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Accueil du site → Doctorat → Allemagne → 2011 → Tracing flow and salinization processes at selected locations of Israel and the West Bank - the Judea Group Aquifer and the Shallow Aquifer of Jericho

Technische Universitaet Bergakademie Freiberg (2011)

Tracing flow and salinization processes at selected locations of Israel and the West Bank - the Judea Group Aquifer and the Shallow Aquifer of Jericho

Lange, Torsten

Titre : Tracing flow and salinization processes at selected locations of Israel and the West Bank - the Judea Group Aquifer and the Shallow Aquifer of Jericho.

Auteur : Lange, Torsten

Université de soutenance : Technische Universitaet Bergakademie Freiberg

Grade : Doctor of Philosophy (PhD) 2011

Due to the low amount or unfavorable annual distribution of precipitation the exploration, allocation, sustainable exploitation, and protection of replenishable as well as fossile water resources are challanging tasks in semiarid and arid regions. Beside a few natural or artificial surface water reservoirs the porous underground at the same time is the largest storage and transport medium for water and provides protection against evaporation and to a certain degree against surficial introduction of contaminants. This situation is characteristic for the Near East and thus for the selected investigation areas, that are located in Israel and the West Bank, and that are subject of the conducted partail studies that are presented. The work focuses on three main subjects. On the one hand, it deals with the characterization of the young groundwater components of the discharge of four major springs of Wadi Qilt and Jericho, as well as of sampled deep wells of three important well fields. All of these objects discharge or abstract water from the Upper and Lower Judea Group Aquifer. With a thickness of about 750 m it is one of the most important groundwater reservoirs of the region and comprises mainly to varying degrees karstified and fractured limestones and dolomites. These formations underwent uplift during Senonian to Eocenian times forming a pair of double-plunging anticlinal structures (Hebron and Ramallah or Judea and Samaria Mountains, respectively) that are again subdivided into minor anticlines and synclines. The groundwater replenishment is restricted to the winter season between October and April, and to the crestal area of the mountains, where the otherwise covered aquifer rocks crop out. A strategy was developed to interpret the applied tracers for all locations in a similar way using a lumped parameter approach, which enables a direct comparison. On the other hand, the work investigates salinization processes in the Shallow Aquifer of Jericho and their discrimination. Potential sources for salinization are remnant brines that are activated to flow into the range of well extraction due to groundwater overexploitation, dissolution of salts or formation waters from the Lisan formation. These layers represent the sediments of Lake Lisan, the Pleistocene precursor of the Dead Sea. A discrimination of the salinization mechanisms is important to develope reasonable measures to limit or lower the salt concentration in the affected wells. Consequently, the relevant measured but also potential main hydrochemical indicators and isotope tracers are identified. The large uncertainties with respect to the establishment of a well-founded water balance and to the insufficient knowledge about the geology of the small-scale area of Jericho are discussed. Because the interpretation of the measured helium samples from the fractured and karstified aquifer of the Cretaceous Judea Group is limited, the dependencies of the 4He accumulation in groundwater in an idealized dual-continuum aquifer are investigated with respect to the relation of the 4He mass fluxes and the system response time to the varied parameters (groundwater head gradient, hydraulic conductivities, dispersivities, porosities) by means of a sensitivity analysis. Although the system response time is not a system variable as such it clearly turned out that knowledge about it may be an important information for the interpretation of He concentrations in groundwaters of non-stationary systems. To enhance the visual post-processing of the parameter sensitivity analysis an easily interpretable way of data presentation is introduced.

Mots clés : Israel, Westbank, groundwater, Judea Group Aquifer

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