Geoprocessamento aplicado na determinação da fragilidade ambiental da sub-bacia hidrográfica PC5 do Rio Ibirapuitã – RS

Abstract

This paper aims to propose a methodology using geoprocessing tools to measure the environmental fragility of a watershed, this methodology can be used in other study units for the same purpose. The environmental fragility can be defined as the degree of susceptibility where an environment is exposed to some kind of damaging event, taking into account aspects such as natural relief, slope, rainfall, soil, and the human action on the environment. The sub-basin hydrographic PC5 is located in the vestern region of the State of Rio Grande do Sul (Brazil), being one of the hydrographic basins that comprise the Ibicuí Basin hydrographic, covering, in itslarge part the APA of Ibirapuitã. The methodology used in this study was based on empirical analysis of the fragility of natural and anthropogenic environments proposed by Ross in 1994. The weights of each environmental feature were assigned in a participatory manner using the software Vista SAGA. You can evaluate the predominant potential weakness in the watershed is classified as average, prevailing in Neossolos and Planossolos and its largest geological formation of the Serra Geral. But when is attributed to human variable with the map of use and occupation, there is a significant increase in average areas and high fragility, still added a new class of very high fragility. The identification of classes of weakness allowed an analysis of the natural conditions of the environment, along with the human factor, where this weakness varying degrees have been identified, making the methodology efficient.