Updated Watershed Conditions Statement (Flood Outlook) – Lake Ontario Shoreline

The Hamilton Conservation Authority (HCA) is advising that Lake Ontario water levels continue to be significantly above normal, due to record inflows from Lake Erie and continuing flooding in the St. Lawrence River.  Although there are no observations, reports, or expectations of significant shoreline flooding or erosion at this time, localized flooding has been reported of low-lying sections of the Desjardin Recreation Trail and Cootes Paradise.  In addition, localized flooding of low-lying sections and/or localized shoreline erosion has been reported along waterfront trails in the Confederation Park and Beach Blvd areas.

According to International Lake Ontario – St. Lawrence River Board information, Lake Ontario water levels are expected to continue to rise over the next 2 - 3 weeks.  Peak Lake Ontario water levels over this period (assuming average rainfall for this time of year) are forecasted to reach similar levels to May 2017 record levels.  In of itself, peak lake levels are not expected to cause significant shoreline flooding hazards, although continued localized flooding is expected in low-lying sections of waterfront trails, Desjardin Recreation Trail and Cootes Paradise which are susceptible to flooding at elevated Lake Ontario levels.  

However, significant shoreline flooding and / or erosion hazards are possible in the coming weeks, if substantial storm surge and wave action occurs.  Strong shore-bound winds occurring from the north, northeast, or east would pose the primary concern.   

Based on current forecasts, no significant storm surge or wave action is expected over the next five days.  

HCA wishes to remind residents to exercise caution near lakefront areas during this time, as high water levels and / or wave action may pose significant erosion, flooding and public safety hazards.   

A close watch on shoreline and weather conditions is recommended.  HCA staff continue to monitor Lake Ontario wind conditions and lake levels closely. Currently, the Lake Ontario water level is approximately 75.73 m IGLD85, which is about 70 cm above average for this time of year.  For reference, this level is about 15 cm lower than the peak water level of 75.88 m recorded in May of 2017. 

For additional reference, the HCA shoreline flooding hazard level used for planning and development review is 78.5 m (which includes a lake level of 76.00 m and 2.5 m of wave action).  Lake Ontario water levels are expected to peak and begin to decline within the next few weeks, but will remain very high into the summer months.  
This Watershed Conditions Statement (Flood Outlook) – Lake Ontario Shoreline is an update to the message issued May 3, 2019.  This updated message is in effect until Friday, May 31, 2019, at which time it will either be updated or cancelled.  HCA will issue updates prior to May 31 as warranted.

For further information or questions regarding this message, please contact:

Jonathan Bastien, Water Resources Engineering
905-525-2181 ext 138
Fax: 905-648-4622