Preparing our communities for flooding caused by climate change

Climate change is accelerating, and this means that "extreme" weather is becoming the new normal. The return of major flooding to the Toronto Islands this year has kept the local consequences of climate change at the forefront of our attention and efforts all spring, but there are also a broad range of actions underway at the City to prepare all our neighbourhoods and communities for a changing climate.

Earlier this month, the Chief Resilience Officer released Toronto's first Resilience Strategy, a plan for comprehensive proactive action. You can download the full strategy here:

For Toronto, long-range predictions for our future weather show that climate change will significantly increase the amount of rain that can fall during summer storms. In other words, instances in recent years of sudden and extreme rainfall overwhelming our local streets and sewers, causing dramatic surface and basement flooding, will become much more frequent and severe. In fact, future storms could drop up to 2.5 times as much rain as the biggest storms today.

Residents who have experienced local flooding in the past few years know that rain storms already have the potential to overwhelm our infrastructure. With climate change accelerating and flooding predicted to become more severe, it is clear that we urgently need to invest in infrastructure upgrades.

Basement flooding study

This summer, the City of Toronto has initiated three parallel Environmental Assessment studies of basement flooding across the entire downtown including every Ward 10 neighbourhood north of the waterfront.

Click here to download the Notice of Study Commencement document.

Similar work has recently been completed for other areas of the City - you can find background information on the project website by visiting You can also sign up to the mailing list for regular updates there.

The basement flooding study will review infrastructure improvement options for the City's sewer and drainage system. Solutions could include new underground storage tanks for stormwater, larger or twinned sewer pipes, and new stormwater management features in parks and roadways.

Public engagement is an important part of the work plan for the basement flooding study. There will be multiple opportunities to ask questions and give your feedback, and regular updates will be provided by the project team. An online survey is now open on the project website where you can share your flooding experiences and issues with the City of Toronto: access the survey, click on the active study area for your neighbourhood.

If you have additional questions or any feedback that is not captured by the online survey, you can email [email protected].

Don River and Central Waterfront Wet Weather Flow System

The City is spending $3 billion to improve trunk sewer and stormwater capacity along the central waterfront and Lower Don River. The first phase of improvements is underway, which will then enable construction of a new 6-metre diameter tunnel parallel to the inner harbour for 5.6 kilometres. The new tunnel will intercept overflows caused by excess rain, preventing stormwater contaminated with sewage from backing up into basements and streets or flowing into the lake. The tunnel will carry this stormwater to new storage shafts and then on to an expanded, upgraded Ashbridges Bay Treatment Plant. In addition to reducing flooding, these infrastructure upgrades will improve water quality in the inner harbour.

City of Toronto staff have assembled a strategy to accelerate the construction of these improvements, subject to funding support from our government partners. With additional up-front funding, it will be possible to have all the new infrastructure in service eight years sooner than planned.

Waterfront Sanitary Servicing Master Plan

The sewer infrastructure plan for serving the rapid population growth south of Front Street to the waterfront, between Bathurst Street and the Port Lands, was updated recently and approved by the Minister of the Environment in March 2019. Approved priority projects include:

  •         Equipment upgrades to the Scott Street Sewage Pumping Station
  •         A new bypass sewer on Scott Street between The Esplanade and Front Street
  •         Upgrade of a sanitary sewer along Yonge Street between Harbour Street and The Esplanade
  •         Upgrade of a sanitary sewer along Lower Jarvis Street under the Gardiner Expressway

Lower Simcoe Underpass Flood Protection Study

The City of Toronto has initiated a focused study to address frequent flooding issues at the Lower Simcoe Street underpass, looking at the local area between Front Street and the lake shoreline. The study will develop a plan to;

  • Prevent the combined sewage overflowing to the street in underpass area from the pipe during rainfall events
  • Identify a location for a storm pumping station to drain the rainwater from the underpass area.
  • Potential modifications to the existing Lower Simcoe Sewage Pumping Station

More information, updates, and public consultation opportunities will be posted on the project webpage.

More work ahead

In the months ahead there will be a lot of activity on the initiatives outlined above, and I am looking forward to working with each community on flood prevention and mitigation, and wider climate change resiliency efforts. There are also many more ways that the City of Toronto, communities, and other levels of government can act on climate change, which are outlined in the new Resilience Strategy. It won't always be easy, as we saw when the majority of City Council rejected a new stormwater runoff fee to be paid by large landowners, which would have helped alleviate flooding issues across Toronto.

In addition, we cannot overlook the ways in which poverty and inequality worsen the effects of climate change. If power is lost in a large apartment tower due to a wind storm or flooding, it makes a big difference whether affected families have adequate individual resources, family and social connections, and local community institutions and services to weather the disruption. I will continue to fight to eliminate poverty, respond to the crises of affordable housing, homelessness and overdose in our city, and work to build a fairer, compassionate, more equitable and resilient Toronto.