Do You Know the Drainage Basins of Canada?

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Do You Know the Drainage Basins of Canada?

A drainage basin is an area that drains all precipitation into a river system and into a common natural reservoir such as a lake or ocean. The major ocean drainage basins of Canada are the Atlantic Ocean, Hudson Bay, the Arctic Ocean, the Pacific Ocean and the Gulf of Mexico. Nearly 75% of the Canadian continental landmass drains waters toward the north either into the Arctic Ocean, or into Hudson Bay and James Bay. For more details: The Atlas of Canada: Drainage Basins.

Did You Know That Canada Has about Two Million Lakes?

The ocean drainage basins of Quebec are Hudson Bay and the Atlantic Ocean, which are divided into four sub-basins: the St. Lawrence River, James Bay and Hudson Bay, Ungava Bay and the Gulf coast (Gulf of St. Lawrence). Although the Great Lakes sub-basin is located outside Quebec (Ontario and the U.S.), its influence is considerable due to its location upstream from the St. Lawrence.

Did You Know That Quebec Contains 20% of Canada’s Freshwater Land Area?

Quebec has the largest freshwater land area (nearly 177 000 km²) of all the provinces, followed by the Northwest Territories and Ontario.

Freshwater and Land Area of Canada
	Total area (km²)	Land (km²)	Fresh water (km²)	Percentage of freshwater area
CANADA	9 984 670	9 093 507	891 163	100
Quebec	1 542 056	1 365 128	176 928	19.8
Northwest Territories	1 346 106	1 183 085	163 021	18.3
Ontario	1 076 395	917 741	158 654	17.8
Nunavut	2 093 190	1 936 113	157 077	17.6
Manitoba	647 797	553 556	94 241	10.6
Saskatchewan	651 036	591 670	59 366	6.7
Newfoundland and Labrador	405 212	373 872	31 340	3.5
British Columbia	944 735	925 186	19 549	2.2
Alberta	661 848	642 317	19 531	2.2
Yukon Territory	482 443	474 391	8 052	0.9
Nova Scotia	55 284	53 338	1 946	0.2
New Brunswick	72 908	71 450	1 458	0.2
Prince Edward Island	5 660	5 660	0	0
Source: Table based on Statistics Canada’s Related Tables: Natural Resources. Online. <http://www40.statcan.ca/l01/cst01/phys01.htm>. Consulted on October 3, 2006.

The St. Lawrence River Compared to the World’s Major Rivers

The St. Lawrence–Great Lakes is one of the largest hydrographic systems in the world. It drains more than 25% of the earth’s reserves of fresh water and influences the environmental processes of the entire North American continent.

Its drainage basin is the second-largest in Canada, after that of the Mackenzie River, and the third-largest in North America, after that of the Mississippi and Mackenzie rivers.

Here’s how the hydrographic system of the St. Lawrence–Great Lakes stacks up worldwide:

It has the world’s 13th largest drainage basin, at 610 000 km²;
It ranks 16th for its mean annual flow, 12 600 m³/s just off Quebec City;
It is the 17th longest, at 3260 km starting from Lake Superior to the Cabot Strait.

Map: The St. Lawrence River Compared to the World?s Major Rivers

Continent	River	Length (km)	Drainage basin (km2)	Mean annual flow (m3/s)
AFRICA	Nile	6 670	2 849 000	2 830
AFRICA	Zaïre (or Congo)	4 630	3 774 000	39 200
NORTH AMERICA	Mackenzie (and Peace)	4 240	1 787 000	9 600
	Mississippi (and Missouri)	5 970	3 290 000	18 400
	St. Lawrence (and Great Lakes)	3 260	1 610 000	12 600
SOUTH AMERICA	Amazon	6 570	6 300 000	175 000
SOUTH AMERICA	Paraná (and Rio de la Plata)	4 880	3 100 000	25 000
ASIA	Ganges (and Brahmaputra)	2 510	1 733 000	31 000
	Lena	4 400	2 430 000	16 300
	Ob (and Irtysch)	5 410	2 500 000	12 350
	Yangtze	6 300	1 808 000	34 000
AUSTRALIA	Murray (and Darling)	3 750	1059 000	350
EUROPE	Danube	2 860	817 000	6 550
	Rhine	1 320	185 000	2 500
	Rhone	810	96 000	2 200
	Volga	3 530	1 350 000	8 400

The St. Lawrence River

Source	Great Lakes
Mouth	Atlantic Ocean
Tributaries	Roughly 350 tributary rivers feed into the Quebec portion of the river.
Climate	Cold temperate with no dry season
Population	97% of Quebecers (approximately 7 million people) live within the boundaries of the drainage basin.

Literature

Cossa, D., T. T. Pham, B. Rondeau, S. Proulx, C. Surette, and B. Quémerais. 1998. Tracking Contaminants in the St. Lawrence River: Summary of the Mass Balance Study of Contaminants in the St. Lawrence River. Environment Canada – Quebec Region, Environmental Conservation, St. Lawrence Centre.

Gingras, D. 1997. The River at a Glance. "St. Lawrence UPDATE" series. Info-flash sheets on the state of the St. Lawrence River. Environment Canada – Quebec Region, Environmental Conservation, St. Lawrence Centre.

St. Lawrence Centre. 1996. State of the Environment Report on the State of the St. Lawrence River. Volume 1. The St. Lawrence Ecosystem. "St. Lawrence UPDATE" series. Environment Canada – Quebec Region, Environmental Conservation, and Les Éditions MultiMondes, Montreal.