Tino Rödiger

Microbial and Chemical Characterization of Underwater Fresh Water Springs in the Dead Sea

Due to its extreme salinity and high Mg concentration the Dead Sea is characterized by a very low density of cells most of which are Archaea. We discovered several underwater fresh to brackish water springs in the Dead Sea harboring dense microbial communities. We provide the first characterization of these communities, discuss their possible origin, hydrochemical environment, energetic resources and the putative biogeochemical pathways they are mediating. Pyrosequencing of the 16S rRNA gene and community fingerprinting methods showed that the spring community originates from the Dead Sea sediments and not from the aquifer. Furthermore, it suggested that there is a dense Archaeal community in the shoreline pore water of the lake. Sequences of bacterial sulfate reducers, nitrifiers iron oxidizers and iron reducers were identified as well. Analysis of white and green biofilms suggested that sulfide oxidation through chemolitotrophy and phototrophy is highly significant. Hyperspectral analysis showed a tight association between abundant green sulfur bacteria and cyanobacteria in the green biofilms. Together, our findings show that the Dead Sea floor harbors diverse microbial communities, part of which is not known from other hypersaline environments. Analysis of the water’s chemistry shows evidence of microbial activity along the path and suggests that the springs supply nitrogen, phosphorus and organic matter to the microbial communities in the Dead Sea. The underwater springs are a newly recognized water source for the Dead Sea. Their input of microorganisms and nutrients needs to be considered in the assessment of possible impact of dilution events of the lake surface waters, such as those that will occur in the future due to the intended establishment of the Red Sea−Dead Sea water conduit.

Numerical analysis of the groundwater regime in the western Dead Sea escarpment, Israel + West Bank

Water is scarce in the semi-arid to arid regions around the Dead Sea, where water supply mostly relies on restricted groundwater resources. Due to increasing population in this region, the regional aquifer system is exposed to additional stress. This results in the continuous decrease in water level of the adjacent Dead Sea. The interaction of an increasing demand for water due to population growth and the decrease of groundwater resources will intensify in the near future. Thus, the water supply situation could worsen significantly unless sustainable water resource management is conducted. In this study, we develop a regional groundwater flow model of the eastern and southern Judea Group Aquifer to investigate the groundwater regime in the western Dead Sea drainage basin of Israel and the West Bank. An extensive geological database was developed and consequently a high-resolution structural model was derived. This structural model was the basis for various groundwater flow scenarios. The objective was to capture the spatial heterogeneity of the aquifer system and to apply these results to the southern part of the study area, which has not been studied in detail until now. As a result we analyzed quantitatively the flow regime, the groundwater mass balance and the hydraulic characteristics (hydraulic conductivity and hydraulic head) of the cretaceous aquifer system and calibrated them with PEST. The calibrated groundwater flow model can be used for integrated groundwater water management purposes in the Dead Sea area, especially within the framework of the SUMAR-Project.

Challenges to estimate surface- and groundwater flow in arid regions: the Dead Sea catchment.

The overall aim of the this study, which was conducted within the framework of the multilateral IWRM project SUMAR, was to expand the scientific basement to quantify surface- and groundwater fluxes towards the hypersaline Dead Sea. The flux significance for the arid vicinity around the Dead Sea is decisive not only for a sustainable management in terms of water availability for future generations but also for the resilience of the unique ecosystems along its coast. Coping with different challenges interdisciplinary methods like (i) hydrogeochemical fingerprinting, (ii) satellite and airborne-based thermal remote sensing, (iii) direct measurement with gauging station in ephemeral wadis and a first multilateral gauging station at the river Jordan, (iv) hydro-bio-geochemical approach at submarine and shore springs along the Dead Sea and (v) hydro(geo)logical modelling contributed to the overall aim. As primary results, we deduce that the following: (i) Within the drainage basins of the Dead Sea, the total mean annual precipitation amounts to 300 mm a(−1) west and to 179 mm a(−1) east of the lake, respectively. (ii) The total mean annual runoff volumes from side wadis (except the Jordan River) entering the Dead Sea is approximately 58–66 × 10(6) m(3) a(−1) (western wadis: 7–15 × 10(6) m(3) a(−1); eastern wadis: 51 × 10(6) m(3) a(−1)). (iii) The modelled groundwater discharge from the upper Cretaceous aquifers in both flanks of the Dead Sea towards the lake amounts to 177 × 10(6) m(3) a(−1). (iv) An unexpected abundance of life in submarine springs exists, which in turn explains microbial moderated geo-bio-chemical processes in the Dead Sea sediments, affecting the highly variable chemical composition of on- and offshore spring waters.The results of this work show a promising enhancement of describing and modelling the Dead Sea basin as a whole.

