The hydrogeological subprovinces of the Bauru aquifer in the North-western region of the State of São Paulo

Abstract

The growing exploration of de subterranean water resources of the northwestern region of the Statt of São Paulo has revealed great variations in the productivity of open wells in the Bauru aquifer. Proceeding from a detailed study of the lithology, sedimentary structures and stratigraphic behavior of the Bauru Group which covers the region studied, it was verified that this variation is determined rather by the geological characteristics of the Bauru sediments than by the different technical pattern of the wells bored in it. The data obtained establishes, as fundamental causes of this variation, porosity and permeability which vary in function, of the texture, content and behavior of the carbonate ciment of the rocks. It was also verified that the variation in productivity of the Bauru aquifer has regional significance, that is, it represents diverse values in different areas. Based in this fact, the authors were able to establish the existence of at least three hydrogeological provinces in the region studitd, delimiting, although only provisionally, areas more and less promising for the exploration of subterranean water.