Sensitivity analysis of climate change impacts on dune erosion: case study for the Dutch Holland coast

Climate change could have large implications for the management of dune-fringed coasts. Sea level rise and changes in storm wave and surge characteristics could lead to enhanced dune erosion and hence a decrease in safety levels. Here, we use the process-based model XBeach to quantify the impact of sea level rise and changing hydrodynamic boundary conditions on the magnitude of future dune erosion at two locations along the Dutch coast. We find a linear relation between sea level rise and dune erosion volume, the exact linear relation being dependent on the local hydrodynamical boundary conditions. The process driving higher erosion appears to be sea level rise, allowing waves to attack the dune at a higher level. Additional simulations illustrate that a change in the offshore wave angle, potentially produced by changes in storm tracks, could influence the erosion volume with the same order of magnitude as sea level rise. Finally, simulations with different mitigation options (i.e., sand nourishments) illustrate the strong effect of the location of the added sand to the reduction in the dune erosion volume.