This winter's traffic tie-ups from snowstorms and squalls have generated a loud refrain from metro-area drivers: "More salt!"
But researchers, public works officials, traffic experts and environmentalists are actually looking for ways to use less.
"People think they can have snowfall and not have to reduce their speeds," said Gene Merriam, a former DNR commissioner and now president of the Freshwater Society, which sponsored Thursday's 12th annual Road Salt Symposium in Chanhassen. "We have to change the culture."
About 175 people, many of them road officials in boots and reflective vests, attended the event at the Minnesota Landscape Arboretum. There, they heard about a Minnesota Pollution Control Agency study of 74 metro-area lakes, now in its third year, which has found that 28 of the lakes have excessive levels of chloride, most of it from road salt.
And because salt dissolves but does not degrade, and sinks instead of traveling on, those concentrations are only expected to increase if salt remains the primary de-icer in the metro area and around the state, said Brooke Asleson, project manager of the MPCA's Twin Cities Metro Area Chloride Study.
While salt hasn't compromised drinking-water quality or led to any human illnesses, rising concentrations are likely to disrupt annual water dynamics in lakes, affecting water quality and aquatic life, said Heinz Stefan, a professor of engineering at the University of Minnesota.
As a result, various state and local agencies aren't waiting for further study but are acting now to establish salt concentration standards for water bodies and developing strategies on reducing salt, Asleson said.
But that may not be easy. Northern cities rely on salt to keep roads and sidewalks safe. Last year, for example, the Minnesota Department of Transportation, which has been working to cut back on salt, used 267,860 tons of it and 2,544,466 gallons of salt brine on 12,000 miles of state highways and interstates. Cities and counties that maintain their own roads add to that volume.
Several public works officials at Thursday's event said with a note of pride that they've already found ways to cut down on salt.
Applying it to roads before it snows and using a range of chemicals have helped Waconia's public services department to avoid calling out road crews after some storms in recent years, director Craig Eldred said.
"It's a big thing, trying to protect water," Eldred said, adding that using less salt also saves money.
Although there aren't any legal restrictions on salt use, Eldred said they could be coming. In the meantime, he said, some public education will be needed. Many believe the more salt the better, but that's not true, and the excess simply gets washed into storm sewers, streams and lakes, he said.
Meanwhile, state highway officials are considering asking for a lower winter speed limit on highways. That could reduce collisions with Department of Transportation trucks and plows, said Mark Fischbach, MnDOT's metro clear roads manager. He added that salt is spread most evenly and economically when trucks drive under 35 miles per hour. Lower speeds would also keep fast-moving cars from blowing salt off the road, as they do now, Fischbach said.
Staff writer Josephine Marcotty contributed to this report. Bill McAuliffe • 612-673-7646