A dam near Mankato, Minn., saw its west abutment washed away by river water, and a Burlington Northern Santa Fe Railroad bridge—which carries cargo crossing the Big Sioux River between North Sioux City, S.D., and Sioux City, Iowa—partially collapsed on June 24 after more than 24 hours of heavy rain.
The partial dam collapse of the west abutment of the Rapidan Dam north of Mankato, on the Blue Earth River, happened in the morning hours of June 24 as rapid liquefaction of the earthen berm washed it away and damaged a nearby concrete Xcel Energy substation.
