The town hall in rural Emerald Township in eastern St. Croix County, Wis. happens to be within sight of one of the biggest industrial livestock facilities in western Wisconsin. A half-mile down the two-lane road, Emerald Sky Dairy’s two huge barns are home to about 1,500 cows that produce 14,000 gallons of milk per day — and a lot of manure.

All the manure is used on nearby agriculture fields as fertilizer. The soil and plants can only absorb so much nitrate, though, and such spreading can lead to pollution of both surface water, like lakes and streams, and groundwater, the aquifers that most of Emerald Sky’s neighbors depend on for drinking.

Now, the Town of Emerald has learned that the amount of nitrate, a chemical often connected to large-scale manure spreading, in its well water is more than four times higher than what is considered safe. It has increased five-fold since the well was dug in 2007.

The test results show both an extreme case of contamination, and reflects a growing problem across the county, and throughout Wisconsin.

“The Emerald Town Hall well has some of the highest groundwater nitrate that have been observed through the County’s [Citizen Groundwater Monitoring Program],” said Cole Webster, Water Resource and Outreach Specialist for St. Croix County.

Both the Centers for Disease Control and the state of Wisconsin say no one should drink water with more than 10 mg per liter of nitrate.

About 11 percent of wells tested through St. Croix County’s Citizen Groundwater Monitoring Program exceed that level. Only a few exceed 30 mg per liter. Emerald Town Hall was at 40.3 mg per liter last November. The town installed a filtration system in 2019 to remove the pollution, at a cost of approximately $2,500.

Webster stresses that there’s no way to directly link the town hall’s nitrate problem and any particular source. Many farmers have spread manure on fields for many decades, other sources exist, and the area’s aquifer is notoriously complex.

Much of St. Croix County’s bedrock is called dolomite, which differs from the typical sandstone in the region. Dolomite contains high amounts of calcium carbonate, which slowly dissolves as rainwater flows through it. This creates cracks, caverns, sinkholes, and other geologic features that make it easy for water to flow through the bedrock.

This “karst” geology means it can be pretty easy to pump water for a well — and that surface contamination can quickly make it to the aquifer.

“The groundwater system throughout much of the county, including Emerald, is especially complex due to the presence of the Prairie du Chien dolomite aquifer,” Webster says.

While the rock has been there for millions of years and modern agriculture has occurred for several decades — the nitrate level clearly seems to have skyrocketed only in the past 10 years.

Proactive protection

St. Croix County has undertaken significant efforts in recent years to monitor and protect its groundwater. The water is the sole source of drinking water for residents and businesses, and susceptible to pollution. It is a critical resource, and a growing concern.

Nitrate is one of the biggest concerns for drinking water across the county. It can cause “blue baby syndrome,” which lowers oxygen levels in infants, leading to comas or even death if not treated. It is also believed to cause other pregnancy complications, cancer, thyroid conditions, and high blood pressure.

While public wells, like those used by cities to provide water for their residents, are required by law to meet safety levels, the many private wells in the county are up to the individual owner to monitor and treat. About half of the county’s residents get their water from a private well, Webster says.

St. Croix County recommends that private well owners test their water annually for nitrate and bacteria. The county offers several free water testing clinics each year, which lets private well owners have their water tested for nitrates for free.

The county also launched a monitoring program in 2019, using volunteers with private wells. About 180 well owners across the county receive free water testing, in exchange for sharing the levels with the county. It allows staff to see where nitrate might be a problem, and observe any changes over time. Nitrate levels in much of the county’s groundwater appears to have stayed steady in recent decades, or improved — but not in Emerald.

Early detection of nitrate in groundwater is important so contamination can be stopped while there is still time.

“Once contaminants enter the groundwater system, removal is typically not possible, or it is extremely costly,” Webster says. “Therefore, it is important to reduce the amount of contamination entering the system.”

He adds that the county’s research has indicated that the more agriculture surrounding a well, the greater the chance of nitrate contamination, which comes from fertilizers and manure.

