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1
Person, Mark. « Groundwater in Geologic Processes ». Eos, Transactions American Geophysical Union 81, no 18 (2000) : 204. http://dx.doi.org/10.1029/00eo00139.
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Bottrell, Simon. « Groundwater in geologic processes ». Geophysical Journal International 145, no 1 (avril 2001) : 316. http://dx.doi.org/10.1111/j.1365-246x.2001.00296.x.
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Rostron, Benjamin J. « Groundwater in Geologic Processes ». Geofluids 9, no 4 (novembre 2009) : 386–87. http://dx.doi.org/10.1111/j.1468-8123.2009.00253.x.
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Hernández-Antonio, A., J. Mahlknecht, C. Tamez-Meléndez, J. Ramos-Leal, A. Ramírez-Orozco, R. Parra, N. Ornelas-Soto et C. J. Eastoe. « Groundwater flow processes and mixing in active volcanic systems : the case of Guadalajara (Mexico) ». Hydrology and Earth System Sciences 19, no 9 (24 septembre 2015) : 3937–50. http://dx.doi.org/10.5194/hess-19-3937-2015.
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Abstract. Groundwater chemistry and isotopic data from 40 production wells in the Atemajac and Toluquilla valleys, located in and around the Guadalajara metropolitan area, were determined to develop a conceptual model of groundwater flow processes and mixing. Stable water isotopes (δ2H, δ18O) were used to trace hydrological processes and tritium (3H) to evaluate the relative contribution of modern water in samples. Multivariate analysis including cluster analysis and principal component analysis were used to elucidate distribution patterns of constituents and factors controlling groundwater chemistry. Based on this analysis, groundwater was classified into four groups: cold groundwater, hydrothermal groundwater, polluted groundwater and mixed groundwater. Cold groundwater is characterized by low temperature, salinity, and Cl and Na concentrations and is predominantly of Na-HCO3-type. It originates as recharge at "La Primavera" caldera and is found predominantly in wells in the upper Atemajac Valley. Hydrothermal groundwater is characterized by high salinity, temperature, Cl, Na and HCO3, and the presence of minor elements such as Li, Mn and F. It is a mixed-HCO3 type found in wells from Toluquilla Valley and represents regional flow circulation through basaltic and andesitic rocks. Polluted groundwater is characterized by elevated nitrate and sulfate concentrations and is usually derived from urban water cycling and subordinately from agricultural return flow. Mixed groundwaters between cold and hydrothermal components are predominantly found in the lower Atemajac Valley. Twenty-seven groundwater samples contain at least a small fraction of modern water. The application of a multivariate mixing model allowed the mixing proportions of hydrothermal fluids, polluted waters and cold groundwater in sampled water to be evaluated. This study will help local water authorities to identify and dimension groundwater contamination, and act accordingly. It may be broadly applicable to other active volcanic systems on Earth.
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Hernández-Antonio, A., J. Mahlknecht, C. Tamez-Meléndez, J. Ramos-Leal, A. Ramírez-Orozco, R. Parra, N. Ornelas-Soto et C. J. Eastoe. « Groundwater flow processes and mixing in active volcanic systems : the case of Guadalajara (Mexico) ». Hydrology and Earth System Sciences Discussions 12, no 2 (3 février 2015) : 1599–631. http://dx.doi.org/10.5194/hessd-12-1599-2015.
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Abstract. Groundwater chemistry and isotopic data from 40 production wells in the Atemajac and Toluquilla Valleys, located in and around the Guadalajara metropolitan area, were determined to develop a conceptual model of groundwater flow processes and mixing. Multivariate analysis including cluster analysis and principal component analysis were used to elucidate distribution patterns of constituents and factors controlling groundwater chemistry. Based on this analysis, groundwater was classified into four groups: cold groundwater, hydrothermal water, polluted groundwater and mixed groundwater. Cold groundwater is characterized by low temperature, salinity, and Cl and Na concentrations and is predominantly of Na-HCO3 type. It originates as recharge at Primavera caldera and is found predominantly in wells in the upper Atemajac Valley. Hydrothermal water is characterized by high salinity, temperature, Cl, Na, HCO3, and the presence of minor elements such as Li, Mn and F. It is a mixed HCO3 type found in wells from Toluquilla Valley and represents regional flow circulation through basaltic and andesitic rocks. Polluted groundwater is characterized by elevated nitrate and sulfate concentrations and is usually derived from urban water cycling and subordinately from agricultural practices. Mixed groundwaters between cold and hydrothermal components are predominantly found in the lower Atemajac Valley. Tritium method elucidated that practically all of the sampled groundwater contains at least a small fraction of modern water. The multivariate mixing model M3 indicates that the proportion of hydrothermal fluids in sampled well water is between 13 (local groundwater) and 87% (hydrothermal water), and the proportion of polluted water in wells ranges from 0 to 63%. This study may help local water authorities to identify and quantify groundwater contamination and act accordingly.
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Foster, S. S. D., et P. J. Chilton. « Groundwater : the processes and global significance of aquifer degradation ». Philosophical Transactions of the Royal Society of London. Series B : Biological Sciences 358, no 1440 (5 novembre 2003) : 1957–72. http://dx.doi.org/10.1098/rstb.2003.1380.
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The exploitation of groundwater resources for human use dates from the earliest civilizations, but massive resource development has been largely restricted to the past 50 years. Although global in scope, the emphasis of this paper is on groundwater–based economies in a developing nation context, where accelerated resource development has brought major social and economic benefits over the past 20 years. This results from groundwater's significant role in urban water supply and in rural livelihoods, including irrigated agriculture. However, little of the economic benefit of resource development has been reinvested in groundwater management, and concerns about aquifer degradation and resource sustainability began to arise. A general review, for a broad–based audience, is given of the mechanisms and significance of three semi–independent facets of aquifer degradation. These are (i) depletion of aquifer storage and its effects on groundwater availability, terrestrial and aquatic ecosystems; (ii) groundwater salinization arising from various different processes of induced hydraulic disturbance and soil fractionation; and (iii) vulnerability of aquifers to pollution from land–use and effluent discharge practices related to both urban development and agricultural intensification. Globally, data with which to assess the status of aquifer degradation are of questionable reliability, inadequate coverage and poor compilation. Recourse has to be made to ‘type examples’ and assumptions about the extension of similar hydrogeological settings likely to be experiencing similar conditions of groundwater demand and subsurface contaminant load. It is concluded that (i) aquifer degradation is much more than a localized problem because the sustainability of the resource base for much of the rapid socio–economic development of the second half of the twentieth century is threatened on quite a widespread geographical basis; and (ii) major (and long overdue) investments in groundwater resource and quality protection are urgently needed. These investments include appropriate institutional provisions, demand–side management, supply–side enhancement and pollution control.
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Listiyani R.A., T. « HYDROCHEMISTRY OF GROUNDWATER IN GEYER, GROBOGAN PROVINCE, CENTRAL JAVA ». KURVATEK 1, no 2 (23 mai 2017) : 13–19. http://dx.doi.org/10.33579/krvtk.v1i2.230.
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The demand of clean water as well as good quality of drinking water in research area puss the author for knowing about groundwater quality in research area. The aim of the research is to understand the hydrochemistry of groundwater in study area, includinghydrochemical processes and the influence of minerals or rocks to groundwater quality. The methods in the research are groundwater and rocks sampling, petrography and also groundwater’s chemical analysis.Result of this study shows that groundwater quality in Geyer area is influenced by minerals and rocks in that place with dissolution and ions exchange would be important processes. Minerals which composed rocks are dominated by calcareous and clay minerals. These minerals supply chemical components such as Ca2+, Mg2+, Na+, Cl-, carbonate and bicarbonate to groundwater. Key words: hydrochemistry, groundwater, hydrochemical process, major ion.
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van Sambeek, M. H. G., H. G. M. Eggenkamp et M. J. M. Vissers. « The groundwater quality of Aruba, Bonaire and Curaçao : a hydrogeochemical study ». Netherlands Journal of Geosciences - Geologie en Mijnbouw 79, no 4 (décembre 2000) : 459–66. http://dx.doi.org/10.1017/s0016774600021958.
