The Gabes aquifer system,located in southeastern Tunisia,is a crucial resource for supporting local socio-economic activities.Due to its dual porosity structure,is particularly vulnerable to pollution.This study aims ...The Gabes aquifer system,located in southeastern Tunisia,is a crucial resource for supporting local socio-economic activities.Due to its dual porosity structure,is particularly vulnerable to pollution.This study aims to develop a hybrid model that combines the Fracture Aquifer Index(FAI)with the conventional GOD(Groundwater occurrence,Overall lithology,Depth to water table)method,to assess groundwater vulnerability in fractured aquifer.To develop the hybrid model,the classical GOD method was integrated with FAI to produce a single composite index.Each parameter within both GOD and FAI was scored,and a final index was calculated to delineate vulnerable areas.The results show that the study area can be classified into four vulnerability levels:Very low,low,moderate,and high,indicating that approximately 8%of the area exhibits very low vulnerability,29%has low vulnerability,25%falls into the moderate category,and 38%is considered highly vulnerable.The FAI-GOD model further incorporates fracture network characteristics.This refinement reduces the classification to three vulnerability classes:Low,medium,and high.The outcomes demonstrate that 46%of the area is highly vulnerable due to a dense concentration of fractures,while 17%represents an intermediate zone characterized by either shallow or deeper fractures.In contrast,37%corresponds to areas with lightly fractured rock,where the impact on vulnerability is minimal.Multivariate statistical analysis was employed using Principal Components Analysis(PCA)and Hierarchical Cluster Analysis(HCA)on 24 samples across six variables.The first three components account for over 76%of the total variance,reinforcing the significance of fracture dynamics in classifying vulnerability levels.The FAI-GOD model removes the very-low-vulnerability class and expands the spatial extent of low-and high-vulnerability zones,reflecting the dominant influence of fracture networks on aquifer sensitivity.While both indices use a five-class system,FAI-GOD redistributes vulnerability by eliminating very-low-vulnerability areas and amplifying low/high categories,highlighting the critical role of fractures.A strong correlation(R2=0.94)between the GOD and FAI-GOD indices,demonstrated through second-order polynomial regression,confirms the robustness of the FAI-GOD model in accurately predicting vulnerability to pollution.This model provides a useful framework for assessing the vulnerability of complex aquifers and serves as a decision-making tool for groundwater managers in similar areas.展开更多
One of the pathways to attain NET ZERO is CO_(2)injection into deep saline aquifers(DSAs),which alters the saturation and pore pressure of the reservoir rocks,hence the effective stress,sʹ.This,in turn,would change th...One of the pathways to attain NET ZERO is CO_(2)injection into deep saline aquifers(DSAs),which alters the saturation and pore pressure of the reservoir rocks,hence the effective stress,sʹ.This,in turn,would change their geomechanical(i.e.peak deviatoric stress,elastic modulus,Poisson's ratio)and petrophysical(porosity and permeability)properties.Such a situation might trigger geo-hazards,like induced seismicity,ground deformation,caprock failure.Hence,reducing the risk of such hazards necessitates quantifying the spatial and temporal changes in sʹ,under specific CO_(2)and/or brine saturation,designated as S_(CO2)and S_(b),respectively,and resultant pore pressure.With this in view,a conceptual model depicting the reservoir,demarcated by five zones based on variations in saturation,pore-pressure,temperature,etc.,and the corresponding effective stress equations have been proposed based on the available literature.Furthermore,a critical review of literature has been carried out to decipher the limitations and contradictions associated with the findings from(i)laboratory studies to estimate S_(CO2)employing pwave velocity and electrical resistivity,(ii)analytical and numerical approaches for estimating the variation of pore-pressure in the reservoir rocks,and(iii)laboratory studies on variation in geomechanical and petrophysical properties under the conditions representative of the above-mentioned zones of the conceptual model.The authors consider that extensive experiments should be conducted on the rocks from different sources and tested under various conditions of the CO_(2)injection to validate the proposed model for the execution of risk-free CO_(2)storage in DSAs.展开更多
Groundwater quality is pivotal for sustainable resource management,necessitating comprehen-sive investigation to safeguard this critical resource.This study introduces a novel methodology that inte-grates stiff diagra...Groundwater quality is pivotal for sustainable resource management,necessitating comprehen-sive investigation to safeguard this critical resource.This study introduces a novel methodology that inte-grates stiff diagrams,geostatistical analysis,and geometric computation to delineate the extent of a confined aquifer within the Chahrdoly aquifer,located west of Hamadan,Iran.For the first time,this approach combines these tools to map the boundaries of a confined aquifer based on hydrochemical characteristics.Stiff diagrams were used to calculate geometric parameters from groundwater chemistry data,followed by simulation using a linear model incorporating the semivariogram parameterγ(h).The Root Mean Square Error(RMSE)of the linear model was used to differentiate confined from unconfined aquifers based on hydrochemical signatures.Validation was conducted by generating a cross-sectional hydrogeological layer from well logs,confirming the presence of aquitard layers.The results successufully delineated the confined aquifer's extent,showing strong agreement with hydrogeological log data.By integrating stiff diagrams with semivariogram analysis,this study enhances the understanding of hydrochemical processes,offering a robust framework for groundwater resource identification and management.展开更多
In the Maradi region,the alluvial aquifer of the Goulbi’N Maradi rests on the aquifers of the Continental Hamadien.It represents an essential reserve for irrigation and drinking water supply.However,due to its high d...In the Maradi region,the alluvial aquifer of the Goulbi’N Maradi rests on the aquifers of the Continental Hamadien.It represents an essential reserve for irrigation and drinking water supply.However,due to its high demand and the excessive use of chemical fertilizers and pesticides in irrigation,a ten-year analysis of the dynamics of this alluvial aquifer has proven necessary.Hence,this study,based on hydrodynamic and hydrochemical approaches,aims to improve knowledge of the dynamics of the alluvial aquifer from 2015 to 2023.The novelty of this study lies in its comprehensive coverage of the entire Goulbi N’Maradi valley in Niger,employing a multidimensional approach.The data used were composed of water samples taken from forty-five structures,piezometric monitoring sheets,and digital terrain models.The results reveal that the Goulbi’N Maradi aquifer exhibits continuous piezometry,characterized by a general flow pattern from south to northwest and a relatively strong hydraulic gradient in the southern part,indicating recharge from recent infiltration of rain and floodwaters.The water balances calculated at a monthly time step showed that only July and August had surpluses,with average infiltrations of 25.4 mm and 23.9 mm for 2018 and an RFU of 50 mm.For 2021,the average infiltrations were 30.8 mm and 6.6 mm,respectively,for August and September,and for the same RFU.The water conductivity values between 115 and 800μS·cm^(-1).The hydrogen potential varied between 5 and 7 pH units,giving the water an acidic character that makes it corrosive to equipment.展开更多
