Controls on the Cl/Cl input ratio of paleo-groundwater in arid environments: New evidence from Kr/Kr data.

Measurements of the long-lived Kr and Cl radioisotopes in groundwater from the Negev Desert (Israel) were used to assess the Cl/Cl input ratios and Cl contents for paleorecharge into the Nubian Sandstone Aquifer (NSA). The reconstructed Cl content of the recharge flux was on the order of 300-400 mg/L. An initial Cl/Cl ratio of 50 × 10 was assessed for the groundwater replenishment in the Negev Desert since the late Pleistocene, in agreement with the Cl/Cl ratios in recent local rainwater.

Harnessing Paleohydrologic Modeling to Solve a Prehistoric Mystery.

A riddle arises at the Epipaleolithic and Neolithic sites that dot the lower Jordan Valley. The area has no water resources yet it has long been a focus of inquiry into the transition from mobile hunter-gatherer to sedentary agriculture-based cultures. How then is there such clear evidence of life here, and particularly at such a critical moment in human evolution? Keen to unravel this conundrum, a numerical hydrological model was devised to simulate the groundwater flow field within the Eastern Aquifer of the Judea and Samaria Mountains during the transition from the last glacial to the current interglacial.

Radiokrypton unveils dual moisture sources of a deep desert aquifer.

In arid regions, groundwater is a vital resource that can also provide a long-term record of the regional water cycle. However, the use of groundwater as a paleoclimate proxy has been limited by the complex hydrology and the lack of appropriate chronometers to determine the recharge time without complication. Applying Kr, a long-lived radioisotope tracer, we investigate the paleohydroclimate and subsurface water storage properties of the Nubian Sandstone Aquifer in the Negev Desert, Israel.

Mitigation of downstream propagation of contaminated water in a carbonate aquifer - The northeastern Negev desert, Israel.

Groundwater pollution in Israel mainly occurs in the populated urban areas. Yet, in the 90's a major salinization was identified in a deep well in the northeastern part of the Negev desert, and a trend of increasing salinity was recognized in an adjacent spring. Since then the salinity of the spring is on the rise reaching a rate of 21 mgCl/L per month.

Massive arrival of desalinated seawater in a regional urban water cycle: A multi-isotope study (B, S, O, H).

"Man-made" or unconventional freshwater, like desalinated seawater or reclaimed effluents, is increasingly introduced into regional water cycles in arid or semi-arid countries. We show that the breakthrough of reverse osmosis-derived freshwater in the largely engineered water cycle of the greater Tel Aviv region (Dan Region) has profoundly changed previous isotope fingerprints. This new component can be traced throughout the system, from the drinking water supply, through sewage, treated effluents, and artificially recharged groundwater at the largest Soil-Aquifer Treatment system in the Middle East (Shafdan) collecting all the Dan region sewage.

Concurrent Salinization and Development of Anoxic Conditions in a Confined Aquifer, Southern Israel.

An ancient, brackish, anoxic, and relatively hot water body exists within the Yarqon-Tanninim Aquifer in southern Israel. A hydrogeological-geochemical conceptual model is presented, whereby the low water quality is the outcome of three conditions that are met simultaneously: (1) Presence of an organic-rich unit with low permeability that overlies and confines the aquifer; the confining unit contains perched horizons with relatively saline water. (2) Local phreatic/roofed conditions within the aquifer that enable seepage of the organic-rich brackish water from above.

Manganese mobilization and enrichment during soil aquifer treatment (SAT) of effluents, the Dan Region Sewage Reclamation Project (Shafdan), Israel.

The composition of groundwater reclaimed from tertiary soil aquifer treatment systems reflects the dynamic processes taking place in the subsurface, between the infiltration basin and the production wells. At the end of year 2000, following more than a decade of operation, high Mn concentrations (2 micromol L(-1) < or = Mn < or = 40 micromol L(-1)) appeared in the reclaimed effluents of the Dan Region Sewage Reclamation Project (Shafdan), Israel. A mass balance indicates that the high Mn excess originated from the aquifer rocks, most likely following reduction of sedimentary Mn-oxides under suboxic conditions.