The SCALEX Campaign: Scale-Crossing Land Surface and Boundary Layer Processes in the TERENO-preAlpine Observatory

AbstractScaleX is a collaborative measurement campaign, collocated with a long-term environmental observatory of the German Terrestrial Environmental Observatories (TERENO) network in the mountainous terrain of the Bavarian Prealps, Germany. The aims of both TERENO and ScaleX include the measurement and modeling of land surface–atmosphere interactions of energy, water, and greenhouse gases. ScaleX is motivated by the recognition that long-term intensive observational research over years or decades must be based on well-proven, mostly automated measurement systems, concentrated in a small number of locations. In contrast, short-term intensive campaigns offer the opportunity to assess spatial distributions and gradients by concentrated instrument deployments, and by mobile sensors (ground and/or airborne) to obtain transects and three-dimensional patterns of atmospheric, surface, or soil variables and processes. Moreover, intensive campaigns are ideal proving grounds for innovative instruments, methods, and...

New perspectives on interdisciplinary earth science at the Dead Sea: The DESERVE project.

The Dead Sea region has faced substantial environmental challenges in recent decades, including water resource scarcity, ~1m annual decreases in the water level, sinkhole development, ascending-brine freshwater pollution, and seismic disturbance risks. Natural processes are significantly affected by human interference as well as by climate change and tectonic developments over the long term. To get a deep understanding of processes and their interactions, innovative scientific approaches that integrate disciplinary research and education are required. The research project DESERVE (Helmholtz Virtual Institute Dead Sea Research Venue) addresses these challenges in an interdisciplinary approach that includes geophysics, hydrology, and meteorology. The project is implemented by a consortium of scientific institutions in neighboring countries of the Dead Sea (Israel, Jordan, Palestine Territories) and participating German Helmholtz Centres (KIT, GFZ, UFZ). A new monitoring network of meteorological, hydrological, and seismic/geodynamic stations has been established, and extensive field research and numerical simulations have been undertaken. For the first time, innovative measurement and modeling techniques have been applied to the extreme conditions of the Dead Sea and its surroundings. The preliminary results show the potential of these methods. First time ever performed eddy covariance measurements give insight into the governing factors of Dead Sea evaporation. High-resolution bathymetric investigations reveal a strong correlation between submarine springs and neo-tectonic patterns. Based on detailed studies of stratigraphy and borehole information, the extension of the subsurface drainage basin of the Dead Sea is now reliably estimated. Originality has been achieved in monitoring flash floods in an arid basin at its outlet and simultaneously in tributaries, supplemented by spatio-temporal rainfall data. Low-altitude, high resolution photogrammetry, allied to satellite image analysis and to geophysical surveys (e.g. shear-wave reflections) has enabled a more detailed characterization of sinkhole morphology and temporal development and the possible subsurface controls thereon. All the above listed efforts and scientific results take place with the interdisciplinary education of young scientists. They are invited to attend joint thematic workshops and winter schools as well as to participate in field experiments.

