Updated Watershed Conditions Statement: Flood Outlook – Lake Ontario Shoreline

Updated Watershed Conditions Statement: Flood Outlook – Lake Ontario Shoreline

Posted on May 3, 2019

The Hamilton Conservation Authority (HCA) is advising that Lake Ontario water levels continue to be significantly above normal.  Although there are no observations, reports, or expectations of significant shoreline flooding or erosion at this time, localized flooding of a low-lying section of the Desjardin Recreation Trail has been reported.

According to International Lake Ontario – St. Lawrence River Board information, Lake Ontario water levels are expected to continue to rise over the next 3 - 4 weeks.  Although peak Lake Ontario water levels over this period (assuming average rainfall for this time of year) are not expected to cause significant shoreline flooding hazards, localized flooding may occur in low-lying sections of waterfront trails 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 or east would pose the primary concern.  At this time no significant storm surge and wave action is expected.

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. 

HCA staff continue to monitor Lake Ontario wind conditions and lake levels closely.

Currently, the Lake Ontario water level is approximately 75.55 m IGLD85, which is about 55 cm above average for this time of year.  For reference, this level is about 30 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). 

This Watershed Conditions Statement (Flood Outlook) – Lake Ontario Shoreline is an update to the message issued April 29, 2019.  This updated message is in effect until Friday, May 17, 2019, at which time it will either be updated or cancelled.  HCA will issue updates prior to May 17 as warranted.

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

Jonathan Bastien, Water Resources Engineering

Phone: 905-525-2181 ext 138

Fax: 905-648-4622