CRAWFORD AND VERNON COUNTIES - About 25 people gathered at the Franklin Town Hall on Monday, Dec. 10 to hear representatives of the UW-Stevens Point and UW-Extension Center for Watershed Science and Education. The discussion centered on results of the recent well water testing conducted in the watershed.
Dr. Paul McGinley, Director and Research Scientist, and Jessica Haucke, Research Specialist, addressed the group of assembled farmers and other interested citizens.
Generally, the results were described as “good,” with a few of the 44 samples testing high for coliform and nitrate. The testing program was paid for with funds from the group’s 2018 DATCP Producer-Led Watershed Grant. The group recently learned that they had been re-funded by DATCP for 2019 for the full $40,000, which will allow them to conduct another round of well water testing.
Once the second round of testing is completed, they will have sampled 25 percent of the wells in the watershed, giving them a good baseline understanding of groundwater quality.
“The Tainter Creek Watershed Council is a leader among producer-led watershed councils in pursuing this testing,” Haucke explained.
Groundwater
Dr. McGinley started the presentation with an explanation of what groundwater is, and where it comes from.
“Groundwater comes from rain, which percolates through the plant root layer of the soil and filters through rock until it penetrates deeply enough into bedrock that the water becomes continuous,” McGinley explained. “This layer in the bedrock where the cracks and crevices are completely filled with water is known as an aquifer.”
McGinley told the group that Wisconsin receives an average of 32 inches of rain per year. Of that, 22 inches is lost to evaporative transpiration, which can leave 10 inches to percolate in and become groundwater.
Ten inches of rain converting to groundwater each year on one square mile of ground is equal to about 23 million cubic feet of water per year. There are 31 million seconds in a year, which means that every second, almost three-quarters of a cubic foot of water is added to the aquifer – that’s about equal to a five gallon bucket.
“Essentially every farm is a water production factory,” McGinley explained. “And your groundwater originates near your well.”
McGinley explained that when rain falls from the sky, it is almost like distilled water. This means that all of the stuff that shows up in water is introduced once it starts to interact with the soil and the bedrock.
McGinley described how the type of bedrock influences the groundwater and leads to hard water with a neutral pH in the Tainter Creek Watershed. For this reason, he described the water as “very stable,” and thus not prone to being corrosive.
Coliform bacteria
Coliform bacteria was shown to be present in 25 percent of the wells tested. E.coli, which is a member of the coliform bacteria group, was not present in any of the samples that tested high for coliform. E.coli comes either from animal or human waste and is considered an indicator that the water could contain this kind of waste, and therefore pathogens.
“If there had been E.coli in any of the samples, we would have recommended stopping use immediately and re-testing,” Haucke explained.
“Detecting total coliform, is an indicator that there is cause for concern,” Haucke elaborated. “We encourage well owners who get a positive result for coliform to become sleuths to try and identify how the bacteria are getting into their water and what the source might be. An ongoing program of testing may be necessary to evaluate the success of any remediation efforts.”
Nitrate
McGinley described nitrate as the biggest cause for concern from the testing results. He was also quick to say, that the problem is widespread throughout the state.
Results in the 2.1 to 5.0 milligrams per liter (mg/L) range occurred in 11 percent of the samples; 39 percent were in the 5.1 to 10.0 mg/L range; and a concerning 23 percent were in the 10.1 to 20.0 mg/L range. Any result above 2 mg/L is considered to be above the naturally occurring level of nitrate.
Wells that test over 10 mg/L nitrate are not considered safe for women who are or may become pregnant and infants.
In response to a question about whether the test results showed clusters of nitrates, Dr. McGinley answered that there was a cluster of high nitrate concentrations in the northern part of the watershed. He emphasized that the best opportunity to capture nitrate before it reaches groundwater is in the plant root layer of the soil. This, he says, is one of the most compelling reasons to plant cover crops and maintain a continuous root structure in the soil throughout the year.
For residents whose wells tested high, Haucke listed the solution, and also short-term strategies.
