June 2025: St. Louis River Area of Concern Updates

The St. Louis River (SLR) was designated as one of the 31 Areas of Concern (AOC) on the Great Lakes. It was designated as an AOC under the U.S. – Canada Great Lakes Water Quality Agreement in 1987 because of significant impacts that occurred before modern environmental laws were in place. Following the SLRAOC Remedial Action Plan, state and federal agencies have been implementing management actions to address the legacy impairments. If you look, you can now see the work in progress throughout the SLRAOC: contractors are busy each construction season, plant and animal populations are rebounding, water is cleaner, and lost habitat is being restored.

Continue reading for June St. Louis River Area of Concern project updates.

Photo: A barge is being loaded with an activated carbon amendment to be placed at Thomson Reservoir. Photo credit: MPCA

Thomson Reservoir

Crews are starting the second and last construction season with equipment mobilization. They will begin in-water placement of the activated carbon amendment to remedy legacy dioxin/furan contamination the week of 6/23.

Paddlers: please maintain a safe distance from the construction barges!

For more information, scroll to the Thomson Reservoir portion of the SLRAOC story map here.