Study of the biological environment – Weirs rehabilitation in the Lake Saint-Pierre archipelago

The Department of Fisheries and Oceans (DFO) requires environmental services for the assessment of certain components of the biological environment in the area of the Lac Saint-Pierre archipelago's weirs. Under the Impact Assessment Act (IAA), DFO is required to conduct an environmental impact assessment of the project to refurbish the weirs, to ensure that it does not cause significant adverse environmental effects. Considering the importance of the project and its issues, and despite the fact that it is not a designated project, the assessment of the environmental effects on the components of the environment must be carried out with a scope and rigor similar to the latter, and the level of detail and accuracy of the assessment of the effects on the components of the environment must be adequately documented and supported. In this context, the complementary studies to be carried out must be designed and developed to adequately support the analysis of the project's effects on the Valued Environmental Components (VECs), and to promote the adoption of mitigation measures adapted to the project. Also, in anticipation of the environmental follow-up program that could be developed as part of the environmental assessment, certain parameters need to be measured or inventoried before the project is carried out in order to document the baseline condition. To date, a baseline study based on a literature review has been carried out. This study comprises the following 3 sub-studies: • AECOM, 2020a. Étude de base du milieu physique – revue des informations existantes. • AECOM, 2020b. Étude de base du milieu biologique – revue des informations existantes. • AECOM, 2020c. Étude de base du milieu humain – revue des informations existantes. The basic study of the biological environment will be provided with the resulting contract. If required, the other studies can be supplied on request. In addition, fish habitat characterization and mapping was carried out in 2022. The purpose of this characterization was to document the characteristics of fish habitats upstream and downstream of each of the weirs (local area) in order to provide a portrait of the habitats present and thus obtain a reference state for comparison purposes in the event of any environmental follow-up. The results of this study were used to classify the habitats present according to specific criteria. This information will be provided to the consultant following the awarding of the contract. Complementary characterizations of the environment to be implemented as part of the present mandate must take into account the results of this study in order to define the levels of effort required to establish the use of the habitats of importance that will have been identified.