Saint Lawrence Seaway (redirected from St Lawrence Seaway)

Saint Lawrence Seaway, international waterway, 2,342 mi (3,769 km) long, consisting of a system of canals, dams, and locks in the St. Lawrence River and connecting channels between the Great Lakes; opened 1959. It provides passage for large oceangoing vessels into central North America. The seaway includes a 27-ft (8-m) deep waterway, a canal, and seven locks between the port of Montreal and Lake Ontario; a 27-ft (8-m) channel and eight locks through the Welland Ship Canal; and the Sault Sainte Marie Canals and locks.

The seaway has created a fourth seacoast accessible to the industrial and agricultural heartland of North America and has brought oceangoing vessels to lake ports such as Buffalo, Cleveland, Toledo, Detroit, Chicago, Milwaukee, Duluth, and Toronto. The maximum vessel size is 730 ft (223 m) in length with a cargo capacity of 28,000 tons. The shipping season has been extended to 250 days (mid-April to mid-December) by increased use of icebreakers and air pumps to control ice formation in the locks. Iron ore, wheat, and coal are the principal cargoes carried on the seaway.

Construction of the project was authorized by Canada in 1951 and by the United States in 1954. The St. Lawrence Seaway Authority was charged with construction and maintenance of required facilities in Canada; the St. Lawrence Seaway Development Corporation was responsible for facilities in the United States. Principal new locks on the St. Lawrence River section of the seaway are, from east to west, St. Lambert (18 ft/5.5 m lift); Côte Ste Catherine (30 ft/9.1 m), which enables vessels to bypass the Lachine Rapids; Lower and Upper Beauharnois (82 ft/25 m, including the Beauharnois Canal built in 1932); Bertrand H. Snell (45 ft/13.7 m); Dwight D. Eisenhower (38 ft/11.6 m); and Iroquois Guard Lock (3 ft/91 cm). Hydroelectric facilities were integrated with the project and developed and operated by the Power Authority of the State of New York and the Hydro-Electric Power Commission of Ontario.

Bibliography

See L. Thomas, Story of the St. Lawrence Seaway (1972); G. Sussman, The St. Lawrence Seaway (1978).

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Saint Lawrence Seaway

U.S.-Canadian waterway and lock system. Located along the upper St. Lawrence River, it links the Atlantic Ocean with the Great Lakes. Its construction, carried out in 1954–59, involved clearing a 186-mi (299-km) stretch of the St. Lawrence River between Montreal and Lake Ontario. It included lakes, rivers, locks, and canals that extended for 2,340 mi (3,766 km) to connect Duluth, Minn., with the head of the Gulf of St. Lawrence. With the Great Lakes, it provides 9,500 mi (15,285 km) of navigable waterways. It allows deep-draft ocean vessels access to the Great Lakes' rich industrial and agricultural regions. It is navigable from April to mid-December.

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Saint Lawrence Seaway

an inland waterway of North America, passing through the Great Lakes, the St Lawrence River, and connecting canals and locks: one of the most important waterways in the world. Length: 3993 km (2480 miles)