Ash near Lake Norman is risky, neighbors say

Duke Energy's Marshall power plant on Lake Norman.
Duke Energy's Marshall power plant on Lake Norman. dlaird@charlotteobserver.com

A procession of Lake Norman and Charlotte residents beseeched state officials Tuesday to rate North Carolina’s largest ash pond as such an environmental and safety risk that it should be emptied.

The hearing was the last in a string of public meetings on the risks of Duke Energy’s coal ash, determinations that will drive how and when 32 ash ponds are closed.

The pond at the Marshall power plant on Lake Norman holds 16.1 million tons of ash. Another 14.5 million tons of ash is stored at the plant in dry form.

Marshall also sits on the shores of North Carolina’s biggest reservoir and is upstream of Catawba River drinking water intakes that serve 1 million people – facts that nearly three dozen speakers were not about to let the Department of Environmental Quality forget.

Trusting Duke’s studies, which show contaminated groundwater under Marshall’s ash moving toward the lake but not toward neighbors, “is kind of like trusting the (regulators) in Flint,” said Hickory resident Cliff Moone, referring to widespread lead contamination in the Michigan city.

Previous hearings about Duke’s Allen plant in Gaston County and Buck plant in Rowan County focused largely on the many contaminated private wells near them; Duke has denied responsibility. Owners of 35 wells near Marshall got don’t-drink advisories.

Marshall’s neighbors had different concerns.

Many cited the impact to water users downstream, and to property values along Norman’s 520 miles of shoreline, if the ash pond dam failed and contaminants flowed. The Environmental Protection Agency rated the dam in 2014 as a “significant” potential hazard, the third-highest of four ratings.

“I’m not sure if Duke (Energy) has been a good neighbor or a bad neighbor,” said plant neighbor Joel Cherry. “I know they’re an untrusting neighbor at times. … I hope the DEQ will hold Duke’s feet to the fire and clean up Plant Marshall.”

Marshall was among six Duke power plants whose ash ponds the department has labeled as of low-to-intermediate risk as they wait for more data from Duke.

A final determination that Marshall’s pond is of intermediate risk would mean it has to close, by excavating its ash, in 2024. If the state decides risks are low, the pond could stay open until 2029 and Duke would have the option of capping the ash in place.

Groundwater has been contaminated under all 14 of Duke Energy’s active and retired coal-fired power plants in North Carolina. Contaminants at levels above federal or state standards have been found in 33 private and public wells near Marshall, third-highest among Duke’s plants.

Duke says ash isn’t the source, although DEQ has not confirmed that. Tests show that groundwater is not moving toward off-site wells, and boron, a bellwether of coal ash contamination, is confined to areas under the ash itself, Duke has reported.

Environmental advocates are preparing to challenge those conclusions. The state isn’t expected to make the risk classifications final until May.

Amelia Burnette, a lawyer with the Southern Environmental Law Center, said Duke crafted the computer models submitted to DEQ to reduce the apparent extent of contamination at Marshall.

Burnette said the law center’s experts found that Duke assumed, rather than showed, that groundwater is moving only toward the lake. The models also assumed that, once drained, ash in the pond would be dry when in fact most of it would still rest in groundwater, she said.

Duke spokeswoman Erin Culbert disputed both points. The direction of groundwater was established by on-site measurements, not assumptions, she said.

Duke has relied on a national panel of experts to review its submittals to the state, Culbert said, and the industry-supported Electric Power Research Institute validated its models.

Bruce Henderson: 704-358-5051, @bhender