The St. Lawrence Seaway

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Arguably the most important waterway in Canadian history, the St. Lawrence River was the highway for trade for centuries during European settlement, and long before that for the Indigenous.

While the St. Lawrence River was important, there was the hope that ships could eventually go from the river into the Great Lakes all the way to Lake Superior. Such a system would revolutionize trade in North America.

This is where the St. Lawrence Seaway comes in.

The first bit of St. Lawrence Seaway work, technically, begins in 1680 when the Superior of a Seminary in Montreal began to dig a 1.5 metre deep canal to bypass the Lachine Rapids. The Lachine Canal, something I talked about awhile ago on the podcast, would finally be completed in 1824.

The road to the St. Lawrence Seaway would begin in 1871 when locks were built on the St. Lawrence allowing for vessels 57 metres in length, 2.7 metres deep and 14 metres wide to travel on the river.

A few weeks ago, I covered the Welland Canal, which was built through four different incarnations from the early 1800s to 1930s. This allowed for a connection between Lake Erie and Lake Ontario but the United States was reluctant to go into a larger venture that would connect much more of the waterways.

In the 1890s, the first talks of creating a seaway between Canada and the United States would occur but they would progress very little in moving towards creating the seaway.

In 1909, the first joint U.S.-Canadian Deep Waterways Commission is formed to study the possibility of the Seaway, and while it recommends it, the Seaway itself is a long way off.

By the 1920s, the Wooten-Bowden Report was issued, recommending the seaway project.

The Montreal Gazette reported on June 18, 1924 quote:

“The Wooden Bowden report calls for the erection of a series of lift locks and guard locks, deepening the channels, dams, extensive flooding, dykes, control works, embankments, etc to make the St. Lawrence navigable from Lake St. Louis to Prescott by a channel 25 feet deep and varying in width from 200 to 600 feet.”

Prime Minister William Lyon Mackenzie King was reluctant to proceed in the project due to the opposition to it in Quebec. Some also criticized the plan to deepen the St. Lawrence River, stating it would result in high flooding. There was also concern that the flooding would submerge two cemeteries, including one where Sir James Whitney, former premier of Ontario, was buried. The Ottawa Journal stated quote:

“Since the scheme was for the good of a large number of people, Mr. Gardner did not think the cemeteries or the few houses that would be submerged should stand in the way of the great benefit. George Washington had been moved once and if the United States could bear that, Ontario should not object to the removal of Sir James Whitney.”

Despite some opposition, in 1932, Prime Minister R.B. Bennett signed a treaty of intent with the United States for the seaway project. In November 1932, the treaty was submitted to the U.S. Senate and talks continued until a vote was held on March 14, 1934.

The majority of Senators voted for the treaty but they were unable to get two-thirds of a majority for ratifying the treaty and it would fail.

Throughout the 1930s, further attempts at creating a treaty were conducted but now opposition was coming from Premier Mitchell Hepburn in Ontario. Macleans wrote quote:

“Mr. Hepburn didn’t want the St. Lawrence Seaway built. He thought the whole thing a waste of money and quite unnecessary.”

The plan involved Ontario, and without the province, it was not going to happen.

In 1936, the Great Lakes Harbors Association and Great Lakes Tidewaters Commission, along with delegates from eight Great Lakes states met with US President Franklin Delano Roosevelt in order to obtain support for the project.

Two years later, negotiations on the treaty started up again. By this point, Hepburn had said he had a change of heart and was withdrawing his opposition to it and was anxious to start talking about the plan.

In January 1940 an agreement was reached between the two countries. One year later, Roosevelt and King made an agreement to build a joint hydro and navigation works.

Macleans would write that year quote:

“Uncle Sam came back and asked the same old question. This time he had a pretty determined look in his eye. He also had a new reason for doing the St. Lawrence job. The new reason was national defense.”

President Roosevelt seemed eager to get the Seaway built. He would state at the Great Lakes-St. Lawrence Seaway Conference at Detroit, quote:

“The United States needs the St. Lawrence Seaway for defense. The United States needs this great landlocked sea as a secure haven in which it will be able to build ships and more ships in order to protect our trade and our shores.”

This failed to pass the US Congress and neither Mackenzie King, nor Roosevelt, would live to see the day that things finally started to get moving.

On Sept. 28, 1951, Prime Minister Louis St. Laurent and President Harry Truman met and St. Laurent told Truman that the Canadian government stated would construct the seaway completely within Canadian territory. This would spook the Americans, who decided that they wanted to be a part of the project.

On Dec. 21, 1951, the federal government created the St. Lawrence Seaway Authority and Canada endeavored to construct the project alone.

The United States, seeing Canada was going to move forward without them, decided to get moving on a treaty. On Jan. 12, 1953, debate began in the US Senate and a bill emerged from the House of Representatives Committee of Public Works on Feb. 22, 1954. This was approved by the House and Senate in May 1954.

