Removal of failed Rapidan Dam near Mankato to begin in 2027

Engineers plan to start removal of the Rapidan Dam in 2027, after it failed during major flooding last year.

The process of taking down the dam would continue through 2028, according to a preliminary schedule from Barr Engineering.

The Bloomington-based engineering firm on Tuesday received a $1.47 million contract to draft plans for the removal of the dam, which spans the Blue Earth River west of Mankato. The Blue Earth County Board selected Barr Engineering over one other firm for the contract, which could grow to nearly $2.4 million.

The Rapidan Dam made national headlines last year after flooding caused the dam to partly fail. Last August, the County Board voted to remove the dam rather than fix or replace it. They argued it would cost far more to keep the dam than remove it.

Removal of the Rapidan Dam could cost from $59 million to $75 million, according to an estimate by Barr Engineering in August.

Surveying and mapping at the dam is set to take place throughout 2025, the preliminary schedule from Barr said. A final design is expected in 2026. Abatement and removal of hazardous materials and equipment in the dam’s powerhouse is to take place in 2027 before the dam is removed.