Traditional in situ biogeochemical transformation suffers from competition among crucial microorganisms and inadequate formation of reactive minerals,thus leading to the accumulation of toxic intermediates.In this stu...Traditional in situ biogeochemical transformation suffers from competition among crucial microorganisms and inadequate formation of reactive minerals,thus leading to the accumulation of toxic intermediates.In this study,three regulation schemes were proposed to solve these problems from the perspective of engineering mode.Results showed intermittent injection mode effectively reduced the accumulation of toxic intermediates but the reduction rate of tetrachloroethylene was decreased.And periodical supplementation of carbon and sulfur sources accelerated the removal of tetrachloroethylene but failed to reduce the accumulation of toxic products.While,regular supplementation of sulfate effectively weakened the competition of methanogens and increased the iron sulfide proportion on the surface of the minerals,thus reducing the accumulation of toxicity.Based on the results,this study obtained an effective engineering approach for practical site application.In addition,the main forms of active minerals capable ofβ-eliminating contaminants during biogeochemical transformation were identified in this study,including FeS,FeS_(2),and Fe_(3)S_(4).Furthermore,the engineered regulatory mechanism of this study was summarized through the analysis of microbial community structure and mineral morphology.The amendment promotes the production of minerals and thus controls the transformation pathway of contaminants by altering the abundance of sulfate-reducing bacteria and dissimilatory iron reducing bacteria.This mechanism can provide a basis for subsequent theoretical studies.展开更多
This research examines the hard-rock aquifer system within the Nagavathi River Basin(NRB)South India,by evaluating seasonal fluctuations in groundwater composition during the pre-monsoon(PRM)and post-monsoon(POM)perio...This research examines the hard-rock aquifer system within the Nagavathi River Basin(NRB)South India,by evaluating seasonal fluctuations in groundwater composition during the pre-monsoon(PRM)and post-monsoon(POM)periods.Seasonal variations significantly influence the groundwater quality,particularly fluoride(F−)concentrations,which can fluctuate due to changes in recharge,evaporation,and anthropogenic activities.This study assesses the dynamics of F−levels in PRM and POM seasons,and identifies elevated health risks using USEPA guidelines and Monte Carlo Simulations(MCS).Groundwater in the study area exhibits alkaline pH,with NaCl and Ca-Na-HCO_(3) facies increasing in the POM season due to intensified ion exchange and rock-water interactions,as indicated in Piper and Gibb’s diagrams.Correlation and dendrogram analyses indicate that F−contamination is from geogenic and anthropogenic sources.F−levels exceed the WHO limit(1.5 mg/L)in 51 PRM and 28 POM samples,affecting 371.74 km^(2) and 203.05 km^(2),respectively.Geochemical processes,including mineral weathering,cation exchange,evaporation,and dilution,are identified through CAI I&II.Health risk assessments reveal that HQ values>1 in 78%of children,73%of teens,and 68%of adults during PRM,decreasing to 45%,40%,and 38%,respectively,in POM.MCS show maximum HQ values of 5.67(PRM)and 4.73(POM)in children,with all age groups facing significant risks from fluoride ingestion.Managed Aquifer Recharge(MAR)is recommended in this study to minimize F−contamination,ensuring safe drinking water for the community.展开更多
Geological sequestration of carbon dioxide(CO_(2))entails the long-term storage of captured emissions from CCUS(Carbon Capture,Utilization,and Storage)facilities in deep saline aquifers to mitigate greenhouse gas accu...Geological sequestration of carbon dioxide(CO_(2))entails the long-term storage of captured emissions from CCUS(Carbon Capture,Utilization,and Storage)facilities in deep saline aquifers to mitigate greenhouse gas accumulation.Among various trapping mechanisms,dissolution trapping is particularly effective in enhancing storage security.However,the stratified structure of saline aquifers plays a crucial role in controlling the efficiency of CO_(2) dissolution into the resident brine.In this study,a two-dimensional numerical model of a stratified saline aquifer is developed,integrating both two-phase flow and mass transfer dynamics.The model captures the temporal evolution of gas saturation,reservoir pressure,and CO_(2) dissolution behavior under varying geological and operational conditions.Specifically,the effects of porosity heterogeneity,permeability distribution,and injection rate on the dissolution process are examined,and sequestration efficiencies across distinct stratigraphic layers are compared.Simulation results reveal that in the early phase of CO_(2) injection,the plume spreads radially along the lower portion of the aquifer.With continued injection,high-saturation regions expand upward and eventually accumulate beneath the shale and caprock layers.Pressure within the reservoir rises in response to CO_(2) injection,propagating both vertically and laterally.CO_(2) migration and dissolution are strongly influenced by reservoir properties,with progressive dissolution occurring in the pore spaces of individual layers.High-porosity zones favor CO_(2) accumulation and enhance local dissolution,whereas low-porosity regions facilitate vertical diffusion.An increase in porosity from 0.25 to 0.30 reduces the radial extent of dissolution in the high-permeability layer by 16.5%.Likewise,increasing permeability promotes radial dispersion;each 10 mD increment extends the CO_(2) dissolution front by approximately 18 m.Elevated injection rates intensify both vertical and lateral plume migration:every 0.25×10^(−6) m/s increase in rate yields an average 100–120 m increase in radial dissolution distance within high-permeability zones.展开更多
