Geoelectrical survey and cone penetration test data for groundwater potential determination around Gatot Subroto Street, Banjarmasin

Abstract

Subsurface condition evaluation is often relied to answer various necessities in a community, such as groundwater potential determination as a source of water supply. One of the most utilized method for this purpose is the geoelectrical method due to its efficiency, cost effectivity, and non-invasive nature. Geoelectrical method can also be used in tandem with geotechnical method, such as the Cone Penetration Test (CPT). In this study, a geoelectrical survey has been conducted in Gatot Subroto Street, Balikpapan. The survey uses 3 geoelectrical configurations: Dipole-Dipole, Wenner-Alpha, and Wenner-Schlumberger, which was performed using MAE type X-612EM+ with 24 electodes and 2 m spacing between electrodes. Soil quality assessment has also been conducted at the location from 0 to 29 m of depth using CPT. After geoelectrical survey had been done, the data would then be interpreted along with CPT data to project subsurface condition around the studied location. Based on the observation of the geoelectrical survey up to 6 m of depth, there are areas showing low resistivity value of <100 Ωm, characterizing that the layer is dominated by clay. In addition, groundwater potential is also found at a depth of ±2 m and characterized by a very low resistivity value of < 1.7 Ωm. Furthermore, CPT data classifies the soil layer from 0 to 19.40 m as very soft clay. These results infer strong correlation between geoelectrical and CPT data at the observed location.