Spring 2008

Non-municipal wells can account for a large – and largely unreported – percentage of groundwater use in the state, according to a recently completed study funded by the Water Resources Institute.

UW Water Resources Research

Getting a Grasp on Groundwater

By Elizabeth Katt-Reinders

If water were money, Wisconsin would be rich. But even water-rich states need to manage their wealth.

According to Madeline Gotkowitz, that means not just focusing on water quality, but on water quantity as well.

“We don’t really know how much water we use,” said Gotkowitz, a hydrogeologist at the Wisconsin Geological and Natural History Survey who recently completed a research project that took a closer look at how—and how much—groundwater is used in two Wisconsin counties.

Until recently, only municipalities have been required to report their water usage. That means the state has not known how much water non-municipal wells have been pumping. But state legislation that went into effect last fall will allow the DNR to keep track of how much water is being pumped by non-municipal high-capacity well users such as farms, industries, and businesses. And research like Gotkowitz’s can help provide the details.

“The whole idea behind recording the pumping is to answer the questions: who’s using it? Where in Wisconsin are they using it? And how much are they using?” said Larry Lynch, a hydrogeologist at the Wisconsin DNR. “We’re also tracking for what purpose the water is being used,” he said.

Gotkowitz said that better records could help the state improve the way it monitors and manages groundwater.

In her study, Gotkowitz and her colleagues focused on Waukesha County, which is experiencing water shortages due in part to concentrated pumping in highly populated municipalities; and on Sauk County, which has no reported shortage. They compared the status and trends of groundwater use for these counties because they have very different patterns of population and land use.

“I wanted to contrast what happens in a suburban and urban county with one that is primarily rural,” said Gotkowitz.

Gotkowitz found that there was plenty of room to improve water use records in the two counties. She and her colleagues had to estimate about 75% of total pumping in Sauk County, and 40% in Waukesha County due to the absence of water use records by non-municipal sources.

“We don’t want to have to be estimating that….That’s too much. It would be a very small effort to get most of that reported,” she said.

Gotkowitz found that while highly residential Waukesha County pumps more water overall, their per capita use is much lower than Sauk County, which is primarily an agricultural county with few people.

In Waukesha County, 45% of total pumping is done for residential use followed by 39% for commercial and industrial uses. Due to the patterns of water use, most of the pumping is concentrated where the municipal wells are located and is causing long-term drops in groundwater levels.

In contrast, 45% of pumping in Sauk County is done for commercial and industrial users followed by 39% for agriculture and irrigation. This pattern of water use means that pumping is spread out across the county and has not had major effects on groundwater levels.

Gotkowitz said that getting a grasp on the status and trends in groundwater use can help Wisconsinites protect environmental resources and can inform future economic development. For example, locating even one high-capacity well too close to a trout stream could ruin the stream by drawing water that would have fed the stream. And when trying to locate a new water-intensive industry, planners and developers could compare water usage and the status of groundwater in different regions of the state.

At the most basic level, Gotkowitz said that how much water we’re pumping in Wisconsin is “just good to know. Clearly we’re going to want to be able to manage this resource.”

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