Environmental assessment for the Ontario Line – A thorough review

This image shows how landscaping could be used to enhance space near the existing rail tracks, next to Jimmie Simpson Park. The exact location, height and design will be confirmed as planning work continues. (Metrolinx image)

As the Ontario Line proceeds through its environmental assessment (EA) process, experts are looking at potential effects on the environment, investigating and suggesting ways to limit them, and considering feedback from residents before a single shovel hits the ground for any proposed work. EAs are a critical step in all major infrastructure projects and the Ontario Line is certainly no exception. This process gives local residents a voice, as the new line is planned and designed to fit into the communities it will serve.

New rail lines change their surroundings.

While additional transit options are always a welcome change, the infrastructure and the operations that support them take some getting used to. That's why – before shovels can go into the ground – plans are designed to keep community impacts to a minimum while striving to offer maximum benefits.

The environmental assessment (EA) process provides a foundation for this important work.

"The EA process ensures that any potential environmental, economic, social and cultural effects that may occur during the lifetime of a major project are thoroughly assessed," said Carrie Sheaffer, Metrolinx Senior Manager, Environmental Programs and Assessment. "It ensures that regulators and public bodies review and consider thorough assessments before construction can begin on an infrastructure project."

This creates an opportunity for the public to get involved.

"A big part of the EA process is the consultation," Sheaffer said. "Engaging and obtaining feedback from ministries, Indigenous communities and members of the general public is integral to the process with requirements clearly spelled out in our EA regulations."

"Residents are consulted throughout and given opportunities to comment. That feedback is very important, we carefully consider it and appropriately address the comments we receive."

"Our team will figure out what works best to mitigate noise and vibration while also fitting seamlessly into the project." Carrie Sheaffer, Metrolinx Senior Manager, Environmental Programs and Assessment

Metrolinx News has already reported on how feedback from the first round of open house meetings in early 2020 is being applied to the Ontario Line design.


The EA process reviews a broad range of impacts.

"Typically, you look at the natural environment as one aspect and there is also the built environment," said Maria Zintchenko, Metrolinx Project Manager for Ontario Line EAs. "It also includes factors such as community amenities, traffic patterns, cultural heritage, archaeology, infrastructure and utilities.

"You get a comprehensive view of how a project fits into that environment, what the impacts are, and how to lessen those impacts. This makes for an all-inclusive assessment."

There are unique challenges to consider before building transit lines in a densely populated city like Toronto.

"We know the longstanding history of the city and its buildings," Zintchenko said. "The built environment and cultural heritage are important in Toronto, and everywhere."

Of course, one issue presents a natural first question for people that live along a proposed transit line.


"Noise and vibration is also an important factor," she noted.

Starting with the use of proven track and vehicle technologies that meet high standards, Metrolinx has a wide range of tools available to address noise and vibration along the route.

This image shows how landscaping could be used to enhance space near the existing rail tracks, next to Jimmie Simpson Park. The exact location, height and design will be confirmed as planning work continues. (Metrolinx image)

Metrolinx has determined that noise walls will be installed along the existing GO rail corridor through Riverside and Leslieville area. Metrolinx has already begun studying projected noise and vibration levels along the Ontario Line. Early study results show that a noise wall in this area will not only be effective in significantly reducing noise from the Ontario Line, GO Transit and VIA Rail trains, but will reduce noise below what it is today at many locations along the corridor.

Wherever possible, noise walls will be surrounded by trees, plants and attractive landscaping to enhance the appearance of the space for the community. This approach will soften the appearance of noise walls that will shield the area from the new Ontario Line as well as existing GO and VIA services.

Final noise wall designs will be subject to future studies as well as robust consultations with the City of Toronto and local community as part of the EA process.


Noise walls will not be the only part of the plan.

The toolkit also includes options such as rail dampers, continuously-welded rail, ballast mats, floating slabs, resiliently supported rail ties and highly resilient fasteners. All of these have been proven effective on transit lines around the world.

"Our team will figure out what works best to mitigate noise and vibration while also fitting seamlessly into the project," Sheaffer said.

An EA is required for all large-scale infrastructure projects that could impact their surroundings. For transit projects across the province, they are required to follow a process set out in a regulation in order to proceed. This requirement is set out in the Transit Project Assessment Process (TPAP). . Certain projects that have more predictable impacts, and are more readily managed, can follow a streamlined approach. This still protects the environment, and shortens the timeline for commencement, review and approval.


On June 30, 2020, the Ontario Government approved a regulation that outlines a new, streamlined EA process for the Ontario Line. The regulation will help get this transit line constructed efficiently, economically and transparently while maintaining strict environmental oversight.

"The new regulation for the Ontario Line prescribes a very similar approach to what we are used to seeing in the TPAP, with requirements for similar studies and reports," Sheaffer said.

It largely follows the existing TPAP process, except that it has added flexibility. This allows for more certainty in project planning, reduces the risk of delays, and still ensures strong environmental oversight alongside consultation at various stages of the design and procurement process for the project.

Protection of the environment will remain a priority as Metrolinx works to deliver transit relief.

Metrolinx is conducting several detailed environmental assessments along the route of the Ontario Line and will be preparing comprehensive reports on how to address and mitigate potential impacts. They will look at issues like noise and vibration, heritage and the natural environment, to name just a few. Metrolinx will consult on all findings, capture public feedback and address it in final reports before any related construction work begins.

The Environmental Conditions Report was the first in the series of EAs for the Ontario Line, and was finalized in September 2020. It explored the existing environmental conditions along the entire route of the Ontario Line and surrounding areas, along with an initial understanding of potential impacts and possible solutions.

The Early Works Report for Exhibition Station has also been completed, with additional Early Works Reports to follow covering other areas of the line, including reports for the joint rail corridor through Riverside and Leslieville as well as the Lower Don Bridges. This allows consultations to start for smaller tasks that can be completed before the main construction begins. These include station modifications, bridge work, existing rail corridor improvements and utility relocations.

As these early works reports are prepared, work is underway for a more detailed, overarching Environmental Impact Assessment Report that will provide a full analysis of impacts and mitigation measures.

Keep reading Metrolinx news – and visiting MetrolinxEngage – for details on the next round of public engagement on the Ontario Line, which will include EA consultation and other opportunities to learn about the project and provide feedback.

Story by Mike Winterburn, Metrolinx Senior Advisor

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