Engineering Approaches to Cross-Shore Sediment Transport Processes

Abstract

In this chapter we consider beach profile and cross-shore sediment transport processes commonly encountered in coastal engineering applications. Main emphasis is on beach profile change produced by direct wave action, and our assumption will be that longshore transport processes are constant along the profile. Present engineering knowledge of cross-shore transport processes draws heavily on conceptual models that simplify the target problem to a manageable state that is hoped represents the essence of the phenomenon. The engineer should be aware of both the strengths and limitations of these simplifying techniques and models used. Such engineering approaches will be described here. Example calculations for selected topics are presented to show the applications of the material presented here. At present, approaches that isolate cross-shore and longshore processes are highly fruitful and appropriate owing to our limited understanding of nearshore hydrodynamic sand sediment transport. Ultimately, the nearshore must be treated through a fully three-dimensional model. The topics discussed: - Equilibrium properties of beach profiles - Equilibrium beach profile (x^(2/3)) - Equilibrium profile with sloping beach face - Applications of equilibrium beach profiles - Depth of closure - Erosion and accretion predictors