Response of the groundwater system to changes in the Dead Sea level

The Dead Sea is an extremely dynamic hydrologic system, where the base level is currently declining at a rate of approximately 1 m/yr. The groundwater level follows this drop within a relatively short time (a few days in the case of the extensive floods in the winter of 1991-1992). The fresh-saline water interface is very shallow, compared to that of the ocean, due to the large density difference between the fresh and saline water bodies. The interface was found to be steeper near the marginal faults, tracked in a time domain electromagnetic geophysical survey, due to the relatively low horizontal hydraulic conductivity at the fault zone. SUTRA code simulations support this result. Near the shoreline of the Dead Sea, a new coastal area is exposed, whereby the main processes are flushing of most of the section and evaporation and precipitation of salts near the surface. The effect of flushing is seen in several in situ profiles that show much lower concentrations than the original Dead Sea brine, which existed only a few decades ago. Preliminary simulations on a larger scale imply that the Dead Sea water level drop will influence groundwater levels at least several kilometers from the shoreline, increasing the hydraulic gradient and thus also the discharge to the Dead Sea.