Evolução da linha de costa de Salinópolis, Nordeste do Pará, Brasil

The average rates of change of the shoreline are a good index for determining evolutionary trends in any stretch of the coast. In Salinopolis city, although this trend beis the deposition of sediments on the shoreline, in places where human occupation is consolidating, the coastal erosion has caused significant impacts (decrease of tents, partial loss of houses and breaking the access roads to the beaches). Thus, it was performed with the Digital Shoreline Analysis System , the multitemporal evaluation (25 years) of shoreline change in the urban stretch of Salinopolis from the Landsat satellite images analysis, limiting the study area into three sectors (Western: Corvina and Macarico beaches, Center: Farol Velho beach and Eastern: Atalaia beach). In the period of 07/22/1988 to 08/28/2013, the linear average retreat obtained for the entire study area was -42.25 m, while the linear average increase was 190.26 m, indicating a progradational trend of the coast. The highest rates of change occurred between the 1988-2001 period, with 18.24 m/year in the Western Sector, 0.06 m/year in the Center Sector and 5.08 m/year in the Eastern Sector. The eroding areas are isolated and occur at the edges of the Corvina and Macarico, and Farol Velho and Atalaia beaches, more exposed locations to the ocean and where urbanization is consolidated in a disorderly manner. The depositional trend of sediment in the shoreline predominates since 1988, exclusively on the margins of each beach, derived from high sediment load brought by estuaries that cut the area.