EXPERIMENTAL STUDY ON ON-OFFSHORE SEDIMENT TRANSPORT OF ACCRETIVE BEACH

In treating coastal proceses, sediment transport is usually divided into along-shore and on-offshore components. It is believed that the on-offshore component has a prominant connection with short-term profile changes, observed during storm wave climates. Obviously its shift of sand plays a very vital role in shoreline migration. In other words, the beach profile has great bearing on coastal phenomena related to on-offshore sediment transport. As we know, there have been many studies on this kind of sediment transport rate, and considerable amount of knowledge on this problem has been accumulated so far. Yet it seems that we are still far from a reliable formulus to estimate the beach profile changes. The reason why is due to the complexity of mechanics of sediment transport. Therefore, the aim of this study is to examine experimentally the mechanism between onoffshore sediment transport and the deformation processes of twodimensional beach profile. Then , a predictive model of the temporal and spatial distribution of net on-offshore sediment transport based on two-dimensional beach profiles and an equation of continuity of sediment transport is proposed. Various parameters of net on-offshore sediment transport in this model are discussed also.