Development Of Groundwater Resources Research Articles

Hydrogeochemical process and coal mining-motivated effect on the hydrochemistry for the groundwater system in mining area of Western China

The Jurassic coalfield in the mining area of western China exhibits a multi-layered groundwater system. However, it is subject to an arid and semi-arid climate with limited water resources. Consequently, the ecological environment is highly vulnerable, and the chemistry and quality of groundwater may be influenced by multiple factors. This study systematically the coal mining-motivated effect on the hydrochemistry and water quality of the groundwater system, using the Caojiatan Coal Mine as a case study. The analysis incorporates a combination of the self-organizing maps (SOM), entropy-weighted water quality index (EWQI), and traditional hydrochemical analysis methods. After coal mining, there was an increase in the proportion of HCO3-Ca and HCO3-Mg in the groundwater samples of J2z, J2y4, and J2y5. The groundwater is controlled by cation exchange as a whole. The J2y4 and above groundwater is influenced by both the dissolution of carbonate and silicate rocks before coal mining. After coal mining, the Quaternary and J2a groundwater in the western wing is primarily influenced by the dissolution of carbonate rocks; the J2z, J2y4 and J2y5 groundwater is primarily governed by the dissolution of silicate rocks and the oxidation of FeS2; the J2y3 and below groundwater is primarily controlled by the dissolution of evaporate rocks. The resulting dilution effect after coal mining and the implementation of measures for the discharge of treated mine water make the groundwater quality of the J2y4 and higher aquifers tend to be better. The research findings serve as a valuable reference for promoting the sustainable development and protection of groundwater resources not only in the study area but also in other coal mines.

Groundwater hydrochemistry, source identification and health assessment based on self-organizing map in an intensive mining area in Shanxi, China

The Changzhi Basin in Shanxi is renowned for its extensive mining activities. It's crucial to comprehend the spatial distribution and geochemical factors influencing its water quality to uphold water security and safeguard the ecosystem. However, the complexity inherent in hydrogeochemical data presents challenges for linear data analysis methods. This study utilizes a combined approach of self-organizing maps (SOM) and K-means clustering to investigate the hydrogeochemical sources of shallow groundwater in the Changzhi Basin and the associated human health risks. The results showed that the groundwater chemical characteristics were categorized into 48 neurons grouped into six clusters (C1–C6) representing different groundwater types with different contamination characteristics. C1, C3, and C5 represent uncontaminated or minimally contaminated groundwater (Ca–HCO3 type), while C2 signifies mixed-contaminated groundwater (HCO3–Ca type, Mixed Cl–Mg–Ca type, and CaSO4 type). C4 samples exhibit impacts from agricultural activities (Mixed Cl–Mg–Ca), and C6 reflects high Ca and NO3− groundwater. Anthropogenic activities, especially agriculture, have resulted in elevated NO3− levels in shallow groundwater. Notably, heightened non-carcinogenic risks linked to NO3−, Pb, F−, and Mn exposure through drinking water, particularly impacting children, warrant significant attention. This research contributes valuable insights into sustainable groundwater resource development, pollution mitigation strategies, and effective ecosystem protection within intensive mining regions like the Changzhi Basin. It serves as a vital reference for similar areas worldwide, offering guidance for groundwater management, pollution prevention, and control.

Nitrate denitrification rate response to temperature gradient change during river bank infiltration.

Nitrate attenuation during river bank infiltration is the key process for reducing nitrogen pollution. Temperature is considered to be an important factor affecting nitrate attenuation. However, the magnitude and mechanism of its impact have not been clear for a long time. In this study, the effects of temperature and temperature gradient on the nitrate denitrification rate were investigated via static batch and dynamic soil column simulation experiments. The results showed that temperature had a significant effect on the denitrification rate. Temperature effects were first observed in denitrifying bacteria. At low temperatures, the microorganism diversity was low, resulting in a lower denitrification rate constant. The static experimental results showed that the denitrification rate at 19°C was approximately 2.4 times that at 10°C. The dynamic soil column experiment established an exponential positive correlation between the nitrate denitrification decay kinetic constant and temperature. The affinity of denitrifying enzymes for nitrate in the reaction substrate was ordered as follows: decreasing temperature gradient (30°C → 10°C) > zero temperature gradient (10°C) > increasing temperature gradient condition (0°C → 10°C). This study provides a theoretical basis for the biogeochemical processes underlying river bank infiltration, which will help aid in the development and utilization of groundwater resources.

