Columbia River
The Columbia drains an area of about . Its drainage basin covers nearly all of Idaho, large portions of British Columbia, Oregon, and Washington, ultimately all of Montana west of the Continental Divide, and small portions of Wyoming, Utah, and Nevada; the total area is similar to the size of France. Roughly of the river's length and 85 percent of its drainage basin are in the US. The Columbia is the twelfth-longest river and has the sixth-largest drainage basin in the United States. In Canada, where the Columbia flows for and drains , the river ranks 23rd in length, and the Canadian part of its basin ranks 13th in size among Canadian basins. 
The Columbia shares its name with nearby places, such as British Columbia, as well as with landforms and bodies of water.
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.