EMERGING ENVIRONMENTAL FRAGILITY OF THE SOBRADO RIVER WATERSHED, SOUTHEAST OF TOCANTINS

Abstract

The modifications produced by human interventions in natural landscapes can generate environmental impacts at different levels. When considering the watershed as an environmental system where nature and society interact, it becomes necessary to understand how natural and anthropic factors interfere with the levels of environmental fragility. The objective of this work was to identify the environmental fragility of the watershed of the Sobrado river, located in the southeast of the state of Tocantins, characterized by the presence of a karstic landscape. Therefore, the methodology consisted of the elaboration of the rainfall map, slope map, and map on the types of soils. The land use and the land cover map were prepared from the interpretation and digital processing of Landsat 8/OLI images, classification supervised by the battacharya method, in the SPRING software. The information was superimposed to obtain the emerging environmental fragility. The results pointed to the identification of the lower class predominant in the basin, including the forms of use and areas of native vegetation cover. The middle class occupied the second position, influenced by the combination of physical and anthropic factors, including soil types, pastures, and native vegetation cover. In addition, the upper class occupies a small area, including the location of rocky outcrops and areas with steeper slopes. It can also be concluded that the area with the highest concentration of caves is under the influence of the middle class with environmental fragility, raising the need for the elaboration of guidelines for environmental planning and adequate land use.