Project summary

This project involves the partial diversion (71%) of the waters of the Rupert River starting at kilometre 314. The diverted waters are routed north through the La Grande River to increase the power produced at the Robert-Bourassa, La Grande-2-A and La Grande-1 powerhouses. Annual production is assessed at 8.5 TWh.

On the reduced-flow section of the Rupert River, the proponent has constructed eight hydraulic structures to prevent exposure of the riverbanks, among other things. The project also included the creation of the upstream and downstream Rupert diversion bays, including the construction of dams on the Lemare and Nemiscau rivers and several dikes, as well as the construction of a transfer tunnel for the movement of water between the two diversion bays. The construction of the Eastmain-1-A powerhouse, with an installed capacity of 768 MW, and the Sarcelle powerhouse, installed capacity of 150 MW, were integral parts of the project.

The project also included the construction of the permanent Muskeg-Eastmain road, 40 km in length, and a 101 km, 315 kV transmission line. Several temporary camps to house 5,500 workers were also planned. The cost of the project, including the cost of financing, was estimated at $4 billion.

Since 2006, the project has been subject to numeros conditions arising from the initial certificate of authorization and subsequent amendments, generating numerous follow-ups also reviewed by COMEX.

Details on location

The Eastmain-1-A and Rupert diversion project extends over a large part of the Eeyou Istchee James Bay Territory (formerly known as the Municipality of James Bay). To the south, a dam at km 314 on the Rupert River diverts part of the river’s flow northward. There are 8 hydraulic structures on the Rupert River between km 0 and 314. To the north of the Rupert, dams were built on the Lemare and Nemiscau rivers, and the Rupert diversion bays were created. This allows the waters from the partial diversion of the Rupert River to flow to the Eastmain-1, Eastmain-1-A and Sarcelle powerhouses and to the La Grande Complex further north.