St. Lawrence Seaway
The first sod on the St. Lawrence Power Project was turned on August 10, 1954. Work on the Seaway began in September of the same year. The construction schedule for the entire power and Seaway project was in great part determined by both the Hydro-Electric Power Commission of Ontario and the Power Authority of the State of New York who were planning to start joint operation in 1958.
In order to allow a 36.6 m (120 feet) clearance to the vessels, the structure of four of the Montreal area bridges had to be modified drastically without interrupting the heavy vehicular and rail traffic to and from the city. The digging of new channels and extensive dredging to existing ones brought unforeseen difficulties – excavators uncovered rock formations that played havoc with standard equipment and necessitated the creation of new methods and the use of stronger machinery. The power development, which called for the flooding of wide areas, required the expropriation of some 260 km2(100 square miles) of land and the resettlement of entire communities.
In all, some 6,500 people were moved to new homes while some 550 dwellings were transported to awaiting foundations in the newly created towns of Long Sault, Ingleside and Iroquois. In the Welland Canal, rock dredging during the winter months brought the 7.6 m (25 feet)deep channel to the 8.2 m (27 feet) governing depth of the Seaway. All of the seven locks of the Montreal/Lake Ontario section of the Seaway (St. Lambert, Coote Ste. Catherine, Lower and Upper Beauharnois, Bertrand H. Snell, Dwight D. Eisenhower and Iroquois) as well as those of the Welland Canal, have been built to the following standard dimensions:
Seaway channels and canals were built to minimum widths of 61 m (200 feet) when provided with two embankments, 91.4 m (300 feet) when there is only one embankment, and 137.2 m (450 feet) in open reaches. Depth throughout is 8.2 m (27 feet).
By May 1958, the Iroquois Lock was in regular use. The Snell and Eisenhower Locks, built by the Americans at Massena, New York, became operative on July 4 and on that same day, first power came from the international Moses Saunders generating station.