On our roads and in our river: New salt spray for Edmonton's streets?

At a Community and Public Services Committee meeting last week, the City of Edmonton proposed the introduction of a new anti-icing agent, calcium chloride, in its snow and ice removal strategy. The proposal to spray our roads with a liquid salt brine raises questions about how to balance costs, service priorities, safety, and environmental impacts. Everything we put on our roads also enters our river.The proposal last week to conduct pilot projects this winter was passed unanimously by the Committee and in a few months time, operators will begin spraying the road with calcium chloride in advance of anticipated snowfalls. Whereas sanding (mixed with a lesser amount of salt to prevent the sand from clumping) is implemented on top of snow or ice, calcium chloride prevents the snow from bonding to the pavement so that traffic movement naturally clears the snow to the roadside. The City says this will result in less plowing, sanding and de-icing as well as higher cost efficiency.A concern raised by a rust control company in Ontario (where road salts are ubiquitous) warns that calcium chloride will have "dramatic" consequences for vehicle owners and it is well documented that a variety of salt products can cause the deterioration of various public infrastructure including bridges and even the Eliot Lake Mall that collapsed in 2012. The City proposes mitigating these concerns by mixing the liquid salt spray with a corrosion inhibitor.The environmental impacts of road salts and de-icers are also well-documented and are known to be toxic in aquatic environments. A recent study in April of this year demonstrated that the closer a lake is to a road or parking lot, the higher the threat to water quality. Ecological effects of chlorides are already measurable at levels of 100mg per litre and many water bodies test at levels that are much higher.Balancing the need to clear our roads and protect our river is less than straight forward, partly due to the number of variables associated with a snow and ice removal strategy (see the city's cost-benefit analysis). Although sanding constitutes the greater part of Edmonton's strategy to date, the sand is mixed with a lesser amount of road salt already and to some extent, salt-based de-icing has also been implemented. Furthermore, even with pre-storm anti-icing, some amount of sanding, de-icing, and plowing is sure to continue. The City's upcoming pilot projects are intended to help clarify these matters and fortunately, the City has indicated plans to invite public input before finalizing a new policy in the summer of 2018.Given the adverse ecological impacts, the North Saskatchewan Riverkeeper advocates for the prevention of chloride discharges to our water bodies and is looking to see that the City undertakes a clear analysis of snow and ice removal options and their respective ecological footprints. Indeed, last week's meeting revealed that City councillors are looking for the same information and other City initiatives such as the River for Life strategy advocate changes to the management of our winter roads that will "minimize potential for release of pollutants (notably sand and chlorides)."As we revise Edmonton's snow and ice removal strategies, it is interesting to note that the City's earliest and greatest transportation corridor will continue to retain its cover of snow and ice throughout the winter months and for years to come. It is our river, of course: the heart of our City, an artery that connects one of the largest urban parks in the world, and the life-giving source of our drinking water.For years, the river has been free of snow-plows, but when it comes to calcium chloride and any additives, let's not forget that most things we put on our roads end up in our river too. Reference resources:Summary of Potential Service Improvements to Snow and Ice Control Policy C409I