Groundwater Management Strategies Research Articles

Continuity Analysis of Groundwater Aquifers Using Geoelectrical Vertical Electrical Sounding (VES) Method with Schlumberger Configuration in Serayu-Citanduy Road and Golf Course, Tanah Merah Village, North Samarinda District, Indonesia

This study aims to analyze the continuity of the aquifer system between the Serayu-Citanduy area and the Golf Course area in Tanah Merah Village, North Samarinda District, using the Vertical Electrical Sounding (VES) method with Schlumberger configuration. Building on previous research that compared geoelectrical mapping and sounding methods for identifying aquifer layers in the Serayu-Citanduy area, this study focuses on aquifer connectivity based on resistivity profiles and geological interpretation. The VES data collected from eight measurement points revealed significant variations in lithology and aquifer types. At the Golf Course, the surface layer consists of soil (0.8 to 2.6 m depth), overlying a thick silt layer (up to 160 m depth) and a permeable sandstone aquifer between depths of 152.7 m and 160 m. The resistivity of the sandstone aquifer is approximately 20-50 Ωm. Meanwhile, at the Serayu-Citanduy Road, the lithology is divided into five main layers, with the surface layer (0.8 to 2.5 m) followed by a silt layer (5.2 to 22.9 m) and a sandstone layer from 22.9 m to 200 m depth. The resistivity of the sandstone aquifer here is higher, ranging from 50 to 150 Ωm, and is identified as an unconfined aquifer above a shale layer. Below 100.1 m, a confined aquifer is found beneath the shale layer, with resistivity values exceeding 100 Ωm. The correlation between the VES points at the Golf Course and Serayu-Citanduy Road shows continuity between the aquifer systems despite variations in thickness. These findings provide new insights into the hydrogeology of Tanah Merah and highlight the importance of groundwater management strategies for sustainable water use in North Samarinda District.

Hydrogeological Assessment and Steady-State Groundwater Flow Modeling for Groundwater Management in the Golina River Sub-Basin, Northern Ethiopia, Using MODFLOW 6

Unsustainable groundwater extraction for domestic and agricultural purposes, particularly crop irrigation, is leading to dramatic reductions in the quantity and quality of groundwater in many developing countries, including Ethiopia. Assessing and predicting groundwater responses to hydraulic stress caused by overexploitation related to anthropogenic activities and climate change are crucial for informing water management decisions. The aim of this study is to develop a three-dimensional steady-state groundwater flow model for the Golina River Sub-Basin to understand the relationship between groundwater recharge and groundwater pumping and their impacts under steady-state conditions from the perspective of groundwater management. The model was created using MODFLOW 6 and discretized into 345 rows and 444 columns with a grid resolution of 100 m by 100 m. The subsurface was modeled as two layers: a clastic alluvial layer overlying a weathered and fractured bedrock. The surface-water divide of the Golina River Sub-Basin was treated as a no-flow boundary. The initial values of horizontal hydraulic conductivity ranged from 0.001 m/day for rhyolite to 27.26 m/day for alluvial deposits. The aquifer recharge rates from the WetSpass model ranged from 1.08 × 10−3 to 2.25 × 10−4 m/day, and the discharge rates from the springs, hand-dug wells, and boreholes were 2.79 × 104 m3/day, known flux boundaries. Sensitivity analysis revealed that the model is very sensitive to hydraulic conductivity, moderately sensitive to aquifer recharge, and less sensitive to groundwater pumping. Calibration was performed to match observed and simulated hydraulic heads of selected wells and achieved a correlation coefficient of 0.998. The calibrated hydraulic conductivity ranged from 1.2 × 10−4 m/day for rhyolite to 20 m/day for gravel-dominated alluvial deposits. The groundwater flow direction is toward the southeast, and the water balance indicates a negligible difference between the total recharge (207,775.8297 m3/day, which is the water entering the aquifer system) and the total pumped volume (207,775.9373 m3/day, which is the water leaving the aquifer system). The scenario analysis showed that an increase in the pumping rate of 25%, 50%, and 75% would result in a decrease in the hydraulic head by 4.64 m, 10.18 m, and 17.38 m, respectively. A decrease in recharge of 25%, 50%, and 75% would instead result in hydraulic-head declines of 6 m, 15.29 m, and 46.97 m, respectively. Consequently, the findings of this study suggest that decision-makers should prioritize enhancing integrated groundwater management strategies to improve recharge rates within the aquifer system of the study area.

