Field observation on sand deposition on the gravel beach was carried out on the Jinkoji and Akashi coasts facing the Pacific Ocean. On the basis of the contour-line-change-model, a model for predicting sand deposition on the gravel beach under the calm wave conditions was developed, taking into consideration that the equilibrium slope of sand is increased due to the percolation effect of gravel bed and its effect depends on the thickness of sand layer. Furthermore, landward movement of gravel due to storm waves was explained by the model. Predicted results were in good agreement with measured values.
