Water security has been monitored by scientists for a decade owing to decreasing global water supplies [1, 2]. The IPPC (2007, 2014, 2019) aims to promote water resource usage and subsurface water table stability for future generations. Water resource conflicts are linked to border disputes, major dams and reservoirs, environmental issues, and political identities . Background knowledge of a region's geology and current hydrologic state is also critical for developing effective management techniques. Geophysical studies to evaluate the groundwater potential of confined and unconfined aquifers have become standard practice around the globe [4, 5]. Over the past several decades, rapid advances in electronic technology and numerical modeling have made geophysical research approaches for groundwater exploration and aquifer mapping much more feasible .
Hydrology, environmental geology, and geotechnical engineering all employ surface resistivity methods in various contexts [7–9]. Resistivity approaches are recommended to provide a high sample rate and high-quality data for precise target characterization in a geometrically constrained region with severe subsurface conditions. Electrical resistivity techniques are among the most widely used geophysical methods for groundwater evaluation due to their low cost, accessibility, and effectiveness in regions with highly diverse underlying lithologies [10–12]. According to Nag and Ray , GIS and remote sensing techniques are also used for groundwater assessment.
Geophysicists have found that combining drilling data with subsurface resistivity data may be highly advantageous since both hydraulic and electrical aquifer features rely on the pore spaces' structure . Using geophysical data and the Vertical Electrical Sounding (VES) approach for near-surface measurement, the depth and thickness of an aquifer may be approximated with a degree of uncertainty. Calibration of VES data using borehole logs, lithologies and groundwater information enhance reliability . Groundwater flow and aquifer potential in saturated situations may be determined using hydraulic characteristics calculated from pumping tests conducted in drilled boreholes . However, if pumping experiments are not possible, it is feasible to get quantitative estimates of hydraulic characteristics by combining them with hydrogeological data .
Before drilling a borehole, it is also possible to optimize the site of wells to limit the chance of failure or unexpectedly low pumping rates . The electrical resistivity approach has shown to be effective in groundwater identification and usage . It includes extensive information on hydrogeological conditions and groundwater storage.
A physically significant correlation must be applied theoretically or experimentally to decode the aquifer's resistivity distribution into the aquifer Dar Zarrouk parameters [21, 22]. Aquifers containing fresh and saltwater in various regions can be resolved using longitudinal conductance (S), transverse resistance (TR), longitudinal resistivity (Rs), and coefficients of anisotropy (λ) [23, 24]. Several authors have already assessed Aquifer protection capability using Dar Zarrouk functions [25, 26]. Protective capacity measurements may reveal surface zones where pollutants are being transferred straight into an aquifer . Multiple well-logging and pumping tests in boreholes (Tube wells) are important for estimating aquifer characteristics, including transmissivity (T), hydraulic conductivity (K), storage capacity (S), and the formation factor (F) . The aquifer system is calibrated with the VES data using drill logs, borehole lithologies, groundwater information, and hydro-chemical data, enabling it to be better defined [26, 28].
In this study, an attempt has been made to define groundwater potential and map probable zones for fresh groundwater exploration by characterizing underlying lithologies to a depth of 170 m. This work included 13 VES, 5 boreholes, hydrologer data, and pumping tests, with the primary objective being to determine the subsurface lithologies and groundwater potential zone in the region. The underlying lithology, aquifer system, and Dar Zarrouk parameters were identified using the integration of VES, borehole, and hydrologer data sets. The transmissivity, hydraulic conductivity, and storativity of the aquifer system were estimated using the pumping test data.