Clark Fork River named one of the 10 most endangered rivers in America

The Clark Fork River, which runs more than 300 miles through Montana, has been named one of America’s Most Endangered Rivers by the conservation organization American Rivers, which studies river health and produces the annual list.

It’s not the first time a Montana river has made the list. The Smith River was named in 2018 and 2016; the Middle Fork of the Flathead River was named to the list in 2017, and the Kootenai River made the list in 2013. The Colorado River and Snake River also made the list of most endangered rivers this year.

The Clark Fork got the attention because of a large berm or waste area that lies close to the shuttered Smurfit-Stone paper mill, near Missoula. Nearly 900 acres of settling ponds are separated from the river by an “unpermitted gravel berm.”

“A catastrophic flood, such as one like the Yellowstone River flood of 2022, would likely fully inundate or collapse the berm and pull industrial pollutants into the river and downstream,” American Rivers said, in a release explaining Clark Fork being named.

It also said that because of toxic chemical s and heavy metals that leak into groundwater, fish in the area are considered “too contaminated to safely consume.”

International Paper and WestRock, the owners of the site that has been shuttered since 2010, are financially responsible for the area, and conservation groups have called on the Environmental Protection Agency to put more measures in place to clean up the area.

“The place to start is by cleaning up approximately 140 acres of toxic soil and industrial waste in the unlined sludge ponds and landfills near the Clark Fork River,” American Rivers said. “The EPA has the authority through the Superfund process to order cleanup actions on part of a site to reduce immediate risks to human health and the environment while continuing to investigate pollution problems elsewhere at the site.”

The Montana Department of Environmental Quality pointed to yearly inspections and assessments it does at the site to make sure the berms and the land isn’t posing a threat to the Clark Fork River.

The last inspection was done on April 10, and the report said, “No evidence of river erosion along the CFR berm was observed. No evidence of slumping, heaving, breaching, or collapsing was observed. Very little water was observed in holding ponds, no boils in ponds were observed.”

The state DEQ also said the chance of the berm being breached by flooding was extremely small, less than 5%, according to the data the department provided. In modeling included in the report, it listed major flooding stage at above 12 feet and river modeling done using data from the National Oceanic and Atmospheric Administration shows a less than 5% chance of the water even reaching 9 feet, and none approached the minor flood stage, meaning models forecast by the state and federal government don’t predict major flooding approaching the levels needed to damage the berm or disrupt the site.

The Clark Fork is Montana’s largest river by volume, with headwaters near Butte. It captures water from 28,000 miles of creeks and streams before meeting Idaho’s largest natural lake, Lake Pend Oreille.