Doline susceptibility mapping(DSM)in karst aquifer is important in terms of estimating the vulnerability of the aquifer to pollutants,estimating the infiltration rate,and infrastructures exposed to the development of ...Doline susceptibility mapping(DSM)in karst aquifer is important in terms of estimating the vulnerability of the aquifer to pollutants,estimating the infiltration rate,and infrastructures exposed to the development of dolines.In this research,doline susceptibility map was prepared in Saldaran mountain by generalized linear model(GLM)using 14 affecting parameters extracted from satellite images,digital elevation model,and geology map.Only 8 parameters have been inputted to the model which had correlation with dolines.In this regards,306 dolines were identified by the photogrammetric Unmanned Aerial Vehicles(UAV)method in 600 hectares of Salderan lands and then,these data were divided into the training(70%)and testing(30%)data for modelling.The results of DSM modeling showed that classified probability of doline occurrences in the Saldaran mountain were as follow:16.5%of the area high to very high,72%in the class of low to very low,and 5%in the moderate class.Also,locally,in Saldaran mountain,the Pirghar aquifer has the highest potential for the doline development,followed by Bagh Rostam and Sarab aquifers.Also,the precipitation,digital elevation model,Topographic Position Index,drainage density,slope,TRASP(transformed the circular aspect to a radiation index),Snow-Covered Days and vegetation cover index are of highest importance in the DSM modeling,respectively.Accurate evaluation of the model using the Receiver Operating Characteristics(ROC)curve represents a very good accuracy(AUC=0.953)of the DSM model.展开更多
Groundwater resources occur in a multi aquifer system in the alluvial coastal plain near Beihai, China. The aquifers receive recharge from precipitation, canal and reservoir infiltration, and discharge through subter...Groundwater resources occur in a multi aquifer system in the alluvial coastal plain near Beihai, China. The aquifers receive recharge from precipitation, canal and reservoir infiltration, and discharge through subterranean drainage into the sea and through artificial pumping. A quasi three dimensional finite element model has been used to simulate the spatial and temporal distribution of groundwater levels in the aquifers. Various input parameters were considered in the simulation model. A linear optimization model has been developed for groundwater development within the coastal aquifers. The objective function of the model is to maximize the total groundwater pumpage from the confined aquifer. The control of sea water intrusion is examined by the restriction of the water levels at points along the coast and of the pumping rates in coastal management cells. The response matrix used in the optimization model was generated from the simulation model by forecasting drawdown produced by pumping at a unit impulse discharge. Groundwater development can be primarily optimized by the alteration of the pumping rates of the existing wells.展开更多
The relevance of groundwater hydrogeochemistry to explain the occurrence and distribution of arsenic in groundwater is of great interest.The insightful discussions on the control of shallow groundwater(<50 m)hydrog...The relevance of groundwater hydrogeochemistry to explain the occurrence and distribution of arsenic in groundwater is of great interest.The insightful discussions on the control of shallow groundwater(<50 m)hydrogeochemistry in arsenic mobilization are known to be a viable tool to explain the arsenic menace in shallow groundwater.The present investigation emphasizes the hydrogeochemical driver and/or control over the reductive dissolution of Fe-bearing host minerals and thereby releasing arsenic into the shallow groundwater of the study area.The study suggests that hydrogeochemical evolution is mainly governed by carbonate minerals dissolution,silicate weathering,and competitive ion-exchange processes in the shallow aquifers(<50 m).The present study also indicates the prevalence of carbonate minerals dissolution over silicate weathering.The emergence of Cl^(-)concentration in the shallow groundwater founds the possibilities of anthropogenic inputs into the shallow aquifers(<50 m).The reducing environment in shallow aquifers(<50 m)of the study area is evident in the reductive dissolution of Febearing shallow aquifer minerals which absorb arsenic in the solid phase and mobilize arsenic onto shallow groundwater.The study opted for many statistical approaches to delineate the correlation among major and minor ionic constituents of the groundwater which are very helpful to understand the comprehensive mechanism of arsenic mobilization into shallow groundwater.展开更多
It is a huge reserve in South America region and it is considered one of the largest sources of groundwater on the planet. The GAS has strategic value for its countries, especially in a context of increasing scarcity....It is a huge reserve in South America region and it is considered one of the largest sources of groundwater on the planet. The GAS has strategic value for its countries, especially in a context of increasing scarcity. Its size, its physical and political complexity, as well as its “invisibility” and insufficient treatment in the international scenario, constitute some of the challenging elements for management. The article will, in the first instance, summarize the management cases for transboundary aquifers in the world. Subsequently, a physical and political characterization of the GAS will be made, so that, finally, the existing challenges for the management of this resource will be presented. In order to carry out this work, a bibliographical review of the articles and documents published in recent years concerning the management of transboundary aquifers in the world was carried out, as was done with respect to the Guarani Aquifer and its international framework.展开更多
Plinian pumice fall from the Holocene eruption of Mount Mazama in the Cascade volcanic arc is an unconfined, perched aquifer in south-central Oregon. The pumice aquifer provides near-surface groundwater storage that m...Plinian pumice fall from the Holocene eruption of Mount Mazama in the Cascade volcanic arc is an unconfined, perched aquifer in south-central Oregon. The pumice aquifer provides near-surface groundwater storage that maintains biologically diverse wetland environments. Wetland environments reflect post-eruption disruption of the once uniform pumice blanket by fluvial and lacustrine processes operating within the template of the pre-eruption landscape. In the 8.6 km<sup>2</sup> Round Meadow watershed the pumice aquifer interacts with a seasonally flooded meadow, fen, springs, and perennial stream. The laterally uniform, isotropic pumice aquifer is disrupted by flat-bottomed ephemeral stream valleys that drain to the seasonally flooded meadow. Surface water levels in the seasonally flooded meadow are controlled by a knickpoint developed on bedrock. The underlying aquifer is confined by a layer of glass-rich diatomaceous silt grading upward to organic-rich silt. Here, the aquifer is comprised of remnants of the pumice deposit, lag sand, and reworked pumice. The water level in the confined aquifer is maintained by recharge from the unconfined pumice aquifer following flow pathways beneath ephemeral stream valleys. The fen is developed on a down-thrown block of welded tuff and pre-eruption diatomaceous silt. Water levels in the fen are sensitive to inter-annual variations in precipitation. Low discharge, low temperature (5.0°C to 6.5°C), and low conductivity (30 to 50 μS/cm) springs appear to be fracture controlled and rising through welded tuff. Spring discharge and seepage through pumice from the welded tuff support perennial flow in the creek that also carries discharge from the seasonally flooded meadow when water levels are high enough to cross the knickpoint.展开更多
