Evolution model of shoreline position on sandy, wave-dominated beaches

Abstract

In this study, we derived an ordinary differential equation governing temporal changes in shoreline position by analyzing the horizontal behavior of suspended sediment due to storm waves. The derived governing equation has a mathematical form similar to that of current empirical models. However, because the equation was derived physically, it clearly reveals the characteristics of each physical coefficient. Therefore, coefficient estimation using the derived equation improves the accuracy of the model results. The model was applied to wave and shoreline data of Tairua Beach, New Zealand for a period of 11 years; the results confirm that the model has satisfactory field applicability. Further, we observed that the model accuracy with respect to the shoreline position extracted from video images, improved when the wave setup effect was considered. The degree to which the wave setup affects the improvement in model accuracy is evaluated by correlation and spectral analysis of the observed and predicted shoreline positions. This study provides a clear theoretical background for shoreline models and improves the prediction accuracy and model generality.