Coastal hydroforms and hydromorphologies vs wave and beach parameters

The wave and structures/land interactions are rather complex and thus of difficult characterization. This is not only due to the existence of a dynamic action of non-linear characteristics over different time scales, but also to the great difficulty to obtain long data series. Coastal hydroforms and hydromorphologies are very frequent in sandy beach coasts and, in general, they are very dynamic, particularly with the variation on wave climate, beach slope and sediment dimension. In this context, the main objective of this paper is to present results of the correlation between hydroforms and hydromorphologies and wave parameters. The hydroforms and hydromorphologies were identified based on image interpretation that consists on a visual identification onscreen in a GIS environment of eight aerial photographs' surveys. Beach cusps, megacusps and gigacusps length (λ), width (ω), as well as minirip currents and rip currents spacing (ε), were measured. The results were correlated with wave parameters offshore and at breaking zone, such as: significant wave height (H _s), wave breaking height (H _b), wave period (T), wave direction (θ), wave length (L), kinetic energy (E _k), wave power (P), among others. It was also considered the tide level. This analysis shows that, in general, with increasing wave energy, coastal hydroforms and hydromorphologies increase in size, as well as rip current spacing. It was also observed that the smaller features and patterns in size and spacing are influenced by wave conditions that occur during small periods of time. On the other hand the larger features and patterns which remain for a longer period of time, are formed by wave conditions that act for longer periods of time.