Avaliação espaço-temporal da cobertura e os impactos do uso da terra na Bacia Hidrográfica do Rio Pojuca-Bahia-Brasil.

Abstract

Watersheds are important natural areas for territorial management. The Pojuca River Watershed (BHRP), located in the set of watersheds in the North Recôncavo region, is considered of great relevance, enabling economic activity and other fundamental activities for society. The objective of the research was to analyze the dynamics of land cover and use during the period from 1985 to 2020, in a period of 5 years, and the possible impacts on water resources. For this, the basis of the applied methodology is related to the acquisition of statistical data on the coverage and land use of MapBiomas through remote sensing techniques, and for the analysis of the Water Resource, the delimitation of the APPs of the rivers and analysis of the flow were pertinent average of fluviometric stations and vulnerability to water erosion. In order to characterize and understand the analyzed area, analysis of demographic and socioeconomic data was carried out, as well as the dynamics of land cover classes and land use in each municipality, comparing the initial year (1985) and the final year (2020) of the series temporal. In this 35-year space-time evaluation (1985-2020), the advance of the urban area, forestry and pasture classes, which are currently the greatest threat to the integrity of the BHRP's natural resources, was observed. Natural cover classes suffered a reduction such as swamps (-24.2%) and forest formations (-6.9%), in addition to other natural covers such as beach/dune areas (-78.9%) and bodies of water. water (-58.33%). The evolution of the land cover and use classes in the 22 municipalities of the BHRP and the spatial dynamics in each one can be seen. use of land as in Aramari-BA, and also by urbanized areas as in the case of Feira de Santana-BA. Regarding the analyzed Permanent Preservation Areas, comparing the initial year (1985) with the end (2020) of the historical series, there was an advance in the classes destined to land use, with emphasis on forestry (100%), pasture (2%) and urbanized area (1003%). The spatiotemporal evaluation based on the use of classifications on satellite images made available by the 6.0 collection of the MapBiomas project, counts as a considerable warning against the threats that the uses of space represent on the available natural resources.