Multidisciplinary Investigations of the Transboundary Dead Sea Basin and Its Water Resources

Israel, the Palestinian Authorities and Jordan exploit the transboundary water resources of the Dead Sea basin. Our aim was to add reliable numbers to the water budget of the lake, despite the complicated integrative work and data acquisition due to the tense political situation. We here outline four parts of the project that generally concern surface and groundwater influx to the Dead Sea: (i) direct and non-direct measurements and hydrological modelling to quantify surface runoff, (ii) chemical fingerprinting to characterize groundwater origin, flow, and evolution between recharge and discharge areas, (iii) thermal remote sensing approaches to precisely identify location and abundance of groundwater discharge and (iv) groundwater modelling to quantify discharge volumes. The major outcomes are: (i) total mean annual runoff volumes from side wadis (except the Jordan River ) entering the Dead Sea amounts to approximately 58−66 × 106 m3 a−1, (ii) area normalised recharge amounts differ on both sides being ~45 mm/a at the western side and ~32 mm/a at the eastern side, (iii) modelled groundwater discharge volumes from Upper Cretaceous aquifers from both sides are in order of magnitude of 177 × 106 m3 a−1.

Water balance estimation under the challenge of data scarcity in a hyper-arid to Mediterranean region

Water budget analyses are important for the evaluation of the water resources in semi-arid and arid regions. The lack of observed data is the major obstacle for hydrological modelling in arid regions. The aim of this study is the analysis and calculation of the natural water resources of the Western Dead Sea subsurface catchment, one which is highly sensitive to rainfall resulting in highly variable temporal and spatial groundwater recharge. We focus on the subsurface catchment and subsequently apply the findings to a large-scale groundwater flow model to estimate the groundwater discharge to the Dead Sea. We apply a semi-distributed hydrological model (J2000g), originally developed for the Mediterranean, to the hyper-arid region of the Western Dead Sea catchment, where runoff data and meteorological records are sparsely available. The challenge is to simulate the water budget, where the localized nature of extreme rainstorms together with sparse runoff data results in few observed runoff and recharge events. To overcome the scarcity of climate input data we enhance the database with mean monthly rainfall data. The rainfall data of two satellites are shown to be unsuitable to fill the missing rainfall data due to underrepresentation of the steep hydrological gradient and temporal resolution. Hydrological models need to be calibrated against measured values, hence the absence of adequate data can be problematic. Therefore, our calibration approach is based on a nested strategy of diverse observations. We calculate a direct surface runoff of the Western Dead Sea surface area (1801 km2) of 3.4 mm/a and an average recharge (36.7 mm/a) for the 3816 km2 subsurface drainage basin of the Cretaceous aquifer system.

Assessing anthropogenic impacts on limited water resources under semi-arid conditions: three-dimensional transient regional modelling in Jordan

