Identification of subsurface fluid flow using the 2D geoelectric method in Marunda, North Jakarta

Abstract

Jakarta is the most densely populated province in Indonesia and it will grow over time. This overwhelming population causes a decrease in the quality and supply of groundwater. Brines has been discovered in several areas in Jakarta. Several studies conducted by earth science researchers conclude that brine in Jakarta appears from either seawater intrusion or trapped connate water. This study focuses on the use of the geoelectric method to evaluate the groundwater quality problem in Kelurahan Marunda. Methods used in this study are resistivity, self-potential, and groundwater sampling. Conductivity, Salinity, pH and water table elevation are the parameters used in this study. These methods are done to observe subsurface groundwater quality, fluid flow and how far the seawater infiltrated. Based on the result of groundwater data of 40 wells, high conductivity and high salinity zones are found. High conductivity in this area affected mostly by the saline factor indicated by high salinity and neutral pH. The subsoil has low resistivity values showed by 2D resistivity data. Also, self-potential data displays a North-South groundwater subsurface fluid flow 1, 20 km from the coastline. Altogether, these data indicate seawater intrusion in Kelurahan Marunda, North Jakarta.