In 2006, once the dam has been built, water from the Eastmain River will form a reservoir 35 km long with a total area of 603 km2. After being turbined in the powerhouse, water from the reservoir will return to the river to flow into Opinaca reservoir and then into Robert-Bourassa reservoir. The same water will therefore be turbined at three generating stations: Eastmain-1, Robert-Bourassa or La Grande-2-A, and La Grande-1, before flowing into James Bay.