Good weather this fall has allowed California-based Granite Construction Co. to install oil-containment booms, build a 720-foot-long cofferdam along the north bank and construct a haul road from the river's edge. Contaminated sediment is removed and drained, then is taken to the rail yard where it will be further drained, mixed with quicklime and put in rail cars for shipment to a North Dakota disposal facility, Chergo said. Inside the cofferdam, water is treated and siphoned back into the river.
The cleanup area is next to an interceptor trench built in the early 1970s to prevent an underground petroleum plume from migrating from the fueling facility to the river. Chergo said the trench's functionality was investigated several months ago.
"We did not find oil breaching the trench," she said.
Karin Hilding, senior project engineer for the city of Whitefish, has been assigned city oversight of the project, and said the city is waiting for a restoration plan on the project.
"We want to see a revegetation plan," Hilding said. "The main concern is that they get the area stabilized before spring runoff."
Hilding said she walked the cleanup site two days ago with Rob Hagler, a consultant with the Kennedy/Jenks engineering firm hired by BNSF.
"It's weird to look at half the river with no water in it," Hilding said.
As for the sediment, she said it "smells like oil and looks like oil."
Two weeks ago Whitefish City Council members voiced concerns about restoration and erosion-control measures, and wondered how contaminated sediment on the south side of the river will be prevented from migrating into the cleaned area. Hagler noted at that meeting that a membrane-type material would be installed between the two areas.
There's a long history of petroleum pollution at the rail yard and upper stretch of river, but this round of cleanup was prompted by a citizen complaint two years ago of an oily sheen on the river. The EPA investigated and found bunker fuel oil and weathered diesel fuel.
Chergo said the cleanup is on track to be completed by mid-December as planned.
The EPA is requiring the railroad to clean about two miles of the Whitefish River, to JP Road, but cleanup could extend even farther if the agency determines there's a consistent pattern of contamination, Chergo said.