Hydrogeophysical characterization using the transient electromagnetic method (TEM) and the DC resistivity sounding (VES) method was implemented in the central part of Azraq Basin (Qa Basin), Jordan, to identify and map the spatial distribution of shallow fresh and saline groundwater in the upper aquifer systems. The alluvium (Al) and chert limestone (URC) shallow aquifers show different degrees of groundwater salinization. The range of groundwater resistivity varies from 0.06 to 10.8 ohm-m. Saline groundwater was detected at depths between 5 to 30 m where the aquifers have a wide spectrum of resistivity values from 0.14 to 120 ohm-m. The integrated geophysical and hydrogeologic models are significantly correlated in chloride concentration, groundwater resistivity, and aquifer resistivity. Using 1D inversion results from the TEM and VES soundings in addition to quasi-3D modeling (1D spatially constrained inversion) at selected TEM sites, groundwater resistivity variation was attributed to two different salinization mechanisms. First, the spatial distribution of the salt content in mud flat deposits had a significant effect on the groundwater salinity. Second, in situ dissolution of near-surface rock-forming salts occurred at areas away from the mud flat deposits. The proposed hydrogeophysical models revealed the potential effect of both mechanisms in the study area.

The Dead Sea (DS) area faces critical environmental challenges, including saltwater intrusion (SWI), widespread sinkhole formation, and topographic changes, largely driven by declining DS water levels. These hazards adversely affect the region’s stability, hydrosystems, and agricultural facilities. In particular, the Ghor Al-Haditha (GAH) region in southern DS has been severely affected by these challenges. This study focuses on imaging saltwater intrusion pathways and their relationship with structural and hydrological features in the GAH region using the transient electromagnetic (TEM) method. A total of 195 TEM soundings of single-turn loop were conducted, spatially covering an area of 4 × 3 km² with a focus along three key stream channel profiles. The data are interpreted using 1D Occam and Marquardt-Levenberg inversion methods. Results are presented as spatial resistivity models at various depths, complemented by interpreted cross-sections for detailed analysis. The derived subsurface resistivity models reveal a saltwater interface with resistivity values less than 1.0 Ωm, detected at 100 m depth and following subsurface stream channels in the area. The main SWI extends 1.75 km inland in the shallow aquifer, most clearly along a well-defined channel in the central part of the study area and serving as a proxy for illustrating the significance of known and hidden hydrogeological pathways in this region, where higher intrusion rates are observed. Additionally, minor anomalies near fault and concealed fault zones may suggest localized upwelling linked to deeper saltwater migration. At the scale of the geophysical survey, the SWI predominantly encompasses the sinkhole belt, while spatially, it appears to be constrained by two bounding stream systems to the north and south. The mid-region resistivity model highlights a stratified subsurface structure comprising freshwater, brackish, and brine zones, emphasizing the model’s value in understanding aquifer vulnerability and guiding water management strategies in the GAH area.