Groundwater Hydrogeology of an Agricultural Watershed

Summary: Wisconsin is fortunate to have outstanding groundwater resources. But increasingly these resources are being stressed. The most obvious stresses involve contamination from a variety of sources, including septic systems, landfills, underground tanks, and agricultural chemicals. In addition, the amount of available groundwater is gradually being reduced. The greatest threat to groundwater quantity is urban expansion, which typically results in increased pumping and decreased recharge.

Our ability to effectively manage each of the various stresses to groundwater quality and quantity depends to a large extent on our ability to understand and quantify groundwater flow systems, particularly with respect to the spatial distribution of groundwater recharge. The goal of the research reported here was to improve our understanding of the spatial distribution of groundwater recharge in the Driftless Area of southwestern Wisconsin. In particular, we focused on the Black Earth Creek and Garfoot Creek watersheds and the Sugar River watershed, adjacent watersheds in western Dane County. In addressing the issue of groundwater recharge, we considered two problems. The first was to determine the relative contribution of various landscape elements to groundwater recharge. The second was to explore the extent to which there were differences between the groundwater and surface-water divides.