Potencial hídrico subterrâneo do Sinclinal Santa Rita - Província Mineral do Quadrilátero Ferrífero, Minas Gerais, Brasil

Abstract

The Santa Rita Syncline is situated in the eastern sector of the Mineral Province of the Quadrilátero Ferrífero, Minas Gerais, Brazil. This geological structure is of significant economic importance, as it hosts major iron ore deposits of the Cauê Formation. It is equally noteworthy for its hydrogeological potential, characterized by high recharge rates and excellent productivity of tubular wells. Due to these features, the syncline is subject to intense groundwater extraction. The quantity of groundwater reserves was previously unknown. In this context, this study aims to estimate the renewable and permanent groundwater reserves and, more importantly, to evaluate the overall water potential of the Santa Rita Syncline Aquifer System. The research involved the identification of aquifer and non-aquifer units within the syncline, the definition of its hydrogeological boundaries, the determination of the hydrodynamic parameters of its aquifers, and the analysis of groundwater flow. Two distinct aquifer systems were identified: the Minas Aquifer System, consisting of the Fissured Quartzite, Cauê, and Gandarela formations; and the Estrada Real Aquifer System, comprising the Sabará and Itacolomi formations. Non-aquifer units within the syncline include the Batatal and Piracicaba aquitards, as well as the Metabasic Aquiclude. The syncline is bounded by the Rio das Velhas Aquitard to the west and the Granitic-Gneiss Aquifer to the east. Results from a three-dimensional hydrogeological model indicate that the Santa Rita Syncline Aquifer System is recharged annually, with a renewable groundwater volume of approximately 8.6x107 m³/year. The estimated permanent groundwater reserve is 1.1x109 m3. It is further estimated that at least 72.3% of the renewable groundwater reserve contributes to watercourses within the syncline, highlighting its importance in sustaining streamflow within the Doce River Watershed.