Effectiveness of Barnyard Best Management Practices in Wisconsin

In 1978, the Wisconsin Legislature committed to protecting water quality by enacting the Nonpoint Source Water Pollution Abatement Program. Through this program, cost-share money is provided—within priority watersheds—to control sources of nonpoint pollution. Most of the cost-share dollars for rural watersheds have been used to implement barnyard Best Management Practices (BMPs) because barnyards are believed to be a major source of pollutants, most notably phosphorus. Reductions in phosphorus loads of as much as 95 percent have been predicted for the barnyard BMPs recommended for priority watersheds. Previous studies of barnyard BMPs have often focused on individual BMPs, such as a filter strip below a concrete feedlot. Study results have been sufficient to predict the potential benefits of several individual barnyard BMPs, and the combined benefits of these BMPs have been estimated with the computer model BARNY (Wisconsin Department of Natural Resources, 1994). The output from the model has been used to develop management recommendations for phosphorus reduction in priority watersheds. The best way to evaluate the true benefits of a combination of barnyard BMPs is to monitor changes in the receiving water. However, very little information has been collected in Wisconsin to document such benefits. The U.S. Geological Survey (USGS), in cooperation with the Wisconsin Department of Natural Resources, investigated the effectiveness of barnyard BMPs in two rural watersheds—Otter Creek and Halfway Prairie Creek. The purpose of this investigation was to determine how much pollutant reduction could be achieved by a system of barnyard BMPs. An upstream-downstream (above-and-below) experimental design was used to isolate the pollutant loads coming from a critical barnyard on each creek. Automated, intensive streamwater sampling was conducted during storm-runoff periods before and after the BMP systems were implemented. The concentrations of selected constituents in the streamwater samples and streamflow data were used to compute loads for the constituents contributed to the creeks by each barnyard during preand post-BMP storm-runoff periods. The data were analyzed to determine how effective each barnyard BMP system was in improving water quality. Description of Study Area