The Caniapiscau Reservoir () is a reservoir on the upper Caniapiscau River in the Côte-Nord administrative region of the Canadian province of Quebec. It is the largest body of water in Quebec and the second largest reservoir in Canada.
The Caniapiscau Reservoir, formed by two dams and forty-three dikes, is the largest reservoir in surface area of the James Bay Project. As headpond, it feeds the power plants of the La Grande complex in the winter and provides up to 35% of their production. It is isolated from society and there are very few gas stations or other services nearby.
History
thumb|left|Map of the Caniapiscau Reservoir
thumb|left|Caniapiscau Reservoir
The natural lakes of the region were formed about nine thousand years ago as glaciers left Quebec after having scoured the Canadian Shield for ninety thousand years. The prototype of these lakes was an ice dam lake that drained southwards into the Gulf of Saint Lawrence at a time when areas further north (Nunavik) were still glaciated. As post-glacial rebound elevated the southern part of the Canadian Shield more rapidly than the north, the region began to drain northward into the Caniapiscau River, a tributary of the Koksoak River, and ultimately into Ungava Bay.
Prior to impoundment, Lake Caniapiscau covered about and was frequented by hunters and fur traders in the 19th century. In 1834, the Hudson's Bay Company opened an outpost there to link its facilities in the James Bay region with those of Ungava Bay, but closed the Kaniapiskau Post in 1870.
Flora
The Caniapiscau Reservoir is in the zone of discontinuous permafrost. The area surrounding the reservoir is vegetated entirely with taiga, or boreal forest, characterized by widely spaced Black Spruce with a thick underlayer of yellow-grey lichen and interspersed with muskeg and bogs. In the more moist areas, some closed coniferous forest stands may appear. On the more exposed land, a forest-tundra transition zone occurs where the woodland is replaced by lichen dominated tundra.