DNR: Drought dramatically increased groundwater pumping in 2012
The drought of 2012 spurred a massive increase in groundwater pumping, with agriculture surpassing municipalities as the biggest user of water from underground sources, the state Department of Natural Resources reported Tuesday.
It was the first time in five years that the farm sector's use of groundwater exceeded municipal demand, the DNR said. The agency began keeping such records about five years ago.
The report looks at the use of both groundwater and surface water.
But the findings for groundwater are especially noteworthy as worries have grown over increased pumping and its effect on streams, lakes and neighboring groundwater supplies.
"The numbers are dramatic," said Bob Smail, water supply specialist with the DNR.
Groundwater pumping from agriculture irrigation jumped 83% to 135.2 billion gallons, the DNR said in its annual report on water withdrawals. The figures come from the state's largest users that need a permit to drill for water.
Farming's use in 2012 was equivalent to covering Dane County in 5 inches of water, according to a DNR analysis.
By comparison, municipal water use for the same period rose by 2.6%.
Until 2012, municipalities represented the largest single category of users that drew water from underground. That changed with the drought, with the farmers under pressure to pump more water for their crops.
In 2012, farm irrigation represented 46% of the water pumped. Municipalities totaled 34% last year. In 2011, municipalities took 42% and agricultural irrigation represented 35%.
The Central Sands region - typically the heaviest users of groundwater in the state - experienced a large increase. The region is one of the nation's largest producers of potatoes and has a substantial vegetable crop industry.
Portage County, the No. 1 groundwater user, experienced a 65% increase in water use in 2012, figures show. No. 2 Adams County had a 79% increase, and No. 3 Waushara County had a 68% increase.
By comparison, the next three largest counties have large urban and suburban populations and experienced a far lower growth in demand: Dane increased 11%, Rock increased 28% and Waukesha increased 6%.
George Kraft, a groundwater expert at the University of Wisconsin-Stevens Point, said "these pumping statistics show we are in a scary situation in Wisconsin."
He said groundwater pumping has harmed streams such as the Little Plover in Portage County and shrunk the size of lakes in central Wisconsin.
The Little Plover runs six miles from its headwaters before emptying into the Wisconsin River. Kraft said irrigation had forced some sections to run dry during the drought.
The Wisconsin Potato & Vegetable Growers Association says its members are responsible stewards of groundwater.
"2012 was an historic drought, not only in Wisconsin, but throughout the U.S.," said Tamas Houlihan, communications director for the group.
"Irrigation was and continues to be responsible for saving countless jobs, preserving Wisconsin farms and keeping food on our neighbors' tables at a fair and reasonable price.
"Water is only applied at the times and in the amounts that are required to produce Wisconsin's food."
Kraft said he is worried about the growing use of irrigation in other parts of the state, notably the northwest and the northeast, where large dairy farmers are expanding.
The number of irrigation wells approved by the DNR has averaged 122 a year between 2007 and 2012. Through Oct. 1, the DNR has approved 258 in 2013.
Kraft said the DNR's current authority to review applications for high-capacity wells is limited and doesn't taken into account the effects of many wells in one area.
Eric Ebersberger, a water regulator with the DNR, said the agency doesn't believe it has the authority to consider the effects of other wells.
"We acknowledge there are cumulative impacts," Ebersberger said. "We are challenged with respect to what our authority is."
But he said the agency is studying irrigation's effect and is collaborating with others, including universities and farm groups.
"We're looking into the problem and trying to find ways to resolve it," he said.