Flood Warning (Lake Ontario/Bay of Quinte)

Lower Trent Conservation advises municipalities and the public that the Flood Warning for Lake Ontario and the Bay of Quinte issued on May 9th, 2019 is still in effect.

Water levels on Lake Ontario increased through the months of April and May to reach record levels in the month of June. Over the past week or so the water levels have stabilized and are expected to slowly begin to decline. High water levels on Lake Ontario can be expected well into July.

Record high outflows from Lake Ontario are being managed by the International Lake Ontario St. Lawrence River Board (ILOSLRB) to try to lower the Lake Ontario water levels to provide relief for shoreline owners. The ILOSLRB consider the effects of these high flows downstream in the St. Lawrence River, where flooding is still occurring. Outflows from Lake Ontario have been at 10,400 m3/s since June 13.

The water level measured at Cobourg is currently at 75.90 masl (metres above sea level) which is 20 cm above the Lake Ontario 100-year flood elevation of 75.70 masl and 2 cm above the previous record level from 2017.

Forecasts by the ILOSLRB indicate that the water levels in Lake Ontario are not expected to rise further and will likely continue a slow decline over the coming week under most scenarios. The water levels will continue to decline in general through the summer, with the rate of decline largely dependent on rainfall. Surge related flooding and erosion damage from high waves is possible during periods of strong onshore winds. Residents should pay close attention to weather forecasts for approaching storm systems with high southeast, south or southwest winds. There are no wind warnings in effect at the time of the writing of this bulletin.

Property owners are also reminded that any work along the shoreline (e.g. placement of fill, armour stone, etc.) will require a permit from Lower Trent Conservation and should visit the website ( for more information.

Residents living in low-lying, flood prone areas should take actions to protect themselves and their property. Homeowners affected by flooding should also be aware that electrical, well and septic issues may exist. The public should pay attention to Health Unit guidelines to ensure safe drinking water.

Lower Trent Conservation monitors water levels and weather forecasts as part of its flood forecasting and warning program. If you have concerns about water levels, please contact Lower Trent Conservation at (613) 394-4829.

An update to this Flood Warning for Lake Ontario/Bay of Quinte will be provided on, or before, Friday, July 5th 2019. Additional statements will be issued if conditions are expected to change significantly from this outlook.

A Flood Warning is issued when flooding is beginning/occurring or when more serious flooding is possible. A Flood Warning requires action that may include the activation of the municipal flood emergency plan, warning residents or businesses in specific affected areas, and in some cases evacuation.