Winnipeg River, 813 km long (to head of Firesteel River), issues from the north end of LAKE OF THE WOODS and flows northwest to LAKE WINNIPEG. The river takes its name from the lake, which the Cree called win-nipi, meaning "murky water.
The Winnipeg River has a heavy, rapid flow and was first used for power by a lumber mill at Fort Alexander (now Pine Falls) near the mouth of the river in 1870. Its first hydroelectric power was fed to pulp mills at KENORA, Ont, in 1892, and the first hydroelectric plant on the Manitoba reach began construction at PINAWA in 1903. Today, 7 (6 in Manitoba and one in Ontario) generating stations harness all but a few metres of the river's 106 m drop. The once turbulent river (explorer Alexander MACKENZIE called it the White River because of its many rapids), with its 30 or more portages, is now placid, though still frequented by boats and canoes. From 1965 to 1985 its water was used to cool organic coolant in the Whiteshell Nuclear Research Establishment (now Whiteshell Laboratories).