Cities mobilize to avoid dumping wastewater into waterways

Many Quebec municipalities are working to adopt new solutions to better control flooding, that is, the backflow that can occur when the amount of water in the sewers is too large, especially during heavy rains. We therefore wish to avoid resorting to the present method, which consists in discharging this excess directly into nature, given the context of increasing weather extremes.

For these cities, the solution includes urban redevelopment, and many ideas in this direction are already being implemented or will be implemented soon.

Currently, Montreal’s sewage system is considered standardized, that is, rainwater is mixed with wastewater before going to the treatment plant or, in the case of heavy rains, from the St. Lawrence River, precisely to avoid flooding.

Plant management built sidewalk edging designed to absorb rainwater. More than 300 of them have been developed so far and the city has set itself a goal of having 9,000 square kilometers of these roofs by 2025.

We need to improve our networkpleads Hervé Logy, director of asset management at the City of Montreal.

We have to get out of the sewers, the system we inherited. This is done through investments in public infrastructure. It is also done with the roofs: all the people who will direct the sloping roofs towards the green roofs around the houses will contribute [à la solution].

Moreover, according to Mr. Logie, about a third of the roofs of Montreal’s buildings are sloped, which allows rainwater to run off onto the green roofs below. There is thus the equivalent of 1,000 hectares of surface, he says, making it possible to prevent rainwater from mixing with sewage.

Laval relies on water storage and more green spaces

Just north of Montreal, in Laval, we’re battling the same kind of problem. Moreover, two weeks ago, the rains were so heavy that the water drained directly into nature for 274 hours.

The Boer administration would soon begin construction of three huge underground cisterns to store rainwater, but it would also tax merchants who owned large plots.

At the moment, we have about 60,000 parking spaces in the city center; By implementing a levy, we’re saying to our large malls: “Make an effort to reduce the area of ​​asphalt surface on your property, come and make your own parking lots.”announced the mayor of Laval, Stéphane Boyer.

Obviously, for them, the benefit is in reducing how much tax they’ll pay, but for the municipality, it’s more about downtown with less concrete and less trees. This will help us control floods.

In addition to Montreal and Laval, Quebec City, Trois-Rivières, and Gatineau are among the Quebec cities where floods were the most numerous.

Nationwide, nearly 4% of the water discharged into waterways last year was not treated.

with information from Marie Isabelle Rochon