Delineation of Seawater Intrusion, Using Geo-Electric Resistivity Method, in Shallow Aquifer in Western Part of Makassar, South Sulawesi, Indonesia

The West Coast of Makassar is a very potential area to be developed as a center of economic growth, but on the other hand, these areas are also stored in various environmental problems, one of which is related to the saltwater intrusion. The purpose of this study is to delineate saltwater intrusion and determine the quality of shallow groundwater. The research method includes the field observation by taking geo-electrical resistivity data. The study of the resistivity imaging results clearly showed very low resistivity anomalies (0-5 Ωm) on all profiles of a given depth. The distribution of these low resistivity anomalies is not simple due to their distribution in complex patterns that exhibit as dispersed shapes. The depth of these very low resistivity zones was found to be varied from 15 to 60 m in different profiles. Areas that have experienced seawater intrusion are in parts of Tamalanrea, Ujung Tanah, Tallo, Wajo, Bontoala, Panakukang, Makassar, Rappocini, Mariso, Mamajang and parts of Tamalate District. Based on resistivity analysis, the possible origin of salt water comes from connate water.