Modelling long-term shoreline evolution in highly anthropized coastal areas. Part 1: Model description and validation

This study presents IH-LANS (Long-term ANthropized coastlines Simulation tool), a numerical model for addressing long-term coastline evolution at local to regional scales in highly anthropized coasts. In IH-LANS, a hybrid (statistical-numerical) deep-water propagation module and a data-assimilated shoreline evolution model are coupled. Longshore and cross-shore processes are integrated together with the effects of man-made interventions. For every simulation, shoreline changes in response to time varying wave conditions and water levels are evaluated while reducing calibration uncertainty by means of an extended Kalman filter that allows to assimilate shoreline observations. To test model performance, IH-LANS is applied to a highly anthropized 40 km stretch located along the Spanish Mediterranean coast. The model is run during the period 1990-2020 using high space-time resolution climate data and satellite-derived shorelines in order to calibrate the free parameters and validate model outputs. Shoreline evolution is successfully represented (<10 m of root mean square error, RMSE) while accounting for the effects of nourishments and the construction and removal of groynes, seawalls and breakwaters over time. The efficiency of the model makes IH-LANS a powerful tool for coastal management and climate change adaptation.