MnDoT project to prevent another landslide accident along Red Lake River
CROOKSTON — It’s been nearly 11 years since a riverbank collapsed, dropping about 6 feet overnight along a 250-foot stretch of U.S. Highway 2, the ground falling toward the Red Lake River below.
Seven severely damaged homes and the Country Club Motel eventually were demolished, as the land gradually continued to slide down the hill.
After a series of temporary measures, the Minnesota Department of Transportation is in the initial stages of a $6.4 million project designed to stabilize the creeping slope descent and protect the federal highway from potential collapse as well.
“It’s a unique design-build project,” said Paul Konickson, MnDOT project engineer, which allows for more flexibility, giving designers and builders the ability to adjust according to what they find.
While little visible construction is under way yet, passersby might notice a series of solar panels on the property. They’re inclinometers, solar-powered instruments that measure, among other factors, how much the ground is moving.
Initial measurements have indicated the slide is advancing about 7 inches annually, according to engineers with Nicholson Construction, the Pittsburgh-based project contractor.
Results of the latest measurements, which should be completed by mid-August, will provide a baseline for design and construction, according to Konickson.
The project calls for major excavation along the riverbank, including the construction of a 100-foot-long, 3-foot-wide wall with a foundation about 75 feet deep, in stronger soils along the glacial till.
The wall will be made of sodium bentonite, a clay-cement slurry designed to add strength, yet with the capability to grow and expand when wet.
A massive backhoe with a 100-foot reach will be brought to the site, perhaps in October to build the wall, according to Konickson, who noted that most large-scale backhoes have a reach of about 30 feet.
“That will probably be the most unique work,” he said. “You probably won’t find a backhoe that size anywhere in Minnesota.”
It will cost about $250,000 just to bring the machine to Crookston, according to Pat Kelly, Crookston’s public works director.
The project, which is being paid for by the state, is expected to be completed by fall 2015.
“We hope to get the construction portion done before winter,” Kelly said, leaving site restoration, including tree planting, for next spring and summer.
That timeline could change, Konickson said, depending on how the design-build process progresses.
Nicholson was one of four contractors to submit project bids, with each providing its own design proposal, he said. “Each one came back with a different way to solve the problem.”
They were scored on a combination of cost and proposal evaluation, according to Konickson.