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Q&A: Why did AVL wall fail?

Contractor works on Jan. 9, 2015, to stabilize a 40-foot retaining wall at Asheville Regional Airport that failed on Christmas Eve.

The two highest ranking officials of the Asheville Regional Airport answered questions Jan. 8 and 9 about the Christmas Eve failure of the 40-foot-high retaining wall along Ferncliff Park Drive, the plans to repair the wall and restore wetlands damaged by runoff from the site and the risk if any from tons of coal ash used as construction fill at the airport.


Michael Reisman, the director of development and operations for the airport, addressed the Mills River Town Council on Thursday night and answered questions. Lew Bleiweis, the airport's executive director, updated the Greater Asheville Regional Airport Authority on the retaining wall and environmental violation on Friday. The airport authority includes two Henderson County members — Andrew Tate, president of the Partnership for Economic Development, and Bill Moyer, a former Henderson County commissioner.


Here is a question-and-answer based on the airport managers' comments to both boards.

What caused the wall to collapse?


"The wall was, is and remains a sound design," Reisman said. "There was nothing wrong with the design of the wall. The failure of the wall was not related to the design. It was related to storm drain issues that we had behind the wall before we had the opportunity to get the permanent storm drains in place. The temporary stuff unfortunately failed on us and didn't hold up."

LewBleiweisLew BleiweisWhat is the contractor doing now?

"The initial response ... they are taking some panels down and stabilizing the wall so there's no more hazard," Bleiweis said. "But then they are on hold to do any corrective actions until they get the building permits from the county and move forward with that. At the short term when this happened, there was a 42-inch and a 36-inch drainage pipe that goes under Ferncliff Park Drive that takes the sediment to the retention. Those obviously because of the failure were clogged with silt. Those were unclogged and reopened."

How come there was no construction permit?


"Although the airport had a permit for the variance (and) the permit for construction in a flood area, the contractor failed to get a construction permit to build the wall," Bleiweis said. "They have applied for that and the county has stopped any type of restoration of the wall other than stabilization until the permit's in hand."

What if there's more rain before the wall repair is repaired?


"This past weekend we had a larger rain event than the rain event that actually caused the initial damage and all the temporary measures that the contractor additionally put in place worked and there were no issues" with water behind the wall, Bleiweis said.

MichaelReismanMichael ReismanWhat holds the panels up?

"Every one of those panels is actually attached all the way across the back to a very heavy gauge geogrid system that extends about a hundred feet into the earth behind the wall," Reisman said. "So even though the erosion washed away, even though those panels looked like they shifted and were moving — which they were — they were really never in danger of falling because they were connected on the back by that geogrid system that was being held to the ground by the earth."

When will the wall be repaired?

In six to eight weeks from the time the contactor gets the new panels and gets a construction permit, the airport officials said. It's assumed that will happen by late January. "From an assurance standpoint, this was an unforeseen, unexpected event," Bleiweis said. "Contractors and staff addressed it quickly and transparently. We've been open in communicating with the community and it will be fixed with no concern for a future repeat."

Sierra Nevada Brewing Co. and Empire Distributing use ship Ferncliff Park Drive to ship products. Will repair work affect their transportation?

"Obviously there are some big name tenants," Bleiweis said. "We have communicated with them. There is no intention of shutting the road down completely for the restoration and repair of the wall. There was some lane closures during the soil and silt remediation. That may continue in the future but we've got a promise from the contractor to provide us with 24-hour notice when they do need to do lane closures."

The airport has used tons of coal ash as fill for its $64 million runway and taxiway project and plans to use an additional 867,000 tons as it develops 40 acres of land for aeronautical development in a five-year project. Is the coal ash containment safe?

"It's a valid concern," Reisman told the Mills River council. "The coal ash and the vessel that contains the coal ash on the airport was never in jeopardy of being breached as a result of this. The closest any part of the wall is about ninety to a hundred feet, in that general range. The coal ash is contained within a completely sealed encapsulated heat-welded vessel which quite honestly you'd really have to go out there with a piece of equipment to try to puncture that thing before it would probably tear. ... It's very difficult to get it to move as well. ... The way the system is designed is if there was anything leaching or leaking it would leach or leak down to the bottom and the liner system at the bottom is designed to capture anything like that and carry it into self-contained chamber onsite at the airport."

Will there be landscaping to improve the appearance of the wall or shield the retention ponds?

"There will be some extensive landscaping on either side of Ferncliff Park Drive," Reisman. As part of the road improvements paid for by a state economic development incentive, the NCDOT will do the work. "I've seen the landscape plan. It's actually going to look I think pretty darn nice," Reisman said. "But the state had intentionally held off on putting in the landscaping until after the wall was built."