Monitoring and modeling slope dynamics in an Alpine watershed – a combined approach of soil science, remote sensing and geomorphology

Abstract. Steep and unvegetated slopes in mountainous areas play an important role in erosion research as they deliver large quantities of sediments to the lowlands. However, their complex hydrological process combinations are challenging for any modelling and forecasting intention. Due to its high morphodynamic activity the Lainbach valley in southern Bavaria, Germany, has repeatedly been subject to studies on erosional processes. We present a further developed approach of physically based erosion modelling on strongly inclined and heavily dissected slopes. Model parameters were spatially and temporally distributed and a statistical model was tested to compare both findings to a previous study in the same catchment on a different slope. High resolution surface models from laser scans served as validation for the modelling results and for monitoring soil loss. Especially an adjustment of hydraulic roughness values improved the results, whereas rill hydraulics demand further investigation for future model development. The study at hand focusses on the summer period and reveals adequate modelling results (98.4% agreement in volume loss) with regard to the slope's non-stationary behaviour but leaves room for improvement for the winter period.