Construction of the Lavigne retention basin

Last updated April 15, 2021
Reading time: 1 min

Underneath Parc Lefebvre, in Ahuntsic-Cartierville, the new Lavigne retention basin is under construction. Connected to the existing sewage network, it will protect the Des Prairies river from wastewater overflow and keep it clean for recreational use.

Learn all about this project


Phase 2: October 2020 to May 2022

Phase 1: Completed in 2019


In Parc Lefebvre, located at the intersection of Chemin Somerset, Rue Laurin and Rue Cousineau, in Ahuntsic-Cartierville.


To connect this new underground retention basin to the existing sewer network, three conduits totalling almost 1.8 km will be laid in tunnels more than 15 metres below ground. It will then be connected northward to the existing system at Boulevard Gouin and south-west to the North Interceptor. 

The basin will also be connected to the integrated real time interceptor control system (CIDI) at the Jean-R.-Marcotte treatment plant.

Approximate cost of phase 2: $34.3 million.

Funding: this work is subsidized under the Building Canada plan.


The Gouin-Lavigne drainage basin is served by a network of combined sewers. When the Gouin collector reaches its full capacity, water accumulates in the collector up to the level of the Des Prairies River. At that point, untreated wastewater begins to flow into the river. 

This overflow may prevent using the water for recreational activities, and contributes to increasing pollution in the Des Prairies River.

Construction of the Lavigne retention basin will reduce the volume of wastewater discharged to the Des Prairies River. It will also improve the Gouin collector’s protection against sewer backups to the 10-year recurrence level.

Progress of the work and daily impacts

The city is taking steps to minimize the impact of public works projects on your day-to-day life. Read our article to learn about all project progress and the most recent notices sent to area residents.