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Author Krüger, N.; Külls, C.; Bruggeman, A.; Eliades, M.; Christophi, C.; Rigas, M.; Eracleous, T. openurl 
  Title Groundwater recharge estimates with soil isotope profiles-is there a bias on coarse-grained hillslopes? Type Conference Article
  Year 2020 Publication EGU General Assembly Conference Abstracts Abbreviated Journal  
  Volume Issue Pages 9840  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Krueger2020groundwater Serial 42  
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Author Tziritis, E.; Aschonitis, V.; Balacco, G.; Daras, P.; Doulgeris, C.; Fidelibus, M.D.; Gaubi, E.; Gueddari, M.; Güler, C.; Hamzaoui, F.; others openurl 
  Title MEDSAL Project-Salinization of critical groundwater reserves in coastal Mediterranean areas: Identification, risk assessment and sustainable management with the use of integrated modelling and smart ICT tools Type Conference Article
  Year 2020 Publication EGU General Assembly Conference Abstracts Abbreviated Journal  
  Volume Issue Pages 2326  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Tziritis2020medsal Serial 43  
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Author Jin, Z.; Külls, C. doi  openurl
  Title FDM based OA-ICOS for high accuracy 13C quantification in gaseous CO2 Type Journal Article
  Year 2020 Publication Earth and Environmental Science Abbreviated Journal EES  
  Volume 446 Issue 3 Pages 032061  
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  Series Editor Series Title IOP Conference Series Abbreviated Series Title  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Jin2020fdm Serial 16  
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Author Doulgeris, C.; Tziritis, E.; Pisinaras, V.; Panagopoulos, A.; Külls, C. openurl 
  Title Prediction of seawater intrusion to coastal aquifers based on non-dimensional diagrams Type Conference Article
  Year 2020 Publication EGU Geophysical Abstracts Abbreviated Journal  
  Volume Issue Pages 4073  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Doulgeris2020prediction Serial 41  
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Author Christofi, C.; Bruggeman, A.; Külls, C.; Constantinou, C. url  openurl
  Title Isotope hydrology and hydrogeochemical modeling of Troodos Fractured Aquifer, Cyprus: The development of hydrogeological descriptions of observed water types Type Journal Article
  Year 2020 Publication Applied Geochemistry Abbreviated Journal  
  Volume 123 Issue Pages 104780  
  Keywords Isotope hydrology, Hydrogeochemical modelling, Hydrochemistry, Kargiotis, Troodos  
  Abstract The origin of groundwater recharge and subsequent flow paths are often difficult to establish in fractured, multi-lithological, and highly compartmentalized aquifers such as the Troodos Fractured Aquifer (TFA). As the conjunctive use of stable isotopes and hydrogeochemical data provides additional information, we established a monitoring network for stable isotopes in precipitation in Cyprus. The local meteoric water line, altitude effect and seasonal variation of stable isotopes in precipitation are derived from monitoring data. Stable isotopes and hydrogeochemical data are combined to model water-rock interactions and groundwater evolution along a complete ophiolite sequence. As a result a generic hydrogeologic description for the observed water types is developed. Isotope hydrology was applied in conjunction with hydrogeochemical modelling in Kargiotis Watershed, a major north-south transect of the TFA. PHREEQC was used for hydrogeochemical modelling to establish generic descriptions for observed water types. Mean precipitation-weighted values from 16 monitoring stations were used to calculate the Local Meteoric Water Line (LMWL), which was found to be equal to δ2H = (6.58 ± 0.13)*δ18O + (12.64 ± 0.91). A general decrease of 1.22‰ for δ2H and 0.20‰ for δ18O in precipitation was calculated per 100 m altitude. A generic groundwater evolution path was established: 1. Na/MgClHCO3, 2. MgHCO3, 3. Ca/MgHCO3, 4. Ca/MgNaHCO3, 4a. MgNa/CaHCO3/Cl, 5. NaMg/CaHCO3/Cl, 6. NaHCO3, 7. Na/MgHCO3SO4, 8. NaSO4Cl/HCO3. Hydrogeologic descriptions, consisting of groundwater origin, flow path and possible active water-rock processes, have been realised for the observed water types. The first two water types occur in serpentine and ultramafic-gabbro springs. Type 3 waters represent early stages of recharge and/or short flow paths, in gabbro whereas types 4 and 5 are typical for further percolating waters in gabbro and diabase. Water types 6 and 7 occur both in diabase and in the basal group and represent the regional flow. Water type 8 is the end member of regional, upwelling groundwater in the basal group. The presented descriptions and methods have practical applications in groundwater exploration, characterization, and protection. The methodology can be applied in other complex aquifer systems.  
