Análise de riscos à degradação ambiental utilizando avaliação multicritério espacial, no município de Boa Vista - PB.

Abstract

The exploitation of the Caatinga biome occurred in a predatory way over the years. Degrading factors like deforestation and fires, in association with the improper use of the soil and unfavorable climatic conditions, have caused biodiversity reduction in the semiarid region of northeastern Brazil, with consequent degradation of its lands. The complexity of the variables involved in natural environments has motivated the scientific community to search for solutions for planning the use and management of their resources, through an integrated approach. The current study aimed to map and analyze the areas with different levels of risk to the environmental degradation process in the hydrographic basin of the Juá dam, which is situated in the municipality of Boa Vista, in the semiarid region of the state of Paraíba. As to the methodology, multi-criteria analysis was performed with support of geotechnologies such remote sensing images (TM/LANDSAT-5 and SRTM) and the free software of geographic information system (GIS), the SPRING system. Relative criteria or factors (soil occupation, soil type, declivity and dwelling) and restrictive (water bodies) were used in the analysis process. Weighted relative importance among criteria was fulfilled by a team of experts in the field of this research by using the Analytic Hierarchy Process (AHP) method. For multiple-criteria aggregation (MCA), the weighted linear combination (WLC) was used which generated the map with spatial distribution of risk levels to the environmental degradation process. Results show that the class of very low risk level is distributed in 10,02% of the total area of the studied basin while the class of low risk level is distributed in 35,57%. The class of medium risk level presents the largest area in the basin occupying 45,07% of its lands. The class of high risk level is distributed in 3.64% of the basin area. The class of very high risk level occupies 4.21% of that area, being distributed mainly in the sectors of bentonite extraction. The north region and part of the southwest region of the basin constitute the areas with the highest risk levels to the environment degradation, while the southeast region includes the areas with the lowest risk levels to this process.