Monitoring the Effectiveness of Best Management Practices in the Whitewater

Soil erosion, due to intensive agricultural practices, has been and continues to be of significant concern in the Whitewater Watershed, a coldwater tributary of the Mississippi River, in southeastern Minnesota. Conservation efforts, in the form of best management practices (BMPs) have been underway for many years and a number of residents have enrolled in various government programs designed to reduce soil loss. However, the effectiveness of these programs is unknown. As it stands, participation in such programs is voluntary and efforts have been non-targeted, resulting in a random and noncontiguous distribution of conservation practices. In addition, many of the practices implemented are designed to reduce soil loss that occurs during an average annual rainfall event. However, studies conducted over extended periods of time (decades) have shown that as much as 60% of total soil erosion occurs during single, infrequent severe rainfall events (Larson, 1997). Therefore, the majority of traditional BMPs aimed at reducing soil loss, which manage only for average annual rainfall, are leaving soil vulnerable to stochastic infrequent storms. A better, and more quantitative, understanding of the effectiveness of such activities is necessary if we are to protect the watershed, and all that flows downstream of it. The Logan Branch of the Whitewater Watershed was selected to be used in a pilot project, managed by the federal Environmental Protection Agency and the Minnesota Pollution Control Agency, to quantify the effectiveness of BMPs implemented under the current enrollment strategy. It is the goal of this paper to report on the selection criteria used to identify the Logan Branch for this pilot project. A model was created based on six criteria dealing with soil erodibility, landuse/landcover, land mass, intensity of current conservation program participation, density of hydrologic and biological sample sites and the potential impact conservation land practices would have on soil conservation. Data for this spatial analysis were obtained from the Whitewater Watershed Project. Based on the given criteria the Logan Branch was identified as the most appropriate subwatershed for the BMP effectiveness pilot project. Geographic Information Systems (GIS), which was used to perform the siting analysis, proved to be an extremely effective tool. The Whitewater Watershed Project (Watershed Project), a collaborative group made up of participants from various local, state and federal agencies, as well as watershed citizens are currently applying GIS technology extensively throughout the watershed and believe it to be an extremely effective tool for holistic watershed management. The technology has been used to improve management efforts within the watershed. It has been used for such things as identifying habitat fragmentation and implementing conservation practices aimed at