Manage underground infrastructure

The city’s underground system is maintained regularly and systematically. Maintenance work helps us understand the system, particularly the sumps and pipes (from the street to the wastewater treatment plant), and take preventative action as needed. In addition, whenever construction or repair work is performed, underground systems are also upgraded and if necessary, repair or reconstruction work on pipes is carried out. 

Building huge ponds to capture and retain water 

Montréal also has retention structures across the island where hundreds of thousands of cubic metres of water can be collected. These basins limit direct overflows in natural waterways and help reduce the risks of urban flooding and backflow.

These retention structures can be: 

• A body of water
• A basin or lake on the surface
• An underground retention basin made of reinforced concrete, with or without a pumping station
• Oversized sewer mains 

These infrastructures are costly for the community and building them is complex. It can take years, if not more than a decade, for them to be ready for service. 

Redirecting water from the streets to absorbent spaces 

Sponge parks 

The characteristics of a resilient park are very similar to those of any other park except that the resilient park is designed as a depression. This means that the park is built at a lower level than the adjacent streets. During severe thunderstorms and torrential rains, water from nearby streets can be redirected to the park (by the principle of gravity) to relieve the sewer system. 

The slopes of these parks are generally gentle and easy to cross on foot. Water accumulates gradually in the park only during heavy rains. After a rain, when the sewer system discharges, regulators release water into the system, and the park becomes functional again. 

Resilient parks are like multifunctional spaces. They can offer all the same activities found in an urban park. However, its plants and street furniture are specially adapted to be immersed in water at times. 

The principle of the resilient park is based on the idea of choosing to flood a specific space to prevent water from accumulating on the street and flooding buildings.