This story originally appeared on Climate News and is part of Climate Office cooperation.
Minnesota’s 100-year-old Rapidan Dam came into the spotlight at national level last week when its partial failure destroyed the house and prompted the district authorities to demolish the neighboring shopBut it is 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 occurred during days of historic flooding in the Midwest, which resulted in the death of two people and broke records in at least 10 placesunderscores the growing threat that climate change poses to the country’s ageing infrastructure as extreme weather events become 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 20th century — are increasingly stressed by extreme weather, especially in the Midwest. Fifth National Climate Assessmentpublished last year, showed annual precipitation increased by 5 to 15 percent across much of the Midwest in the decade to 2021 compared with the previous decade. There have been about 30 dam failures or near-failures in the Midwest since 2018, the assessment said.
Most American dams are more than 60 years vintage, leading to complications such as sediment buildup. That was the case at Rapidan Dam, about 90 miles southwest of the Twin Cities. Too much sediment caused water to flow around the western side of the dam, 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 “significant” hazard potential while being in “poor” condition. The hazard potential indicates how likely it is that a dam failure would endanger human life or cause property damage, with “significant” indicating moderate risk and “high” indicating high risk.
A database analysis by Inside Climate News found that nearly 4,100 dams nationwide are in impoverished or unsatisfactory condition, posing a potential threat to human life or property. In Minnesota, Wisconsin and Michigan, nearly 200 dams are in impoverished condition, and 13 are in impoverished condition and pose a “high” risk of failure if any of them fail.
“A high-risk dam means that if it were to fail, it would likely result in loss of life or significant property damage,” said Erin McCombs, regional environmental director for American Rivers, a nonprofit that advocates for dam removal. “High-risk and poor-condition dams are disasters waiting to happen that can and should be avoided.”
Of the 13 high-risk dams in Minnesota, Wisconsin and Michigan listed in impoverished condition, eight dam owners who responded to Inside Climate News’ questions said their dams do not pose an immediate threat to the public and are inspected frequently, some weekly. The owners of the remaining five, all in Michigan — Portage Plant Dam, Menasha Dam, Manistique Papers Dam, Cornwall Creek Dam and Little Black River Structure B — did not respond.
Repair, replace or remove?
Many of the country’s decaying dams no longer serve any purpose, such as flood mitigation or generating electricity. As the dams near the end of their useful life and their licenses expire, their owners must decide whether to repair, replace or remove them altogether.
Congress allocated approximately 3 billion dollars in the Infrastructure Investment and Jobs Act, signed into law in 2021, regarding dam projects. Dam repairs can often be too exorbitant for cities and petite towns, especially in the long term. Some owners argue that replacing or removing dams may be the best option and that while it may cost more up front, the savings over time make it worth it.