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Author Stone, A.E.C.; Edmunds, W.M. url  openurl
  Title Naturally-high nitrate in unsaturated zone sand dunes above the Stampriet Basin, Namibia Type Journal Article
  Year 2014 Publication Journal of Arid Environments Abbreviated Journal  
  Volume 105 Issue Pages 41-51  
  Keywords Kalahari, Namibia, Nitrate in the unsaturated zone, Stampriet Basin, Transboundary basin, Unsaturated zone recharge  
  Abstract (up) Elevated groundwater nitrate levels are common in drylands, often in excess of WHO guidelines, with concern for human and animal health. In light of recent attempts to identify nitrate sources in the Kalahari this paper presents the first unsaturated zone (USZ) nitrate profiles and recharge rate estimates for the important transboundary Stampriet Basin, alongside the first rainfall chemistry records. Elevated subsurface nitrate reaches 100–250 and 250–525 mg/L NO3–N, with NO3–N/Cl of 4–12, indicating input above evapotranspiration. Chloride mass balance recharge rates range from 4 to 27 mm/y, indicating a vertical movement of these nitrate pulses toward the water table over multi-decadal timescales. These profiles are sampled from dune crests, away from high concentrations of animals and without termite mounds. Given low-density animal grazing is unlikely to contribute consistent spot-scale nitrate over decades, these profiles give an initial estimate of naturally-produced concentrations. This insight is important for the management of the Stampriet Basin and wider Kalahari groundwater. This study expands our knowledge about elevated nitrate in dryland USZs, demonstrating that it can occur as pulses, probably in response to transient vegetation cover and that it is not limited to long-residence time USZs with very limited downward moisture flux (recharge).  
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  ISSN 0140-1963 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Stone201441 Serial 279  
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Author Heaton, T.H.E. url  openurl
  Title Sources of the nitrate in phreatic groundwater in the western Kalahari Type Journal Article
  Year 1984 Publication Journal of Hydrology Abbreviated Journal  
  Volume 67 Issue 1 Pages 249-259  
  Keywords  
  Abstract (up) Elevated levels of nitrate occur in phreatic groundwater in the western Kalahari, Namibia. Nitrate in water containing 0.4–3.1 meq NO−3l−1, of widespread occurrence, has δ15N values in the range +4.9 to +8.0‰, suggesting natural derivation from the soil. The sporadic occurrence of very high levels of nitrate (> 4 meq NO−3l−1), which has δ15N between +9.3 to +18.7‰, reflects pollution derived from animal waste. The importance of considering the possible isotopic effects of denitrification, and the significance of leaching in the nitrogen budget of the Kalahari soil, are also discussed.  
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  Series Volume Series Issue Edition  
  ISSN 0022-1694 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Heaton1984249 Serial 278  
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Author Martínez-Santos, P.; Martínez-Alfaro, P.E. url  openurl
  Title A priori mapping of historical water-supply galleries based on archive records and sparse material remains. An application to the Amaniel qanat (Madrid, Spain) Type Journal Article
  Year 2014 Publication Journal of Cultural Heritage Abbreviated Journal  
  Volume 15 Issue 6 Pages 656-664  
  Keywords Hydraulic heritage, Qanat, Groundwater, Foggara, Water-supply, Amaniel, Madrid  
  Abstract (up) Engineering heritage refers to a broad variety of items of social, economic, aesthetic or historic relevance, including roads, dams, buildings and supply networks. Due to their utilitarian nature, their heritage value is often overlooked. This occurs even with those infrastructures that have played an essential role in underpinning the daily existence of entire civilizations. Underground water-supply networks provide an excellent example. Although there are exceptions, water networks tend to be functional in design, rather than monumental. Moreover, they present intricate linear layouts that often span several kilometres. This means they are costly to maintain once their operational life is over, and that they are prone to abandonment and destruction. Devising a priori protection strategies is important to preserve these valuable cultural assets. The following pages present a method to map linear structures based on archive records and sparse material remains. The method is illustrated through its application to the Amaniel qanat, a water-supply gallery built in Madrid, Spain, in the early 17th Century. An appraisal of the known remains was carried out first, leading to an inventory of galleries, shafts, shaft caps and deposits. This was followed by a thorough survey of over one thousand handwritten manuscripts, including physical descriptions of the aqueduct, budget accounts or water metering campaigns, among other documents. Known remains and written evidence were matched against original and auxiliary maps to reconstruct the itinerary of the aqueduct. This led to the identification of sectors where it is still possible to find remains in good condition. Thus, a priori mapping is advocated a valuable technique to locate and preserve these remains, as well as to devise non-invasive surveys and establish heritage protection zones.  
