THE LAGOONS OF ALAGOAS IN THE CAATINGA BIOME: DETECTION, ANALYSIS AND TEMPORAL MAPPING WITHIN THE CONTEXT OF CLIMATE CHANGE

Resumo

This research aims to map and evaluate dynamics of surface water bodies in Caatinga biome in Alagoas in Northeast Brazil, from 1987 to 2017, using remote sensing data. Hydrography was considered an important element in history, culture, economy and landscape in the State of Alagoas, whose toponymy originates from the numerous lagoons that are distributed throughout the territory. Using temporal satellite images and own methodology to process these images, existence of three groups of polygons that mapped the lagoons and dams of that period were detect. Although the balance had been positive, in 1987 2,003 polygons were detected and in 2017, 3,133, it is highlighted the disappearance of 1,349 ponds/weirs, most of them smaller than 1 hectare. Taking into account the serious impact on the weir system in the sertão, tracks were sought to elucidate its causes. For this, a field validation was defined for seven water bodies selected in five municipalities in the region, showing heterogeneity of reasons for the decreases in the surface water, or even their disappearances, including climate change. As a result, a complex social and environmental picture that requires immediate action from the government and society to mitigate the impacts of climate change was revealed.