Saint-Ours Canal National Historic Site of Canada

Natural Wonders & Cultural Treasures

A close-up look at nature

île Darvard.
© Parks Canada / Jean Mercier / 2002

The Saint-Ours heritage canal runs along the eastern bank of the Richelieu River, about 23 km upstream from the town of Sorel.

The site's location in the eastern part of the mildest climatic region in Quebec is reflected in its climate . The site's geology is similar to that of the surrounding area. A cross-cut of the ground at this spot would show sedimentary bedrock dating from the Ordovician era. The various different geological periods account for the site's characteristic geomorphology, namely smooth landform with few relief features. The soil consists mainly of a silty clay surface deposit dating from the Champlain Sea period, covered with recent reworked alluvium. A means of bypassing the lower shoals of the lower Richelieu River, the Saint-Ours Canal is part of the Richelieu River catchment area. The hydrology of the site therefore closely resembles that of the Richelieu River, both as regards to the water's physico-chemical properties and man-made impacts.

All these abiotic factors combined with the effect of human settlement have resulted in a distinctive flora and fauna along the Saint-Ours Canal. Although the site features most of the species belonging to the sugar maple-hickory stand climate, the tree stratum is clearly dominated by transitional species with low shade tolerance, like the red ash and red pine. With its many visitors, this site is not an ideal habitat for fauna, except for species highly tolerant of man's presence. However, because it is on a main migration route, many different birds can be seen here. The Saint-Ours dam constituted a major obstacle for the free circulation of fish in the Richelieu River. Since the opening of the Vianney-Legendre Fish Ladder many species of fish can now transit freely upstream.

Along the water

The old mill and the entrance of the lock seen from the East in 1907.
© Parks Canada / 1907

The construction of the canals in Quebec reached its peak in the 19th century.

For over 100 years, these canals would play an important role in the economic development of Canada.

Go through the lock of history and travel Quebec's Historic Canals to find out how our country was built!

• Gateway to the St. Lawrence
• How Locks Work

Gateway to the St. Lawrence

Opened in 1849, the Saint-Ours Canal and dam are the final section of the Chambly Canal, allowing boats to avoid the last hurdle between Lake Champlain and the St. Lawrence River. As the final link in the Richelieu Canal system, this canal was essential to the development of regional, national and international trade, which used this waterway for over a century.

Barges waiting next lockage in 1907.
© National Archives of Canada / PA-085652, 1907

In 1829, the government of Lower Canada appointed commissioners to direct work on the Chambly and Saint-Ours Canals. Financial, administrative and political setbacks delayed the start of construction on the Saint-Ours Canal until 1844, a few months after the Chambly Canal was opened. The Saint-Ours dam and lock were finally finished in mid-September 1849.

Towards the middle of the 19th century, to combat the over-stripping of Vermont's forests, the Americans started importing wood in large quantities. The Richelieu River carried hundreds of barges laden with wood from the Ottawa and Saint-Maurice Valleys. In exchange, boats carried, among other things, Pennsylvania coal to Saint-Jean-sur-Richelieu, Sorel, Montréal and Québec.

Regional trade also benefited from the Saint-Ours Dam and Canal. Thanks to the lock, low-water season was no longer a problem: parishes upstream from Saint-Ours could now send their agricultural produce to Sorel and the towns and villages along the St. Lawrence River.

Like the Chambly Canal, the Saint-Ours Canal played an increasingly important role until the beginning of the 19th century, to which the Canadian-American business era was at its height on the Richelieu River.

Afterwards, train companies competed even harder against them. In 1918, Americans invented the Barge Canal System whose larger locks allowed for bigger boats. Canadians tried to match the dimensions of the new American canals with the Richelieu canals.

Construction work of the present lock in Saint-Ours in 1931.
© Parks Canada / 1931

The current Saint-Ours lock was built from 1929 to 1933, Westward of the first one. However, the Chambly Canal was never completely widened, limiting commercial navigation. The canal kept losing customers to the railroad industry and trucks companies.

Around 1965, the old wooden dam, built in 1849, was deemed too damaged to efficiently regulate the Richelieu's water level. A new dam was erected in 1967 using a technology then unique in North America: water pressure, not electricity, controlled the floodgates.

The Superintendant's House.
© Parks Canada / Jean Mercier / 2002

But there are still signs of the old structures: the remains of the old lock, of which only the northeast entrance is visible, as well as the superintendent's house, date from the golden age of commercial navigation on the Richelieu River.