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  Series Volume Series Issue Edition  
  ISSN 1296-2074 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Martinezsantos2014656 Serial 270  
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Author Mühr-Ebert, E.L.; Wagner, F.; Walther, C. url  openurl
  Title Speciation of uranium: Compilation of a thermodynamic database and its experimental evaluation using different analytical techniques Type Journal Article
  Year 2019 Publication Applied Geochemistry Abbreviated Journal  
  Volume 100 Issue Pages 213-222  
  Keywords  
  Abstract (up) Environmental hazards are caused by uranium mining legacies and enhanced radioactivity in utilized groundwater and surface water resources. Knowledge of uranium speciation in these waters is essential for predicting radionuclide migration and for installing effective water purification technology. The validity of the thermodynamic data for the environmental media affected by uranium mining legacies is of utmost importance. Therefore, a comprehensive and consistent database was established according to current knowledge. The uranium data included in the database is based on the NEA TDB (Guillaumont et al., 2003) and is modified or supplemented as necessary e.g. for calcium and magnesium uranyl carbonates. The specific ion interaction theory (Brönsted, 1922) is used to estimate activity constants, which is sufficient for the considered low ionic strengths. The success of this approach was evaluated by comparative experimental investigations and model calculations (PHREEQC (Parkhurst and Appelo, 1999)) for several model systems. The waters differ in pH (2.7–9.8), uranium concentration (10−9-10−4 mol/L) and ionic strength (0.002–0.2 mol/L). We used chemical extraction experiments, ESI-Orbitrap-MS and time-resolved laser-induced fluorescence spectroscopy (TRLFS) to measure the uranium speciation. The latter method is nonintrusive and therefore does not change the chemical composition of the investigated waters. This is very important, because any change of the system under study may also change the speciation.  
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  ISSN 0883-2927 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ muhr-ebert_speciation_2019 Serial 142  
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Author Tariq, A.; Beni, L.H.; Ali, S.; Adnan, S.; Hatamleh, W.A. url  openurl
  Title An effective geospatial-based flash flood susceptibility assessment with hydrogeomorphic responses on groundwater recharge Type Journal Article
  Year 2023 Publication Groundwater for Sustainable Development Abbreviated Journal  
  Volume 23 Issue Pages 100998  
  Keywords Flood hydrology, AHP, Flood susceptibility, FR, Unit stream power, GIS  
  Abstract (up) Floods are one of the most common natural disasters, resulting in the extensive destruction of infrastructure, property, and human life. The destructive potential of a flood depends on numerous factors, including the size of the flood, the rate of flooding, the time it takes for the water to move through a given area, the river’s planform and cross-section geometry, and other similar factors. The present study is a unique analysis of flood mapping that was accomplished with the help of the Analytical Hierarchy Process (AHP), Frequency Ratio (FR), and hydrogeomorphic response to floods by integrating geospatial analysis and unit stream power modeling. The Indus catchment region of Pakistan is where the subject topic is put into practice. According to the hydrologic analysis of the yearly peak discharge, the hydro-station in Gilgit-Baltistan can move boulders measuring up to 0.5 m in height during significant flooding. On the other hand, there will be no change to the geometry of the cross-section throughout 1980–2020 in Gilgit-Baltistan. The flood susceptibility map is constructed using data from twelve influencing parameters, including elevation, proximity to the drainage network, slope, drainage density, geomorphology, rainfall, the curvature of the topography, flow accumulation, geology, land use, Topographic Wetness Index (TWI), and Stream Power Index (SPI). The area under the curve (AUC) approach, which demonstrates a substantial degree of accuracy (85% and 83%), is utilized to evaluate the effectiveness of the AHP and FR. The current study fills the gaps between the geospatial approach and the hydrogeomorphic assessment of flood to determine flood susceptibility.  
