Eliahu Rosenthal

Ca-chloride brines at common outlets of the Bet Shean-Harod multiple-aquifer system, Israel

Abstract The Bet Shean and Harod Valleys are regional recipients and mixing zones for groundwaters draining into them from a multiple-aquifer system, which includes carbonate and basalt aquifers and deep-seated reservoirs of brine. The outlets of the three aquifers are located at the mountain border separating the valleys from the Gilboa and Ramot Issakhar Mts. The aquifers drain through two types of outlets — unique and common. The latter type is mainly conditioned by the occurrence of fault blocks acting as connecting media between the aquifers. Upon reaching the interconnecting zones, fresh groundwater flowing from carbonate and basalt aquifers intermix, losing their hydrochemical identities. Ca-chloride brines originating from deep-seated and confined reservoirs, leak along the deep-seated faults characterizing the common outlet zones and contaminate the relatively fresh mixing products originating from the three regional aquifers. Two types of dilute Ca-chloride brines were identified in the study area. The Devora type is a hot and hypersaline source brine which was identified at great depth and under very high hydrostatic pressures. This brine could be the residual product of seawater that evaporated during the Cambrian-Cretaceous continental interval and subsequent prolonged interaction with surrounding carbonate rocks. The Neve Ur-type brine seems to be genetically related to the Neogene inland Sdom Sea that preceeded the contemporary Dead Sea.

Hydrochemistry of groundwater at unique outlets of the Bet Shean-Harod multiple-aquifer system, Israel

Abstract The Bet Shean and Harod Valleys are regional recipients and mixing zones for groundwater draining to these valleys from a multiple-aquifer system which includes carbonate and basalt aquifers and deep-seated reservoirs of brine. The outlets of these aquifers are located at the mountain border separating the valleys from the Gilboa and Ramot Issakhar Mts. The aquifers drain through two types of outlets — unique and common. The latter type is mainly conditioned by the occurrence of fault blocks acting as connecting media between the aquifers. Ionic ratios of groundwaters flowing through different carbonate aquifers have not sufficient contrast to facilitate precise identification of source aquifers. In the case of basalt aquifers, the ratios are unequivocal and sufficient contrast enables such an identification.

Hydrochemical changes induced by overexploitation of groundwater at common outlets of the Bet Shean-Harod multiple-aquifer system, Israel

Abstract The Bet Shean and Harod Valleys are regional recipients and mixing zones for groundwaters draining into them from a multiple-aquifer system which includes carbonate and basalt aquifers and deep-seated reservoirs of brine. The aquifers drain through two types of outlets — unique and common. The latter type is mainly conditioned by the occurrence of fault blocks acting as connecting media between the aquifers. Ca-chloride brines originating from deep-seated and confined reservoirs, leak along the major faults and contaminate the relatively fresh groundwaters originating from the regional aquifers. During the last two decades, the salinity of groundwaters at the outlets of aquifers and in springs discharging into the valleys, have increased as the result of overexploitation. The changes in the chemical composition of these waters indicated inflow of dilute Ca-chloride brines which replace at an ever increasing rate the fresh water of the area. The inflow of brines is limited to fault zones and seems to be controlled by the counterpressure of the overlying fresh water. Overexploitation diminishes this counterpressure, thus facilitating the progressive upflow of brines.

Salinity sources of Kefar Uriya wells in the Judea Group aquifer of Israel. Part 1—conceptual hydrogeological model

Abstract In the Yarkon–Taninim groundwater basin, the karstic Judea Group aquifer contains groundwater of high quality. However, in the western wells of the Kefar Uriya area located in the foothills of the Judea Mountains, brackish groundwater was locally encountered. The salinity of this water is caused presumably by two end members designated as the ‘Hazerim’ and ‘Lakhish’ water types. The Hazerim type represents surface water percolating through a highly fractured thin chalky limestone formation overlying the Judea Group aquifer. The salinity of the water derives conjointly from several sources such as leachates from rendzina and grumosols, dissolution of caliche crusts which contain evaporites and of rock debris from the surrounding formations. This surface water percolates downwards into the aquifer through a funnel- or chimney-like mechanism. This local salinization mechanism supercedes another regional process caused by the Lakhish waters. These are essentially diluted brines originating from deep formations in the western parts of the Coastal Plain. The study results show that salinization is not caused by the thick chalky beds of the Senonian Mt Scopus Group overlying the Judea Group aquifer, as traditionally considered but prevalently by aqueous leachates from soils and rock debris. The conceptual qualitative hydrogeological model of the salinization as demonstrated in this study, is supported by a quantitative hydrological model presented in another paper in this volume.

