The Minnesota Dam That Partially Failed Is One of Nearly 200 Across the Upper Midwest in Similarly ‘Poor’ Condition

ST. PAUL, Minn.—Minnesota’s century-old Rapidan Dam captured the national spotlight last week when its partial failure destroyed a home and prompted county officials to demolish an adjacent store. Yet it’s just one of hundreds of dams across the Upper Midwest in similar or worse condition, according to an analysis of federal data by Inside Climate News.

The incident, which occurred amid days of historic flooding across the Midwest that left two people dead and broke records in at least 10 places, highlights the growing threat climate change poses to the country’s aging infrastructure as extreme weather becomes more common and severe.

State and federal officials have warned for years that the nation’s nearly 92,000 dams—many of them built in the early 1900s—are growing increasingly taxed by extreme weather, especially in the Midwest. The Fifth National Climate Assessment, released last year, found that annual precipitation increased by 5 to 15 percent across much of the Midwest in the decade leading up to 2021, compared to the previous decade. Some 30 dam failures or near failures have occurred across the Midwest since 2018, the assessment said.

Most of America’s dams are more than 60 years old, leading to complications like sediment build up. That was the case with the Rapidan Dam, roughly 90 miles southwest of the Twin Cities. Too much sediment caused the water to flow around the dam’s west side, eroding much of the land.

The National Inventory of Dams, a database managed by the Army Corps of Engineers, classifies the 114-year-old Rapidan as having a “significant” hazard potential while being in “poor” condition. Hazard potential indicates how likely a failure at a dam would threaten human life or cause property damage, with “significant” indicating a moderate risk and “high” indicating a high risk.

Inside Climate News’ analysis of that database found that nearly 4,100 dams nationwide are in poor or unsatisfactory condition while also posing a potential threat to human life or property. In Minnesota, Wisconsin and Michigan, nearly 200 dams are in poor condition, and 13 are in poor condition while also posing a “high” hazard risk if any of them fail.

“A high-hazard dam means in the event of failure it would likely result in the loss of human life or significant property damage,” said Erin McCombs, a regional conservation director for American Rivers, a nonprofit that advocates for dam removal. “Dams that are high hazard and in poor condition are catastrophes waiting to happen that can and should be avoided.”

Of the 13 high-hazard dams in Minnesota, Wisconsin and Michigan listed in poor condition, eight dam owners who responded to questions from Inside Climate News all said their dams posed no immediate danger to the public and were frequently inspected, some weekly. Owners of the other five, all in Michigan—the Portage Plant Dam, Menasha Dam, Manistique Papers Dam, Cornwall Creek Dam and Little Black River Structure B—didn’t respond.

Repair, Replace or Remove?

Many of the nation’s ailing dams no longer serve a purpose, like flood mitigation or electricity generation. As dams approach the end of their lifespans and their licenses expire, their owners must decide to repair them, replace them or remove them entirely.

Congress allocated about $3 billion in the Infrastructure Investment and Jobs Act, signed into law in 2021, for dam-related projects. Repairing a dam can often be too costly for cities and small towns, especially in the long run. Some owners say that replacing or removing the dams can be the best option, and that while it may cost more up front, the savings over time make it worthwhile.

In Minnesota, about 75 dams have been replaced with what’s called rock rapids, a series of rocks or boulders that restrict some of the river’s flow but allow wildlife to more freely pass through. 

Other dams that still serve a purpose, however, are being replaced by new dams, as is the case with the Lake Bronson Dam in northern Minnesota. The ​​Minnesota Department of Natural Resources chose to replace that dam, which remains a major attraction in the region as the centerpiece of Lake Bronson State Park. Construction is expected to begin later this summer.

“The DNR has been working toward replacing the Lake Bronson Dam for more than 10 years,” the agency said in a statement. “The more frequent and extreme rain events caused by climate change are putting more pressure on aging infrastructure of all types.”

In Ypsilanti, Michigan, removal of the Peninsular Paper Dam—known locally as Pen Dam—turned out to be the cheapest option in the long run. “You could repair it now for about a million dollars, that was the estimate at one point. But the ongoing cost to future generations was significant,” said Steve Wilcoxen, an Ypsilanti city council member who has been working to remove Pen Dam for five years.

Ypsilanti has allocated $500,000 and received more than $7 million in state and federal grants that were used for feasibility studies and other planning purposes. Still, Wilcoxen said, removing Pen Dam was the best option. “We couldn’t insure it, so covering the cost in the case of failure was impossible,” he said. “We’re a small town—we don’t have the budget to do something like that.”

Efforts are also underway to remove Michigan’s Trowbridge Dam and Manistique Dam, both of which are in disrepair and at risk of failure, which would threaten wildlife and potentially people. A spokesperson for the Michigan city of Allegan said it plans to remove the Allegan City Dam, but the city is being delayed by cleanup efforts of the Kalamazoo River Superfund site.

