Emilia-Romagna coastal sediment modelling and depositional patterns

Coastal erosion is a global problem that is projected to worsen in the context of climate change, thus prompting interest in the development of tools for predicting the coastal response to various climate scenarios. The Emilia-Romagna coastline is a case in point, and the present thesis aims to design a sediment transport model that represents the sediment dispersal patterns and the erosion and deposition patterns of the area. The numerical model used is SHYFEM-MPI, which uses a finite element method and works on unstructured triangular grids. The model offers a sediment transport module, that works with multiple sediment classes. Five distinct grain sizes are used in this thesis. To ascertain the most suitable model configuration, a sensitivity analysis was conducted. The findings revealed that the horizontal diffusion coefficient exerts minimal influence on sediment transport, and the most effective method for describing sediment transport is the Van Rijn method. A one-year simulation was conducted for the year 2019. The model demonstrated competence in depicting the along-shore sediment transport, which is the predominant transport pathway, albeit with lower concentrations than measured ones. This discrepancy is hypothesised to be attributable to an absence of sediment boundary conditions at the open boundary. Furthermore, during the flood event, the model exhibited a plume geometry that was analogous to the observed one. Following a year-long simulation period, the model exhibited erosion and deposition patterns analogous to the observed ones, and the grain size pattern began to mirror the local pattern. This thesis signifies the initial attempt to utilise a finite element model with multiple sediment classes on the Emilia-Romagna coast. The most significant challenge was the paucity of sediment data. To enhance this model further, it is recommended to take turbidity and discharge measurements at river mouths, and couple SHYFEM-MPI with a third-generation wave model.