Distributed modelling of erosion and sediment delivery to drainage

Evaluating hillslope sediment supply to stream channels and hillslope-channel feedback mechanisms is a key step for a proper sediment management. In this study, a distributed modelling approach will be applied to explore sediment dynamics (erosion, transport, deposition) along hillslopes and to estimate the sediment export to the drainage network due to landsliding. For the purpose, the open-source software LANDPLANER will be used. Such tool is built upon a distributed hydrological modelling procedure and uses a simplified set of input data, namely (i) a slope and an accumulation map derived from a DEM, (ii) meteorological data, and (iii) a Curve Number map derived from land use/cover and soil maps based on SCS method (https://www.nrcs.usda.gov/). LANDPLANER estimates primarily the repartition of rainfall into infiltration and runoff and secondarily the related sediment erosion, transport and deposition. The tool will be applied in small basins located in the central/northern sector of the Apennine chain. The model will be set up and calibrated in the different specific study area conditions, using benchmark data. Effectiveness of calibrations depends on the type, quality and accuracy of the benchmark data. Multiple calibration approaches will be tested, accounting for the presence of landslides on hillslopes and their possible sediment supply. The calibrated model will be used to estimate the dynamic water and sediment connectivity in relation to specific rainfall and landslides spatio/temporal patterns and to site-specific land use, vegetation and soil conditions. Scenario-based simulations will evaluate sediment dynamics for real/plausible basin managements in response to varying natural and/or anthropogenic forcings.