Sustainable Development Of Groundwater Resources Research Articles

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.

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

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.

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.

Trends and frontiers in coal mine groundwater research: insights from bibliometric analysis

Globally, studying the impact of coal mining on groundwater remains challenging. This is because the exploitation of coal resources and the sustainable development of groundwater resources involve economic, social, and environmental aspects. Over the last few decades, the number of publications on groundwater-related studies in coal mining areas has increased. However, they are not currently reviewed in a widely visible manner through bibliometric analyses. This study investigated groundwater research in coal mining areas worldwide using scientometric analysis based on 1196 articles from the Web of Science database to provide a global perspective and gain quantitative insight into research frontiers and trends in the field by mapping existing knowledge. We analyzed the key contributors and development processes of coal mine groundwater research and identified four research frontiers based on scientometric mapping results with an understanding of the research field: numerical modeling, conceptual modeling and mechanisms, feedback mechanisms between anthropogenic-environmental systems and groundwater systems, ground subsidence management, groundwater quality evaluation and risk assessment, and groundwater resource management in coal mines. Finally, we summarize the current challenges and propose methods to promote the green mining of coal resources and the sustainable development and management of groundwater resources.

Analysis of sustainable groundwater management policies for urban development

AbstractGroundwater is essential to human well‐being and sustains a variety of aquatic ecosystems in both urban and rural settings. Yet, it is commonly overlooked in these contexts. As a result, groundwater may be very important to the development and well‐being of many nations if it is properly evaluated and utilized. Although the possibility for sustainable groundwater resource development is still debated in the literature, these issues still lack quantitative understanding. In order to assess groundwater potential in two different urbanized regions of “Northern Kerala, Southern India,” this research uses the “Enhanced Fuzzy Analytic Hierarchy Process (E‐Fuzzy AHP) based Multi‐Criteria Decision Making (MCDM)‐Geospatial Framework employing Improved Particle Swarm Optimization (IPSO)”. The study area is a coastal region that is quickly becoming urbanized and relies on groundwater resources to meet its basic needs. By incorporating both spatial and non‐spatial data into the Geographic Information System (GIS) platform, a groundwater potential zone map with an accurate integer value was created, known as the “groundwater potential index (GWPI)”. The very excellent potential zone occupies 35% and 11%, respectively, of the “urban and peri‐urban zones,” according to the final groundwater potential map, which employed the quantile technique to split the research territory into four zones. The statistical effectiveness and dependability of results in the overall decision‐making phase were examined in the validation study using the data on mean water depth level, and it was found that the reliability was well within the tolerance threshold.

Hydrogeophysical Investigation in Parts of the Eastern Dahomey Basin, Southwestern Nigeria: Implications for Sustainable Groundwater Resources Development and Management

Geoelectrical resistivity measurements were conducted in five locations within the eastern portion of the Dahomey basin for the purpose of subsurface evaluation and detecting saturated zones. The locations are Covenant University (L1), Bells University (L2), Oju-Ore-Ilogbo Road (L3), Obasanjo-Ijagba Road (L4), and Iyana Iyesi (L5). The study was carried out to avert the common challenges of drilling low-yield groundwater boreholes in the area. A total of 30 Vertical Electrical Soundings (VES) and five two-dimensional Electrical Resistivity Tomography (ERT) data sets have been acquired along the study areas. The geoelectrical resistivity results were integrated with the borehole logs to generate the spatial distribution of the subsurface lithologies in the area. The delineated subsurface lithologies include the topsoil (lateritic clay), clayey sand, sandy clay, fine silty sand, coarse sand, and shale/clay units. The fine silty sand and coarse sand units were identified as the two main aquifer units within the area. The depths to the upper aquifer unit in the area include 31.7–96.7 m, 38.5–94.0 m, 30.7–57.5 m, 39.1–63.4 m, and 46.9–57.5 m for locations L1, L2, L3, L4, and L5, respectively. At the same time, the depths to the lower aquifer unit in the area include 43.4–112.7 m, 52.2–108.0 m, 44.2–72.5 m, 53.7–78.5 m, and 63.5–72.9 m for locations L1, L2, L3, L4, and L5, respectively. The estimated hydraulic parameters for both aquifers show they are highly productive with mean porosity, mean hydraulic conductivity, and mean transmissivity of 20–22%, 12.4–17.0 × 10−2 m/s, 1.56–2.18 m2/s for the upper aquifer, and 48–50%, 371–478 × 10−2 m/s, 50.00–62.14 m2/s for the lower aquifer. By focusing on these aquifer systems during exploration, sustainable groundwater resources can be secured, providing relief to homeowners within the study area who might otherwise face the frustration of drilling unproductive and low-yield boreholes. However, it is crucial to consider the presence of sub-vertical faults in the study area, as these faults can significantly impact groundwater development and management. These sub-vertical structural faults may lead to changes in the permeability, hydraulic conductivity, and transmissivity of the delineated aquifers, affecting their productivity across the divide and ultimately influencing the overall water availability in the area. Careful consideration of these geological factors is essential for effective aquifer management and sustainable groundwater utilisation.

