Estimativa da recarga potencial de aquíferos na bacia hidrográfica do Rio Bicudo-MG

Abstract

Water resources have been increasingly impacted due to the growing demand for their use associated with environmental degradation. Thanks to the importance of water resources for economic, environmental and social activities and processes, it is increasingly essential to study, map and protect areas that are related to the provision of this resource. In this context, mapping the process of aquifer recharge potential consists of an important tool for water managers, in order to direct public policies that prioritize the conservation of this natural resource. This study proposes the application of a spatially explicit model to determine and evaluate the aquifer recharge potential, on a catchment scale, which iscompatible with the Bicudo river basin - MG, Brazil. The model was based on the water balance method and the variables used were compiled from institutional sources and implemented in a Geographic Information System. To improve the model in relation to the soil factor and the dynamics of land use, the Conservation Use Potential (PUC) method was coupled to the model. In addition, the inclusion of a geological factor was proposed, which until this study was not considered in the model. Undisturbed soil samples were collected for laboratory analysis of hydraulic conductivity, with the intention of improving the model and bringing it as close as possible to field reality. As a form of mathematical validation of the model, the results obtained were compared, in average terms, with homologous values estimated by independent methods, namely: the analysis of the recession curve in hydrograms, separation of baseflow by automatic and manual methods, and by the RORA method, which are available on the United States Geological Survey (USGS). The aquifer recharge potential in the Bicudo River basin was 86.66 mm/year, demonstrating a low recharge potential in the area. Through the mathematical validation of the model, it was observed that the average recharge value obtained in the model is within the expected recharge range for the area, ranging from approximately 70 mm/year to 99 mm/year. After the validation step, it was possible to consider that the model realistically represented the aquifer recharge potential in the basin and therefore, it can be used to support the development of plans, projects, and programs to help adopt appropriate practices to conserve groundwater resources in the Bicudo River basin.