This story originally appeared on Grist and is part of the Climate Desk collaboration.
Appalachian states like Kentucky have a long, turbulent history with coal and mountaintop removal—an extractive mining process that uses explosives to clear forests and scrape soil in order to access underlying coal seams. For years, researchers have warned that land warped by mountaintop removal may be more prone to flooding, due to the resulting lack of vegetation to prevent runoff. Without trees to buffer the rain and soil to soak it up, water pools together and heads for the least resistant path—downhill.
In 2019 a pair of Duke University scientists conducted an analysis of flood-prone communities in the region for Inside Climate News, identifying the most “mining-damaged areas.” These included many of the same Eastern Kentucky communities that saw river levels rise by 25 feet in just 24 hours this past week.
“The findings suggest that long after the coal mining stops, its legacy … could continue to exact a price on residents who live downstream from the hundreds of mountains that have been leveled in Appalachia to produce electricity,” wrote Inside Climate News’ James Bruggers at the time.
Now, in 2022, those findings feel tragically prescient. From July 25 to 30, Eastern Kentucky saw a mixture of flash floods and thunderstorms bringing upwards of 4 inches of rain per hour, swelling local rivers to historic levels. To date, the flooding has claimed at least 37 lives.
Nicolas Zégre, director of West Virginia University’s Mountain Hydrology Laboratory, studies the hydrological impacts of mountaintop removal and how water moves through the environment. While it’s too early to know how much the area’s history of mining contributed to this year’s flooding, he said he thinks of Appalachia as “climate zero,” a region built on the coal industry, which contributed to rising global temperatures and increased carbon in the atmosphere.
“Whether it was the 2016 flood in West Virginia or the recent floods in Kentucky, there’s more intense rainfall due to warmer temperatures,” Zégre said, “and then that rainfall was falling on landscapes that have had their forests removed.”
To some regional scientists, strip mining isn’t the only factor behind increased flooding. A 2017 Environmental Science and Technology study looked at how mountaintop-removal mining might actually help store precipitation. When a mountaintop is rocked by explosions, leftover material is packed into areas known as valley fills. According to the authors, “mined watersheds with valley fills appear to store precipitation for considerable periods of time.”
The study did note that the material in valley fills often contains toxic chemicals and heavy metals resulting from the mining process. These compounds are subsequently washed into streams during heavy rain, a process known as alkaline mine drainage. According to a 2012 study, also from Environmental Science and Technology, alkaline mine drainage has polluted as much as 22 percent of all streams in central Appalachia.