Many water scientists are motivated by the idea that their research is societally relevant. This talk explores a state code change in Wisconsin, NR151, which regulates the spreading of manure on farm fields.  Various factors and events, spanning nearly 40 years, needed to align for that code change to become law.

Northeastern Wisconsin is underlain by the Silurian fractured-dolomite aquifer. Dairy farming and associated crop production comprise the primary land use, and manure is commonly applied to crop land. In areas where soils are thin, there is a history of "brown water" events in private supply wells that occur in response to groundwater recharge. The Wisconsin Geological & Natural History Survey (WGNHS) began researching the hydrogeology of the Silurian aquifer in the mid 1980’s; the code change went into effect in 2018. Initially the research focused on one county, but a brown-water event in a neighboring county in 2005 led to the creation of the Northeast Wisconsin Karst Force, which recognized the regional geologic nature of the issue and developed preliminary policy recommendations. The recommendations were strongly opposed by the dairy industry. However, the growth of concentrated animal feeding operations (CAFOs) led to the formation of an engaged group of citizen advocates who helped raise awareness of the issues and who were willing to litigate on the issue of an expansion of an existing CAFO. Research collaboration with microbiologists helped elucidate the extent and sources of contamination (human vs. bovine) and highlighted human health concerns. All of these factors came together in the Fall of 2016. A U.S Senator held a town hall in the region and the Wisconsin Department of Natural Resources convened a Technical Advisory Committee tasked with recommending changes to the NR151. Those changes, which call for reduced manure applications where the depth to rock is less than 20 feet, were finalized in 2017 and the rule went into effect in 2018.

Subsequently, the WGNHS, in collaboration with the United States Geological Survey (USGS) has received considerable funding to create better depth-to-bedrock maps for the region. At the same time, many of the CAFOs, perhaps recognizing a change in the regulatory landscape, have installed wastewater treatment facilities on their farms.