Groundwater is of fundamental significance for human society,especially in semi-arid areas in China.However,due to the fast social and economic development,China has been suffering from the shortage of water resource....Groundwater is of fundamental significance for human society,especially in semi-arid areas in China.However,due to the fast social and economic development,China has been suffering from the shortage of water resource.In this situation,managed aquifer recharge(MAR)was considered to be an effective measure for the sustainable management of groundwater resources.Since 1960 s,China successfully implemented many MAR schemes for different purposes such as restoration of groundwater tables,prevention of seawater intrusion,increasing urban water supplies and controlling land subsidence.From those successful experiences China developed a scientific and applicable system to implement MAR project.However,there were still many challenges in this field,for example,treated waste water had been barely used for recharge.The present review summarized the achievements in MAR applications in China as well as the associated challenges within the past 55 years before the year 2016.展开更多
The present paper provides evidence of the possible impact of shale-limestone-mudstone successions aquifers on groundwater chemistry by assessing the different hydrogeochemical processes. This was done by considering ...The present paper provides evidence of the possible impact of shale-limestone-mudstone successions aquifers on groundwater chemistry by assessing the different hydrogeochemical processes. This was done by considering a sedimentary aquifer basin, namely the Hantebet sub basin (24.4 km<sup>2</sup>), Tekeze basin, northern Ethiopia. Groundwater is the main source of water supply in the sub basin extracted using hand dug wells, for domestic, irrigation and livestock uses. The sub basin is dominated by Paleozoic-Mesozoic sedimentary successions. Twenty groundwater samples were collected from hand dug wells using depth-integrated sampling techniques from both confined and unconfined aquifers. The major water bearing formations are gravely sand, weathered shale and weathered and fractured limestone, and intercalated weathered and fractured limestone and mudstone. The results indicate that groundwater is acidic to neutral, fresh, and hard to very hard. Ca<sup>2+</sup>, Na<sup>+</sup>, HCO<sup>-</sup>3</sub> and SO<sup>2-</sup>4</sub> are dominant ions compared to Mg<sup>2+</sup>, K<sup>+</sup>, and Cl<sup>-</sup> ions which show low to very low concentrations. Among eight hydrochemical facies identified, Ca-Na-HCO<sub>3</sub> (40%), Ca-HCO<sub>3</sub> (20%), Ca-Mg-Na-HCO<sub>3</sub> (10%) and Ca-Na-HCO<sub>3</sub>-SO<sub>4</sub> (10%) types dominate water chemistry. Dissolution of calcite and gypsum, and hydrolysis of feldspars, plagioclase, biotite and pyroxene are the major geochemical processes that control the chemistry of groundwater in the area. The intercalated shale beds are the source of sodium and chloride ions. Since, this study is based on groundwater from hand dug wells, the conclusions of this study should be further verified using groundwater from deep wells that are drilled in these successions.展开更多
Estimating and studying groundwater recharge is necessary and important for the management of water resources.The main aim of this work is to estimate the value of the annual recharge in some parts of the Kermanshah a...Estimating and studying groundwater recharge is necessary and important for the management of water resources.The main aim of this work is to estimate the value of the annual recharge in some parts of the Kermanshah and Kurdistan province located in the west of Iran.There are many approaches available for estimation of the recharge,but RS(remote sensing)and GIS(geographic information system)have provided and combined a lot of effective spatial and temporal data of large areas within a short time.For this purpose,nine information layers including the slope,aspect of slope,lithology,lineament density,drainage density,precipitation,vegetation density,soil cover,and karst features were prepared and imported to the ArcMap software.After preparing the information layers,they have to weigh based on their effects on the value of the recharge.In order to be weighted the different parameters,methods of judgment expert,reciprocal influences of parameters,and AHP were used.Using GIS,the results obtained from the final map indicated the average value for the recharge based on the average calculated coefficient of recharge.The annual recharge coefficient in the study area was estimated to be between 30%and 80%.展开更多
Storage of CO2 in saline aquifers is a viable option for reducing the amount of CO2 released to the atmosphere. This paper provides an overall review of CO2 sequestration in saline aquifers. First, the principles of C...Storage of CO2 in saline aquifers is a viable option for reducing the amount of CO2 released to the atmosphere. This paper provides an overall review of CO2 sequestration in saline aquifers. First, the principles of CO2 sequestration are presented, including CO2 phase behavior, CO2-water-rock interaction, and CO2 trapping mechanisms. Then storage capacity and CO2 injectivity are discussed as the main determinants of the storage potential of saline aquifers. Next, a site section process is addressed considering basin characteristics, reservoir characteristics, and economic and social concerns. Three main procedures are then presented to investigate the suitability of a site for CO2 sequestration, including site screening, detailed site characterization, and pilot field-scale test. The methods for these procedures are also presented, such as traditional site characterization methods, laboratory experiments, and numerical simulation. Finally, some operational aspects of sequestration are discussed, including well type, injection rate, CO2 purity, and injection strategy.展开更多
Rare earth element （REE） concentrations of two different types of groundwaters （high SO42–water-SW and high alkaline waterCW） from coal bearing aquifer （–400~–280 m） in Renlou coal mine,northern Anhui Provinc...Rare earth element （REE） concentrations of two different types of groundwaters （high SO42–water-SW and high alkaline waterCW） from coal bearing aquifer （–400~–280 m） in Renlou coal mine,northern Anhui Province,China were measured.The results indicated that they had different REE characteristics： the total concentrations of REEs （ΣREE） of SW were lower than those of CW in general although they all had heavy REEs enriched relative to light REEs.The dissolved REE inorganic species of SW included Ln3＋,LnCO3＋,LnSO4＋,Ln（CO3）2– and Ln（SO4）2–,whereas the CW are Ln（CO3）2– and LnCO3＋ dominant,and the proportions of Ln（CO3）2– increased while other species decreased with pH increasing.Combined with correlation analysis,the enrichment and fractionation of SW （low alkaline water） were considered to be affected by alkaline concentrations via affecting the types and proportions of REE inorganic species.However,the effect of alkaline concentrations to the enrichment and fractionation of REEs of CW （high alkaline water） was less important than total dissolved solids and pH,which reflected the contribution from different rocks they flowed over,different degrees of water-rock interactions and/or REE solid-liquid partition coefficients.展开更多
