The relationship between saline groundwater within the Arava Rift Valley in Israel and the present and ancient base levels as detected by deep geoelectromagnetic soundings

Abstract

The time domain electromagnetic (TDEM) geophysical method was employed to detect saline groundwater bodies within and in the close margins of the Arava Rift Valley. The Arava Valley aquifers are known to occupy fresh to saline groundwater. The lateral subsurface inflow to the Arava from west and east is characterized by fresh to brackish waters. The results of the present study indicate that salination of groundwater is controlled by both present day and ancient base levels, namely by the Dead Sea in the north and by the Gulf of Elat in the south. The configuration obtained by the TDEM survey exhibits interfaces and palaeo-interfaces between fresh to brackish waters and underlying seawater or diluted seawater intruded inland from both base levels as well as brines intruded from the northern base level. The central Arava structural and hydrological divide seems to escape seawater or brine encroachment at least to the considerable depth of the TDEM measurements.