Assessing heterogeneous groundwater systems: Geostatistical interpretation of well logging data for estimating essential hydrogeological parameters

This research presents an unsupervised learning approach for interpreting well-log data to characterize the hydrostratigraphical units within the Quaternary aquifer system in Debrecen area, Eastern Hungary. The study applied factor analysis (FA) to extract factor logs from spontaneous potential (SP), natural gamma ray (NGR), and resistivity (RS) logs and correlate it to the petrophysical and hydrogeological parameters of shale volume and hydraulic conductivity. This research indicated a significant exponential relationship between the shale volume and the scaled first factor derived through factor analysis. As a result, a universal FA-based equation for shale volume estimation is derived that shows a close agreement with the deterministic shale volume estimation. Furthermore, the first scaled factor is correlated to the decimal logarithm of hydraulic conductivity estimated with the Csókás method. Csókás method is modified from the Kozeny-Carman equation that continuously estimates the hydraulic conductivity. FA and Csókás method-based estimations showed high similarity with a correlation coefficient of 0.84. The use of factor analysis provided a new strategy for geophysical well-logs interpretation that bridges the gap between traditional and data-driven machine learning techniques. This approach is beneficial in characterizing heterogeneous aquifer systems for successful groundwater resource development.

Water Governance in Tanzania – A Synthesis of Legal and Institutional Frameworks for Groundwater Management in the Upper Great Ruaha River Catchment

The importance of groundwater resources in buffering the effects of climate change on water scarcity and security is highly acknowledged worldwide. However, groundwater development and use can only be sustainable with a more robust policy and institutional arrangements related to water governance. The purpose of this study was to analyse the legal framework of water resource development and management in order to contribute in identifying policy constraints to sustainable groundwater resource development and management in Tanzania. The paper used information from literature reviews and data collected through qualitative methods using a case study of Usangu Plains in the Upper Great Ruaha River Catchment in Tanzania. The findings reveal that water governance institutional frameworks are well structured to provide guidelines on how water as a basic human resource can be utilised and properly managed, but most importantly, these institutional arrangements place disproportionate emphasis on groundwater. Attaining sustainable groundwater development and use requires new disclosures and narratives in water policy and law, integrating both surface and groundwater resources. The weaknesses identified in groundwater governance need to be taken on Board once, the existing water institutional frameworks open to perfection for sustainable utilisation of groundwater resources

Evaluation of hydrogeochemical processes and saltwater intrusion in the coastal aquifers in the southern part of Puri District, Odisha, India.

Groundwater is widely regarded as being among the freshwater natural resources with the lowest levels of contamination. Nevertheless, the saltwater intrusion has resulted in the contamination of groundwater in coastal regions with lower elevation. The rationale of the present work is to investigate the chemistry of groundwater, to identify the various facies of groundwater, to identify the processes that influence groundwater chemistry and saltwater intrusion, and to evaluate the groundwater's aptness for use in drinking and farming. In order to gain an understanding of the groundwater quality as well as the salinization process that occurs in coastal aquifers as a result of hydrogeochemical processes, a total of 108 groundwater samples (54 each in pre- and post-monsoon) were taken and analyzed for several physiochemical parameters in the southern part of the Puri district in the Indian state of Odisha. The data has undergone analysis and examination to identify the factors (such as hydrological facies, potential solute source in water, and salinization process) that contribute to groundwater salinity. The result showed the chemistry controlling processes of rock-water interaction as per Gibbs diagram. The majority of shallow aquifers exhibit the Na-Cl type of facies as per the Piper plot. A total of 37% pre-monsoon and 33% post-monsoon samples having Na+/Cl- ratio below the threshold of 0.86 indicating the influence of saltwater intrusion. In both seasons, it was observed that 74% of the samples exhibited a Na+ concentration that exceeded the permissible limit set by the World Health Organization (WHO) for drinking purposes. The findings indicate that most groundwater failed to pass safe drinking water and irrigation standards due to saltwater intrusion. Consequently, the monitoring of coastal aquifer quality has become imperative in order to ensure the sustainability of aquifers and the development of groundwater resources. This is because coastal aquifers are highly vulnerable to saltwater intrusion, primarily as a result of the extensive extraction of groundwater for diverse purposes.