In this paper, a combination of field measurement, theoretical analysis and numerical simulation were used to study the main control factors of coal mine water inrush in a main aquifer coal seam and its control scheme...In this paper, a combination of field measurement, theoretical analysis and numerical simulation were used to study the main control factors of coal mine water inrush in a main aquifer coal seam and its control scheme. On the basis of revealing and analyzing the coal seam as the main aquifer in western coal mine of Xiao Jihan coal mine, the simulation software of PHASE-2D was applied to analyze the water inflow under different influencing factors. The results showed that water inflow increases logarithmically with the coal seam thickness, increases as a power function with the permeability coefficient of the coal seam, and increases linearly with the coal seam burial depth and the head pressure; The evaluation model for the factors of coal seam water inrush was gained by using nonlinear regression analysis with SPSS. The mine water inrush risk evaluation partition within the scope of the mining field was obtained,through the engineering application in Xiao Jihan coal mine. To ensure the safe and efficient production of the mine, we studied the coal mine water disaster prevention and control measures of a main aquifer coal seam in aspects of roadway driving and coal seam mining.展开更多
文摘The Gabes aquifer system,located in southeastern Tunisia,is a crucial resource for supporting local socio-economic activities.Due to its dual porosity structure,is particularly vulnerable to pollution.This study aims to develop a hybrid model that combines the Fracture Aquifer Index(FAI)with the conventional GOD(Groundwater occurrence,Overall lithology,Depth to water table)method,to assess groundwater vulnerability in fractured aquifer.To develop the hybrid model,the classical GOD method was integrated with FAI to produce a single composite index.Each parameter within both GOD and FAI was scored,and a final index was calculated to delineate vulnerable areas.The results show that the study area can be classified into four vulnerability levels:Very low,low,moderate,and high,indicating that approximately 8%of the area exhibits very low vulnerability,29%has low vulnerability,25%falls into the moderate category,and 38%is considered highly vulnerable.The FAI-GOD model further incorporates fracture network characteristics.This refinement reduces the classification to three vulnerability classes:Low,medium,and high.The outcomes demonstrate that 46%of the area is highly vulnerable due to a dense concentration of fractures,while 17%represents an intermediate zone characterized by either shallow or deeper fractures.In contrast,37%corresponds to areas with lightly fractured rock,where the impact on vulnerability is minimal.Multivariate statistical analysis was employed using Principal Components Analysis(PCA)and Hierarchical Cluster Analysis(HCA)on 24 samples across six variables.The first three components account for over 76%of the total variance,reinforcing the significance of fracture dynamics in classifying vulnerability levels.The FAI-GOD model removes the very-low-vulnerability class and expands the spatial extent of low-and high-vulnerability zones,reflecting the dominant influence of fracture networks on aquifer sensitivity.While both indices use a five-class system,FAI-GOD redistributes vulnerability by eliminating very-low-vulnerability areas and amplifying low/high categories,highlighting the critical role of fractures.A strong correlation(R2=0.94)between the GOD and FAI-GOD indices,demonstrated through second-order polynomial regression,confirms the robustness of the FAI-GOD model in accurately predicting vulnerability to pollution.This model provides a useful framework for assessing the vulnerability of complex aquifers and serves as a decision-making tool for groundwater managers in similar areas.
基金The authors would like to acknowledge the grant of fellowship(DST/TMD/EWO/2K21/ACT/2021/02(G))under Project SHARP,received from the Department of Science and Technology,Government of India.
文摘One of the pathways to attain NET ZERO is CO_(2)injection into deep saline aquifers(DSAs),which alters the saturation and pore pressure of the reservoir rocks,hence the effective stress,sʹ.This,in turn,would change their geomechanical(i.e.peak deviatoric stress,elastic modulus,Poisson's ratio)and petrophysical(porosity and permeability)properties.Such a situation might trigger geo-hazards,like induced seismicity,ground deformation,caprock failure.Hence,reducing the risk of such hazards necessitates quantifying the spatial and temporal changes in sʹ,under specific CO_(2)and/or brine saturation,designated as S_(CO2)and S_(b),respectively,and resultant pore pressure.With this in view,a conceptual model depicting the reservoir,demarcated by five zones based on variations in saturation,pore-pressure,temperature,etc.,and the corresponding effective stress equations have been proposed based on the available literature.Furthermore,a critical review of literature has been carried out to decipher the limitations and contradictions associated with the findings from(i)laboratory studies to estimate S_(CO2)employing pwave velocity and electrical resistivity,(ii)analytical and numerical approaches for estimating the variation of pore-pressure in the reservoir rocks,and(iii)laboratory studies on variation in geomechanical and petrophysical properties under the conditions representative of the above-mentioned zones of the conceptual model.The authors consider that extensive experiments should be conducted on the rocks from different sources and tested under various conditions of the CO_(2)injection to validate the proposed model for the execution of risk-free CO_(2)storage in DSAs.
文摘Groundwater quality is pivotal for sustainable resource management,necessitating comprehen-sive investigation to safeguard this critical resource.This study introduces a novel methodology that inte-grates stiff diagrams,geostatistical analysis,and geometric computation to delineate the extent of a confined aquifer within the Chahrdoly aquifer,located west of Hamadan,Iran.For the first time,this approach combines these tools to map the boundaries of a confined aquifer based on hydrochemical characteristics.Stiff diagrams were used to calculate geometric parameters from groundwater chemistry data,followed by simulation using a linear model incorporating the semivariogram parameterγ(h).The Root Mean Square Error(RMSE)of the linear model was used to differentiate confined from unconfined aquifers based on hydrochemical signatures.Validation was conducted by generating a cross-sectional hydrogeological layer from well logs,confirming the presence of aquitard layers.The results successufully delineated the confined aquifer's extent,showing strong agreement with hydrogeological log data.By integrating stiff diagrams with semivariogram analysis,this study enhances the understanding of hydrochemical processes,offering a robust framework for groundwater resource identification and management.
