Análise da vulnerabilidade dos sistemas ambientais da bacia hidrográfica do rio São Nicolau- semiárido Piauiense

Abstract

The increasingly intense exploitation of natural resources is reflected in the levels of environmental and social vulnerability of the various environmental systems present in the semiarid Piauí domain. The objective of the research is to analyze the areas of environmental vulnerability of the São Nicolau River Basin (SNRB) based on the appreciation of physical and socioeconomic environmental systems. And, as specific, perform the physical-environmental characterization based on the collection of pre-existing information; to classify the environmental systems of the São Nicolau river basin considering the capacity of support based on the principles of the ecodynamics of Tricart (1977) to elaborate an Environmental State Index of the same (IEA); to evaluate the socioeconomic context and the dynamic process of the forms of use and occupation to elaborate the Basin Socioeconomic Environment Index (IASB); to verify, based on the indices, the environmental vulnerability of the basin and the degree in each of the present environmental systems; to carry out the propositional zoning of management and conservation of the environmental systems in order to subsidize the planning and the decision making in the management of the basin. The SNRB is located in the central-north region of the state of Piauí occupying an area of approximately 5,389.8 km2 that covers part of the municipalities of Assunção do Piauí, São Miguel do Tapuio, Pimenteiras, Aroazes, Santa Cruz dos Milagres and São João da Serra. It is a research with methodological approach of qualitative and quantitative nature. The basin was compartmentalized into environmental systems. Then, indexes were constructed for the environmental and socioeconomic status through multithematic indicators that made it possible to measure the levels of vulnerability of the SNRB. In addition, field analyzes and the use of GIS were performed. Part of the basin area is comprised of high vulnerability levels, above all the region comprising the high course and the fluvial plain in the low course, totaling about 1,475.47 km2 of extension with a high level of vulnerability. However, the SNRB still displays much of its area with low levels of vulnerability. With this, the depreciation of activities would not be the solution. The investment in road infrastructure, planning and management in the area, in order to exploit resources based on the reality of the unit, considering the levels and environmental vulnerability of the basin, will certainly be able to build a development model based on the sustainable use of resources.