SIMULATION OF SORTING IN THE CROSSSHORE DIRECTION AND TOPOGRAPHY CHANGE OF THE BEACH COMPOSED OF MIXED BED MATERIALS BY SBEACH TYPE MODEL

Abstract

Numerical models for predicting topography change caused by sediment transport so far are generally carried out by using representative grain size. But actually bed material in the field often has wide grain size distribution. In a beach where grain size distribution is wide, the direction of bed material transport depends on its grain size because the mode if transport of fine bed material is different from that of coarse bed material in the cross-shore direction every now and then. The purpose of this study is to simulate sorting process of the bed materials in the cross-shore direction due to difference of transport direction between fine and coarse materials and topography change by applying SBEACH model. Simulated grain size distributions gave qualitative explanation for the observed one by the hydraulic model tests.