文摘In the Maradi region,the alluvial aquifer of the Goulbi’N Maradi rests on the aquifers of the Continental Hamadien.It represents an essential reserve for irrigation and drinking water supply.However,due to its high demand and the excessive use of chemical fertilizers and pesticides in irrigation,a ten-year analysis of the dynamics of this alluvial aquifer has proven necessary.Hence,this study,based on hydrodynamic and hydrochemical approaches,aims to improve knowledge of the dynamics of the alluvial aquifer from 2015 to 2023.The novelty of this study lies in its comprehensive coverage of the entire Goulbi N’Maradi valley in Niger,employing a multidimensional approach.The data used were composed of water samples taken from forty-five structures,piezometric monitoring sheets,and digital terrain models.The results reveal that the Goulbi’N Maradi aquifer exhibits continuous piezometry,characterized by a general flow pattern from south to northwest and a relatively strong hydraulic gradient in the southern part,indicating recharge from recent infiltration of rain and floodwaters.The water balances calculated at a monthly time step showed that only July and August had surpluses,with average infiltrations of 25.4 mm and 23.9 mm for 2018 and an RFU of 50 mm.For 2021,the average infiltrations were 30.8 mm and 6.6 mm,respectively,for August and September,and for the same RFU.The water conductivity values between 115 and 800μS·cm^(-1).The hydrogen potential varied between 5 and 7 pH units,giving the water an acidic character that makes it corrosive to equipment.
基金supported by the National Natural Science Foundation of China(No.42277057).
文摘Traditional in situ biogeochemical transformation suffers from competition among crucial microorganisms and inadequate formation of reactive minerals,thus leading to the accumulation of toxic intermediates.In this study,three regulation schemes were proposed to solve these problems from the perspective of engineering mode.Results showed intermittent injection mode effectively reduced the accumulation of toxic intermediates but the reduction rate of tetrachloroethylene was decreased.And periodical supplementation of carbon and sulfur sources accelerated the removal of tetrachloroethylene but failed to reduce the accumulation of toxic products.While,regular supplementation of sulfate effectively weakened the competition of methanogens and increased the iron sulfide proportion on the surface of the minerals,thus reducing the accumulation of toxicity.Based on the results,this study obtained an effective engineering approach for practical site application.In addition,the main forms of active minerals capable ofβ-eliminating contaminants during biogeochemical transformation were identified in this study,including FeS,FeS_(2),and Fe_(3)S_(4).Furthermore,the engineered regulatory mechanism of this study was summarized through the analysis of microbial community structure and mineral morphology.The amendment promotes the production of minerals and thus controls the transformation pathway of contaminants by altering the abundance of sulfate-reducing bacteria and dissimilatory iron reducing bacteria.This mechanism can provide a basis for subsequent theoretical studies.
文摘This research examines the hard-rock aquifer system within the Nagavathi River Basin(NRB)South India,by evaluating seasonal fluctuations in groundwater composition during the pre-monsoon(PRM)and post-monsoon(POM)periods.Seasonal variations significantly influence the groundwater quality,particularly fluoride(F−)concentrations,which can fluctuate due to changes in recharge,evaporation,and anthropogenic activities.This study assesses the dynamics of F−levels in PRM and POM seasons,and identifies elevated health risks using USEPA guidelines and Monte Carlo Simulations(MCS).Groundwater in the study area exhibits alkaline pH,with NaCl and Ca-Na-HCO_(3) facies increasing in the POM season due to intensified ion exchange and rock-water interactions,as indicated in Piper and Gibb’s diagrams.Correlation and dendrogram analyses indicate that F−contamination is from geogenic and anthropogenic sources.F−levels exceed the WHO limit(1.5 mg/L)in 51 PRM and 28 POM samples,affecting 371.74 km^(2) and 203.05 km^(2),respectively.Geochemical processes,including mineral weathering,cation exchange,evaporation,and dilution,are identified through CAI I&II.Health risk assessments reveal that HQ values>1 in 78%of children,73%of teens,and 68%of adults during PRM,decreasing to 45%,40%,and 38%,respectively,in POM.MCS show maximum HQ values of 5.67(PRM)and 4.73(POM)in children,with all age groups facing significant risks from fluoride ingestion.Managed Aquifer Recharge(MAR)is recommended in this study to minimize F−contamination,ensuring safe drinking water for the community.
基金supported by the National Natural Science Foundation of China(No.52306187)the Fundamental Research Funds for the Central Universities of China(Grant No.3132024205)the Open Fund of Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education(Grant No.LOEC-202004).
文摘Geological sequestration of carbon dioxide(CO_(2))entails the long-term storage of captured emissions from CCUS(Carbon Capture,Utilization,and Storage)facilities in deep saline aquifers to mitigate greenhouse gas accumulation.Among various trapping mechanisms,dissolution trapping is particularly effective in enhancing storage security.However,the stratified structure of saline aquifers plays a crucial role in controlling the efficiency of CO_(2) dissolution into the resident brine.In this study,a two-dimensional numerical model of a stratified saline aquifer is developed,integrating both two-phase flow and mass transfer dynamics.The model captures the temporal evolution of gas saturation,reservoir pressure,and CO_(2) dissolution behavior under varying geological and operational conditions.Specifically,the effects of porosity heterogeneity,permeability distribution,and injection rate on the dissolution process are examined,and sequestration efficiencies across distinct stratigraphic layers are compared.Simulation results reveal that in the early phase of CO_(2) injection,the plume spreads radially along the lower portion of the aquifer.With continued injection,high-saturation regions expand upward and eventually accumulate beneath the shale and caprock layers.Pressure within the reservoir rises in response to CO_(2) injection,propagating both vertically and laterally.CO_(2) migration and dissolution are strongly influenced by reservoir properties,with progressive dissolution occurring in the pore spaces of individual layers.High-porosity zones favor CO_(2) accumulation and enhance local dissolution,whereas low-porosity regions facilitate vertical diffusion.An increase in porosity from 0.25 to 0.30 reduces the radial extent of dissolution in the high-permeability layer by 16.5%.Likewise,increasing permeability promotes radial dispersion;each 10 mD increment extends the CO_(2) dissolution front by approximately 18 m.Elevated injection rates intensify both vertical and lateral plume migration:every 0.25×10^(−6) m/s increase in rate yields an average 100–120 m increase in radial dissolution distance within high-permeability zones.
