Bridge Near Minnesota Dam at Risk of Collapse, Officials Helpless

A bridge over the Blue Earth River in southern Minnesota is at risk of crumbling due to the recent partial failure of the Rapidan Dam upriver during last weekend’s flooding.

The Blue Earth River swelled from flooding in late June causing the west abatement of the Rapidan Dam to fail. The rushing water eroded the embankment and prompted concern about the integrity of the County Road 9 bridge downriver.

While the structural integrity of the dam appeared to hold up, there was concern that the 40-year-old bridge could collapse if the weather did not clear up.

Blue County Public Works Director Ryan Thilges said country officials were concerned that there could be either a partial or full collapse of the bridge but it would all depend on “Mother Nature.”

Thilges joined Minnesota Governor Tim Waltz and other state officials who toured the damage to the Rapidan Dam on July 2 and received an update on the flooding and recovery efforts.

Governor Walz said the main concern was that the bridge would be structurally damaged by the flooding. He said officials were questioning whether it would have to be replaced.

The powerful Midwest floods destroyed a Minnesota power station, causing outages for roughly 600 homes.

Water levels reached their peak on July 1, with 34,800 cubic feet of water per second rushing through the dam. The normal flow is only 500 cubic feet per second.

By July 2, the levels began to lower but water continued to erode the west side of the Rapidan Dam

The rushing water washed away significant amounts of sediment which caused the bridge’s supporting piers to become unstable. Workers were able to stabilize one of the supports but were unable to get to the others.

Complicating the issue were the fallen trees that rushed down the river and slammed into the bridge supports, even clinging to the piers.

Thilges said no contractor was willing to send crews into the river to try to push the trees away from the bridge due to safety concerns.