A GIS-BASED METHOD FOR PREDICTING SOIL EROSION ON MOUNTAIN BIKING TRAILS

As the popularity of mountain biking increases, concerns about trail degradation from soil erosion has increased, particularly on informal trails constructed with little or no erosion controls. We mapped a network of informal mountain biking trails in central New York State and used a GIS-based method that uses the Revised Universal Soil Loss Equation (RUSLE) with high-resolution elevation data to quantify potential soil erosion. We found that although RUSLE was created for large-scale agricultural fields, our method was useful for predicting potential soil erosion on the narrow biking trails. We tested our results by selecting random locations in three different erodibility categories and determining the actual soil loss by measuring the cross-sectional area of the eroded trail. We found good agreement between potential erosion rates that we identified using the GIS-based method and actual erosion from measurements of the cross-sectional areas of eroded soil. Furthermore, visual inspection of trail segments that our model showed to be highly erodible were clearly more degraded than trail segments with low calculated erodibility. Our method overestimated erodibility on trails that were ridden only in a downhill direction and failed to identify topographic lows where standing water accumulates and the resulting disturbance of the soil is severe. The method is relatively easy to use and can be used to manage and protect existing trails or as a planning tool to route trails away from susceptible areas before construction.