Changing Farming Practices in the Pecatonica is Getting Results

Targeted approach to improving water quality in the Pecatonica River watershed resulted in 55 percent decrease in phosphorus in stream during storm events.

For Mark Peterson, farming is a family affair. The land south of Mt. Horeb where Mark owns a dairy was homesteaded by his great-grandfather’s wife in the late 1800s. His father Paul, who farmed the land before him, still helps out, and Mark’s cousin Steve owns the farm next door, which he took over from his father. With just 48 milking cows, Mark operates one of only a handful of small dairy farms in the area.

“I think we’ve survived over the years,” Mark said, “because we’re not afraid to try new things.”

One of the challenges facing Mark and other farmers in Wisconsin and nationwide is keeping sediment, phosphorus and other nutrients on the land and out of lakes and streams.

Too much phosphorus leads to excessive algae growth, which blocks sunlight from underwater plants and consumes oxygen in the water. Toledo, Ohio’s ban on drinking water from Lake Erie in August 2014 is a worst case example of what can happen when phosphorus levels get so high they trigger harmful algae blooms that contaminate the water with toxin levels exceeding those deemed safe by the World Health Organization.

In 2006, The Nature Conservancy began working with farmers and other partners to test a new approach to reducing phosphorus and improving water quality in streams. Ten years later, monitoring results show a 55 percent decrease in phosphorus loading during storm events, a clear indication that targeting the application of conservation practices on agricultural lands with the highest estimated phosphorus runoff to streams, rather than randomly throughout a watershed, will result in cleaner water.


Bypassed by the glaciers, the Driftless Area in southwest Wisconsin is characterized by steep-sided ridges and miles of rivers and smaller tributary streams that eventually drain into the Mississippi River.

For the past 10 years, University of Wisconsin and U.S. Geological Survey scientists, public agencies and the Conservancy have been working with 11 farmers, including Mark Peterson, to test whether or not water quality in the Pecatonica River watershed in the Driftless Area can be improved by targeting conservation practices on those fields and pastures with the greatest potential for contributing phosphorus to streams.

Using research by a University of Wisconsin-Madison graduate student and Dane County Land and Water Resources Department staff, the partners identified a small number of farms in the Pleasant Valley Branch watershed, a tributary to the Pecatonica River, that were contributing comparatively large amounts of phosphorus to the stream.

Dane and Green County Land and Water Conservation staff worked with farmers to identify alternative management practices that would reduce sediment and phosphorus loss, including reducing tillage, changing crop rotations and manure handling methods, and installing livestock stream crossings and barnyard run-off systems. During three growing seasons from 2010 to 2012, farmers made targeted changes to management practices on about one-third of the crop and pasture land in the project area.

On Mark Peterson’s farm, for example, most of the changes were designed to keep his cows away from the stream and improve manure handling in his barnyard.

“The new barnyard system we developed for Mark allows him to keep his cattle on the feedlot longer and capture more manure, which he can apply on his fields,” said Duane Wagner, soil and water conservationist with the Dane County Land and Water Resources Department. “It will help reduce his dependence on commercial fertilizer and save him money in the long run.”

Because changing management practices can have financial implications, University of Wisconsin Extension researchers helped some of the farmers assess the financial costs associated with implementing various management practices. The partners secured funding from the Natural Resources Conservation Service and other sources to help farmers implement needed changes.


“We thought it would take several years after conservation practices were fully implemented to begin to see results, but because we identified the highest-contributing areas in the watershed and were able to address most of them, it happened more quickly than we expected,” said Steve Richter, Nature Conservancy director of conservation in agricultural landscapes.

Four years after all practices were installed, water quality data gathered by the U.S. Geological Survey show a 55 percent decrease in phosphorus loading during storm events in the Pleasant Valley Branch compared to a second control watershed nearby where no action was taken. The partners can say with 95 percent confidence that the change is due to conservation practices being put in place.

“The improved water quality in this watershed has a substantial cumulative effect downstream,” Richter said. “For example, on just one warm spring day with steady rainfall, this watershed now exports about 225 pounds of phosphorus, 275 pounds less than it would have if the conservation practices had not been put in place. That extra 275 pounds of phosphorus is no longer over-fertilizing the river and potentially producing 137,500 pounds of algae in downstream waters.” During storm events, we now also have a median load of 1.8 tons less sediment entering the river.”

State biological assessments showed improved conditions in the stream for fish as well as insects and other aquatic macroinvertebrates. More sensitive fish species that are less tolerant of pollution and disturbed habitat, such as brook trout, brown trout and mottled sculpin, are present. The Wisconsin Department of Natural Resources has proposed removing Pleasant Valley Branch from the EPA list of sediment-impaired streams.

“Targeting conservation practices to improve water quality seems straightforward,” Richter added. “But it’s actually a new approach to water quality improvement that is not currently being utilized in the United States. We believe the results we’re seeing in the Pecatonica River watershed can help change the way we clean up Wisconsin’s waters.”

For a fact sheet with more results from the project, click here.


Stay Updated

Learn about the places you love and find out how you can help by signing up for Nature eNews.

I'm already on the list Read our privacy policy

Thank you for joining our online community!

We'll be in touch soon with more Nature Conservancy news, updates, and exciting stories.