Channel management in the LeSueur River
The LeSueur River has been identified as one of the leading contributors of sediment to the Minnesota River. A majority of this sediment has been determined to come from the banks, bluffs and ravines located along the river. This project focuses on a one mile reach of the LeSueur River where stream channel migration and mass wasting are significantly eroding four bluffs. Two township roads and many houses are in danger of falling into the river. Instead of stabilizing the bluffs with rock, the stream channel will be improved to efficiently transport sediment, and natural materials will be used to establish a floodplain bench to protect the toe of the bluffs and provide additional fisheries habitat.
Traditional stone armoring would cost $433,000 to fix just one of the bluffs. This method will fix four bluffs and cost $246,750. The lower cost along with its natural use of materials makes this an attractive alternative. This project will save 4,811 tons of soil per year from entering into the river once
Construction of this project was scheduled to coincide with lower river flows in fall 2010. However, heavy September rains caused massive flooding, and the project area was declared a FEMA Flood Disaster. Before the river flows could return back to a workable level, heavy snowfall and ice conditions set in,
causing the project start date to be pushed back until 2011.
A sediment reduction of 4811 tons/yr is estimated with this project.
Four bluffs were stabilized using toe-wood sod mats. Approximately 2,700 linear feet of streambank was protected. It is estimated that this project will save 4,814 tons of soil per year from entering into the LeSueur River.