After a recent snowfall, road salt usage has resumed in Calgary following a report from last year indicating that the city’s reliance on sodium chloride contributed to the rupture of its largest water feeder. The city declared a local state of emergency when the Bearspaw south feeder main broke in June 2024, leading to water restrictions. An investigation discovered several likely causes, including microcracking in the protective mortar around the pipe, snapped wires from corrosion cracking, and high chloride levels in the soil.
The report highlighted that elevated soil chloride concentrations were linked to road de-icing activities using sodium chloride. The investigation was conducted by Associated Engineering. According to Chris Hewitt, the city’s manager of mobility maintenance, sodium chloride remains the preferred product for winter road maintenance in Calgary due to its effectiveness and standard use across North America. The city utilizes 40,000 to 50,000 tonnes of road salt annually, with a history of using sodium chloride for over two decades.
Regarding alternatives, the city employs sodium chloride and calcium chloride as road salts, along with “pickle” (sand with a small salt amount) and beet brine (beet extract and salt brine). Beet brine, with lower sodium chloride content, is used for downtown winter maintenance after successful testing, although it is costlier. In comparison, Lincoln, Neb., uses a beet brine solution for all winter road maintenance due to its reduced corrosiveness and environmental benefits.
The City of Calgary is exploring the impact of de-icing materials on buried infrastructure and plans to share findings on potential corrosion mitigation strategies in the coming months. City councillors are considering options for winter road maintenance, including varying sodium chloride concentrations. While some councillors are open to alternatives, they acknowledge the effectiveness and cost-efficiency of sodium chloride. Repairing the Bearspaw south feeder main is estimated at $40 million, with ongoing independent reviews led by Siegfried Kiefer.
Overall, the city is evaluating road salt usage and its effects on infrastructure, seeking to balance effectiveness, cost, and environmental impact in its winter maintenance strategies.