Report: Dredging Water Causes Huge Great Lakes Water Loss
TRAVERSE CITY, Mich. (AP) -- Erosion caused by dredging and other human activities on the St. Clair River is causing Lakes Huron and Michigan to lose 2.5 billion gallons of water daily, says a private Canadian study released Tuesday.
Like a bathtub drain, the artificially deepened river is funneling vast amounts of water into Lake Erie, where it flows east to Lake Ontario and the St. Lawrence River before eventually being lost to the Atlantic Ocean, the study says.
Sponsored by the Georgian Bay Association, the report acknowledges that drought, evaporation and other factors have contributed to a steep dropoff in water levels on the three upper Great Lakes -- Huron, Michigan and Superior -- since the late 1990s. Huron and Michigan, considered hydrologically the same lake, are 21 inches below normal and Superior could hit a record low this fall.
"But the erosion in the St. Clair River stands out among these problems as a man-made issue that can be corrected fairly easily and within a relatively short timetable," the report says.
It suggests covering the eroding areas with rock and installing gates to regulate water flow southward from Lake Huron.
U.S. officials said they were conducting a five-year study that would recommend what to do. The Canadian group and environmentalists in both nations said waiting that long would severely damage wetlands, fish habitat, water quality and Great Lakes cargo shipping.
The Georgian Bay Association, which represents about 17,000 people living on the Lake Huron bay, commissioned a 2005 report on the St. Clair erosion by W.F. Baird & Associates, a coastal engineering firm.
It said dredging, mostly during the 1960s, and other commercial projects on the river's northern end had caused an 845-million-gallon outflow daily from Lake Huron.
But findings since then show the volume being lost is three times as much -- even topping the 2.1 billion gallons pulled from Lake Michigan each day to supply Chicago's municipal system, said Bill Bialkowski, an engineer who conducted the research.
"We're seeing drastic, sustained decline in the Michigan-Huron system at the same time that Lake Erie is rising," Bialkowski said.
The International Joint Commission, a U.S.-Canadian panel that advises both nations on Great Lakes policy, in February began a five-year study of water levels in the upper lakes. The effects of dredging, gravel mining, shoreline alteration and other activities in the St. Clair River will be among the matters examined, spokesman Frank Bevacqua said.
The commission has long known that dredging in the St. Clair -- and in the Detroit River farther downstream -- was affecting water levels in Huron-Michigan, Bevacqua said. But it's unclear how big a difference they have made, he said.
"It can't be all pinned on dredging at this point," said Scott Thieme, Great Lakes hydrology chief with the U.S. Army Corps of Engineers office in Detroit. "There hasn't been enough detailed study to say."
Great Lakes levels have fluctuated on roughly 30-year cycles at least since the mid-1800s. Thieme said another possible influence is "glacial rebound," a gradual rise of land masses depressed by glaciers during the Ice Age.
Bialkowski, however, said massive water losses he had documented were "indicative of water loss independent of naturally occurring fluctuations or those due to global warming. Research is showing us that this is a persistent, unpredecented water loss."
The Lake Huron-Michigan water level plummeted 3 feet between 1999 and 2001. Hot, dry weather -- which reduced winter ice cover and boosted evaporation -- and erosion on the St. Clair River are probably both to blame, said Roger Gauthier, a hydrologist with the Great Lakes Commission.
"You've had climate change plus a change in the outlet, a double whammy," he said.
(Copyright 2007 by The Associated Press. All Rights Reserved.)