Flood Watch for Lake Ontario/Bay of Quinte Shoreline

Lower Trent Conservation advises local municipalities and the public that a Flood Watch 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 significant storm system is occurring across most of southern Ontario today. Heavy rainfall is expected with 25- 50 mm of rain forecasted along the Lake Ontario basin.

Water levels on Lake Ontario are expected to rapidly increase this week and onwards 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 reduced due to the current situation in the Ottawa River and downstream impacts along the St. Lawrence River.

Currently, the lake level at Cobourg is approximately 75.3 metres above sea level, which is 35 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. Strong winds associated with this storm event that will track through today and into tomorrow will bring wave heights in excess of 1 metre. Surge related flooding along the shoreline is possible as well as an increased potential for erosion damages from high waves. Residents should be aware that high onshore winds can result in greater short-term fluctuations of water level. 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, the Flood Warning previously issued for the Trent River on April 22nd, 2019 is still in effect until April 29th, 2019. 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

If you have concerns about water levels, please contact Lower Trent Conservation at (613) 394-4829.

This Flood Watch will be in effect until (or updated before) Monday, May 10th , 2019