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  Language english Summary Language english Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0883-2927 ISBN Medium  
  Area Cyprus Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ Christofi2020104780 Serial 76  
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Author Mahindawansha, A.; Külls, C.; Kraft, P.; Breuer, L. url  doi
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  Title Investigating unproductive water losses from irrigated agricultural crops in the humid tropics through analyses of stable isotopes of water Type Journal Article
  Year 2020 Publication Hydrology and Earth System Sciences Abbreviated Journal  
  Volume 24 Issue 7 Pages 3627-3642  
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  Publisher Copernicus GmbH Place of Publication Editor  
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  Notes Approved yes  
  Call Number THL @ christoph.kuells @ Mahindawansha2020investigating Serial 14  
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Author Christofi, C.; Bruggeman, A.; Külls, C.; Constantinou, C. url  doi
openurl 
  Title Hydrochemical evolution of groundwater in gabbro of the Troodos Fractured Aquifer. A comprehensive approach Type Journal Article
  Year 2020 Publication Applied Geochemistry Abbreviated Journal  
  Volume 114 Issue Pages 104524  
  Keywords geochemistry  
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  Corporate Author Thesis  
  Publisher Pergamon Place of Publication Editor  
  Language English Summary Language Original Title  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Christofi2020hydrochemical Serial 13  
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Author Bonnetti, C.; Zhou, L.; Riegler, T.; Brugger, J.; Fairclough, M. url  openurl
  Title Large S isotope and trace element fractionations in pyrite of uranium roll front systems result from internally-driven biogeochemical cycle Type Journal Article
  Year 2020 Publication Geochimica et Cosmochimica Acta Abbreviated Journal  
  Volume 282 Issue Pages 113-132  
  Keywords Activity cycle, Pyrite composition, Roll front uranium deposits, S isotope and trace element fractionation  
  Abstract Complex pyrite textures associated with large changes in isotopic and trace element compositions are routinely assumed to be indicative of multi-faceted processes involving multiple fluid and sulfur sources. We propose that the features of ore-stage pyrite from roll front deposits across the world, revealed in exquisite detail via high-resolution trace element mapping by LA-ICP-MS, reflect the dynamic internal evolution of the biogeochemical processes responsible for sulfate reduction, rather than externally driven changes in fluid or sulfur sources through time. Upon percolation of oxidizing fluids into the reduced host-sandstones, roll front systems become self-organized, with a systematic reset of their activity cycle after each translation stage of the redox interface down dip of the aquifer. Dominantly reducing conditions at the redox interface favor the formation of biogenic framboidal pyrite (δ34S from −30.5 to −12.5‰) by bacterial sulfate reduction and the genesis of the U mineralization. As the oxidation front advances, oxidation of reduced sulfur minerals induces an increased supply of sulfate and metals in solution to the bacterial sulfate reduction zone that has similarly advanced down the flow gradient. Hence, this stage is marked by increased rates of the bacterial sulfate reduction associated with the crystallization of variably As-Co-Ni-Mo-enriched concentric pyrite (up to 10,000′s of ppm total trace contents) with moderately negative δ34S values (from −13.7 to −7.5‰). A final stage of pyrite cement with low trace element contents and heavier δ34S signature (from −6.9 to +18.8‰) marks the end of the roll front activity cycle and the transition from an open to a predominantly closed system behavior (negligible advection of fresh sulfate). Blocky pyrite cement is formed using the remaining sulfate, which now becomes quickly heavy according to a Rayleigh isotope fractionation process. This ends the cycle by depleting the nutrient supplies for the sulfate-reducing bacteria and cementing pore spaces within the host sandstone, effectively restricting fluid infiltration. This internally-driven roll front activity cycle results in systematic, large S isotope and trace element fractionation. Ultimately, the long-time evolution of the basin and fluid sources control the metal endowment and evolution of the system; these events, however, are unlikely to be preserved by the roll front, as a direct result of its hydrodynamic nature.  
