05-May-2023 05-May-2023

A Flood Outlook Statement is being issued for areas along the St. Lawrence River shoreline in the South Nation Conservation (SNC) jurisdiction. According to the International Lake Ontario – St. Lawrence River Board, Lake Ontario’s water levels are above average for this time of year and are likely tocontinue increasing as a result of significant rainfall received this past week.

Environmental Conditions:

Lake Ontario levels have been rising at a rate of approximately 1-1.5 cm per day and have reached 75.32 m. On May 4th, levels were forecasted to continue rising and are expected to reach a seasonal peak in the next couple weeks.

The International Lake Ontario-St. Lawrence River Board is closely monitoring the situation. The Lake Ontario outflow into the St. Lawrence River continues to be adjusted in accordance with Plan 2014 with daily flow adjustments to consider upstream and downstream conditions.

In addition to high Lake Ontario levels, outflows from the Ottawa River and other tributaries into the St. Lawrence River have also increased substantially in the past several days due to the widespread major rainfall. 

At this time, the water levels of Lake Ontario and the St. Lawrence River are expected to remain above long-term averages but below the record-highs observed in 2017 and 2019.


Levels in Lake Ontario influence levels in the upper St. Lawrence River, particularly from Kingston to Iroquois, including Maitland, Johnstown and Cardinal.

Increasing water levels may cause flooding along the shoreline or in low lying areas.

Residents are advised that strong winds may cause waves, further increasing water levels.

ACTION: Residents are advised to stay away from watercourses where flows are high and where banks might be unstable. Parents are encouraged to explain dangers to children and provide appropriate supervision around all waterbodies.

Residents in flood prone or low-lying areas, historically susceptible to flooding, should take the necessary precautions to protect their property. Please ensure:

  • Sump pump is clear, in good working condition and has a backwater valve on it.
  • Easy access to portable backup generator and pump.
  • Downspouts are clear and the outlet is at least 3 m from the dwelling.
  • Driveway culverts are clear of debris and drain well.
  • Securing items that might float away as flows increase.


This flood outlook statement is in effect until May 19, 2023 at 5 PM or until an update has been issued.

SNC monitors the water levels and weather forecasts as part of the Flood Forecasting and Warning Program. Updates are provided as conditions change.

The International Lake Ontario – St. Lawrence River Board continues to monitor conditions on an ongoing basis. Information on hydrologic conditions, water levels and outflows, including graphics and photos, are available on the Board’s website at All water levels are referenced to International Great Lakes (Vertical) Datum 1985.

Please visit for more information. To provide feedback with respect to changes in water related conditions please email, post on our Facebook (/SouthNationConservation) or Twitter (@SouthNationCA).

FOR MORE INFORMATION: Jason Symington, Water Resources Specialist – Engineering, 1-877-984-2948,

Forwarded to:  All Flood Forecasting and Warning Directory