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Eastmain 1-A and Rupert River Diversion Hydropower Project

The Selected Project


Project background

The James Bay and Northern Québec Agreement (JBNQA), signed in 1975, provided for the construction of a certain number of hydroelectric projects, notably the Nottaway-Broadback-Rupert (NBR) project. This large-scale undertaking, which included the construction of up to six powerhouses on the Rupert River, seven powerhouses on the Broadback River, as well as the creation of large reservoirs, would have had undeniable social and biophysical impacts on the present-day communities of Mistissini, Waswanipi and Waskaganish. With the signing of the Agreement respecting the establishment of a new relationship between the Government of Québec and the Grand Council of the Crees of Québec in February 2002, this project would be permanently abandoned in favour of the implementation of the Eastmain-1-A and Rupert River diversion project.

The project involves the partial diversion of the Rupert River flow to the La Grande Rivière watershed, thus increasing the volume of water turbined in the two existing powerhouses, while adding two new powerhouses, the Eastmain-1-A and the La Sarcelle, to the proponent’s facilities. The project also includes the construction of control structures which will help in maintaining an ecological instream flow in the reduced flow reach of the Rupert River. Two diversion bays1 will be created by the diversion of waters to the Eastmain-1 reservoir, which will cause the flooding of land areas.

Project options

As part of its project, the proponent submitted, for analysis, a certain number of diversion variants, which were discussed with the Crees and presented in the impact study. In its analysis of the proposed options, the Ministère retained a range of criteria such as flooded land area, the protection of Category II lands as defined in the JBNQA, and the shortening of lengths of rivers with reduced flow capacity. The selected option was the Cramoisy variant, named after a lake located near the passage of the diverted waters. This variant protects the Category II lands of Mistissini, limits the amount of land area submerged by diversion and shortens the length of the river with reduced flow.

Selected project

The project authorized by the Ministère as part of the northern social and environmental impacts review procedure includes the following components:

  • construction and operation of the Eastmain-1-A powerhouse, with a total installed capacity of 768 MW, at the Eastmain-1 Reservoir watershed;

  • construction and operation of the Sarcelle powerhouse, with a total installed capacity of 125 MW, at the Opinaca Reservoir watershed;

  • construction of a 474 m long by 29 m high rockfill dam, with 9 m wide crest, at kilometric point (KP) 314 of Rupert River;

  • diversion of a portion of the waters of Rupert River toward the Eastmain-1 Reservoir, through the forebay (south) and tailbay (north) of the Rupert River, which are linked by a 2.9 km long tunnel under De la Sillimanite Lake. Diverted waters from Rupert River will then follow the course of the Eastmain-1 Reservoir waters up to the mouth of La Grande Rivière River, via Eastmain River, the Opinaca Reservoir, Boyd Lake, Sakami Lake, Sakami River and the Robert-Bourassa Reservoir;

  • diverted waters will be turbined in the new powerhouses (Eastmain-1-A and De la Sarcelle) as well as in the existing powerhouses (Robert-Bourassa and La Grande-1), which will help to maximize hydropower generation in both new and existing powerhouses;

  • construction of a flow-control structure (spillway) at KP 314 of Rupert River, to release ecological instream flows in Rupert River. These flows, modulated according to the seasons, will ensure the protection of fish species life cycles;

  • construction of control structures on Lemare River, Nemiscau River, Arques Creek and Kayechischekaw Creek, to restore the natural flows of these watercourses, which are impacted by a reach and to ensure biological integrity;

  • construction of eight hydraulic structures on Rupert River to maintain the river's uses downstream of the control structure and preserve 91% of aquatic environment, as well as spawning grounds, feeding habitats and aquatic grass beds;

  • construction of 2 315 kV transmission lines enabling connection of the, Eastmain-1-A and Sarcelle powerhouses to the Québec grid;

  • eight work camps to house workers, including three existing work camps and five temporary ones;

  • construction of roughly 255 km of roads, and upgrading of approximately 105 km of existing roads;

  • construction of a new drinking water plant for the Waskaganish community.

Project justification

With regards to the project's justification, the Ministère has drawn the following conclusions:

  • The proponent may profit from the existing infrastructures to produce more energy at an advantageous cost;

  • The project is feasible on from an economic standpoint in view of the production cost, execution costs and reasonable expectations of profit on the internal and external markets;

  • The project may significantly contribute to achieving the desired manoeuvring margin of 15 TWh, which will help the proponent respond to the internal demand variations and at the same time take advantage of export markets;

  • In view of lowering of provisions of additional supply required by 2014, the improvement of the proponent’s manoeuvring margin and export are the essential reason behind the project. COMEX recognizes the legitimacy of these reasons as part of the corporate strategy and conform to Québec’s energy strategy;

  • The project will contribute to the increase of dividends that the proponent will pay to the Government of Québec, to the profit of the whole Québec society;

  • As of today, there is no alternative solution and no combination of alternative solutions that could guarantee the same operational and economic advantages as this project;

  • Wind energy production represents an interesting addition to this project and will benefit from its implementation, but it cannot replace it.


 1 The difference between a diversion bay and a reservoir consists in a reduced drawdown, a poor water storage capacity and, generally, better quality habitats, from a biological point of view.

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