Integrating geospatial, hydrogeological, and geophysical data to identify groundwater recharge potential zones in the Sulaymaniyah basin, NE of Iraq

Groundwater is a critical resource for sustaining human activities, particularly in urban areas, where its importance is exaggerated by growing water demands, urban expansion, and industrial activities. Ensuring future water security necessitates an in-depth understanding of groundwater recharge dynamics, which are often complex and influenced by rapid urbanization. The alarming decline in groundwater resources in both urban and rural regions underscore the urgency for advanced groundwater management strategies. However, identifying and evaluating groundwater recharge potential zones (GWPZs) remains a challenge due to the dynamic interplay of hydrogeological and urban development factors. This study employs an integrated approach combining geographic information system (GIS), remote sensing, and multi-criteria decision analysis using the analytical hierarchy process (MCDA-AHP) to delineate GWPZs in the Sulaymaniyah Basin (SB). The methodology is further supported by hydrogeological data and validated through geophysical investigation using electrical resistivity tomography (ERT) data. For the MCDA-AHP, six thematic layers including rainfall, geology, lineament density, slope, drainage density, and land use/land cover were derived from satellite imagery, geological surveys, and well data. These layers were ranked based on their relative influence on groundwater recharge and integrated using GIS-based weighted overlay analysis to generate groundwater potential maps. The results identified three potential zones for groundwater recharge: low (11.26%), moderate (45.51%), and high (43.23%). Validation using ERT data and receiver operating characteristics (ROC) analysis revealed strong agreement, with an area under the curve (AUC) accuracy of 86%. These findings demonstrate the robustness of the integrated approach, providing a reliable tool for minimizing hydrogeophysical exploration costs and reducing the number of unsuccessful boreholes.

Implications of seasonal variations of hydrogeochemical analysis using GIS, WQI, and statistical analysis method for the semi-arid region

Groundwater quality assessment is crucial for sustainable water resource management in Maharashtra, India, where groundwater helps for main water sources for irrigation, domestic, and industrial sectors. Despite numerous studies on regional groundwater quality, there remains a lack of integrated research combining hydrogeochemical analyses with advanced spatial and statistical techniques. This study addresses this gap by developing a comprehensive groundwater quality assessment framework that uniquely integrates hydrogeochemical analyses, geographic information system (GIS) techniques, water quality index (WQI), and multivariate statistical approaches in the Morna River Basin. A total of 82 water samples were analyzed for physicochemical parameters in the pre-monsoon (PRMS) and post-monsoon (POMS) seasons. The WQI analysis revealed that 46.15% of samples exhibited excellent water quality, while 48.72% showed good quality during both seasons, though a notable quality decrease was observed during the POMS. Correlation analysis identified significant positive associations (p < 0.05) between key parameters, including Mg-TH, EC-pH, and Ca2+-TH. Principal component analysis identified six components explaining 75.534% of total variance in PRMS, with the first component contributing 17.437%. In POMS, five components explained 70.963% of variance, with the first component contributing 20.653%. Factor analysis revealed that mineral dissolution, agricultural activities, and anthropogenic inputs were the primary factors influencing the water chemistry. The spatial distribution maps generated through GIS analysis identified hotspots of contamination. This integrated approach provided a robust framework for understanding the complex interactions between natural and anthropogenic factors impact on the groundwater quality. The results suggest regural monitoring of water quality and an identified hotspots and implementation of rules and regulations on the agricultural practices and waste disposal. This research contributes to support of groundwater management strategies and provides a methodological framework appropriate to similar hydrogeological settings in other area or worldwide.