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AbstractThe Groundwater resources on the Caribbean Islands of Aruba, Bonaire and Curaçao are limited and of poor quality. The groundwater of the islands is brackish, due to both seawater mixing and the semi-arid climate of the islands. Two hundred and thirty water samples were collected to relate chemical variations in the groundwater of the three islands to the underlying differences in geology, and to define the natural versus anthropogenic influences. Both the chemical and isotopic (δ180, δD, and δ37Cl) compositions of samples were determined.Several geochemical processes are recognised in the chemistry of the groundwater samples. The most important processes are calcite dissolution, cation exchange, silicate weathering and potassium fixation. In (sub)urban areas anthropogenic influences affect the groundwater quality: high nitrate concentrations were measured. Infiltrating domestic and agricultural (waste)water replenishes the aquifer, and has a desalinization effect on the groundwater quality. This phenomenon is primarily seen on Curaçao, the most populated island.Oxygen and hydrogen isotopie compositions of groundwaters from Curaçao and Bonaire show that the samples are either meteoric water, or are affected by evaporation or seawater mixing. No distinction could be made between the last two processes. Only a few samples were measured for the Cl-isotope composition; all showed that no physical processes have taken place.
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Bekins, Barbara. « Preface - Groundwater and microbial processes ». Hydrogeology Journal 8, no 1 (13 mars 2000) : 2–3. http://dx.doi.org/10.1007/s100400050002.
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Trembàczowski, Andrzej. « Sulphur and Oxygen Isotopes Behaviour in Sulphates of Atmospheric Ground water System Observations and Model ». Hydrology Research 22, no 1 (1 février 1991) : 49–66. http://dx.doi.org/10.2166/nh.1991.0004.
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Comparison of sulphate concentrations in groundwaters and atmospheric precipitation suggests that about 30 % of groundwater sulphate may be of atmospheric origin. Another source of sulphate ion is the oxidation of sulphur compounds by microorganisms in the soil or in the aquifer. The sulphates of atmospheric and biogenic origin are mixed in the soil and subsequently the mixture gets into the groundwater. The ð34S data suggest, that ð34S of biogenic sulphates is the same as that of atmospheric sulphates. Processes such as: the assimilation of sulphates by plants, their decay and oxidation of organic compounds do not change the ð34S significantly. Significant differences between ð18O values of sulphates of atmospheric and biogenic origin, which are created by microbiological sulphur-oxidizing processes, may be useful for interpretation of the processes in the groundwater system.
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Haria, A. H., et P. Shand. « Evidence for deep sub-surface flow routing in forested upland Wales : implications for contaminant transport and stream flow generation ». Hydrology and Earth System Sciences 8, no 3 (30 juin 2004) : 334–44. http://dx.doi.org/10.5194/hess-8-334-2004.
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Abstract. Upland streamflow generation has traditionally been modelled as a simple rainfall-runoff mechanism. However, recent hydrochemical studies conducted in upland Wales have highlighted the potentially important role of bedrock groundwater in streamflow generation processes. To investigate these processes, a detailed and novel field study was established in the riparian zone and lower hillslopes of the Hafren catchment at Plynlimon, mid-Wales. Results from this study showed groundwater near the river behaving in a complex and most likely confined manner within depth-specific horizons. Rapid responses to rainfall in all boreholes at the study site indicated rapid recharge pathways further upslope. The different flow pathways and travel times influenced the chemical character of groundwaters with depth. Groundwaters were shown to discharge into the stream from the fractured bedrock. A lateral rapid flow horizon was also identified as a fast flow pathway immediately below the soils. This highlighted a mechanism whereby rising groundwater may pick up chemical constituents from the lower soils and transfer them quickly to the stream channel. Restrictions in this horizon resulted in groundwater upwelling into the soils at some locations indicating soil water to be sourced from both rising groundwater and rainfall. The role of bedrock groundwater in upland streamflow generation is far more complicated than previously considered, particularly with respect to residence times and flow pathways. Hence, water quality models in upland catchments that do not take account of the bedrock geology and the groundwater interactions therein will be seriously flawed. Keywords: bedrock, groundwater, Hafren, hillslope hydrology, Plynlimon, recharge, soil water, streamflow generation
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Liu, Ji Lai, Tian Ming Huang et Jie Li. « Groundwater Recharge Environments and Hydrogeochemical Evolution in Beijing, China : Multi-Tracer Approach ». Advanced Materials Research 518-523 (mai 2012) : 3647–51. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.3647.
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The groundwater recharge environments and hydrogeochemical characteristics in Beijing were investigated using a combination of chemical indicators, stable isotopes, and radiocarbon dating. There are two distinct zones for those groundwaters: modern water (1000 a) are depleted, which implies that the palaeowaters were recharged in relatively cold climate. The TDS for all groundwater samples range from 312 to 914 mg/L. Groundwaters are supersaturated with respect to calcite and the δ13C value is stable (around -13‰), which suggests dissolution of calcite is limited. Dissolution of halite, sulfate and carbonate and exchange of cations are main processes of water chemistry. The results have important implications for groundwater management in Beijing, where a certain proportion of the unrenewable water has been mined.
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Shevchenko, O., et V. Dolin. « GROUNDWATER SELF-CLEARING FROM 90SR WITHIN BACKGROUND AREA AND OWING TO ARTIFICIAL CONTAMINATION ». Visnyk of Taras Shevchenko National University of Kyiv. Geology, no 3 (82) (2018) : 100–106. http://dx.doi.org/10.17721/1728-2713.82.13.
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The main idea of the presented results is the determination of spatial-temporal regularities of 90Sr content in groundwaters within Chornobyl Exclusion Zone. Utilization of formal kinetic regularities (of I order for irreversible process) for monitoring data analyses has been substantiated. Rate constants of groundwater self-clearing from 90Sr in dependence of type of contamination are calculated by iteration method. Graphic interpretation of data has been realized using package for analysis of Microsoft Excel and Statistica software. Self-clearing of groundwaters is carried out owing to three main processes: sorption as function of water containing medium dispercity, dispersion due to water exchange, concentration dilution (dissolving) of radionuclides in specified volume, and physical decay. considered Self-clearing is considered to be an important element both for the security and vulnerability of groundwaters. Data on 90Sr content in groundwater of background areas, in affected zone of radioactive waste storage, zone of groundwater nutrition from cooling pond of Chornobyl NPP, spots of primarily radioactive contamination, and of groundwater secondary contamination owing to well drilling are discussed. Rate constants for groundwater self-clearing from 90Sr are calculated from experimental data both for non-stationary (rapid) and stationary (slow) processes. The “half-decontamination” period (in analogy to half-life) is less than 0.5 year. The rate constant for unstable process two times, and for established one time exceeds the decay constant. The rates of groundwater self-clearing from strontium-90 owing to water exchange and geochemically immobilization are determined. The equilibrium of sorption-desorption within water saturated zone is generally depended on the rate of water exchange and radionuclides concentration in upper stream, i.e. from concentration gradient.
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Burger, F., et A. Čelková. « Salinity and sodicity hazard in water flow processes in the soil ». Plant, Soil and Environment 49, No. 7 (10 décembre 2011) : 314–20. http://dx.doi.org/10.17221/4130-pse.
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This paper presents the results of the distribution of salinity characteristics (electrical conductivity and sodium adsorption ratio) of groundwater, and based on the results, it reports the evaluation of the salinity and sodicity hazards in the fluctuation processes of shallow mineralised groundwater, or in the processes if such groundwater is used for irrigation. The issue was studied for the soil-water environment in the south-east of the Danube Lowlands for the period 1991 to 1994. The measured data and data taken from archives were processed in the form of graphical attachments (appendixes, supplements, graphical documentation) – maps, by means of the kriging interpolation method. Groundwater in the area in question is classified as highly mineralised with a high hazard of salinisation of the subsurface soil environment. The average annual values of the electrical conductivity of groundwater ranged from 600 to 2100 µS/cm in the examined period. The sodium adsorption ratio values ranged from 1.7 to 22.0 and indicate low, medium to high sodium salinisation of the environment due to groundwater. The distribution of electrical conductivity and sodium adsorption ratio on the regional scale can serve as a reference basis for the evaluation of changes in the groundwater salinity after 1994.
