Sediment Transfer through the Fluvial System (Proceedings of a symposium held in Moscow, August 2004). IAHS Publ. 288, 2004, 370–376

Abstract A model to describe the spatial distribution of torrent bed type debris flows in alpine drainage basins was developed and validated by field measurements. In addition to the determination of debris flow initiation sites, process pathway and erosion and deposition zones were identified. Potential process initiation sites were derived from channel slope, upslope contributing area and a material contributing area. Process pathway and travel distance were modelled by a grid-based "random walk" in conjunction with a 2-parameter friction model and Monte Carlo simulation. Erosion and deposition zones were derived by threshold functions of channel gradient and modelled velocity. A high magnitude rainstorm event in 2002 in the Lahnenwiesgraben drainage basin was used to validate the model. It is suggested that the model output may be used for the investigation of spatially distributed sediment transfers and for natural hazard zonation.

Key words debris flows; deposition; erosion; friction model; natural hazard zonation; Northern Limestone Alps; random walk; sediment transfer; travel distance