On May 13, 1954, President Dwight Eisenhower signed the Wiley-Dondero Seaway Act to authorize joint construction and establish the St. Lawrence Seaway Development Corporation.

On Aug. 10, 1954, groundbreaking ceremonies were held in Massena, New York. On the American side of the border, Governor Thomas Dewey of New York State pressed a button to set off a dynamite charge to begin work on that side, while Prime Minister Louis St. Laurent moved the first bit of dirt on the Canadian side, along with Ontario Premier Leslie Frost. The Montreal Star reported quote:

“Mr. St. Laurent, after breaking ground, said that the ceremonies had been characterized by the spirit of friendship and harmony which Canada and the US have come to accept as normal. The St. Lawrence River has become a bond rather than a barrier, he said, and the project will bind together all residents of the St. Lawrence Valley.”

One of the biggest projects was the 2,090 megawatt powerplant built near Cornwall, Ontario. The construction of the powerplant came as a mixed blessing for Cornwall. While it was expected to help the city greatly in the future, especially thanks to the $1 million filtration plant being added to the city, there were serveral problems for the city during construction. This was because so many workers were in Cornwall, many living in trailer homes and rented rooms, that there was a housing shortage and rents were high, pushing many families out. Another issue came on paydays when the hydro workers began to celebrate the end of the work week, causing problems for police. Add into the fact that 5,000 visitors a day were coming to the city to see the mammoth construction project, the city was beginning to burst at the seams.

The dam at the western end of the city would also require a reservoir, which caused the flooding of part of Cornwall, resulting in the regional character of the community changing forever as 6,500 people had to be re-located in the area. I’ll talk more about that later.

Everything came to a head July 1, 1958 when 27 tonnes of explosives were used to demolish the cofferdam that had diverted the St. Lawrence River water away from the plant under construction. It would take only four days after this for the plant to become operational and the last generators were commissioned in 1959.

Both countries would have different parts of the project, and for Canada’s part, along with the changes to bridges, there would be five locks built, the Welland Canal would be deepened, 40 to 59 kilometres of canal would be excavated and 97 kilometres of 114 kilometres of underwater channels would be dredged. A 700 metre dam would be built by Hyrdo-Quebec as well that eliminated the 24 metre drop over four sets of rapids. This dam would have 26 generators providing power to Montreal.

There was also an immense amount of bridge and tunnel construction that had to take place. In the first year of construction, 10 dredges were conducted at Lake St. Louis and Lake St. Francis in order to deepen the channel to 27 feet. Even with the winter, a lot of work continued. At Montreal, enlargement of the piers at Jacques Cartier bridge was conducted, and at the future channel at Montreal Harbour, one million of two million yards of material, 25 per cent of which was rock, had been removed. The raising of the Jacques Cartier Bridge was no easy task, as it needed to allow 120 feet in clearance below it in order to allow larger ships to move through. Amazingly, the new higher span was built alongside the old bridge. The bridge was raised over time using hydraulic jacks, and then in the fall of 1957, it was detached and lifted off the place it had sat for so long. At this point, the new span would be lifted and fitted into place. The process would only take two hours. 

The Montreal Gazette would report on the work in 1955 quote:

“This spring of 1955 may seem like just another spring in Montreal but already huge bulldozers and other heavy equipment are about to move onto two projects bordering the South Shore. Last week, the Authority called for tenders for excavation and construction of the Seaway along about 4,900 feet in the river opposite Montreal, extending to the upper end of the present ship channel.”

In Ontario, rivalries between towns began to spring up as they all vied for a share of what the seaway would be providing. The community of Iroquois would be very excited as it would become the commercial gateway to the Great Lakes. That excitement came with trepidation though, as Iroquois was one of the communities that would be partially flooded by the construction. Unlike the Lost Villages as they would come to be called, Iroquois would be relocated.

Both Toronto and Montreal also said they would be the Gateway.

Toronto Mayor Fred Gardiner would say quote:

“Toronto will have a population of two million in 15 years. Nothing can stop us from being one of the most important cities in the world.”

Mayor Lloyd Jackson of Hamilton disagreed, stating that Hamilton’s harbor was bigger and better and with its steel industries it would have the ability to expand.

By the summer of 1956, over $122 million had been spent on the construction, with phase one of the project, the excavation and dredging, well underway and phase two, the evolution of the mechanical works, was just starting.

Many saw the biggest benefit of the seaway was that it would open up a much larger market for Labrador iron ore. Originally, the ore would be shipped to Pennsylvania and then inland through rail. This would come with high transportation costs and the maximum demand for Labrador ore was about 10 million tons per year as a result. With the Seaway, the ore could get into the interior much easier and cheaper, allowing for upwards of 20 to 30 million tons of ore. It was also expected that by 1965, the St. Lawrence Seaway would see more traffic than the Panama Canal.

