Natural and anthropogenic processes on the recreational activities in urban Amazon beaches

Abstract

The Amazon coastal zone is characterized by high levels of hydrodynamic energy influenced by both marine and continental processes. This region commands a great deal of interest from economic, social, and environmental viewpoints, and is affected by the interaction of a number of natural and anthropogenic processes, which have a direct influence on the conditions found on local beaches. The present study analyzed the quality of the beaches of the Amazonian city of São Luís, considering natural (climatic, morphodynamic, and hydrological processes) and social (occupation of the land and types of services and infrastructure) conditions. A system of beach classification was also used to assess coastal quality regarding both natural and socioeconomic characteristics. The results of the study indicate that the local beaches are being occupied increasingly by urban development, which is affecting the equilibrium of depositional systems, primarily through the occupation of dunes and cliffs. In addition, the local water quality has been affected by the lack of an adequate public sanitation system and the presence of numerous illegal sewers on the beaches, which contribute to the elevation of thermotolerant coliform concentrations above the limit permitted under Brazilian legislation. These features contributed to the classification of the sites as regular quality beaches, according to the indices applied in this study. The lack of local urban planning has caused serious social and environmental problems and effective management plans for this sector of the Amazon coast are urgently needed.