River cleanup work will continue into December
Cleanup work on the Whitefish River will continue to mid-December, according to the Environmental Protection Agency, with bank stabilization work and sampling continuing after that.
Jennifer Chergo, a spokesperson at the EPA's Region 8 office in Denver, said about 40 percent of the excavation work inside the 500-foot long cofferdam below the BNSF Loop bike path is completed.
The work has been going slower than expected, Chergo said, and excavation will likely continue to mid-December, at which time the cofferdam will be removed. Stream-bank stabilization work after that will be done to prevent erosion during next year's late-spring runoff. Restoration work, with vegetation, would take place next spring and summer, she said.
About 12-18 inches of petroleum-contaminated sediment is being removed from the exposed river bottom, and samples have been taken about every 50 feet and sent to a lab, Chergo said. The contamination seems to be unevenly distributed and is concentrated in areas by river currents, she said.
The EPA will collect river sediment samples downstream from the Second Street bridge this winter to define the extent of the contamination. Examination of the interceptor trench so far shows that it is "functioning as it should," she said.
BNSF Railway installed the trench in 1973 to prevent petroleum from moving underground into the river. The source of the petroleum is Bunker C and diesel fuel spilled during locomotive-fueling operations inside the BNSF railyard above the bike path.
BNSF spokesman Gus Melonas said analysis of the sediments indicates the contamination is decades old. The company will spend about $1 million to $1.5 million this fall removing 1,000 to 2,000 cubic yards of contaminated sediment.
So far, 20 rail cars have been filled, and 14 more cars have been ordered, Melonas said. The sediment is treated with quicklime prior to loading and will be shipped to a special landfill in North Dakota.
David Romero, the EPA's on-scene coordinator, said the plan is to return to the same section of the river in March through May next year, when river flow is still low, and clean up the south half of the river. It's not clear if a cofferdam will be used, he said.
Cleanup work will take place on a 500-foot long section adjacent to the current site and a smaller 100-foot long area on the north side of the river, just upstream from the current cleanup site, where some contamination was located. Next fall, cleanup work will continue in the upper reach of the river, between the Second Street bridge and the current cleanup site, he said.
Concerned about impacts to the shoreline by the cleanup project, the EPA is looking at alternatives to using a cofferdam, Chergo said. Although details remain to be worked out, the EPA is considering a 'supervac" that could remove sediments by sucking them up a hose, she said.
The 'supervac" and a large crane could be loaded on barges and moved up and down the river between sections blocked by bridges. Access to the river for the heavy equipment would still be needed, but the goal would be to no longer station the heavy crane and other equipment on the shore, Chergo said.
Once the upper-reach cleanup is completed, river cleanup work will continue downstream just past the Second Street bridge on the north side of the river, next to Kay Beller Park, Chergo said.
She categorized the current cleanup site as a "pilot project." The land belongs to BNSF Railway, but downstream riverfront property is private property, and landowners must approve access and vegetation removal, she said.
Chergo said the EPA shares the concerns of Whitefish officials and residents about damage to the shoreline of Whitefish River and emphasized that EPA officials will update city staff and city councilors at regular intervals about future plans.