Dynamic variation of groundwater level and its influencing factors in typical oasis irrigated areas in Northwest China

Abstract It is essential to analyze the dynamic characteristics of regional groundwater levels and their driving factors for the rational development of groundwater in irrigated areas. This article explores the spatial distribution characteristics of the amplitude of groundwater level change in the Shihezi irrigated area by using the ArcGIS interpolation method and contrast coefficient variance method and analyzes the influence factors of dynamic change of groundwater levels by integrating the grey relational degree and path analysis methods and obtaining the sensitivity of each influencing factor to changes in groundwater levels and the relative importance of the influencing factors. The following results are obtained: (1) the groundwater level of the Shihezi irrigated area showed an overall increasing trend from 2012 to 2019, with a fluctuation range of 12.26–14.14 m. The groundwater level in the southeast of the irrigated area showed an upward trend, while the groundwater level in the northwest area showed a downward trend. (2) The groundwater level in the irrigated area first increased, then decreased, and then increased again. The variance of the contrast coefficient in the irrigated area ranged from 0.04 to 11.31, and the fluctuation range of the groundwater level in the central area was higher than that in the northern and southern areas. (3) The irrigated area of cultivated land and evaporation are the main factors affecting groundwater level change in the Shihezi irrigated area. The grey relation analysis shows that the irrigated area of cultivated land has the highest grey correlation degree with the evolution of the groundwater level, which is 0.947, and the average grey correlation index is between 0.74 and 0.95. Path analysis showed that the irrigated area of cultivated land, surface water usage, and evaporation were the main factors affecting groundwater levels. Human activities are one of the main driving forces of groundwater level change, and the research results provide a theoretical basis for the rational utilization and sustainable development of groundwater resources in the Shihezi irrigation area.

Significance of geomorphic indicators for identification of groundwater recharge potential in the Khapri watershed of Deccan Volcanic Province (DVP), district Dangs, western India

The district Dangs of western India, marks the extension of Western Ghats in Gujarat state. It is characterized by less transmissible basaltic lithology of Deccan Volcanic Province (DVP), rugged trappean highlands and moderate to very steeply sloping surfaces. Despite receiving high average annual rainfall (2000 mm) the terrain framework produces high runoff than infiltration (recharge), leading to groundwater crisis. In such terrains, where lithology is homogenous, the natural groundwater recharge is significantly influenced by geomorphic indicators (landforms, drainage characteristics and slope). Therefore, identification of groundwater recharge potential (here after referred as GWRPOT) is crucial for the sustainable development of groundwater resource. In the present study GWRPOT is identified on the basis of geomorphic indicators (Gi) in sub-watersheds of Khapri, district Dangs of DVP. To generate the database on geomorphic indicators the IRS-LISS-III (24 m) satellite data, Survey of India topographic maps (1:50,000), and SRTM-DEM are used. The ranks are assigned to geomorphic indicators of each sub-watershed by considering their aerial coverage, influence on GWRPOT and field studies. The summation of average ranks of each geomorphic indicator viz., landform (Gc), drainage characteristics (Dc) and slope (Sc) is used to compute Gi value. On the basis of Gi, the GWRPOT is identified and categorized as very poor (SW-5), poor (SW-3, SW-2, SW-10), moderate (SW-7, SW-4), good (SW-11), very good (SW-1, SW-8, SW-9) and excellent (SW-6). These results are validated with seasonal groundwater level fluctuations in 33 dug-wells, which shows positive correlation between Gi and groundwater fluctuation (R2 = 0.77). Further, the sub-watershed prioritization is carried out to highlight the need of improving the GWRPOT and thereby sustainability.

