Compartmentation in the Guarani Aquifer System northeastern region of the Rio Grande do Sul State

This study aims to evaluate the structural compartmentation of the Guarani Aquifer System (GAS) in the northeastern region of the Rio Grande do Sul (RS) state. For this purpose, an integrated analysis of 747 morphostructural lineaments identified in the scale 1:1,000,000 with geometry features and potentiometry of the GAS was performed. Based on this evaluation, a main set of structures, N30W and N60E oriented, responsible for the GAS compartmentation within the study area, was identified. These directions are related to the main tectonic structures that originated from the basement of the Paraná Basin, which could indicate that these identified structures are part of large fault systems in this region. The variations in the GAS potentiometry and altimetry of the top related to the compartmentation show the existence of several blocks formed under the influence of NW and NE structures located mainly in the large valleys, which sometimes work as a discharge zone of the aquifer. According to the analysis, the GAS in the northeastern region of RS seems to be divided into compartments of different sizes. This structural and geometrical framework imposed by tectonic structures influences the GAS potentiometry and flow dynamics.