Identification of Saline Water and Fluid Flow in Tanjung Priok and Koja North Jakarta Using Geoelectric Method

To date the cause of saline water in Jakarta area is still debated. One opinion says that salty ground water is caused by sea water intrusion. Other opinions stated that the salty water appears from connate water. The objective of this study is determining the causes of saline water in North Jakarta, especially in Tanjung Priok and Koja. The method used to describe the subsurface fluid flow and resistivity spread is geoelectric method. The method consists of SP (self potential) for fluid flow and resistivity for distribution of subsurface saline water. The data is processed using RES2DINV software and interpreted with processed SP to produce a cross-section map. The results of these two methods are also supported by geological data and wells data samples as well as gravity data in the form of FHD (first horizontal derivative). The results of the resistivity indicate the presence of saline water at a depth of 5-10 meters which is a shallow aquifer. The saline water in this study area most likely caused by the sea intrusion as the SP results show that the subsurface groundwater flows from North to South. (paper)