Study on the Carrying Capacity and Change Trend of Groundwater Resources in Coal Mining Area: A Case Study of a Coal Mine in Northwest China

The groundwater resources carrying capacity is a comprehensive metric that assesses the ability of groundwater resources in a region to support industrial production and socioeconomic development. In arid regions, the calculation and analysis of the carrying capacity of groundwater resources are of paramount importance for guiding sustainable mining practices in coal mines. This study utilized a combination of the Fuzzy Comprehensive Evaluation (FCE) method and the Analytic Hierarchy Process (AHP) method to analyze the carrying capacity of groundwater resources in the coal mine located in northwest China. The results showed that the groundwater resources carrying capacity in the study coal mine was at a low level from 2011 to 2020 and the development and utilization of groundwater will reach its limit. The change trend of the carrying capacity showed a slight increase following a decline, with the highest value 0.5021 and the lowest 0.3518. The factors that significantly impacted the size of the carrying capacity included the total groundwater resources, the degree of groundwater development and utilization, and the per unit GDP of water consumption. To ensure sustainable development, the optimization of coal mining technology and the improvement of groundwater utilization efficiency should be promoted, while the rate of groundwater development should be slowed. The findings of this study offer valuable insights for guiding the sustainable development of groundwater resources in the coal mine of arid areas in the future and have practical implications.

Groundwater recharge estimation using in-situ and GRACE observations in the eastern region of the United Arab Emirates

The intensive agricultural expansion and rapid urban development in Abu Dhabi Emirate, United Arab Emirates (UAE) have resulted in a major decline in local and regional groundwater levels. By using the latest release (RL06) of Gravity Recovery and Climate Experiment (GRACE) satellite measurements and Global Land Data Assimilation System (GLDAS) products, the groundwater storage change was computed and compared with the time series of in-situ monitoring wells over the period of 2010–2016. The RL06 GRACE products from Jet Propulsion Laboratory (JPL), University of Texas Center for Space Research (CSR), German Research Center for Geosciences (GFZ), and JPL mass concentrations (MASCON) were assessed and have shown satisfactory agreements with the monitoring wells. The JPL MASCON reflected the in-situ groundwater storage change better than the other GRACE products (R = 0.5, lag =1 month, RMSE = 13 mm). The groundwater recharge is estimated for the study area and compared with the in-situ recharge method that considers multi recharge components from the rainfall, irrigation return flow and internal fluxes. The results show that the agreements between in-situ and GRACE-derived recharge estimates are highly agreeable (e.g., R2 = 0.91, RMSE = 1.5 Mm3 to 7.8 Mm3, and Nash-Sutcliff Efficiency = 0.7). Using the Mann-Kendall trend test and Sen's slope, the analyses of policies, number of wells, and farm areal expansion with groundwater time series derived from GRACE helped to validate GRACE and emphasize the importance of regulations for sustainable development of groundwater resources. The impacts of subsidy cuts after 2010 can be captured from the GRACE data in the eastern region of Abu Dhabi Emirate. The linear trend of groundwater storage anomaly obtained from GRACE over the period from 2003 to 2010 is −6.36 ± 0.6 mm/year while it showed a decline trend of −1.2 ± 0.6 mm/year after the subsidy cut. The proposed approach has a potential application for estimating groundwater recharge in other arid regions where in-situ monitoring wells are limited or absent.

GLOBAL OPTIMIZATION VERY FAST SIMULATED ANNEALING INVERSION FOR THE INTERPRETATION OF GROUNDWATER POTENTIAL

This study examines the inversion modelling of one-dimensional Schlumberger configuration resistivity data using the Very Fast Simulated Annealing (VFSA). Detailed identification and mapping of aquifer conditions is very important for the sustainable development of groundwater resources in an area. Vertical electrical sounding (VES) and surface electrical resistivity surveys have proven very useful for studying groundwater due to their simplicity and cost effectiveness. Global optimization inversion method also provides an inversion solution that is not expected to be trapped in a local minimum solution, so that it will get results that are closer to the actual situation. The VFSA method is inspired by phenomena in metallurgy related to the formation of crystals in materials caused by thermodynamic processes. This inversion scheme was tested initially with free noise synthetic data and with noise 5%. Furthermore, the program is applied to field data that has been measured in Ambon City, Maluku, Indonesia. The results of the VFSA inversion on field data obtained four layers consisting of top soil (141.2 ± 0,61 m) with a thickness of 1.43 m, andesite breccia rock (355.90 ± 0.46 m) with a thickness of 4 m, lapilli tuff (93.40 ± 0.31 m) with 30 m thick, then the last is the coarse tuff layer (34.30 ± 0.15 m) which is estimated as an aquifer.