Mapping groundwater potential zone using groundwater potentiality index in Sulamu, Central Fatuleu and West Fatuleu, Kupang, East Nusa Tenggara

Water scarcity often occurs during the dry season in Kupang Regency, which is a semi-arid area. The drought limits surface water availability during the dry season, thus making groundwater one of the reliable solutions for fulfilling the need for water from springs and wells. Therefore, mapping the potential of groundwater in the research area becomes the aim of this study, which has never been conducted before. The method used in this research is the Groundwater Potentiality Index, which uses five parameters to identify groundwater potential areas: fracture, lithology, topography, drainage, and rainfall. Field observation and secondary data collection were conducted to provide those parameters. The results are groundwater potential index classified into five groundwater potential zones, resulting in very low (17.07% and 20.39% of total area), low (51.16% and 48.94% of total area), moderate (26.9% and 27.05% of total area), high (4.09% and 3.1% of total area), and very high (0.77% and 0.53% of total area). Zones of very high are found along major fault areas. Areas with high groundwater potential zones indicated favorable conditions for wells positioning at groundwater exploration. These results can be a basis for action related to groundwater resource development in the research area.

Hydrogeochemical characterization, quality assessment, and potential nitrate health risk of shallow groundwater in Dongwen River Basin, North China.

Assessing groundwater geochemical formation processes and pollution circumstances is significant for sustainable watershed management. In the present study, 58 shallow groundwater samples were taken from the Dongwen River Basin (DRB) to comprehensively assess the hydrochemical sources, groundwater quality status, and potential risks of NO3- to human health. Based on the Box and Whisker plot, the cation's concentration followed the order of Ca2+ > Mg2+ > Na+ > K+, while anions' mean levels were HCO3- > SO42- > NO3- > Cl-. The NO3- level in groundwater samples fluctuated between 4.2 and 301.3mg/L, with 67.2% of samples beyond the World Health Organization (WHO) criteria (50mg/L) for drinking. The Piper diagram indicated the hydrochemical type of groundwater and surface water were characterized as Ca·Mg-HCO3 type. Combining ionic ratio analysis with principal component analysis (PCA) results, agricultural activities contributed a significant effect on groundwater NO3-, with soil nitrogen input and manure/sewage inputs also potential sources. However, geogenic processes (e.g., carbonates and evaporite dissolution/precipitation) controlled other ion compositions in the study area. The groundwater samples with higher NO3- values were mainly found in river valley regions with intense anthropogenic activities. The entropy weight water quality index (EWQI) model identified that the groundwater quality rank ranged from excellent (70.7%) and good (25.9%) to medium (3.4%). However, the hazard quotient (HQ) used in the human health risk assessment (HHRA) model showed that above 91.38% of groundwater samples have a NO3- non-carcinogenic health risk for infants, 84.48% for children, 82.76% for females, and 72.41% for males. The findings of this study could provide a scientific basis for the rational development and usage of groundwater resources as well as for the preservation of the inhabitants' health in DRB.

Hydrochemical Characteristics and Genesis Mechanism of Groundwater in the Dry Period in the Zhangjiakou Area

In order to better support the construction of the capital water conservation functional area and ecological environment support area， research on the chemical characteristics of groundwater and its formation mechanism in the dry period in the Zhangjiakou area can provide a great reference for the rational development and utilization of groundwater resources. A total of 41 groups of groundwater samples were collected， and the hydrochemical types， composition characteristics， and control factors of groundwater in the study area were analyzed by using the combined method of descriptive statistical analysis， Piper triplot， correlation analysis， Gibbs plot， and ion ratio. The results showed that the groundwater in the study area was weakly alkaline， with the total hardness and ρ（TDS） ranging from 105.00 mg·L-1 to 1 433.00 mg·L-1 and 137.00 mg·L-1 to 2 286.00 mg·L-1， respectively. The total hardness and TDS mass concentrations of groundwater in the Bashang area were higher than those in the Baxia area. HCO3- and Na+ were the main dominant anions and cations in the groundwater in the study area. The highest overstandard rate of the main components in groundwater was that of total hardness （36.59%）. The overstandard rate and maximum excess multiple of each component in groundwater in the Bashang area were greater than those in the Baxia area. HCO3-Ca·Mg·Na was the main type of groundwater hydrochemistry in the study area， and there was little difference between the Bashang area and the Baxia area. SO42-， Cl-， HCO3-， Na+， and Mg2+ contributed the most to TDS. The chemical characteristics of groundwater were affected by weathering and filtration of rock minerals such as salt rock， albite， and dolomite； cation exchange； and human activities. Evaporative crystallization and atmospheric precipitation contributed to a small part of the main ion source of groundwater in the area. The effect of human activities on groundwater in the Bashang area was greater than that in the Baxia area， and NO3- mainly originated from agricultural activities.

