Satellite-driven multi-scale approach for shoreline trend analysis in Mainland Portugal

Abstract

Mainland Portugal has approximately 415 km of low-lying sandy coastline, 45% of which show an erosion trend. In order to quantify the shoreline trends, the CASSIE (Coastal Analyst System from Space Imagery Engine) tool and Sentinel-2 images (2015-2023) were used to generate the shoreline position, which
were analyzed at three administrative scales: national, regional, and municipal. Results indicate that 41% of sectors are stable, 31% accreting, 19% eroding, and 9% critically eroding. Ovar municipality shows the highest average erosion rate (-2.6 m/yr), encompassing some of the beaches experiencing the most critical coastal erosion rates.