Report names upper Mississippi ‘most endangered’ U.S. river

The annual report cites challenges such as climate change and the loss of natural floodplains

Part of a walking trail beside a river is covered by floodwaters.
Mississippi River floodwaters creep onto walking trails at Harriet Island Regional Park on Saturday in St. Paul.
Christine T. Nguyen | MPR News

A new report has named the upper Mississippi as the most endangered river in the United States.

The nonprofit national advocacy group American Rivers publishes an annual report ranking the 10 rivers in the U.S. that face the biggest threats. In this year's report, the Mississippi River — as it flows through Minnesota, Wisconsin, Iowa, Illinois and Missouri — tops the list.

The iconic river is facing challenges such as climate change and the loss of natural floodplains, said Olivia Dorothy, director of the Upper Mississippi River Basin Program for American Rivers.

Those aren’t new threats, Dorothy said, but they have been driving more frequent flooding along the river in recent years.

"I think what a lot of people didn't really realize is the shift into these longer-duration flood events like what we had in 2019, where flooding lasted for over 100 days on the upper Mississippi River, and longer elsewhere,” she said.

The American Rivers report calls for state and federal governments to develop a coordinated water management plan for the upper Mississippi that would account for climate change, give the river room to flood safely and restore wildlife habitat.

Without an overall flood control plan for the river, the current approach to fighting floods on the upper Mississippi River is “really everyone for themselves,” Dorothy said.

“What this means is that you’ve got a layer of chaos happening in an already chaotic natural disaster when it floods,” she said. “We don’t know where that water is going to go.”

A plan should not only include flood control methods, but also ways to slow down the movement of water on the landscape before it flows into the river, Dorothy said.

The report also counts the Lower Missouri River from Sioux City, Iowa to St. Louis, and the Menominee River in Wisconsin and Michigan on its list of the 10 most endangered U.S. rivers.