Wisconsin Experiencing Rapid Increase in Dam Failures: Report

The state of Wisconsin has been experiencing a rapid increase in dam failures in recent years, according to a new report.
On Thursday, the Wisconsin Policy Form published a report which found that Wisconsin saw 34 dam failures between 2000 and 2023, the second-highest total in the nation after South Carolina. Over 80 percent of those failures—28 in total—occurred since 2018, with 18 taking place since 2020. The report noted that none of the incidents resulted in any human fatalities.
“Wisconsin is home to more than 4,000 dams spread across all of its 72 counties. They range from massive hydroelectric concrete dams, such as the Prairie du Sac Dam on the Wisconsin River, to small earthen dams that create farm ponds. As these dams age and rain events become more extreme, there is debate about whether some should be improved or removed,” the report said, adding that data makes it “clear that dam failures in Wisconsin also are becoming more frequent…”
The National Inventory of Dams, maintained by the U.S. Army Corps of Engineers, includes 1,004 dams in Wisconsin. These structures range from as small as 6 feet tall (about 2 meters) to the 92-foot (28-meter) Flambeau Dam on the Dairyland Reservoir in Rusk County.
The National Inventory of Dams classifies over 200 of Wisconsin’s dams as having high hazard potential, meaning their failure could likely result in human fatalities. Of the 34 dam failures in the state over the past 23 years, three were classified as high hazard potential, while one was deemed significant hazard potential, where failure could lead to economic loss and environmental damage.
Eighteen were considered low hazard, indicating no expected loss of life and minimal economic or environmental impact. The hazard potential for the remaining dams was undetermined.
Since 2009, every Wisconsin state budget has allocated at least $4 million for dam safety projects, the report said. While the funding has been sufficient to address improvements on the state’s most critical dams, the report cautions that “a changing climate—triggering more frequent and severe extreme rain events—could pose new and greater tests to our dam infrastructure.”
According to the report, among 206 “high hazard potential dams” in Wisconsin, “five were found to be in poor or unsatisfactory condition, according to the most recent data.”
“This amounted to about 2.4 percent of the state’s high hazard dams. This marks an improvement for Wisconsin relative to 2019, when 10.1 percent of the state’s high hazard potential dams were in poor or unsatisfactory condition,” the report said.
“In the years to come, state and local leaders face difficult choices about where to invest in maintaining and improving dams to weather future floods and where to consider removing them altogether from the landscape,” the report concluded.
This article includes reporting from The Associated Press.