August 6, 2019


Under the International Great Lakes Water Quality Agreement there is little mention of the ecological impacts of extreme water levels or the very imminent threat of a Grass Carp invasion from the US side of Lake Erie. The Georgian Bay Great Lakes Foundation would like to bring these two concerns to your attention.

Water levels on all the Great Lakes are now at their historic high levels for the month of July. Shoreline damages are occurring but what most people don’t realize is that Lakes Michigan/Huron/Georgian Bay are suffering the most because there is no control board. We have a 6.5 foot range of water levels while all the other lakes have only a 4-5 foot range. All the other lakes have outflow control boards under the auspices of the International Joint Commission.

The impacts of extreme water levels on Georgian Bay wetlands and the fishery are very significant. We have the most diverse and complex shoreline of all the Great Lakes – from limestones cliff shorelines on the west side, to sand and shale beaches on the south, to the 30,000 Precambrian Shield granite islands on the east and north coasts – with the most extensive, diverse and highest quality wetlands found anywhere in the Great Lakes. During the unprecedented 13 years of extreme low water levels (1999 – 2012), McMaster University’s Professor Pat Chow-Fraser found a 24% loss of wetland habitat for Georgian Bay. The IJC is no doubt aware of the important ecological functions that wetlands provide and maintaining water quality is one of them.

The International Lake Superior Board of Control (ILSBC) operates under the jurisdiction of the IJC. Its mandate includes consideration of the impacts of their decisions regarding the outflow discharges from Lake Superior on BOTH Lake Superior and Lakes Michigan/Huron and Georgian Bay. But it does not appear to do that and in spite of letters from Restore Our Water International (an organization that we at GBGLF are part of) requesting more equitable decisions by the ILSBC there have not been any changes.

Take a look at the June Canadian Hydrographic Services Great Lakes water levels and flows (below) posted June 2019 data. It shows that for June 2019 the water supply into Lakes Michigan/Huron and Georgian Bay was significantly more than double the supply into Lake Superior (306,000 cfs vs 125,000 cfs) BUT the discharge out of Lake Superior via the ILSBC under the auspices of the IJC was increased by 25%. With Lake Superior only having a 4-foot range compared to our 6.5 foot range, whenever levels are low the ILSBC reduces Lake Superior discharges and when levels are high they increase the discharges. Given the ecological and economic impacts of extreme levels on Lakes Michigan Huron Georgian Bay levels, this has to change. We have been requesting changes since 2003. How long does this disparity have to go on? When will there be one control board for all the Great Lakes so that water levels (that impact water quality, wetlands and the fishery) can be equitably managed? Your own 1993 most extensive Levels Reference Study in Annex 6 provided some excellent recommendations on how to deal with extreme water levels. The time is right for the IJC to officially recommend to both Federal governments that they implement the Annex 6 crisis levels proposals.