Multidecadal drought impacts on the Lower Colorado Basin with implications for future management

Overallocation of Colorado River water and groundwater alongside multidecadal drought underscore the need to understand water-resource dynamics. Here we assess water-storage variations using satellites, regional modeling, and monitoring to inform future management. Total water storage loss from Gravity Recovery and Climate Experiment (GRACE) satellites was dominated by Lower Basin declines (80% of total), exceeding Lake Mead capacity by 40%. These Lower Basin storage declines were dominated by groundwater depletion (60% of total), with cumulative depletion hotspots ≤11 m (2002–2023) and subsidence ≤1 m (2010–2024). Regional groundwater modeling shows intensive depletion (1940s–1970s) followed by partial recovery since the early 1980s from irrigation reduction, wet climate cycles (early 1980s–1990s), and Colorado River water transfers to Central Arizona. Managed aquifer recharge and incidental recharge from imported surface-water irrigation led to a 3-m average groundwater-level rise in Central Arizona Active Management Areas (2000–2023). Projected declines in Colorado River water transfers to Central Arizona could lead to further depletion and subsidence. Water transfers from agricultural to municipal/industrial sectors would improve future management. Understanding system dynamics related to climate and human drivers is essential for developing future conjunctive surface-water and groundwater management strategies.

Hydrochemical evaluation of the strip aquifer in Srivaikundam region, Southern India: implications for drinking and irrigation

The present study focuses on understanding the groundwater geochemistry and hydrochemical characteristics of the Srivaikundam region, Tamil Nadu, with special concern on seasonal and spatial variations in groundwater quality. Groundwater samples were collected during the pre-monsoon (2021) and post-monsoon (2022) seasons, and required water quality parameters were analyzed, including pH, total dissolved solids (TDS), electrical conductivity, and concentrations of major ions such as sodium (Na⁺), calcium (Ca2⁺), magnesium (Mg2⁺), chloride (Cl⁻), bicarbonate (HCO₃⁻), and sulfate (SO₄2⁻). Further ionic ratios, such as Na + /Cl⁻ and Ca2⁺/Mg2⁺, helped to characterize the groundwater quality to understand the ion exchange occurring in areas affected by seawater intrusion. The Gibbs diagram revealed that groundwater chemistry is primarily controlled by rock-water interactions, while the ionic ratios confirmed the significant influence of marine water mixing in the coastal aquifers. In addition to that, the study highlights the role of the strip aquifer system in regulating groundwater flow and storage, which influences the seasonal variations in water quality. The strip aquifer system, consisting of both unconfined and semi-confined aquifers, is highly vulnerable based on the impacts of anthropogenic activities and reflected in the elevated concentrations of salts and other ions. According to the WHO 2017 guidelines, certain areas exhibited high levels of TDS, chloride, and magnesium, which alarm potential risks related to salinity and pollution, particularly due to the effects of human activities in the study region. This study exhibits the need for continuous monitoring and the adoption of effective groundwater management strategies in the study region to mitigate the impacts of seawater intrusion and pollution on the water quality of the study region.

Hydrogeochemical processes regulating groundwater quality and its suitability for drinking purposes in the recent alluvial plain, Blue Nile Region, Sudan.

Groundwater is becoming a critical freshwater source in the Blue Nile Region, Sudan. However, overexploitation and contamination increasingly threaten its sustainability. This study evaluates the hydrogeochemical processes influencing groundwater and its suitability for drinking purposes in the recent alluvial plain. A total of 342 groundwater samples were collected from domestic wells and monitoring boreholes in 2022 for hydrochemical and multivariate statistical analysis. The results revealed that the groundwater is predominantly of HCO3-Ca·Mg and HCO3-Ca·Na facies, reflecting the influences of natural processes like mineral dissolution and ion exchange. The key factors affecting groundwater quality include rock-water interactions and anthropogenic influences. Most groundwater samples complied with the World Health Organization (WHO, WHO. (2022). Fourth edition incorporating the first and second addenda Guidelines for drinking-water quality) and Sudanese drinking water standards. However, F- concentrations exceeding permissible levels were detected in northeastern and southwestern boreholes, posing potential health risks. Elevated total dissolved solids (TDS) were linked to mineral dissolution and agricultural runoff. The Water Quality Index (WQI) categorized 39.42% of samples as excellent, 50.72% as good, and 9.57% as poor to very poor, with 0.29% unsuitable for drinking. Areas with low human activities exhibited better water quality, while compromised samples correlated with nitrate contamination, salinity, and poor waste management practices. This study provides a robust foundation for developing sustainable groundwater management strategies to mitigate contamination risks and secure safe drinking water access.

