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Published June 04, 2009, 12:00 AM

Twin Ports meeting on Upper Great Lakes water levels study

Experts on Great Lakes water levels will hold a video conference June 11 in several cities, including Superior, to offer their take on a new study of the St. Clair River.

By: John Myers, Duluth News Tribune

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Experts on Great Lakes water levels will hold a video conference June 11 in several cities, including Superior, to offer their take on a new study of the St. Clair River.

The study, ordered by the International Joint Commission and released last month, looked at the impact that dredging the St. Clair River had on water levels upstream.

The river, which connects the Lake Michigan-Huron system with Lake Erie, was dredged decades ago, and critics said that dredging and subsequent currents scoured the river channel and allowed more water to leave lakes Michigan and Huron faster than before.

Critics of the past dredging, especially property owners on Lake Huron, blamed the riverbed scouring for unusually low water levels in recent years, though skeptics note the same lakes saw record high levels in the 1980s, well after the initial dredging occurred in 1962.

More than 100 scientists looked at the issue and concluded that:

  • Lakes Michigan and Huron, on average, dropped 9 inches between 1962 and 2006 (although the lake is up considerably since 2006).

  • That decline was due mostly to climate change — including drought and increased evaporation — as well as changes in the Earth’s crust that raise lake beds and change elevations.

  • Some of the drop was due to increased movement of water through the St. Clair River, but much of that increased flow might have been caused by a single event in the mid-1980s, such as an ice jam letting loose.

  • The St. Clair riverbed has not been eroding, or scouring, since 2000.

    The report concluded that no action to change the bed of the St. Clair River is necessary at this time. But critics immediately panned the report, saying it failed to include key factors.

    The issues of the St. Clair River can’t physically affect Lake Superior. Because Lake Superior is at a higher elevation and flows at a natural rate into the St. Marys River, lakes Huron and Lake Michigan could be drained entirely without affecting Superior’s level.

    But because the International Lake Superior Board of Control can let more water out of Lake Superior through dam operations, the St. Clair River issue can indirectly affect Lake Superior if the governments of Canada and the U.S. agree Lake Superior water should be used to refill lakes Michigan and Huron faster.

    “There is a regulation plan that allows increasing or decreasing the amount of water leaving Lake Superior to affect the [lower] lakes. So what happens downstream can affect Lake Superior,” said Jill Wingfield, spokeswoman for the International Upper Great Lakes Study group. “The second phase of the study will be to look at what role Lake Superior plays in the [system]. So this should interest people around Lake Superior.”

    The St. Clair River issue became heated in 2007 when lakes Michigan and Huron dropped to near record-low levels, leaving some docks, boat landings and marinas high and dry.

    But the two lakes have risen more than a foot over the past year and are now just 5 inches from the long-term average depth.

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