Flood watch issued for Lake Ontario and upper St. Lawrence

Cataraqui Conservation is warning residents along Lake Ontario and the upper St. Lawrence River that water levels are elevated higher than normal.

Water levels continue to persist, and water levels for Lake Ontario are currently sitting 75.3 m above sea level — that’s nearly 0.5 m above average for this time of year, the Cataraqui Conservation said Sunday.

The record high set for this time of year was 0.35 m in 1973, and above typical summer peak. 

The Conservation says heightened risks may start to develop as levels rise above 75.3 m, including potential shoreline flooding, beach submersion, crawl space and septic system inundation and wave-driven erosion.

The current level of Lake Ontario is about 75 m, which was measured at Brockville.

The International Lake Ontario – St. Lawrene River Board, which manages Lake Ontario outflows at the Moses-Saunders Dam at Cornwall and develops water level forecasts, is forecasting that underseas normal weather and water supply conditions peak water levels of around 75.56 m on Lake Ontario wold be expected in the week ending May 15. 

There remains considerable uncertainty, however, for higher peak levels that are possible if wet conditions happen. 

Publicly available water level forecasts are updated weekly by by ILOSSLRB. 

As water levels increase so does the possibility and likelihood of impacts, especially during periods of active weather.

In 2017, and 2019, when levels rose above 75.8 m on Lake Ontario and 75.5 m on the upper St. Lawrence, significant dock submersions and some localized impacts to dwellings and roads happened. Some these impacts on Lake Ontario start to happen at levels between 75.55 m and 75.7 m.

The lake-wide levels reported in 2017 and 2019 were 75.88 m and 75.92 m, respectively. Daily average peaks measured at Kington were 75.84 m and 75.63 m. And the upper St. aLawrence River saw daily average peaks of 75.57 m and 75.63 m, measured at Brockville.

Widespread flooding is not expected at this time. However, the Conservation says residents in flood prone and low-lying areas should continue to pay attention to wind and wave forecasts for approaching storms with high winds from the southeast, south and southwest, like the one forecasted for April 13 and 14, as these are the conditions when the probability for localized impacts— like flooding and erosion — is increased.

If floods are witnessed and assistance is needed, people are asked to contact their local municipality. Catarqui Conservation does not provide sand bags. However, information about where to purchase sand bags is provided at www.crca.ca/flood.

Residents are reminded that it is the property owner’s responsibility to properly dispose of sand bags and sand, which is considered hazardous waste, and any other debris that may have been deposited along the shoreline.

Any work along shorelines (like placement of fill, armour stone, etc.) will require a permit from Cataraqui Conservation. Residents can call the office or visit the website at www.crca.ca for further information.