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Lam, A., D. Karssenberg, B. J. J. M. van den Hurk et M. F. P. Bierkens. « Spatial and temporal connections in groundwater contribution to evaporation ». Hydrology and Earth System Sciences Discussions 8, no 1 (1 février 2011) : 1541–68. http://dx.doi.org/10.5194/hessd-8-1541-2011.
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Abstract. In climate models, lateral terrestrial water fluxes are usually neglected. We estimated the contribution of vertical and lateral groundwater fluxes to the land surface water budget at a subcontinental scale, by modelling convergence of groundwater and surfacewater fluxes. We present a hydrological model of the entire Danube Basin at 5 km resolution, and use it to show the importance of groundwater for the surface climate. The contribution of groundwater to evaporation is significant, and can be upwards of 30% in summer. We show that this contribution is local by presenting the groundwater travel times and the magnitude of groundwater convergence. Throughout the Danube Basin the lateral fluxes of groundwater are negligible when modelling at this scale and resolution. Also, it is shown that the contribution of groundwater to evaporation has important temporal characteristics. An experiment with the same model shows that a wet episode influences groundwaters contribution to summer evaporation for several years afterwards. This indicates that modelling groundwater flow has the potential to augment the multi-year memory of climate models.
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Guggenmos, M. R., B. M. Jackson et C. J. Daughney. « Investigation of groundwater-surface water interaction using hydrochemical sampling with high temporal resolution, Mangatarere catchment, New Zealand ». Hydrology and Earth System Sciences Discussions 8, no 6 (21 novembre 2011) : 10225–73. http://dx.doi.org/10.5194/hessd-8-10225-2011.
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Abstract. The interaction between groundwater and surface water is dynamic and is known to show considerable spatial and temporal variability. Generally hydrological studies that investigate this interaction are conducted at weekly to yearly timescales and inadvertently lose information contained at the neglected shorter timescales. This paper utilises high resolution physical and chemical measurements to investigate the groundwater and surface water interactions of the small temperate Mangatarere Stream in New Zealand. Continuous electrical conductivity, water temperature and stage measurements were obtained at two surface water gauging stations and one groundwater station, along with one week of intensive hydrochemical grab sampling. A second groundwater gauging station provided limited additional data. The downstream reach of the Mangatarere Stream received significant base flow from neighbouring groundwaters which provided cool Na+-Cl− type waters, high in TDS and NO−3 concentrations. This reach also lost water to underlying groundwaters during an extended dry period when precipitation and regional groundwater stage were low. The upstream groundwater station received recharge primarily from precipitation as indicated by a Na+-Cl−-NO−3 signature, the result of precipitation passage through the soil-water zone. However, river recharge was also provided to the upstream groundwater station as indicated by the transferral of a diurnal water temperature pattern and dilute Na+-Ca2+-Mg2+-HCO3−-Cl− signature. Results obtained from the Mangatarere catchment confirm the temporal complexities of groundwater and surface water interaction and highlight the benefits of multiple investigative approaches and the importance of high frequency hydrochemical sampling and monitoring for process understanding.
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Guggenmos, M. R., C. J. Daughney, B. M. Jackson et U. Morgenstern. « Regional-scale identification of groundwater-surface water interaction using hydrochemistry and multivariate statistical methods, Wairarapa Valley, New Zealand ». Hydrology and Earth System Sciences Discussions 8, no 4 (6 juillet 2011) : 6443–87. http://dx.doi.org/10.5194/hessd-8-6443-2011.
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Abstract. Identifying areas of interaction between groundwater and surface water is crucial for effective environmental management, because this interaction is known to influence water quantity and quality. This paper applies hydrochemistry and multivariate statistics to identify locations and mechanisms of groundwater-surface water interaction in the pastorally dominated Wairarapa Valley, New Zealand. Hierarchical Cluster Analysis (HCA) and Principal Components Analysis (PCA) were conducted using site-specific median values of Ca, Mg, Na, K, HCO3, Cl, SO4 and electrical conductivity from 22 surface water sites and 246 groundwater sites. Surface water and groundwater monitoring sites were grouped together in three of the seven clusters identified by HCA, with the inference made that similarities in hydrochemistry indicate groundwater-surface water interaction. PCA indicated that the clusters were largely differentiated by total dissolved solids concentration, redox potential and ratio of major ions. Shallow aerobic groundwaters, located in close proximity to losing reaches of rivers, were grouped with similar Ca-HCO3 type surface waters, indicating potential recharge to aquifers from these river systems. Groundwaters that displayed a rainfall-recharged chemical signature with higher Na relative to Ca, higher Cl relative to HCO3 and an accumulation of NO3 were grouped with neighbouring surface waters, suggesting the provision of groundwater base flow to these river systems and the transfer of this chemical signature from underlying aquifers. The hydrochemical techniques used in this study did not reveal groundwater-surface water interaction in some parts of the study area, specifically where deep anoxic groundwaters, high in total dissolved solids with a distinct Na-Cl signature, showed no apparent link to surface water. The drivers of hydrochemistry inferred from HCA and PCA are consistent with previous measurements of 18O, water age and excess air. Overall, this study has shown that multivariate statistics can be used as a rapid method to identify groundwater-surface water interaction at a regional scale using existing hydrochemical datasets.
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Mavroulidou, M., M. J. Gunn et R. I. Woods. « Numerical modelling of groundwater pumping processes ». Geotechnical Engineering 158, no 2 (avril 2005) : 83–93. http://dx.doi.org/10.1680/geng.158.2.83.61627.
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Mavroulidou, M., M. J. Gunn et R. I. Woods. « Numerical modelling of groundwater pumping processes ». Proceedings of the Institution of Civil Engineers - Geotechnical Engineering 158, no 2 (avril 2005) : 83–93. http://dx.doi.org/10.1680/geng.2005.158.2.83.
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Jackson, R. E. « Groundwater in Geologic Processes, Second Edition ». Environmental and Engineering Geoscience 15, no 1 (1 février 2009) : 48–50. http://dx.doi.org/10.2113/gseegeosci.15.1.48.
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Grindrod, Peter M., et Matthew R. Balme. « Groundwater processes in Hebes Chasma, Mars ». Geophysical Research Letters 37, no 13 (juillet 2010) : n/a. http://dx.doi.org/10.1029/2010gl044122.
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Hobday, D. K., et W. E. Galloway. « Groundwater processes and sedimentary uranium deposits ». Hydrogeology Journal 7, no 1 (18 février 1999) : 127–38. http://dx.doi.org/10.1007/s100400050184.
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Sierikova, Olena, Volodymyr Koloskov et Elena Strelnikova. « The groundwater level changing processes modeling in 2D and 3D formulation ». Acta Periodica Technologica, no 53 (2022) : 36–47. http://dx.doi.org/10.2298/apt2253036s.
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The objective of this study was to develop a mathematical model to determine the tendency of the groundwater level changes under the influence of external factors to prevent environmentally hazardous impacts and emergency situations. Mathematical methods (analytical solution of differential filtration equations involved the computer program Maple) - for creation the groundwater level changes model, methods of ecological and economic assessment and comparative analysis - for the identification of groundwater level impact important factors and groundwater level impact on the environment, balance method - for assessing the groundwater level changes. The mathematical model in 2D formulation works from any value of the initial groundwater level. The value of groundwater level changing at constant evapotranspiration has been obtained, which has been visualized by calculations for limited areas of the Kharkiv territory. Three-dimensional modelling of groundwater level changing in contrast to two-dimensional allows to take into account the dependence of evapotranspiration on the presence of artificial coverings on the soil surface, which are located unevenly and have different filtration coefficients, which causes corresponding groundwater level changes of urban areas. The nature of groundwater level changes under the influence of external factors has been determined. The necessity to create three-dimensional mathematical models to describe groundwater level changes and improve forecasts of their changes have been identified. A three-dimensional mathematical model of urban groundwater level changes, such as atmospheric water infiltration, additional groundwater replenishment, transpiration, evaporation, evapotranspiration, and groundwater abstraction has been developed. The boundary conditions of the three-dimensional mathematical model have been formulated.
