What is happening to Great LakesWater Levels?

What is happening to Great LakesWater Levels?

By Mary Muter, Georgian Baykeeper for Georgian Bay Association Foundation

Should we care about Great Lakes water levels? They seem like such huge lakes and in fact they do contain about 20 percent of the world’s fresh surface water. But only one percent is renewed each year through precipitation, keeping the system in balance. The rest is a glacial deposit left when the last ice age retreated. When water levels remain low,wetlands dry up and are converted to grass meadows. So, yes, we should care when water levels decline and remain low for now eight years as they have for Lakes Michigan and Huron and Georgian Bay.

Last summer the water levels of all the Great Lakes declined, and Lake Superior set record lows. With increased precipitation, Lakes Superior, Erie and Ontario recovered, but Lakes Michigan and Huron and Georgian Bay continued to decline.They are now about 10 inches below where they were at this time last year, and about 20 inches below the long-term mean. They are well below what the International Joint Commission (IJC) identified as “crisis conditions” in their extensive 1993 Levels Reference Study.

The Levels Reference Study was done at the request of the Canadian and US federal governments. Its purpose was to propose and evaluatemeasures that governments could take, under crisis conditions, to alleviate problems created by high and low lake levels.* The Study recommended interim measures that could be taken during these crisis conditions, such as reducing the flow in the St. Clair and Detroit Rivers. These measures would help restore the water level of Lake Michigan and Huron.

In the years since the Study was published, the Georgian Bay Association Foundation determined that ongoing erosion, shoreline alteration and historical dredging of the St. Clair River has resulted in an increase in the outflow of Lake Huron, thus contributing to the current low water levels on Lakes Michigan, Huron, and Georgian Bay (see the Baird Report posted under water levels atwww.georgianbay.ca).

So here we are in 2008, poring over a fifteen-year old document that nailed the problem on the head, a $20 million report (1993 dollars) that spelled out in great detail what the fix should be in the St. Clair River – because the lakes are currently in crisis, we should put in the St. Clair River interim measures identified in the 1993 Levels Reference Study. By taking action now, we can ensure that the water that has been here for thousands of years will be here for generations to come. It will also help restore wetlands that are essential for spawning and nursery habitat for fish. This should be done before we lose any more precious water.

Contact:Mary Muter
Vice President, Environment
Georgian Bay Association
Georgian Baykeeper for GBA Foundation

*Levels Reference Study Annex 6 Crisis Conditions Responses, 1993



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