Map of swimming potential in Montreal
Plus de 50 endroits où l'eau est de bonne qualité pour se baigner à Montréal
A map revealing the existence of 51 sites accessible from the shores of the island of Montreal where at least 90% of the samples taken by the Réseau de suivi du milieu aquatique (RSMA) show good water quality for swimming in dry weather.
What affects water quality?
Swimming in urban areas is often impossible after heavy rains, which are accompanied by sewage overflows. This affects the quality of the water.
Water contamination during dry weather (when it has not rained for a certain period of time; in the case of our study, 48 hours) is generally caused by cross-connections, i.e., residential or commercial sewer lines connected to the stormwater system. This results in wastewater being discharged into waterways without treatment. The City of Montreal is aware of this problem and is working to address it. Bird droppings can also be a significant source of contamination in some areas.
Where can we swim in Montreal now?
There are only three free public swimming areas in Montreal: at the Verdun beach, at the Parc-nature du Cap-Saint-Jacques and at the Parc-nature du Bois-de-L’Île-Bizard. The City has only three plans to open new swimming areas in the river: at the future Lachine Waterfront Park, at the parc de la Promenade Bellerive and East Beach (compromised by the potential presence of the endangered copper redhorse).
Methodology and details
- Based on data from the City of Montreal's RSMA, collected during the summer months from 2003 to 2021.
- Only sites with a minimum of five consecutive years of sampling, some of which occurred within the last ten years, were selected.
- In Quebec, fecal coliform concentration standards for swimming are set at a maximum of 200 CFU/100mL (Colony Forming Unit).
- Dry weather is associated with a period without rain at least 48 hours prior to sampling.
- The Foundation had hoped to be able to analyze the data in the Laval area, but the City of Laval does not make this information public.
- The data excludes issues regarding water flow and safety parameters.