Caracterização e monitoramento de voçoroca associada a técnicas de controle através do método de estaqueamento

Abstract

Erosion consists in a natural geological process that is part of the terrestrial surface dynamics. However, human actions such as deforestation, agricultural activities without the adoption of conservationist techniques and excessive grazing, are the main responsible for the appearance of erosive features in rural areas. Such actions, associated with certain geological-geotechnical and environmental characteristics, can develop small and large erosive processes. Gullies are the most evolved and complex stage of linear erosion. For this reason, the recovery of areas degraded by these erosive features is, in general, difficult and expensive. Currently, there are several erosion control techniques, which can be adopted in different contexts, however, it is common, in rural areas such as the study sub-basin, to find these techniques associated with erosive processes, indicating misapplication. In this scenario, this work aimed to characterize and monitor by the staking method the evolution of the erosive processes of a sub-basin, where there are erosion control techniques. It was expected to identify if the erosive features are active, the conditions for their development and the reason for the failure of erosion control techniques. To develop this study, several materials were gathered, such as topographic map, satellite images, geological, pedological and geomorphological maps, as well as bibliographic materials. In addition, fieldworks were carried out to characterize and monitor erosive features, identify and evaluate erosion control techniques, and to verify and identify environmental aspects previously evaluated in office works. It was found in the study area an active gully erosion, continuous to the drainage channel. Analyzing the satellite images of the different years, it was verified a significant increase in the gully dimensions, while the staking method identified that the evolution of the gully is due to the destabilization of its walls. The geological-geotechnical and environmental characteristics of the study area, mainly the land use, explain the development of the gully erosion, at the same time the erosion control techniques proved to be inefficient, either by arbitrary use, as is the case of the brush barrier technique, or due to execution failures, as it was verified in the case of terracing.