A federally commissioned pilot study in the Great Lakes Water Basin has shown a large drop in groundwater levels that could threaten the quality of water south eastern Wisconsinites drink.

The pilot conducted by the United States Geological Survey found groundwater levels in the Milwaukee and Chicago metropolitan areas have lowered by as much as 1,000 feet.

Howard Reeves, USGS hydrologist and author of the pilot report, said the decline could cause a drop in water quality and an increase in cost for citizens who tap into groundwater sources in Milwaukee.

“[The drawdown] is significant because it can increase the cost of pumping in communities requiring wells,” Reeves said. “Water tends to move from high to low, so the drawdown could cause poor quality to move toward the wells.”

The largest drops in groundwater level occurred mostly in Milwaukee and Chicago, centers of expansive groundwater pumping, Reeves said.

He added the Great Lakes drainage basin has provided well water for southeastern Wisconsin since the 1900s and provides more than 34 million people with water. Milwaukee’s eastern neighborhoods would not be affected by poor water quality because citizens there get water directly from Lake Michigan.

However, the study also found that groundwater levels outside Milwaukee in the Great Lakes drainage basin have stabilized and even increased when local agents slowed down the rate of groundwater pumping.

“[Water levels] stabilized because local agencies moved away from continuing pumping through the aquifer system,” Reeves said. “It has actually stabilized and rebounded from its lowest decline.”

Researchers hoped the study would allow local agencies to make decisions for their own groundwater issues, Reeves said.

Although Madison is not within the Great Lakes basin, local USGS hydrologist Mike Fienen said water levels have dropped in the area as well, albeit not as much as in southeastern Wisconsin. He elaborated on an option a local program is studying that would prevent further water level and quality decreases.

“On campus, the Water Resources Management masters program is trying to replenish Madison area groundwater using treated waste water – treated by the Nine Springs Plant – then they discharge it into a creek,” Fienen said.

The USGS five-year pilot took place from 2005 through 2009 and cost the federal government nearly $5 million, Reeves said.

– –

In the Feb. 9 article “Great Lakes water level sinks by more than 1000 feet in last century,” it should have said “ground water level” instead of “level.” The United States Geological Survey was involved in the study rather than the United States Geographical Survey. It should also be clarified that the UW Water Resources Management is promoting a study to look at local water – they are not implementing a plan. We regret the errors.