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Chen, Jun Jie, Xu Hui Gao, Long Fei Yan et De Guang Xu. « Recent Progress in Monoaromatic Pollutants Removal from Groundwater through Bioremediation ». International Letters of Natural Sciences 34 (février 2015) : 62–69. http://dx.doi.org/10.18052/www.scipress.com/ilns.34.62.
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Monoaromatic pollutants such as benzene, toluene, ethylbenzene and mixture of xylenes are now considered as widespread contaminants of groundwater. In situ bioremediation under natural attenuation or enhanced remediation has been successfully used for removal of organic pollutants, including monoaromatic compounds, from groundwater. Results published indicate that in some sites, intrinsic bioremediation can reduce the monoaromatic compounds content of contaminated water to reach standard levels of potable water. However, engineering bioremediation is faster and more efficient. Also, studies have shown that enhanced anaerobic bioremediation can be applied for many BTEX contaminated groundwaters, as it is simple, applicable and economical. This paper reviews microbiology and metabolism of monoaromatic biodegradation and in situ bioremediation for BTEX removal from groundwater under aerobic and anaerobic conditions. It also discusses the factors affecting and limiting bioremediation processes and interactions between monoaromatic pollutants and other compounds during the remediation processes.
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Chen, Jun Jie, Xu Hui Gao, Long Fei Yan et De Guang Xu. « Recent Progress in Monoaromatic Pollutants Removal from Groundwater through Bioremediation ». International Letters of Natural Sciences 34 (17 février 2015) : 62–69. http://dx.doi.org/10.56431/p-dpda6i.
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Monoaromatic pollutants such as benzene, toluene, ethylbenzene and mixture of xylenes are now considered as widespread contaminants of groundwater. In situ bioremediation under natural attenuation or enhanced remediation has been successfully used for removal of organic pollutants, including monoaromatic compounds, from groundwater. Results published indicate that in some sites, intrinsic bioremediation can reduce the monoaromatic compounds content of contaminated water to reach standard levels of potable water. However, engineering bioremediation is faster and more efficient. Also, studies have shown that enhanced anaerobic bioremediation can be applied for many BTEX contaminated groundwaters, as it is simple, applicable and economical. This paper reviews microbiology and metabolism of monoaromatic biodegradation and in situ bioremediation for BTEX removal from groundwater under aerobic and anaerobic conditions. It also discusses the factors affecting and limiting bioremediation processes and interactions between monoaromatic pollutants and other compounds during the remediation processes.
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Lubis, Rachmat Fajar, Yasuo Sakura et Robert Delinom. « Groundwater recharge and discharge processes in the Jakarta groundwater basin, Indonesia ». Hydrogeology Journal 16, no 5 (12 février 2008) : 927–38. http://dx.doi.org/10.1007/s10040-008-0278-1.
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Islam, Md Shajedul, et M. G. Mostafa. « Evaluation of Hydrogeochemical Processes in Groundwater Using Geochemical and Geostatistical Approaches in the Upper Bengal Basin ». Geofluids 2022 (6 avril 2022) : 1–21. http://dx.doi.org/10.1155/2022/9591717.
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Overexploitation of groundwater for irrigation and radical changes of river morphology in the Bengal basin has posed difficulties to sustainable management of this resource. Forty groundwater samples were collected from tube wells of the pre-monsoon and postmonsoon seasons in 2020, and the water parameters were analyzed. The hydrogeochemical studies, bivariate plots, and multivariate techniques were used to evaluate the rock-water interactions, influencing factors, and contamination pathways. The principal component analysis (PCA) was used to extract several directions in the data space and understand the different geochemical processes. Q-mode hierarchical cluster analysis coupled with the post hoc ANOVA test of variance was also used to divide the sampling sites based on the geochemical water facies. The PHREEQC-3v software was used to measure the partial pressure of CO2 in groundwater and elucidate the chemical reactions controlling the water chemistry. Near-neutral pH (7.4) and high EC (813.2 μS/cm), TDS (507.35 mg/L), and total hardness (383.45 mg/L) characterize the groundwaters of the study area. The research revealed that the order of abundance of cations was Ca2+>Mg2+>Na+>K+ and of anions was HCO3−>>Cl->SO42−>NO3->PO43-. The PCA revealed that the chemical properties of the groundwater are derived from rock-water interactions. Hierarchical cluster analysis showed that two distinct groundwater zones were affected by neighboring river flow and irrigation return flow. Several diagrams suggested that the water was mainly of Ca-HCO3 type originating from chemical weathering of rock-forming minerals with advanced water-rock interaction. The analyzed groundwater was supersaturated with calcite and partially saturated with dolomite. As a result, the chemical features of groundwater in the study area were largely dependent on the water-rock interaction, local lithological conditions, and neighboring river morphology. This study can be helpful for the improvement of water resource management, especially for drinking and irrigation purposes.
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Dang, Xianzhang, Maosheng Gao, Zhang Wen, Guohua Hou, Hamza Jakada, Daniel Ayejoto et Qiming Sun. « Saline groundwater evolution in the Luanhe River delta (China) during the Holocene : hydrochemical, isotopic, and sedimentary evidence ». Hydrology and Earth System Sciences 26, no 5 (10 mars 2022) : 1341–56. http://dx.doi.org/10.5194/hess-26-1341-2022.
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Abstract. Since the Quaternary Period, paleo-seawater intrusions have been suggested to explain the observed saline groundwater that extends far inland in coastal zones. The Luanhe River delta (northwest coast of the Bohai Sea, China) is characterized by the distribution of saline, brine, brackish, and fresh groundwater from the coastline inland. The groundwater in this region exhibits a wide range of total dissolved solids (TDS): 0.38–125.9 g L−1. Meanwhile, previous studies have revealed that this area was significantly affected by Holocene marine transgression. This study used hydrochemical, isotopic, and sedimentological methods to investigate groundwater salinization processes in the Luanhe River delta and its links to paleo-environmental settings. Isotopic results (2H, 18O, 14C) allowed old groundwater recharge to be distinguished from new groundwater recharge. Hydrochemical analysis using the PHREEQC code indicated that the salt in saline and brine groundwater originates from a marine source. The 18O–Cl relationship diagram yields three-end-member groundwater mixing, and two mixing scenarios are suggested to explain the freshening and salinization processes in the study area. When this was interpreted along with data from paleo-environmental sediments, we found that groundwater salinization may have occurred since the Holocene marine transgression. The brine is characterized by radiocarbon activities of ∼ 50–85 pMC and relatively depleted stable isotopes, which are associated with seawater evaporation in the ancient lagoon during delta progradation and mixing with deeper fresh groundwater, which was probably recharged in the cold Late Pleistocene. The brackish and fresh groundwaters are characterized by river-like stable isotope values, where high radiocarbon activities (74.3–105.9 pMC) were formed after the washing out of the salinized aquifer by surface water in the delta plain. This study presents an approach that utilizes geochemical indicator analysis with paleo-geographic reconstruction to better assess groundwater evolutionary patterns in coastal aquifers.
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Listyani R.A., T., et Sri Ning Peni. « Chemical Type Variation of Groundwater in Borobudur and Surroundings Area, Magelang District ». E3S Web of Conferences 202 (2020) : 12005. http://dx.doi.org/10.1051/e3sconf/202020212005.
