Atlantic Ocean watershed

The Atlantic Ocean watershed spreads over all eastern Canada and covers an area of 1.6 million km2.  It is dominated by the Great Lakes, namely Lakes Superior, Erie, Huron, Michigan and Ontario, and the St. Lawrence River, and includes the lakes and the rivers from the Atlantic coast such as the Churchill River (in Labrador) and the Saint John River (in New Brunswick).


Map of outline of Canada's Atlantic Ocean watershed.

Great Lakes

The Great Lakes are a vast shared resource containing a significant portion of the world's freshwater. They are fundamental to the well-being of many Canadians and Americans, as well as sustaining a rich variety of plants and animals. The Great Lakes provide the foundation for billions of dollars in economic activity, and they are a direct source of drinking water for millions of Canadians.

Lake Simcoe

St. Lawrence River

The St. Lawrence River harbours a complex ecosystem whose physical properties vary from upstream to downstream. It includes lakes and freshwater reaches, a long estuary, and a gulf with marine features. The area is home to richly diverse habitats and an equally rich diversity of flora and fauna.

St. Croix River

The St. Croix River watershed covers an area of 1,649 square miles (4,271 km2) along the Canada and United States border between New Brunswick and Maine. The 110-mile (185 km) St. Croix River serves as a natural boundary between Canada and the United States. Because of its strategic location, the river has played a unique role in the history of Maritime Canada and the U.S. and remains important for these reasons today (CHRS 2007).

Saint John River

The Saint John River, which has a rich history of colonization, commercial development, forestry, agriculture, and fishing, is the largest river basin in the Maritimes at 55,100 km2. It’s headwaters originate in both the province of Quebec and the state of Maine and flows 673 km southeast through New Brunswick before reaching the Bay of Fundy.

Churchill River

The Churchill River, the largest river within the Atlantic provinces, drains an area nearly 80,000 km2 with an average discharge of 1,740 m3/sec. The Churchill is an important socio-economic resource as the site for Canada’s second largest hydroelectric facility, Churchill Falls, and assessments are currently underway for adding new hydroelectric facilities further downstream.

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