LG2 Dam James Bay Hydroelectric Project on La Grande River, Canada

A rockfill dam with a crest length exceeding 3 kilometers and a height of 160 meters. These are the figures for the gigantic LG2 dam, the main structure of the James Bay hydroelectric complex on the La Grande River in Canada.

Due to its size, the LG2 dam creates one of the largest artificial reservoirs in the world, with an area of 2,830 km² and a capacity of 62 billion cubic meters of water. To contain it, four smaller side dams also had to be constructed. The impermeable inner core, which accounts for 20% of the embankment's total volume, is made of compact glacial moraine, treated with a grizzly and partially dried in large rotary kilns to reduce moisture to the required percentage. Completing the structure is a spillway channel located at the northern end of the main dam, 2,896 meters long and 122 meters wide. This channel has a total discharge capacity of 15,200 m³/sec.

The idea of harnessing the area's enormous water resources dates back to the 1970s when the Quebec government launched the "James Bay Hydroelectric Project," dividing the region's river system into large hydroelectric schemes. The project included a series of large-scale interventions, such as diverting the Eastmain and Opinaca rivers to flow into the La Grande, where a system of dams and power plants was then built.