River cleanup work poses questions
BNSF Railway's environmental consultants dropped off a draft copy of their Whitefish River cleanup work plan at City Hall last week.
The inch-thick technical document, including dozens of maps and figures, was drafted by Kennedy/Jenks Consulting. It covers the cleanup of the river from the Second Street bridge to the northern boundary of the BNSF property. Excavation of petroleum-contaminated sediments will be done by Granite Construction Co.
According to the work plan document, the U.S. Environmental Protection Agency (EPA), which ordered the cleanup, discussed the plan with specialists from several agencies, including the U.S. Fish and Wildlife Service and the Montana Department of Environmental Quality (DEQ).
The consensus among the experts was that other chemicals of potential concern that could be present in the sediments, such as polyaromatic hydrocarbons (PAH) or polychlorinated biphenyls (PCBs), would be addressed by the sediment removal.
The ecological risk caused by any chemicals of potential concern remaining after the cleanup 'should be well below a level that would be considered unacceptable by the scientific and regulatory communities," the work plan states.
In response to a Sept. 10 letter from DEQ suggesting potential human health risks were not being adequately addressed, the work plan calls for BNSF to prepare a human health risk assessment for the sediment. The findings, however, "are expected to substantiate the finding of no unacceptable risk levels," the work plan states.
In the first phase of the river cleanup, a cofferdam will isolate about 36,000 square feet of the river along BNSF's interceptor trench, immediately below the closed portion of the BNSF Loop bike path. The cofferdam will be made of metal sheets driven into the sediment and lined with plastic held in place with sand bags.
An excavator will be used to remove sediments on the river bottom to a depth of about one foot. Sorbent booms, silt curtains and vacuum equipment will be used to capture any contamination that might escape the immediate work area.
The contaminated sediments will be hauled by side-dump trucks to a 30-by-150-foot pad lined with polymer sheeting. After the sediments are allowed to drain and then mixed with quicklime, they will be transported by BNSF rail car to the Gascoyne Landfill in North Dakota.
"The planned removal work will result in minimal deepening, but will not substantially change the river channel geometry," the work plan states. River flow velocity is very low, the plan states, so no scouring or erosion of the native clay soils that make up the river bottom is expected.
Backfilling is not called for in the plan, but "geosynthetic clay liner material" will be used to create a five-foot wide protective barrier in places where contaminated sediments remain on the river bottom or along the stream bank. The protective barrier will "minimize the potential for post-remediation erosion of adjacent sediment into surface water and the sediment removal area," the plan states.
The first phase of the river cleanup, which began Sept. 25 and is expected to be completed by Nov. 30, drew some comments at the Whitefish City Council's Oct. 5 meeting.
Richard Hildner, who attended the EPA's public meeting at the Whitefish Community Center on Sept. 29, said he favors seeing the river cleaned up, but he expressed concerns about a "power struggle" between the EPA and DEQ.
DEQ has up to now headed up the investigation of the BNSF fueling station superfund site, which does not include the river. Saying a "turf war" was emerging between the federal and state agencies, Hildner asked the council to create a liaison position between the EPA and the city.
Councilor Frank Sweeney, who also attended the Sept. 20 meeting, said the DEQ's new project manager for the superfund site was present and made a commitment to get the cleanup process moving. There will be no more delays by DEQ, Sweeney told the council.
Councilor Turner Askew asked about language in the EPA's work plan indicating logs removed during cleanup would be returned during the restoration phase.
Mayor Mike Jenson said an engineer connected with the cleanup told him logs would not be put back in the river. Jenson also said he would favor an update from the EPA about every two weeks, but he wasn't sure he wanted a formal liaison appointed.
Councilor John Muhlfeld, who works as a hydrologist for Whitefish-based River Design Group, had some questions about restoration plans once the coffer dams were removed. He was particularly concerned about impacts to the stream banks.
Jenson said an engineer told him much of the siltation on the river bottom was about 30-40 years old and so there was no need to backfill the work area.