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Great Lakes Article:

Mild winter exposes Lake Michigan to risk of low levels

In normal winter, ice cover slows evaporation, snow tops off water

By MEG JONES

Milwaukee Journal Sentinel

Last Updated: Jan. 10, 2002

As sand bars grow, docks get higher and Lake Michigan continues to shrink, a much-needed water boost that normally happens each winter isn't materializing.

So far, there's not much snow to melt in the spring and run into the Great Lakes. In addition, higher than normal temperatures mean little or no ice forming across lakes to prevent evaporation, experts said.

Relatively benign weather since the last El Nino of 1997-'98 has dropped water levels in the Great Lakes to some of the lowest in decades. Last year, Lake Michigan was the lowest in 35 years, authorities said.

Thanks to this winter's unseasonably balmy weather, Lake Michigan's water is now evaporating faster than normal.

Usually by this time of year, 60% to 70% of Lake Michigan is covered in ice, but "this winter there's hardly any ice cover on Lake Michigan at all," said Roger Gauthier, a U.S. Army Corps of Engineers hydrologist based in Detroit.

"That's not a good sign. That's a sign that lake levels will be under pressure again," Gauthier said.

Lakes always evaporate in the winter as cold wind blows over warmer water. As ice forms the evaporation slows. But not this year.

In Lakes Michigan and Huron, which are the same height because they're connected by the Straits of Mackinac, the water level has dropped by more than 40 inches since 1997 and remains 13 inches below average. Lake Superior is 3 inches below average, and Lake Erie is 4 inches below normal, while Lake Ontario is at its average level.

With lower water levels, shipping companies can't fill their ore carriers as full for fear of running aground.

Ships traversing Lakes Superior and Michigan are hauling an average of 64,000 tons, down from 70,000 tons in the mid-'90s before the Great Lakes began dissipating. Last year was worse, with ships forced to load only 60,000 tons of coal, iron ore, cement and other commodities, said Glen Nekvasil, vice president of corporate communications for the Lake Carriers

Association.

"When we leave 10,000 tons of iron ore or coal on the dock, we leave behind $350,000 worth of cargo," Nekvasil said.

"What it really means (is) when we're leaving cargo behind, a ship has to make more trips to deliver the same amount of cargo."

Larry Sullivan, chief engineer for the Port of Milwaukee, noticed ships coming in lighter than usual last year. Dredging was done at the Milwaukee port in 2001, but the project had been planned for a long time and wasn't related to low water levels, Sullivan said.

As the Great Lakes drop, docks get higher, sandbars get bigger and some boat ramps become inaccessible. When water levels are lower, waves act differently, which can be hazardous to boaters.

"Every spring when we get storms, we get breaking wave conditions where we aren't used to seeing them," said Philip Keillor, coastal engineering specialist with the Sea Grant Institute in Madison.

"Last spring a fishing tug almost got rolled over going into Two Rivers. That's a problem for shallower harbors like Two Rivers but also deep harbors like Superior, where in late November they had a storm with waves 20 feet high," Keillor said.

Keillor said receding water is also rapidly aging harbors that were built a century ago. The wooden structures are exposed to the air in many spots, which means they're rotting faster, Keillor said.

A shallower Lake Michigan isn't all bad, though. There are more beaches. Shores aren't eroding, and some of the areas formerly under water are now wetlands, which offer plenty of food and habitat for a variety of wildlife species.

"We definitely have more biodiversity on our shores since 1997," Gauthier said.

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