St. Lawrence River


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Related to St. Lawrence River: St. Lawrence Seaway

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.

A. V. ANTIPOVA

References in periodicals archive ?
The Niagara and St. Lawrence Rivers are unique, but also interconnected.
"Red George" Macdonnell sending the Canadians across a frozen St. Lawrence River to capture Ogdensburg in February 1813.
In its NAFTA submission, Lone Pine argues that Ottawa should shell out $250-million (tax-free) in compensation for "Quebec's arbitrary, capricious, and illegal revocation" of its permit for exploratory drilling under the St. Lawrence River. A panel of three private-sector attorneys will decide the case behind closed doors.
They found the original hypothesis proposed in 1989 by Wally Broecker of Columbia University suggesting that Lake Aggasiz drained into the North Atlantic down the St. Lawrence River would have weakened the thermohaline circulation by less than 15 percent.
"We're seeing a spectacular increase in the growth rate of post-VHS muskellunge in the St. Lawrence River," says Ontario's renowned muskie scientist, Dr.
In New York, Jolliff and Eckert (1971) concluded that the St. Lawrence River sturgeon population below the Moses Saunders Dam at Massena, NY was the only remaining fishery (Jolliff and Eckert, 1971) and probably the only sustainable population with enough individuals not considered in danger of being extirpated.
A new surficial geology map of the St. Lawrence River Estuary illustrates sediment distribution and variability in a relatively confined environment.
Alfred sets off in his homemade submarine up the dark and wilful St. Lawrence River on a quest he's not sure he wants to take.
The six year war ended in 1763 at Montreal on the St. Lawrence River in victory for the British.
Attendees and their guests were treated to a dinner cruise on the good ship Le Coudrier de l'Anse, which endured much rain and some rough waters but could not dampen the spirits of TEI group as they continued the more formal discussions earlier in the day and enjoyed a trip up the St. Lawrence River to the famous Montmorency Falls.
A 66-year-old Anishinabe elder, Josephine Mandamin, engaged on a monthlong treck from Thunder Bay, Ontario to Riviere de La Madeleine, Quebec in order to draw attention of the condition of the Great Lakes and St. Lawrence River.
Lawrence Cement, relocating headquarters from Montreal to Concord, Ontario; and, b) 56 years after (pre-Holcim) Holderbank staked claim to the Quebec market with construction of a cement plant on the St. Lawrence River. Through capital investment and strategic acquisitions, St.