Texte intégralRésumé :
Hydrogeological surveys have been carried out in the Borobudur area and its surroundings, the northern part of the West Progo Hills to the Magelang intermountain plains. The purpose of this study is to determine the variations in groundwater’s chemical types in the study area and to interpret the hydrochemical processes. Primary data was taken in the field, including groundwater data and rock petrology. Physical / chemical data of groundwater were obtained from laboratory test results. Data analysis includes hydrochemical analysis using the Stiff, Piper, and Durov diagrams. The result shows that groundwater in the study area has a wide variety of chemical types, namely Ca, Mg - bicarbonate; Ca, Mg, alkaline – bicarbonate; Alkaline, Ca – chloride, and Alkaline - chloride. Groundwater in the study area is fresh (type Va) to brackish (type Vc), with low -moderate TDS content (119 - 6,810 ppm), and soft calcium carbonate hardness (6.0 - 16.6 ppm). Hydrochemical processes occur in groundwater are simple dissolution and cation exchange caused by clay materials originating from Quaternary deposits or weathering of Old Andesite Formation volcanic breccia. In addition, the presence of brackish water in Karangrejo and Candirejo may be triggered by mixing with fossil water.
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Dhok, R. P., A. S. Patil et V. S. Ghole. « Sodicity and Salinity Hazards in Water Flow Processes in the Soil ». E-Journal of Chemistry 8, s1 (2011) : S474—S480. http://dx.doi.org/10.1155/2011/854756.
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Groundwater is one of the natural resource with the potential for domestic, agricultural and industrial consumption. This paper presents the results of the distribution of salinity characteristics (electrical conductivity and sodium adsorption ratio) of groundwater and based on the results, the evaluation of the sodicity and salinity hazards or in the processes if such groundwater is used for such purposes has been restrictive. This is because of the salinization of aquifers generated by rock salt present below the aquifers. The issue was studied for the groundwater environment in the Karha river basin area, Baramati, Pune, (M.S.) India, for the period of September 2009 to August 2010. The measured data were presented in the form of graphical attachments. The average annual values of the electrical conductivity of groundwater ranged from 490 to 8920 µS/cm in the examined period. Data obtained from analysis signifies the salinity of groundwater in study area is high to very high salinity and can’t be used for crops in a soil with restricted drainage but it can be used under very special circumstances. The sodium adsorption ratio values indicate low, medium to high sodium salinization of the groundwater.
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Nowreen, Sara, R. G. Taylor, M. Shamsudduha, M. Salehin, A. Zahid et K. M. Ahmed. « Groundwater recharge processes in an Asian mega-delta : hydrometric evidence from Bangladesh ». Hydrogeology Journal 28, no 8 (7 octobre 2020) : 2917–32. http://dx.doi.org/10.1007/s10040-020-02238-3.
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AbstractGroundwater is used intensively in Asian mega-deltas yet the processes by which groundwater is replenished in these deltaic systems remain inadequately understood. Drawing insight from hourly monitoring of groundwater levels and rainfall in two contrasting settings, comprising permeable surficial deposits of Holocene age and Plio-Pleistocene terrace deposits, together with longer-term, lower-frequency records of groundwater levels, river stage, and rainfall from the Bengal Basin, conceptual models of recharge processes in these two depositional environments are developed. The representivity of these conceptual models across the Bengal Basin in Bangladesh is explored by way of statistical cluster analysis of groundwater-level time series data. Observational records reveal that both diffuse and focused recharge processes occur in Holocene deposits, whereas recharge in Plio-Pleistocene deposits is dominated by indirect leakage from river channels where incision has enabled a direct hydraulic connection between river channels and the Plio-Pleistocene aquifer underlying surficial clays. Seasonal cycles of recharge and discharge including the onset of dry-season groundwater-fed irrigation are well characterised by compiled observational records. Groundwater depletion, evident from declining groundwater levels with a diminished seasonality, is pronounced in Plio-Pleistocene environments where direct recharge is inhibited by the surficial clays. In contrast, intensive shallow groundwater abstraction in Holocene environments can enhance direct and indirect recharge via a more permeable surface geology. The vital contributions of indirect recharge of shallow groundwater identified in both depositional settings in the Bengal Basin highlight the critical limitation of using models that exclude this process in the estimation of groundwater recharge in Asian mega-deltas.
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Ogwah, C., et MO Eyankware. « Hydrogeochemical processes in groundwater resources located around abandoned Okpara coal, Enugu SE. Nigeria ». Bangladesh Journal of Scientific and Industrial Research 55, no 4 (27 décembre 2020) : 245–52. http://dx.doi.org/10.3329/bjsir.v55i4.50960.
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A detail understanding of the hydrogeochemical characteristics and groundwater quality is indispensable for the sustainable utilization of the groundwater sources. This is in line with sustainable development goal of United Nation. The following parameters were analyzed using APHA, 2012 standard: pH, Ec, total dissolved solid (TDS,) total hardness (TH), magnesium (Mg2+), sulphate (SO4 2¯), chloride (Cl¯), bicarbonate (HCO3¯), carbonate (CO3 2¯), nitrate (NO3¯), potassium (K+), sodium (Na2+)and calcium (Ca2+). Findings revealed that pH value reveals that groundwater is acidic. Bivariate plots showed that groundwater quality is influenced by number of factors. Hydrogeochemical assessment of groundwater samples was based on the following model:End-member, Parson’s and Diamond field plots. Results from these plots revealed that silicate and carbonate weathering are the major factors that control groundwater quality and that groundwater samples were of different water type namely, Ca–Mg–SO4, Ca–Mg–Cl, Na–SO4 water type and high Ca+Mg & SO4+Cl respectively. It was observed that 99 % of groundwater within the study area fell within fresh water category and groundwater is influenced by various factors.
Bangladesh J. Sci. Ind. Res.55(4), 245-252, 2020
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Sizykh, M. R., A. A. Batoeva et D. G. Aseev. « CAVITATIONALACTIVATION OF DEFERRIZATION PROCESSES OF NATURAL GROUNDWATER ». International Journal of Applied and Fundamental Research (Международный журнал прикладных и фундаментальных исследований) 1, no 12 2018 (2018) : 9–14. http://dx.doi.org/10.17513/mjpfi.12512.
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Garven, Grant. « Continental-Scale Groundwater Flow and Geologic Processes ». Annual Review of Earth and Planetary Sciences 23, no 1 (mai 1995) : 89–117. http://dx.doi.org/10.1146/annurev.ea.23.050195.000513.
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Ratri, D., D. P. E. Putra et W. Wilopo. « Groundwater geochemistry and hydrogeochemical processes assessment in Bantul, Yogyakarta, Indonesia ». IOP Conference Series : Earth and Environmental Science 958, no 1 (1 décembre 2021) : 012013. http://dx.doi.org/10.1088/1755-1315/958/1/012013.
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Abstract In Bantul, Southern Yogyakarta, groundwater is the main source of domestic water needs. Therefore, knowing the hydrogeochemistry of groundwater is crucial in order to manage a sustainable groundwater resource. To characterize the compelling geochemical processes that control the groundwater chemistry, further hydrogeochemical examinations were directed in the area. Thirty groundwater samples were collected from shallow dug wells during the early dry season (April 2021). Sampling procedures and chemical analysis were carried out as per standard methods with secondary data obtained in 2006. The geochemical evaluations were depicted using several graphical plots dependent on the ionic constituents, hydrochemical facies, and controlling factors of groundwater quality. Two major hydrochemical facies were identified: alkaline-earth water with higher alkali; bicarbonate predominated (62%) and alkaline-earth water; bicarbonate predominated (32%). Weathering of silicate minerals occurs in 70% of recent samples and predominantly regulates major ion chemistry such as calcium, magnesium, sodium, and potassium. Chloro-alkaline indices 1,2 values signify that there are two potential rock-water interaction processes in the study region, namely the ion exchange and reverse ion exchange. Concentrations of nitrate, sulfate, and chloride indicate that the water chemistry has not been heavily contaminated by the land use in the area and is still mainly controlled by geogenic processes rather than anthropogenic activities.
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Schwab, Valérie F., Martina Herrmann, Vanessa-Nina Roth, Gerd Gleixner, Robert Lehmann, Georg Pohnert, Susan Trumbore, Kirsten Küsel et Kai U. Totsche. « Functional diversity of microbial communities in pristine aquifers inferred by PLFA- and sequencing-based approaches ». Biogeosciences 14, no 10 (31 mai 2017) : 2697–714. http://dx.doi.org/10.5194/bg-14-2697-2017.
