Number of Montreal buildings in flood-prone areas has doubled: MMC

Heavy rainfall has caused flooding in Montreal. (Christine Long/CTV News)

The number of buildings located in flood-prone areas has doubled in Greater Montreal, according to maps posted online on Monday by the Montreal Metropolitan Community (MMC) council.

The organization hopes to encourage citizens to participate in public consultations on the issue. Nearly 15,000 buildings in Greater Montreal, including 19,000 housing units, are said to be in flood-prone zones, according to the MMC. 

This is roughly double the number of buildings previously in flood zones, and "it also represents 9.9 billion in property values", said Nicolas Milot, acting director of ecological transition and innovation at the MMC, at a technical briefing for the media last Friday.

Pierrefonds and Vaudreuil-Dorion are examples of cities that would be "heavily impacted" by the new regulations, Milot said.

"Vaudreuil-Dorion was practically our perfect student before, there were no houses in flood zones ... but the new ratings mean that there will be a major expansion in their area."

In Pointe-Calumet, in the Laurentians, almost the entire territory would be considered a flood zone under the new regulations.

Low, moderate, high and very high risk

The maps put online by the CMM on Monday are not final, but they allow users to discover in which risk category a sector or neighbourhood would fall, should there be no change to the flood zone regulations proposed by Quebec last June.

These new regulations, and the new maps, are necessary because of climate change, the increasing frequency of major floods and the associated socio-economic costs.

There are four categories of flood risk in the new regulations: low, moderate, high and very high, and each risk corresponds to a colour on the map.

Forcing the government to address concerns

At the beginning of the summer, the Quebec government launched a public consultation on the new flood zone regulations, which is due to end on Oct. 17.

However, the CMM is criticizing Quebec for launching these consultations too quickly and says the new maps should have been published before the public was consulted.

It was partly for this reason that the MMC decided to post the preliminary maps online on Monday morning.

According to Milot, the MMC's aim is to open up the discussion and encourage the government to "get out of its offices" and "meet the public" to address citizens' concerns.

"There is immense public concern" about the new regulations and "all summer long, mayors were besieged with questions from citizens," but "these elected officials also had a lack of understanding of the situation," added the person in charge of the CMM's flood risk management team.

"I think the government needs to go out and meet the citizens, be there to support the elected representatives of the municipalities who are meeting the population, and explain to them as best it can the effect of the by-law on the territory", he added.

This report by The Canadian Press was first published in French on Sept. 30, 2024.