Macleans would write quote:

“With the Seaway completed there will be no physical barrier to prevent British ocean ships from sailing up the Great Lakes to Fort William and loading grain there.”

The building of the seaway would result in the creation of Lake St. Lawrence, which was formed from the flooding of 15,400 hectares of land. This in turn resulted in the relocation of nine communities, parts of two towns and the rerouting of several highways. In all, 525 homes, 6,500 people, 64 kilometres of railway and 56 kilometres of highway were relocated. A total of 20,000 acres of farmland was also covered by water.

These communities would become known as The Lost Villages. Residents were given market value for their homes, although many felt they were cheated because the Seaway plan had decreased their property values before the government compensated them. Part of the flooded area includes Crysler’s Farm, the location of a major battle in 1812. Today, a few remnants of these villages remain and sidewalks and building foundations can be seen under the water or even along the shoreline when the water level is low.

The Akwesasne would lose 1,200 acres of reserve land and 15,000 acres of traditional land. They were not consulted, nor were they compensated, for the flooding of ten islands that belonged to them. It would not be until 2008 that they would be monetarily compensated.

On April 25, 1959, the St. Lawrence Seaway was opened to traffic. Between Montreal and Lake Ontario, vessels were lifted through a series of locks 224 feet.

The Windsor Star reported quote:

“Opening today to ships from the seven seas, the new waterway has seven steps leading from this riverfront metropolis to land-bound harbours in the five Great Lakes.”

Each lock was 800 feet long, and made of concrete. Each of the locks took the boats away from an obstacle in the river such as rapids or a dam built for power generation. The first step in the journey was entering the Seaway under the Jacques Cartier Bridge, then into 29 kilometres into a canal that contains two locks. The first lock lifts the boat 15 feet, while the second canal lifts the boat 30 feet. Then it is through Lake St. Louis into another channel with two more locks, then into Lake St. Francis and two more locks.

On the first day, 68 ships moved through the Seaway. On the ships were Prime Minister John Diefenbaker, 118 Canadian MPs, 21 Senators and seven US congressmen. The 68 ships stretched 225 kilometres down the Seaway.

On June 26, 1959, the official opening would occur in a ceremony attended by Prime Minister John Diefenbaker, President Dwight Eisenhower and Queen Elizabeth II.

President Eisenhower would say quote:

“May this example be never forgotten by us, may it never be ignored by others. For in the reasonable resolution of the acute international problems of our time rests the single hope for world prosperity and happiness in peace, with justice for all.”

Queen Elizabeth II would say in her speech, which was a mix of French and English quote:

“This partnership is most agreeably symbolized Mr. President, in the fact that you and I have joined together to perform this ceremony today.”

Over 40,000 people attended the official opening of the Seaway. The Sault Star wrote that 300 Roman Catholic church bells, the horns and sirens of 50 freighters, joined the cheers of the crowd to cheer the opening of the Seaway.

The total construction of the Seaway cost $470 million, $336.2 million of which was paid for by the Canadian government. The total cost would be $4.5 billion today. The cost would be mitigated by a toll system that was expected to right off the cost with in 50 years, which would be 2009. Talks would be conducted between the United States and Canada in order to find a system of tolls that would work for both countries.

Through its construction, 22,000 people were employed at one point or another. The opening of the canal then made the Erie Canal obsolete and this caused a severe economic decline in Upstate New York.

Today, the Seaway generates $3.4 billion in business in the United States and Canada. Each year, over 250 million tons of cargo moves through the seaway.

So, was Mayor Gardiner right that Toronto would have a population of two million within 15 years? As it turned out, he was, as by 1971, only 12 years after the Seaway opened, Toronto had 2,089,729 people.

I will end this episode with a wonderful quote by Hugh Maclennan of Macleans, who wrote on May 9, 1959 quote:

“The lower Thames is overwhelmed by London, the lower Hudson is utterly dominated by the towers of Manhattan but when you fly out of Dorval on the London or Halifax plane, the river below you is so enormous that the Seaway excavations look no more than a trivial scar and even the size of Montreal shrinks in your mind. The St. Lawrence is still too big to be dominated in the landscape by anything human beings do to it. Below Quebec there are long reaches of the river which look today exactly as they did to Cartier. Even along the upper river, even along the section of the old International Rapids, where the engineering work of the Seaway and power project has been most spectacular, the changes wrought in the landscape are relatively small compared to the landscape’s vastness.”

Information from Canadian Encyclopedia,, Macleans, Wikipedia, Ottawa Journal, Montreal Gazette, Montreal Star, National Post, Windsor Star, Calgary Herald,

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