Sponge parks: the green solution to floods

When water has nowhere to go

Asphalt streets, concrete sidewalks, parking lots: our cities are covered with impermeable surfaces that prevent water from seeping into the ground. Instead, it rushes toward sewer systems, often designed decades ago when extreme rainfall was rare. But with climate change, that’s no longer the case.

In just a few hours, pipes are overwhelmed, and streets turn into rivers. Water ends up where we fear it most—basements of businesses and homes—causing costly property damage.  And guess who pays the price? The entire community.

Trading concrete for green spaces

Rather than endlessly expanding underground networks, we can give water a different place to go, like a sponge park.

Behind its ordinary park appearance lies a smart design: permeable soils, vegetated swales, discreet basins and low-lying areas that temporarily hold water.

How does a sponge park work?

1. Rainwater is captured by the park and directed naturally by the terrain or vegetated channels instead of rushing into sewers.
2. As it passes through vegetation and soil layers, it gets filtered, removing sediments, oils and pollutants.
3. Water is temporarily stored in low-lying areas until the storm passes.
4. It slowly infiltrates the ground, evaporates through plants, or drains gradually into sewers at a controlled pace.

It’s simple: instead of sending everything at once into already saturated pipes, we let nature absorb, filter and release water at its own rhythm.

Why it’s a win for municipalities

For municipalities juggling tight budgets and aging infrastructure, sponge parks check all the right boxes:

• Cost savings: fewer pump trucks and emergency repairs that throw budgets off balance
• Infrastructure protection: less strain on sewers and pumping stations means they last longer
• Peace of mind for residents and business owners: fewer incidents of property damage and better-maintained property values
• Multi-purpose spaces: parks that serve daily needs for leisure, sports and relaxation
• Measurable environmental benefits: reduced urban heat islands, return of biodiversity (birds, pollinators, small wildlife)
• Access to funding: provincial and federal grant programs specifically targeting green infrastructure and climate adaptation
• Strategic positioning: a proactive image of a municipality that anticipates, innovates and adapts

Sponge parks in Quebec

Montreal already has seven sponge parks capable of holding over 2,000,000 litres of water. That’s no small feat!

• Pierre-Dansereau Park (Outremont) – Inaugurated in 2022, it can retain up to 627,000 litres of rainwater. This multi-functional space, both a leisure area and a green engineering project, perfectly illustrates how a park can become an urban resilience infrastructure.
• Howard Park (Villeray–Saint-Michel–Parc-Extension) – Located in a dense neighbourhood, it handles a capacity of 624,000 litres. This project is proof that even modest developments can have a significant impact and inspire other districts.
• Pierre-Bédard Park (Mercier–Hochelaga-Maisonneuve) – Currently under construction, this large-scale project will hold nearly 4,000 m³ of water (4,000,000 litres), with an estimated investment of $16 million. A great example that sponge parks can be implemented on a grand scale.

In Quebec City, the Québec, ville éponge initiative, led by the Conseil régional de l’environnement, is gradually turning the capital into a laboratory for sustainable water management. Rain gardens, vegetated swales and permeable parking lots, like the one on boulevard Père-Lelièvre, help retain water at the source while injecting green into neighbourhoods. A great example of urban planning that combines ecology and quality of life.

And the movement is spreading: several other municipalities in Quebec are testing or deploying similar solutions, often supported by grants and environmental partnerships.

Why not on your property?

Sponge parks aren’t exclusive to large municipal projects. The same principles can easily be applied on a smaller scale around apartment buildings and condos. With a few simple features like rain gardens, vegetated swales or permeable pavement, you can:

• Reduce basement water infiltration
• Protect parking lots and foundations
• Make your property cooler and more pleasant
• Preserve property value

Plus, many municipalities, backed by provincial programs, offer subsidies for these installations. A great opportunity for property owners and condo associations!

Global inspiration

The sponge park concept is part of a broader movement known as “sponge cities.” Launched in China in 2013, this program integrates green infrastructure on a large scale: swales, rain gardens, green roofs and permeable surfaces.

Studies show these measures reduce surface runoff by 20–30%. In Shanghai, 23 parks combining storm water management and recreational spaces demonstrate how this approach can maximize environmental, economic and social benefits.

This is no longer a niche experiment or passing trend—it’s a global shift backed by measurable results.

From grey to green

Traditional “grey” solutions such as massive pipes, giant sewers or underground concrete reservoirs are expensive to build and maintain, and they’re hitting their limits. The future is a blend of traditional engineering and natural solutions.

Sponge parks create that bridge: they don’t replace existing infrastructure, they complement and relieve it. And honestly, between expanding an underground sewer for millions of dollars and building a beautiful park that does the same job while offering green space to the community, the choice is pretty clear.

Better to work with nature than against it, and create cities where life is good, even when it pours.