Sarah Delicate from United Shoreline Ontario (USO) shared with us this letter from Mike French, a licensed Professional Engineer:

Hi Sarah,

I’m a resident of the Toronto Islands and have been on the forefront of our battle with high lake levels and flooding. I have written a couple of mitigation reports for the City of Toronto and the Toronto Regional Conservation Authority specifically targeting the Toronto Islands. 

Your group might be interested in my most recent report (attached) that forecasts flooding next spring. I have been studying the lake data and have looked at 5 different forecast scenarios through to Dec 2020. Even if we have an average year next year, it looks like we will have more flooding, unless the IJC increases the outflows until Dec.

I’m starting to share this document with other groups and would love any feedback to pick apart or substantiate my findings.

Best Regards,

Mike French, P.Eng.

11 Channel Ave.

Toronto, ON

Great Lakes Forecast from Oct 2019 – Dec 2020 

Conclusion: All of the Great Lakes are experiencing higher RNBS due to climate conditions. The combined RNBS contribution to supply in the upper Great Lakes will keep a continuous high inflow into Lake Ontario at least through 2020.

The IJC is following the Plan 2014 regulation for Lake Ontario and have started to reduce outflow through the Moses-Saunders Dam to match the prescribed L-limit flow, but this flow will not drop Lake Ontario enough to compensate for the spring change in supply. If the upper Great Lakes levels were close to their historic average and next spring’s RNBS is somewhat average, then the system L-limits will work, but the current formula fails to take into consideration the flow potential of the upper Great Lakes.

From the Plan 2014 Compendium Document: “The Board may also use the information acquired through the adaptive management strategy to propose to the Commission modifications to the plan should it learn over time that conditions (climatic, socio-economic or environmental) have changed enough such that the plan is no longer meeting its intended objectives or improvements to the plan could realize increased benefits.”

This is a case where the Board must intervene and modify the flow limits to reduce the Lake Ontario levels down to ideally 74.5m before the next cycle begins, otherwise the lake will be faced with another catastrophic flood in spring 2020.

74.5 meters = 244.4226 feet , or 74.5 meters = 244.4 feet