Thomson Reservoir Remediation Project to begin in 2024
Jun. 22—CARLTON — The Thomson Reservoir Remediation Project is set to begin in spring 2024 and be complete in fall 2025; however, the Minnesota Pollution Control Agency has issued an
environmental assessment worksheet
open for public comment until July 6.
The project is similar to the Scanlon Reservoir project that was completed in fall 2022, but just on a "much larger scale," according to Remediation Project Leader Steven Schoff.
The MPCA lists the Scanlon Reservoir as having a remedial area of 13.5 acres whereas the Thomson Reservoir's remedial area targets about 69 of the most contaminated acres of the 330 acre reservoir, according to the MPCA.
Access points for the project include private land owned by Minnesota Power, in addition to The Kayak Center, which will remain open for public use.
Tthe projects are focused on reducing dioxins/furans in the sediment that are present as a result of industrial discharges into the St. Louis River before modern environmental regulations were in place, according to the MPCA website.
Officials will take carbon amendment and apply it to the surface of sediment. Schoff said over time, the carbon amendment will work its way to the top six inches of sediment, binding the dioxins in the sediment.
"Bugs that are down there in the sediment — which are basically the beginning of the food chain — would not be able to take up the dioxins ... these bugs are eaten by ... young fish, and obviously young fish are eaten by big fish, the ones that emerge are eaten by birds, so this dioxin goes up the food chain and if we're able to cut this off ... we reduce dioxins in the food chain," he said.
To ensure the project's effectiveness, Schoff said, officials will eventually collect fish to measure whether their efforts are working. He added that it will likely be around five years before measurable effects are actually seen.
The Thomson Reservoir Project is the last of eight projects in the St. Louis River Area of Concern. The MPCA lists it as a $40 million project funded by a Great Lake Legacy Act partnership between the MPCA, the EPA, and a voluntary private party.
The St. Louis River Area of Concern was listed as one of the 43 Great Lakes Areas of Concern in 1987 by the U.S. and Canadian governments.
"They did a ton of sampling of all these sites all over the (St. Louis River Area of Concern) ... so they identified the worst of the worst and those are the ones that went to remediation ... this stuff takes a lot of time."
Learn more about the MPCA's efforts to clean up the Saint Louis River
at the MPCA's website.
