|Spaeth, Kenneth - NRCS|
Submitted to: Society for Range Management
Publication Type: Abstract Only
Publication Acceptance Date: February 5, 2005
Publication Date: February 5, 2005
Citation: Moffet, C.A., Pierson, F.B., and Spaeth, K.E. 2005. Modeling soil erosion on steep sagebrush rangeland before and after prescribed fire. 58th Annual Meeting Society of Range Management, February 5-11, 2005, Forth Worth, TX. CD-ROM. Technical Abstract: The risk of significant erosion in many sagebrush rangelands is low even on steep (20 to 40%) slopes due to abundant canopy and ground cover. After fire, however, canopy and ground cover are significantly reduced and the risk of erosion is increased. The Water Erosion Prediction Project (WEPP), developed to model erosion on cropland and rangeland, is a likely tool for addressing erosion risk questions following fire. WEPP models interrill and rill erosion processes. Rangeland WEPP development experiments included only plots with slopes less than 15% and there was no evidence during these experiments that the rill erosion process occurred. Nonetheless, model optimization procedures were performed with these data to derive critical shear and rill erodibility parameter regression equations. Experimental results in steep (20 to 40%) sagebrush rangelands suggested that the potential for rill erosion was significant for several years following fire and that rangeland WEPP underestimated rill detachment in these systems. Improvements need to be made to WEPP relative to the rill erosion process before reasonable estimates of erosion risk can be made. Analysis of data from steep burned sagebrush rangelands showed that WEPP rill detachment estimates can improved by (1) using measured rather than regression-estimated values of rill erodibility and (2) improving algorithms related to the hydraulics of the rill flow. In this paper we report the effect of fire and recovery on measured soil erosion during simulated rainfall from large (32.5 m2) plots, explain proposed modifications to WEPP, and compare WEPP model estimated, modified WEPP estimated and measured soil erosion.