In coastal areas, the problem of saline intrusion wedge often preclude the use of groundwater for public consumption, thus there is the need to accurately determine the interface of the freshwater / saltwater, in order to preserve quality of this groundwater resource to a balanced and sustainable development. The study of the shape, location and temporal variation of this interface is extremely important for exploitation of underground waters. The quality of these waters is highly susceptible to contamination by socioeconomic activities, use and occupation of the soil, causing contamination of aquifers, which is becoming increasingly common. Currently, a problem that is becoming somewhat common, is the total or partial salinization of these reserves, primarily in the coastal regions. In these regions the contamination is usually persistent, but the recovery of the quality of these waters is very slow and very difficult. So preserving the quality of these reservoirs is very important, forming a framework of ecological balance and sustainable source.In micro Bragantina, specifically in Vila dos Pescadores (NE Pará), we found a very precarious water supply. The residents of this village wells using Amazons style with a very shallow depth, allowing contamination by waste from septic tanks and saltwater intrusion. The use of geophysical methods is a quick and low cost for the environmental diagnosis of these regions. Through radagramas generated by Ground Penetrating Radar (GPR) and 3-D modeling of the two study areas near the Vila dos Pescadores (Bragança, Pará), one can perform the mapping of this problem. These areas of study correspond to the soccer field and beach near the town of Bonifacio. The identification of the groundwater in this environment studied was clear, especially in the first survey of the profiles that match the beach. It was possible to verify the presence of saline intrusion due to the high value of electrical conductivity, caused strong attenuation of electromagnetic wave and for this reason can be mapped.