Out of sight, out of mind. Submarine springs in the Dead Sea — An underappreciated phenomenon

The drastic drop in Dead Sea lake levels during the last few decades has caused the formation of over 6000 dangerous sinkholes along its coasts. Concurrently, retreating shorelines have led to the exposure of an under-explored phenomenon – submarine spring systems. Once exposed on land, these features are labeled as the more familiar geological hazard – i.e. sinkholes, with no distinction between the two. While visually they may seem similar, the underlying formation mechanism is different, as may well be their hazard potential. This study utilizes high-resolution seismic reflection data collected in 1984 when lake levels were some 35 m higher, together with multibeam bathymetric data from 2014, visual observations and water chemistry data from a verified spring system in order to assess the underlying formation mechanisms of these features, their stability and morphology. Results show that the springs are relatively stable and long-lived systems. They “deserve” to be separated from the sinkholes and studied as a distinct phenomenon. The springs discharge into the lake a significant amount of freshwater from the adjacent aquifers and are therefore, a largely underestimated part of its hydrological budget and the connected fresh groundwater resources. The acceptance of submarine springs as a distinct geological phenomenon and their consideration as a major groundwater outlet into the lake will lead to more realistic groundwater resource models of the Judea and Samaria Eastern Mountain aquifer than exist today. This is extremely important given the increase aridification of the area and the increased demand for freshwater resources.