Natural Stability of Beaches Around a Large Bay

Abstract

A numerical wave refraction and longshore sediment transport model was employed to examine the alignment of two long sweeping beaches and a series of headland beaches in an essentially enclosed embayment, Port Phillip Ray, Australia. The model, which is suitable for general application to irregular bathymetry and variable wave conditions, indicated that net sediment transport along these beaches was essentially zero under the prevailing wind-driven wave-energy climate. As the bay is almost fully enclosed, the results suggest that the beaches have obtained an alignment which is in equilibrium with the overall shape of the bay and the local weather conditions. The analysis highlights the importance of beach alignment in a sediment-limited environment and the need to conform with the equilibrium alignment when establishing artificial beaches in this bay and bays of a similar type.