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Lake Superior Level is Up 10 Inches

Posted on: Tuesday, 6 May 2008, 06:00 CDT

The level of Lake Superior rose 6 inches in April, double the usual increase for the month, and is closest to its monthly average than any time since July 2006.

The big lake is now 8 inches below normal but is a whopping 10 inches above the level at May 1 last year. Over the past two years the lake had been as much as 22 inches below long-term monthly averages.

That extra 10 inches should make it easier to launch and dock boats at marinas across the lake compared to last spring. And there's more water covering more waterfront beaches and wetlands left high and dry last spring and summer.

The International Lake Superior Board of Control reports that rain and snowfall over the Lake Superior basin were well above normal in April, continuing a general upswing in water levels that started last fall.

April was unusually wet across the western portion of Lake Superior after three straight dry months. At the Brule River State Forest in Wisconsin, for example, 24 inches of snow fell in April -- more than the 22 inches that fell in January, February and March combined. Duluth received 3.8 inches of liquid equivalent precipitation in April, much of it snow, which was 1.7 inches more than normal.

Lake Superior is expected to continue to rise each month into autumn, when it begins a cyclical downturn through April, said Carl Woodruff, hydraulic engineer for the U.S. Army Corps of Engineers' Detroit District.

It's unclear whether the current increase is part of a long-term trend back toward normal water levels or a hitch before low water levels of the past few years continue.

Experts believe that unusually dry weather and increased evaporation from more ice-free months have contributed to Lake Superior's recent dip. But some people believe at least some of the Great Lakes may have more problems than just climate variations. A $15 million study by the International Joint Commission is examining whether human actions are needed to help stabilize water levels in lakes Superior, Michigan and Huron. Problems could include increased outflow because of past dredging.

Though Superior isn't affected by lower levels on Huron and Michigan, dams on the St. Marys River can be regulated to allow more or less water to leave Lake Superior to feed the lower lakes, which can tie the big lake to problems of the other lakes.

While Superior appears to be recovering, Huron and Michigan still might have issues. The monthly report noted that lakes Huron and Michigan rose 8 inches in April, when they usually rise 11 inches. Those lakes now sit 2 inches lower than May 1, 2007, and are 18 inches below their long-term average.

Source: Duluth News-Tribune (Duluth, Minn.)

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