Contaminated Scanlon water reservoir selected for cleanup

The project is set to begin in fall 2021.

An area within the Scanlon reservoir, near the Scanlon dam. (Izabel Johnson /

A water reservoir in Scanlon was recently deemed an area of concern as a result of sediment contamination and has been selected for a collaborative environmental cleanup project by the Minnesota Pollution Control Agency (MPCA) and the Environmental Protection Agency’s Great Lakes National Program Office.

The reservoir includes approximately 40 acres and is located downstream of Cloquet, upriver of the Scanlon dam. It has been largely used as a hydroelectric generation station for Minnesota Power since 1923.

According to the project summary , the reservoir was one of 43 areas selected across the Great Lakes for cleanup by the United States Environmental Protection Agency (EPA) and the United States Army Corps of Engineers as an effort to mitigate pollution in the lakes .

A nearby Thomson reservoir was also designated for cleanup through the project.

RELATED: Enzyme shows promise in fighting Twin Ports' freshwater corrosion problems


RELATED: MPCA will fund 38 new electric vehicle charging stations

sediment cleanup sites.jpg

“We know we have a contamination problem,” MPCA contaminated sediment coordinator LaRae Lehto said.

Lehto said the Scanlon reservoir was selected due to a high concentration of dioxin and furan contaminants in the sediment and will serve as a pilot for the cleanup of the Thomson reservoir, which is larger in size.

The contamination is an outcome of a dense history of pollution in the reservoir from nearby mills and factories before water was properly treated, Lehto said. She emphasized that it is not the fault of one company, but rather the result of “legacy pollution.”

“We’re trying to address these environmental issues,” remedial project manager Steve Schoff said. “This is really a big deal.”

The contaminated sediment is being consumed by bugs and microorganisms, leading to pollution of the larger ecosystem spread through the food chain. The contamination is not in the water itself, and does not pose a high threat to humans, according to the project summary and Lehto.


Lehto said possible contamination through the consumption of infected fish is the largest threat posed to humans by the pollutants.

Due to a rocky terrain within the reservoir and Minnesota Power’s ownership over much of the property, the project will employ alternative technology than what is typically used in cleanup projects.

“We are getting creative,” Lehto said.

The crew members, contracted nationally through the USEPA, will spray a thin layer of powder-activated carbon on the surface of the contaminated zones, something Schoff said is fairly new technology.

The wetland areas with higher levels of vegetation will be sprayed with the carbon, Lehto said, while the open water areas will be treated through a mixture of the carbon and sand — the main goal being for the carbon to sink into and mix with the sentiment at the bottom of the river.

The Scanlon dam, pictured on Monday, Jan. 18, is located near the cleanup site, officials said. (Izabel Johnson /

Once the carbon is in place, Lehto said people will “not even know it’s there.”


Lehto added that the project aims to keep public impact to a minimum. While officials may need to restrict access to Scanlon River Park, which will serve as the site for the project, and a nearby service road, they plan to allow public access to the water.

“The people of Minnesota own the waters of Minnesota,” Lehto said.

The crew also plans to use the St. Louis River Trail as an access point, according to Schoff, who said accessing the reservoir has been one of the biggest challenges with the project.

The MPCA and EPA have been working closely with the Army Corps of Engineers, the Fond du Lac Band of Lake Superior Chippewa and Minnesota Power to ensure the project’s success. They plan to keep the work site restricted to the southeast side of the waterway, which is mainly owned by Minnesota Power, and officials are currently reaching out to members of the public affected by the upcoming changes.

According to Lehto and Schoff, Minnesota Power has been helpful and cooperative in allowing access to the area needed for the project.

The project is estimated to cost $5.8 million, with funds coming from both the state and federal levels. Approximately 65% of the cost will be covered by the EPA, with MPCA covering 35% using state bonding dollars.

“We are really excited to get the construction project at Scanlon underway,” Lehto said.

The estimated completion date for the cleanup is Summer 2022.

The St. Louis River, pictured on Monday, Jan. 18, is the largest U.S. river to run into Lake Superior. (Izabel Johnson /

What To Read Next