News

No coal ash leak, airport says, as questions mount

The north end of a new retaining wall at Asheville Regional Airport collapsed after heavy rains.

By Bill Moss, Published: December 29, 2014

MILLS RIVER — The calls starting coming early on the morning of Christmas Eve, and they were anything but merry.

Part of a 40-foot retaining wall had collapsed at the far end of the Asheville Regional Airport high above Ferncliff Park Drive. On the south end the wall had buckled. No one knew for sure whether the destabilized situation would get worse. More than 2 inches of rain had fallen since Dec. 22 and rain was still coming down.
"I became aware of it initially through the airport and then found out later through Sierra Nevada that they'd actually spotted the issue earlier that morning," said Andrew Tate, who is president of the Henderson County Partnership for Economic Development and also is a member of the Greater Asheville Regional Airport Authority.
Tate's immediate thought was that a road closure would affect Sierra Nevada and Empire Distributing, both of which use Ferncliff Drive to truck beverages to N.C. 280 and on to I-26. In the end, no road closure was necessary and airport officials insist there was no danger of water pollution from hundreds of tons of coal ash the airport has used as fill for its $65 million runway construction project.

Airport officials, engineers, contractors and the state DOT formulated plans to repair the wall on Monday, said Tina Kinsey, marketing director for the airport.
Kinsey said that state environmental inspectors who examined the site had found nothing more serious than the possibility of silt at the wall's base draining into the French Broad River.
"The wall is stable, and the work to fix the damage will begin this week after the detailed corrective plan is finalized," she said. "Most work is expected to take place behind the wall, and the road will not be impacted."

Meanwhile, the Asheville Citizen-Times reported on Wednesday that authorities had ordered work on the wall stopped in the apparent absence of a building permit.

A conference call at 10 a.m. Wednesday, Dec. 24, included Tate, Mills River Mayor Larry Freeman, the chief DOT engineers for Divisions 13 and 14, airport officials and project contractors and engineers.
"There's a slight possibility that once work gets under way to repair the wall there may have to be some sort of interim or spotty closure to get the equipment in," Tate said.
Tate said he had not received an update from the airport since Christmas Eve, when officials told him about the wall failure and later notified him that the road would remain open.
"We haven't seen an update or a timeline or status or anything like that," he said Monday. "I think most of the people were on site that day. My understanding was that the airport, engineer and contractor were all on site that morning. My guess is they already have a plan and timeline in place" to repair the wall.

'Gold standard' for using coal ash

Tate and Kinsey and several other officials say the wall collapse was unrelated to and did not threaten the thick plastic liners that encase tons of coal ash contractors have used as fill for the new runway project.
"This retaining wall is nowhere near any of the coal ash," Kinsey said. "This is all fill dirt." The coal ash "is encapsulated with very thick plastic, it's rigid and there are several layers and it's heat-welded together. It's almost like a complete encasement. In fact, EPA has actually called this particular method of encapsulating dried coal ash the gold standard. It's above and beyond the environmental requirements."
Bill Lapsley, a civil engineer and newly elected Henderson County commissioner, has done work both for Sierra Nevada and Ferncliff Industrial Park. He watched the wall go up while he was doing engineering work on Ferncliff Drive, which leads to Sierra Nevada and Empire.
"I think the wall was fine," Lapsley said. "It had to be designed by a professional engineer. I watched it go up. I never saw anything from the road that caused me any concern. The contractor must have just not protected it from the rain."
Kinsey had a similar explanation.
"Some water ended up where it was not supposed to be," she said. The failure "was caused by the saturation."
The retaining wall is a design called a "segmented block wall, as compared to poured-in-place," Lapsley said. "They're not really that thick. If you look, they're like 6 inches thick. The key is a tie to each one of those concrete slabs (into the dirt). It's a long strip of steel that goes back into the dirt and there's hundreds of those and you pack the dirt on top of the ribbons."
It's sound engineering, he said, as long as water doesn't pour into the backfill.
"If you don't have good drainage, that dirt, if you get it soaking wet so the groundwater level rises, it can act as a lubricant and start sliding," he said.

After repairing the wall, the contractor will complete the part of the job that Lapsley suggested should already have been done — diverting water so it does not build up behind the wall. If it's not drained away, water builds up behind the wall, exerting a huge amount of pressure.
State Rep. Chuck McGrady, who co-authored the state's tough new regulations requiring Duke Energy to dispose of the coal ash stored in its power plant basins, said after he spent all day making calls he ended up satisfied that no coal ash leaked from the site.
"I understand the DENR folks have been out to look at it, which was the right thing to do," he said. "The fill that was added was a pretty good distance from the retaining wall area. The coal ash was put in different cells and each of them is completely lined several times over. Yes, the retaining wall is in the proximity of the coal ash project but no, the retaining wall doesn't in any way relate to the coal ash that was put there."
"I've heard there were concerns that, 'we see black and gray coming out, why is that?' And I'm told the explanation for that is they use a gray riprap and they also used a fabric that is black."
McGrady said he was not surprised that people were anxious about the retaining wall collapse and drainage problem.
"I was concerned when I first heard where this was occurring," he said. "With a round of telephone calls today — I've talked to Duke, I talked to DENR, talked to the airport people, I talked to the mayor of Mills River — I'm pretty confident that this doesn't relate to coal ash."

Coal ash 'isn't going anywhere'

Like Tate, Lapsley said the coal ash ought not be a concern.
"I watched them put that in," he said. "It's encapsulated in a huge plastic bag. It's a real thick liner just like they use in the new solid waste landfills. It's inside a big bag and it's covered in dirt. It's not going anywhere."
Lapsley said he has no problem with the airport's use of the dried coal ash as fill for the new runway. In a document it filed on Nov. 18 with the state Department of Environment and Natural Resources, Duke Energy said it plans to transport another 867,000 tons of coal ash to the airport as fill for the runway project, which also involves the improvement of 40 acres of land for potential aeronautical development.
"From a structural standpoint it's good material," Lapsley said. "The negative part of it is when the groundwater gets in contact with it there's heavy metals and toxic material encapsulated in that fly ash and if that gets out it can cause pollution."
He said there's no question that the airport officials, its governing board and the engineers are aware that water pollution that reached the French Broad River and the wells that supply water for the Sierra Nevada brewery would be catastrophic.
"Nobody's going to do anything to put that at risk," he said. "You can imagine the millions of dollars of liability there."

Temporary stormwater system failed

Kinsey, the Asheville Regional Airport spokeswoman, said Monday "the airport management, project engineers, the wall manufacturer and the project contractor met this afternoon to determine the best approach to fix the damaged retaining wall located along Ferncliff Park Drive.
"The wall suffered damage on the morning of December 24, after heavy rains. The wall was nearing completion, and the last step in the construction was to replace a temporary storm water system with a permanent system. Before this permanent system was constructed, the heavy rains caused damage to each end of the wall. One end collapsed, and one end buckled. In the area that suffered the most damage, there is soil and construction material visible. The dark soil-looking material visible at the north end of the wall is comprised of soil and crushed quarry stone, and the black geogrid (the material that holds the wall in place) is also visible.
"The NC Department of Environment and Natural Resources also inspected the site today, and noted one area of concern caused by the damaged wall where silt could potentially make its way to the French Broad River. No negative impact was noted, and the area will be fixed by tomorrow."