Breaking the Ice
Winter maintenance for parking lots and private roadways
Experts agree that there are few alternatives to ordinary salt as a versatile, reliable, and economical aid to winter driving. First tested on roadways in New Hampshire in the 1940s, salt has amassed a stellar record for improving safety and cold-weather mobility. However, casual observation reveals that high concentrations of salt that occur near roadsides due to deicing can lead to several detrimental environmental impacts, and closer study has confirmed that the negative effects can extend much further.
McHenry County, IL, DOT employees calibrate a truck by weighing how much material comes out at each controller setting.
Matching application rates with road surface temperatures can result in big savings.
Connie Fortin, founder of Fortin Consulting, says agencies that have adopted a scientific approach to deicing and anti-icing, sometimes called “sensible salting,” are beginning to realize reductions in the amounts of chlorides used to treat road surfaces, without diminishing safety. Fortin, who provides training and consulting services in salt-reduction strategies for municipalities and agencies in winter safety operations, says the savings can be significant. For example, she says the University of Minnesota, in its first year after employing sensible salting techniques such as calibrating salt spreaders and closely coordinating deicer application rates with road surface temperatures, cut its rock salt use by 40%, and its magnesium chloride use by 50%. In the process, she says, the university saved close to $55,000 in winter maintenance expenses.
Lots of Change Needed
Although winter maintenance activities on roadways and highways account for the largest share of salt that enters the environment, deicing activities on parking lots, private roadways, and even paved walkways also rely heavily on snow and ice removal products containing chlorides.
A Little Less Salt
Martin Tirado, executive director of the Snow and Ice Management Association (SIMA), says his organization has begun to take an interest in the issue. Noting that SIMA approaches winter maintenance from a business perspective rather than from the perspective of an environmental advocate, Tirado observes, “There is over-application and overuse of salt as a deicer in the private market.”
Solutions for Ice
Although intuitively it might seem that heavy loads of salt would accelerate the process of clearing ice from pavement, applying extra salt beyond an optimal amount really does no good. Unlike melting ice through warming, where adding more heat obviously speeds things along, piling on extra salt beyond a certain concentration does nothing to speed up melting. That’s because, technically, salt does not melt ice; instead it prevents cold water from organizing itself into crystals.
Tirado says there is not a great deal of data available today on optimal deicer application rates for treating parking lots, and he says what data are available have primarily been derived from roadway studies.
Before, and After, the Storm
Dean Outhouse heads operations for a company that provides snow and ice removal and winter safety maintenance for a number of properties in eastern New Hampshire, including commercial parking lots, and “zero-tolerance clients” such as liquor stores, district courts, and the state armory. He says over the 14 years he’s been in the business his practices have evolved, changing the way he looks at salt.
Sunny Snowy Colorado
About 12 years ago, Scott Zorno was working as a subcontractor for a small snow removal operation in Denver, CO, that he says didn’t use chemical deicers at all.
Balancing the Costs
Zorno says there are a variety of ways of comparing the costs of various deicing materials, emphasizing that their relative expense depends on how they are used.
Evolving Strategies to Reduce Risk
As with all deicing products, liquid deicers pose some risk of environmental impacts, Zorno says, and he tries to keep the risks to a minimum through a few simple management practices.
Writer David C. Richardson is a frequent contributor to Forester publications.