Long-term Groundwater Quality Assessment and Management Strategies in Rapidly Urbanizing Regions: A Case Study of Tiruvallur

Long-term Groundwater Quality Assessment and Management Strategies in Rapidly Urbanizing Regions: A Case Study of Tiruvallur

Groundwater Tracer Tests as a Supporting Method for Interpreting the Complex Hydrogeological Environment of the Urbas Landslide in NW Slovenia

This study investigates groundwater flow patterns in a landslide area above the settlement of Koroška Bela in NW Slovenia using a series of tracer tests with sodium chloride (NaCl) and fluorescein (uranine). The tracer experiments, using a combination of pumping tests and continuous groundwater observations, reveal two distinct groundwater flow horizons within the landslide body: a prevailing shallower flow within highly permeable gravel layers and a slower deep flow in the weathered low-permeability clastic layers. Uranine injections suggest longer retentions, indicating complex hydrogeological conditions. Groundwater is recharged by the infiltration of precipitation and subsurface inflow from the upper-lying carbonate rocks. In the upper landslide, highly permeable gravel layers accelerate flow, especially during heavy rainfall, while downstream interactions between permeable gravel and less permeable clastic materials create local aquifers and springs. These groundwater dynamics significantly influence landslide stability, as rapid infiltration during intense precipitation events can lead to transient increases in pore water pressure, reducing shear strength and potentially triggering slope movement. Meanwhile, slow deep flows contribute to prolonged saturation of critical failure surfaces, which may weaken the landslide structure over time. The study emphasizes the region’s geological heterogeneity and landslide stability, providing valuable insights into the groundwater dynamics of this challenging environment. By integrating hydrogeological assessments with engineering measures, the study provides supportive information for mitigating landslide risks and improving groundwater management strategies.

Assessment of groundwater quality and soil properties in recharge and discharge areas of a basement environment.

This study examined the interaction between soil and groundwater in a recharge and discharge areas of Akungba-Akoko, Southwestern Nigeria. Ten water samples (R1-R5 from therecharge and D6-D10 from thedischarge areas) and ten soil samples from trial pits were collected and analyzed for hydrochemical parameters (Ca2+, Mg2+, K+, Na+, Cl+, SO42+, NO3-, PO43-, Fe, Zn, and Pb) and geotechnical investigation. Ten Schlumberger vertical electrical sounding (VES) werecarried outto determine the subsurface resistivity distribution. The concentrations of all the hydrochemical parameters including Ca2+ (0.06-0115mg/L), Mg2+ (0.05-0.099mg/L), K+ (0.021-0.042mg/L), Cl- (3.778-9.885mg/L), Zn (0.01-0.025mg/L), and Pb (0.003-0.004mg/L) were within the WHO stipulated standards. Geotechnical tests revealed that the soil was sandy-clay loam with a subgrade rating of A-2-6 or A-2-7 and medium compressibility, indicating the soil was suitable for agricultural purposes. Grain size analysis showed that the sand content of the soil (average = 48.2%) is ideal for agriculture. The VES model revealed four lithologic layers with four curve types (HA, AA, AK, and HK). The wells were located in clayey to sandy-rich weathered layer (66.9-794.4 Ωm) with an average thickness of 11.4m. The thin layer was responsible for the observed variations in groundwater during the dry season. Two viable fracture zones were identified with good potential. The health risk assessment, drinking water, and irrigation indices (WQI, SAR, SSP, KR, and MH) indicated that the groundwater in both areas was good for drinking and irrigation purposes, with no associated health risks. Nine pairwise parameters were identified with a strong correlation between changes in groundwater quality (sodium content) and the resistivity response of the soil. Continued monitoring of groundwater quality and soil resistivity response will provide effective groundwater management strategies.

Improving Groundwater Quality Through Biosphere Reserve Management: Insights from the Anaga Reserve, Tenerife

The Canary Islands, an outermost Spanish territory in the Atlantic Ocean, are renowned for their subtropical climate and significant tourism. However, substantial areas are designated for environmental protection, notably the Anaga Rural Park in Tenerife, a UNESCO Biosphere Reserve, which is the focus of this study. This research investigates the influence of Biosphere Reserve designation on groundwater quality, a crucial resource for Tenerife’s population. We analysed the physicochemical properties of groundwater within the Anaga region over a decade (2007–2016). Our findings demonstrate that groundwater quality consistently meets regulatory standards, exhibiting no evidence of pollution. This high quality is attributed to several factors, including the low population density, limited tourism impact within the reserve, and crucially, the effective soil protection measures implemented within the Biosphere Reserve. The compact geology of the region further limits infiltration and potential pollution. The sustained high quality of groundwater, even in the absence of detectable pollution, highlights the importance of ongoing monitoring to maintain this valuable resource and support local biodiversity. This case study provides a valuable model for sustainable groundwater management and soil protection strategies in other areas of Tenerife and beyond.