Identification of high-permeability and water-rich zones in a fractured karst water source area based on the hydraulic tomography method

Determining the spatial hydraulic parameters of aquifers is of paramount importance for the development and utilization of groundwater in water source areas. However, most methods are unable to accurately characterize the heterogeneity of aquifers because of the influences of complex geology, hydrogeology, structure and insufficient information. Hydraulic tomography (HT) is an effective and robust method for hydraulic parameter inversion to characterize heterogeneity. In this study, a two-dimensional HT model was established to simulate hydraulic parameter fields for a fractured karst aquifer in the Zhangji water source area (Xuzhou city, China). Steady-state hydraulic tomography (SSHT) and transient hydraulic tomography (THT) with different prior information conditions were applied to determine the high-permeability area and water-rich zones, and to infer possible locations of karst conduits and strong runoff paths in the water source area. The results indicate that: (1) THT can better reveal larger-scale heterogeneous characteristics of hydraulic properties compared to SSHT. The hydraulic conductivity distribution estimated by THT correlates well with the geological conditions of the area, especially in identifying water-rich zones formed by faults and other formations. (2) When combined with geological conditions, HT possesses the ability to identify strong runoff paths in fractured karst aquifers. (3) Accurate prior information, which is more relevant to the head response information, is conducive to obtaining more acceptable HT results. (4) THT can simultaneously identify high-permeability and high-storage zones, and the analysis of the overlap of these two regions has the potential to predict underground water reservoirs, which is of the utmost importance for the development and utilization of groundwater resources in water source areas.

Delineation of lineaments for groundwater prospecting in hard rocks: inferences from remote sensing and geophysical data

Egypt is grappling with water scarcity challenges, which are exacerbated by extensive urban development in arid coastal regions with rugged terrain. Although desalinated water is an alternative source in the remote Halayeib region of Southeast Egypt, its cost increases reliance on groundwater from the intricate aquifers. This study aims to accurately delineate hydro-structural features, known as lineaments, and assess their impact on the groundwater conditions in this promising region. This integrated approach involves the assessment of various spaceborne sensors, including optical (Landsat 8), Digital Elevation Models (ALOS and ASTER-DEMs), and radar (Sentinel-1), using geospatial and geostatistical techniques within the Geographic Information System (GIS). Radar-based sensors, particularly the Sentinel-1A vertical–vertical (S1A VV) polarization, outperform all other datasets in extracting lineaments, yielding 4883 lineaments that correspond to the regional geological faults. These lineaments trend in NE–SW, NNE–SSW, NW–SE, and E-W directions. The results also indicated that both digital elevation models (DEMs) were less effective, showing different orientations with azimuth angles. S1A VV proved to be highly effective in identifying subsurface fractured hard rock terrains beneath thin sedimentary covers, especially in the flat coastal area of Wadi Serimatai, where they intersected natural drainage pathways. Geoelectrical sections confirmed that there are orthogonal subsurface faults extending from fractured basement aquifers to near-surface layers. These faults align with the NE-SW and NNE-SSW directions observed in S1A VV lineaments. Geostatistical analysis revealed that S1A VV structural lineaments, lithological, and hydrogeological factors influence the occurrence of groundwater. This emphasizes the structural control over groundwater and its significant impact on water flow and storage. The study provides valuable insights for groundwater management, guiding decisions related to the development of groundwater resources.

