Montreal to construct more parks, 'sponge' roads to withstand rain

The City of Montreal will be creating almost 30 parks and 400 "sponge" pavements over the next two years, and a "sponge street" pilot project will be presented next week, in order to adapt the city to heavy rainfall.

The Plante administration made the announcement a few hours before the start of the Adaptation Futures international conference on adaptation to climate change, which opens on Tuesday at the Palais des congrès de Montréal.

Since 2022, the City of Montreal says it has created seven sponge parks and 800 sponge pavements, and according to Mayor Valérie Plante, these green infrastructures "can support the equivalent of two Olympic-sized swimming pools."

Sponge pavements are essentially vegetated projections that absorb rainwater. The city will be adding 30 parks and 400 pavements of this kind in 2024 and 2025 in order to slow down the amount of water that runs into the sewage system during heavy rains.

"I'm not telling you that sponge pavements will solve the problems of flooding or water accumulation when there are torrential rains on a scale that we haven't seen before," said Plante, adding that "the idea is to put in place several measures that together will be effective."

For example, added Plante, "the City of Montreal is investing massively in renovating and updating our underground sewer network, but it is also important to support the upper or surface network."

The municipal administration believes that thanks to the sponge pavements and parks, "the impact of heavy rainfall will be reduced by redirecting the water towards the river, complete retention until the sewer system is available, or gradual drainage through the ground."

"From now on, every park built in Montreal will have to meet the 'climate adaptation criterion if its size allows it,'" the mayor said.

Increasingly, torrential rain is overloading Montreal's sewers and putting a strain on the city's infrastructure, as was the case during the torrential rainstorm at the beginning of July.

Demineralizing public spaces or greening urban environments to allow natural spaces to absorb rainwater is recognized as an effective measure for adapting to climate change.

• READ MORE: Water management to cost Montreal billions as city seeks public's input

SPONGY STREETS

At the end of September, before the Conseil des relations internationales de Montréal, Plante also raised the idea of creating "sponge streets" by, for example, removing asphalt and, in some cases, parking spaces.

On Tuesday, she indicated that a pilot project would soon be presented for the Ville-Marie borough, in an area "where people are repeatedly flooded."

"We know that in the Centre-Sud, in Ville-Marie, it's at the bottom of the hill, so there's a lot of water that accumulates, that comes from above, so we're thinking about how to adapt our territory," she said. "Next week, I promise, I'll give you more details. We'll show you what it's going to look like in terms of landscaping and surfacing."

The Plante administration has pledged to set aside 10-15 per cent of its three-year capital expenditure programme (PTI) for green infrastructure.

More than 1,500 international climate change adaptation specialists are meeting this week at the 'Adaptation Futures' conference to discuss best practices for responding to the challenges posed by climate change.   

-- This report by The Canadian Press was first published in French on Oct. 3, 2023.