Even back in 2003, several years of near-record low water levels had left this dock on East Grand Traverse Bay near Traverse City, Mich., surrounded by beach grass. Water levels are even lower now. (AP Photo/Traverse City Record-Eagle, John L. Russell)
Last month, water levels in Lake Michigan and Lake Huron dropped two inches below their lowest recorded monthly average since the U.S. Corps of Army Engineers began keeping records in the 1860s.
One cause that's overlooked - which also affects rivers and lakes throughout the Midwest - is a sharp increase in the number of wells that are being dug, says Robert Glennon, regents' professor and Morris K. Udall professor of law and public policy at the University of Arizona.
"There has been an explosion of ground water wells throughout the state [of Illinois]," says Glennon, author of the 2009 book Unquenchable: America's Water Crisis and What To Do About It. "You've got record high corn prices, terrible drought and high cost of farmland. All of those things have been leading toward drilling of new wells."
it's not just going on in Illinois. Many new wells are being dug in every Midwestern state, partly because the laws are "ridiculously permissive," he says.
The wells don't take water directly out of lakes and rivers. But groundwater flows are an important source of water for them. Groundwater is why a river flows along full of water even when it hasn't been raining.
"If you put in a well that is located a quarter of a mile from the river, it is going to hammer the river," Glennon says. "If it uses 500 gallons of water per minute and there are 10,000 of these wells, you have a problem in your rivers."
As the water is pumped away, water tables drop, creeks, wetlands and lakes lose their water and riparian vegetation declines along with the wildlife that depends on it.
Much of the water from those new wells is going to irrigation.
"No one used to irrigate except in the West," Glennon says. "[And] Irrigation is the most intently consumptive use of water in the United States."
Drought conditions, which encourage drilling of wells, are continuing in the Midwest.
While wells are a factor in lower Lake Michigan levels, the loss of ice cover has a bigger impact, Glennon says. Surprisingly, because air is drier in winter, evaporation is greater in cold months than in summer. Ice cover can slow evaporation, but Glennon cites a 2012 study published in the Journal of Climate that reported ice cover has over the last 40 years declined on the Great Lakes by an average of 71 percent.
Read "Lower Great Lakes levels have economic cost" here.
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