Faixas de proteção à erosão costeira no delta do Rio São Francisco

• Autor(a) principal: Correia, Iaggo Oliveira
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: https://ri.ufs.br/jspui/handle/riufs/14234
• topic: Geociência; Vazão fluvial; Sensoriamento remoto; Deltas; Costa- proteção; River discharge; Satellite images; Rates of change; Linear regression; CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS

Coastal erosion in the São Francisco river delta, intensified by the construction of dams along its course, contributed to the destruction of the village of Cabeço, in the State of Sergipe. To minimize or avoid similar damage in the future, it is recommended to implement delimitations as far as it is safe to occupy in a given time, called setback lines. This work aimed to determine setback lines for the São Francisco river Delta. River flow records and images from Landsat-5 and 8 satellites from 1986 to 2017 were used. Linear regression quantified the rates of variation later classified into shoreline behaviors. The most erosive values were used to delimit safety widths for coastal erosion. A validation of the efficiency of the numerical method, used to determine setback lines, was carried out from 1986 to 2017. The setback lines were projected from 2017 to 2037 associated with the criterion in which the setback lines projected by the numerical method located on conservation units or ecosystems would be drawn back to the internal limits of the units. From 1986 to 2017, the average river flow was reduced by 24%, not accentuating the values of the most erosive rates, but contributing to the 32% increase in stretches in erosion along the coastline. The most erosive values of the Alagoas (-55.23 ± 10.06 m/year) and Sergipe (-153.13 ± 0.11 m/year) sides of the delta showed different intensities due to the different coastal dynamics. The efficiency of the numerical method for delimiting safety widths against coastal erosion was validated, and the need to use the setback lines retreat criterion based on local characteristics was exposed. Therefore, the setback lines for 2037 used an numerical method (width of 3,062 m on the Sergipe side) and the criterion of retreat to the internal limit of the Piaçabuçu APA (Alagoas side). This model can minimize or avoid socioeconomic risks to coastal erosion and to encouraging environmental sustainability.