Response of hydrogeological processes in a regional groundwater system to environmental changes: A modeling study of Yinchuan Basin, China

The sustainable development of groundwater resources in arid and semi-arid regions is a challenging task hindered by climate change and human activities. The rational utilization and management of groundwater resources is, therefore, dependent on an understanding of the influences of human and climatic factors on the spatial distribution of groundwater resources and their change over time. The thick Quaternary aquifers in the Yinchuan Basin, China were used herein as an example of how to quantitatively assess spatial and temporal trends in groundwater resources in response to human activities and climate change. A 3D transient groundwater flow model was constructed and used to simulate the evolution and spatial variability of hydrogeological processes from 1990 to 2020. By subsequently applying regime shift detection and correlation analysis to the simulation results, we found that: 1) groundwater storage was continuously depleted over the 30-year period, reaching a cumulative depletion of 1.89×109 m3; 2) human activities were mainly responsible for variations in regional hydrogeological processes for a period of up to 30 years. Climate only affected short-term interannual fluctuations in groundwater storage; 3) human activities (e.g., river water diversion and groundwater abstractions) were the decisive factors causing a continuous reduction of groundwater resources. A policy-driven reduction in water diversion from the Yellow River directly led to a significant drop in groundwater storage, which had a consequent effect on surface water and groundwater interactions and altered agricultural irrigation patterns (crop patterns and irrigation methods); 4) the amount of groundwater recharge from the Yellow River and local lakes increased from 1990 to 2020, whereas the discharge of groundwater to the Yellow River and lakes decreased.

Application of data-mining technique and hydro-chemical data for evaluating vulnerability of groundwater in Indo-Gangetic Plain.

Vulnerability of groundwater is critical for the sustainable development of groundwater resources, especially in freshwater-limited coastal Indo-Gangetic plains. Here, we intend to develop an integrated novel approach for delineating groundwater vulnerability using hydro-chemical analysis and data-mining methods, i.e., Decision Tree (DT) and K-Nearest Neighbor (KNN) via k-fold cross-validation (CV) technique. A total of 110 of groundwater samples were obtained during the dry and wet seasons to generate an inventory map. Four K-fold CV approach was used to delineate the vulnerable region from sixteen vulnerability causal factors. The statistical error metrics i.e., receiver operating characteristic-area under the curve (AUC-ROC) and other advanced metrices were adopted to validate model outcomes. The results demonstrated the excellent ability of the proposed models to recognize the vulnerability of groundwater zones in the Indo-Gangetic plain. The DT model revealed higher performance (AUC=0.97) followed by KNN model (AUC=0.95). The north-central and north-eastern parts are more vulnerable due to high salinity, Nitrate (NO3-), Fluoride (F-) and Arsenic (As) concentrations. Policy-makers and groundwater managers can utilize the proposed integrated novel approach and the outcome of groundwater vulnerability maps to attain sustainable groundwater development and safeguard human-induced activities at the regional level.

Alleviating drought and water scarcity in the Mediterranean region through managed aquifer recharge

Drought and water scarcity can significantly impair the sustainable development of groundwater resources, a scenario commonly found in aquifers in the Mediterranean region. Water management measures to address these drivers of groundwater depletion are highly relevant, especially considering the increasing severity of droughts under climate change. This study evaluates the potential of managed aquifer recharge (MAR) to offset the adverse effects of drought and water scarcity on groundwater storage. Los Arenales aquifer (central Spain), which was unsustainably exploited for irrigation in the second half of the twentieth century, is employed as a case study. Two neighbouring zones within this aquifer are contrasted, namely, Los Arenales (LA) and Medina del Campo (MC). The primary difference between them in terms of water resources management is the wide-scale implementation of MAR systems in LA since the early 2000s. Several groundwater statistical methods are used. Groundwater-level trend analysis and average piezometric levels show in LA a faster recovery of aquifer storage and less susceptibility to drought compared to MC. On the other hand, standardised precipitation indexes and standardised groundwater level indexes of detrended groundwater-level time series, which do not include the effects of MAR, show that LA can be more negatively affected by drought and groundwater abstraction. The sharper recovery of piezometric levels in LA when considering MAR, and bigger drought impacts observed when the effects of this measure are removed, demonstrate that MAR can effectively alleviate the impacts of water scarcity and drought, providing an adaptation solution to climate change worldwide.