Both increasing aridity and population growth strongly stress freshwater resources in semi-arid areas such as Jordan. The country’s second largest governorate, Irbid, with over 1 million inhabitants, is already suffering from an annual water deficit of 25 million cubic meters (MCM). The population is expected to double within the next 20 years. Even without the large number of refugees from Syria, the deficit will likely increase to more then 50 MCM per year by 2035 The Governorate’s exclusive resource is groundwater, abstracted by the extensive Al Arab and Kufr Asad well fields. This study presents the first three-dimensional transient regional groundwater flow model of the entire Wadi al Arab to answer important questions regarding the dynamic quality and availability of water within the catchment. Emphasis is given to the calculation and validation of the dynamic groundwater recharge, derived from a multi-proxy approach, including (1) a hydrological model covering a 30-years dataset, (2) groundwater level measurements and (3) information about springs. The model enables evaluation of the impact of abstraction on the flow regime and the groundwater budget of the resource. Sensitivity analyses of controlling parameters indicate that intense abstraction in the southern part of the Wadi al Arab system can result in critical water-level drops of 10 m at a distance of 16 km from the production wells. Moreover, modelling results suggest that observed head fluctuations are strongly controlled by anthropogenic abstraction rather than variable recharge rates due to climate changes.RésuméTant l’augmentation de l’aridité que la croissance de la population posent un problème important concernant les ressources en eau douce dans des zones semi-arides, telle que la Jordanie. Le deuxième plus grand gouvernorat du pays, Irbid, avec plus d’un million d’habitants, souffre déjà d’un déficit hydrique annuel de 25 millions de mètres cubes (MCM). La population devrait doubler dans les 20 prochaines années. Même sans le grand nombre de réfugiés de Syrie, le déficit augmentera vraisemblablement à plus de 50 MCM par année d’ici 2035. La ressource exclusive du Gouvernorat est l’eau souterraine, exploitée à partir de vastes champs captants d’Al Arab et de Kufr Asad. Cette étude présente le premier modèle d’écoulement régional tridimensionnel en régime transitoire de l’ensemble du Wadi al Arab pour répondre aux importantes questions concernant la qualité dynamique et la disponibilité de l’eau au sein du bassin. L’accent est mis sur le calcul et la validation de la recharge dynamique des eaux souterraines, dérivés d’une approche multi-proxy, comprenant (1) un modèle hydrologique concernant un ensemble de données de 30 ans, (2) des mesures de niveaux d’eau souterraine et (3) des informations sur les sources. Le modèle permet d’évaluer l’impact des prélèvements sur le régime d’écoulement et sur le bilan des ressources en eau souterraine. Les analyses de sensibilité des paramètres de contrôle indiquent que des prélèvements intenses dans la partie sud du système du Wadi al Arab peut entraîner des diminutions sévères du niveau d’eau de 10 m à une distance de 16km des puits de production. En outre, les résultats du modèle suggèrent que les fluctuations de la charge hydraulique sont fortement contrôlées par les prélèvements anthropiques plutôt que par des taux de recharge variables associées au changement climatique.ResumenTanto la creciente aridez como el crecimiento demográfico hacen énfasis en los recursos de agua dulce en las zonas semiáridas, como Jordania. La segunda mayor gobernación del país, Irbid, con más de 1 millón de habitantes, ya