Removing dams also comes with environmental benefits, supporters say, including improving biodiversity in the rivers and reducing greenhouse gas emissions. The reservoirs the dams create have been found to be major sources of methane gas and carbon dioxide—the product of dead vegetation and other organic matter like fertilizer decomposing in the water.

In the Upper Midwest, Michigan Stands Out

In May 2020, heavy rain contributed to the collapse of two dams along Michigan’s Tittabawassee River just a day apart from one another, unleashing billions of gallons of water into the cities of Sanford and Midland. The floodwaters tore buildings from their foundations, mutilated roads and bridges and sent thousands of Michigan residents fleeing for their lives.

Some 10,000 residents were evacuated from their homes, with parts of Midland submerged in as much as 9 feet of water. The catastrophes caused at least $175 million in damage, authorities said, destroying an estimated 2,500 properties. Miraculously, nobody died.

When it comes to at-risk dams, Michigan stands out among its Upper Midwest neighbors. Of the 13 high-hazard dams in poor condition identified by ICN’s analysis, 11 are in Michigan. There’s the Portage Plant Dam near Henrietta Station, the Shamrock Lake Dam in Clare, the Allegan City Dam and the Trowbridge Dam in Allegan, the White Cloud Dam in White Cloud, the Menasha Dam in Otsego, the Peninsular Paper Dam in Ypsilanti, the Manistique Paper Dam in Manistique, the Barton Dam in Ann Arbor and the Cornwall Creek Dam and Little Black River dam near Cheboygan.

Minnesota and Wisconsin each have just one dam rated as both high hazard and in poor condition: Minnesota’s Lake Bronson Dam in Lake Bronson and Wisconsin’s Rice Lake Dam in Rice Lake. 

The Biden administration has already made available $733 million from the infrastructure law to states and territories to enhance dam safety and rehabilitate or remove aging dams. But in Michigan, it’s unclear if that money is getting to the projects that need it most. 

Out of the 11 high-risk dams identified in Michigan, one of the five owners interviewed by Inside Climate News reported tapping federal funding. Three others are waiting to see if they will be selected.

Ann Arbor, which owns the Barton Dam, said in a statement that it has applied for low-interest federal loans to help with the millions of dollars in repairs required. “However,” the city said, those “funding sources have seen significant competition for repair of aging dams across Michigan and the U.S.”

High Costs and Other Complications Cause Delays

Michigan’s Department of Natural Resources alerted federal authorities that it planned to decommission and remove the Trowbridge Dam in Allegan 40 years ago. The former hydroelectric dam was no longer useful and its polluted reservoir posed a serious health risk to wildlife downstream and anyone who might get exposed to the toxins should the dam fail.

But to this day, that project has yet to reach the construction phase, said Mark Mills, regional manager for the state DNR’s Wildlife Division.

“EPA told us we couldn’t because the dam impoundment contains contaminated waste—PCBs,” Mills said, referring to a group of highly carcinogenic chemicals known as polychlorinated biphenyls. “So we have been Band-Aiding this thing since 1984 as we wait for the cleanup to occur.”

Trowbridge isn’t alone. More than 80 U.S. dams could potentially spread toxic chemicals if they failed, one investigation found. Several companies along the Kalamazoo River, where Trowbridge is located, have been deemed responsible for the pollution of its reservoir, but those companies went out of business or have resisted working with state and federal authorities leading the cleanup efforts.

When that happens, the federal government takes responsibility through the long-underfunded Superfund Program, resulting in many sites around the country waiting years if not decades to move forward with cleanup.

Mills said the whole process at Trowbridge dam will ultimately cost between $100 million and $200 million, and that businesses that polluted the water have pushed back against taking responsibility. One paper company, the NCR Corp., recently signed a consent decree with the U.S. Environmental Protection Agency, agreeing to spend an estimated $55 million to help clean up the Kalamazoo pollution. But the effort is far from over.

“They’re supposed to start work on the dredging part of it to remove the contaminated waste from the impoundment, from in the water, within the next year,” Mills said. “And so we’re probably still four years out.”

Other dam removal efforts have run into various complications of their own. Michigan’s Pen Dam, for example, encountered shipping delays and price spikes during the pandemic, Wilcoxen said. “It was really hard,” he said. “We had communication problems, supply chain issues, the cost of materials went up.”

Wilcoxen believes Ypsilanti should be able to remove the dam soon, but it will take some additional years to get the river and surrounding land to a place where the city can consider the project complete. “The actual removal, I think we can get through that next year,” he said. “But all the other stuff that goes with that will take a while.”