Toronto Islands Flood Mitigation - May 21st Update

On May 1st, I circulated on update on measures put in place to mitigate high Lake levels on flooding on our Toronto Islands. Experts continue to expect 2017 water levels and I am continually being updated on conditions and mitigation efforts. On May 8th, I attended Toronto Islands with City and Toronto and Region Conservation Authority (TRCA) staff to review flood mitigation preparations. Our staff have worked diligently to ensure measures are in place to protect this important park and community.

I want to share with you the latest information I have received from City and TRCA staff.

Lake Ontario condition

On May 17th, the International Lake Ontario – St. Lawrence River Board (ILOSLRB) advised that Lake Ontario continues to rise as high inflows and reduced outflows continue. A forecast from ILOSRB suggests a 50% chance that within two weeks, levels will reach or exceed the highs of 2017. Above-average inflows from Lake Erie are expected to continue, and given average inflows to Lake Ontario through its watersheds, water levels are expected to continue rising for at least the next few weeks, before reaching their anticipated seasonal peak. Ottawa River flows have peaked a second time and are again beginning to slowly decline. Outflows from Lake Ontario are being increased again as they do.

Toronto Area condition

The Lake Ontario water level at Toronto (24-hour average) is 75.75 metres above sea level (masl). For reference, the maximum observed (daily) water level during the entire Lake Ontario event in 2017 was 75.93 masl for the Toronto area. Given these conditions, it is reasonable to expect similar peak water levels that were experienced in 2017. Once Lake Ontario water levels peak between months end and mid-June, it will then take many weeks to recede back down to normal seasonal levels.

Toronto Islands update

To mitigate flooding on Toronto Islands, a number of initiatives are in place.

TRCA and City of Toronto Parks staff have continued to work to fill and place both small and meter type sandbags. Pumps are pumping where and when as needed, with some pumps running constantly. Extra sump pumps are being installed as needed. City of Toronto Parks staff are now scheduling night shifts to facilitate the continuation of pumping overnight

Two more water dams are being erected at Gibraltar Point.

City staff are creating swales and have developed pumping procedures that will assist in maintaining Centreville access.

Due to the above, ferry service is taking longer due to slower navigational speeds and onboarding/offloading.

City of Toronto and TRCA continue to meet daily to discuss changes conditions and modify plans as needed.

For more detailed information please see a series of links available below:

ILOSRB Website: