River returned to natural channel near CFAC cleanup site

Efforts to return a portion of the Flathead River at the Columbia Falls Aluminum Co. Superfund Site to its natural channel have been completed.

That’s according to a news release from CFAC, which states endeavors to redirect the river began in 2020 as a two-phase process. The work wrapped up March 19, approximately six weeks ahead of schedule and years before it normally would have been conducted.

In a prepared statement, CFAC Project Manager John Stroiazzo said he is pleased with the work, which was approved ahead of time by the U.S. Environmental Protection Agency and the Montana Department of Environmental Quality.

“It was completed ahead of schedule. This early action is a benefit to the Flathead River and is another example of meeting our commitment. Many thanks to our contractors — locals Sandry Construction, Morrison Maierle and Roux Associates — for a job well done,” he said.

The final leg of the project began in late February and entailed a crew removing a sheet pile wall and riprap bank stabilization that were in place to prevent the river from reaching the polluted South Percolation Ponds area.

THE PONDS were constructed in the 1960s after the aluminum plant’s former owner, ACRO, dammed off the northern channel of the Flathead River. During site operations, the small bodies of water were used to manage and process wastewater and stormwater.

The percolation ponds started to erode after the southern channel of the river was “pinched off” from material deposits moving through the canyon. CFAC installed the sheet pile and riprap in order to protect the pond area until research teams could learn more about the sediments, which were eventually “characterized” in a remedial investigation initiated by CFAC during the first phase of the two-phase project. The study determined the sediments were polluted and needed to be removed — work the news release states was completed in January.

The wall and riprap were removed shortly afterward, enabling the river to return to its natural channel safely. This portion of the work began ahead of site remediation to minimize the sediments migrating into the river in flood conditions.

““The RI [remedial investigation] portion of our work showed this would be necessary as part of the overall remedial efforts,” Stroiazzo said. “We knew the sooner we could address the situation, the better. The environmental agencies agreed and provided approval for us to move forward as an early action.”

THE INVESTIGATION work is not yet complete, the release noted. A draft feasibility study was submitted to the EPA and Montana DEQ for review in October 2020. The final report is expected to be completed by the end of May 2021.

The EPA then will issue a proposed plan to describe its preferred remedy option or “alternative.” At that time, the agency will host a public meeting to discuss the matter and allow stakeholders a chance to comment.

Some opposition regarding other parts of the cleanup plan already has emerged from various stakeholders in recent weeks.

For example, in mid-March the Columbia Falls City Council voted to send a sharply worded letter to the EPA and several elected officials. According to an article by the Hungry Horse News, the council took issue with CFAC’s plan to contain contamination at the defunct plant instead of removing it.

The city has a vested interest in what happens at the site, where groundwater near old landfills and wastewater ponds — including the Southern Percolation Ponds — are polluted with cyanide and fluoride. The concern is the pollution eventually may move from the site into nearby wells and the river.

Reporter Kianna Gardner may be reached at 758-4407 or kgardner@dailyinterlake.com