Analysis of Slope Stability in Construction

This paper aims to systematically analyze multiple critical factors influencing slope stability, particularly the interrelationship among pore pressure, evolution of material properties, and the factor of safety (FOS). By establishing a finite element model, an in-depth investigation into slope sliding behavior was conducted, leading to the following conclusions: (1) When the factor of safety (FOS) reaches 1.9, the slope exhibits non-convergence, indicating the onset of instability, which highlights the necessity of particular attention to stability during the design process under critical conditions; (2) The non-uniform distribution of pore pressure and the presence of unsaturated soil layers significantly impact slope stability. This is particularly critical in the toe region, where sliding phenomena are notably severe and warrant close scrutiny; (3) The study reveals a nonlinear relationship between maximum slope displacement and FOS, especially as values approach the limit, characterized by a sharp decline in stability. The findings provide crucial data support and theoretical guidance for slope design, reinforcement measures, groundwater management strategies, and the development of monitoring systems in hazardous areas.

Application of HP-LSTM Models for Groundwater Level Prediction in Karst Regions: A Case Study in Qingzhen City

Groundwater serves as an indispensable global resource, essential for agriculture, industry, and the urban water supply. Predicting the groundwater level in karst regions presents notable challenges due to the intricate geological structures and fluctuating climatic conditions. This study examines Qingzhen City, China, introducing an innovative hybrid model, the Hodrick–Prescott (HP) filter–Long Short-Term Memory (LSTM) network (HP-LSTM), which integrates the HP filter with the LSTM network to enhance the precision of groundwater level forecasting. By attenuating short-term noise, the HP-LSTM model improves the long-term trend prediction accuracy. Findings reveal that the HP-LSTM model significantly outperformed the conventional LSTM, attaining R2 values of 0.99, 0.96, and 0.98 on the training, validation, and test datasets, respectively, in contrast to LSTM values of 0.92, 0.76, and 0.95. The HP-LSTM model achieved an RMSE of 0.0276 and a MAPE of 2.92% on the test set, significantly outperforming the LSTM model (RMSE: 0.1149; MAPE: 9.14%) in capturing long-term patterns and reducing short-term fluctuations. While the LSTM model is effective at modeling short-term dynamics, it is more prone to noise, resulting in greater prediction errors. Overall, the HP-LSTM model demonstrates superior robustness for long-term groundwater level prediction, whereas the LSTM model may be better suited for scenarios requiring rapid adaptation to short-term variations. Selecting an appropriate model tailored to specific predictive needs can thus optimize groundwater management strategies.

Integrating MODFLOW and LSTM models for enhanced groundwater management in the coastal plains of Lattakia Governorate

ABSTRACT Effective groundwater management is vital for ensuring the sustainability of water resources, particularly in regions with significant agricultural and residential demands. This study focuses on the coastal plain of Lattakia Governorate, a 140-km2 area southeast of Lattakia city, bounded by the Mediterranean Sea, the Al-Kabir Al-Shamali River, and the Al-Sanobar River. The objective was to evaluate the performance of the MODFLOW model, within the Groundwater Modeling System (GMS), for simulating groundwater levels and to assess the predictive capabilities of Long Short-Term Memory (LSTM) networks for forecasting temporal changes in groundwater levels. The methodology involved data collection from thirty observation wells, preprocessing for model calibration, and the integration of MODFLOW and LSTM outputs to create a hybrid framework. Findings indicate that MODFLOW effectively simulates physical groundwater processes, while LSTM captures nonlinear and temporal dynamics. The integration of these models reduced prediction errors by up to 20% compared to standalone approaches, enhancing prediction accuracy and reliability. This study provides a novel approach to groundwater management, offering actionable insights for sustainable agricultural practices, residential water security, and pollution mitigation. The proposed framework demonstrates scalability and adaptability to similar hydrological settings globally, contributing to the advancement of integrated groundwater management strategies.

