MACRO-MESO TIDAL BEACH MORPHODYNAMICS - AN OVERVIEW

Macro- and meso-tidal beaches are ubiquitous global coastal features about which comparatively little is known compared to their micro-tidal counterparts. A review of the literature reveals a considerable range in macro-tidal beach morphology and dynamics but with little perceived order in the range. This review together with recent morphological data from macro-tidal beaches on the central Queensland coast are combined to provide an overview, and to identify three types of macro-tidal beaches. Two are true beaches. Higher waves, and particularly swell produces moderate gradient (1-3-degrees), concave, planar beaches dominated by incident, though infragravity wave energy. Moderate waves and sea conditions tend to produce lower gradient (0.5-degrees), multi-bar (ridge and runnel) topography also attributable to infragavity standing waves. As wave energy drops still further a third type results with a high tide beach fronting tide-dominated tidal flats. This latter is not a true beach but rather a transition from beach to tidal flat.