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.

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 Lake Ontario to the Atlantic Ocean.

History

Proposals for the Seaway started in 1909, but was met with resistance from railway and port lobbyists in the US. In addition to replacing the canal system, generation of hydroelectricity also drove the project. After rejecting numerous agreements to construct a Seaway, construction was approved in 1954 when Canada declared it was ready to proceed unilaterally. The Seaway opened in 1959 and cost $470 million US dollars, $336.2 million of which was paid by the Canadian government. Queen Elizabeth II and President Dwight Eisenhower formally opened the Seaway with a short cruise aboard Royal Yacht Britannia after addressing the crowds in St. Lambert, Quebec.

The seaway's opening is often credited with making the Erie Canal obsolete, thus setting off the severe economic decline of several cities in upstate New York.

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) (panamax depth) 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). In the late 1990s the seaway has been deepened and widened increasing near panamax sized ship access upstream from the Atlantic ocean to Montreal.

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.

Environmental effects

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 Basin. These organisms were introduced via ballast water from oceanic vessels.

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.

Notes

References

• Seaway Handbook issued by the St. Lawrence Seaway Management Corporation, (Head Office, 202 Pitt Street, Cornwall, Ontario, Canada K6J 3P7) 2006.
• Willoughby, William R. (1961). The St. Lawrence Waterway: A Study in Politics and Diplomacy. Madison, University of Wisconsin Press. (Worldcat link: )

External links

• Great Lakes St Lawrence Seaway System web site
• The St Lawrence Seaway Development Corporation
• The Lost Villages Historical Society
• Excerpt from the Illustrated London News, January 11, 1862 describing the Canals of Canada.
• Exchange of Notes, amending 1959 Agreement of Application of Tolls
• CBC Digital Archives — The St Lawrence Seaway: Gateway to the world
• Bibliography on Water Resources and International Law See Great Lakes; St. Lawrence River and Seaway. Peace Palace Libray
• Channel Depth and Width information