Ecological - Second Order
Fire in sagebrush rangelands significantly alters canopy cover, ground cover, and soil properties that influence runoff and erosion processes. Runoff is generated more quickly and a larger volume of runoff is produced following prescribed fire. The result is increased risk of severe erosion and downstream flooding. The Water Erosion Prediction Project (WEPP), developed to model erosion on cropland, forest, and rangeland, is a tool that has the potential to model erosion and help managers address erosion and runoff risks following fire. WEPP views erosion as two processes: interrill and rill. Experimental results on a steep (35 to 50 percent slope) sagebrush site suggest that rill erosion is the dominant erosion process following fire and must be adequately understood so that models can provide reliable predictions. Evaluation of WEPP parameterization equations using data from steep burned sagebrush rangelands suggests that critical parameter estimation procedures within WEPP need improvement to include fire effects on infiltration and rill erosion processes. In particular, rill detachment estimates could be improved by modifying regression-estimated values of rill erodibility. In addition, the interactions of rill width and surface roughness on soil grain shear estimates may also need to be modified. In this paper we report the effects of prescribed fire on runoff and soil erosion and compare WEPP estimated erosion for several modeling options with measured erosion.