A Near-Shore Wave Monitoring Model for Beach Planform Evolution Prediction

Coastal erosion is a serious problem affecting a growing number of sites worldwide. Frequently, the erosion is caused by long-shore drift currents induced by sea waves in the surf zone. Many formulas have been proposed by researchers in order to estimate the mean rate of sediments moved annually alongshore by waves. In the present paper, the authors describe a revised model for predicting the long-shore drift current. The model is based on directional wave analysis by means of measurements of the instantaneous sea surface elevation operated simultaneously by three altimeters closed each othe in a non-colinear configuration. Such information is used to characterize the waves forming a sea state. Time series measurements of water surface elevation are analysed. So directional wave spectrum is computed in order to predict the mean angle of advance of waves. The model has been improved and optimized by considering the effect of measurement uncertainty in the wave direction estimation. As a consequence, the wave propagation direction is accurately evaluated so to produce a reliable prediction of the long-shore current.