Phases of a Major Hydropower Project

Aerial view of Eastmain-1-A powerhouse (left) and Eastmain-1 powerhouse (right)

The four phases of a major hydropower project

Technical and economic feasibility, needs of the host community

Consultations and exhaustive environmental and social studies are conducted for Hydro-Québec’s major hydropower projects with a view to developing the best solutions; defining measures to prevent, mitigate or compensate for project impacts; and determining which aspects require environmental follow-up.

A hydroelectric development project has four main phases: planning, draft design (including government permitting), construction and operation.

Stages in a typical project


This stage is for determining the project’s technical and economic feasibility. If the results are conclusive, Hydro-Québec files a project notification with the government authorities to begin the environmental review process.

Draft design and government permitting

The company conducts studies to collect the data required to carry out the project. These studies are used to define the project’s characteristics, set the project schedule and estimate the cost. The environmental studies are also conducted during this phase. An impact statement or environmental assessment is produced according to the applicable article of the Environment Quality Act. These studies cover the environmental impacts assessment, planned mitigation and compensation measures, as well as monitoring and follow-up programs.

Provincial authorities—and sometimes federal authorities—assess the environmental studies. In some cases, the Bureau d’audiences publiques sur l’environnement (BAPE) will hold public hearings and issue recommendations to the Québec government. The federal government may also organize public hearings or the provincial and federal authorities may hold joint hearings.

If the project satisfies all the requirements, the requested permits are issued.

Impact studies: Among the most exhaustive ever conducted in Canada

Hydro-Québec uses recognized scientific methods to ensure the quality of its impact studies and their compliance with government requirements.

All components of the physical, biological and human environments likely to be affected by a project are analyzed.

Hydro-Québec’s impact studies are among the most exhaustive ever conducted in Canada. Examples are the studies for the Eastmain-1-A/Sarcelle/Rupert project and the Romaine complex. Environmental follow-ups are planned for 40 years.

An environmental technician sets up the fish weir for counting Atlantic salmon in the Rivière Romaine, as part of the monitoring of this species.


Compliance monitoring is assured from beginning to end of construction. All the mitigation measures provided for in the impact study are implemented during the construction phase. The compliance officers ensure that contractors and Hydro-Québec employees observe the legislation and adhere to the company’s commitments.


Compliance monitoring continues after the facilities have been commissioned. The actual impacts of the facilities are analyzed compared to expected impacts. The efficacy of the mitigation and compensation measures are assessed, and any necessary adjustments are made. Follow-up programs may last for decades.

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Construction projects