The southern Arava Rift Valley forms a regional desert drainage basin through which both surface and groundwater are drained southward to the Gulf of Elat (Aqaba). Intensive production of water in the area, which is mostly used as raw material for desalination, has caused significant drops in water levels accompanied by a certain increase in salinity at the main production sites. Chemical and isotopic characteristics indicate that the regional alluvial aquifer in the Rift Valley is a mixing product of two components, fresh and saline. The local saline end-member always determines the geochemical solute affinity, whereas the stable isotopic composition reflects the external freshwater sources that determine the regional groundwater flow regime and their mixing proportions. These include the Nubian aquifer to the west of the Rift and the seasonal rainwater precipitated over Mount Edom, which is conveyed to the Rift through the alluvial fans developed along its eastern rift margins. The Nubian aquifer, which comprises the Kurnub and the Yam-Suf groups contains, "paleowater" attributed to recharge in a different climatic regime which prevailed over its intake area in southern Sinai during some periods of the Quaternary. A three-dimensional computational model representing the hydrogeological configuration of the area was constructed and calibrated against available historical data, which is not evenly distributed in the area. The model was constrained with additional "soft" information about the flow regime in the area. The calibrated model was used to explore the quantitative aspects of the resource in question and assist in designing an optimal and sustainable exploitation policy. The production scheme considered the specific conditions of the area, namely, that almost all the water produced is consumed as source water for desalination and therefore is less sensitive to gradual salinity increase. The results suggest that an intensified production scheme in which exploitation is almost doubled could be executed without inducing a significant worsening of the present situation. Finally, a preferred alternative could be identified, while minimizing the damage due to the overexploitation of the aquifer.
ASJC Scopus subject areas
- Earth and Planetary Sciences (all)