People on subway

Ontario Line

A new 15.6-km subway line in Toronto that will run from Exhibition Place, through downtown, all the way to the Ontario Science Centre.

Environmental Impact Assessment Report

The Environmental Impact Assessment Report provides a description of local environmental conditions, potential impacts, proposed mitigation and monitoring measures, a record of consultation, and a description of future permits and approvals that may be required.

Read the full Environmental Impact Assessment Report

Read the Statement of Completion

Read the Notice of Final Publication

Read Appendix B – Part 1: Consultation and Correspondence Record

Read Appendix B – Part 2: Consultation and Correspondence Record

Read Appendix B – Part 3: Consultation and Correspondence Record

Read Appendix C – Ontario Line Profile Drawings

Explore each of the environmental assessment components and read about how we plan to address impacts below.

Potential effects and mitigation measures

Potential effects

Construction

  • Disturbance, displacement, or mortality of wildlife.
  • Removal of/damage to trees, terrestrial vegetation, and wildlife habitat.
  • Introduction or spread of invasive species.
  • Erosion and sedimentation.
  • Reduction in ecological function, habitat quality, and integrity.
  • Removal of/damage to aquatic/riparian vegetation and wetlands.
  • Potential for direct, in-water impacts to fish and fish habitat related to temporary crossing structures for the Don River crossings/bridges.
  • Construction may cause soil erosion and increased surface water/stormwater run-off resulting in changes to stormwater quality and quantity.

Operation

  • Operations may cause soil or water contamination as a result of spills (e.g., grease and/ or fuel) from equipment use during maintenance activities.
  • Operations may cause disturbance or displacement of wildlife during vegetation maintenance activities.

Mitigation measures

Construction

  • Vegetation removal will be reduced to the greatest extent possible and limited within the area affected by construction and maintenance activities.
  • Compensation for tree removals and vegetation will be undertaken in accordance with the Metrolinx Vegetation Guideline (2020) and principles of the Toronto and Region Conservation Authority Guideline for Determining Ecosystem Compensation (June 2018).
    • Temporarily disturbed areas will be re-vegetated using non-invasive, preferably native plantings and/or seed mix.
  • Erosion and sediment control measures will be implemented.
  • A Spill Prevention and Response Plan will be developed for construction and operations.
  • All requirements of the Fisheries Act including those pertaining to in-water works will be met during construction.
  • Sensitive wildlife timing restrictions will be followed for construction activities (e.g., removal of vegetation outside of the breeding bird season).
  • Wildlife exclusion measures will be implemented as required to avoid destruction, injury or interference with wildlife species and their habitat.
  • All requirements of the Endangered Species Act and Species at Risk Act will be met.
  • Floodplain impact assessment will be conducted during detailed design following Toronto and Region Conservation Authority guidelines.
  • A Stormwater Management Plan will be developed prior to construction.

Operation

  • A Spill Prevention and Response Plan will be developed for operations.
  • Vegetation removal will be reduced to the extent possible and limited to the Metrolinx right-of-way.
  • Monitoring and management of trees/vegetation in the rail corridor right-of-way.
  • An Integrated Vegetation Management Plan will be developed.

Read more - Appendix A1 – Natural Environment Report

Land Acknowledgement

Metrolinx acknowledges that it operates on the traditional territory of Indigenous Peoples including the Anishnabeg, the Haudenosaunee and the Wendat peoples. In particular these lands are covered by 20 Treaties, and we have a responsibility to recognize and value the rights of Indigenous Nations and Peoples and conduct business in a manner that is built on the foundation of trust, respect and collaboration. Metrolinx is committed to building meaningful relationships with Indigenous Peoples, and to working towards meaningful reconciliation with the original caretakers of this land.