River drained for clean-up

The Whitefish River ran dry by noon on Sept. 3 from near the BNSF Railway trestle downstream to the Second Street bridge as the slow-moving river was diverted into three four-foot diameter plastic pipes.

Sandry Construction, the same company that rebuilt Third Street and the 200 block of Central Avenue, is handling the work under the watchful eye of Kennedy/Jenks, the environmental consulting firm BNSF Railway hired to oversee the river clean-up project.

While Sandry turned to the more lucrative railroad work, estimated to be about $3 million, Schellinger Construction will take over the next phase of downtown street work, beginning with two blocks of First Street this fall.

The U.S. Environmental Protection Agency ordered the clean-up after it notified BNSF in March 2009 that the company was responsible for contamination in the river under the Oil Pollution Act. Decades of railroad fueling spills is blamed for the contamination. The EPA wants the river cleaned up over the next few years all the way downstream to the JP Road bridge.

Last year, Granite Con-struction Co. built a 720-foot long coffer dam in the river below the BNSF refueling site, where as much as 110,000 gallons of diesel fuel may remain perched above the river behind a 300-foot long interceptor trench. Contaminated soil on the river bottom was removed after the water behind the coffer dam was pumped out.

This time, Kennedy/Jenks proposed de-watering a larger stretch of river. Tracked equipment will remove up to 18 inches of contaminated sediment from the river bottom. The project began by closing the city's BNSF Loop Trail bike path and setting up chain-link fencing at the low-water mark.

Portable dams made of steel frames and plastic sheeting were erected near the railroad trestle and at the Second Street bridge. Once the large pipes were connected to the dams, the water in between was pumped out to treatment facilities temporarily set up in the BNSF rail yard near the roundhouse.

Contaminated sediment will be pushed into depressions where they will be pumped out as slurry to the treatment facility. The removed sediment will be mixed with lime and loaded into railroad cars for transportation to an approved disposal site.

Restoration plans call for building up the river bottom with round river rock to within 12 inches of the original level and using high-tech sod and fiber roll products to stabilize the river bank for re-vegetating with native plant species.

The plan calls for workers to be on the site from 6 a.m. to 6 p.m. six days a week through Nov. 1 in order to get the work completed before cold weather sets in. Re-vegetating work also will take place this fall.