Sand nourishment strategies to mitigate coastal erosion and sea level rise at the coasts of Holland (The Netherlands) and Aveiro (Portugal) in the 21st century

Coastline retreat is an evident sign of the vulnerability of low-lying sandy coasts to erosion and sea level rise (SLR). Sand nourishments are commonly used to maintain foreshores, beaches, and dunes to preserve their role in flood protection, beach recreation and biodiversity. The feasibility of sand nourishments for long-term maintenance of large-scale coastal systems is hard to determine with detailed numerical morphological models. This study presents a method using a sand nourishment impact model (Ntool) that accounts for repeated sand nourishments over time as well as erosion and SLR impacts on the shoreline position. In Ntool the redistribution of sediment alongshore is based on detailed simulations of the current situation of waves (Delft3D-WAVE) and shoreline development (UNIBEST-CL+).