Characterization of the Environmental Vulnerability in the Rio Preto River Basin, Maranhão – Brazil

Abstract

Environmental vulnerability is defined as any susceptibility of the environment to a potential impact caused by any anthropic use. The basin located in the northeast region of Maranhão state occupies an area of 5,235.63 square kilometers. The study development of the environmental vulnerability of this basin is important because it serves as a subsidy to environmental planning aiming at the sustainability of water resources. The paper objective was to characterize the environmental vulnerability of the Rio Preto basin, considering soil integration, slope, geological structure, and land use and cover based on its stability in relation to morphogenesis and pedogenesis aiming to contribute to the erosion risk mitigation. For this, geoprocessing techniques were used, which allowed the establishment of three types of environmental units: stable environments, where pedogenesis predominates; intergrades mean, in which there is a balance between pedogenesis and morphogenesis; and the highly unstable, where morphogenesis predominates, to determine the intensity and distribution of vulnerability in the basin. It was found that 33.59% of the area is vulnerable, 35.61% are moderately vulnerable and 30.80% are represented by stable areas. It was found that the use of land for soybean and eucalyptus cultivation in the south of the basin increased the degree of environmental vulnerability, as it intensifies erosive action in soils.