Quantifying sediment transfer between the front of an active alpine rock glacier and a torrential gully

The present contribution describes results from the quantification of transferred sediment volumes between the front of an active rock glacier and a torrential gully. The focus is set on the methodological approach which combines terrestrial laser scanning (TLS) generated digital terrain models (DTM) and geodetic field surveys. The aim is to compare high resolution DTMs from different dates in order to calculate volume gain and loss in the system for different time intervals. As the object of the study is a fast moving landform, other sources of information such as geodetic measurements (GPS) were necessary to estimate the advance of the rock glacier during the same time intervals and to facilitate the interpretation of the TLS data. It was then possible to estimate sediment budgets in the whole scanned area for different time intervals. The results show an extensive erosion of the front (up to 5000 m/year) but also the presence of a temporary sediment storage area in the upper part of the torrential channel.