Saint Lawrence Seaway

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Image:Eisenhower Locks.jpg The Saint Lawrence Seaway in its broadest sense is the system of canals that permits ocean-going vessels to travel from the Atlantic Ocean to the Great Lakes as far as Lake Superior. However, according to law, the Saint Lawrence Seaway extends from Montreal to Lake Erie and includes the Welland Canal while the upper section is the Great Lakes Waterway.

1 Route
2 Lock and channel dimensions
- 2.1 Earlier canals
3 External links

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Route

The seaway begins at the port of Montreal, where the South Shore Canal (St-Lambert and Côte Ste-Catherine canal locks) passes the Lachine Rapids. West of the Island of Montreal and Lac Saint-Louis, the Beauharnois Canal bypasses the Beauharnois hydroelectric dam.

Rejoining the St. Lawrence River proper, the seaway then leaves Quebec through Lac Saint-François, passing north of the Akwesasne Mohawk First Nation. At the towns of Cornwall and Massena, the river and seaway form an international waterway with Ontario on the northern shore and New York State on the southern shore.

West of Cornwall/Massena, the seaway diverges south of the river, passing through New York's Wiley-Dondero Canal, containing the Snell and Eisenhower locks. This route bypasses the Moses-Saunders hydroelectric dam before passing through the short Iroquois Lock on the Canadian side of the river, permitting vessels to bypass the Iroquois water level control structure. West of the Iroquois Lock, the seaway follows the St. Lawrence River through the Thousand Islands and into Lake Ontario. Altogether there are seven locks in the Montreal-Lake Ontario section (5 Canadian, 2 American).

The Welland Canal (eight locks) links Lake Ontario to Lake Erie, bypassing the formidable barrier of Niagara Falls.

West of Lake Ontario in the Great Lakes Waterway the Soo Locks in Sault Ste. Marie, Michigan bypass the rapids on the St. Marys River connecting Lake Superior with Lake Huron. This short canal is operated toll-free by the U.S. Army Corp of Engineers[1] and not by the U.S.-Canada jointly controlled St. Lawrence Seaway Management Corporation, thus they are often not considered part of the St Lawrence Seaway although in practice they are an integral part of the system.

The seaway is co-administered by Canada and the United States. It was first used on April 25, 1959, although it was not officially opened until June 26th, 1959 by Queen Elizabeth II and President Dwight D. Eisenhower.

To create a navigable channel through the Long Sault rapids and to allow hydroelectric stations to be established immediately upriver from Cornwall, Ontario and Massena, New York, a man-made lake had to be created. Called Lake Saint Lawrence, it required the flooding on July 1, 1958 of ten villages in Ontario, now collectively known as "The Lost Villages." There was also inundation on the New York side, but no communities were affected. Although it may seem unremarkable today, at the time the Seaway Project was considered by some to be the largest work of engineering of all time.

The creation of the seaway also led to the introduction of foreign species of aquatic animals, including the sea lamprey and the zebra mussel, into the Great Lakes watershed.

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Lock and channel dimensions

The size of vessels that can traverse the seaway is limited by the size of locks. Locks on the St Lawrence, and on the Welland Canal are 766 feet (233.5 m) long, 80 feet (24 m) wide, and 30 feet (9.1 m) deep. The maximum allowed vessel size is slightly smaller: 740 feet (225.6 m) long, 78 feet (23.8 m) wide, and 26 feet (7.9 m) deep; many vessels designed for use on the Great Lakes following the opening of the seaway were built to the maximum size permissible by the locks, also known informally as Seaway-Max. Larger vessels of the lake freighter fleet are built on the Lakes and can never travel down the Seaway to the ocean. The only lock on the Great Lakes Waterway is 1,200 feet (357 m) long, 110 feet (33.5 m) wide and 32 feet (9.8 m) deep although the channels are not kept that deep.

Water depth is another obstacle to vessels, particularly in connecting waterways such as the St. Lawrence River. The depth in the channels of the St. Lawrence Seaway is 41 feet (12.5 m) downstream of Québec City, 35 feet (10.7 m) between Québec City and Deschaillons, 37 feet (11.3 m) to Montréal, and 27 feet (8.2 m ) upstream of Montréal. Channels in the Great Lakes Waterway section are slightly shallower: 25 to 27 feet (7.62 to 8.2 m).

Channel depths when combined with the limited lock sizes mean that only 10% of the ships currently travelling on the world's oceans can traverse the entire Seaway. Proposals to expand the seaway, dating from as early as the 1960s, have been rejected as too costly, environmentally and economically unsound. Lower water levels in the Great Lakes have also posed problems for some vessels in recent years.

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Earlier canals

In 1862, locks on the St. Lawrence allowed transit of vessels 186 feet (57 m) long, 44½ feet (13.6 m) wide, and 9 feet (2.7 m) deep. The Welland Canal at this time allowed transit of vessels 142 feet (43 m) long, 26 feet (7.9 m) wide, and 10 feet (3.0 m) deep. However, these were generally too small to allow passage to the larger oceangoing ships.

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