An elevated demand for road salt thus far this winter has repercussions for the environment, urban infrastructure and property maintenance budgets. Customary stockpiles have been depleted more rapidly than usual throughout the vast swath of Ontario that relies heavily on road salt for melting ice and improving traction.
“This is probably the worst year in 25 years in terms of the number of snow and ice events we’ve experienced,” says Tony DiGiovanni, executive director of Landscape Ontario, which counts many companies that provide snow removal services among its members. “Now we’re finding that the suppliers don’t have the inventory at the time that it’s needed. They have to get it from other places like Montreal and the United States, which adds to the costs.”
The world’s largest salt mine is located on the eastern shore of Lake Huron in Goderich, Ont., making summertime barge shipments an efficient and preferred way to transport significant volumes of product to the major suppliers that sell to distributors, retailers, municipalities and directly to some contractors. Replenishing inventory is more problematic and costly during the winter season, and commercial customers are at the back of the queue since suppliers’ priority commitment is to Ontario’s Ministry of Transportation and municipalities for highway, road and street maintenance.
Almost every other consequence of the heightened need for road salt — more contaminated runoff, accelerated corrosion of exposed, vulnerable materials and increased carbon emissions due to extra truck traffic — takes a toll. Yet, many property owners and managers see slip-and-fall conditions as a more imminent threat.
“Legal liability is what drives a lot of salt use, particularly since there is no recognized standard on how much to apply for various conditions,” DiGiovanni observes.
Researchers at the University of Waterloo are currently developing guidelines and associated automated measuring and monitoring systems to help owners, managers and contractors implement more sustainable snow and ice control programs and prove their diligence. The project, led by Dr. Liping Fu, a professor in the department of civil and environmental engineering, is sponsored by the Natural Sciences and Engineering Research Council of Canada (NSERC) and private industry groups including Landscape Ontario and the U.S.-based Snow and Ice Management Association. The three-year project has been testing and comparing alternative de-icing products, application forms (liquid versus solid) and quantities in differing winter weather conditions.
“The goal is to find out how much salt we need to achieve a desirable level of service under each specific snow event. How can we improve the effectiveness of maintenance operations, minimize salt usage and reduce costs?” explains Fu, who is also director of the Innovative Transportation System Solutions laboratory at Waterloo. “By the end of this project we will be able to provide some kind of guidelines on best treatment strategies and best application rates.”
Although Fu’s earlier safety-inspired research on road transport in winter conditions was the starting point for this project, his new work dovetails with both environmental and cost concerns. Similarly, the Smart About Salt Council — also headquartered in Waterloo Region and endorsed by Landscape Ontario — is a not-for-profit advocacy and training organization that promotes sustainable management practices and voluntary assessment and certification of public and private properties.
Road salt’s solubility means that storm water ponds and other natural filtering processes do little to halt infiltration into watersheds or any permeable surface. Even during a less arduous winter, measurements at Toronto’s Mimico Creek following one significant storm in January 2011 revealed a chloride concentration of 18,200 milligrams per litre (mg/l).
“We are getting spikes after storms that are pretty close to seawater levels (19,250 mg/l), and it’s staying around in the groundwater and the soil. We are now seeing chloride levels that are high in the summer when it’s not being used in the city,” says Angela Wallace, a bio-monitoring analyst for the Toronto Region Conservation Authority (TRCA). “In a storm water pond, all the metals settle out and stay at the bottom of the pond and you can remove that with a backhoe. Chloride is soluble and flushes from ponds and stays in the system.”
Chloride, in the form of salt, invariably arrives with development. This is causing particular concern about watersheds in burgeoning communities within TRCA’s oversight, which includes urban, suburban, exurban and rural areas stretching northward from Lake Ontario in Toronto to the Oak Ridges Moraine.
“Where sensitive species are still found, we are going to see big problems,” Wallace says. “At the mouths of rivers and streams in the southern part of TRCA’s jurisdiction, any sensitive species are already gone.”
Business sense and principles would seem to automatically place a horticulturalists’ association like Landscape Ontario in line with the road salt reduction philosophy, even if many members also offer snow and ice control services. DiGiovanni foresees that the pending guidelines from Dr. Fu’s research team could provide the basis for a defensible standard that would support and protect contractors and property managers alike.
“Once we have something that can be proved in court, we’ll see a great reduction in salt use because there will be a reduction in liability,” he says.
From a business perspective, this winter’s supply shortages and cost increases are exerting pressure on contractors with “salt inclusive” maintenance contracts. From an environmental perspective, however, such contracts can impose more discipline than the alternative “salt extra” contracts.
“If the contractors are reimbursed for the amount of salt being used, from their point of view, there is no incentive to save salt,” Fu suggests.
Much depends on how property owners and managers assess and prioritize environmental concerns and liability risks. As with any adoption of new practices, consumer behaviour is also a major contributing factor.
“In Manitoba where it’s always so cold that salt doesn’t work anyway, you’ll see a lot of sand and they are driving on snow pack,” DiGiovanni reflects. “Here, it’s a matter of expectations. We just expect more. We expect to see clear pavement everywhere.”
Barbara Carss is the editor of Building Strategies & Sustainability magazine.