Greenough Harbour Community

The GHPA Board Minutes for the Apr 5 2023 meeting are now available under the Resources tab.

IJC Great Lakes Water Level Study – Apr 15 2013

An interesting study was released recently regarding the water levels on the Great Lakes. The study was by the International Joint Commission and was a report that was provided to the governments of Canada and the United States.

Between 1963 -2007 the decline in the water levels of Lake Michigan-Huron relative to Lake Erie of 23 centimetres (cm) or 9 inches (in) was due to a
combination of factors including:

  • changing climate patterns (the primary driver at 9-17 cm or 3.5-6.7 inches);
  • an increase in the conveyance capacity (i.e., the measure of water flow capacity of a channel) of the St. Clair River (7-14 cm or 2.8-5.5 in);
  • ongoing glacial isostatic adjustment (i.e., adjustment of the earth’s crust resulting from the removal of the weight of the glaciers) was 4-5 cm or 1.6-2.0 in.

So climate change is the key culprit. The main recommendation from the study is quoted below:

“The Commission recommends that the Governments undertake further investigation of structural options to restore water levels in Lake Michigan-Huron by 13 to 25 cm (about 5 to 10 in). The low end of the range addresses compensation for the early 1960s channelization and the higher end would offset the additional change in conveyance capacity that has been estimated by the Study Board to have occurred since then.”

For those interested in the complete study it can be found here:

If you’re interested in the work of the International Joint Commission, click here