Delineation of Groundwater Potential Zones Using 2-Dimensional Electrical Resistivity Imaging at Universiti Sains Malaysia, Penang, Malaysia

Abstract

Groundwater exploration is increasing in demand, including use in the domestic, industrial and agricultural sectors. The extracted groundwater is an alternative water supply in these sectors. However, there has also been unsuccessful groundwater exploration due to limited subsurface information. Therefore, geophysical methods were applied to obtain subsurface information to determine and classify the subsurface materials using selected geophysical properties. This research aims to evaluate the delineation of potential groundwater zones using 2D electrical resistivity imaging in Universiti Sains Malaysia, Penang Island, Malaysia. Nine resistivity survey lines are conducted within the research area in USM. The geology of the research area is underlain by igneous rock with a centrally located granitic range running in a north-south direction with low-lying elevations ranging from 5 meters to 20 meters above sea level. The electrical resistivity method measures the resistivity distribution by injecting a small current into the ground through two current and potential electrodes, respectively. The voltage reading is measured between two active potential electrodes alternatively. The instrument used for this research is an automated multi-electrode resistivity meter, ABEM Terrameter SAS 4000 system. Apparent resistivity values undergo an inversion process using RES2DINV software to produce the electrical resistivity topography model. The results show the resistivity values ranging from 1Ùm to 20000Ùm. The subsurface materials are classified into four subsurface materials according to the resistivity values ranges: water-saturated zones, topsoil, weathered bedrock, and fresh bedrock. Several anomalies are interpreted as potential water-saturated zones within the project area and suggested as proposed drilling locations for the groundwater drilling program. The extracted groundwater can act as an alternative source for water supplies in Universiti Sains Malaysia.