Erosão fluvial: um risco eminente para a cidade de Parintins - AM

Abstract

Fluvial Erosion, commonly known as “fallen lands”, is an Amazonian phenomenon responsible for the main changes in landscapes. It is characterized by the unraveling of river banks, caused by erosive agents. In Parintins, this drastically affects the unprotected riverbank, and the construction of the retaining wall, compromising the stability of its extension and its main function, to contain the erosion processes in front of the city. When navigating the Amazon River, you can see in the lowland lands long collapsed strips - the fallen lands -, because it is a fragile terrain susceptible to contact with the water of the river. The occurrence is also observed in areas of terra firme on the banks, where erosion is slower, but constant. In this way, the research was carried out in a stretch of the front of the city, which comprises the vicinity of the slaughterhouse Frigorífico Osório Melo (East) and the retaining wall (West), where the survey was carried out by land, making the necessary observations to detect cracks in the streets and thus determine the degree of fragility. The research aims to understand river erosion, its influence and occurrence as an imminent risk for the city of Parintins. The methodological procedures consisted of on-site visits to observe and identify the areas most affected by the action of river erosion. Making photographic records, notes in a field notebook, measurements with tape measures and georeferencing these areas with the use of GPs. From the accomplishment of the research, it is concluded that the action of erosion in the vicinity of the Slaughterhouse, is given by the combination of several erosive factors, of hydrographic and climatological order, with emphasis on anthropic action. Fluvial erosion in the retaining wall causes undermining by the impact of hydraulic pressure, being greatly influenced by the infiltration power of the impacted soil, where water penetrates the pores between the sediment particles increasing the volume of its mass, which causes the imbalance of the affected place, consequently causing the detachment of parts of the construction. However, this research shows that this phenomenon needs more research to give answers to existing questions and look for solutions. As well as drawing the attention of authorities to the development of public policies and mitigating actions against the effects of river erosion in front of the city of Parintins. Thinking of a better way to protect her.