Chippewa County groundwater study enters third year

By LeAnn R. Ralph

BLOOMER — As the five-year Chippewa County groundwater study enters its third year, researchers are gaining momentum on the data they are collecting.

The Chippewa County Land Conservation and Forestry Management Department hosted the third annual public informational meeting about the groundwater study at Bloomer Middle School March 17.

The groundwater study is being conducted by Chippewa County, the Wisconsin Geological and Natural History Survey and the United States Geological Survey and is studying the impacts of high capacity wells operated by municipalities, farms, and frac sand mines.

Of particular concern is the impact that the proliferation of frac sand mines will have on on groundwater and on surface waters, such as trout streams, because of additional high capacity wells used for washing the sand and because of changes to the landscape that could significantly affect groundwater recharge rates.

The study area covers the western side of Chippewa County where many of the frac sand mines are located and extends east of Bloomer, north in Barron County and east into western Dunn County almost to Colfax and includes the Red Cedar River.

The study began in the fall of 2012.

Stakeholders and contributors of data to the study include all of the frac sand mining companies: Chippewa Sand Company; EOG Resources; Preferred Sands; Superior Silica Sands; Taylor Creek Transit; West Wisconsin Sand Company; Great Northern Sand; and Hi-Crush Augusta LLC.

Other stakeholders include local farmers and other citizens; Trout Unlimited; the Wisconsin Department of Natural Resources; and the Wisconsin Farmer Union.

The scope of the study is to develop a soil-water-balance model and a groundwater flow model to evaluate changes to the groundwater based on water usage and recharge rates.

The project is designed to provide a model that can be used in West Central Wisconsin to help make decisions on activities that impact the groundwater.

1950 to 2010

The recharge model that researchers are working on is using groundwater data collected from 1950 to 2010.

Average rainfall in that time period is 31 inches per year, with a minimum of 17 inches and a maximum of 45 inches.

The groundwater recharge rate in the time period is an average of 8.2 inches, a minimum of 2.5 inches and a maximum of 14 inches.

Every year, about one-third of the precipitation that falls as rain or snow reaches the groundwater.

Stormwater

One person in the audience asked if the researchers expected the stormwater runoff to increase or decrease from the sand mines.

Without adequate stormwater controls, the runoff will increase, said Madeline Gotkowitz of the WGNHS.

Within 15 or 20 or 25 years after the sand mines have been reclaimed, the runoff will not be excessive, she said.

The researchers presented information about infiltration rates (the rate that rainwater soaks into the ground) indicating that forests and prairies or grasslands have the highest infiltration rates and that agricultural row crops and reclaimed mine sites have the lowest infiltration rates.

Thirty years after reclamation, data from other sand mine sites in Wisconsin indicate that infiltration is higher, although only a few years after reclamation, the infiltration rates are poor, Gotkowitz said.

“Do you think sand mining will result in a permanent reduction of the groundwater?” asked one person.

“That’s what we are trying to get at with the study,” Gotkowitz said.

Another person asked about stormwater controls for the sand mines.

Chippewa County land conservation and the state Department of Natural Resources are working with the mining companies now to improve their stormwater control, said Seth Ebel of Chippewa County land conservation.

Several of the sand mines already capture all of the stormwater and use it in the processing of the sand, he said.

Recharge rate

Another person asked how fast water comes back into the groundwater.

Water will move through the sandstone at a higher velocity where the sand stone is more permeable, Gotkowitz said, noting that a molecule of water will move .8 feet per day.

At that rate, water would move 292 feet per year, or 1,000 feet in three years.

Trout streams

One person wondered about the impact of high capacity wells on streams.

High capacity wells, if they are close to a stream, can significantly reduce the stream flow, and there is a concern for trout habitat and streams in the sand mine areas, Gotkowitz said.

The groundwater model produced by the study will indicate what to expect from sand mining and irrigated agriculture, said Dan Masterpole, Chippewa County conservationist.

The study will help identify what can be done to mitigate the effects on the groundwater, he said.

“We’ll be looking at how to minimize the impacts,” Masterpole said.

Several people wondered if the DNR has expressed interest in the results of the groundwater study.

Yes, the DNR is interested in using the information to help with writing permits for  high capacity wells, said the researchers.

The Lake Beulah case said the DNR must exercise its authority to look at the impacts of high capacity wells, Gotkowitz said.

The Lake Beulah case involved a state Supreme Court ruling which said the DNR must consider the potential harm to public waters when a permit application for a high capacity well is reviewed.

The groundwater study is being conducted by public agencies, so the information is in the public domain and will be available to the DNR and to engineering consultants, Gotkowitz said.

More facts

Here are some of the other facts that were presented at the public informational meeting.

• In the study area, frac sand mines have high capacity wells that are 250 to 400 feet deep. Municipal wells are 150 to 300 feet deep. High capacity irrigation wells are 50 to 300 feet deep.

• In 2013, five industrial sand mines pumped 105 million gallons of water; 22 irrigated agriculture wells pumped 689 million gallons of water; five municipal wells pumped 98 million gallons of water; and other uses accounted for 6 million gallons of water. (To put the gallons into perspective, the Village of Colfax pumps about 30 million gallons of water per year.)

• Layers of sandstone in this area are the Tunnel City, the Wonewoc, the Eau Claire, and the Mount Simon. The water table is on top of the Eau Claire formation. The Wonewoc formation is mined for frac sand.