Short to medium-term morphodynamic behavior of the beaches of the municipality of Goiana, Pernambuco, Brazil

Sandy beaches undergo rapid morphological variations in response to changes in coastal processes and climate conditions. It is known that many of them exhibit dynamics related to geological control exerted by nearby geological outcrops or on the very coastline. The coastline of the municipality of Goiana, Pernambuco, Brazil, is characterized by a sandy beach strip along the Ponta de Pedras mega salient, which forms in the shadow zone of a large adjacent offshore reef line. The morphosedimentary dynamics of the region are still poorly understood, and the studied area has been undergoing a rapid urbanization process, as well as showing erosive conditions in certain areas. To understand the short to medium-term morphological responses of the beach ridge, this study aimed to survey the topographic and sedimentological conditions of the beaches in the area, with the objective of identifying their dynamics between July 2017 and May 2019. It was observed that the central beach profiles of the study area have greater stability in all subsectors of the beach profiles, from the backshore to the upper foreshore, favored by the protection of the reefs. At the same time, the coastal circulation generated, influenced by these obstacles, favors the formation of multiple sandbars parallel and transverse to the beach, with poorly selected sediments due to the presence of carbonate gravels. The profiles farther from the center of the mega salient are subject to greater mobility within the sediment package due to complex interactions with openings between the reefs, tide variations, and locally generated circulation cells. The observed erosive conditions are associated with the influence of the Itapessoca River mouth to the south, and the impermeabilization and fixation of the backshore sector by urbanization over the beach stretch.