Ottawa River drainage basin
The Ottawa River drainage basin is the drainage basin in northern North America where surface water empties into the Ottawa River and adjoining waters. Spanning an area of about , it is the 12th largest drainage basin in Canada, occupying the Canadian provinces of Ontario and Quebec. It accounts for about 11% of the total Saint Lawrence River drainage area.
Pollution in Canada
Pollution of the Great Lakes, the world’s biggest bodies of fresh water, continue to be a significant problem for both Canada and the United States. According to Derek Stack, executive director of Great Lakes United, "High pollution levels in the Great Lakes basin continue to take an apparent toll on the air and water quality of the ecosystem." 
In 2002, it was reported that the Great Lakes basin was home to 45% of all toxic air pollution in Canada, in turn affecting the Great Lakes' water. An even more recent report suggests that the Alberta oil sands' impact could reach as far as the Great Lakes. The report warns that "[oil] refineries will be using the Great Lakes ‘as a cheap supply’ source for their copious water needs and the area’s air ‘as a pollution dump'."