Rapidan Dam house falls into Blue Earth River, caught on video

Part of the white house that was left teetering over the edge of an eroded bluff along the Blue Earth River at the Rapidan Dam after a partial failure of the dam has now fallen into the river.

Blue Earth County officials say a section of the house collapsed into the river late Tuesday shortly before 10 p.m.

The soil under the home had been washed away by the heavy flow of the river that overlapped and eventually breached the west side of the dam starting Monday morning.

The house had already been evacuated when it fell, leaving no risk to the homeowners.

Timeline of Rapidan Dam emergency

Blue Earth County Public Works and Emergency Management are continuously monitoring the dam. Routine monitoring occurred Saturday, Sunday and remains ongoing.  

On Sunday evening, June 23, the dam exhibited high flows and additional debris, but still displayed adequate capacity. 

Around 1:30 a.m. on Monday, June 24, notice was issued that there was water overlapping the dam. Around 3 a.m., notifications were sent to regulatory agencies per requirements of the dam Emergency Action Plan.

As flows peaked on Monday, there was partial failure of the west abutment, resulted in the washing away of an Xcel Energy substation causing power outages. The term "imminent threat" was used as outlined in the the County’s Emergency Action Plan.

"There is a mistruth out there that people believe if the dam had a catastrophic failure, that a wall of seven-foot water would be coming," explained Blue Earth County Emergency Manager Eric Weller. "The water level in a catastrophic event would not be that significant."

The water is flowing around the west side of the dam and continues to erode slopes on the west side, which led to the loss of the white house on the edge of the river.

Water peaked Monday at 34,800 cubic feet per second and have lowered to 33,000 cubic feet per second as of Tuesday morning.

The County Road 9 bridge remains closed to traffic for public safety. 

Blue Earth County has not issued any mass evacuation plans. 

Wednesday morning June 26 update

According to Blue Earth County, State and Federal partners and contractors have been onsite at the dam since Tuesday night and remain there Wednesday morning assessing the situation. 

"We have seen dramatic changes overnight and this morning as the channel around the west abutment of the dam has continued to cut wider and deeper," the county added in an update message. "There is currently little to no flow through the gates of the dam as the majority of the flow is going around the west side of the dam."  

Waterflow has slowed slightly, but the water is still flowing as a rate that inhibits emergency mitigation strategies. 

The focus has shifted from the dam to the bridge given the recent erosion and the county continues to work with downstream communities as the situation develops.  

Rapidan Dam was in poor condition prior to failure

Federal regulators found the Rapidan Dam to be in poor condition in their recent inspections over the last few years.

It’s 114 years old and like a lot of dams across the country, it is starting to act its age.

Failure wasn’t exactly inevitable, but civil engineers say the typical design life for a dam is 50 years and this one was more than twice as old.

They give Minnesota a C grade for dam conditions, which doesn’t inspire a lot of confidence, but it’s at least better than the national grade of D.

The Rapidan Dam is classified as having a significant hazard potential because a failure would cause plenty of environmental damage, but nobody lives permanently in the area immediately downstream.

People are more likely to die if a high hazard dam gives way and a 2022 analysis found Minnesota had six high hazard dams in unsatisfactory or poor condition.

Blue Earth County Commissioner Kevin Paap told FOX 9 that federal inspectors were back at Rapidan in May, and although they still believed it was in poor condition, they told commissioners there were no major dam safety issues needing immediate action.