sufre un déficit hídrico anual de 25 millones de metros cúbicos (MCM). Se espera que la población se duplique en los próximos 20 años. Incluso sin el gran número de refugiados de Siria, el déficit probablemente aumentará a más de 50 MCM por año para 2035. El recurso exclusivo de la gobernación es el agua subterránea, que se extrae en los extensos campos de pozos de Al Arab y Kufr Asad. Este estudio presenta el primer modelo tridimensional transitorio de flujo de agua subterránea de todo el Wadi al Arab para responder a preguntas importantes sobre la dinámica, calidad y la disponibilidad de agua dentro de la cuenca. Se hace hincapié en el cálculo y validación de la dinámica de la recarga del agua subterránea, derivada de un enfoque multi-proxy, que incluye: (1) un modelo hidrológico que cubre un conjunto de datos de 30 años; (2) medidas de nivel de agua subterránea y (3) información acerca de los manantiales. El modelo permite evaluar el impacto de la extracción sobre el régimen de flujo y el balance del agua subterránea del recurso. Los análisis de sensibilidad de los parámetros de control indican que la intensa extracción en la parte sur del sistema de Wadi al Arab puede resultar en descensos de nivel de agua de 10 m a una distancia de 16 km de los pozos de producción. Por otra parte, los resultados del modelado sugieren que las fluctuaciones observadas en la carga hidráulica están fuertemente controladas por la extracción antropogénica más que por las tasas variables de recarga debido a los cambios climáticos.摘要日益增加的干旱和人口增长使半干旱地区的淡水资源倍感紧张,诸如约旦。该国的第二大省伊尔比德人口超过100万,早已经受着每年缺水2500万立方水的痛苦。预计未来20年内人口是现在的两倍。即使没有大量来自叙利亚的难民,到2030年每年的水短缺将超过5000万立方。省内的唯一资源是地下水,被广阔的Al Arab 和 Kufr Asad井场抽取。本研究提出了整个Al Arab 和 Kufr Asad地区第一个三维瞬时区域地下水流模型,以回答有关流域内水的动态水质及可用量的重要问题。强调了根据多代理方法得到的动态地下水补给量的计算和验证结果,多代理方法包括:(1)包含30年数据集的水文模型;(2)地下水位测量及(3)有关泉的信息。模型能够评价抽水对水流场及资源的地下水平衡的影响。控制参数的灵敏度分析表明,干谷al Arab系统南部的强烈抽水可导致距抽水井16公里的地方水位下降10米。此外,模拟结果显示,观测到的水头波动受到人为抽水的强烈控制,而不是受到由于气候变化导致的变化着的补给量的控制。ResumoTanto a crescente aridez quanto o crescimento populacional estressam fortemente os recursos de água doce em áreas semiáridas, como a Jordânia. A segunda maior província do país, Irbid, com mais de 1 milhão de habitantes, já sofre com um déficit hídrico anual de 25 milhões de metros cúbicos (MMC). Espera-se que a população dobre nos próximos 20 anos. Mesmo sem o grande número de refugiados da Síria, o déficit provavelmente aumentará para mais de 50 MMC por ano até 2035. O recurso exclusivo da província é agua subterrânea, abstraída pelos extensivos campos de poços Al Arab e Kufr Asad. Esse estudo apresenta o primeiro modelo transiente regional tridimensional de fluxo das águas subterrâneas de todo o Wadi al Arab para responder importantes questões a respeito da qualidade dinâmica e disponibilidade de água dentro da bacia hidrográfica. A ênfase é dada ao cálculo e validação da recarga dinâmica das águas subterrâneas, derivada de uma abordagem multi-proxy, incluindo (1) um modelo hidrológico incluindo um conjunto de dados de 30 anos, (2) medições de nível das águas subterrâneas e (3) informações sobre nascentes. O modelo permite a avaliação do impacto da abstração no regime de fluxo e no balanço de águas subterrâneas do manancial. A análise de sensibilidade de parâmetros controlados indica que a extração intensa na parte sul do sistema Wadi al Arab pode resultar em quedas críticas do nível freático de 10 m a uma distância de 16 km dos poços de produção. Além disso, os resultados da modelagem sugerem que as flutuações das cargas observadas são fortemente controladas pela abstração antropogênica ao invés de taxas de recarga variáveis devido a alterações climáticas.

