The portion of the Hydrographic Region of Uruguay River situated between the Rio Grande do Sul and Santa Catarina states are being evaluated as potential of hydric resources for hydroeletric enterprises. The City of Erechim is located between the coordinates 27° 29’ 20” S; 52° 10’ 03”W and 27° 47’ 15”S; 52° 21’ 52” W, northwest region of the state, is part of the volcanic spills of the Serra Geral Formation, Fácies Paranapanema in the Paraná basin. The uses of ground waters in the Hydrografic Region of Uruguay are multiple: human, animal supplying, hydrothermal waters, irrigation, mineral water bottling. However, the risk of contamination of ground waters comes together with its growing demand, fact that indicates the necessity of this resource management. This work has as objective to evaluate and to spatialize in cartograms GOD system for evaluation of aquifer pollution vulnerability of the Serra Geral Aquifer System/SASG, forming one unconfined fissural aquifer at outcrops near surface. Of a total of 99 tubular wells registered in cadastre in the System of Ground Water Information SIAGAS/CPRM, the GOD system for evaluation ofaquifer pollution vulnerability was applied in 55 wells. The cartograms had been generated in the software 8.0 Surfer and ArcGIS 9.3, represented in the Universal System Transversa de Mercator/UTM. The GOD system for evaluation of aquifer pollution vulnerability showed 47 wells inserted in the class of average vulnerability, representing about 85.5% of the total area evaluated of 430.76 km ². The class low occupied 12.7% of the area and only 1.8% were inserted in the negligible class. The layer of variation of the potenciometric quota was between 416 and 780 meters, being observed the occurrence of high regional potenciometrics and low potenciometrics locals. The regional direction of underground flow was in the direction southeast - northeast, for the gutter of the Uruguay River. .
