Does coal mining increase flood risk in Eastern Kentucky?

This story is original appeared on Grist and is included in the composition Climate table cooperation.

Appalachian states like Kentucky have a long, turbulent history of coal mining and mountaintop mining, a mining process that uses explosives to clear forests and clear soil to gain access to underlying coal seams. For years, researchers have warned that land deformed by mountaintop removal may be more prone to flooding because of the lack of vegetation to prevent runoff. Without trees to protect the rain and soil to absorb it, the water pools together and takes the least sustainable path—down.

In 2019, two Duke University scientists conducted an analysis of flood-prone communities in the region for Inside Climate News, identifying the most “mining-damaged areas.” That included many of the same Eastern Kentucky communities that saw river levels rise 25 feet in just 24 hours last week.

“The findings suggest that after coal mining ceases, its legacy … may continue to exact a toll on residents who live downstream from the hundreds of mountains that were leveled in the Appalachians to generate electricity,” James wrote. Bruggers of Inside Climate News at the time.

Now, in 2022, these findings seem tragically prescient. From July 25th to July 30th, flash flooding and thunderstorms experienced more than 4 inches of rain per hour in Eastern Kentucky, causing local rivers to rise to historic levels. To date, the flood has claimed at least 37 lives.

Nicolas Segre, director of West Virginia University’s Mountain Hydrology Laboratory, studies the hydrological effects of mountaintop removal and how water moves through the environment. While it’s too early to know how much the area’s mining history contributed to this year’s flooding, he said he considers Appalachia to be “climate zero,” a region based on the coal industry that has contributed to higher global temperatures and more carbon in the atmosphere.

“Whether it was the 2016 flood in West Virginia or the recent flood in Kentucky, there’s more intense precipitation because of warmer temperatures,” Zegre said, “and then that precipitation fell on landscapes that were carved up.”

According to some regional scientists, strip mining is not the only factor in the increase in floods. A 2017 Environmental Science and Technology study looked at how mountaintop mining can actually help store precipitation. When a mountaintop is rocked by explosions, the leftover material is packed into an area known as a valley fill. According to the authors, “produced valley-fill watersheds appear to retain precipitation for significant periods of time.”

The study noted that the material in the valley often contains toxic chemicals and heavy metals from the mining process. These compounds are subsequently washed into streams during heavy rain, a process known as alkali mine drainage. Alkaline mine drainage pollutes as much as 22 percent of all streams in central Appalachia, according to a 2012 study also in Environmental Science and Technology.