high-gradient channel; sediment budget; dendrogeomorphology; bedload transport modeling; flysch

Detailed quantification of material supply into stream channels is crucial for determining sediment (un)balance budget during flood events. Unfortunately, existing quantification methods require long-term field monitoring; otherwise, there is an insufficient amount of usable data. In this study, we introduce a new approach, based on dendrogeomorphic methods, to determine the volume of material supply generated from flysch high-gradient stream bank failures. This approach was supplemented by 1D sediment transport modelling, using a TOMSED model. We analysed 138 cross-sections from the roots of predominantly broad-leaved trees, which were exposed in bank failures from different floods. Using the spatial position of the roots and dating the exposure time, we determined the volume of material supply into the channel during the last flood, in 2010.