Análise multivariada de dados hidrogeoquímicos para a identificação de unidades aquíferas

Abstract

For an adequate management of groundwater, it is important to have a broad hydrogeochemical knowledge of the region, which is commonly hampered by the absence of constructive and lithological data from the wells present in the area. Multivariate analysis of hierarchical clustering has been used in the treatment of hydrochemical data. The groupings are carried out according to the dissimilarity distances between the concentrations obtained for each analysis parameter at each sampled point. From the analysis by hierarchical groups, it is possible to separate the analyzed waters by aquifer units to which they are related. The analysis by hierarchical clustering was applied to the hydrogeochemical data obtained from the sampling of groundwater in 10 water points located in the APA Karst region of Lagoa Santa and surroundings. From the generated dendrogram, which considers the Ward Method and the Euclidean distance, 03 aquifer units were identified: waters related to the limestones of the Sete Lagoas Formation, waters related to the metapelites of the Serra de Santa Helena Formation and waters related to the rocks of the granitegneiss basement. Thus, the applicability of the method to determine aquifer units was proved, minimizing the problem of lack of data from the wells in the hydrogeochemical characterization of an area.