Cities are moving to prevent sewage from flowing into waterways

Many Quebec municipalities are working to adopt new solutions to better control overflows, that is, when the amount of water in sewers is too high, backflow can occur, especially during heavy rainfall. We therefore want to avoid resorting to the current practice of releasing this overflow directly into nature, a context of increasingly extreme weather events.

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

Currently, Montreal’s sewer system is integrated, meaning that rainwater meets sewage before going to a treatment plant or, in heavy rains, from the St. Lawrence River, precisely to avoid overflows.

The Plante administration has undertaken the construction of curbs designed to absorb rainwater. More than 300 of them have been developed so far and the city has set its sights on having 9,000 square kilometers of such surfaces by 2025.

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

We need to get out of the sewers we have inherited. This is done with investments in public infrastructure. This is also done with roofs: all people contribute to the sloping roofs, leading to the green surfaces around the houses. [à la solution].

Besides, Mr. According to Loge, one-third of Montreal building roofs are sloped, which allows rainwater to drain to the green surfaces below. Thus, equivalent to 1000 hectares of surface, it is possible to prevent rainwater from mixing with sewage, he said.

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Laval relies on water storage and more greenery

North of Montreal, in Laval, we are struggling with the same kind of problem; For two weeks, the rains fell so abundantly that water was released directly into nature for 274 hours.

The Boer administration will soon begin the construction of three huge underground reservoirs to store rainwater, but it will also tax merchants who own large areas.

Currently, we have around 60,000 parking spaces in the city centre; By implementing the tax, we are saying to our big shopping centers: “Work to reduce the asphalt surface area on your properties, come and make your parking lots green.”Laval Mayor Stéphane Boyer announced.

Obviously, for them, the interest is to reduce the amount of tax they pay, but for the municipality, it’s a little less concrete and a little more wooded downtown. . And that helps us control overflows.

In addition to Montreal and Laval, Quebec City, Trois-Rivières and Gatineau are among the Quebec cities where flooding is most common.

Nationwide, about 4% of water released into waterways last year was untreated.

With information from Marie-Isabelle Rochon