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Abstract. Microorganisms in groundwater play an important role in aquifer biogeochemical cycles and water quality. However, the mechanisms linking the functional diversity of microbial populations and the groundwater physico-chemistry are still not well understood due to the complexity of interactions between surface and subsurface. Within the framework of Hainich (north-western Thuringia, central Germany) Critical Zone Exploratory of the Collaborative Research Centre AquaDiva, we used the relative abundances of phospholipid-derived fatty acids (PLFAs) to link specific biochemical markers within the microbial communities to the spatio-temporal changes of the groundwater physico-chemistry. The functional diversities of the microbial communities were mainly correlated with groundwater chemistry, including dissolved O2, Fet and NH4+ concentrations. Abundances of PLFAs derived from eukaryotes and potential nitrite-oxidizing bacteria (11Me16:0 as biomarker for Nitrospira moscoviensis) were high at sites with elevated O2 concentration where groundwater recharge supplies bioavailable substrates. In anoxic groundwaters more rich in Fet, PLFAs abundant in sulfate-reducing bacteria (SRB), iron-reducing bacteria and fungi increased with Fet and HCO3− concentrations, suggesting the occurrence of active iron reduction and the possible role of fungi in meditating iron solubilization and transport in those aquifer domains. In more NH4+-rich anoxic groundwaters, anammox bacteria and SRB-derived PLFAs increased with NH4+ concentration, further evidencing the dependence of the anammox process on ammonium concentration and potential links between SRB and anammox bacteria. Additional support of the PLFA-based bacterial communities was found in DNA- and RNA-based Illumina MiSeq amplicon sequencing of bacterial 16S rRNA genes, which showed high predominance of nitrite-oxidizing bacteria Nitrospira, e.g. Nitrospira moscoviensis, in oxic aquifer zones and of anammox bacteria in more NH4+-rich anoxic groundwater. Higher relative abundances of sequence reads in the RNA-based datasets affiliated with iron-reducing bacteria in more Fet-rich groundwater supported the occurrence of active dissimilatory iron reduction. The functional diversity of the microbial communities in the biogeochemically distinct groundwater assemblages can be largely attributed to the redox conditions linked to changes in bioavailable substrates and input of substrates with the seepage. Our results demonstrate the power of complementary information derived from PLFA-based and sequencing-based approaches.
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Pazand, Kamran, et Kaveh Pazand. « Chemical characteristics of groundwater in Ardabil region, Iran ». Ecofeminism and Climate Change 1, no 3 (16 juillet 2020) : 141–49. http://dx.doi.org/10.1108/efcc-05-2020-0013.
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Purpose The chemical analysis of wells in the Ardabil area, Ardabil Province NW of Iran, was evaluated to determine the hydrogeochemical processes and ion concentration background in the region. The purpose of this study is to analyze the hydrochemical quality of groundwater in Ardabil aquifer in order to assess the suitability of the waters for different uses. Design/methodology/approach The chemical analysis of 75 water wells in the Ardabil area, was evaluated. Over the entire area, the dominated hydrochemical types are: Na-Cl, Na-HCO3-Cl-Mg, Ca-SO4, Ca-Mg-SO4-Cl and Ca-Mg-HCO3. The abundance of the major ions is as follows: Na+>Ca2+>Mg2+>K+ and SO42–> Cl–>HCO3– and major ion concentrations are below the acceptable level for drinking water. Most of groundwater samples fell in the soft water category. All of groundwaters belong to the excellent category and can be used safely for irrigation. Findings The chemical analysis of 75 water wells in the Ardabil area, Ardabil Province NW of Iran, was evaluated to determine the hydrogeochemical processes and ion concentration background in the region. Over the entire area, the dominated hydrochemical types are: Na-Cl, Na-HCO3-Cl-Mg, Ca-SO4, Ca-Mg-SO4-Cl and Ca-Mg-HCO3. The abundance of the major ions is as follows: Na+>Ca2+>Mg2+>K+ and SO42–> Cl–>HCO3– and major ion concentrations are below the acceptable level for drinking water. Most of groundwater samples fell in the soft water category. All of groundwaters belong to the excellent category and can be used safely for irrigation. Originality/value The chemical analysis of 75 water wells in the Ardabil area, Ardabil Province NW of Iran, was evaluated to determine the hydrogeochemical processes and ion concentration background in the region. Over the entire area, the dominated hydrochemical types are: Na-Cl, Na-HCO3-Cl-Mg, Ca-SO4, Ca-Mg-SO4-Cl and Ca-Mg-HCO3. The abundance of the major ions is as follows: Na+>Ca2+>Mg2+>K+ and SO42–> Cl–>HCO3– and major ion concentrations are below the acceptable level for drinking water. Most of groundwater samples fell in the soft water category. All of groundwaters belong to the excellent category and can be used safely for irrigation.
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Horn, Diane P. « Beach groundwater dynamics ». Geomorphology 48, no 1-3 (novembre 2002) : 121–46. http://dx.doi.org/10.1016/s0169-555x(02)00178-2.
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Sterckx, Arnaud, Jean-Michel Lemieux et Rein Vaikmäe. « Representing Glaciations and Subglacial Processes in Hydrogeological Models : A Numerical Investigation ». Geofluids 2017 (2017) : 1–12. http://dx.doi.org/10.1155/2017/4598902.
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The specific impact of glacial processes on groundwater flow and solute transport under ice-sheets was determined by means of numerical simulations. Groundwater flow and the transport of δ18O, TDS, and groundwater age were simulated in a generic sedimentary basin during a single glacial event followed by a postglacial period. Results show that simulating subglacial recharge with a fixed flux boundary condition is relevant only for small fluxes, which could be the case under partially wet-based ice-sheets. Glacial loading decreases overpressures, which appear only in thick and low hydraulic diffusivity layers. If subglacial recharge is low, glacial loading can lead to underpressures after the retreat of the ice-sheet. Isostasy reduces considerably the infiltration of meltwater and the groundwater flow rates. Below permafrost, groundwater flow is reduced under the ice-sheet but is enhanced beyond the ice-sheet front. Accounting for salinity-dependent density reduces the infiltration of meltwater at depth. This study shows that each glacial process is potentially relevant in models of subglacial groundwater flow and solute transport. It provides a good basis for building and interpreting such models in the future.
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Sarker, Md Mizanur Rahman, Thomas Hermans, Marc Van Camp, Delwar Hossain, Mazeda Islam, Nasir Ahmed, Md Abdul Quaiyum Bhuiyan, Md Masud Karim et Kristine Walraevens. « Identifying the Major Hydrogeochemical Factors Governing Groundwater Chemistry in the Coastal Aquifers of Southwest Bangladesh Using Statistical Analysis ». Hydrology 9, no 2 (1 février 2022) : 20. http://dx.doi.org/10.3390/hydrology9020020.
Texte intégralRésumé :
People in the southwestern (SW) coastal part of Bangladesh are suffering from a severe freshwater crisis due to saline groundwater at a shallow depth. Fresh groundwater below a 200 m depth is an option, but it is costly to construct deep tubewells for the local inhabitants. The processes of salinization and freshening were previously identified using conventional methods. In this study, we brought new insight into these processes by analyzing existing datasets using multivariate statistics to identify the factors affecting groundwater chemistry. Cluster analysis (CA) revealed three major clusters. Cluster A corresponded to saline (NaCl-type) water. Cluster B was also saline (NaCl-type) water but showed mixing effects. Cluster C was fresh groundwater (NaHCO3-type) and isolated. The hydrochemical characteristics of clusters A, B and C compared remarkably well with the groundwaters from the upper shallow aquifer (USA), lower shallow aquifer (LSA) and deep aquifer (DA), respectively. Factor analysis (FA) showed that 75% of the total variance was influenced by evaporate dissolution, carbonate dissolution/precipitation, cation exchange and anthropogenic pollution to some extent. Therefore, the integrated approach showed the validity of applying multivariate statistical techniques to infer the dominant hydrochemistry and to characterize and understand a complicated hydrogeological system.
