Erosional patterns induced by coral reefs in the eastern coast of Brazil

Abstract

Beaches are highly dynamic environments that directly respond to changes in wave climate. These changes may influence already existing erosional problems. The general objective of the present study was to describe the wave climate of the coast of Porto Seguro, eastern Brazil, to evaluate how mean and more energetic wave conditions influence local coastal dynamics, inferring possible causes of erosion focuses observed in the area. The Coastal Modeling System SMC-Brasil was used to assess mean and more energetic waves reaching the coast in order to evaluate coastal current patterns. The most frequent wave directions observed were from ESE and SE. The presence of coral reefs adjacent to the coast created zones of low wave energy and focuses of higher wave magnitude along the coast as a result of diffraction. Coral reefs and beachrock outcrops were shown to play an important role in current patterns and greatly influence the erosion focuses observed in the area, which were found to be intensified during austral autumn/winter months.