Lake Ontario Water Levels and Flood Mitigation Update

The City continues to receive updates from the International Lake Ontario-St. Lawrence River Board on water levels in Lake Ontario.

As of April 30, authorities are forecasting lower peak lake levels than we experienced in 2017 and 2019. While lake levels have been high since the beginning of 2020, weather conditions this spring have been dry and cool in both the Lake Ontario and Ottawa River basins. The rapid, heavy spring snowmelt and precipitation experienced during previous flood years have not occurred, and current forecasts indicate these trends will continue. These projections suggest a decreasing likelihood of flood conditions on Toronto Islands this year.

The City will continue to work on flood mitigation projects on Toronto Islands and the waterfront to ensure long-term protection is in place for this season and future years. Lake Ontario water level triggers have been established, and further plans are in place if lake levels rise above 75.5 metres. If this occurs, emergency teams will immediately work to assess impacts and implement flood mitigation plans. This work will continue alongside the Emergency Operation Centre's ongoing work in response to the COVID-19 pandemic.

  • The Office of Emergency Management (OEM) has assigned a response team to focus on the 2020 flood season and coordinate the City’s response with our partners. Emergency response plans are being updated to work under current directives to mitigate COVID-19, and to address needs along the city-side waterfront as well as Toronto Islands.
  • All Toronto and Region Conservation Authority (TRCA) flood mitigation projects for Toronto's Waterfront and Toronto Islands continue to be categorized as "essential" business under the Province of Ontario's recently updated direction. These works are continuing with appropriate public health-recommended separation protocols for workers.
  • On Toronto Islands, the TRCA has completed installation of new flood mitigation beach curbs east and west of Ward’s dock.
  • Urgent raising of roads to maintain emergency access in two priority locations is underway: a 300m stretch of Lake Shore Boulevard near Gibraltar Point, and a 200m stretch on Cibola Avenue near the Fire Hall. The road bed raising work has been completed and asphalting is expected to begin the week of May 18. The roads are fully accessible for vehicles until that work is completed.
  • At the Toronto Island Water Treatment Plant, implementation of two berms, a sump pit, and metre bags is underway to protect this vital public infrastructure.
  • Engineering assessment work on the sea wall at Algonquin Island has been completed. TRCA has recommended implementation of a 1m berm on the sea wall, along the edge of Seneca Avenue. Design work will be completed by mid-May, and construction is scheduled to be completed in June. In the meantime, previously installed metre-bags and new sandbagging will provide protection from wave action.
  • Twelve aquadams and more industrial pumps have been ordered for installation before extreme lake levels are reached to mitigate flooding in low-lying areas of Toronto Islands Park.
  • Technical mapping of flood impacts for different lake level elevations for the whole of Toronto’s waterfront has been produced by TRCA to inform Emergency Management planning. This information will be posted on a public portal on TRCA’s website in the coming days.​