The effect of hydraulic anisotropies on intensely exploited groundwater resources: the numerical evaluation of a hydrothermal transboundary aquifer system in the Middle East

Previous investigations postulate the presence of a zone of high hydraulic anisotropy parallel to the principle axis of the Lower Yarmouk Gorge (LYG) in the Middle East. Driven by mixed convection, heated fresh groundwaters ascend within the gorge from confined Cretaceous units through artesian wells and Hammat Gader springs. Two-dimensional transient numerical simulations of coupled fluid flow and heat transport processes are used to investigate the impact of (1) a zone of hydraulic anisotropy and (2) abstraction on hydraulic heads and temperature profiles in the shallow aquifers. The models successfully reproduce hydraulic head distribution pre- and post-groundwater abstraction; dominance of conductive and advective heat transport processes is also shown. The models further support the existence of a structural feature along the principle axis of the gorge, which hydraulically connects groundwaters in both flanks, while cross flow of groundwaters is prevented. That implies a subsurface anisotropic zone, which lets the gorge act as a complex conduit-barrier system where adjacent N–S and S–N flow-fields confluence and get drained towards the Jordan Rift. The present numerical investigations support the hypothesis that, most likely, structural features that represent physical anisotropies control the hydrothermal system of the LYG. Furthermore, the study provides an example of numerical investigation of a complex transboundary aquifer system, with emphasis on existent anisotropies, structural ambivalence and restricted field accessibility.RésuméDe précédentes recherches postulent la présence d’une zone d’importante anisotropie hydraulique parallèle à l’axe principal des gorges du Yarmouk inférieur (LYG) dans le Moyen-Orient. Mues par une convection mixte, les eaux douces souterraines chaudes montent dans les gorges à partir des unités crétacées captives, par les puits artésiens et les sources de Hammat Gader. Des simulations numériques transitoires bidimensionnelles des procédés couplés de flux de fluide et de transport de la chaleur sont employées pour étudier l’impact (1) d’une zone d’anisotropie hydraulique et (2) des prélèvements sur les charges hydrauliques et les profils de température dans les aquifères peu profonds. Les modèles reproduisent avec succès la distribution des charges hydrauliques avant et après les prélèvements d’eaux souterraines; la dominance des procédés de conduction et d’advection dans le transport de la chaleur est. également montrée. De plus, les modèles soutiennent l’idée de l’existence d’un dispositif structural le long de l’axe principal des gorges, qui relie hydrauliquement les eaux souterraines des deux flancs, tandis l’écoulement transverse des eaux souterraines est. empêché. Cela suppose une zone anisotrope souterraine, qui laisse les gorges agir en tant que système complexe de conduit-barrière où les champs d’écoulements adjacents N–S et S–N confluent et sont drainés par le rift jordanien. Les investigations numériques actuelles soutiennent l’hypothèse que, le plus probablement, les éléments structuraux qui représentent des anisotropies physiques commandent le système hydrothermal du LYG. En outre, l’étude fournit un exemple de recherche numérique sur un système aquifère transfrontalier complexe, en mettant l’accent sur les anisotropies existantes, l’ambivalence structurale et une accessibilité restreinte au terrain.ResumenLas investigaciones previas postulan la presencia de una zona de alta anisotropía hidráulica paralela al eje principal de Lower Yarmouk Gorge (LYG) en el Medio Oriente. Impulsado por la convección mixta, las aguas subterráneas dulces calientes ascienden dentro de la garganta desde unidades confinadas del Cretácico a través de pozos artesianos y manantiales de Hammat Gader. Se utilizan simulaciones numéricas bidimensionales transitorias de procesos acoplados de flujo de fluidos y transporte de calor para investigar el impacto de (1) una zona de anisotropía hidráulica y (2) captación sobre cargas hidráulicas y perfiles de temperatura en los acuíferos poco profundos. Los modelos reproducen con éxito la distribución de la carga hidráulica antes y después de la extracción del agua subterránea; también se muestra el dominio de los procesos de transporte de calor conductivo y advectivo. Los modelos respaldan además