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Lavigne retention basin

The City of Montreal has mandated EBC to carry out Phase 1 work on the Lavigne retention pond project. As part of the overflow monitoring program of the Ministry of Municipal Affairs and Land Occupancy (MAMOT), the city of Montreal is committed to reducing wastewater overflow into the environment under heavy rainfall and has accordingly planned the construction of six basins, including Lavigne. This retention basin is the central element of the overall project, allowing a relay between two supply tunnels and a connection tunnel to the existing collector. With a 42 m diameter and about 25 m depth, the sheer size of this basin is part of its importance to the project. The mandate also calls for other important works, such as excavating for about 2 km of tunnels needed to install 1.8 m pipes and building an access way and two drop structures within the path of the three tunnels, with one well per tunnel. The job includes the open excavation of the Lavigne water retention basin (42 m diameter by 25 m depth), an access way and two drop structures, 1,875 m of tunnelling and the installation of 1,800 mm pipes in the tunnel. The three access structures are concreted, and will have a capacity 30,000 m3 of rainwater.

  • Excavation and construction Lavigne Basin
  • Excavation of 3 other shafts of 7m diameter each including concreting works
  • Excavation of 3 tunnel for a total of 1,875m lenght
  • Installation of 2 km of 1,800 mm piping
  • Connection to the existing Beausejour structure
  • Diversion of an existing sewer and water main on Ranger Street


  • Activity Sector Infrastructures
  • Client Ville de Montréal
  • Year 2017-2019
  • Value $29,500,000
  • Realisation Mode Traditional