Lay summary

This research project aims to quantitatively assess the variability in sediment yields in mountain basins across a range of timescales. There are two main aims:

(1) A data-driven conceptual modelling framework for sediment production, transfer, yield and their interactions is being developed. A systematic modelling framework will allow us to develop testable hypotheses about sediment dynamics in mountain basins, to objectively evaluate the sensitivity of different components of the system, and to analyse possible scenarios in climatic driving forces. Within this framework we will be able to address questions of space and time scales in sediment delivery and the role of landscape connectivity.

(2) The modelling framework is applied to the Illgraben basin, where a multidecadal scale dataset of over 2500 slope failures (landslides and rockfalls) has been developed within this project by digital photogrammetry. Hillslope and channel sediment resident times have been estimated and a dataset of debris flows elaborated. We aim to show that the stochastic nature of precipitation and other climatic variables together with the state of sediment stored in the system determine the debris flow dynamics in the basin and may be able to explain long-memory effects and complex response which are not obvious from observations of sediment yield alone.