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  ISSN 2352-801x ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Tariq2023100998 Serial 234  
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Author Ruiz, O.; Thomson, B.; Cerrato, J.M.; Rodriguez-Freire, L. url  openurl
  Title Groundwater restoration following in-situ recovery (ISR) mining of uranium Type Journal Article
  Year 2019 Publication Applied Geochemistry Abbreviated Journal  
  Volume 109 Issue Pages 104418  
  Keywords Aquifer stabilization, Ground water restoration, In-situ leach mining, In-situ recovery, Uranium  
  Abstract (up) From 1950 through the early 1980’s New Mexico accounted for roughly half of domestic uranium (U) production for the nuclear power industry and the nation’s weapon programs. Increased interest in nuclear energy has led to proposals for renewed development using both underground mining and uranium in situ recovery (ISR). When feasible, ISR greatly reduces waste generated by the mining and milling processes, however, the ability to restore ground water to acceptable quality after ISR ends is uncertain. This research investigated two methods of stabilizing an aquifer following ISR. Batch and column studies were performed to evaluate chemical and biological methods of stabilization. Columns packed with ore were first leached with an aerated NaHCO3 ground water solution to simulate ISR. Constituents present at elevated concentrations after leaching included molybdenum (Mo), selenium (Se), U, and vanadium (V). Chemical stabilization was studied by passing a phosphate (PO43-) amended solution through the ore to achieve passivation of mineral surfaces by P precipitates. Microbial stabilization was studied by passing a lactate solution through the ore to stimulate growth of anaerobic metal- and sulfate-reducing organisms to reduce U and other elements to less soluble phases. Analyses of the solids from the columns after completion of these experiments by X-ray photo electron spectroscopy (XPS) identified phosphate on samples near the column inlet of the chemically stabilized columns. Microbial populations were characterized by Illumina DNA sequencing and confirmed the presence of metal- and sulfate-reducing organisms. Neither chemical nor microbial stabilization method achieved contaminant immobilization, which is believed due to limited mixing of the stabilization solutions with the contaminated leach solutions. These results emphasize that ground water hydrodynamics, especially mixing, must be considered in aquifer restoration of soluble constituents.  
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  ISSN 0883-2927 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ ruiz_groundwater_2019 Serial 153  
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Author Dutova, E.M.; Nikitenkov, A.N.; Pokrovskiy, V.D.; Banks, D.; Frengstad, B.S.; Parnachev, V.P. url  openurl
  Title Modelling of the dissolution and reprecipitation of uranium under oxidising conditions in the zone of shallow groundwater circulation Type Journal Article
  Year 2017 Publication Journal of Environmental Radioactivity Abbreviated Journal  
  Volume 178-179 Issue Pages 63-76  
  Keywords Groundwater, Hydrochemical modelling, Mineralisation, Natural uranium, Ore, Solubility  
  Abstract (up) Generic hydrochemical modelling of a grantoid-groundwater system, using the Russian software “HydroGeo”, has been carried out with an emphasis on simulating the accumulation of uranium in the aqueous phase. The baseline model run simulates shallow granitoid aquifers (U content 5 ppm) under conditions broadly representative of southern Norway and southwestern Siberia: i.e. temperature 10 °C, equilibrated with a soil gas partial CO2 pressure (PCO2, open system) of 10−2.5 atm. and a mildly oxidising redox environment (Eh = +50 mV). Modelling indicates that aqueous uranium accumulates in parallel with total dissolved solids (or groundwater mineralisation M – regarded as an indicator of degree of hydrochemical evolution), accumulating most rapidly when M = 550–1000 mg L−1. Accumulation slows at the onset of saturation and precipitation of secondary uranium minerals at M = c. 1000 mg L−1 (which, under baseline modelling conditions, also corresponds approximately to calcite saturation and transition to Na-HCO3 hydrofacies). The secondary minerals are typically “black” uranium oxides of mixed oxidation state (e.g. U3O7 and U4O9). For rock U content of 5–50 ppm, it is possible to generate a wide variety of aqueous uranium concentrations, up to a maximum of just over 1 mg L−1, but with typical concentrations of up to 10 μg L−1 for modest degrees of hydrochemical maturity (as indicated by M). These observations correspond extremely well with real groundwater analyses from the Altai-Sayan region of Russia and Norwegian crystalline bedrock aquifers. The timing (with respect to M) and degree of aqueous uranium accumulation are also sensitive to Eh (greater mobilisation at higher Eh), uranium content of rocks (aqueous concentration increases as rock content increases) and PCO2 (low PCO2 favours higher pH, rapid accumulation of aqueous U and earlier saturation with respect to uranium minerals).  
