Lower Trent Conservation advises local municipalities and the public that a Flood Outlook Statement has been issued for Lake Ontario and Bay of Quinte shoreline from Grafton to Quinte West. Residents along the shoreline should be aware of the potential for erosion and flooding.  

A rise in Lake Ontario water levels over the spring has moved the lake to above normal levels for this time of year. Lake Ontario water levels increased to 75.30 metres above sea level by the end of April, an increase of 0.76 m since the start of March. This is in response to significant precipitation throughout the Lake Ontario basin, high inflows from Lake Erie and spring freshet flows from local inputs. Lake Ontario outflows have been adjusted during the spring freshet period. The International Lake Ontario-St. Lawrence River Board (Board) is closely monitoring conditions and adjusting Lake Ontario outflows frequently in accordance with Regulation Plan 2014. The Board began applying the F limit (flood limit) on April 16, 2026, which sets maximum outflows from Lake Ontario based on the water level of Lake St. Louis to limit downstream flooding. As Lake Ontario levels increase, the outflows are increased in consideration of high-water impacts both on Lake Ontario and on the lower St. Lawrence River. 

Currently, the lake level at Cobourg is approximately 75.3 metres above sea level, which is 30 centimetres above the long-term average for April. Although Lake Ontario water levels are above average for this time of year, the observed water levels are currently well below the extreme highs of 2017 and 2019. 

High onshore winds may result in greater short-term fluctuations of water levels, as well as increased flooding and erosion.  

Water levels on the Great Lakes naturally vary, responding monthly, seasonally and annually to a variety of factors. Water levels are primarily influenced by natural factors, including precipitation, evaporation, winds, runoff from rivers or streams and inflow from upstream Great Lakes. The Moses-Saunders Dam, approved by the International Joint Commission in the 1950’s, also provides some control over water levels and flows.  

Lake Ontario typically reaches its seasonal high water level in May/June. Residents living along Lake Ontario and the Bay of Quinte should expect further increases in water levels for at least the next month. 

Residents should ensure personal property (boats, docks, etc.) along the shoreline is secured. Property owners are also reminded that any work along the shoreline (e.g., place of fill, armour stone, etc.) will require a permit from Lower Trent Conservation and should call the office or visit the website for more information.  

Please note, a Flood Outlook Statement was issued for the Trent River on May 1, 2026 and is in effect until May 15, 2026.  

Lower Trent Conservation monitors water levels and weather forecasts closely as part of its flood forecasting and warning program. Daily water level updates are available at www.LTC.on.ca. If you have concerns about water levels, please contact Lower Trent Conservation at (613) 394-4829.  

This Flood Outlook Statement will be in effect until (or updated before) Friday, May 8, 2026 at 4:00pm.  

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