Lake Ontario & St. Lawrence River Watershed Conditions Statement Issued

Published on: 2019/04/24 - in Releases

The Cataraqui Region Conservation Authority (CRCA) is advising municipalities and the public that the Surface Water Monitoring Centre (SWMC) of the Ministry of Natural Resources and Forestry issued a Provincial Watershed Conditions Statement, yesterday at 1:00pm:

RELEASE — The International Lake Ontario – St. Lawrence River Board (ILOSLRB), in their bi-weekly briefing on April 23rd, 2019 reported that:

  • Ottawa River flows increased rapidly over the weekend in response to a major storm system contributing to flooding in the lower St. Lawrence River below Montreal, including levels higher than the peaks seen in 2017
  • Lake Ontario outflows are reduced to mitigate further flooding in the lower St. Lawrence River
  • Lake Ontario’s level rose about 10 cm (3.9 in.) over the weekend to 75.22 masl (metres above sea level) as of April 22nd, which is 28 cm (11 in.) above average.
  • Forecast suggests 50% probability that levels will rise at least 20 cm (8 in.) over the next two weeks, with the potential for greater rise under the wettest scenarios
  • Water levels are expected to stay well above seasonal average values through spring, but to remain well below the extreme highs seen in 2017

The Provincial Watershed Conditions Statement provides advanced notice of high water levels on Lake Ontario and St. Lawrence River. Heightened risks may start to develop if water levels were to rise above 75.30 masl, including potential shoreline flooding, beach submersion, crawl space and septic system inundation, and wave-driven erosion.

The water level measured today at Kingston is currently 75.22 m which is 0.8 m below the Lake Ontario 100-year flood elevation of 76.0 m. The current level of the St. Lawrence River measured at Brockville is 75.10 m. This is 0.7 m below the 100-year level of 75.8 metres in that area along the River. The high water levels seen in 2017 were above 75.8 m on Lake Ontario and 75.5 m on St. Lawrence River, measured in Kingston and Brockville respectively. It was at these 2017 levels that significant dock and boat ramp submersions, and some impacts to dwellings, started to occur.

Staff will continue to monitor ILOSLRB forecasts and SWMC Provincial Statements, and update CRCA messaging as needed. This Watershed Conditions Statement will remain in effect until (or updated before) May 8th, 2019.

For up-to-date Lake Ontario and St. Lawrence River water levels in your area visit the following Fisheries and Oceans Canada links:

(Kingston) – 613-544-9264 for real time water levels

(Brockville) – 613-345-0095 for real time water levels

For further information on the Lake Ontario Watershed Conditions Statement visit

For up to date flooding information, please visit the CRCA’s flood forecasting and information page at

Widespread flooding is NOT expected at this time. However, if you witness flooding and/or require assistance your first point of contact is the local municipality.

Release source:
Photo: Wikimedia Commons (pd)