Transient electromagnetic imaging of saltwater intrusion at the shrinking Dead Sea

Abstract

Abstract 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.