文摘Doline susceptibility mapping(DSM)in karst aquifer is important in terms of estimating the vulnerability of the aquifer to pollutants,estimating the infiltration rate,and infrastructures exposed to the development of dolines.In this research,doline susceptibility map was prepared in Saldaran mountain by generalized linear model(GLM)using 14 affecting parameters extracted from satellite images,digital elevation model,and geology map.Only 8 parameters have been inputted to the model which had correlation with dolines.In this regards,306 dolines were identified by the photogrammetric Unmanned Aerial Vehicles(UAV)method in 600 hectares of Salderan lands and then,these data were divided into the training(70%)and testing(30%)data for modelling.The results of DSM modeling showed that classified probability of doline occurrences in the Saldaran mountain were as follow:16.5%of the area high to very high,72%in the class of low to very low,and 5%in the moderate class.Also,locally,in Saldaran mountain,the Pirghar aquifer has the highest potential for the doline development,followed by Bagh Rostam and Sarab aquifers.Also,the precipitation,digital elevation model,Topographic Position Index,drainage density,slope,TRASP(transformed the circular aspect to a radiation index),Snow-Covered Days and vegetation cover index are of highest importance in the DSM modeling,respectively.Accurate evaluation of the model using the Receiver Operating Characteristics(ROC)curve represents a very good accuracy(AUC=0.953)of the DSM model.
基金This paper is partially supported by the Fund for Young Geologists in the Ministry of Geology and Mineral Resources of China(
文摘Groundwater resources occur in a multi aquifer system in the alluvial coastal plain near Beihai, China. The aquifers receive recharge from precipitation, canal and reservoir infiltration, and discharge through subterranean drainage into the sea and through artificial pumping. A quasi three dimensional finite element model has been used to simulate the spatial and temporal distribution of groundwater levels in the aquifers. Various input parameters were considered in the simulation model. A linear optimization model has been developed for groundwater development within the coastal aquifers. The objective function of the model is to maximize the total groundwater pumpage from the confined aquifer. The control of sea water intrusion is examined by the restriction of the water levels at points along the coast and of the pumping rates in coastal management cells. The response matrix used in the optimization model was generated from the simulation model by forecasting drawdown produced by pumping at a unit impulse discharge. Groundwater development can be primarily optimized by the alteration of the pumping rates of the existing wells.
文摘The relevance of groundwater hydrogeochemistry to explain the occurrence and distribution of arsenic in groundwater is of great interest.The insightful discussions on the control of shallow groundwater(<50 m)hydrogeochemistry in arsenic mobilization are known to be a viable tool to explain the arsenic menace in shallow groundwater.The present investigation emphasizes the hydrogeochemical driver and/or control over the reductive dissolution of Fe-bearing host minerals and thereby releasing arsenic into the shallow groundwater of the study area.The study suggests that hydrogeochemical evolution is mainly governed by carbonate minerals dissolution,silicate weathering,and competitive ion-exchange processes in the shallow aquifers(<50 m).The present study also indicates the prevalence of carbonate minerals dissolution over silicate weathering.The emergence of Cl^(-)concentration in the shallow groundwater founds the possibilities of anthropogenic inputs into the shallow aquifers(<50 m).The reducing environment in shallow aquifers(<50 m)of the study area is evident in the reductive dissolution of Febearing shallow aquifer minerals which absorb arsenic in the solid phase and mobilize arsenic onto shallow groundwater.The study opted for many statistical approaches to delineate the correlation among major and minor ionic constituents of the groundwater which are very helpful to understand the comprehensive mechanism of arsenic mobilization into shallow groundwater.
文摘It is a huge reserve in South America region and it is considered one of the largest sources of groundwater on the planet. The GAS has strategic value for its countries, especially in a context of increasing scarcity. Its size, its physical and political complexity, as well as its “invisibility” and insufficient treatment in the international scenario, constitute some of the challenging elements for management. The article will, in the first instance, summarize the management cases for transboundary aquifers in the world. Subsequently, a physical and political characterization of the GAS will be made, so that, finally, the existing challenges for the management of this resource will be presented. In order to carry out this work, a bibliographical review of the articles and documents published in recent years concerning the management of transboundary aquifers in the world was carried out, as was done with respect to the Guarani Aquifer and its international framework.
文摘Plinian pumice fall from the Holocene eruption of Mount Mazama in the Cascade volcanic arc is an unconfined, perched aquifer in south-central Oregon. The pumice aquifer provides near-surface groundwater storage that maintains biologically diverse wetland environments. Wetland environments reflect post-eruption disruption of the once uniform pumice blanket by fluvial and lacustrine processes operating within the template of the pre-eruption landscape. In the 8.6 km<sup>2</sup> Round Meadow watershed the pumice aquifer interacts with a seasonally flooded meadow, fen, springs, and perennial stream. The laterally uniform, isotropic pumice aquifer is disrupted by flat-bottomed ephemeral stream valleys that drain to the seasonally flooded meadow. Surface water levels in the seasonally flooded meadow are controlled by a knickpoint developed on bedrock. The underlying aquifer is confined by a layer of glass-rich diatomaceous silt grading upward to organic-rich silt. Here, the aquifer is comprised of remnants of the pumice deposit, lag sand, and reworked pumice. The water level in the confined aquifer is maintained by recharge from the unconfined pumice aquifer following flow pathways beneath ephemeral stream valleys. The fen is developed on a down-thrown block of welded tuff and pre-eruption diatomaceous silt. Water levels in the fen are sensitive to inter-annual variations in precipitation. Low discharge, low temperature (5.0°C to 6.5°C), and low conductivity (30 to 50 μS/cm) springs appear to be fracture controlled and rising through welded tuff. Spring discharge and seepage through pumice from the welded tuff support perennial flow in the creek that also carries discharge from the seasonally flooded meadow when water levels are high enough to cross the knickpoint.
基金supported by German Federal Ministry of Education and Research(BMBF),project number 01LN1311A。
文摘Groundwater is of fundamental significance for human society,especially in semi-arid areas in China.However,due to the fast social and economic development,China has been suffering from the shortage of water resource.In this situation,managed aquifer recharge(MAR)was considered to be an effective measure for the sustainable management of groundwater resources.Since 1960 s,China successfully implemented many MAR schemes for different purposes such as restoration of groundwater tables,prevention of seawater intrusion,increasing urban water supplies and controlling land subsidence.From those successful experiences China developed a scientific and applicable system to implement MAR project.However,there were still many challenges in this field,for example,treated waste water had been barely used for recharge.The present review summarized the achievements in MAR applications in China as well as the associated challenges within the past 55 years before the year 2016.
