Caracterização geoelétrica de unidades hidrogeológicas em uma porção do município de Santana do Livramento – RS

Abstract

The present work aims at the geophysical characterization of hydrogeological units of the Guará and Botucatu formations belonging to the Guarani Aquifer System, the largest source of groundwater supply in the State of Rio Grande do Sul. Data acquisition was performed using the Eletroresistivity method with the Vertical Electrical Survey (VES) and Schlumberger arrangement. The studies were carried out in the rural area of the municipality of Santana do Livramento. The inversion process in the VES data occurred through the IPI2win software and made it possible to obtain information of the depth resistivity values for each VES. The results were integrated to lithological information of tubular wells of underground water cataloged in SIAGAS-CPRM in order to reduce possible ambiguities in the interpretation of the geoelectrical data. Three geoelectric sections were generated allowing to correlate the units according to the resistivity levels. For the geoelectric section of the main line (LP) the saturated zone was defined and the resistivity in this layer varied from 38 to 44 (Ohm.m). Very similar occurred in the geoelectric sections of the transverse lines (LT-01 and 02) where the saturated zone presents values of resistivity ranging from 39 to 87 (Ohm.m). With the information of resistivity and quota of the VES present in this work was constructed a potentiometric surface map that presented a flow of underground water oriented from the high (northwest) quotas for the low (southeast) quotas since, in a general way , this flow is directly related to the local topography. Thus, the results from this research will contribute to the development of future hydrogeological research in the portion of the study area and its surroundings .