Beauharnois–Les Cèdres hydropower complex includes some 30 structures like dams, dikes and control structures. Built between 1911 and 1971, they still regulate the Fleuve Saint-Laurent (St. Lawrence River), both to allow vessels to navigate the Seaway and to produce hydropower at Les Cèdres and Beauharnois generating stations.

To ensure the long‑term operability of its facilities, Hydro‑Québec is assessing and studying them to determine what work will be required in the future. The modernization project will extend the entire hydropower complex’s lifespan by several decades.