文摘The present paper provides evidence of the possible impact of shale-limestone-mudstone successions aquifers on groundwater chemistry by assessing the different hydrogeochemical processes. This was done by considering a sedimentary aquifer basin, namely the Hantebet sub basin (24.4 km<sup>2</sup>), Tekeze basin, northern Ethiopia. Groundwater is the main source of water supply in the sub basin extracted using hand dug wells, for domestic, irrigation and livestock uses. The sub basin is dominated by Paleozoic-Mesozoic sedimentary successions. Twenty groundwater samples were collected from hand dug wells using depth-integrated sampling techniques from both confined and unconfined aquifers. The major water bearing formations are gravely sand, weathered shale and weathered and fractured limestone, and intercalated weathered and fractured limestone and mudstone. The results indicate that groundwater is acidic to neutral, fresh, and hard to very hard. Ca<sup>2+</sup>, Na<sup>+</sup>, HCO<sup>-</sup>3</sub> and SO<sup>2-</sup>4</sub> are dominant ions compared to Mg<sup>2+</sup>, K<sup>+</sup>, and Cl<sup>-</sup> ions which show low to very low concentrations. Among eight hydrochemical facies identified, Ca-Na-HCO<sub>3</sub> (40%), Ca-HCO<sub>3</sub> (20%), Ca-Mg-Na-HCO<sub>3</sub> (10%) and Ca-Na-HCO<sub>3</sub>-SO<sub>4</sub> (10%) types dominate water chemistry. Dissolution of calcite and gypsum, and hydrolysis of feldspars, plagioclase, biotite and pyroxene are the major geochemical processes that control the chemistry of groundwater in the area. The intercalated shale beds are the source of sodium and chloride ions. Since, this study is based on groundwater from hand dug wells, the conclusions of this study should be further verified using groundwater from deep wells that are drilled in these successions.
文摘Estimating and studying groundwater recharge is necessary and important for the management of water resources.The main aim of this work is to estimate the value of the annual recharge in some parts of the Kermanshah and Kurdistan province located in the west of Iran.There are many approaches available for estimation of the recharge,but RS(remote sensing)and GIS(geographic information system)have provided and combined a lot of effective spatial and temporal data of large areas within a short time.For this purpose,nine information layers including the slope,aspect of slope,lithology,lineament density,drainage density,precipitation,vegetation density,soil cover,and karst features were prepared and imported to the ArcMap software.After preparing the information layers,they have to weigh based on their effects on the value of the recharge.In order to be weighted the different parameters,methods of judgment expert,reciprocal influences of parameters,and AHP were used.Using GIS,the results obtained from the final map indicated the average value for the recharge based on the average calculated coefficient of recharge.The annual recharge coefficient in the study area was estimated to be between 30%and 80%.
基金support from the China Scholarship Council ([2007]3020) is gratefully acknowledged
文摘Storage of CO2 in saline aquifers is a viable option for reducing the amount of CO2 released to the atmosphere. This paper provides an overall review of CO2 sequestration in saline aquifers. First, the principles of CO2 sequestration are presented, including CO2 phase behavior, CO2-water-rock interaction, and CO2 trapping mechanisms. Then storage capacity and CO2 injectivity are discussed as the main determinants of the storage potential of saline aquifers. Next, a site section process is addressed considering basin characteristics, reservoir characteristics, and economic and social concerns. Three main procedures are then presented to investigate the suitability of a site for CO2 sequestration, including site screening, detailed site characterization, and pilot field-scale test. The methods for these procedures are also presented, such as traditional site characterization methods, laboratory experiments, and numerical simulation. Finally, some operational aspects of sequestration are discussed, including well type, injection rate, CO2 purity, and injection strategy.
基金Project supported by the National Natural Science Foundation of China (40873015)the Eleventh Five-Year Scientific and Technological Project of Anhui Province,China (08010302062)
文摘Rare earth element （REE） concentrations of two different types of groundwaters （high SO42–water-SW and high alkaline waterCW） from coal bearing aquifer （–400~–280 m） in Renlou coal mine,northern Anhui Province,China were measured.The results indicated that they had different REE characteristics： the total concentrations of REEs （ΣREE） of SW were lower than those of CW in general although they all had heavy REEs enriched relative to light REEs.The dissolved REE inorganic species of SW included Ln3＋,LnCO3＋,LnSO4＋,Ln（CO3）2– and Ln（SO4）2–,whereas the CW are Ln（CO3）2– and LnCO3＋ dominant,and the proportions of Ln（CO3）2– increased while other species decreased with pH increasing.Combined with correlation analysis,the enrichment and fractionation of SW （low alkaline water） were considered to be affected by alkaline concentrations via affecting the types and proportions of REE inorganic species.However,the effect of alkaline concentrations to the enrichment and fractionation of REEs of CW （high alkaline water） was less important than total dissolved solids and pH,which reflected the contribution from different rocks they flowed over,different degrees of water-rock interactions and/or REE solid-liquid partition coefficients.
基金provided by the National Key Basic Research Program of China (No. 2013CB227905)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China (No. 51421003)the Jiangsu Province Ordinary University Graduate Student Scientific Research Innovation Projects (No. KYLX16_0564)
文摘In this paper, a combination of field measurement, theoretical analysis and numerical simulation were used to study the main control factors of coal mine water inrush in a main aquifer coal seam and its control scheme. On the basis of revealing and analyzing the coal seam as the main aquifer in western coal mine of Xiao Jihan coal mine, the simulation software of PHASE-2D was applied to analyze the water inflow under different influencing factors. The results showed that water inflow increases logarithmically with the coal seam thickness, increases as a power function with the permeability coefficient of the coal seam, and increases linearly with the coal seam burial depth and the head pressure; The evaluation model for the factors of coal seam water inrush was gained by using nonlinear regression analysis with SPSS. The mine water inrush risk evaluation partition within the scope of the mining field was obtained,through the engineering application in Xiao Jihan coal mine. To ensure the safe and efficient production of the mine, we studied the coal mine water disaster prevention and control measures of a main aquifer coal seam in aspects of roadway driving and coal seam mining.
