Canadian River Systems
Canada is rich in rivers and lakes with nearly 300,000 square miles (780,000 sq km) of freshwater, representing 7.6% of the total area of the country. The waterways were the routes by which the canoes of the explorers penetrated the interior, and they played a vital role in the fur trade and the opening of the country to settlers.
There are four great drainage basins. Their rivers flow into Hudson Bay and into the Arctic, Atlantic, and Pacific oceans. In addition, a small area of some 12,365 square miles (32,025 sq km) in the extreme south of Alberta and Saskatchewan drains by the Mississippi River system into the Gulf of Mexico.
Hudson Bay Drainage Basin
Many large rivers flow into the Hudson Bay drainage basin, which includes the area draining into Hudson Strait, Foxe Basin, James Bay, and Ungava Bay, making this the largest of the basins (1,421,350 square miles, or 3,681,300 sq km). The Nelson, its largest river, drains Lake Winnipeg, which itself receives the waters of the North Saskatchewan, South Saskatchewan, Red, Assiniboine, and Winnipeg rivers. This river system provided access to the interior for British explorers, became the main artery for the fur traders of the Hudson's Bay Company, and was followed by the Red River settlers early in the 19th century.
Arctic Drainage Basin
The Arctic drainage basin (1,380,895 square miles, or 3,576,520 sq km) is dominated by the Mackenzie River system, which includes Lake Athabasca, Great Slave Lake, and Great Bear Lake. From the head of the Finlay to the mouth of the Mackenzie is 2,635 miles (4,240 km), making this the longest river in Canada; the lower 1,700 miles (2,740 km) is navigable for tug boats and barges, except for a 16-mile (25 km) portage around the series of rapids at the Alberta–Northwest Territories border.
Atlantic Drainage Basin
In the Atlantic drainage basin (580,097 square miles, or 1,502,450 sq km), the St. Lawrence River, with the Ottawa River as its most important tributary, is preeminent. The flow of the St. Lawrence, which drains the Great Lakes, is exceeded in North America only by that of the Mississippi River. Apart from Lake Michigan, which is wholly in the United States, the Great Lakes lie partly in Canada and partly in the United States. They cover an area of nearly 95,000 square miles (246,050 sq km) and contain 5,500 cubic miles (22,800 cu km) of water, which is about one-fourth of the fresh surface-water supply of the world.
The St. Lawrence system was followed by the French explorers and the Montreal fur traders and was to become the main commercial highway of Canada serving its industrial heartland. Since the opening of the St. Lawrence Seaway in 1959, oceangoing vessels can sail to the head of the Great Lakes, which is a distance of 2,388 miles (3,842 km) from the Atlantic Ocean at the Strait of Belle Isle.
Pacific Drainage Basin
The Pacific drainage basin (400,730 square miles, or 1,037,890 sq km), the smallest of the basins, includes the areas with the highest precipitation in Canada. The basin has three major rivers, the Fraser, the Columbia, and the Yukon. The Fraser, which lies wholly within Canada, and the Columbia, which flows for over one-half its length in the United States, rise in the Cordillera and empty into the Pacific Ocean. Numerous falls and rapids make them unsuitable for navigation. The Yukon, flowing from Canada through Alaska to the Bering Sea, is the fifth largest river in North America. It is navigable for 1,777 miles (2,858 km), from Whitehorse to its mouth, and was used by river steamers at the time of the Klondike gold rush for supplying Dawson City.