Satellite-Based Analysis of Shoreline Evolution along Wave-Dominated Deltas of the Catalan Coast (1984–2025): From Annual to Monthly Temporal Scales

Coastal areas are dynamic environments shaped by the interplay of waves, sediment supply, and human activities, making them highly sensitive to environmental change. One of the most vulnerable coastal systems are deltas, where dam construction along river courses has significantly reduced sediment delivery to delta fronts, and coastal infrastructures have altered natural dynamics. This study investigates the multi-decadal shoreline evolution of three large wave-dominated deltas along the Catalan coast (NW Mediterranean Sea) from 1984 to 2025: Tordera, Llobregat, and Ebro.

In this study, we used the CoastSat toolkit to analyze historical Landsat 5, 7, 8, and 9 (at 15 m resolution) together with Sentinel-2 imagery (at 10 m resolution) to extract shoreline positions. This multi-sensor approach enables the detection of long-term shoreline trends while also capturing seasonal and event-driven variations.

Our work highlights differential patterns of shoreline change across the  adjacent deltas beaches. The results  reveal the timing and magnitude of seasonal erosion and accretion processes, providing insight into short-term dynamics that are not evident in annual assessments. This integrated dataset demonstrates the value of combining multi-sensor satellite data with automated shoreline extraction tools for continuous monitoring of coastal evolution. Our findings contribute to the understanding of deltaic responses to wave climate, sediment supply, and human impacts, offering a robust framework for future coastal management and risk assessment strategies in Mediterranean wave-dominated delta systems.

 

This work has received funding from EBRO-CLIM research project PID2024-155310OB-I00 financed by MICIU/AEI/10.13039/501100011033/FEDER, UE.