Location: Northwest Watershed Management Research
Title: Surface roughness effects on concentrated flow erosion processes in rangelands pre- and post-fire Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 11, 2011
Publication Date: November 14, 2011
Citation: Eitel, J., Williams, C.J., Vierling, L., Al-Hamdan, O.Z., and Pierson, F.B. 2011. Surface Roughness Effects on Concentrated Flow Erosion Processes in Rangelands Pre- and Post-Fire. In: Abstracts of the Association for Fire Ecology Interior West Conference, November 14-17, 2011, Snowbird, UT. Technical Abstract: Concentrated flow erosion is a major mechanism of soil erosion on disturbed rangeland hillslopes and is strongly influenced by surface roughness. In this study we evaluated the utility of terrestrial laser scanning (TLS) to assess effects of surface roughness on concentrated flow erosion processes on burned rangeland hillslopes in Idaho, USA. Surface roughness of the burned surface on 8.5 m2 field plots was quantified at the sub-cm level using a field-portable TLS device before and after concentrated flow experiments. Local surface roughness was calculated as the standard deviation of TLS mapped surface heights within moving windows varying in size from 30x30 to 90x90 mm. Concentrated flow was simulated on field plots by releasing concentrated flow at rates of 15, 30, and 45 L min-1. Each flow release on each plot was applied for 12 min from the same release-point location, 4 m upslope from a runoff collection point. Release rate progression was consecutive from 15 L•min-1 to 45 L•min-1. Concentrated flow erosion was negatively correlated with flow path or local surface roughness and the roughness-erosion relationship was affected by the moving wind size, emphasizing a scale dependence of the roughness-erosion relationship. Our results indicate that TLS is a useful tool to enhance our current understanding of the effect of surface roughness on overland flow erosion processes and to advance hydrologic and erosion model parameter development for simulating erosion processes on disturbed rangelands.