Photo credit: Louis Rhéaume
Photo credit: Louis Rhéaume

Dredging activities are carried out in the St. Lawrence River to maintain the necessary depth to ensure safe navigation. Dredging operations require the use of specific ships and equipment depending on the type of work and environment.

Extracted sediments are then disposed at sea (discharged in open water, requiring a license issued by Environment and Climate Change Canada (ECCC)) or stored in an approved facility depending on their level of contamination.

Approximately 450 000 m3 of sediments are extracted each year in the Saint-Lawrence. (Source : Recommandations for the management of suspended solids during dredging activities (SS) , St. Lawrence Action Plan 2011-2026)

Dredging operations have an impact on the environment. Sediments at the bottom of the river are heavily contaminated by heavy metals, PCBs and other toxic compounds, as a result of dumping waste into the river during the industrial era.

Because of their impacts, dredging activities are strictly regulated by different levels of government. Despite dredging activities being of federal jurisdiction (involving the Canadian Coast Guard (Fisheries and Oceans Canada), Public Services and Procurement Canada, Environment and Climate Change Canada), those carried out in Quebec may also be subject to provincial and municipal laws and regulations.

The applicable regulatory framework depends on the identity of the proponent, the nature of the work, the preferred method of sediment management and geographic location of the project.

List of applicable laws ruling dredging activities in Quebec: 

Depending on the scope of the work, dredging operations are subject to the environmental impact assessment and review procedure requiring an environmental impact assessment and a public consultation (Regulation respecting environmental impact assessment and review).

In Quebec dredging operations are carried out by following an integrated management approach (Integrated management of dredging and sediments, IMDS). This means that all operations, including management of sediments (contaminated or not) are planned in cooperation with all relevant stakeholders and after analysis of all aspects of the environment (physical, biological, socio-economic, cultural, etc.). The goal is to find optimal solutions to protect the natural environment, considering sediment quality and the expected impacts on the environment, while remaining realistic from a socio-economic perspective.

The list of all current and planned dredging activities can be consulted in the St. Lawrence Dredging Activities Planning Registry.