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Živančev, Nevena, Srđan Kovačević, Marija Perović, Aleksandar Čalenić et Milan Dimkić. « Influence of oxic and anoxic groundwater conditions on occurrence of selected agrochemicals ». Water Supply 20, no 2 (5 décembre 2019) : 487–98. http://dx.doi.org/10.2166/ws.2019.178.
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Abstract The occurrence and mitigation of selected pesticides and nitrates in surface and groundwater samples from two alluvions in the Republic of Serbia are investigated in this study. The influence of aquifer conditions on the degradation processes of pesticides and nitrates is considered as a potential removal mechanism of compound residues in alluvial groundwater. Nitrate concentration was analyzed in 144 groundwater samples in the Kovin-Dubovac drainage system and 63 samples at the Ključ groundwater source. The occurrence of 15 pesticides was monitored in groundwater in a total of 34 samples in the Kovin-Dubovac area and 14 samples at the Ključ groundwater source. Concentrations of selected pesticides and nitrates were monitored in eight samples from the Danube in the Kovin-Dubovac area and 15 samples from Velika Morava at the Ključ groundwater source. Both selected locations are agricultural areas. Results show that concentrations of nitrates (NO3−) are much higher in oxic groundwater conditions compared with concentrations in typical anoxic conditions. The opposite is the case for the concentration of pesticides that occurred in surface and groundwater samples. These results are very important for a better understanding of the self-purification potential of alluvial aquifers and assessment of aquifer condition influence, especially oxic or anoxic conditions, on the occurrence and mitigation of selected agrochemical residues in groundwaters.
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Olichwer, Tomasz, Robert Tarka et Magdalena Modelska. « Chemical composition of groundwaters in the Hornsund region, southern Spitsbergen ». Hydrology Research 44, no 1 (11 juillet 2012) : 117–30. http://dx.doi.org/10.2166/nh.2012.075.
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Chemical composition of groundwaters was investigated in the region of the Hornsund fjord (southern Spitsbergen). The investigations were conducted during polar expeditions organized by the University of Wroclaw in two summer seasons of 2003 and 2006. Three zones of groundwater circulation: suprapermafrost, intrapermafrost and subpermafrost, were identified in areas of perennial permafrost in the region of Hornsund. The zone of shallow circulation occurs in non-glaciated (suprapermafrost) and subglacial areas. In this zone, the chemical composition of groundwater originates from initial chemical composition of precipitation, mineralogical composition of bedrock, oxidation of sulphides and dissolution of carbonates. The intermediate system of circulation is connected with water flow inside and below perennial permafrost (intrapermafrost and subpermafrost). In this zone, the chemical composition of groundwater is mainly controlled by dissolution of carbonates, ion exchange processes involving Ca2+ substitution by Na+, and oxidation of sulphides under oxygen-depleted conditions. The subpermafrost zone (deep groundwater circulation) occurs in deep-tectonic fractures, which are likely conduits for the descent of shallow groundwater to deeper depths. In this zone, the groundwater shows lower mineralization comparing to intrapermafrost zone and has a multi-ion nature Cl–HCO3–Na-Ca–Mg.
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Rissmann, C. W. F., M. I. Leybourne, C. Benn, J. A. Kidder et L. K. Pearson. « Comparison of groundwater composition from the Monturaqui and Punta Negra Basins, northern Chile : implications for porphyry copper exploration ». Geochemistry : Exploration, Environment, Analysis 22, no 2 (14 février 2022) : geochem2021–056. http://dx.doi.org/10.1144/geochem2021-056.
Texte intégralRésumé :
Groundwaters recovered from the Salar de Punta Negra and Monturaqui basins in the Atacama Desert of northern Chile exhibit distinctly different isotopic, major, trace, and porphyry copper elemental compositions related to contrasting morphostructural, geochemical, and hydrodynamic settings. Comparison of these distinct groundwater signatures with groundwaters from known porphyry copper deposits (Salar de Hamburgo and Spence Deposit), can be used to determine if either basin might be prospective for porphyry copper mineralization. Groundwaters within the Punta Negra Basin exhibit geochemical characteristics consistent with other closed basin settings throughout the arid Andes. Elemental and isotopic compositions within the Punta Negra Basin reflect closed basin evaporitic processes consistent with the hyperarid, volcanic setting of the central Andes. Pathfinder metals and isotopic compositions are not consistent with porphyry copper type mineralization as described for groundwaters within the Salar de Hamburgo Basin, and the Spence Deposit. Within the Monturaqui Basin the geochemical composition of groundwaters are characteristic of diffuse hydrothermal activity. Sulfur isotopic composition within the waters of the northern Monturaqui Basin exhibit δ34SCDT isotopic signatures that fall within the range for sulfide mineralization as reported for groundwaters in and around the Spence Deposit and the Salar de Hamburgo. However, porphyry copper related elements within the Monturaqui Basin are impoverished relative to groundwaters of the Spence and Escondida Deposit. Such impoverishment in porphyry related elements, taken in conjunction with enriched δ13CPDB compositions, elevated groundwater temperatures, groundwater compositions dominated by HCO3, SO4, and Si, and the proximity of the Monturaqui Basin to the current magmatic arc are consistent with a volcanic hydrothermal origin. In summary, the groundwater geochemistry of the Monturaqui and Punta Negra Basins are not indicative of porphyry copper-type mineralization.Thematic collection: This article is part of the Hydrochemistry related to exploration and environmental issues collection available at: https://www.lyellcollection.org/cc/hydrochemistry-related-to-exploration-and-environmental-issues
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Xu, Naizheng, Jianshi Gong, Xiaohu Tao et Lin Liu. « Hydrogeochemical Processes and Potential Exposure Risk of Arsenic-Rich Groundwater from Huaihe River Plain, China ». Water 14, no 5 (22 février 2022) : 693. http://dx.doi.org/10.3390/w14050693.
Texte intégralRésumé :
Arsenic poses a danger to environmental health, and arsenic-rich groundwater is a key exposure risk for humans. The distribution, migration, and enrichment of arsenic in groundwater is an important environmental and public health problem. Currently, the Huaihe River Basin is identified as a region of arsenic-rich groundwater in China. This study aims to assess arsenic-rich groundwater potential pollution risk, analyze the hydrogeochemical processes, and trace the ion source based on an analysis of groundwater hydrogeochemical data. The results show that arsenic is the main inorganic chemical substances affecting the water quality in the study area, which presents a high exposure risk for public health. The arsenic concentration of groundwater was f 5.75 ± 5.42 μg/L, and 23% of the considered samples exceeded the drinking water standards of the World Health Organization. The groundwater in the study area underwent evaporation, halite dissolution, and ion exchange processes. The total alkalinity (HCO3−) of the arsenic-rich groundwater mainly ranged between 400–700 mg/L, and the chemical type was mainly of HCO3-Na. In an alkaline environment, the oxidative dissolution and reductive dissolution of arsenic bearing minerals might be the formation mechanism of arsenic-rich groundwater.
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Eissa, Mustafa, Hosam Shawky, Amira Samy, Mostafa Khalil et Mohamed El Malky. « Geochemical and Isotopic Evidence of Groundwater Salinization Processes in El Dabaa Area, Northwestern Coast, Egypt ». Geosciences 8, no 11 (29 octobre 2018) : 392. http://dx.doi.org/10.3390/geosciences8110392.
