Estuarine Beach Morphology in Microtidal Middle Harbour, Sydney

Abstract

Microtidal Middle Harbour, Sydney, contains a range of estuarine beach morphologies from steep reflective beachfaces to wide low‐tide terraces. The most exposed beaches are morphologically similar to lowest‐energy open‐ocean beaches; however, the remainder of the profiles cannot be adequately explained by established beach morphodynamic models. Estuarine beach morphology in Middle Harbour appears to be primarily influenced by storm events. Deep‐water ocean waves rework profiles in the lower part of estuary. For beaches protected from these waves, tidal fluctuations are the main determinant of beach profile. Locally‐generated wind waves are only a significant energy contributor where the fetch is large enough; however, this only occurs on two beaches where low‐tide terraces are formed.