Assessment of the Intrinsic Vulnerability to Contamination of the Aquifer in River Basin Passo Fundo of Rio Grande do Sul

The progressive pollution of surface water reserves increasingly generates the exploitation of groundwater resources. Based on this, grows the importance of studies that aim to contribute to the qualitative and/or quantitative analysis of these important sources. The present study aims to determine the natural vulnerability of the aquifer to contamination in the watershed of the Passo Fundo river basin, by applying the GOD system. It has been used information from 439 wells registered on the Groundwater Information System. The river basin under study presents a negligible vulnerability in 73,1% of its total area, low in 25,6 %, an average of 1,3 % and high in only 0,01 %. Thus, it can be concluded that the aquifer has a significant natural protection through the basaltic rocks of the Serra Geral Formation, featuring, for the most part, a confining condition to the aquifer.