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Adopt a river - Rivière des Mille-Île (Thousand Islands River)
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River Thousand Islands

Photo credit : André Chevrier

Adopt the Mille Îles River to:

Your contribution allows our team to continue to protect Quebec's rivers.

The Mille Îles River is a sanctuary of peace a stone’s throw from Montreal. It weaves between Laval and the North Shore as well as among the hundred or so islands that populate it before joining the Prairie River and the St. Lawrence River. A true cradle of biodiversity, the Mille Îles River nevertheless faces some challenges.

Do you know the Mille Îles River?

Name Abenaki

Makigôtekw (“the river of rakes”)




Lake of Two Mountains


Laurentides, Laval and Lanaudière

Average flow

286 m3/s

Total elevation


Protected areas for rich biodiversity

The Mille Îles River is a place teeming with biodiversity: there are more than 65 species of fish there, including the copper redhorse, an endangered species. Two protected areas are built on the river: that of the Île-Garth ecological reserve, whose existence aims to protect endangered tree species, and that of the Parc de la Rivière-des-Mille-Îles , whose mission is to protect the river and its tributaries, among others.

This wildlife refuge, which shelters nearly a hundred threatened species, should see its surface area multiplied by 20, in accordance with the wish expressed by the City of Laval. That said, even outside these official protection zones, it is teeming with life. This is the case of Miller Marsh, in Rosemère, which acts as a refuge for several endemic species of turtles, birds, insects, amphibians and aquatic plants.

Inhabited islands

Malouin, De Mai, Morris, Ducharme, Bélair, Jean: a good half dozen islands are inhabited. Attractive for real estate developers, Île aux Vaches and Île Saint-Joseph are the most coveted. Although they represent a little paradise on earth, it is essential to preserve the natural character of these jewels, which are home to numerous wetlands and which, in turn, serve as habitats for many species. Luckily, the group Let's save our three big islands ensures their protection and curbs real estate development.

Photo credit : André Chevrier

What are the challenges of the Mille Îles River?

Water quality 

Like several rivers near Montreal, the Mille Îles River is a recipient of wastewater from multiple overflow structures. The Rivière aux Chiens, one of the many tributaries of the Rivière des Mille-îles, suffers from heavy fecal contamination linked to numerous domestic wastewater spills. Some agricultural industries also emit a significant amount of contaminants such as nitrogen and phosphorus.

The Fondation Rivières evaluated the performance of municipal wastewater treatment works twice rather than once in the territory of the Mille-Îles Watershed Council (COBAMIL) to identify the problems. Most recent assessment allowed us to see an improvement in phosphorus removal in certain problematic areas, following the first study

Since 2020, the Fondation Rivières has disclosed the list of municipalities that stand out in terms of the intensity of their wastewater discharges into waterways, including the Mille Îles River. This exercise makes it possible to distinguish municipalities which have improved their situation in previous years from those where the situation has deteriorated. THE prize list serves as a lever to encourage elected officials to make the necessary corrections to improve the health of the rivers into which wastewater is discharged.

Sustainability of natural character

The natural character and ecosystems suffer from real estate development, which accentuates the permeability of the islands' soils. This has the effect of increasing the phenomenon of rainwater runoff, which can lead to water contamination.

The Fondation Rivières provided its support to the Laval Regional Environmental Council (CRE) and citizen groups with the aim of protecting Gagnon Island, targeted by a real estate developer, in the Sainte-Rose sector. She participated in the Leave our island alone demonstration, organized by Vigile Mille-Île, which was held in 2020, and which bore fruit.

Photo credit : André Chevrier

Bank erosion

The banks represent an excellent natural barrier to pollution. However, nautical activity increases their crumbling, which creates problems of sedimentation and siltation. The flooding experienced by the Mille Îles River in the spring also contributes to bank erosion, which in turn has an effect on water quality.

The Fondation Rivières went note the state of the municipal banks of Laval in the summer of 2022. The objective: based on its observations, challenge municipal elected officials to develop the banks with respect for the environment within the framework of COP15. Adequate development allows, among other things, to reduce the transport of sediment generated by rain runoff towards the river, in addition to serving as a natural habitat for aquatic fauna – promoting healthy biodiversity. 

Providing access to water for everyone

There were once several beaches for swimming in the Mille Îles River, notably those of Idéale, Jacques-Cartier and Barbe (today named Berge Camille-Barbe park), in Laval. However, they had to be closed due to the quality of the water. Today, the Parc de la Rivière-des Mille-îles itself affirms: “ the river is considered swimmable in several places at certain times ". Although this park allows you to navigate by pedal boat, paddle board and many other types of boats, you cannot swim there. Outside the boundaries of the park, there is only one public and free access to swimming in the Mille Îles River: Berge aux Quatre-Vents beach.

The Foundation created a map of swimming potential in Montreal and Laval. Without resorting to sampling, the Foundation instead used existing data on the water quality of the river, the Rivière des Prairies and the Mille Îles to raise awareness among the public and elected officials of the issues that affect the water quality (e.g. reverse connections, wastewater overflows, etc.) and which limit swimming in the Mille Îles River.

Can you swim in the Mille Îles River? 

Berge aux Quatre-Vents beach offers free public access to swim in the Mille Îles River. The City of Laval ensures that water quality is monitored and that lifeguards ensure the safety of swimmers during surveillance hours.

Help us by adopting the Mille Îles River

The Fondation Rivières is mobilizing on this river to:

Donate and join an important mobilization movement!

Charity receipt

Fondation Rivières issues tax-deductible donation receipts, regardless of the amount. A receipt will be sent to you by email at the beginning of the year following the year of your adoption.

Organizations involved in the field

The Mille Îles River was adopted by:

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