Análise dos padrões fluviométricos da Bacia do Rio Madeira - Brasil

Abstract

This study shows the results of a simplify analysis about the variability of water levels on the watershed of the Madeira River on the Brazilian area. This work between the years of 1980 and 2010 and, mainly, in years that revealed extremes hydro-climatic conditions. It’s centered on the observations of hydrologic patterns, through temporal series of fluviometric measures, in physiographic conditions and on official documents about Flood and Drought Disasters. Discusses the effects of extreme events on the communities, in order to identify patterns from a safe and reliable analysis, whose results may be used by those same communities.Madeira River is the main tributary of Amazon River. Its watershed covers an area of almost 1,4 million km2 which represents 23% of all Amazon Watershed. This area involves portions of three South American countries: Bolivia, Brazil e Peru. In Brazil, it’s comprehended the states of Amazonas, Rondônia e Mato Grosso. Were used data from Hydrological stations of National Agency of Waters – ANA National and from the Observatory of Environmental Hydrology, Geochemistry and Geodynamic of Amazon Basin - ORE / HYBAM. The observations about the hydrological variability were compared with damage evaluation reports and ordinances available on Nation Guard database. The results shown that the greatest events of flood and ebb allowed make considerations about the hydrological behavior of the basin considering those events. The major part of stations shown flood season on months March, April and May, and ebb season in the months of August, September and October.The quotagrams revealed one single peak of flood and ebb on the studied stations. According to chart with normalized indices, the critical events of flood and ebb do not behave on the same way through the Madeira River, which can be explained by variation of altitudes of the terraces and slopes of those locations. In this sense, there is a great influence of local physiographic aspects, mainly related to the existence of the lowland areas, because the residence time of water in the system cools downstream propagation superficial. Com flow based on the analysis of official documents, the effects of events extremes are more significant in the municipalities of Amazonas state than in Rondônia state, with the caveat that some periods where it assesses that there are some gaps regarding the care of civil defense in these municipalities and / or supply disruption in database records disaster. In this study, it was understood the complexity of investigating the causes and consequences of extreme events in the Amazon, the need to analyze various aspects of a reality too complex and involves the treatment of hydrologic, physiographic and social data, which are mostly secondary sources and require a tedious validation work to obtain results consistent and truthful.