Battered Rapidan bridge has to go before spring floods, county says

Workers are demolishing a bridge in Blue Earth County that was damaged after the partial failure of the nearby Rapidan Dam last year.

The hope is to remove the County Road 9 bridge before “the threat of flooding in the spring,” Ryan Thilges, county engineer and public works director, said Wednesday.

There’s a “significant possibility that the bridge could be critically damaged” in the event of another flood, Thilges said. Water from the second-strongest flood ever recorded at the nearby Rapidan Dam last summer eroded the sandstone bedrock under the bridge.

The flooding made national headlines after causing the dam to partially fail. The west bank of the river flooded over the dam, with erosion pulling in a nearby house and destroying the Rapidan Dam Store, a longtime local business.

A contractor, Hosier Worldwide, began removing the deck of the bridge on Dec. 27, Thilges said. The Deer River-based demolition company built a causeway and plans to divert the flow of the Blue Earth River as they take down the bridge.

Once workers strip the concrete off the bridge’s deck, the plan is to set off small targeted explosions to sever and fell the beams, Thilges said. He said there are plans to have the area cordoned off for public safety and to prevent crowds from gathering to see the blasts.

The demolition is expected to take three months but had a delayed start. The county and Hosier Worldwide are working on a new plan that includes work on weekends, due to a belief that “it is critical to move the project forward in a timely manner,” said a letter sent to residents near the Rapidan Dam on Jan. 6.

The Blue Earth County Board voted in August to replace the bridge and remove the nearby dam. Funding for the $1.16 million demolition comes from a Federal Highway Administration emergency grant. It could be years before the new bridge is completed, Thilges said.