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Author (up) Döll, P.; Krol, M.; Fuhr, D.; Gaiser, T.; Herfort, J.; Höynck, S.; Jaeger, A.; Külls, C.; Mendiondo, E.M.; Printz, A.; others
Title Integrated scenarios of regional development in Ceará and Piauí Type Book Chapter
Year 2003 Publication Global Change and Regional Impacts Abbreviated Journal
Volume Issue Pages 19-41
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Publisher Springer, Berlin, Heidelberg Place of Publication Editor
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Notes Approved no
Call Number THL @ christoph.kuells @ Doll2003integrated Serial 39
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Author (up) Doulgeris, C.; Tziritis, E.; Pisinaras, V.; Panagopoulos, A.; Külls, C.
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 (up) Dutova, E.M.; Nikitenkov, A.N.; Pokrovskiy, V.D.; Banks, D.; Frengstad, B.S.; Parnachev, V.P.
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 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 (up) Edmunds, W.M.; Shand, P.; Hart, P.; Ward, R.S.
Title The natural (baseline) quality of groundwater: a UK pilot study Type Journal Article
Year 2003 Publication Science of The Total Environment Abbreviated Journal
Volume 310 Issue 1 Pages 25-35
Keywords Baseline quality, Groundwater, Hydrogeochemistry, Monitoring, Water Policy
Abstract Knowledge of the natural baseline quality of groundwaters is an essential prerequisite for understanding pollution and for imposing regulatory limits. The natural baseline of groundwaters may show a range of concentrations depending on aquifer mineralogy, facies changes, flow paths and residence time. The geochemical controls on natural concentrations are discussed and an approach to defining baseline concentrations using geochemical and statistical tools is proposed. The approach is illustrated using a flowline from the Chalk aquifer in Berkshire, UK where aerobic and anaerobic sections of the aquifer are separately considered. The baseline concentrations for some elements are close to atmospheric values whereas others evolve through time-dependent water–rock interaction. Certain solutes (K, NH4+), often considered contaminants, reach naturally high concentrations due to geochemical controls; transition metal concentrations are generally low, although their concentrations may be modified by redox controls. It is recommended that the baseline approach be incorporated into future management strategies, notably monitoring.
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ISSN 0048-9697 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ edmunds_natural_2003 Serial 166
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Author (up) Eliades, M.; Bruggeman, A.; Djuma, H.; Christofi, C.; Kuells, C.
Title Quantifying Evapotranspiration and Drainage Losses in a Semi-Arid Nectarine (Prunus persica var. nucipersica) Field with a Dynamic Crop Coefficient (Kc) Derived from Leaf Area Index Measurements Type Journal Article
Year 2022 Publication Water Abbreviated Journal
Volume 14 Issue 5 Pages
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Abstract Quantifying evapotranspiration and drainage losses is essential for improving irrigation efficiency. The FAO-56 is the most popular method for computing crop evapotranspiration. There is, however, a need for locally derived crop coefficients (Kc) with a high temporal resolution to reduce errors in the water balance. The aim of this paper is to introduce a dynamic Kc approach, based on Leaf Area Index (LAI) observations, for improving water balance computations. Soil moisture and meteorological data were collected in a terraced nectarine (Prunus persica var. nucipersica) orchard in Cyprus, from 22 March 2019 to 18 November 2021. The Kc was derived as a function of the canopy cover fraction (c), from biweekly in situ LAI measurements. The use of a dynamic Kc resulted in Kc estimates with a bias of 17 mm and a mean absolute error of 0.8 mm. Evapotranspiration (ET) ranged from 41% of the rainfall (P) and irrigation (I) in the wet year (2019) to 57% of P + I in the dry year (2021). Drainage losses from irrigation (DR_I) were 44% of the total irrigation. The irrigation efficiency in the nectarine field could be improved by reducing irrigation amounts and increasing the irrigation frequency. Future studies should focus on improving the dynamic Kc approach by linking LAI field observations with remote sensing observations and by adding ground cover observations.
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ISSN 2073-4441 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Marinos2022 Serial 82
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