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Saint Lawrence Seaway

2007 Schools Wikipedia Selection. Related subjects: Air & Sea transport;
North American Geography

   The Eisenhower Locks in Massena, NY.
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   The Eisenhower Locks in Massena, NY.

   The St Lawrence Seaway is the common name for a system of canals that
   permits ocean-going vessels to travel from the Atlantic Ocean to the
   Great Lakes as far as Lake Superior. Legally it extends from Montreal
   to Lake Erie, including the Welland Canal and the Great Lakes Waterway.
   The seaway is named after the Saint Lawrence River, which it follows
   from the Atlantic Ocean to Lake Ontario.

Route

   Beginning in the Saint Lawrence River, the seaway leaves Quebec through
   Lac Saint-François, passing through the Akwesasne Mohawk First Nation.
   At 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. Cornwall and Massena are joined by an international
   bridge over the St. Lawrence, the Seaway International Bridge, named
   for the seaway.

   Between Cornwall and 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 (five Canadian, two American).

   The Welland Canal (eight locks) links Lake Ontario (surface elevation
   74m) to Lake Erie (surface elevation 173m), 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 (surface elevation 183m) with Lake Huron
   (surface elevation 176m). This short canal is operated toll-free by the
   U.S. Army Corps of Engineers, not by the joint U.S.-Canada Saint
   Lawrence Seaway Management Corporation. They are often not considered
   part of the St. Lawrence Seaway, although they are an integral part of
   the system.

   The seaway was first used on April 25, 1959, although it was not
   officially opened until June 26, 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, an artificial lake had to be
   created. Called Lake St. 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. At the time of its construction, 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.

   The seaway provides significant entertainment and recreation such as
   boating, camping, fishing, and scuba diving. Of particular note is that
   the seaway provides a number of divable wrecks within recreational
   scuba limits (shallower than 130 ft.). Surprisingly, the water
   temperature can be as warm as 70°F with little or no thermocline during
   the mid to late summer months.

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, known
   informally as Seaway-Max. Large vessels of the lake freighter fleet are
   built on the Lakes and cannot 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, but 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 seaway is 41 feet (12.5 m) downstream of Quebec City, 35 feet (10.7
   m) between Quebec City and Deschaillons, 37 feet (11.3 m) to Montreal,
   and 28 feet (8.2 m ) upstream of Montreal. Channels in the Great Lakes
   Waterway are slightly shallower: 25 to 27 feet (7.62 to 8.2 m).

   Channel depths and limited lock sizes mean that only 10% of ocean-going
   ships can traverse the entire seaway. Proposals to expand the seaway,
   dating from as early as the 1960s, have been rejected as too costly,
   and environmentally and economically unsound. Lower water levels in the
   Great Lakes have also posed problems for some vessels in recent years.

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. These were
   generally too small to allow passage of larger ocean-going ships.
   Retrieved from " http://en.wikipedia.org/wiki/Saint_Lawrence_Seaway"
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