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Satellite Image of the Great Lakes basin. (U.S. Army Corps of Engineers, Detroit District.)
Satellite Image of the Great Lakes basin. (U.S. Army Corps of Engineers, Detroit District.)


Raise the Great Lakes? If only it were so simple Add to ...

Last summer, at 13 hearings in communities from Ohio to Thunder Bay, the International Joint Commission (IJC) heard from more than 3,000 people concerned about Great Lakes water levels. Despite a record 14 years of low levels, some recalled previous highs and counselled caution and acceptance of current conditions. However, most who spoke – especially cottagers on Georgian Bay – wanted action to restore higher levels.

Having grown up in Ludington, Mich., on the shores of Lake Michigan and worked in a family resort, I know that vacation homes – passed from generation to generation – are frequently more important than “year-round” houses. So, throughout the hearings, I was challenged by conflicting realities. Cottagers and businesses were obviously being seriously hurt by low water. But I knew that their single focus on outflows from Lake Huron down the St. Clair River omitted other critical causes. I knew the IJC could not deliver them from their misery, even if we delivered unequivocal advice to the two federal governments to engineer something to slow the flow and raise the lakes.

One man, seeing my dismay, excoriated me for “hostile body language” and the audience applauded. Responding to my explanation that the IJC was authorized only to advise the governments and could not appropriate money or order new structures to be built in the St. Clair River, another man yelled, “Yes, you can!”, as if his loud voice could invest the commission with powers that rest only with the governments of Canada and the United States.

Unfortunately, it’s not so simple. While St. Clair River dredging projects between the late 1800s and 1962 (and probably some further erosion subsequently) did contribute to lower water levels in Lake Michigan and Lake Huron, the decline caused by channel alterations only exacerbates the key driver of water level changes: climate. Scientists tell us that low levels are caused by persistent decline in precipitation, lack of ice and the resulting increase in evaporation. In fact, evaporation is by far the top cause of water loss from the lakes. Scientists’ satellite images and anglers’ unused-ice fishing tip-ups can tell you that the amount and duration of wintertime ice has fallen dramatically since the 1970s.

In addition, the movement of the Earth’s crust in response to the melting of glaciers, a phenomenon known as glacial isostatic adjustment, has also contributed to the apparent drop in water levels, especially around Georgian Bay. Just in the course of my lifetime, GIA has caused an apparent drop of 18 centimetres.

Those who point only to the dredging of the St. Clair River are oversimplifying the dynamics. We can no more blame dredging for low water than we can say that children fail to learn to read because they lack glasses or healthy breakfasts. No doubt, some of them need glasses and better breakfasts, but many other factors are involved.

Blaming a previous government decision to dredge the St. Clair is certainly easier to accept than something as confounding as GIA. And there is nothing fraught with more controversy than climate change, which scientists link to water-level extremes. I would be much happier if good science showed that most of the recent low water conditions were caused by dredging in the St. Clair River. And it would be great if the only thing that blocked restoration of higher levels were a lack of political will.

But it’s not so simple. Any structure in the St. Clair River would have to account for the environmental effects on wildlife habitat, the consequences of further lowering water levels important to millions of downstream residents on Lake St. Clair and Lake Erie, the capacity to modify the controls in case of future high waters, and, most importantly, the unlikely capacity of any structure to make a real difference in Georgian Bay.

I support the principal findings of the IJC’s Advice to Governments, especially that we invest in understanding how to best manage and live with extreme water levels with adaptive management. And I wouldn’t object if the governments studied the costs, consequences and engineering challenges associated with installing adjustable structures in the St. Clair River. But I don’t want to contribute to the false belief that today’s extreme low levels can be largely explained by 50- to 150-year-old dredging projects. The science points to complexities with a lot of flashing yellow lights warning us to go slow in considering the best way forward.

Lana Pollack is U.S. chair of the International Joint Commission of Canada and the United States.

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