St. Lawrence River

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St. Lawrence River


a river in eastern North America; the outlet for the entire Great Lakes system. The St. Lawrence River proper—from Lake Ontario to the Gulf of St. Lawrence—is approximately 1,200 km long. The entire system—from the upper St. Louis River, which empties into Lake Superior—is 3,350 km long.

The St. Lawrence drains an area of 1,269,000 sq km. Its largest left tributaries are the Ottawa, St. Maurice, and Saguenay rivers; its largest right tributary is the Richelieu, which is linked by canal with the Hudson River in the USA.

The upper St. Lawrence, from Lake Ontario to the city of Cornwall, forms the border between the USA and Canada; the lower St. Lawrence is entirely within Canada. Together with the Great Lakes, the St. Lawrence is the most important natural route between interior North America and the Atlantic Ocean.

The St. Lawrence River valley lies in a broad tectonic basin between the Canadian Shield and the Appalachian Mountains. Between the cities of Prescott and Montreal the river cuts through a narrow spur of the shield; here, a 175-km stretch of rapids, with a gradient of up to 70 m, is bypassed by canals. Below the city of Quebec, the St. Lawrence forms an estuary, approximately 400 km long and up to 50 km wide, at the head of the Gulf of St. Lawrence. In this area, the riverbanks are high and steep.

The St. Lawrence is fed by snow and rain. The mean long-term flow rate at Lake Ontario is 6,750 cu m per sec, and below the mouth of the Ottawa River, approximately 7,800 cu m per sec. The St. Lawrence is icebound from December through April. The estuary does not freeze, but navigation ceases for a period during the spring to allow upstream ice to pass through. Ocean tides reach as far as the city of Trois-Rivières and have a range of 5.5 m at Quebec.

Since 1959, with the completion of the St. Lawrence Seaway, large oceangoing vessels can travel as far as Lake Superior. Between Montreal and Lake Ontario there is a network of power plants, canals, and reservoirs, in addition to the bypass canals. The largest hydroelectric power plant is the St. Lawrence, which furnishes 1.9 gigawatts of electric power to the USA and Canada. The Beauharnois (1.6 gigawatts) and Robert H. Saunders (1.7 gigawatts) plants are Canadian. The chief cities and ports on the St. Lawrence are Kingston, Cornwall, Montreal, Sorel, Trois-Rivières, and Quebec.


References in periodicals archive ?
This practice is also representative of Quebecers' distinctiveness in the sense that it represents testimony to a maritime tradition that belongs uniquely to the Saint Lawrence River.
Mi-careme is also held in two other remote Quebec communities: Natashquan, a native village on the north shore of the Saint Lawrence River, and Cheticamp, an Acadian community.
The text closes where it began, by the Saint Lawrence River, with the answer to the two questions.
Sunday morning, two Massena Border Patrol Station agents, patrolling the Saint Lawrence River in a marked U.
And although the official language is French, spoken by 95 per cent of the population, the Quebecois locals are bi-lingual and the chatter of both French and English are heard along the banks of the Saint Lawrence River.
This 454-mile scenic byway stretches from the shores of Lake Erie in Pennsylvania to the Thousand Islands in the Saint Lawrence River.
Located at a strategic point where the Saint Lawrence River narrows upon its approach to the Great Lakes, the Port of Montreal is an important gateway to the industrial heartland of North America.
Montreal, the largest city of Quebec, is the second largest French-speaking settlement after Paris and is located on the Island of Montreal where Ottawa and Saint Lawrence rivers merge.