List of longest rivers of Canada
Nine rivers in this list cross international boundaries or form them. Four—the Yukon, Columbia, Porcupine, and Kootenay—begin in Canada and flow into the United States. Five—the Milk, Pend d'Oreille, Saint Lawrence, Red, and Saint John—begin in the United States and flow into Canada. Of these, the Milk and the Kootenay cross the international border twice, the Milk leaving and then re-entering the United States, the Kootenay leaving and then re-entering Canada. The drainage basins of these nine rivers extend into both countries; in addition, the drainage basins of six others—the Fraser, Assiniboine, South Saskatchewan, Saskatchewan, Nelson, and Winnipeg—extend into the United States even though their main stems flow entirely within Canada.
Tar Sands Healing Walk
Canada is home to two of the three largest dams in the world. They are used to hold back toxic sludge from the oil sands. 11 million litres of toxic wastewater seep out of the tailing pits into the boreal forest and Athabasca river every day. That is 4 billion litres a year. Air pollutant guidelines in Alberta are less stringent than international standards. Despite that, air quality objectives were exceeded 1,556 times in 2009, up from 47 times in 2004.