A Minnesota dam is at risk of collapse due to flooding
Jun 25, 2024, 9:46 AM
RAPIDAN TOWNSHIP, Minn. — A dam in southern Minnesota built in the early 1900s is at risk of collapse, as communities across the Upper Midwest deal with major flooding from heavy rains.
The Blue Earth County government announced Rapidan Dam near Mankato was in “imminent failure condition,” in a Monday Facebook post.
“We do not know if it will totally fail or if it will remain in place, however we determined it was necessary to issue this notification to advise downstream residents and the correct regulatory agencies and other local agencies,” the county said.
The dam – which has been in a “state of disrepair,” according to a 2021 study – was still standing Tuesday morning, and the county said there are no current plans for mass evacuations.
A flash flood warning for Rapidan Dam is set to expire at 10:30 a.m. Tuesday, according to the National Weather Service.
Severe flooding has wreaked havoc across the Midwest for several days, leaving at least one person dead in South Dakota and prompting rescue efforts in multiple states.
In Iowa, days of catastrophic flooding and severe storms prompted President Joe Biden to approve a disaster declaration for some areas, freeing up federal funding for relief efforts.
An evacuation order is in place for two Iowa towns, Rodney and Smithland, due to a levee break on the Little Sioux River, CNN affiliate KCRG reported.
While much of the heavy rain has stopped, flood warnings are still in effect for Mankato, parts of southern Minnesota, South Dakota and Iowa.
In Minnesota, Blue Earth County officials were first notified of “accumulating debris” at the dam Sunday. Workers from Blue Earth County Public Works, the emergency management agency, and the sheriff’s office are actively monitoring the dam, according to the Facebook post.
The Blue Earth River has cut around the west side of the dam, emergency management said, carrying damaging debris in its wake and causing power outages.
In a Monday evening update, the county noted that although there was a “partial failure on the west abutment,” the “dam is still intact.”
“Our agencies are in close contact with Blue Earth County and other local officials regarding the Rapidan Dam near Mankato,” Gov. Tim Walz said in a statement Monday. “Emergency management is on the ground and acting quickly to ensure the safety of Minnesotans as the situation develops.”
The dam, which was completed in 1910, is owned by the county and is capable of generating 6 million watts of hydroelectric power. It’s about 70 miles southwest of Minneapolis.
Dams can break for a number of reasons, including overtopping due to flooding and structural failure, according to FEMA.
A 2021 report from Blue Earth County noted that regular flooding over the years, along with the “toll of time,” have caused significant damage to the dam. The report identified two solutions: repair or remove the dam. The county noted that both options have significant costs.
