Hydrochemistry types of the Bauru Aquifer System in the State of São Paulo

Abstract

Groundwater is used for public supply in 55% of Brazilian municipalities. In the state of São Paulo approximately 72% of the cities, with an estimated population of 5.5 million inhabitants, are fully or partially supplied by groundwater, being Bauru Aquifer System the most widely used aquifer. This paper presents a hydrochemistry characterization and classification of four aquifer units which comprises the Bauru Aquifer System in the São Paulo state. The studies were carried out in the region of the Cretaceous sedimentary occurrence of the Bauru Group and groundwater sampling was executed in strategically selected water wells. Sampling wells were preferably selected based on single aquifer unit production and regionally distributed. Chemical analyses from previous studies were incorporated in order to provide an integrated hydrochemistry characterization of the Bauru Aquifer System. Calcium and sodium bicarbonate waters are the dominant hydrochemistry types, followed by calcium sulfate and sodium chloride. The Caiuá Aquifer waters are the least saline and those of Santo Anastácio Aquifer the most mineralized.

Keywords

• Sistema Aquífero Bauru. Hidroquímica. Água Subterrânea.