does not cause further damage and takes into account the workers’ safety.”

While a second slide would certainly solve the problem of trying to stabilize the precarious slope — it would simply come crashing down on its own — a second slide could be even worse than the first one.

Only a portion of the slope collapsed in the first slide. Far more is still vulnerable.

While a second slide would likely follow the same route down the mountain, it would be deeper, wider and faster — and travel further. Houses unscathed last time could be taken out by a second slide, Hinton said.

Plus, giant piles of dirt and debris left in the landslide’s track would get caught up in a second slide, creating even more momentum, Hinton said.

 

A daunting challenge

But figuring out how to shore up the remaining mountainside remains elusive. Clearly, it can’t all be stabilized in place. Some will have to come down, Hinton said.

“That is easier said than done: how do you remove it?” Hinton said. “That part is really the dilemma.”

A contractor who was at Ghost Town the same day Hinton was surveying the site said he was willing to get on his dozer and just start pushing dirt off the side. But if the whole slope began to give, the man on the dozer would have had a wild ride to the bottom.

Hinton said it would be impossible to be stationed on the slope itself while performing the work. Equipment would have to far from the edge and on stable ground. But from that far back, could it reach out far enough to knock loose the unstable part?

Another option is evacuating everyone who lives below and blasting the soil off — not in one big blast but a series of smaller, controlled blasts.

“But who is to say one little blast wouldn’t trigger the whole thing?” Hinton said. So that option would likely be frowned on.

Simply coming up with an estimate was challenging. They obviously couldn’t scamper along the face of the slope. Hinton wasn’t willing to stand at the bottom and look up at it either. So all they could do was stand at the edge and look down on it.

As a result, the estimate of $1.47 million is an estimate in the truest sense of the word.

“That amount could change dramatically,” Hinton said. “This is really a starting point if you will. We had to come up with an estimate in order to request the funds, so that’s what we did.”

The first order of business now is to hire a geotechnical engineer to do a more thorough assessment. Once work does get underway, Hinton has no guess how long it may take, since the approach hasn’t even been figured out.

Last on the list will be cleaning up debris left along the track of the first slide. The area is steep, wooded and inaccessible, so carting off truckloads of dirt from the slide’s wake may be difficult, Hinton said.

“You would likely create even more of a problem, so the question is ‘Can we stabilize it on site?’” Hinton said. “I think everyone would agree just throwing grass seed on it isn’t going to do it.”

But, it could be possible to recontour the mounds of debris and build some retaining walls that would hold it. Rich Cove Road, which winds up the mountain to Ghost Town, is crossed twice by the slide’s track.

“For a while every time you get a rain, it is going to wash some of that across the road,” Hinton said.

For now, that’s the least of their concerns.

“The main thing is to stop a major movement,” Hinton said.

In the meantime, Hinton does not foresee Ghost Town amusement park opening until the slide is stabilized, although it is not an area his agency has jurisdiction over.

“I don’t see how they could,” Hinton said. “I wouldn’t want a crowd up there on a Saturday and that thing decide to let loose.”

Ghost Town has been struggling with bankruptcy for the past year. Foreclosure against the park is scheduled for June by BB&T, which is owed $9.5 million on the property. However, Ghost Town owners are optimistic that investors or some sort of financing will materialize between now and then. If so, BB&T has said it would call off foreclosure.

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