Authorities in south central Minnesota are on high alert as the century-old Rapidan Dam nears collapse after a structural failure on Monday, causing potential widespread flooding and leading to mandatory evacuations.
The Daily Mail reported that the Rapidan Dam, built in 1910 on the Blue Earth River, sustained significant damage, prompting emergency measures.
The event began unfolding early Monday when the west side of the dam near Mankato started to erode, leading to water cascading over the dam by 10:36 am. This structural failure alarmed local authorities and residents, as the dam is about 90 miles southwest of Minneapolis in a region prone to flooding due to its proximity to the Minnesota River Valley.
By Sunday, debris from higher rainfall had already begun accumulating, signaling potential trouble before the dam's erosion. The dam's failure prompted immediate action from local officials, concerned with the potential fallout on the surrounding areas and infrastructure.
Immediate Evacuations Ordered in Minnesota River Valley
In response to the escalating situation, evacuations were ordered for residents in the low-lying areas of the valley. The possibility of a complete dam failure led Blue Earth County Emergency Management to express uncertainty about the dam's future, stating, "We do not know if it will fail or if it will remain in place."
As Governor Tim Walz pointed out, the structural integrity of the 114-year-old dam has been a longstanding issue, indicating that the questions surrounding the dam had persisted for many years. Given the current crisis, Gov. Walz has taken proactive measures, including mobilizing the National Guard to assist in the ongoing emergency operations.
Widespread Impact on Infrastructure and Electricity
Notably, the failure destroyed an Xcel Energy substation located at the dam, disrupting the electrical service of approximately 600 customers. Further, the substantial flow of water threatens to affect infrastructure such as bridges and roads in the area, prompting ongoing assessments and monitoring by emergency management teams.
As the emergency unfolds, North Mankato City Administrator Kevin McCann offered a reassuring note for his city, suggesting robust defenses against the floodwater, "Even before [the water would] get to this dirt, it’d have to rise four feet... So, we’re well protected."
However, the impacts are not confined to Mankato; flooding threatens to impact an extensive area encompassing approximately 20 cities, including Fairmont, posing significant challenges to emergency response efforts and residents' safety.
Homeland Security and Emergency Management Director Kristi Rollwagen stressed the importance of continued vigilance, "Right now the integrity of the dam is intact, but we will continue to monitor it and be aware of what's going on."
Historical Concerns and Recent Evaluations of Rapidan Dam
The dam's structural concerns have been documented over the years. A 2021 assessment indicated that repairs or a complete replacement of the dam would be costly, with just the planning phase estimated to take at least three years.
the recognized risk, no significant preventative action had been taken since the county began to release its licensure exemption under federal energy laws the previous year, citing the dam's unreliability in providing hydroelectric power.
The National Weather Service has indicated that the river in Mankato could crest just below major flood stage by Tuesday morning, offering a glimmer of hope that the worst-case scenario might be averted. Still, the situation remains fluid, and state and local officials are braced for eventualities.
