Análise da variação da linha de costa no litoral do município de Paracuru, Ceará-Brasil

Abstract

The beach, being the transition band between the continent and the ocean, has a dynamic controlled directly by the action of coastal processes such as waves, tides, currents and winds, together these factors provide a balance between the volume of sediment that enters and leaves From the beach system, therefore, coastal erosion is formed when this equilibrium is broken, causing a deficit of sediment on the beach, which directly impacts the retreat of the shoreline. In this context: The municipality of Paracuru, located on the west coast of the state, is located approximately 85 km from the city of Fortaleza. It has presented serious problems due to the advance of erosive processes along its coast in the last decade. Therefore, the objective of this work was to To analyze the spatiotemporal behavior of the shoreline against erosive processes in a part of the coast of Paracuru, aiming at identifying areas susceptible to erosion and also planning the use and occupation of the coast. The methodology consisted of monitoring the behavior of the shoreline through field work using a RTK-type GNSS receiver associated with a topographic survey along 5 perpendicular beach profiles for morphological variation analysis and sediment sampling for variation analysis. textural approach to the action of coastal processes acting in the sector under study that is approximately 2.5 km long. Satellite images from 1977 to 2019 were also used to identify the shoreline by GIS environment, using its Digital Shoreline Analysis System (DSAS) extension, which allows the determination of erosion rates, progradation through statistical analysis. and stability along the monitored stretch. It was observed that the stretch of beach selected as the study area, presents a large process of disordered occupation, resulting in several points where the coastline is delimited by walls, sidewalks, among other constructions. The results showed that the whole monitored stretch presents negative rates of variation of the shoreline between the analyzed year interval. Withdrawal rates of up to 2.16 m / year were observed over the 42 years analyzed. Evidencing an erosive tendency in the region. Therefore, continuous monitoring of the Paracuru beach shoreline is required and a reordering of occupation that focuses on the post-beach zone.