Analysis of the impact of nautical tourism on the marine environment is hindered by the lack of systematic monitoring of vessel movements. This paper presents a spatial framework, based on a cell grid, for mapping Natura 2000 areas exposed to recreational boating pressures. The methodology integrates AIS-derived recreational vessel density, Natura 2000 coverage, and bathymetric characteristics within a grid-based framework to identify localized environmental exposure hotspots in coastal waters of the Adriatic. The developed index identifies areas where recreational boating intensity, Natura 2000 coverage, and shallow-water conditions spatially coincide. Sensitivity analysis confirms the model's robustness across different depths and weighting scenarios. Results reveal strong seasonal dynamics: the proportion of Natura 2000 areas in the High and Critical exposure classes increases from approximately 17.57% in winter to more than 23.02% in summer. This approach provides a basis for spatially focused management measures, such as anchorage regulation and the introduction of differentiated environmental fees.
This study combines two numerical models (LTC and CS-Model) into an integrated numerical framework, IODA (Integrated cOastal Dynamics Assessment). IODA is design for medium- to long-term (years) coastal modelling at regional scales, by coupling longshore and cross-shore sediment transport processes (sandbar-berm-dune dynamics), while balancing physical processes representation, computational efficiency and input data requirements. IODA was applied to the Costa Nova-Vagueira coastal sector, Portugal, an erosion hotspot where artificial sand nourishment is frequently implemented. The application was supported by five topo-bathymetric surveys covering the period 2018–2024, allowing a comparison between observed and modelled coastal evolution. The monitoring data revealed a highly dynamic coastal system, with alternating erosion and accretion patterns and distinct morphological responses to nourishment interventions. Model simulations indicate that coupling longshore and cross-shore sediment transport improves shoreline evolution predictions, compared with simulations considering longshore transport alone, while highlighting the influence of boundary conditions and anthropogenic sediment inputs on sediment redistribution. Overall, the application demonstrates the potential of IODA as a computationally efficient framework for medium- to long-term assessment of coastal evolution and provides insights into the processes governing the redistribution of nourished sediments. Although uncertainties remain, the results magnitude is consistent with those reported in recent multi-timescale shoreline modeling studies, underscoring the need for continued research in this field.
