What is the Pacific drainage basin in Canada?

The Pacific drainage basin in Canada covers about 1.04 million square kilometres, about 10.5 per cent of Canada's land area, including most of British Columbia and most of Yukon. All rivers in the basin ultimately drain to the Pacific Ocean via the Fraser, Skeena, Stikine, Nass, Yukon, Columbia, and other rivers. The basin is bounded by the Continental Divide of the Rocky Mountains in the east, where the boundary between Pacific and Arctic/Hudson Bay drainage runs.

The Fraser River (1,375 kilometres, BC's longest river) is the largest entirely Canadian river in the Pacific basin, draining 220,000 square kilometres of central and southern British Columbia. The Yukon River (3,190 kilometres total, with about 1,150 kilometres in Canada) drains most of Yukon and central Alaska. The Columbia River is shared with the United States, with about 800 kilometres in southeastern British Columbia. The Skeena (620 kilometres) and Nass (380 kilometres) Rivers drain north-central British Columbia. The Stikine, Taku, and Alsek Rivers drain northwestern British Columbia and southwestern Yukon to the Alaska coast.

The Pacific drainage basin supports about 60 per cent of British Columbia's hydroelectric generation. BC Hydro's Mica, Revelstoke, Hugh L. Keenleyside, Peace Canyon, and Site C dams (the latter completed in 2025) on the Columbia and Peace Rivers (the Peace flows north into the Mackenzie system but its headwaters are in the Pacific basin) produce a substantial fraction of BC's electricity. The Pacific basin also supports significant Indigenous-led run-of-river hydroelectric projects.

The Pacific basin supports the most diverse fisheries in Canada. Five species of Pacific salmon (sockeye, chinook, coho, chum, and pink) spawn in tributary streams, with the Fraser River supporting the world's largest individual sockeye run (the 2010 return of 28 million fish was the largest in 100 years). Steelhead, rainbow/coastal cutthroat trout, and bull trout are important freshwater species. The federal Pacific Salmon Treaty (1985, with major amendments) governs Canada-US shared salmon management, and the federal Wild Salmon Policy and Pacific Salmon Strategy Initiative (2021, $647 million over 5 years) address declining stocks. The First Nations of the Pacific basin include the Sto:lo, Tsilhqot'in, Secwepemc, Nlaka'pamux, Stl'atl'imx, Syilx, Ktunaxa, Carrier, Wet'suwet'en, Tahltan, Haisla, Tsimshian, Nisga'a, Heiltsuk, Wuikinuxv, Nuxalk, Coast Salish, Nuu-chah-nulth, Kwakwaka'wakw, and several Yukon First Nations.