Satellite-based shoreline dynamics of repeatedly nourished Dutch beaches with contrasting directional wave climates

Beach and shoreface nourishments are widely used to mitigate erosion of sandy coasts. Since 1990, large stretches of the Dutch coast have been repeatedly nourished, with efforts expected to increase further. However, the cumulative effects of repeated sand nourishments on coastal evolution remain poorly understood. This study uses satellite imagery to quantify how repeated nourishments have influenced shoreline dynamics and long-term trends between 1985 and 2025 at two sites with contrasting wave climates: (1) Egmond-Bergen, with a bimodal directional wave climate and limited net alongshore transport and (2) Ameland, dominated by a single prevailing wave direction and stronger alongshore transport. The two sites showed distinct responses to the repeated nourishments. At Egmond-Bergen, shoreface nourishments produced a cumulative but localised effect on the shoreline, leading to a positive trend of almost 2 m/yr. In contrast, shoreface nourishments at Ameland barely affected the shoreline, presumably because of the high alongshore transport. Beach nourishments at both sites, when not combined with a shoreface nourishment, only affected the shoreline temporarily (