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  ISSN 0016-7037 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ bonnetti_large_2020 Serial 185  
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Author Gil-Márquez, J.M.; Sültenfuß, J.; Andreo, B.; Mudarra, M. url  openurl
  Title Groundwater dating tools (3H, 3He, 4He, CFC-12, SF6) coupled with hydrochemistry to evaluate the hydrogeological functioning of complex evaporite-karst settings Type Journal Article
  Year 2020 Publication Journal of Hydrology Abbreviated Journal  
  Volume 580 Issue Pages 124263  
  Keywords Groundwater dating, Evaporite karst, Brine spring, Free-shape models  
  Abstract The hydrogeological functioning of four different areas in a complex evaporite-karst unit of predominantly aquitard behavior in S Spain was investigated. Environmental dating tracers (3H, 3He, 4He, CFC-12, SF6) and hydrochemical data were determined from spring samples to identify and characterize groundwater flow components of different residence times in the media. Results show a general geochemical evolution pattern, from higher (recharge areas) to lower positions (discharge areas), in which mineralization rises as well as the value of the rCl−/SO42−, evidencing longer water-rock interaction. Ne values show degassing of most of the samples, favored by the high salinity of groundwater and the development of karstification so that the concentration of all the considered gases were corrected according to the difference between the theoretical and the measured Ne. The presence of modern groundwater in every sample was proved by the detection of 3H and CFC-12. At the opposite, the higher amount of radiogenic 4He in most samples also indicates that they have an old component. The 3H/3He dating method does not give reliable ages as a consequence of degassing and the large uncertainty of the 3He/4He ratios of the sources for the radiogenic Helium. The large SF6 concentrations suggest terrigenic production related to halite and dolomite. Binary Mixing and Free Shape Models were created based on 3H and CFC-12 data to interpret the age distribution of the samples. Two parameters (GA50 and >70%) were proposed as an indicator of that distribution, as they provide further information than the mean age. Particularly, GA50 is derived from the median groundwater age and is presented as a new way of interpreting mixed groundwater age data. A greater fraction of old groundwater (3H and CFC-12 free) was identified in discharge areas, while the proportion and estimated infiltration date of the younger fractions in recharge areas were higher and more recent, respectively. The application of different approaches has been useful to corroborate previous theoretical conceptual model proposed for the study area and to test the applicability of the used environmental tracer in dating brine groundwater and karst springs.  
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  ISSN 0022-1694 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Gilmarquez2020124263 Serial 213  
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Author Sedghi, M.M.; Zhan, H. url  openurl
  Title Semi-analytical solutions of discharge variation of a qanat in an unconfined aquifer subjected to general areal recharge and nearby pumping well discharge Type Journal Article
  Year 2020 Publication Journal of Hydrology Abbreviated Journal  
  Volume 584 Issue Pages 124691  
  Keywords Analytical solution, Laplace domain, Screen segmentation, Qanat, Areal recharge, Constant head  
  Abstract Qanat is a type of drain that extract water from aquifers by gravity. Significant amount of fresh water used in Middle East and other parts of the world are supplied by qanats. Despite their importance, discharge variation of these type of wells received almost no attention. The aim of this research is to obtain a Laplace domain solution of discharge variation of a qanat installed in an anisotropic unconfined aquifer subjected to arbitrary areal recharge and nearby pumping well(s) discharge. A new semi-analytical solution of drawdown is obtained first to implement the effects of arbitrary areal recharge and nearby pumping well(s) using the principle of superposition. Then, the discharge variation solution of the qanat is obtained from the drawdown solution. To establish a constant-head boundary condition at the qanat periphery, the qanat is discretized into several segments. The results of this study are presented in dimensionless discharge-dimensionless time curves. The effects of hydraulic as well as geometric parameters on the discharge variation of the qanat due to arbitrary areal recharge, falling of water table from its initial position and discharge of nearby wells are explored. We also investigate the influences of distance and screen depth and location of the nearby well on the discharge variation of the qanat. The results of this study can be utilized for multiple purposes: 1) to predict discharge of qanat in response to rainfall and nearby pumping well(s); 2) to estimate the aquifer parameters using hydrograph of the qanat; 3) to determine optimal location and pumping pattern of the nearby wells to minimize their influences on the discharge of the qanat; 4) to calculate water budget of aquifers drained by a qanat. The equation presented in this work can also be used to estimate discharge of a horizontal drain installed in cropland subjected to arbitrary irrigation pattern.  
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  ISSN 0022-1694 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Sedghi2020124691 Serial 261  
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