Debris-flow reconstruction and modelling at Ritigraben

Tree-ring data on the frequency, spatial dynamics and the flow behavior of previous debris-flow activity in the Ritigraben torrent (St. Niklaus and Grächen; also see past projects) are used to model events that have affected the intermediate cone over the last fifty years. We therefore use the debris-flow module of the 2D RAMMS: model. The model uses Voellmy-Salm equations and allows the definition of departure zones as well as the uptake of material along its path. The simulation runs are performed with a DEM created from a series of aerial photographs from 1958 and with recent LiDAR data, providing resolutions between 1 and 10 m. Due to the huge amount of reconstructed data available for the Ritigraben torrent, we hope to be able to enhance the RAMMS: model itself as well as to improve the overall understanding of debris-flow dynamics in the Ritigraben torrent. First results should be available by mid 2008.


Collaborations: Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf; Applied Geomorphology and Natural Risks Group (AGNAT), Institute of Geography at the University of Berne (GIUB), Bern

Project duration: November 2007 – December 2008

Contact : Markus Stoffel