Spatial-Temporal Mapping Of The Problems Resulting From Flow Restriction In The Lower Course Of The São Francisco River

Abstract

The main purpose of this study is to analyze the impacts resulting from the flow restriction and its effects on the fluvial dynamics of the lower course of the São Francisco River, specifically in the section corresponding to the municipality of Traipu - AL. In this sense, the work sought to identify the evolution and genesis of emerged river bars in the period from 2013 to 2019. For that, different images from the Landsat 8 satellite and the flow data available on the HidroWeb Portal, of the National Information System on Water Resources (SNIRH). Therefore, the analyzes using orbital images indicated an increase in the surface area of ​​the existing bars and the emergence of new features, when compared to the images related to the year 2013. Considering the behavior of the outflow of the reservoir, which corresponded in 2019 at 826 m3/s, in the interval of approximately six years, between the period from 2013 to 2019, the surface area of ​​the emerged bars increased by 62.86%, that is, they had an increase of 2,200 km2, occupying an extension of 5,700 km2. In general, the results showed that the use of geoprocessing oriented to landscape analysis was effective to achieve the proposed objectives. From the analysis of satellite images, it was found that in the period observed, the dynamics of genesis and evolution of the bars on the banks of the municipality of Traipú - AL have a direct relationship with the variation of the flow.