The Kootenai River is one of the largest rivers in the Northwest, originating in the Canadian Rockies of British Columbia before flowing south and west through Montana, then northwest through Idaho, finally returning to Canada where it flows through Kootenay Lake to join the Columbia River. At the Idaho border near Leonia (the lowest elevation point in Montana at 1,820 feet), the river drains approximately 13,000 square miles with an average discharge of 16,100 cfs. The construction of Libby Dam in 1972 created Lake Koocanusa and dramatically altered the river system, changing its natural flow patterns, temperature, and productivity regimes. Below the dam, the Kootenai flows for approximately 50 miles to the Idaho border through a landscape of forested mountains. The river is characterized by its immense size, powerful current, and crystal-clear water that provides exceptional visibility most of the year.