ANÁLISE MULTITEMPORAL DA VARIAÇÃO DA LINHA DE COSTA EM PRAIAS ESTUARINAS DO NORDESTE DO PARÁ

Multitemporal analysis of variations in the coastlines of stuarine macrotidal beaches in the Eastern Amazon, Brazil

Abstract

The analysis of variations in the coastlines of beaches through multitemporal images allows the identification of erosive and accretionary processes, on an evolutionary scale. The objective of this work was to evaluate the changes in the coastline of beaches of an important tourist city of the Amazonian coast (Marapanim), between 1988 and 2016, through images of the Landsat satellite. Based on the digitization of the coastlines of the beaches of Santa Maria, Marudá and Crispim, in the reference years and using the Digital Shoreline Analysis (DSAS) extension in ArcGis software, it was possible to perform statistical calculations of spatial amplitude and annual rate of change positioning of the coastline. The results indicated that the beach of Santa Maria is in a state of equilibrium to sediment the increment, presenting variations from 3.89 to -1.23 m/year along the coastline. The beaches of Marudá and Crispim are in the predominant process of coastal accretion, presenting linearly variations from 8.87 to -1.61 m/year, 40.91 to -9.82 m/year; respectively. However, climatic, physical and anthropogenic impacts may have been responsible for decreasing the accretionary rate of the coastline in certain periods (1994-2008), in distinct sectors of the beaches.