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  ISSN 0265-931x ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ dutova_modelling_2017 Serial 114  
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Author Hofmann, H.; Pearce, J.K.; Hayes, P.; Golding, S.D.; Hall, N.; Baublys, K.A.; Raiber, M.; Suckow, A. url  openurl
  Title Multi-tracer approach to constrain groundwater flow and geochemical baseline assessments for CO2 sequestration in deep sedimentary basins Type Journal Article
  Year 2023 Publication International Journal of Coal Geology Abbreviated Journal  
  Volume Issue Pages 104438  
  Keywords CO geological storage, Great Artesian Basin, Groundwater chemistry, Isotopic tracer, Surat Basin  
  Abstract (up) Geological storage of gases will be necessary in the push to net zero and the energy transition to reduce carbon emissions to atmosphere. These include CO2 geological storage in suitable sandstone reservoirs. Understanding groundwater flow, connectivity and hydrogeochemical processes in aquifer and storage systems is vital to prevent risk and protect important water resources, such as the Great Artesian Basin. Here, we provide a ‘tool-box’ of geochemical assessment methods to provide information on flow patterns through the basin’s aquifers (changes in chemistry along flow path), stagnant versus flowing conditions (cosmogenic isotopes and noble gases), inter-aquifer connectivity and seal properties (major ions, Sr and stable isotopes), water quality (major ions and metals) and general assessments on residence times of groundwater (cosmogenic isotopes and noble gases). This information can be used with reservoir and groundwater models to inform on possible changes in the above-mentioned processes and serve as input parameters for CO2 injection impact modelling. We demonstrate the use and interpretation on an example of a potential CO2 storage geological sequestration site in the Surat Basin, part of the Great Artesian Basin, and the aquifers that overly the reservoir. The stable water isotopes are depleted compared to average rainfall and most likely indicate greater contributions from monsoonal rain events from the northern monsoonal troughs, where amount and rainout effects lead to the depletion rather than colder recharge climates. This is supported by the modern recharge temperatures from noble gases. Inter-aquifer mixing between the Precipice Sandstone reservoir and the Hutton Sandstone aquifer seems unlikely as the Sr isotope ratios are distinctly different suggesting that the Evergreen Formation is a seal in the locations sampled. Mixing, however, occurs on the edges of the basin, especially in the south-east and east where the Surat Basin transitions into the Clarence-Moreton Basin. Groundwater flow appears to be to the south in the Precipice Sandstone, with a component of flow east to the Clarence-Morton Basin. The cosmogenic isotopes and noble gases strongly indicate very long residence times of groundwater in the central south Precipice Sandstone around a proposed storage site. 14C values below analytical uncertainty, R36Cl ratios at secular equilibrium as well as high He concentrations and high 40Ar/36Ar ratios support the argument that groundwater flow in this area is extremely slow or groundwater is stagnant. The results of this study reflect the geological and hydrogeological complexities of sedimentary basins and that baseline studies, such as this one, are paramount for management strategies.  
