The St. Pierre River: Montreal’s Lost River

by Sally Cole

This article was originally published in 2018.  It has been extensively revised, and republished 12/03/2021.

The history of the St. Pierre River is deeply intertwined with the history of Montreal.  The story of the river tells the story of the development of the city itself.  Yet most Montrealers are unaware of its existence.

Long ago rerouted and buried in the city’s sewers and canals, the St. Pierre River is today largely invisible. It is a lost river.

The St. Pierre river in better days

Many cities in the world today are reclaiming and renaturalizing their lost rivers as historic sites, tourist attractions, recreational public parks and biodiverse habitats for plants and animals.  The most visible stretch of the St. Pierre River system remaining above ground today is 200 metres long and nestled in the 57-hectare green space of an ageing golf course in Montreal’s west end. Yet even this vestige of the river may soon be allowed to dry up and disappear.

For millennia, the rich river habitat and wetlands of the Island of Montreal supported the hunting, fishing, foraging and farming activities of Indigenous peoples. When Samuel de Champlain first saw the Island in 1611, he reported that the rivers and streams teemed with fish. Game birds nested. Strawberries, fruit trees and nuts thrived. Montreal Island’s network of rivers and streams gave access to, and shelter from, the strong waters of the St. Lawrence and Ottawa Rivers. Nearby meadows offered fertile soil to farm and provide food for the settlement that de Maisonneuve founded 30 years later as Ville Marie. European settlement grew as the site became a hub in the North American fur trade and a port for lumber export to Europe.

The St. Pierre River is one of more than 30 rivers and streams that once traversed the Island of Montreal.  Originating in streams on Mount Royal, the St. Pierre River flowed via several tributaries through Côte Saint-Luc, Ville Saint-Pierre, Saint-Henri and Verdun. It flowed over the Notre Dame de Grâce Escarpment (now the Falaise St. Jacques), draining the higher ground and widening into a lake below that was called Lac Saint-Pierre or Otter Lake, now the site of the Turcot interchange. The river finally flowed into the St. Lawrence River, across from Nun’s Island.

Diverted Early

In the late 17th century (ca. 1697), the Sulpicians, who in 1657 had been granted the Ville Marie seigneury, built the Saint-Gabriel canal to divert water from the St. Pierre River and increase the flow of water powering their flour mills. The waters of Otter Lake gradually drained. In the 1820s, the St. Pierre River was tunneled under the new Lachine Canal to control erosion.

Eventually, the canalized St. Pierre River joined other streams, including the ruisseau Prud’homme draining NDG and the ruisseau Saint-Martin which drained the Plateau, combining to form the Petite Rivière flowing on the edge of Griffintown, through Place d’Youville and out into the St. Lawrence at Pointe à Callière.  In 1832-38, the St. Pierre-Petite Rivière system was incorporated into the city’s first stone sewer, the William Collector, which can be visited today at the Point à Callière museum.

Throughout the 19th century, the industrializing city straightened, dredged and diverted the St. Pierre-Petite Rivière system as it built the city waterworks, supplied steam engines to drive industry, and developed the urban sewer system. By the mid-19th century, when the first railway yards were built, Otter Lake was little more than a marsh (that nonetheless managed to swallow two locomotives). By the early 20th century, more than one third of the river had disappeared into sewers.

In the 1950s, sewer construction for new housing in the suburb of Côte Saint-Luc covered open sections of the Little St. Pierre tributary, and the Côte Saint-Luc shopping centre was built on a wetland of the original St. Pierre river drainage system. The 200 metres of the old St. Pierre River system that survive today remain because this tributary, the Little St. Pierre, was a key feature of the 57-hectare recreational area that the Canadian Pacific Railway created for its workers after World War I and that, in the mid-20th century, became the Meadowbrook golf course.

In 2006, real estate developer Groupe Pacific bought the golf course for a housing development they called “The Petite Rivière Project.” The company submitted a proposal to the City of Montreal to develop the Lachine side of the site. The plan was to build more than 1600 residential units, keeping the 31 hectares located in Côte Saint-Luc as a nine-hole golf course. The proposal listed five actions as key to create the new Petite Rivière neighbourhood, and action #1 was to “Bring the distressed Petite Rivière stream back to life as a healthy, restored river.” The city eventually rejected the housing development proposal.

Pollution Problems

The river is polluted because of crossed connections between household sewage pipes and storm sewers in Côte Saint-Luc and Montreal West. In its original proposal, the developer stated that Groupe Pacific itself would purify the river through a system of reed beds and shallow ponds to manage rainwater and snow melt and bring back the biodiversity of the river’s habitat for amphibians, birds and small mammals. The regenerated river and wetlands were to become the centrepiece of a park for the new residential community. As a tribute to the vibrant agricultural heritage of the banks of the Little St. Pierre River tributary, the developer also proposed to preserve one of the original farm hedges that still remain on Meadowbrook.

The St. Pierre river in 2020

However, as time passed, Groupe Pacific began referring to the Little St. Pierre River as a smelly “ditch” and sued the City of Montreal, demanding that the “open sewer” be buried.  In June 2018, a Quebec Superior Court Judge ordered the City to stop polluting the river and to clean up the riverbanks.  A month later, both the City of Montreal and Groupe Pacific launched appeals.  The city asked for time to correct the crossed sewer connections in Montreal West and Côte Saint-Luc, citing Quebec’s Environmental Quality Act that calls for integrated water management to prevent the loss of wetlands and bodies of water. The city argued that rehabilitation of the river is part of a larger plan for rainwater management and the maintenance of its green corridors.

Meanwhile, Groupe Pacific also appealed the Superior Court ruling, asking that the judgment be modified to order the city to cut off any flow of water to the property—whether contaminated or not—and not be subject to provincial environmental regulations. In January 2021, the Quebec Court of Appeal ordered the City of Montreal to stop all discharge into the river.

We are now a long way away from Groupe Pacific’s proposal to make the Little St. Pierre River the centerpiece of its real estate development!

Public Debate

Only a few small sections of this historic river system are still visible on Meadowbrook, in Angrignon Park and near the Lachine Canal. Clearly, however, the St. Pierre River continues to play a defining role in public debate about the future of Montreal and the kind of city we want to live in.

Beyond its significance to Montreal’s historical patrimony, the St. Pierre River and its wetlands also play important environmental roles in maintaining biodiversity, preserving century-old trees, offering sanctuary to migrating birds and assisting in the management of rainfall, snow melt and flood control.  For many of us, flooded basements after summer rainstorms are a common occurrence—potent reminders that our neighbourhoods were built on wetlands and over buried streambeds.

Many of the world’s great cities, including Seoul, Paris, New York, London and Toronto, are working to bring back—to “daylight”—their original rivers, streams and wetlands. As climate warming increases the frequency and scale of flood events, these cities recognize that it is crucial to use their underground rivers and wetlands as an economical, clean and natural means to manage increasing drainage problems.  These cities also know that clean streams, rivers and wetlands within their cities add measurable value to real estate and immeasurable aesthetic pleasure, educational opportunities and health and well-being to residents.


Let’s Clean and “Daylight” the St. Pierre River

Let’s NOT allow it to dry up or be buried

Let’s Keep the Brook in MeadowBROOK!


The film Lost Rivers by Montreal director Caroline Bacle explores the phenomenon of daylighting:

Gazette journalist Marion Scott also covered the River extensively in 2009

See also “At the mouth of Riviere St. Pierre during the early stages of Montreal in1700” and “Approximate path of river, circa 1800” in

photos by Nigel Dove and Andy Dodge






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