Avaliação da relação entre variáveis físicas e de qualidade das águas em reservatórios de usinas hidrelétricas de Minas Gerais para gestão das águas no estado

Abstract

Water is a natural and essential resource formaintenance of life and multiple uses. The energy matrix inBrazil is predominantly hydroelectric, which prevails in Minas Gerais. Water quality monitoring, which is expensive and labor intensive, generates a large amount of data. Morphometric data are considered relevantin the evaluation of physical-chemical and biological events and forthe understanding of reservoir dynamics, not requiringconstant monitoringsuch as for water quality. The present work was based on water quality and reservoir morphometry data, available in the Reservoirs Water Quality Information System (Siságua) of the CompanhiaEnergética de Minas Gerais (Cemig), assessing29 water bodies. The applied statistical procedures were Cluster Analysis to identify reservoir types and Principal Component Analysis to select the most expressive variables in the sample set. The results showed that the most significant water quality parameters were turbidity, conductivity, pH, transparency, BOD and total dissolved solids, and the morphometric parameters were area, perimeter, volume, residence time, drainage area and flow rate. There was coincidencein part ofthe groupings for the two analyzes, and the water quality presented a spatial relationship. Thiswork contributesto the management of reservoirs in the State since it systematized, organizedand ordereddata, also establishing relationships between water quality and morphometric information.