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Chambly Basin – Monitoring water quality and detecting sources of pollution

Chambly Basin – Monitoring water quality and detecting sources of pollution

A step towards safe swimming in the Chambly basin

The Fondation Rivières carried out a study on the bacteriological quality of the water of the Richelieu River. The objective: to assess the swimming potential around the Chambly basin. The Foundation also sought to identify sources of contamination that could harm the opening of swimming sites and the safe practice of non-motorized water activities, such as kayaking, canoeing or paddleboarding.

The Chambly basin, at the Gervais-Désourdy nautical center. Photo: Fondation Rivières


  • Validation of bathing potential
  • Site vulnerability assessment – bacteriological water quality
  • Continuous monitoring of water quality
  • Screening for main sources of pollution

Partners and collaborators

  • City of Chambly 

Our methodology

Regular tracking sites
Testing sites

The Fondation Rivières in collaboration with the municipal team from the Gervais-Désourdy Nautical Center carried out regular water sampling at high frequency. The Foundation also conducted screening tours.

The samples were taken at the Nautical Center wharf as well as at the municipal wharf. They were analyzed by countingEscherichia coli (E.coli) traditional at the Eurofins Environex laboratory. This regular monitoring resulted in a total of 41 days of sampling, making it possible to determine the quality of the water at the sites studied and to establish contamination trends.

The 6 main stages

The sampling took place over a period of 14 weeks, between June and September 2022.

  • June 1 – First field visit and training of the Nautical Center team to participate in sampling
  • June 6 – Start of regular monitoring
  • June 28 – Start of screening
  • August 25 – End of regular monitoring
  • September 10 – Screening of the stormwater network and end of screening
  • November 24 – Submission of the report to the City of Chambly



In summer and in dry weather, the water is generally suitable for swimming and non-motorized water activities.


Four dry weather contamination events were identified, along with their probable causes.


The presence of cross connections is suspected. The City of Chambly identifies them as a priority for intervention.

A strong swimming potential is confirmed in the Chambly basin.

An exceptional collaboration which allowed the City of Chambly to target its environmental interventions

Thanks to this study, the Fondation Rivières confirmed a good swimming potential, despite several contamination peaks during rain and dry weather in the Chambly and Richelieu area. In order to improve the quality of the water in the basin and safe access to swimming, the City of Chambly has integrated the recommendations of the Fondation Rivières into the priority interventions for the year 2023. Monitoring the quality of the Water will be continued at the Nautical Center to ensure the safety of users, in addition to the awareness and monitoring efforts put in place to preserve this resource.

Do you make decisions within your municipality?

Consult the guide to opening an urban swimming site to find out how the Fondation Rivières can help you.

Plage de Verdun
Verdun beach in summer 2021

Our water quality monitoring mandates

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