Stakeholders’ Perspective on Groundwater Management in Four Water-Stressed Mediterranean Areas: Priorities and Challenges

Recent studies highlight the fragility of the Mediterranean basin against climate stresses and the difficulties of managing the sustainable development of groundwater resources. In this work, the main issues related to groundwater management have been identified from the stakeholder’s perspective in the following four representative water-stressed Mediterranean areas: the coastal aquifer of Comacchio (Italy), the Alto Guadalentín aquifer (Spain), the alluvial aquifer of the Gediz River basin (Turkey), and the Azraq aquifer (Azraq Wetland Reserve, Jordan). This has been achieved by designing a methodology to involve and engage a representative set of stakeholders, including a questionnaire to learn their point of view concerning the current management of aquifer systems and their experience with the already available tools for groundwater resource management, such as monitoring networks and numerical models. The outcome of the survey has allowed us to identify both particular and common challenges among the four study sites and among the various groups of stakeholders. This information provides valuable insights to improve the transfer of scientific knowledge from the research centers to the authorities managing the groundwater resources and it will help to plan more effective research activities on aquifer management. The proposed methodology could be applied in other aquifers facing similar problems.

Hydrogeochemical insights into the signatures, genesis and sustainable perspective of nitrate enriched groundwater in the piedmont of Hutuo watershed, China

Groundwater nitrate contamination has been a global issue threatening water supply, especially in arid and semiarid piedmonts. An extensive hydrogeochemical investigation was performed in an intensively human-impacted semiarid piedmont in North China. Groundwater is nearly neutral to alkaline in nature with large variations of salinity. The concentration of nitrate in groundwater ranges from 4.89 mg/L to 402.40 mg/L with 64.29% of values beyond the permissible limit of 50 mg/L recommended by World Health Organization. Hydrogeochemistry changes gradually from fresh HCO3-Ca type waters to moderately saline Cl-Ca type with the increase of nitrate content in groundwater. Anthropogenic inputs from residential land usage are responsible for the nitrate enrichment and salinity increase. The Entropy-weighted water quality index value ranges from 29 to 327 with a mean of 82, and 21.43% of sampled groundwaters under the categories from medium to extremely poor quality for drinking purpose. Non-carcinogenic risks posed by nitrate, nitrite and ammonia via dermal and oral pathways were assessed for infants, children, adult females and males. The overall non-carcinogenic risk of investigated groundwaters ranges from 2.91 × 10−1 to 2.38 × 101 (mean of 4.00 × 100) for infants, 1.29 × 10−1 to 1.06 × 101 (mean of 1.78 × 100) for children, 5.74 × 10−2 to 4.70 × 100 (mean of 7.90 × 10−1) for adult females, and 4.24 × 10−2 to 3.47 × 100 (mean of 5.83 × 100) for adult males. Health risks vary but all population groups are at risk. These health threats are mainly posed by nitrate through the oral ingestion pathway, with minors being more susceptible. Therefore, measures including awareness improvement of local residents, environmental protection, differential water supplies based on water quality, and targeted water treatment are recommended to achieve sustainable groundwater resource development in arid and semiarid piedmonts.

Spatiotemporal variation and periodic evolution characteristics of groundwater in the Xining area of China, eastern Qinghai–Tibet Plateau

As an important water source, groundwater profoundly influences global human survival and production. The spatiotemporal characteristics of groundwater and the periodic variation law of different time scales must be analyzed to understand the dynamic situation of this resource and to provide scientific guidance for its rational utilization and management. In this study, the temporal and spatial variability and periodicity of groundwater level in the Xining region of eastern Qinghai–Tibet Plateau in China were studied using the traditional statistical method, geographic information system, and Morlet wavelet analysis. Results show that the groundwater dynamics in the study area are mainly controlled by three factors, namely, the amount of river water infiltration, discharge from groundwater, and artificial exploitation. These factors can be divided into three dynamic types, namely, hydrological, hydrological exploitation, and runoff discharge, according to their combination relationship. From 1980 to 2020, the groundwater depth in Xining initially increased before stabilizing and eventually decreasing. As revealed in the spatial variability analysis, groundwater depth demonstrates a huge spatial difference with a moderate spatial variation intensity across different periods. Moreover, the spatial correlation of groundwater in the abundant season is lower than that in the dry season mainly due to increasing artificial exploitation. Meanwhile, the Kriging interpolation of the spherical model in the geographic information system reveals that the groundwater in Xining is deep in the south and east and shallow in the north and west. From the 1960s to 2000s, the inter-annual groundwater in the region continuously declined due to chronic overexploitation, with a maximum cumulative depth of 15 m. Afterward, the amount groundwater extraction was further reduced, and the amount of rainfall significantly increased in recent years. Accordingly, the cone of depression underwent an evolutionary process involving periods of expansion, stability, and shrinkage. The annual groundwater level in most monitoring wells within the study area demonstrated the same multi-year scale time-variation characteristics with an evident regular periodic variation on the 9-14a and 17-25a time scales according to the results of the Morlet wavelet transform analysis. The temporal sequence of groundwater from 1980 to 2020 had two main periods, namely, 12a and 21a. According to these time scales, the groundwater level in Xining will continue to increase in the short term, which provides a scientific theoretical basis for the long-term sustainable development of groundwater resources and government decision-making.

