Path Along Whitefish River Could Remain Closed Into July Because of Oil Sheen

BNSF continues to work in the area in response to an oil sheen spotted on the river last month

By Mike Kordenbrock
A BNSF Railway-led crew investigates an oil sheen on the Whitefish River in Whitefish on April 11, 2023. Hunter D'Antuono | Flathead Beacon.

The closure of a shared use path along the Whitefish River could remain in place into July, as railroad company BNSF continues to work in the area in response to an oil sheen spotted on the river last month near its Whitefish railyard state Superfund site.

An initial closure for the pedestrian and bike pathway between Miles Avenue and Edgewood Place already went into place after crews descended on the area on April 11, but the City of Whitefish recently announced that a closure effective May 22, accompanied by signage and barriers, would be going into place for the same area for approximately six more weeks while construction work continues in an effort to improve an interceptor system and trench in place along the river.

An interceptor trench in the area was installed by BNSF in 1973 to try and prevent contaminants from entering the river, and additional cleanup work, including soil excavation, took place between 2009 and 2013 and again in 2019. 

In a recent announcement, the city described the closure as including an area from the end of the railyard north of the trestle to Miles Avenue. Also included in the closure is the Roundhouse Landing river access, where a boat ramp was removed amid the ongoing response. BNSF has previously characterized the sheen that was discovered on April 10 as small, and the Montana Department of Environmental Quality has said no measurable amount of petroleum was found in the river.

That announcement from the City of Whitefish said BNSF is working with Montana DEQ on the design of an improved interceptor trench, including a deeper trench, intended to prevent low groundwater levels from bypassing the interceptor system that is in place to try and prevent contaminants from entering the river.

The current interceptor trench is oriented to the east and west, and is lined with polyethylene plastic sheeting and backfilled with crushed rock and gravel. Drainage pipes in the trench feed water into a central sump pump that sends water through an oil water separation system. According to DEQ, the work being done to improve the system will involve putting in a second, deeper trench closer to the river on the western side of the existing trench. The new trench will also tie into the existing sump system.

In a progress letter sent to Montana DEQ earlier this month, an environmental engineer with Kennedy/Jenks Consultants who is working on behalf of BNSF, described how the “initial response activities indicate that abnormally low water levels were likely allowing impacted groundwater to go under the trench,” and the letter goes on to state that temporary sump pumps will continue to remove groundwater until a permanent solution can be implemented.

The City of Whitefish similarly described BNSF determining the sheen had been caused by abnormally low groundwater levels “allowing impacted groundwater to pass beneath the existing interceptor trench.”

The additional sump pumps transporting water for treatment in an oil-water separator are just part of the temporary measures put into place so far. A boom containing absorbent materials was also installed along the shoreline near the sheen, as well as a silt fence, and a watertight coffer dam was also put into place to entrap water in the area along the shoreline so it could be drained, and soil could be excavated. Sediments with contamination were found 4 feet deep in a roughly 10-foot-by-8-foot area, according to DEQ. Per the Kennedy/Jenks letter to DEQ, excavated sediment was backfilled with clean, low permeability soils near and at the river, and overlaid with rounded river rocks.

The 78-acre Superfund site has a history of contamination associated with releases from the railyard related to fueling repair, railroad operations and wastewater transportation to lagoons, and the railway’s history of use predates BSNF’s ownership and stretches back to 1903. Chemical substances that have been identified in contaminated soil groundwater associated with the Superfund site include petroleum products, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), volatile organic compounds (VOCS), and heavy metals.