Morphodynamic classification, variations and coastal processes of Paiva Beach, Pe, Brazil

Abstract

The coastal zone related to the continental and oceanic portions, considered as dynamic and complex, undergoes changes at different time scales. The morphodynamic classifications of beaches are essential for monitoring sedimentary cycles, identifying temporal processes of stability, accretion and erosion. The objectives of this study are to evaluate the morphodynamic classification and the identification of some coastal processes considering a spatial analysis (2010, 2011 and 2012) at Paiva beach, located at Cabo de Santo Agostinho, Recife metropolitan region, Pernambuco state, Brazil. For this, we used three-dimensional information from the digital terrain model obtained by Global Navigation Satellite Systems, as well as hydrodynamic data (wave climate). The results showed the identification of berms, cusps and rip channels besides three morphodynamic stages during different dates, being them: transverse bar and rip; rhythmic bar and low tide terrace. The waves have E, ESE and SE direction with significant wave height ranging from 1.61 to 3.39 m with 9.3 s of average wave period. The temporal profiles showed significant variations, demonstrating accretion and erosion processes, which varied around 1 m (vertically) in the spreading zone. The sedimentary balance evaluation showed accretion in the spring and summer periods and erosion from autumn to winter. The mapped features proved to be effective for the proposed morphodynamic classification, generating important subsidies for coastal zone monitoring.