Dump trucks and backhoes filed into Duke Energy’s Dan River power plant Tuesday as officials worked to plug a leaking storage pond that dumped enough coal ash into the river to fill 20 Olympic swimming pools.
Pond water continued to leak from a 48-inch stormwater pipe that broke Sunday, washing at least 50,000 tons of ash carried by 24 million gallons of water into the Dan. Coal ash contains metals that can be toxic at high concentrations.
Engineers and contractors searched for a permanent way to fix the break before turning their attention to a cleanup.
It’s not clear why the reinforced concrete pipeline broke. Built in the 1960s, it runs beneath the unlined ash pond – the only one of Duke’s 14 North Carolina ash ponds with such a pipe beneath it. A power plant in Indiana also has a pipe under its ash pond.
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While Duke has said no downstream problems have been reported, at least one water customer of the Dan River watershed took immediate steps to protect its water supply from any contamination.
Virginia Beach, Va., cut off all pumping from Lake Gaston, a massive downstream reservoir that straddles the state line. The lake also supplies water to the Virginia cities of Norfolk and Chesapeake.
Tom Leahy, Virginia Beach’s public utilities director, said that while his city’s water is safe, all pumping downstream of the ash “has been discontinued until further notice.”
Initial water samples taken from the river near the power plant found normal readings for dissolved oxygen, pH, and other factors, said the N.C. Department of Environment and natural resources. But results for heavy metals, which are of more concern because they are potentially toxic, won’t be back until Wednesday or Thursday.
John Skvarla, North Carolina’s environment secretary, and Duke said downstream water that is treated by municipalities is safe to drink.
The Dan, which flows through eight North Carolina and eight Virginia counties, is known for its riverside trails and paddling. Tuesday, it was gray as concrete.
In Danville, Va., about 20 river miles downstream, a finger stuck into the murky water disappeared at the first knuckle. Dull white contrails of ash residue flecked the river’s surface.
“It was an issue we had to accommodate,” said Barry Dunkley, water director for the city of 43,000. “It created a lot of turbidity, and it won’t settle out so the filters are doing the work.”
Duke had expected the plume of gray water to be past Danville by Tuesday morning, Dunkley said. It wasn’t. Despite that, Dunkley said the city’s drinking water is safe.
At the power plant, deep fissures formed by the rush of water into the broken pipe cut across the surface of the black ash left in the 27-acre pond.
The reinforced concrete pipe had been in place before the ash pond was expanded and divided into two basins in the 1970s. About 1.2 million tons of ash was in both ponds, making them among the smallest of Duke’s ash ponds. The utility said up to 82,000 tons escaped.
The spill, though significant, is a fraction of the size of the 2008 disaster in Kingston, Tenn, said Dawn Harris-Young, a spokeswoman for the Environmental Protection Agency in Atlanta.
The Dan River leak could involve up to 100,000 cubic yards of ash; 5.4 million cubic yards of ash muck poured out in Kingston.
Engineers don’t know why the pipe broke or, at the moment, how to fix it. A temporary, inflatable bladder that stoppered the pipe was removed so cameras could be inserted inside to view the damage.
“This definitely was unexpected,” said Issa Zarzar, who’s in charge of plant demolition and retirement for Duke. “The break of the reinforced concrete pipe was definitely unexpected.”
The plant, opened in 1949, retired its coal units in 2012.
The pipe, Zarzar said, was covered by 3 feet of dirt with ash above that. The pressure on the pipe did not all come from above, he said, but it would have been distributed around it.
The pipe’s outfall, where it spilled stormwater into the river, was inspected Friday for signs of erosion or instability, he said. A second, 36-inch stormwater pipe also runs under the pond.
Two officials of the Environmental Protection Agency were onsite to oversee the work. Skvarla, the environment secretary, toured the site Tuesday morning with Duke’s North Carolina president, Paul Newton, but they left without speaking to reporters.
Federal officials said Tuesday it’s unclear how big a risk the spill poses for Kerr Lake, one of the Southeast’s largest reservoirs and the first lake below the spill. The Army Corps of Engineers, which manages Kerr, was monitoring the spill from its Wilmington office.
“It’s not clear the ash will reach the reservoir,” said Ann Johnson, public information chief for the office. “It’s kind of early, and Kerr is quite a ways down. We’re monitoring it and we’ll stay on top of it.”
‘Ugly gray’ water
The Dan ran black on Monday before it turned “ugly gray,” said Tiffany Haworth, executive director of the Dan River Basin Association. The 12-year-old group promotes trails, recreation and clean water in the river, whose watershed covers 3,300 square miles.
All that’s in jeopardy now. The group, which has an office in Eden, heard about the ash spill from a mail carrier at noon Monday.
“It is a very, very sad day,” Haworth said.
Donna Lisenby, a Boone-based official of the Waterkeeper Alliance, paddled the Dan River near the power plant Tuesday and said the broken pipeline spewed a dark gray slurry into the river well into Tuesday afternoon.
Kayak paddles dug into the riverbed sank 12-14 inches deep in ash, Lisenby said. She said she expected ash to accumulate in pools in the river as it flowed downstream.
Lisenby said that she saw no dead fish, but also little effort to contain the ash.
“Duke Energy’s coal ash does not belong in the Dan River and they need to get it out,” she said.
Duke said a security guard spotted the breach at about 2 p.m. Sunday. Emergency officials downstream were alerted, it said, just before the N.C. Department of Environment and Natural Resources was called at about 6:30 p.m. Duke sent out a press release about the spill at 4 p.m. Monday.
“Our first priority was to make sure we informed first responders, and we had a host of things to confirm but didn’t have numbers yet,” said Duke spokeswoman Erin Culbert. “Certainly we understand that providing quick information is important, but the first responsibility is not only to be timely but to be accurate.”
There will be a cleanup of the Dan, possibly dredging for ash, Duke officials said, but those plans haven’t been made yet.
Duke said the company hasn’t decided whether to now remove the ash left in the pond. An alternative Duke is still weighing is to cover it with a waterproof cap and leave it in place.
Frank Holleman, senior attorney with the Southern Environmental Law Center, said the accident reinforces the lawsuits filed by environmental groups, including the Charlotte-based Catawba Riverkeeper Foundation, over Duke’s ash.
The accident, he said, “surely makes a case more effectively than any witness, expert or document that it’s intensely irresponsible for Duke to store waste next to a major drinking water source.”
South Carolina’s state-owned Santee Cooper and S.C. Electric & Gas have both agreed in legal settlements to remove ash from their ponds.
Groundwater contamination has been found around all of Duke’s North Carolina ash ponds, at least some of it likely to be naturally occurring. The ponds at Dan River were not remarkable among those contamination cases, Holleman said.
“It’s a failure of Duke’s own mistakes and engineering,” he said, “and we’re in the second day and they don’t know how to fix it.”
Staff writer Michael Gordon contributed