Use of geoelectrical resistivity method for detecting near-surface groundwater potential zones at Riyadh city, Saudi Arabia

Six profiles of the two-dimensional multi-channel electrical resistivity tomography (ERT) were conducted at the northwest part of Riyadh city using the SYSCAL Pro system with a dipole-dipole configuration to detect the near-surface water-bearing potential zones. The ERT field measurements use a series of regu-larly placed electrodes to measure the electrical resistivity along the profile. The results of the inverse models are displayed as cross-sections of the true resistivity distribution of the subsurface with depth along with each profile. The two-dimensional (2-D) inversion results of the electrical resistivity data indi-cate three geoelectric zones; 1st zone of low resistivity values (<100 X.m), representing two groundwater-bearing potential zones from top to bottom as follows; the 1st one extends downwards to 10-and 15-meters depth, while the 2nd zone spreads between 15-and 30-meters depth, 2nd zone with resistivities ranging from 100 to 1000 X.m, which represent the highly fractures limestone; the 3rd zone with resistivities greater than 1000 X.m reflecting compacted limestone rocks. It is noticed also some of the low resistivity pockets are isolated through the subsurface geoelectrical cross-section indi-cating the presence of voids and/or cavities. Based on these results, the investigated area is considered as one of the promising zones for groundwater supply in Riyadh city and its future urbanization expan-sion projects. This can be accessed by drilling wells down to a depth of 50 m for groundwater extraction. (c) 2022 The Authors. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

Six profiles of two-dimensional multi-channel electrical resistivity tomography were conducted in the northwest part of Riyadh city to detect the near-surface water-bearing potential zones. The results identified three geoelectric zones and confirmed the area as a promising zone for groundwater supply.