More manure, more problems

Emerald Sky Dairy was purchased and expanded by Tuls Dairies, a Nebraska company, in 2016. It has caused a series of problems with pollution in the past five years.

The challenge of confined area feeding operations (CAFOs) is straightforward: Manure is always increasing. The facilities have a set amount of storage, and it must be routinely spread on surrounding fields.

It can provide excellent fertilizer for crops, but the plants are only able to use a certain amount, and the effects of soil, geology, and precipitation can still push much of it down out of reach.

“Even when applying just the right amount, nitrate often leaches to groundwater under wet conditions when water carries nitrate past the root zone of plants quicker than the plants are able to take it up,” specialists with the University of Wisconsin Extension wrote in a 2006 report for St. Croix County.

In 2017, the company was reported to the DNR for spreading solid manure on fields in February, when the ground was frozen.

The following winter, tens of thousands of gallons of manure from its storage pits leaked into a neighboring wetland. The company did not report the spill, and it was not discovered by authorities for several months.

In November 2019, after Emerald Sky workers spread manure on a nearby farm field, the waste ran off the damp, possibly frozen ground and flowed into nearby Hutton Creek, a trout stream. There, it killed fish and otherwise wreaked ecological havoc.

The company is currently working on a proposal to increase its operation to at least 6,000 animals. The application has been on hold for several months.

Wisconsin nitrate rule

Emerald and St. Croix County are part of a broader story in Wisconsin about nitrate and groundwater. The substance has been increasing in many aquifers around the state in recent years, with environmental, health, and financial costs. The nonprofit Environmental Working group reports that 1.2 million Wisconsin residents drink water with elevated levels of nitrates. Removing it from drinking water has already cost hundreds of millions of dollars.

The state’s Department of Natural Resources is working on new rules to prevent nitrogen spread on crop fields from reaching groundwater. It focuses on identifying areas throughout the state where groundwater contamination is a concern, and creating regulations for manure management.

A public comment period on the proposed rule was held in March, but the DNR may not ever get to implement it. The Environmental Working Group reported earlier this month that some legislators may use a special authority to block the rules.

“Unless Wisconsinites step up and demand action to clean up nitrate in our drinking water, powerful supporters of industrial agribusiness in the legislature can and will do what they can to stop this rule from going forward,” said Jamie Konopacky, director of EWG’s Midwest office.

The proposal would set goals for rules include establishing standards for how much manure or fertilizer can be spread on certain fields; prohibitions on spreading after September 1, when the growing season is ending and few plants are absorbing nitrogen; and otherwise using formulas to determine how much nitrogen certain crops can use, and how much nitrogen might leach into groundwater based on local conditions.

Implementation of the rules could be a factor in future proposals in the St. Croix River watershed. A recent application to house 26,000 hogs in Burnett County would also produce large amounts of manure to be spread in areas with shallow aquifers and numerous streams.

Water is restless, and whether it’s on the surface or underground, it’s almost always moving.

Most of the groundwater in St. Croix County flows west, toward the St. Croix River. It seeps out of springs in the bluffs and in the river. It provides the pure water that keep the St. Croix clean and healthy. It’s as much a part of the river as fish and turtles. Contamination of these aquifers could not only poison nearby wells, but ultimately hurt the river.

Upcoming St. Croix County Water Testing:

• July 27th – Kinnickinnic Town Hall – River Falls, WI (PDF)
• August 24th – St. Croix County Services Center – New Richmond, WI (PDF)

More information:

The Hudson Star-Observer recently published three articles related to this issue by Steve Gardiner:

• As animal feedlots grow, so do fears
• Keeping water quality high is concern for many
• Karst provides problematic passages straight to groundwater

Note:

St. Croix 360 received the Emerald Town Hall water test results from local residents, who received them from the town via an Open Records Request; St. Croix 360’s request to the town for official copies has not been answered at time of publication.