Rapidan Dam in southern Minnesota experiences partial failure; no plans for mass evacuation
RAPIDAN TOWNSHIP, Minn. — Flooding on the Blue Earth River caused an abutment of the Rapidan Dam to partially fail on Monday morning, and it remains in "imminent failure condition."
On Tuesday morning, Blue Earth County Public Works Director Ryan Thilges said the breach threat has diminished, though officials are still concerned because the dam was built on sandstone bedrock that can further erode.
Thilges says the dam itself was not breached. Instead, he described it as a "partial failure of the west abutment." The structure is intact but water continues to flow around it, eroding the slope and forcing an evacuation of the family home of the owners of the Rapidan Dam Store. Late Tuesday night, most of the iconic home collapsed into the river.
Blue Earth County Sheriff Jeff Wersal said the water level in a "catastrophic event would not be that significant."
If there is a full collapse of the dam, county leaders say the river could rise another 2 feet or so. There is a levee system protecting the city and officials are confident it will hold up.
Officials say the bridges spanning County Roads 33 and 90 are being closely monitored for debris passing downstream and may be closed if needed.
Xcel Energy says it has been fortifying several other facilities downriver with sandbags and barriers to protect them if the dam becomes compromised and reaches the substations.
Hundreds of people were without power on Monday night. Xcel says it restored power to about 600 homes and businesses near the dam around midnight.
The Blue Earth River begins in northern Iowa and meets with the river's west branch in Faribault County in southern Minnesota, according to the Minnesota Pollution Control Agency. From there, it flows 108 miles north past the cities of Blue Earth, Winnebago, and Vernon Center to Mankato, where it enters the Minnesota River.
There are 21 cities in that watershed, of which Mankato and Fairmont are the largest.
The National Inventory of Dams rated the Rapidan Dam in poor condition as of April 2023, classifying its hazard potential as "significant."
The Army Corps of Engineers and the Federal Energy Regulatory Commission are still assessing the damage.