Integrated Study of Electrical Resistivity Survey and Chemical Analysis to Delineate the Zone of Seawater Intrusion

To delineate the spatial extent of seawater intrusion in a small experimental watershed, electrical resistivity surveys including drilling data and chemical analysis of groundwater were conducted. We classified 30 sounding curves applying to H type into 3 categories according to the relative differences of resistivity magnitude by inversion. We also grouped groundwater samples in 15 shallow wells into 2 types based on the HCO3/Cl and Ca/Na molar ratio by TDS. From the comparison results, combined application of VES method and chemical analysis of groundwater samples would be useful in deriving more reliable information on the zone of seawater intrusion in coastal watershed disregarding little drilling results.