Groundwater potential zones identification using geoelectrical resistivity sounding and GIS in upper Metro sub-catchment, Malang, Indonesia

Recently, Upper Metro Sub-Catchment and its surroundings have witnessed intensive land investments. The lack of surface water and the human activities of this region increase the demand for groundwater. Several water boreholes were installed to meet the large water needs; however, these boreholes no longer cover the high demand for water due to the increase in population, increase in irrigated areas, and wear and tear on pumps. Therefore, in order to better define the catchment area and find new sites that meet the water quality and quantity requirements, a geoelectrical survey using the electrical resistivity method was carried out in the upper Metro sub-catchment potentials. Using the Schlumberger array, a total of 19 vertical electrical soundings were conducted along 2 profiles. The recorded data were interpreted quantitatively and qualitatively through the use of apparent resistivity maps, geoelectrical pseudo-section analysis, and the established geoelectric sections. In this study, we identified sandstone tuff as an aquifer layer at a depth of 20 - 100 meters. So it can be known that there are 3 zones of groundwater potential consisting of poor, medium, and high.