Geotecnologias aplicadas a degradação ambiental na subbacia hidrográfica do Rio Espinharas situado no semiárido paraibano.

Abstract

The Brazilian northeast is part of the semi-arid regions around the world, its biome, Caatinga, is the one with the greatest diversity of fauna and flora, differentiating itself from other seasonally dry tropical forests. It is one of the most populous semi-arid places in the world, home to approximately 27 million people. In this context, the objective of this work was to classify the environmental degradation and vegetation cover of the Espinharas River Sub-Hydrographic Basin in the backlands of Paraíba over a period of 30 years. The study was carried out in the municipalities of the Espinharas River Sub Basin, which covers the area between the states of Paraíba and Rio Grande do Norte and which the Water Resources Plan of the Piancó-Piranhas-Açu River Basin, characterizes the Espinharas River Hydrological Planning Unit. The climatological mean, median and basic statistical precipitation of each municipality were analyzed. Also, a survey of land use was carried out by IBGE's SIDRA Platform, observing the agricultural census and the harvested area. The Qgis software was used to process the images, acquired from the USGS and, subsequently, field observations were made to support the classification and preparation of thematic maps. The images that were used in the project are those from the TM/LANDSAT-5 satellite and the OLI/LANDSAT-8 satellite. The maps were prepared at the Remote Sensing Laboratory at the Federal University of Campina Grande (UFCG). It was found that there is a need to adjust the data relating to climatology, which differ from those provided by the responsible bodies. Crops and livestock reduced significantly, some municipalities stopped producing, due to lack of adequate management and prolonged droughts. The most significant erosion is 0 3 1 t.ha.year-1, which corresponds to 66.934%, high and moderate erosion represents 4.052 and 8.519%, respectively. There was a recovery in vegetation, Exposed Soil reduced from 17.53% to 2.4%, from 1993 to 2022, Sparse Vegetation, from 35.16% to 26.21%, Semi-Dense Vegetation represents the largest vegetation cover, with 54.45%, followed by Dense Vegetation 8.60% in 1993, which reached 15.16% in 2022. Degradation has been gradually decreasing, due to the recovery of vegetation, Severe Degradation was 31.07%, in 1993, which represented 8.24% in 2022, in the same time interval Moderately Severe degradation increased from 53.52% to 59.76%, Moderate increased from 9.93% to 24.91, and Moderate Low 0.97 to 4.91%, which demonstrates the gradual reduction in degradation. In the Espinharas River Basin, it requires adequate management to recover fauna and flora, and reduce degradation, in an accelerated manner.