Simulating beach and dune evolution at decadal to centennial scale under rising sea levels

by Caroline Hallin, Magnus Larson, Hans Hanson

A numerical model for simulating beach-dune evolution at decadal to centennial time scales is developed. The work builds on an existing semi-empirical cross-shore model, the CS-model, to which the effect of sea level rise is added and the routines for aeolian transport and morphological dune evolution are improved. The model development is based on established conceptual models from the literature, which are translated into mathematical formulations and solved numerically. The capability of the proposed model is demonstrated through a case study at Ängelholm Beach, Sweden. The model is calibrated and validated against a seven-year long data set on morphological evolution and sediment grain-size samples. Beach and dune evolution is then simulated from 2018 to 2100 for a range of sea level rise scenarios. The model results are promising, and suggest that the model has potential to be used for long-term assessment of climate change impact on beaches and dunes.