Formation of Stable Sandy Beaches and Beach Erosion Control : A Methodology for Beach Erosion Control Using Headlands and Its Applications

Abstract

Many attempts have been made to control beach erosion throughout the world, but in the long term none have succeeded in stabilizing sandy beaches that are being eroded. Almost all the common countermeasures are of little use for stabilization as they cause beach profiles gradually to become steep. Some beautiful natural sandy beaches exist that are stable and in equilibrium for longshore sediment transport. The equation for a stable sandy beach is derived from the set of equations of continuity for beach change and longshore sediment transport under unsteady and nonuniform conditions, so that theoretical shoreline configurations can be obtained for both static and dynamic stable sandy beaches. The theoretical shoreline configurations of dynamic stable sandy beaches compare satisfactorily with those of actual sandy beaches and provide a theoretical background for the formation and existence of natural stable sandy beaches. A methodology for beach erosion control is proposed that is based on this theoretical background by which a series of stable beaches are formed from eroding sandy beaches. This method also is applied in relation to the large scale coastal behavior of sandy beaches. Its application under actual erosion situations has resulted in stabilization based on the establishment of well-formed stable sandy beaches. A brief description for further improvement of this methodology is also given.