Published on: 01/21/2023 – 17:25
Every winter, the city of Montreal in Canada receives almost two meters of snow on 250 km² of its territory. In order to get rid of him, a veritable logistics machine is set up, the environmental costs of which are difficult to reduce.
From our correspondent in Montreal,
It’s a spectacle that Montrealers end up paying no attention to. After a snowstorm like last weekend, January 14, 2023, a dense stream of construction vehicles lined up to clear the streets and sidewalks.
“We have a fleet of almost 2,200 machines in the field, little bombers, as they’re called, to clear the sidewalks, excavators on the streets, a kind of combine harvester to collect the snow and throw it into the dumpsters,” he explains. passionate, Philippe Sabourin, administration spokesman for the city of Montreal, drives his car a few days after the storm. On one of the city’s already cleared arterial roads, we cross huge trucks filled with snow, we hear their back-up alarms, their vertical exhaust pipes emit a subtle gray smoke.
A polished ballet
The numbers are staggering. 3,000 employees are requested for snow removal. An average of 65 outings are organized every winter to distribute salt and gravel to prevent falls or skids, collect snow and make the city functional. Each trip means almost 11,000 km of sidewalks and roads to be covered, ie a round trip between Paris and Montreal in a few days. One inch of snow on Montreal territory means one million Canadian dollars spent to make routes safer: the city has a nearly $200 million budget for snow removal, and an average of 190 centimeters of snow falls each year.
Once collected, 75% of the snow is stored to be melted in sealed quarries around the city before being discharged into the sewers. The remaining quarter is connected to the pipes as is. “Until the 1990s, snow was dumped straight into the St. Lawrence River with all the waste and pollutants that entailed. The sewer is a 180° turn that Montrealers aren’t necessarily aware of,” says Philippe Sabourin as he crosses a construction barrier on the banks of the majestic Canadian River.
The Fullum Snowfall is one of 16 sewers in the city. We are just a few hundred meters from downtown Montreal, at the foot of the Jacques Cartier Bridge. Big trucks come and dump their snow straight into two meter diameter holes to reach the pipes. Site manager Marcel Brisson monitors the progress of work with a keen eye: “We have three boreholes that we use one after the other. The more intense the water flow, the more snow can be cleared at once. Logically, when the snow blocks, it is the cold nights when water consumption decreases and it has difficulty melting. » Once dumped, the snow flows with the rest of the water to the unique and gigantic water treatment plant in Montreal. “Cigarette butts, packaging and waste water are removed from the snow. The station can treat 88 cubic meters of water per second, so it is never overloaded in winter,” explains Philippe Sabourin.
environmental damage
Sewerage is a big step forward, but the pollution associated with snow removal is still numerous. Already, the engines of the city’s 2,200 machines run for hours, causing pollution that is difficult to quantify. The city spokesman tries to qualify: “The first problem with reducing air pollution in Montreal is the use of wood stoves. We are optimizing snow removal vehicle routes, and citizens need to be vigilant too: every car parked on our street despite warnings means 5 to 10 minutes of operational waste and just as much additional pollution. »
But the effect is not just atmospheric. Noise and visual pollution are still significant. While waiting for distant truck electrification, Montrealers, who live not far from snow storage quarries, plan to spend up to 300 trucks an hour overnight. “The horns on our machines have recently been modified to be less shrill but still audible. We are aware of the inconvenience, but the snow has to be cleared away, otherwise everything is blocked,” the manager regrets.
Reducing the environmental impact of snow removal in Montreal to zero seems impossible. However, the city says it is working on alternatives. Salt, for example, eats away at infrastructure and cars, pollutes the soil and increases the salinity of the water discharged into the St. Lawrence River. Its use was therefore restricted in 2016. Between 150 and 300 grams per square meter are allowed, but pollution remains high: 150,000 tons of salt are dumped by the city every year. “We’re still trying to replace it: we tried coffee grounds, it smelled nice, but it was ineffective. Beet juice was great for melting the ice, but it was sticky and extremely dirty for users,” sighs Philippe Sabourin.
Montreal’s snow cover issue points to an original sin: Fossil fuels have allowed millions of people to settle in climatically difficult areas. In times of energy transition, the challenges facing Montreal, the quintessential winter city, are far more complex than for cities in temperate zones.