Groundwater Detection Using Resistivity at Nubutautau Village in Viti Levu in Fiji

Abstract

A geophysical method, electrical resistivity tomography, was applied to identify potential groundwater-bearing zones around Nubutautau village on Viti Levu island, Fiji. Apparent resistivity data of the subsurface were collected through an electrode assembly along survey lines by injecting current into the subsurface using an ABEM Terrameter LS2. The apparent resistivity data were inverted using Res2DINVx64 software to produce the final electrical resistivity through an iterative process to compare the resistivity of layers and draw analogical hydrogeological results. Analysis revealed the presence of two potential groundwater-bearing zones as potential targets for future drilling. The two targets indicated the presence of potentially saturated vertical fractures through which infiltrating rainwater percolates through the volcanic rock towards a deeper basal aquifer. The identification of the two potential targets demonstrated great potential of this geophysical technique to effectively inform drilling operations. A scientific approach can increase the successful delivery of water security interventions in remote, drought-prone communities of the Pacific.