A shoreline evolution model considering the temporal variability of the beach profile sediment volume (sediment gain / loss)

The prediction of shoreline variability along sandy coastlines is a valuable skill for a broad range of coastal engineering applications. Currently, there are multiple proposals in the literature for equilibrium cross-shore shoreline evolution models based on a constant equilibrium condition correlated with the shoreline position. The aim of this paper is to present an extension of an existing equilibrium shoreline evolution model adding a rate of change component, which in turn modifies the relationship between the equilibrium shoreline position and the incident wave energy, as a function that advances or retreats over time. The proposed model is applied to two study sites on the Spanish coast. On the one hand, one and a half years of shoreline position data obtained from a video camera system at Nova Icaria Beach, Catalonia, are used to evaluate the shoreline evolution during a period of sediment contribution, which is attributed to a sand bypass coming from Bogatell Beach. On the other hand, 16 years of shoreline position data acquired from beach profile surveys in Campo Poseidón, Huelva, are used to reproduce the shoreline evolution, taking into account the trend of sediment loss due to sediment drift alongshore. The results obtained from both study sites using the proposed model show overall good performance. The model successfully represents the general shoreline erosion–accretion oscillations and the progressive trend of sediment gains or losses through the evolutionary relationship between the equilibrium shoreline position and the incident wave energy. •An equilibrium shoreline evolution model adding a rate of change component is presented.•The EEF must evolve over time on beaches subjected to sediment deficit or surplus.•The proposed model successfully represented the shoreline evolution at two study sites on the Spanish coast.