Karst depressions’ hydric behavior of the Lagoa Santa region, MG

The karst depressions are configured as important dissolution features present mainly in limestone regions. From the typical karst hydrogeology and geomorphology´s perspective the present study aims to investigate carried out in the karst depressions located on the politic-carbonate rocks of the Bambuí Group, located in the vicinity of Lagoa Santa Karst Environmental Protection Area (APA) – (MG). The investigations had as main objective the understanding of the behavior and water performance of the 393 karst depressions detected from Digital Elevation Model (MDE) derived from an ALOS PALSAR satellite image. The stages consisted basically of geoprocessing via GIS, photo observation through images from Google Earth Pro and supervised classification in multispectral images of the Landsat satellites recorded in four different hydrological periods (year with normal rainfall index and year atypically dry). The Kappa coefficient and Global Accuracy indicated that the supervised classifications performed had excellent results. The multivariate statistical analysis showed that the presence of lagoons in the interior of the karst depressions after drought period in normal hydrological year or in year of exceptional water stress is related to the morphology and morphostructural, that is, to the major depressions with great depths, high indices of stretching axes and large areas of limestone massifs in their interiors are those most favorable to having water in their interiors.