Numerical Approaching of Beach Profile Change by Suspended Sediment Transport Process

The coastal process in a surf zone is very complicated, especially when the wave breaks and it associates turbulence. In a coastal area with wave angle influence the cross-shore process, the energy dissipated per unit water volume by breaking waves generate seabed sediment suspension then drive the materials to offshore along with the undertow in the swash zone. This situation could lead beach profile evolution due to the sediment erosion and deposition across an area in the surf zone. As a result, a sand bar located around the breaking line and berm at the landward region caused by overwash are formed. Furthermore, the beach profile is presumed to be in an equilibrium condition when the total positive and negative littoral transport approaches zero. The equilibrium stage which commonly used is expressed with a power of 2/3 which provide the best representative to the natural beach profile shapes. Under this concept, an analysis on the correlation between the beach profile response due to the incident wave energy and suspended sediment transport in a cross-shore view is carried out. Furthermore, this study develops a simple equilibrium beach profile prediction by analyzing the sediment characteristics and is supported by numerical modeling. Lastly, this study is expected to be practically used for coastal infrastructure design works, especially in the process of mean shoreline position prediction as the basis of the design judgements.