Soil erosion by snow gliding – a first quantification attempt in a sub-alpine area, Switzerland

Abstract

Abstract. Snow processes might be one important driver of soil erosion in Alpine grasslands and thus the unknown variable when erosion modelling is attempted. The aim of this study is to assess the importance of snow gliding as soil erosion agent for four different land use/land cover types in a sub-alpine area in Switzerland. We used three different approaches to estimate soil erosion rates: sediment yield measurements in snow glide deposits, the fallout radionuclide 137Cs, and modelling with the Revised Universal Soil Loss Equation (RUSLE). The RUSLE model is suitable to estimate soil loss by water erosion, while the 137Cs method integrates soil loss due to all erosion agents involved. Thus, we hypothesise that the soil erosion rates determined with the 137Cs method are higher and that the observed discrepancy between the soil erosion rate of RUSLE and the 137Cs method is related to snow gliding and sediment concentrations in the snow glide deposits. Cumulative snow glide distance was measured for the sites in the winter 2009/10 and modelled for the surrounding area with the Spatial Snow Glide Model (SSGM). Measured snow glide distance ranged from 2 to 189 cm, with lower values at the north facing slopes. We observed a reduction of snow glide distance with increasing surface roughness of the vegetation, which is important information with respect to conservation planning and expected land use changes in the Alps. Our hypothesis was confirmed: the difference of RUSLE and 137Cs erosion rates was related to the measured snow glide distance (R2= 0.64; p < 0.005) and snow sediment yields (R2 = 0.39; p = 0.13). A high difference (lower proportion of water erosion compared to total net erosion) was observed for high snow glide rates and vice versa. The SSGM reproduced the relative difference of the measured snow glide values under different land uses and land cover types. The resulting map highlighted the relevance of snow gliding for large parts of the investigated area. Based on these results, we conclude that snow gliding is a key process impacting soil erosion pattern and magnitude in sub-alpine areas with similar topographic and climatic conditions.

The role of the soil seed bank for the restoration potential of eroded alpine grassland

“…In the Alps, shallow erosion on grassland is a widespread phenomenon (Wiegand & Geitner 2010;Meusburger & Alewell 2014;Geitner et al 2021). In recent decades, some areas experienced increased rates of shallow erosion.…”

Soil erosion in an avalanche release site (Valle d'Aosta: Italy): towards a winter factor for RUSLE in the Alps

“…Complex soil profile morphologies may occur along an avalanche path with both buried and truncated soil horizons. Snow gliding phenomena can contribute significantly to soil erosion at the snow-soil interface as shown by Meusburger et al (2014), who identified snow gliding as a relevant driver for winter soil erosion in the Swiss Alps. Despite the first try by Konz et al (2009) at including a winter factor in the RUSLE, the incidence of snow-induced erosion on large scales (e.g., catchment or avalanche areas) cannot be evaluated with a well-defined standard procedure.…”