먹는 샘물에 관한 연구동향 분석

The purpose of this study was to analyze the research trends related to drinking spring water and bottled water in this study and to suggest an expanded interpretation and direction for future research. 695 papers to be analyzed were collected by the Academic Research Information Service (RISS) with the keywords of drinking spring water and bottled water, and 117 final analysis papers were selected. For this, the publication status, research field, and research topic of drinking spring water research by year were analyzed. As a result of analyzing the research trend, it was confirmed that the number of publications of papers on drinking spring water research has gradually increased since the 2010s. The mainly studied fields were divided into business administration, chemistry, and environmental fields, and as a result of confirming the topics by research field, the most frequently addressed in the business administration field was mainly research on the effect of factors such as the selection attribute of drinking spring water and brand image on purchasing behavior. In this chemical field, research was mainly conducted on the characteristics of groundwater, changes in the microbiological quality of drinking spring water, and changes in the quality of drinking spring water, and in the environmental field, topics such as the improvement of the permitted intake of drinking spring water and the development and conservation of groundwater resources were dominated.

Study on the Hydrogeological Structure of a Karst Subterranean River and Seepage of a Karst Reservoir: A Case Study of the Yibasan Reservoir in Yunnan Province, China

Karst groundwater resources are rich, and they have important water supply significance. A karst reservoir is a means of exploiting and utilizing groundwater resources, but because of the complex hydrogeological structure and underground river pipeline in a karst area, the seepage problem of the reservoir is extremely serious. Therefore, the Yibasan Karst Reservoir (YKR) was selected as the focus of this study. The hydrogeological structure of the subterranean river system of Yutang (SRSY) was identified and the hydraulic connections between the subterranean river conduits were determined using tracer experiment and groundwater dynamic monitoring. Furthermore, the development location and depth of the karst seepage zone of the YKR were determined using geophysical exploration. The results showed that there were three subterranean river conduits in the SRSY, and there was no hydraulic connection. The northern and southern pressure and torsion faults on the sides constitute the impervious boundary of the SRSY, which provided good catchment conditions for the formation of the YKR. Additionally, the northern and main conduits of the SRSY provide a sufficient groundwater source for the YKR. Moreover, the development width of the karst seepage zone of the YKR ranges between 40 and 60 m, and the elevation ranges between 1275 and 1355 m. The research results not only provide an effective basis for the treatment of the karst seepage problem of the YKR but also provide an important reference for the development and utilization of groundwater resources in similar karst areas.

Hydrochemical characterization and water quality perspectives for groundwater management for urban development

The present study was conducted to assess groundwater quality for drinking and industrial water purposes, evaluate the driving mechanisms of groundwater chemistry, and suggest appropriate management measures to protect groundwater resources for sustainable urban development in a part of Odisha, India. Overall Water Quality Index (OWQI) and Industrial Water Quality Index (IWQI), geochemical ratios and chemometric analyses were used to identify the causes of ionic sources of natural and anthropogenic inputs. Groundwater samples were collected and analysed for chemical parameters. The OWQI indicated that 95.93% of the study region is unfit for drinking water purposes due to high concentrations of Mg2+, Na+, Cl−, SO42−, NO3−, and F− ions supported by the ANOVA test. The IWQI found corrosion and incrustation activities in 80.05% and 94.33% of the study region, respectively, which hinders urban development. The trilinear diagram illustrated that the freshwater type changes completely to mixed water type, and then to reverse ion exchange water and saline water types due to the influence of anthropogenic sources. Gibbs diagrams explaining the mechanisms responsible for groundwater chemistry that groundwater quality moves from the rock domain to the evaporation domain due to human-induced activities. Saturation indices showed that fluoride, gypsum, and halite are in a dissolved state, and calcite is in a precipitated state. Different ionic ratios clearly illustrated that groundwater quality is mainly modified by anthropogenic sources from lithological origin. Principal component analysis (PCA) classified the chemical parameters into salinity, alkalinity, and soil-controlled factors of groundwater chemistry based on their high-positive loadings. High positive scores of PCA, and Clusters 1 and 2 of the hierarchical cluster analysis clearly differentiated polluted and unpolluted affected groundwater samples. Therefore, it is suggested to take appropriate preventive measures to improve the groundwater resources. Otherwise, there will be adverse conditions for urban activities.

