History

The History of the Rapidan Dam began in 1866 when Silas Kenworthy built a water powered flour mill along the western banks of the Blue Earth River at the lower rapids. A 230-foot-long iron bridge set on stone pilings was then constructed over the Blue Earth River at Rapidan Mills in 1878 connecting trade and commerce for miles around. In 1890, a new larger water-powered flour mill with a linseed oil mill and elevator was built in this location.

However, success was short-lived as spring ice damaged the new dam in 1891 and shortly after a fire destroyed the mill. In 1899, a new three story flour mill was built in its place. In 1910, the land was then purchased and turned into a dam for electricity. In 1911, building was completed. When opened, the dam was able to double the power of Mankato’s electric system. In 1970, the dam was offered to Blue Earth County as an environmental corridor of wildlife habitats, recreation areas and nature trails. The dam was then reinforced with concrete. In 2020, the Rapidan power station produced approximately 23 million kilowatt-hours of clean energy in a typical year.

Flood

In late June of last year, emergency management workers gave notice that water was surging over the Rapidan Dam. As water flows peaked, debris plugged parts of the structure and the west abutment of the dam partially failed.

The flooding then became too dangerous for workers to cross safely and clear the debris. Water then continued to erode the west side of the dam taking an entire house with it. The bridge on the Rapidan Dam was also partially damaged and closed to the public. The bridge was roughly 40 years old and later demolished. 

1 Year Later

The destruction of the flood and Rapidan Dam is still felt. A family lost their home and the bridge over the dam has now been destroyed. The bridge was destroyed in late January and students at MSU Mankato are now conducting drone surveys funded by a National Science Foundation grant to document the dam’s failure. There have also now been efforts to remove the dam, but that may take a few years to get set up. The drone surveys will take place until 2026.

Interview With Someone Who Barely Missed The Flood

Right before the flood that took place, Sartell High School teacher Michele Nelson took a trip to the Rapidan Dam a week before the flooding took place to visit her brother.

“The Rapidan Dam store is known for home baked pies, and it was sad to see such a family oriented business get ruined in a matter of days,” Nelson said. “I went to visit my brother two days after the flood and I could barely get to his house due to the water being so high and so many roads being blocked.” 

With the flooding that took place, it seemed to take everything around it except for the actual dam itself. The dam still stands with everything getting taken away around it. Commenting on the dam remaining Michele Nelson said, “Even as old as the dam was, it still held through the flooding. It was the earth that gave way.”

Overall it’s hard to ignore some of the damage that this flood caused, and it will be felt by Blue Earth County for years to come.