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After a recent snowfall, the use of road salt has resumed, following last year’s report suggesting Calgary’s reliance on sodium chloride played a role in the rupturing of the city’s largest water feeder.
The city issued a local state of emergency when the Bearspaw south feeder main broke in June 2024, resulting in water restrictions.
A report investigating what caused the incident revealed several likely causes, including microcracking in the protective mortar around the pipe, snapped wires caused by stressed corrosion cracking, and high chloride levels in the soil.
“Elevated soil chloride concentrations are believed to be related to road de-icing activities using sodium chloride,” reads the report.
The investigation was overseen by Associated Engineering.
In the wake of the Bearspaw south feeder main break, Calgarians have many questions about what caused the catastrophe. A third-party investigation revealed it’s complicated, but theorized the city’s road salt and brine de-icing formula might have played a part in the pipe’s demise.
Chris Hewitt, the city’s manager of mobility maintenance, said sodium chloride is still the product of choice for winter road maintenance in Calgary.
“At the moment, the most effective product remains sodium chloride, and that really is the standard de-icing material across North America,” he said.
Hewitt said the city uses 40,000 to 50,000 tonnes of road salt per year.
“We’re talking decades — probably 25, 30 years — we’ve been using the sodium chloride,” he said.
According to the report on last year’s water main break, there was “a dramatic shift in chloride concentrations” between soil sampling data in 2014 and 2024.
Are there alternatives?
The only road salts used by the city are sodium chloride and calcium chloride, which is deployed in colder temperatures.
The city also uses “pickle,” a mixture of sand with a small amount of salt, and beet brine, which is a mixture of beet extract and salt brine.
The city currently uses beet brine, which has slightly lower amounts of sodium chloride, for some of its downtown winter maintenance, following a pilot project to test its use as a de-icing agent. Hewitt called it “effective” but also “more costly.”
South of the border, the city of Lincoln, Neb., uses a beet brine solution for all of its winter road maintenance.
The City of Lincoln’s maintenance operations manager, Tim Byrne, said there’s a higher upfront cost, but it’s worth it for significantly less damage done to infrastructure and the environment.
“It makes our brine bout 75 per cent less corrosive than a brine without those additional additives,” Byrne said.
Councillors want best option for roads
Current city councillors who were in office during last year’s water main break shared their thoughts on the use of road salt with CBC News.
Ward 2 Coun. Jennifer Wyness said the city is studying its options for winter road maintenance, including using different concentrations of sodium chloride.
“Unfortunately, in the climate we operate in, you do need salt to help get us traction and manage snow at different temperature levels,” she said.
Aside from the upfront cost, she said factors like the smell attracting animals to the road might not make beet brine the best choice.
A growing body of research shows road salt contributes to metal corrosion and that it can have a negative impact on ecosystems. Despite successful alternatives, many Canadian cities are still using salt because of its price.
Ward 10 Coun. Andre Chabot said the report’s findings don’t point to “a definitive smoking gun,” and that sodium chloride was only “identified as a potential cause, but it was one of many contributors.”
Chabot said he would be open to using alternatives in places directly adjacent to critical underground infrastructure, but that doing away with road salt entirely is not a viable option.
“It’s been proven to be very effective throughout the city, and very cost-effective as well,” he said.
Ward 13 Coun. Dan McLean said he’s willing to have the city spend more upfront on a less-damaging solution.
“If it’s corrosive and it’s damaging our infrastructure, I don’t care what the cost is,” he said. “We have to look at the long-term implications of using something that could cause a way more expensive cost to the taxpayer.”
September 2024 estimates put costs of repairing the Bearspaw south feeder main at $40 million.
An independent review of the feeder main break, led by former businessman Siegfried Kiefer, is ongoing.