Hydrogeological Analysis of Cretaceous and Tertiary Aquifers in Semiarid Sokoto Basin, Northwestern Nigeria: Implications for Sustainable Groundwater Development

Groundwater development in arid and semiarid regions is accelerated by expanded irrigation farming, industrialisation, and municipal water supply. This study provides a detailed hydrogeological analysis of sedimentary aquifers of the Sokoto basin, Northwestern Nigeria, for improved water resource development and management. Hydrogeological data, including static water level (Swl), pumping water level (Pwl), pumping test (Pt), and estimated yield (Ey), were analysed. A total of three hundred (300) observations on Swl, Pt, Pwl, Ey, and Hps were derived from boreholes and analysed using Factor analysis (FA) and Regression analysis (RA). Results showed that Gwandu Formation is the most prolific aquifer. Boreholes can yield more than 24000 litres per hour (L/h). This was followed by The Kalambaina limestone aquifer, which has the potential to yield about 15000 (L/h). However, the Taloka Formation is characterised by very poor aquifers in most of the basin, though along the Jega-Dogon Daji axis, boreholes can yield more than 24000 (L/h). Likewise, boreholes tapping the Wurno Formation can produce a maximum yield of 24000 (L/h). Estimated yields from boreholes were less than 1500 (L/h) from the Gundumi aquifer, and the maximum borehole yields were 17760 (L/h) in the Illo aquifer. Statistical modelling showed that all the analysed variables are significant concerning groundwater potentials and variability of borehole yields in the study area. Therefore, future groundwater resource development in the study area should be based on a proper analysis of the geological configurations of the Sokoto basin. This study provides an outlook on the groundwater potentials of the study area and aquifers that can provide a basis for sustainable groundwater development policy. Thus, the study has shown how multivariate and regression analysis can be used to study the hydrogeological conditions of a particular basin. Therefore, it is hoped that this study's findings will inspire other researchers to take a comparable approach.

Spatial predictions of groundwater potential using automated machine learning (AutoML): a comparative study of feature selection and training sample size in Qinghai Province, China.

Predicting groundwater potential is crucial for identifying the spatial distribution of groundwater in a region. It serves as an essential guide for the development, utilization, and protection of groundwater resources. Previous studies have primarily emphasized finding the most accurate prediction model for groundwater potential while giving less attention to the selection of training features and sample sizes. This study aims to predict groundwater potential within Qinghai Province using automated machine learning technology and assess the influence of sample sizes and feature selection on prediction accuracy. Sixteen groundwater conditioning factors were categorized into categorical and numerical variables. Four feature selection modes were utilized as input in training the model. The results indicated that, except for correlations between evaporation and landforms (- 0.8) and precipitation and normalized difference vegetation index (0.8), the Pearson correlation coefficients among the remaining sixteen factors were ≤ 0.5 or ≥ - 0.5. The models XGB-ALL, RF-Entropy, ET-CRITIC, and XGB-PCA yielded accuracy scores of 0.783, 0.685, 0.745, and 0.703, and area under curve (AUC) of 0.819, 0.724, 0.779, and 0.747, respectively. If enough samples are available with the tree model, an increased number of features can improve prediction accuracy. The principal component analysis method showed difficulty in reducing the dimensionality of the input space, while the Entropy method proved efficient. The accuracy and AUC value of the prediction model improved with an increasing number of samples. Training with 8 features and 200 data points achieved an accuracy of 0.745, sufficient to evaluate regional groundwater potential. As for training with 600 samples, the model's performance accuracy rose to 0.9, enabling precise groundwater potential prediction. The outputs of this research can provide decision-makers in groundwater resource management in Qinghai Province with crucial theoretical and practical support. The lessons learned can have future applications in similar situations.

Hydrochemical Characteristics and Quality Evaluation of Groundwater in Jinta Basin, Northwest China

The ecological environment of the northwest inland basin is fragile. The groundwater environment is a crucial influencing factor for the harmonious and sustainable development of the local social economy and the ecological environment. It is significant to investigate the groundwater chemical characteristics, water quality, and the factors that influence groundwater chemistry for groundwater resources development and construction of the ecological environment. In this study, the Jinta Basin (JB), Gansu Province, was the selected study area. Three hundred and fifty groups of shallow groundwater samples in the JB were collected and analyzed, and the characteristics and controlling factors of groundwater were determined by using Piper diagram, Gibbs plot, ion ratio relationship, and factor analysis. Single index evaluation method, comprehensive evaluation method, and entropy-weighted water quality index method were used to evaluate the water quality of the groundwater. The results indicated that the shallow pore water in the JB was alkaline as a whole; the ranges of total dissolved solids (TDS) in the Beidahe River impact area (BIA), the transition area (TA) and the Heihe River impact area (HIA) were 328.4–12,400 mg·L−1, 372.70–3774.0 mg·L−1, and 366.30–75,200.0 mg·L−1, respectively; the major anions and cations of the shallow pore water were SO42−/Cl− and Mg2+/Na+, respectively. The Piper diagram illustrated that the hydrochemical type of groundwater in the JB were mainly HCO3·SO4-Mg type, SO4·HCO3-Mg type, SO4-Mg·Na type, SO4·Cl-Na·Mg type, and Cl-Na type. The overall water quality of the shallow groundwater in the JB was relatively poor, mainly falling into Class IV-V water quality. Sulfate, total hardness (TH), TDS, chloride and sodium were the main influencing factors of water quality. The chemical characteristics of groundwater in the JB were controlled by a variety of natural factors, including rock weathering, evaporative concentration, and cation exchange, among which the main controlling factors of shallow pore water were leaching, evaporative concentration and anthropogenic activities (contribution rate of 73.94%), and sulfate rock and carbonate rock dissolution (contribution rate of 14.91%).

