If Lake Michigan looks like it has shrunk in the past year, it's not a mirage.
Water levels are eight inches below last July, and 20 inches below their long-term average for this month. The lake now hovers a little less than a foot above its record low for July, set in 1964.
Nature - precipitation, temperature, lack of winter ice cover - is a driving force behind lake levels, but humans have a played a significant role as well.
It long has been acknowledged that historic dredging and mining in the St. Clair River, the primary outflow for Lakes Michigan and Huron, permanently lowered the connected lakes by about 16 inches.
A recently completed $15 million study funded by the U.S. and Canadian governments found that unexpected erosion since a U.S. Army Corps of Engineers dredging project on the river in the early 1960s dropped the lakes' long-term average by as much as an additional five inches. But that study, co-led by an Army Corps employee, concluded that the erosion is not ongoing and is therefore not triggering further water loss.
The study authors initially decided there was no need to explore some type of physical fix on the St. Clair to slow the outflow from Michigan and Huron and restore the lost water, but they were overruled by the International Joint Commission, which funded the study and oversees U.S. and Canadian boundary waters issues.
The study authors subsequently evaluated a range of options and concluded a variety of structures could indeed be built to throttle flows on the St. Clair, but they determined that any such project could take decades to complete, cost up to nearly $200 million and inflict harm in some areas of the lakes as well as benefit others.
They also noted such a "fix" could cause trouble for endangered sturgeon in the St. Clair, as well as exacerbate erosion and other problems if high water returns in the coming years, which is a distinct possibility given the vagaries of long-term weather patterns, as are further declines.
The ultimate conclusion of the study submitted to the Joint Commission this spring is that learning to live with ever-fluctuating lake levels is the best way to deal with the problem. But the Joint Commission has not decided whether to accept that recommendation, and on Thursday about 60 people turned out for a public hearing in Milwaukee to weigh in on the issue. Most who spoke didn't buy the study board's recommendation to essentially do nothing.
More at the link
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JanforGore
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