Relationship between the origin of precipitation in the Jordan Rift valley and their geochemical composition

[1] Rainwater was sampled during seven winters at eight sites along the Jordan Rift valley in Israel. The study area is divided into two regions: the northern part located between the Sea of Galilee and the Dead Sea and the southern part between the Dead Sea and the Dead Sea–Red Sea water divide line in the Arava valley. The Dead Sea region is considered as a desert, the northern part of the study area is semidesert whereas the southern region is considered as extreme desert. Good agreement was found between the chemical and isotopic composition of rainwater its sources and air mass trajectories. In the arid areas, the contribution of salts was mainly from local sources (of up to 500 Km in diameter). Significant chemical divergence was found between rainwater deriving from marine air masses characterized by NaCl enrichment and rainwater deriving from continental air masses which are mainly characterized by Ca-carbonate enrichment. Six main marine and continental air mass trajectories were defined, i.e., northern, northwestern, western, southwestern, eastern and local. The northern air mass trajectories contribute more salts than the southwestern air mass trajectories which exhibit the lowest rainwater salinities. The western trajectory is exclusively marine originating from the Mediterranean, while the eastern trajectory is exclusively continental and originates in the Arabian Desert. Rainwater isotopes revealed three chemically differing systems. The western marine trajectories reflect chemical setting associated with East Mediterranean Meteoric Water Line system; the continental air masses are mainly associated with the Mean Meteoric Water Line system; and whenever the eastern component is significant, a Local Meteoric Water Line prevails.

Water and Diplomacy in the Jordan River Basin

Eliahu Rosenthal is a former lecturer and researcher in hydrogeology and hydrogeochemistry at the Department of Geophysics and Planetary Research, Tel Aviv University and at the Israel Hydrological Service. Professor Rosenthal was an expert for UNESCO, the FAO [Food and Agriculture Organization] and WMO [World Meteorological Organization]. Robbie Sabel teaches international law at the Hebrew University of Jerusalem’s Faculty of Law and Department of International Relations. Dr. Sabel is the former legal adviser and deputy director-general of Israel’s Ministry of Foreign Affairs. Both authors participated in the informal dialogue with Jordan on the management of flow in the Yarmuk River before the peace treaty with Jordan was signed and were members of the Israeli delegation negotiating the Israeli–Jordanian Peace Treaty. This article is dedicated to Yaakov Vardi, formerly of TAHAL, Water Planning for Israel. For over two decades he built up and maintained a continuous dialogue on water issues with Jordan. His absolute personal and professional integrity created an atmosphere of mutual confidence and cooperation.

Structure-controlled groundwater flow and salinization paths in the Bet She’an and Harod Valleys, Israel

The Bet She’an and Harod Valleys are regional recipients and mixing zones for groundwater draining to these valleys from a multiple aquifer system. This aquifer system includes two different carbonate aquifers, several groundwater-bearing basalt flows and deep-seated pressurized brine, the upflow of which causes salinization of fresh groundwater bodies. These aquifers drain through two groups of springs. Due to lack of information on the subsurface structure of the valley the flow-paths of groundwater feeding the springs, the initial distribution of salinities along the valley and particularly, the inflow-paths of the brines, have never been understood but were assumed to be fault-controlled. The interpretation of seismic profiles and analysis of gravity anomalies revealed the subsurface structure of the valley and namely the occurrence of a dense network of faults which branch out from those delineating the Jordan-Dead Sea Rift. The faults formed a series of uplifted and down-warped horst-and-graben structures. By joint analysis of structural, hydrological and geochemical evidence, it occurs that groundwater flow-paths leading to the springs emerging in the middle of the Bet She’an Valley are determined by structural elements such as major faults and fault-controlled structures. The penetration of the pressurized Ca-chloride Rift brines and their inflow into fresh groundwater bodies occurs prevalently along the faults outlining the western margins of the Dead Sea Rift Valley and at their intersection with outbranching NW–SE-striking faults.