Integrated approach for the evaluation of groundwater quality through hydro geochemistry and human health risk from Shivganga river basin, Pune, Maharashtra, India.

The present study is focused on seasonal variation in groundwater quality, hydrochemistry, and associated human health risk in the Shivganga river basin, Western Maharashtra, India, to promote sustainable development of groundwater resources of this semi-arid region. The qualitative geochemical analysis, contamination levels, and human health risk assessment (HHRA) of groundwater are integral steps in groundwater management in the Deccan Plateau basalt flow region of India. Representative groundwater samples (n = 68) collected from the Shivganga River basin area of Pune district, Maharashtra, during pre-monsoon (PRM) and post-monsoon (POM) seasons in 2015 were analyzed for major cations and anions. According to the World Health Organization (WHO, 2017) drinking standards, EC, total dissolved solids, hardness, bicarbonate, calcium, and magnesium surpassed the desirable limit. Boron and fluoride content exceeded the prescribed desirable limit of the WHO. The pollution and drinking suitability were assessed by computing pollution index of groundwater (PIG), groundwater quality index (GWQI), and HHRA particularly for boron and fluoride toxicity. PIG values inferred that about 6% of groundwater samples has moderate, 24% has low, and 70% has insignificant pollution in the PRM season, while only 1 sample (3%) showed high pollution, 6% showed low, and 91% showed insignificant pollution in the POM season. GWQI classification demonstrated that 27% and 15% samples are within the poor category, and only 15% and 18% of the samples fall into excellent water category in the PRM and the POM seasons, respectively. Total hazard index (THI) revealed that 88% of children, 59% of adults, and about 38% of infants are exposed to non-carcinogenic risk, as THI values (>1) were noted for the PRM season, while 62% of children, 47% of adults, and 24% of infants are vulnerable to non-carcinogenic health hazard during the POM period.

Hydrochemical characteristics and quality assessment of groundwater aquifers northwest of Assiut district, Egypt

Groundwater quality assessment is essential for the sustainable development of groundwater resources and for determining their use for domestic, irrigation, or industrial purposes. The objective of this study is to determine the hydrochemical characteristics and water quality of the groundwater aquifers in the area to the northwest of Assiut district, Egypt, and to map their spatial variations in terms of suitability for domestic and irrigation purposes. Two main aquifers are presented in the study area, the Pleistocene and the Eocene aquifers. Water samples were collected from 58 wells across the study area and analyzed to determine their physicochemical properties and calculate the water quality indices. The hydrochemical investigation shows that the domination of the major ions in the Pleistocene aquifer is in the following order: Na+ > Ca2+ > Mg2+ > K+ and Cl− > HCO−3 >SO−4 but it takes the trend of Na+ > Mg2+ > Ca2+ > K+ and Cl− > HCO−3 >SO−4 in the Eocene aquifer. Most of the Pleistocene aquifer samples are suitable for drinking while about a half of the Eocene samples are unsuitable for drinking due to their high salinity that ranges from 235 to 2830 for the former and from 350 to 4150 for the latter. The Eocene water samples and most of the Pleistocene water samples are unsuitable for domestic use due to the high level of hardness that ranges from 67.88 to 1923 for the former and from 26.56 to 944.6 for the latter. Groundwater suitability for irrigation was assessed based on sodium adsorption ratio (SAR), residual sodium carbonate (RSC), Kelley ratio (KR), the magnesium hazard (MH), and potential salinity (PS). Most of the Pleistocene and a half of the Eocene samples are suitable for irrigation. Maps showing the spatial variations of different groundwater quality parameters were produced using ArcGIS.