These Are America’s Ten Most Endangered Rivers

Mining and flood control projects are the main threats to waterways, according to the new report

South Fork Salmon River
Rafters on the South Fork of the Salmon River in Idaho Wikimedia Commons

The conservation group American Rivers has released its annual report on the 10 most endangered rivers in the United States, and there’s a common theme. Human disturbances such as mining, water pumping and dams are the biggest threats facing our waterways, reports Sarah Gibbens at National Geographic.

As Gibbens points out, the list isn’t a rundown of the most polluted rivers in the U.S., which are usually those that drain agricultural land or industrial areas. Instead, it includes rivers that face immediate threats to their water quality or stream flow that still have a chance to be saved. “The label is for rivers facing a critical decision point in the coming years,” spokesperson for American Rivers Amy Kober tells Gibbens.

At the top of the list is the Big Sunflower River, a tributary of the Mississippi river that flows through the state of Mississippi. A project known as the Yazoo Backwater Area Pumping Plan is among the river’s biggest threats, reports Anna Wolfe of Jackson’s Clarion Ledger. The project is a potentially $220 million endeavor aimed at reducing backwater flooding between the Mississippi and Yazoo Rivers.

The project has been floated around by the U.S. Army Corps of Engineers for decades, Wolfe reports, but critics deride it as irresponsible. American Rivers claims it would drain 200,000 acres of wetlands, but a separate report from the Corps of Engineers suggest it would only impact 67,000 acres.

In 2008, the EPA essentially vetoed the project under the Clean Water Act, denying the permits needed for filling in wetlands. But last year, attempts to push the project through renewed. Support for the pumps is still present in Congress and in the current administration.

At the second slot on the list is another long-simmering project that many thought was dead. The rivers of Bristol Bay in Alaska, including the Nushagak and Kvichak and their tributaries, are home to one of the last and largest wild salmon runs in the world. However, a proposed open pit copper and gold mine at the headwaters of the rivers, called the Pebble Mine, threatens the system. If approved, it would be one of North America’s largest.

According to EPA estimates, construction would destroy 24 miles of streams and 1,200 acres of salmon-supporting wetlands. It would also require the building of new infrastructure, including new roads and gas pipelines, which might encourage more development (and mining) in the region. Because of this, the EPA vetoed the project under the Clean Water Act in 2014. But in January 2018, the EPA reversed that decision and has reopened the permitting process for the Pebble Mine.

Other notables on the list include the Boundary Waters Canoe Area Wilderness, a series of thousands of lakes connected by streams and rivers. At the close of the Obama administration, a proposed copper-nickel sulfide-ore mine project was shelved. But it was given new life by the U.S. Forest Service in January.

The lower Rio Grande along the Texas border rounds out the top four. According to the report, the proposed border wall with Mexico includes a 30 mile section of “levee-border walls” that would cut people and wildlife off from the river and possibly increase erosion. Other sections of the border wall, according to the organization, would fragment habitat and lead to increased flooding.

Other threatened rivers on the list include the South Fork of Idaho’s Salmon River where miners want to reopen old open-pit mines; the Mississippi River Gorge in Minnesota where outdated locks and dams are slowly degrading habitat; the Smith River in Montana, where an open pit copper mine is being proposed; Alaska’s Colville River, which is being looked at for intensive oil development; Illinois’ Middle Fork of the Vermillion River where coal ash threatens water quality; and the Kinnickinnic River in Wisconsin where two outdated dams disrupt one of the last free-flowing rivers in the state.

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