GPS: A Salt Solution?

Our winter frenemy, salt.

As winter approaches and the threat of black ice returns, cities once again find themselves facing the age-old question of salt use.

Sure, salt is cheap and effective, and it makes roads safer. But the issue isn’t just costs—it’s also chlorine. The large quantity of chlorine in salt poses risks to infrastructure and the environment. Annual runoff and aerial dispersion widens chlorine’s effects; it can seep into groundwater, affecting water quality in drinking wells and in natural waterways and can also harm sensitive vegetation and aquatic life.

Eliminating salt is not yet an option for most cities. Because it’s more cost-effective than man-made and naturally derived (from corn or sugar beets, for example) alternatives, salt remains a constant budget line item for many Canadian municipalities. According to a 2008 Toronto Star article, Ontario alone spreads around two million tonnes of salt on its roads each winter. Toronto, Canada’s biggest user of road salt, accounts for about 135,000 tonnes of it.

The City of Ottawa is working on a solution—sort of. According to yesterday’s press release, the City has added a Global Positioning System (GPS) and material monitoring technology on each of its salt spreader vehicles, helping to save taxpayers $1 million per year while reducing road salt use by as much as 13,300 tonnes.

Starting this winter, the City will gather real-time data from each salt truck and be able to make adjustments to their operations based on the information collected as well as road and weather conditions.

The City is implementing an automated vehicle location and material monitoring system (AVLMMS) designed by Grey Island Systems. While GPS technology has existed for fleet management for some time, this new system was designed to work with the various vendors of salt control systems to collect data specific to salt use.

“We are the first City to use fleet-wide GPS technology to monitor salt operations in real time,” says John Manconi, general manager of public works. “The real-time data we receive from each vehicle will allow staff to make operational adjustments ensuring that we spread the right amount at the right time and allow us to streamline our service delivery.”

But Ottawa isn’t about to stop using salt altogether. “Salting is our first defence against winter storms,” said Councillor Maria McRae, chair of the transportation committee.

Factor in the cost of the GPS equipment—Grey Island Systems co-founder Brian Boychuk estimates $700-$800 per truck—plus the damage that road salt causes to municipal infrastructure over time, not to mention the environmental risk. Sure, the City is collecting useful data, but is Ottawa really saving taxpayer dollars with this option?

Let’s look at the long term. Indeed, salt-use reduction is a step in the right direction. With this new equipment, Ottawa may start seeing less evidence of chlorine in groundwater. But in the bigger picture, groundwater is affected by so much more than chlorine. Every time there’s a rain event, groundwater becomes the victim of runoff and the many toxins it gathers.

Significant change requires a shift in thinking about stormwater management. If cities focused more on sustainable options such as green space, permeable pavement and bioretention swales, they’d probably observe positive fluctuation in groundwater samples, and they could expand the lifespans of municipal assets and infrastructure such as roads, bridges and sewers.

As a result of these investments, they may even starting seeing a little change in their pocketbooks.