Indiana's coal ash ponds are safe from April's floods, but still pose a risk

Heavy rains this April flooded parts of central and southern Indiana. Fortunately, the Indiana Department of Environmental Management said it didn't receive any reports of damage to the state's coal ash ponds. But many of those ponds are in the floodplain, putting them at greater risk for spills.

Coal ash is the waste leftover from burning coal — which can contain toxic heavy metals like mercury, cadmium and arsenic. Flooding could damage the caps that cover the coal ash ponds, causing the ash to leak out and pollute waterways nearby.

Tracy Branam is a research geologist with the Indiana Geological and Water Survey. He said flooding poses the biggest risk to a coal ash pond that's in direct contact with water — one that doesn't have a cap on top or a liner on the bottom. But Branam said even a coal ash pond that's capped and lined can be at risk.

"The biggest issue then is, are you going to breach the settling pond where they put this stuff and will it — as a sediment load — get into the streams. And that's what you don't want," he said.

Branam said sediment is what killed hundreds of fish and other aquatic life during the 2008 Kingston Fossil Plant spill in Tennessee.

Indra Frank is the coal ash advisor for the Hoosier Environmental Council. She said the best solution is prevention.

"So not storing waste in the floodplain in the first place. And there are several other states that are way ahead of us on that," Frank said.

She said states like the Carolinas, Tennessee and Virginia are disposing of their coal ash on higher ground or sending the ash off to be used in products like cement.

Some utilities also used coal ash as fill on coal plant sites. Activists in northwest Indiana have expressed concern about fill at the Michigan City coal plant in particular — which sits behind a large seawall extending out into Lake Michigan.

Coal ash ponds that are no longer being used — sometimes called "legacy ponds" — were originally exempt from Obama-era coal ash rules. That means some of them don't have caps or liners.

The Biden administration finalized a rule to change that last year. But the current Environmental Protection Agency Administrator Lee Zeldin announced his intent to repeal the rule and possibly extend compliance deadlines for coal plants in the meantime.

Indiana utilities with coal ash ponds are required to inspect them for damage every week and monitor the groundwater at least once a year. The flood waters in April made it unsafe for contractors to do regular monitoring for at least two coal ash sites.
 

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In a statement, Duke Energy Indiana spokesperson Angeline Protogere said the utility increased monitoring at its coal ash ponds in anticipation of the flooding in April.

"All of our closed ash basins are protected from a 100-year flood event and final cover systems are constructed above the 100-year elevation," she said.

AES Indiana said there are "no specific state or federal requirements for additional monitoring during a potential flood event."

"AES Indiana does not have any coal ash ponds that still hold water," the Indianapolis-area utility said.

Branam said utilities might want to add extra monitors for surface and ground water at low spots near coal ash ponds to see how flooding might affect the site.

Rebecca is our energy and environment reporter. Contact her at rthiele@iu.edu or follow her on Twitter at @beckythiele.