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El Dabaa city is located along the northwestern coast ridge zone of Egypt, where the groundwater is the major water source for drinking, domestic, and agricultural purposes. The groundwater salinity increased over the last decades, therefore, geochemical techniques and environmental isotopes have been utilized to identify the main groundwater recharge and salinization sources. The study area comprises two main groundwater aquifers: the porous oolitic Pleistocene and the fractured limestone Miocene aquifers. The groundwater salinity of the Pleistocene aquifer ranges from 751 to 27,870 mg/L, with an average value of 6006 mg/L. The salinity of the Miocene aquifer ranges from 3645 to 41,357 mg/L, with an average value of 11,897 mg/L. Fresh and brackish groundwater have been recorded in the shallow hand-dug wells, while saline groundwater has been found in deeper wells close to the shoreline. Groundwater samples have been categorized into two distinct groups according to the salinity ranges, hydrochemical ion ratios, and stable isotopic content. Group I is composed of groundwater with salinity less than 10,000 mg/L, and depleted stable isotopic content (−5.64 < δ18O < −2.45; −23.5 < δ2H < −0.02), while Group II contains groundwater with salinity values above 10,000 mg/L and relatively enriched stable isotopic content (−1.86 < δ18O < −0.48; −10.3 < δ2H < −2.0). The weight mass balance mixing model shows that Group I falls close to the rain and/or water extract samples, indicating meteoric water origin that has evolved due to leaching and dissolution processes. Group II is mostly located between the rainwater and the seawater samples, revealing mixing with water of marine origin due to groundwater overexploitation. The estimated seawater mixing index (SMI) of groundwater samples of Group II is greater than one, which confirms mixing with seawater. The water-rock reaction NETPATH (geochemical groundwater reaction and mixing code) model scenarios representing Group I suggests that gypsum, dolomite, and halite are dissolved, while calcite is formed with a slight influence from evaporation processes. Six mixing models representing Group II are used to investigate seawater mixing scenarios. The models suggest that illite and dolomite are dissolved, while calcite and gypsum are precipitated with a seawater mixing ratios ranging from 28% to 98%. In conclusion, due to the scarcity of annual groundwater recharge in the El Dabaa area, groundwater withdrawal should be well managed to avoid groundwater salinization and further seawater intrusion.
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Ronchetti, F., L. Borgatti, F. Cervi, C. Gorgoni, L. Piccinini, V. Vincenzi et A. Corsini. « Groundwater processes in a complex landslide, northern Apennines, Italy ». Natural Hazards and Earth System Sciences 9, no 3 (18 juin 2009) : 895–904. http://dx.doi.org/10.5194/nhess-9-895-2009.
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Abstract. The hydrogeological characteristics of roto-translational slides in flysch are complex, due to the inherent anisotropy and heterogeneity of rock masses and related deposits. The paper deals with the hydrogeological characterization of a reactivated roto-translational slide affecting Cretaceous flysch rocks, located in the northern Apennines of Italy. Continuous monitoring of groundwater levels, in-situ permeability and pumping tests, hydrochemical and physical analyses and Uranine tracers were the adopted prospecting methods. In this research hydrological monitoring and investigation are summarized in order to define a hydrogeological conceptual model of the landslide source area. Results showed that two overlaying hydrogeological units exist at the slope scale: the first is unconfined, but highly compartmentalized, and hosted in the fractured and dismembered rock slide body. The second is confined and lays in the undisturbed flysch below the sliding surface. The groundwater level in the confined hydrogeological unit is twenty meters higher than the groundwater level in the uppermost one. Moreover, the groundwater chemistry characterization revealed a rising of deep fluids in the landslide area.
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Ogwah, C., et M. O. Eyankware. « INVESTIGATION OF HYDROGEOCHEMICAL PROCESSES IN GROUNDWATER RESOURCES LOCATED AROUND ABANDONED OKPARA COAL MINE, ENUGU SE. NIGERIA ». Journal CleanWAS 4, no 1 (23 mars 2020) : 12–16. http://dx.doi.org/10.26480/jcleanwas.01.2020.12.16.
Texte intégralRésumé :
A detail understanding of the hydrogeochemical characteristics and groundwater quality is indispensable for the sustainable utilization of the groundwater sources. This is in line with Sustainable development goal of United Nation. The following parameters were analyzed using APHA, 2012 standard: pH, Ec, total dissolved solid (TDS,) total hardness (TH), magnesium (Mg2+), sulphate (SO42¯), chloride (Cl¯), bicarbonate (HCO3¯), carbonate (CO32¯), nitrate ( NO3¯), potassium (K+), sodium (Na2+) and calcium (Ca2+). Findings revealed that pH value reveals that groundwater is acidic. Bivariate plots showed that groundwater quality is influenced by number of factors. Hydrogeochemical assessment of groundwater samples was based on the following model: End-member, Parson’s and Diamond field plots. Results from these plots revealed that that silicate and carbonate weathering are that major factor that control groundwater quality, and that groundwater samples were of different water type namely; Ca–Mg–SO4, Ca–Mg–Cl, Na–SO4 water type and high Ca + Mg & SO4 + Cl respectively. It was observed that 99 % of groundwater within the study area fell within fresh water category and groundwater is influenced by various factors such as weathering.
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Kravchenko, Oleksandr. « ROLE OF BIOLOGICAL PROCESSES DURING MANGANESE REMOVAL FROM UNDERGROUND WATER ». EUREKA : Physics and Engineering 1 (29 janvier 2016) : 61–67. http://dx.doi.org/10.21303/2461-4262.2016.00027.
Texte intégralRésumé :
This article briefly presents the results of the effect of oxidants during filtration of groundwater with high level of manganese compounds. Significant role of biological processes along with physico-chemical at demanganation of groundwater has been noticed. It has been studied that biological processes are dominated in low concentrations of oxidants. At high concentration of disinfectant the role of physico-chemical processes begin to dominate. Thus, there is a significant role of microorganisms in physico-chemical process of manganese removal. Obtained results showed that the oxygen is more efficient oxidizer than sodium hypochlorite for compounds of manganese presented in groundwater.
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Neal, C., A. J. Robson, P. Shand, W. M. Edmunds, A. J. Dixon, D. K. Buckley, S. Hill et al. « The occurrence of groundwater in the Lower Palaeozoic rocks of upland Central Wales ». Hydrology and Earth System Sciences 1, no 1 (31 mars 1997) : 3–18. http://dx.doi.org/10.5194/hess-1-3-1997.
Texte intégralRésumé :
Abstract. A series of boreholes of up to 50 m depth, drilled into Lower Palaeozoic mudstone, shale and greywacke bedrock in the headwater catchment areas of the River Severn at Plynlimon in Central Wales, shows an extensive chemically- and hydrologically-active shallow groundwater fracture flow system. Groundwater chemistry varies in space and time with lowest water levels and highest alkalinities occurring during the drier summer months. The groundwaters are enriched in base cations, silica, sulphate and alkalinity relative to surface waters indicating significant silicate weathering sources and sulphide oxidation. These sources provide important contributions to both stream water quality and flow. At one site, the introduction of a borehole near to the main river opened bedrock fractures which increased the amount of groundwater entering the river. This had a profound effect on the river water quality by increasing the pH, alkalinity and calcium concentrations. As well as pointing to the possibility of the wider availability of groundwater resources in upland areas, the results highlight (a) the potential value of groundwater as a acid neutralizing resource, (b) the importance of weathering processes and flow routing within the groundwater environment for stream water chemistry, (c) the potential for altering stream water quality by manipulation of groundwater routing and (d) the need to include groundwater characteristics in hydrochemical management models of surface water acidification.
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Antonio Giusti, Donizeti. « Forecast and Prevention Processes for Groundwater Exploitation in Curitiba, Brazil ». Water Science and Technology 24, no 11 (1 décembre 1991) : 201–3. http://dx.doi.org/10.2166/wst.1991.0352.
Texte intégralRésumé :
Geological studies were made as a contribution to planning the future urban and industrial occupation of Curitiba area - PR. Geophysical and hydrogeological studies showed: the structural geology and geological contacts; the watertable and groundwater flow direction; topographical configuration of the underling crystalline basement. The listing of different land uses and their locations represents an aid to the diagnosis, forecast and prevention process of groundwater degradation. By means of the superposition of land use and territory occupation maps and geological and hydrogeological maps, recommendations are made to alter the present urban and industrial occupation forms. This research represents a tentative contribution to the groundwater exploitation and urban development of the Curitiba area.