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  ISSN 0166-5162 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ hofmann_multi-tracer_2023 Serial 165  
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Author Smedley, P.L.; Bearcock, J.M.; Ward, R.S.; Crewdson, E.; Bowes, M.J.; Darling, W.G.; Smith, A.C. url  openurl
  Title Monitoring of methane in groundwater from the Vale of Pickering, UK: Temporal variability and source discrimination Type Journal Article
  Year 2023 Publication Chemical Geology Abbreviated Journal  
  Volume 636 Issue Pages 121640  
  Keywords Aquifer, Biogenic, Ethane, Hydrocarbons, Methane, Shale gas  
  Abstract (up) Groundwater abstracted from aquifers in the Vale of Pickering, North Yorkshire, UK and monitored over the period 2015–2022, shows evidence of variable but commonly high concentrations of dissolved CH4. Sampled groundwater from the Jurassic organic-rich Kimmeridge Clay Formation (boreholes up to 180 m depth) has concentrations up to 57 mg/L, and concentrations up to 59 mg/L are found in groundwater from underlying confined Corallian Group limestone (borehole depths 50–227 m). The high concentrations are mainly from boreholes in the central parts of the vale. Small concentrations of ethane (C2H6, up to 800 μg/L) have been found in the Kimmeridge Clay and confined Corallian groundwaters, and of propane (C3H8, up to 160 μg/L) in deeper boreholes (110–180 m) from these formations. The concentrations are typically higher in groundwater from the deeper boreholes and vary with hydrostatic pressure, reflecting the pressure control on CH4 solubility. The occurrences contrast with groundwater from shallow Quaternary superficial deposits which have low CH4 concentrations (up to 0.39 mg/L), and with the unconfined and semi-confined sections of the Corallian aquifer (up to 0.7 mg/L) around the margins of the vale. Groundwater from the Quaternary, Kimmeridge Clay formations and to a small extent the confined Corallian aquifer, supports local private-water supplies, that from the peripheral unconfined sections of Corallian also supports public supply for towns and villages across the region. Dissolved methane/ethane (C1/C2) ratios and stable-isotopic compositions (δ13C-CH4, δ2H-CH4 and δ13C-CO2) suggest that the high-CH4 groundwater from both the Kimmeridge Clay and confined Corallian formations derives overwhelmingly from biogenic reactions, the methanogenesis pathway by CO2 reduction. A small minority of groundwater samples shows a more enriched δ13C-CH4 composition (−50 to −44 ‰) which has been interpreted as due to anaerobic or aerobic methylotrophic oxidation in situ or post-sampling oxidation, rather than derivation by a thermogenic route. Few of the existing groundwater sites are proximal to abandoned or disused conventional hydrocarbon wells that exist in the region, and little evidence has been found for an influence on groundwater dissolved gases from these sites. The Vale of Pickering has also been under recent consideration for development of an unconventional hydrocarbon (shale-gas) resource. In this context, the monitoring of dissolved gases has been an important step in establishing the high-CH4 baseline of groundwaters from Jurassic deposits in the region and in apportioning their sources and mechanisms of genesis.  
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  ISSN 0009-2541 ISBN Medium  
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  Call Number THL @ christoph.kuells @ smedley_monitoring_2023 Serial 172  
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Author Tujchneider, O.; Christelis, G.; Gun, J.V. der url  openurl
  Title Towards scientific and methodological innovation in transboundary aquifer resource management Type Journal Article
  Year 2013 Publication Environmental Development Abbreviated Journal  
  Volume 7 Issue Pages 6-16  
  Keywords Communication, Cooperation, Holistic methodological approach, Science, Transboundary aquifer management  
  Abstract (up) Groundwater is both an invaluable and a vulnerable resource. Aquifer resources management, aiming at the responsible exploitation and adequate protection of the groundwater resources, is therefore of key importance and has to be based on sound hydrological, environmental, economic and social principles. Aquifer-wide groundwater projects are carried out to collect the required area-specific information, to understand ongoing processes, to identify the management issues to be addressed and to develop an adequate management strategy and action plan. The quality of the project results depends to a large extent on the science and methodologies adopted in the design and used during the implementation of the projects. In this context, a project was carried out recently to analyse the scientific aspects of—among others—the transboundary aquifer projects within the IW: Portfolio of the Global Environmental Facility (GEF) and to make recommendations for scientific strengthening and innovation. This paper presents the main outcomes of this analysis. In order to accomplish groundwater resources management goals in the case of transboundary aquifers, a balanced joint strategy is needed. Analysis of documentation on completed and on-going transboundary aquifer projects has shown a wide range of scientific activities that contribute positively to the development of such strategies. This analysis has also identified options for increasing the positive impacts of science on strategy development; some of these options have been pioneered already and deserve wider application other ones are relatively new. Important options are: integrating transboundary aquifer resource management in a wider environmental–socio-economical context (holistic approach); exploring causal chains to better understand the processes of change of groundwater resources; using this improved understanding for optimising groundwater assessment and monitoring programmes; and adaptive management. In addition, to obtain maximum benefit of the scientific results there is a general need to promote effective communication at all levels, between the scientific community and policy-/decision makers, as well as with the local community who have a major role to play in the use and conservation of the resources. All of this should be accompanied by the harmonisation of the legal instruments and co-operation agreements between countries and the communities involved. Two case studies, one in South America and one in Southern Africa, are added as examples of the setting and approach of the analysed transboundary aquifer projects.  
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  ISSN 2211-4645 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ tujchneider_towards_2013 Serial 105  
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