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Groundwater study: still more questions than answers for researchers in Chippewa County

By LeAnn R. Ralph

BLOOMER — Going into the second year of a five-year study, groundwater researchers in Chippewa County still have more questions than answers.

The Chippewa County land conservation office hosted the second annual public informational meeting about the groundwater study at Bloomer Middle School March 18.

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

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 into 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 and is researching the impact of high capacity wells near the headwaters of streams, the increased use of high capacity wells, changes to the landscape from frac sand mining and the implications for groundwater recharge, and water use management and the sustainability of water use.

One of the researchers, Madeline Gotkowitz, a hydrologist with WGNHS, said the study is important because groundwater and surface water are connected.

One of the questions that the study seeks to answer is whether the use of high capacity wells will impact streams, lakes, ponds and rivers in this area, she said.

Monitoring wells have been set up for Como Creek, Trout Creek and the South Fork of Trout Creek, and stream gauges are being used to determine the natural variability of the flow, Gotkowitz noted.

Over the last five years, the state Department of Natural Resources has become much better at keeping track of  high capacity wells and how much water they pump, she said.

Groundwater recharge happens everywhere in the landscape, but some topography and soil types are better at allowing recharge than others. There are certain runoff management practices that can encourage infiltration for groundwater recharge, Gotkowitz said.

The study’s computer model will assess recharge rates before frac sand mining and will predict recharge rates 30 years from now after the mining is completed, she said.

Recharge rates

In this area, the average amount of rainfall is 31 inches per year, Gotkowitz said, with a minimum in a drought year of 17 inches and a maximum of 44.5 inches in a wet year.

In 1950, the area had seven inches of recharge. In 1951, the area had 12 inches of recharge. The average recharge is 8.5 inches, and could be as little as three inches in a dry year or 15 inches in a wet year, she said.

Generally speaking, about one-third of rainfall and snowmelt goes toward recharging the groundwater, Gotkowitz said.

The rate of recharge is not as important as how the rainfall and snowmelt feed into the surface waters and the wells, she said.

Over the next couple of years of the study, recharge rates will be put into the groundwater flow model to see how streams are being affected, Gotkowitz said.

Questions

Following a formal presentation by the Gotkowitz, Mike Parsen, also a hydrologist with WGNHS, and Mike Fienen, a hydrologist with USGS, audience members were allowed to ask questions.

• How long does it take the groundwater to flow from the top of a hill to a stream?

Gotkowitz said in this area, groundwater moves about six inches a day or 182 feet in a year. If it is 1,000 feet from a hill to a creek, it will take five years for the groundwater to reach the creek. If the creek is 3,000 feet away, it will take the groundwater 15 years to reach the creek.

• How many Chippewa County frac said minds have test wells?

Dan Masterpole, Chippewa County conservationist, said that all industrial sand mines in Chippewa County that have been permitted have test wells.

• How do high capacity irrigation wells report water use?

Parsen said the owners of all high capacity wells are required to submit annual reports to the DNR on the amount of water used on a month-by-month basis.

The high capacity well usage is self-reported, but the DNR has verified that the reports are quite accurate, Fienen said.

Several audience members were skeptical about the accuracy of self-reporting for high capacity well usage.

Mark Dietsche, chair of the Town of Grant north of Colfax and a participant in the study who has a high capacity well on his farm, said operators have no reason — that there is no advantage — to lying about the amount of water used by a high capacity well.

• Should there be more concern about groundwater recharge rates as the frac sand mines are operating or 30 years from now when they have been reclaimed?

One scenario that will be included in the computer model is the recharge rate when the mine is open, the soil has been stockpiled, and rain is falling directly on the Wonewoc sandstone being mined, Gotkowitz said.

• Is it useful to use averages in the groundwater study?

Groundwater has short-term variability and reacts slowly to rainfall or snowmelt, so it is appropriate to use averages, Fienen said.

The groundwater study will model three different situations: before mining, during mining, and after reclamation, he said.

• How many mines in Chippewa County have processing plants and use flocculants (a chemical to help the fines settle out of the sand)?

Three mines in Chippewa Count use flocculants, Masterpole said.

• Are chemicals used in mining being measured in the groundwater?

Testing for chemicals is not part of the groundwater study. The frac sand companies are testing voluntarily, Masterpole said.

• Is the number of high capacity wells going to make a difference to the area?

Yes, Gotkowitz said, the number of high capacity wells will make a difference.

It is important to have a model to help understand the groundwater. A model like this will be a tool to know the cumulative impacts of high capacity wells, Fienen said.

In the Central Sands region around the Portage area, the DNR is doing a pilot project to better understand how to look at the cumulative effects of high capacity wells, he said.

According to news reports, lakes in the Central Sands region have dried up, so that houses once located on a lake are now surrounding dry meadows where trees and grass are growing.

One question answered by the study will be how to manage the high capacity wells so that stream flows are not affected, Fienen said.

• Is the study looking at both the quantity of the groundwater and the quality of the groundwater?

The study is only looking at the quantity of groundwater, but quantity must be understood first before quality can be considered, Fienen said.

• Is there a proper procedure for abandoning high capacity wells?

If wells are not abandoned properly, they can provide a conduit for pollution to get into the groundwater, Gotkowitz said.

High capacity wells are generally filled with pea gravel, and then a 15 to 20 foot deep cement plug is poured into the top of the well, she said.

• Are precipitation differences caused by climate change going to be incorporated into the study?

There are many different ways to look at the future, and the groundwater model that will be developed during the study will look at rainfall in a dryer future and in a wetter future, Fienen said.

The model will be used for prediction, but it will help in the understanding of how groundwater works now, Gotkowitz said.

• Will Wisconsin ever be like Nebraska, where the Ogallala aquifer is going dry and there are water boards to govern the use of water?

Wisconsin receives an average of 31 inches of precipitation per year and has an unbelievable amount of groundwater storage, Gotkowitz said.

Still, “all pumping is local … it matters how many wells and how close they are and where they are,” she said.

It will not be an issue of running out of water for Wisconsin but an issue of how, where and when it is pumped, Gotkowitz said.

“Water is a finite resource that we need to sustainably manage and figure out how to use responsibly,” Parsen said.

Another public informational meeting about the third year of the Chippewa County groundwater study will be held next year.