Integrated modelling of hydrodynamics, vegetation and coastal morphodynamics in the Adriatic and Tyrrhenian Seas

This study presents an advanced, integrated numerical framework designed to resolve the non-linear interactions between hydrodynamics, aquatic vegetation, and coastal morphodynamics. Unlike traditional decoupled approaches, this framework captures the complex feedback governing momentum transfer, kinetic energy dissipation, and vegetation-mediated sediment trapping, processes vital for understanding coastal resilience under the pressures of Mediterranean sea-level rise and intensifying storm surges.

 

The modeling suite is built upon the SHYFEM-MPI finite-element circulation model, into which a novel morphodynamic module has been integrated, and coupled with spectral wave modle WAVEWATCHIII. This module incorporates state-of-the-art formulations for bedform transport and secondary current effects in stratified and channelized flows. To ensure physical consistency, the circulation engine is coupled with a spectral wave model via a shared unstructured computational grid, thereby eliminating interpolation-induced numerical diffusion and ensuring a synchronous exchange of wave-induced radiation stress and current-driven forcing fields. To overcome the chronic scarcity of in-situ sedimentological data, the study employs multi-sensor satellite-derived products to prescribe boundary conditions and provide independent spatio-temporal benchmarks for model validation. Furthermore, a variational data assimilation approach is utilized for bathymetric reconstruction, merging high-resolution local surveys with global datasets to generate a seamless, multiscale digital elevation model.

 

The framework application is demonstrated through idealized benchmarks and regional applications in the northeastern Tyrrhenian and Adriatic Seas. The results quantify the mechanistic partitioning between bedload and suspended sediment transport and demonstrate how evolving seabed morphology actively modulates local circulation and sea-surface elevations. This fully coupled approach provides a sophisticated tool for assessing the long-term morphodynamic trajectory of Mediterranean coastal systems.