la existencia de una característica estructural a lo largo del eje principal de la garganta, que conecta hidráulicamente las aguas subterráneas en ambos flancos, mientras que se evita el flujo cruzado de las aguas subterráneas. Eso implica una zona anisotrópica en el subsuelo, que permite que la garganta actúe como un complejo sistema de barrera de conductos donde confluyen los campos de flujo adyacentes N–S y S–N y se drenan hacia el Jordan Rift. Las investigaciones numéricas actuales respaldan la hipótesis de que, muy probablemente, las características estructurales que representan anisotropías físicas controlan el sistema hidrotermal del LYG. Además, el estudio proporciona un ejemplo de investigación numérica de un complejo sistema acuífero transfronterizo, con énfasis en las anisotropías existentes, la ambivalencia estructural y la accesibilidad restringida al campo.摘要在中东,过去的研究假定存在着一个平行于Yarmouk峡谷下游主轴的高度水力各向异性带。受到混合对流的驱使,加热的地下淡水通过自流井和Hammat Gader泉群从承压白垩纪单元向外涌出,其水位在峡谷内抬升。采用耦合液体流和热传送过程二维瞬时数值模拟调查了(1)水力各向异性带和(2)抽水对浅层含水层水头和温度剖面的影响。模型成功地再现了抽水前后的水头分布;还显示出传导和平流热传输过程转主导地位。模型进一步支持沿峡谷的主轴存在着一个构造特征,在地下水交叉水流受到阻碍时,这个构造特征就会水力上连接两岸的地下水。这意味着在地表以下存在着一个各向异性带,这个各向异性带能够使峡谷担当一个复杂的通道屏障系统,在这里毗邻的N–S 和 S–N流场汇合,并且向约旦裂谷排水。目前的数值调查结果支持这一假设,即很可能代表物理各向异性的构造特征控制着Yarmouk峡谷下游水热系统。此外,研究还为复杂的跨边界含水层系统的数值调查,尤其是侧重现有的各向异性、构造上各种情况并存以及抵达野外场地受限的数值调查提供了样板。ResumoInvestigações anteriores postulam a presença de uma zona de elevada anisotropia hidráulica paralela ao eixo principal do Baixo Desfiladeiro de Yarmouk (BDY), no oriente médio. Conduzidas por convecção mista, as águas subterrâneas aquecidas ascendem dentro do desfiladeiro de Unidades Cretáceas através de poços artesianos e nas nascentes de Hammat Gader. Simulações numéricas de transiente bidimensional de processos de fluxo de fluidos e transporte de calor acoplados são utilizados para investigar os impactos de (1) uma zona de anisotropia hidráulica e (2) explotação nas alturas piezométricas e perfis de temperatura em aquíferos rasos. Os modelos reproduzem com sucesso a distribuição da altura piezométrica pré e pós a explotação; é mostrada também a dominância de processos condutivos e convectivos de transporte de calor. Os modelos suportam ainda a existência de uma feição estrutural ao longo do eixo principal do desfiladeiro, com águas subterrâneas hidraulicamente conectadas em ambos os flancos, enquanto o fluxo cruzado de águas subterrâneas é impedido. Isso implica numa zona anisotrópica subsuperficial, o que permite que o desfiladeiro atue como um complexo sistema conduto-barreira, onde ocorre confluência de fluxos N–S e S–N adjacentes e são drenados para a Fenda do Jordão. A investigação numérica presente apoia a hipótese de que, muito provavelmente, feições estruturais que representam anisotropias físicas controlam o sistema hidrotermal do BDY. Além disso, o estudo fornece um exemplo de investigação numérica de um complexo sistema aquífero transfronteiriço, com ênfase nas anisotropias existentes, ambivalência estrutural e de restrita acessibilidade.

Investigating the complex hydrogeological settings in the northeastern slope of the West Bank to the Jordan Graben (Malih and Jeftlik)

The northeastern part of the West Bank is located between brackish water sources in the Jordan Rift to the east, and the freshwater drainage from the mountain ridge, where the complex geological structure can facilitate a possible flow-path connecting different fresh and saline water bodies, saline sources, and the regional aquifers, which are the sources of their freshwater. Integrated stable and radioactive isotopic tools of tritium (3H), carbon (14C), carbon (δ13C), sulphur (δ34S) deuterium (δ2H) and oxygen (δ18O) were used to investigate the effect of complex geologic structure on the groundwater residence times, and respective potential sources, mixing, and recharge mechanisms. The low 14C values in the Malih and Marj Najeh area suggest mixing signatures between the old brine and the fresh water that conveyed from Cretaceous rocks and Eocene mountain aquifer in the west through the faults that intersect the water flow path to the north, toward the study area. The study differentiates between two salinity mechanisms, one that is coming from dissolution of saline sediments and salinized the triggered freshwater along with Faria flow path with high 14C pMC values and positive δ34Ssulphate and the second is the deep-seated pressurized CaCl2 brine, the upflow of which causes salinization of fresh groundwater bodies entering the system.