Review: Toward sustainable management of groundwater in the deserts of Egypt

To achieve its ambitious plans to reclaim its deserts through mega projects, Egypt is heavily relying on fossil or little-recharged groundwater. This article revisits the results and methodologies of the studies conducted over the last two decades on groundwater management and uses in the Western Desert. Most previous studies aimed at simulating different groundwater abstraction scenarios by modeling local areas in aquifer systems, but with poor definitions of boundary conditions and limited historical data. Studies were constrained by the unavailability of data, access difficulties, and high collection costs in desert lands. Thus, to propose reliable sustainable groundwater resources development plans and recommendations for future protection strategies, an open-access monitoring network representing regional aquifers is needed. More investigations based on extensive field visits are essential to monitor environmental, economic, and social conditions, identify constraints, and learn lessons for reclaiming desert lands. Moreover, this review highlighted the need to frame a rational strategy for the long-term sustainable exploitation of non-renewable groundwater in the aquifer systems of Egypt and develop an appropriate exit strategy for desert communities in case of serious water resource depletion.

Potentialities and development of groundwater resources applying machine learning models in the extended section of Manbhum-Singhbhum Plateau, India

Groundwater is essential for living earth including ecosystem functioning and development of society worldwide. In recent times, demand and pressure on groundwater resources are progressively increasing over time. Thus, the assessment and management of groundwater resources particularly in semi-arid region are very much crucial. Therefore, the principal objective of the present study is to categorize the groundwater potential areas using advanced machine learning (ML) approaches. In this study, random forest (RF), support vector machine (SVM), and extreme gradient boosting (XGBoost) algorithms have been applied. The accuracy of each model has been estimated using the receiver operating characteristics (ROC) curve. About 60.63%, 65.39%, and 53.75% of areas come under moderate to very low groundwater potential. XGBoost indicates the highest predictive capacity (AUC 0.97). The innovation of this study lies in the combination of hydrological, topographical and geological datasets into machine learning platform. This research will support water resource management worldwide.

Ambiguities in implementing regulations for sustainable groundwater resources development in Vietnam with a case study of Tra Vinh province in Mekong Delta

Study regionThe study region is the coastal Tra Vinh province located in Mekong Delta, Vietnam Study focusThe study aims to clarify the ambiguities in implementing Vietnam's regulation on restrictions of groundwater abstraction in Mekong Delta. Three ambiguities were identified, namely, how should half of the saturated thickness of the unconfined aquifer be computed; is the water level depth of 30 m for the confined aquifer sufficient to prevent seawater intrusion and land subsidence; and why is the interference of water use rights of neighbouring provinces not considered. Numerical groundwater flow, saltwater transport and land subsidence were constructed for Tra Vinh province to assess water level requirements from Vietnam regulation and important constraints for groundwater sustainability. The model results show that although all scenarios satisfy groundwater level requirements from the Vietnam regulation, only the mitigation scenario combined with reducing abstraction and increasing recharge can lead to sustainable development. New hydrological insights for the regionThe current groundwater abstraction in Tra Vinh province has caused groundwater storage depletion and induced seawater intrusion, land subsidence, and captured groundwater inflow from neighbouring provinces. When the business as usual continues, seawater may intrude 4–5 km inland and cumulative land subsidence may reach 1.5 m by 2100. Reduction of current abstraction by 50% supplemented with the increase of recharge by 1.5 times in the dunes can lead to sustainable development.