Retreat Analysis on Cliffs in the State of Rio Grande do Norte, Brazil

On the Coast of the State of Rio Grande do Norte (RN), Northeastern Brazil, coastal erosion generates several problems, especially in the county of Baía Formosa, Tibau do Sul and Parnamirim on the eastern coast of the State and in the county of Touros and Porto do Mangue on the septentrional coast of the State, where the tourist movement and the intense real estate speculation cause several environmental conflicts. Geoprocessing techniques were utilized through Digital Image Processing and Geographic Information System in the multitemporal analysis through the DSAS (Digital Shoreline Analysis System) tool in a scale of 3 decades, using images of remote sensors of spatial resolution of 30 meters and 5 meters to identify the areas that had erosive retreat of cliffs in the coast of the State of Rio Grande do Norte, measuring the retreat and the characterization of these environments. Five areas with erosive retreats were highlighted in the cliffs, in the counties of Areia Branca with the highest identified retreat that reached 101.1 meters and in Touros with the lowest retreat identified in the coast of the Rio Grande do Norte, reaching 18.76 meters. The other three counties, Parnamirim, which presented erosive retreat on the cliff of 34.44 meters, Tibau do Sul presenting 68.32 meters of retreat and, finally, Baía Formosa with 27.44 meters of erosive retreat on the edge of its cliffs. These erosions put at risk areas of heavy urban occupation, diverse infrastructures, and access roads. This analysis identified the areas that are still in the continuous process of coastal and/or pluvial erosion as the areas in which a balance in the dynamics was identified, remaining stable and such information serves as a subsidy for coastal management in these coastal environments of the Rio Grande do Norte coast and for the population that lives there.