“The solution is to eliminate the source of the nitrate,” Haucke said. “In the short term, residents with high nitrates in their well water can explore changing the depth of their well; they can carry or buy water; or they can install a treatment system such as reverse osmosis, distillation, or an anion exchange system.
In answer to a question about how often people with no nitrates showing up in their well water should retest, Haucke responded, “we recommend testing every year or two, and one test alone will not show a trend or demonstrate potential seasonal variations.”
Discussion
Farmer Brian McCulloh queried McGinley about whether there is any longitudinal data available for the area about groundwater quality.
“What our group wanted to do was to establish a baseline for groundwater quality in the watershed,” McCulloh said. “If we don’t have any historical data to compare it to, then we are really just getting started.”
McGinley answered McCulloh’s question by explaining that public water systems are highly regulated, required to test regularly, and would be the best source of any historical data. He said examples of public water systems in the area for which there might be results would be churches, taverns, and other public places like that. Private well owners are not required to test their wells, and not required to share their results if they do have them tested.
McCulloh pointed out that even decomposing plant material on the surface of the soil has potential to produce nitrate.
McGinley responded that decomposing plant material is always a source of nitrate on any land. When that occurs in the spring and fall, and if there are less roots in the soil, then it becomes more likely that the nitrate will make it into the groundwater.
Vernon County Conservationist Ben Wojahn added that the best way to prevent nitrate from getting into groundwater is to grow cover crops, and to use a Nutrient Management Plan to make sure that you are using the right amount of fertilizer on crops.
Bruce Ristow reported that the sample taken from the Bathtub Spring in Star Valley tested positive for coliform. He was quick to point out that it is just basically a tube protruding from a hillside that allows the water to run into an old bathtub. The well is not deep, and does not have a casing.
Forest Jahnke reported that Crawford Stewardship Project would be launching a program of groundwater testing in Crawford County in 2019.
“If you know of people that wanted to test, but were just outside your watershed boundary, send them our way,” Jahnke said. “We plan to add to the results obtained by your group with our own testing program paid for by a grant. After that, we will continue to push for a testing program run by the county.”
Another resident asked if extremely wet years, like the one we just had in 2018, have potential to increase the amount of water percolating into the groundwater, carrying nutrients from the surface with it.
“Wetter years can result in more water entering groundwater,” McGinley answered. “Water percolates into the ground, but then moves into the groundwater relatively slowly, so only some of the water in your well today is likely to be from recent rain events.”
McGinley went on to elaborate that the recent weather and floods, especially occurring as they did at the time of year when most of the crops were still in the ground, means that they were probably not a major factor in the nitrate results from the recent testing. He explained that the one exception would be in the immediate vicinity of a sinkhole or thin soils, where water can travel through the soil layer and penetrate into the fractured bedrock more quickly.
Viroqua resident Alicia Leinberger asked why the results didn’t contain a result for phosphorous.
“Our testing equipment does give a result for phosphorous,” Haucke responded. “But since phosphorous is not considered a human pathogen, we don’t include it in the testing results.”
McGinley said that the average amount of phosphorous in groundwater is very small, about 0.02 mg/L. This, he explained, is much lower than the results that are found in surface water.
Next meeting
The next meeting of the Tainter Creek Watershed Council will be held on Wednesday, Jan. 9, 12:30-2:30 p.m., at the Gays Mills Community Commerce Center Board Room.
Topics that will be on the January 9 meeting agenda include:
• Tainter Creek surface water quality report by Dr. John Delaney
• Planning for 2019 and how to use the $40,000 DATCP grant
• Discussion of a potential Wallace Center at Winrock International grant for modeling impacts of conversion to grass on phosphorous levels in surface waters
• Planning how to use a $10,000 ‘Cover Crop Champion’ grant in 2019. Ben Wojahn explained that one potential use would be to send some group members to the Wisconsin Cover Crop Conference taking place on February 20 in Stevens Point (the day before will be the DATCP’s session for producer-led watershed groups).
• Discussion of how to attract more farmers into the group.
