A bridge near a Minnesota dam is in danger of collapsing into the Blue Earth River due to heavy rain and flooding. The County Road 9 bridge, located near Mankato, is approximately 40 years old and may fall if the weather doesn’t improve to allow for necessary structural reinforcements.
The Midwest has been hit with heavy rain and flooding, causing water levels in the Blue Earth River to rise significantly and testing the Rapidan Dam’s structural integrity. The dam has already experienced a partial failure, resulting in a nearby house falling into the river and the demolition of a nearby store.
Ryan Thilges, the public works director for Blue Earth County, expressed concerns about the bridge’s stability. The bridge’s piers are piled through sediment and sit on sandstone bedrock, without being driven into the bedrock. The rushing water has washed away some of the sediment, putting the bridge at risk.
Thilges mentioned that the lateral stability of the piling was achieved through sediment impounded in the river basin over time. As the river cuts its elevation and washes away sediment, stability is compromised. The water flow is currently too fast to measure sediment levels in the river or at the pier.
The bridge has been closed since the dam began to overtop, and officials are monitoring it for stability. Emergency mitigation strategies, such as shoring up the west pier with loose stones known as rip rap, have been implemented to prevent further exposure at the base of the pier. Governor Tim Walz expressed concerns about the potential collapse of the bridge and assured locals that it would be rebuilt if necessary.
FEMA recently approved a federal disaster declaration for 22 counties in Minnesota affected by flooding, with state funding allocated to help communities. The Rapidan Dam, constructed in 1910, has been damaged by multiple flooding incidents in recent years. An assessment in April 2023 found the dam to be in poor condition, prompting officials to consider the possibility of removal.
In conclusion, the situation with the bridge near the Rapidan Dam remains precarious, with officials closely monitoring its stability. The support from FEMA and the state will aid in recovery efforts for affected communities. The future of the dam and potential reconstruction of the bridge are key considerations as the region grapples with the aftermath of heavy rain and flooding.