Configuração da rede de drenagem e modelado do relevo: conformação da paisagem na zona de transição da bacia do Paraná na depressão central do Rio Grande do Sul

Abstract

This work presents the relief modeling as a cause and consequence of soil erosion. It is in the space, which man has always depended on to live, that the biotics, non-biotics and social-economic components interaction occurs. The relationship between men and environment was, and it still is followed by the progresses that provide nature s understanding and contribute for softening the negative impact above it. The facts that allow the physical landscape perception make it possible to conclude that the alterations caused by the interferences in the environment can lead towards a prediction of the actions on the set. Therefore, human intervention must be planned considering the potentiality and fragility of each natural environment. Because of that, this work emphasizes that the shapes, or set of relief shapes are a part of the landscape composition. It considers the relief modeling as a result of geological, climatic, hydrological and soil characteristics, reflected in the drainage density and in the bottom of the valley carving degree. Takes into consideration studying the relief, meaning that the relationship between drainage and soil erosion allows qualifying the drainage configuration as a result of the soil erosion. It also suggests that if we consider the slope s morphogenesis, there is a cause-effect relation in which circumstances such as the characteristics of physical-mechanical properties at its natural fragility degree influence. Searches to identify the cause through soil erosion and deposition, which are considered as modeling s agents, and the effect through drainage and slope s morphogenesis. It concerns to the necessity of studies connected with soils and its properties, facing the relevant function that they take in Geomorphology. This work used the Southwestern community of São Pedro do Sul-RS as a study area, and it presents as litological support the Sedimentary Paraná Basin. It is structured in 6 itens in which it was possible to establish that the modeling of accumulation refers to the river sediments deposition, originated from processes of river deposition. The dissection areas characterize geomorphologic command features from the Periferical Depression of Rio Grande do Sul. It was also possible to realize that there is a low relief in the area with predominance of Sanga do Cabral formation as a result of the high level of natural fragility. In this area there is a predominance of concave profile slopes. Another observation is the higher number of concave-convex forms at the areas related to Santa Maria and Caturrita formation. The relief energy has a high level of fragility to these areas in the search for balance, led by the river dynamic.