Modeling Alternative Agricultural Scenarios Using Rusle and GIS to Determine Erosion Risk in the Chippewa River Watershed, Minnestota

Abstract

The Land Stewardship Project (LSP), a Minnesota-based nonprofit organization, is working to quantify water quality, wildlife habitat, economic, and other benefits from working farmlands. Several approaches are being tested in this multi-disciplinary effort to further the growing demand for improved environmental outcomes from agriculture. From these analyses LSP can make recommendations for conservation program implementation and performance-based policies at the state and national level. At the core of this project is modeling research that predicts the benefits that could be produced by farming systems that aim to reduce erosion into nearby streams, which is a significant problem in the United States. LSP identified the need for a straightforward yet effective model to predict soil loss under varying agricultural scenarios. For this project, an assessment of the Revised Universal Soil Loss Equation (RUSLE) within ArcGIS was conducted as a means to predict erosion risk within Minnesota’s Chippewa River Watershed from nearby agricultural lands. Four alternative agricultural scenarios were developed to predict changes in erosion. Results show that increasing agricultural lands under conservation tillage, planting cover crops in cultivated areas, increasing the area under grassland, adding vegetated buffers along streams, and restoring wetlands resulted in the most dramatic decrease in erosion in the Chippewa River study area. A manual detailing data preparation, scenario development, and running the model was developed for LSP. Overall, the use of RUSLE within ArcGIS is an appropriate strategy for LSP’s work to identify erosion potential in agricultural areas and to identify and enhance various environmental and economic benefits from agriculture. Beyond modeling soil loss, LSP can use ArcGIS to identify and prioritize areas for monitoring, restoration, and for education and outreach programs.