Quality of the lake water

Several measures have been taken since the beginning, in order to protect the quality and the health of the lake, but constant involvement is required.

List of initiatives related to the health status of the lake

This page is available on the website petitehistoiredulacmercier.ca

eau1Quality of lake water and protection of the lakebed

The association du lac Mercier is very active in the following projects:

  •  Participation in the Volunteer Lake-Monitoring Program   (VLMP)

Program in cooperation with the Ministry of Long-term Development, Environment and Parks, and with financial support from the City of Mont-Tremblant.

What is Voluntary Monitoring of Lakes Program (VLMP)?


Comparative results since 2009:


An environmental study of lac Mercier, commissioned by the Board of directors of ALM with the support of Ville de Mont-Tremblant, was carried out in 2021 by OBV-RPNS:

   Executive Summary of the Environmental Study of lac Mercier:


Rapport d’étude lac Mercier- Ville de Mont-Tremblant 2018

  • A program was launched in 2022 to eradicate the water milfoil from the lake, and continued this summer.
Jean-Louis Courteau 2023

Read the Diver report- August 2023:

Jean-Louis Courteau 2023



  • Identification of the main species of invasive plants present in the lake:

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Invasive Plants Description:

Eurasian water milfoil: Because of it’s rapid growth, from the first days of Spring, Eurasian water milfoil create dense mats producing shade that inhibits the growth of other submerged plants. Eurasian water milfoil’s mats are known to become so dense as to displace all other plant species. (Environnement Canada, 2003).

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 guide available:
Filtration marsh
  • Storm sewer

During Summer 2012, the municipality has completed repair work on the storm sewers of the village streets, and the lac Moore stream, both of which now flow into a drainage filtration pond near rue Plouffe. Evaluations of efficacy will be done on a regular basis.


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During Summer 2017, we observed that the filtration marsh on chemin Plouffe was filled with sediments from water drainage, occurring over several years. The marsh filled with sediments no longer fulfills its filtration function. Water originating in lac Moore and the storm sewers now flows directly into lac Mercier.

The marsh has been abandoned, and no funds for maintenance have been budgeted since 2017 by the city of Mont-Tremblant. Consequently, the filtration marsh will not be emptied of sediments, and the plants will not be replaced.