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.
Mackenzie River
Through its many tributaries, the Mackenzie River basin covers portions of five Canadian provinces and territories – British Columbia (BC), Alberta, Saskatchewan, Yukon, and Northwest Territories. Thutade Lake, in the Northern Interior of BC, is the ultimate source of the Mackenzie River via the Finlay–Peace River system, which stretches through BC and Alberta. The Athabasca River originates further south, in Jasper National Park in southwest Alberta. Together, the Peace and Athabasca rivers drain a significant portion of the eastern slope of the Rocky Mountains and the central Alberta prairie. The Peace contributes the majority of the water, about 66 km (54 million acre-feet) per year, and the Athabasca contributes 25 km (20 million acre-feet).