The winter of 2014 strained the ability of many American cities to keep highways clear of ice and snow. Morton Salt Inc. reported shipping three times the amount of salt they shipped last winter for pavement use. Blizzards choked traffic as far south as Georgia, where the the Atlantic Journal-Constitution reports the state highway department accused one salt supplier of price-gouging.
The Lansing, Michigan area spent so much on road salt and overtime pay that resources may be limited for road repairs later in the year.
Between October and mid-February, more than fifty inches of snow blanketed the Alle-Kiski Valley in western Pennsylvania, about 23 inches above normal. Retails stores ran out of rock salt for weeks, while some communities were forced to limit their use of reserves. Leechburg, PA road crews salted only intersections.
Like dieters seeking to reduce their sodium intake, communities across the U.S. sought ways to cut the amount of salt used on their roads, or to at least cut the cost.
A late February blizzard allowed a Minnesota State University research team to collect and analyze samples of highway runoff in Mankato. Steve Druschel, associate professor of civil engineering, worked with two students to determine the best times at which to apply ice melting pre-treatments to pavement, as well as the effectiveness of different compounds
Druschel’s team will collect data on products used on roadways, their price, their effectiveness, how many vehicles are needed to apply them, when they are applied in relation to storms, and the number and types of vehicles traveling over pretreated areas. Due to shortages, Druschel says that rock salt, which sells off-season for about eighty dollars a ton, has reached $250 a ton in some places. Magnesium chloride, a liquid substitute for salt, has also proven expensive.
“One thing we’re seeing is that the big trucks squeeze a lot of water out of the snow,” Druschel says. “The different types of traffic affect it differently.”
This spring, the team will use their data, along with weather records and information from the Minnesota Department of Transportation, to determine the most efficient and cost-effective ways to de-ice roads. Druschel also headed a 2010 project for MnDOT that compared the effectiveness of 25 combinations of salts.
While some communities have experimented with cutting salt with products like sugar beet juice or discarded brewery grain, others have tried using a stronger salt solution for better results.
Officials in Ridgefield, Connecticut have expressed concerns about the effect of road salt on their town. About five years ago, Ridgefield’s highway department switched from a salt and sand mixture, to a product consisting of salt treated with a derivative of molasses, according to Public Works Director Peter Hill.
Ridgefield First Selectman Rudy Marconi said the switch was made for financial and environmental reasons.
“Wetlands and sensitive areas along roadways were being negatively impacted by the amount of sand that was being used,” Mr. Marconi said. “Not only were we running into issues with our wetlands being silted in, but we were also paying about $100,000 a year to have to sweep our roads every spring… Salt being biodegradable, it was thought not to have an impact on the wetlands…. Now the concern is we have too much salt going into the wetlands, what happens when that gets into the aquifers, eventually. Will it impact the quality of our drinking water?”
In February, Town Planner Betty Brosius complained of an increase in the typical salt-like deposit on her garage floor, the surface of which was becoming pitted.
“I am interested in learning more about the various substances that are used on the roads, and what the chemical composition of those materials means to the environment,” she said. “If the salt has this effect on the concrete in my garage, then I can’t believe it is healthy for the natural environment and clean water.”
Town Engineer Charles Fisher suspects that the amount of salt used on Ridgefield’s roads this winter – over four thousand tons by mid-February – has eroded concrete curbs and steps.
“We’re having a lot of problems with our concrete… We’re seeing (concrete deterioration) a lot. It may be a function of the amount of salt that’s used — I don’t know,” Mr. Fisher told the Ridgefield Press.
Dr. Michael Dietz, of the University of Connecticut Center for Land Use Education and Research, also expressed concern for the quality of drinking water and the effect on the environment, including the fish that the human population catches and eats. He thinks that the salt is rougher on vehicles as well.
“A lot of the repair shops are complaining they’re seeing a big increase in rotting brake lines due to the switch to all salt, instead of the salt-sand mix,” he said.
Dr. Dietz has organized a university conference at the end of March, on the subject of road salt and the environment.
Averaging fifty inches of snow per winter, Milwaukee, Wisconsin spent over ten million dollars in 2012 on ice and snow management. In 2013, Milwaukee received only 28 inches of snow, but still spent almost $6.5 million, including the use of 44,000 tons of salt.
Seeking alternatives to rock salt, Milwaukee once tried a syrupy product, but discontinued it when residents complained of tracking it indoors. The city later sprayed its rock salt with sugar beet juice to make it last longer, but found the solution clogged trucks.
In December, Milwaukee began a pilot program to save money by treating roads with a mixture of discarded cheese brine and rock salt. The resulting mixture sticks to asphalt more effectively than plain salt, and has the added benefit of reducing waste from the state’s famous dairy industry.
“You want to use provolone or mozzarella… Those have the best salt content. You have to do practically nothing to it,” advises Jeffrey A. Tews, fleet operations manager for Milwaukee’s Department of Public Works.
The pilot program is expected to cost Milwaukee $6500. While it is too soon to count Milwaukee’s savings, Polk County in northwest Wisconsin estimates it saved $40,000 in rock salt expenses in 2009, the year it began using cheese brine in combination with rock salt on its highways.
Milwaukee alderman Tony Zielinski predicts that “if this takes off, if this proves to be a success here, I’m sure that it will be used in cities all over the country.” Zielinski says local governments in other states have asked him about the program.
Wastewater manager Chuck Engdahl of F & A Dairy Products in northwestern Wisconsin says that donating most of his company’s cheese brine to local governments has saved about $20,000 a year in transportation costs.
Once applied, odor has not been an issue, nor has the provolone pavement drawn the attention of rodents. But it brings to mind the immigrant family of mice in the 1986 feature cartoon “An American Tail,” who sang in anticipation of America, where “the streets are paved with cheese.”