Zoneamento geoambiental em microbacia hidrográfica do Semiárido Paraibano.

Abstract

A major concern of humanity, to seek improvements in quality of life, has been the rational use of natural resources, recovery and preservation of the environment. In semiarid region of Brazilian northeastern, some features are worth mentioning, as production activities, high population density, soils deteriorate, variations in rainfall and climatic instability. In this context, the aim of this study was to develop a tool geoenvironmental zoning, from the analysis of the suitability of use/occupation of land, based on the roughness coefficient, in a semiarid watershed paraibano, to determine areas with potential uses and environmental fragilities, to encourage rational use, preservation and conservation of natural resources as well as improved quality of life and local development. For this purpose, we developed diagnostic of the physical and, through the factor roughness coefficient, it was possible to identify areas of suitability for use in the watershed. The results were obtained by the proposition geoprocessing methodologies, such as assessment tools for each stage of the work. The area of study was the watershed Riacho Fundo, located in the district of Ribeira in Cabaceiras in the state of Paraíba, which has an area of 3757.9 ha. To study the suitability of land use, it was done an adaptation of the roughness coefficient factor for the region, as well as analysis of physical data to drainage system, climate, soils, slope, topography and land use and occupation. Regarding the use, the vegetation covers 92.8% of the watershed, consisting of shrubs, herbaceous and woody caatinga; still, 0.9% consists of water bodies, 2.4% for areas with agricultural cultivation; 3.2% with the presence of erosion and rock outcrops and 0.7% of the area with the presence of roads and buildings. As for the fitness of use, 82.1% of the watershed is classified with the fitness A, or use simplified, being areas for liable facilities installation or construction of techniques of containment of soil and water, along the low areas where unconsolidated material stemmed from concentrate higher parts of the watershed. It can also be used with annual and perennial crops, livestock breeding, grazing and/or reforestation and wildlife, being cultivated with simple management practices and conservation. Still, 17.9% have fitness D, or use protected with restricted uses, mainly being allowed to use as shelter and protection of wild fauna and flora, or to environment for recreation, or for water storage. These are areas unsuitable for farming, grazing or forestry.