Detailed geology for the elaboration of a conceptual model of groundwater circulation: case study in Jurubatuba, SP.

Abstract

The São Paulo Metropolitan Region consists of a highly populated and industrialized area, where there are hundreds of deep wells that supply the region with the waters of the Aquifer Crystalline. In the Jurubatuba channel industrial area, the aquifer is contaminated with high concentrations of chlorinated solvents, representing a risk to the local population. Solving this problem is a challenge for the field of hydrogeology, due to the complexity of flow in fractured aquifers and to the high toxicity and mobility of contaminants; the contaminants can reach great depths as they are denser and less viscous than water. In this sense, the conceptual hydrogeological modeling becomes essential in order to predict the preferential flow pathways of groundwater and contaminants through the hydraulically active fractures. This procedure has been shown effective in studies conducted abroad, focused on the investigation of fractured aquifers contaminated by chlorinated solvents. The structural analysis, which includes the application of new research technologies such as geophysical surveys in wells, allow the characterization of geometric parameters of the fracture network, as well as the identification of geological conditions that control the circulation of water in fractured aquifers. This analysis will allow the development of a groundwater flow conceptual model, which will form the basis for the research of the contaminant transport to be held in the same region under a larger project (Gesol). The combined use of different methods of investigation warrants the innovative character of the work in Brasil, and its results will contribute for the planning of future investigations.