Caniapiscau River

The Caniapiscau River (in French, "rivière Caniapiscau") is a tributary of the Koksoak River in Nunavik, Québec, Canada. Since 1985, the headwaters of the Caniapiscau River have been diverted into the La Grande hydroelectric complex.

Rising at an altitude of over 500 metres in the Canadian Shield, the Caniapiscau River flows northward through a wide, timbered glacial valley until it makes a sharp turn at its confluence with the Rivière aux Mélèzes (Larch River). At this point, the river becomes the Koksoak River. The total length of the Caniapiscau River is 737 kilometres (458 miles).

The headwaters of the Caniapiscau River, representing about 45% of the total flow, now drain into the La Grande River of James Bay. The Caniapiscau Reservoir, which covers about 4,300 km², or about nine times the size of the natural Lake Caniapiscau, fills a depression in the highest part of the Canadian Shield. The total catchment basin is about 36,800 km².

Important variations in the water flow of the Caniapiscau River from 1981 to 1984, during the period when the Caniapiscau Reservoir was being filled, may have contributed to the death by drowning of 10,000 migratory woodland caribou in September 1984 (about 1,5% of the herd).

The Caniapiscau River basin has no permanent inhabitants, although Cree from the James Bay region as well as southern hunters do travel to the area by road and bush plane.