Investigation of saline water intrusion: A case study of coastal Bandar Lampung aquifer, Indonesia

Gravity and geoelectric surveys have been carried out to study the influence of bedrock on the presence of aquifers in the southern part of Bandar Lampung. Gravity measurements at 51 points were randomly distributed to get the basin and thickness of sedimentary formations. Two lines of ERT were conducted to determine the presence of the aquifer in coastal and recharge areas. The ERT measurement uses a Wenner-Schlumberger configuration with space between electrodes 5 m. Geoelectric mapping results identify coastal aquifers at a depth of 3 – 20 m with a resistivity value of 12 – 35 Ohm m. The low resistivity on coastal aquifers is caused by seawater intrusion, where the measured value of EC reaches 5400 mS/cm. The radius of the aquifer that has been exposed to seawater reaches 1,5 km from the shoreline.