A low-salt diet for the Northland's icy roads?

When the University of Minnesota's sprawling Minneapolis campus cut back on snow and ice-melting chemicals three years ago, some folks worried that accidents would skyrocket.

Salting roads
A Minnesota Department of Transportation salt spreader drops road salt onto the 21st Avenue East on-ramp to Interstate 35 during last Monday's freezing rain. Amanda Hansmeyer /

When the University of Minnesota's sprawling Minneapolis campus cut back on snow and ice-melting chemicals three years ago, some folks worried that accidents would skyrocket.

But despite a 41 percent reduction in salt use and a 99 percent reduction in sand, accidents and injuries on university streets, sidewalks and parking lots didn't go up.

And the Mississippi River is healthier for it.

"We've actually seen an increase in public safety. We've saved money. And it was the right thing to do,'' said Jim Weber, supervisor of the university's Land Care Department.

"Our whole campus is within about 1,000 yards of the river. And everything that goes into the storm sewer goes right down there,'' he said.


State and local regulators and scientists hope the university's model catches on across the state, including in the Northland, where local trout streams could be threatened.

At the main university, salt use was reduced from an average of 775 tons per year to 462 tons annually in recent years. Rather than salting roads and sidewalks only after snow has fallen, U of M crews concentrate on pre-treating surfaces with liquid salt brine before the snow comes down. Called anti-icing, the practice prevents snow from bonding to the concrete or asphalt.

More traditionally, dry salt is applied after the snow starts falling. Not only is that technique less efficient at melting ice, it's also less likely for the salt to stay on the road to do the job. Salt experts say it only takes a few cars to pass over at highway speed before more than half the salt chunks are pushed off the roadway to where they won't do any good.

Also, most salt products don't melt ice very well when temperatures fall below about 15 degrees Fahrenheit, which is when road crews start using sand. But sand has its own problems, clogging storm sewers and stream beds and carrying pollution into local waterways.

Weber said efforts to melt snow and ice by pouring salt on top rarely succeed.

"It's much easier to mechanically remove it after anti-icing with a [shovel or plow] even if it's been packed down,'' he said. "We've saved a lot of hours by going out ahead of an event... and not sending people back out to go over the same stretch again and again trying to melt snow and ice after it forms.''

At the U, once it snows, salt is pre-wetted as it leaves the trucks to help keep it on the road.

Locally, the University of Minnesota Duluth, the Minnesota Department of Transportation and the city of Duluth are scaling back salt use. The agencies use trucks equipped with computerized sensors that show the exact temperature of the pavement, not just the air temperature, so they know what kinds of and how much chemical to use on icy roads.


Those are methods that Carolynn Dindorf, a consultant for the Minnesota Pollution Control Agency, wants to see more of. She and other road salt experts were in Duluth recently to help train private and municipal plow drivers on how to cut back on chemicals and still keep their routes safe.

"We're seeing very good cooperation,'' Dindorf said. "These plow operators take pride in their routes. They want to keep it safe, but they also don't want to pollute the streams they drive by.''

In addition to using less salt, plow operators were told not to push salted snow into wetlands or pile it up near streams. And they were asked to clean up salt spills before warmer temperatures arrive.

But Tom Broadbent, a former Minnesota Department of Transportation plow truck driver who is now an ice control consultant, said attitudes must change, not just among road salt crews, but also the driving public.

"We've created a false expectation that we can have bare pavement right after a snowstorm, or even during a snowstorm. People want to drive as fast in January as they do in July,'' Broadbent told plow drivers at a recent seminar in Duluth.

"Maybe when people know there's an environmental cost, they'll slow down. We can't melt our way to safe roads.''

Salt levels in Chester Creek
News Tribune graphic

John Myers reports on the outdoors, natural resources and the environment for the Duluth News Tribune. You can reach him at
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