QGIS: an effective tool in assessing the quantity and quality of groundwater resources

ABSTRACT The study demonstrates the utilization of the Quantum Geographic Information System (QGIS) package, an open-source geographic information system (GIS) tool for evaluating the quantity and quality of groundwater resources. This research employed data from public sources pertaining to several sampling stations in the Indian city of Dehradun as its case study and converted this information into a digitized format. The use of QGIS allows for processing and analysis of huge data, leading to the creation of informative maps that depict the spatial distribution of groundwater characteristics. By employing spatial analysis techniques, the study aimed to gain insights into the state of groundwater resources, including their availability, variations in level, and suitability for drinking and irrigation purposes. By visualizing and analyzing the groundwater data using QGIS, the study contributes to the broader goal of managing water resources efficiently and helps policymakers, water resource managers, and other stakeholders make informed decisions regarding groundwater management, allocation, and conservation strategies.

Evaluation of Aquifer Protective Capacity Using Electrical Resistivity Method

This study investigates the groundwater potential of Osun State University, Osogbo campus, through an electrical resistivity survey. Using 30 Vertical Electrical Sounding (VES) points and the Schlumberger array method, geoelectric parameters such as longitudinal conductance, reflection coefficient, and overburden thickness were analyzed. The resistivity data revealed ten distinct curve types with the H curve type being the most prevalent, representing 30% of the total. The subsurface was characterized by 3 to 5 distinct layers, including topsoil, weathered layers (sandy, clayey, or lateritic), fractured basement, and fresh basement. Results showed a wide range of aquifer protective capacities. Approximately 30% of the VES points exhibited poor protective capacity, while 16.66% showed weak protection. Moderate protection was observed in 6.66% of the points, and fairly good protection in 16.67%. The remaining 13.33% had good protection, with only 3.3% rated as very good. Longitudinal unit conductance values ranged from 0.0563 to 1.1427, confirming the predominance of weak to moderate aquifer protection. Aquifers with low reflection coefficient values (r &lt; 0.8) indicated a favourable groundwater potential but increased vulnerability to contamination. This suggests that while certain areas of the campus are vulnerable to contamination, others may offer better protection for long-term groundwater storage and use. The study underscores the importance of tailored groundwater management strategies, particularly given the rapid population growth and industrial expansion in the region, which could introduce future contamination risks. These findings are crucial for sustainable groundwater management in the campus area, ensuring protection against future contamination threats.

Groundwater Potential Assessment Using Integrated Geospatial and Analytic Hierarchy Process Techniques (AHP) in Chemoga Watershed, Upper Blue Nile Basin, Ethiopia

Groundwater is an invaluable natural resource that sustains human life and supports the economic development of nations. However, its unsustainable utilization has emerged as a critical issue, particularly in developing countries. This study investigates the groundwater potential of the Chemoga watershed to address these challenges. Conventional groundwater assessments have typically relied on labor-intensive and time-consuming field surveys, which are resource-demanding and often fail to provide accurate estimates due to the inherent complexity of groundwater systems. In response, this research utilizes geospatial and analytic hierarchy process (AHP) techniques to assess groundwater potential in the Chemoga Watershed, aiming to overcome these challenges. Eight critical biophysical and environmental factors: geology, slope, rainfall, land use/land cover (LULC), soil type, elevation, lineament density, and drainage density were selected for analysis using Saaty’s AHP methodology. Data was gathered from satellite imagery, existing thematic maps, local water offices, and national meteorological agencies. The integration of these thematic maps was performed through a weighted overlay analysis using ArcGIS 10.8, which resulted in the delineation of groundwater potential zones (GWPZ). The model was validated by cross-referencing the generated GWPZ with existing data from dug wells and boreholes. The results reveal five groundwater potential zones: very high (0.73%), high (24.39%), moderate (43.38%), poor (31.25%), and very poor (0.25%). The most suitable zones are in the south, southeast, and southwest of the watershed, particularly near Debre Markos Town. These high-potential zones were validated with a significant 81.5% match to ground truth data from shallow wells. The findings of this study provide crucial insights for decision-makers, enabling the formulation of more effective groundwater management strategies. By identifying cost-effective and suitable well sites, this research contributes to ensuring a sustainable water supply for Debre Markos Town.

Spatial Distribution and Mechanisms of Groundwater Hardness in the Plain Area of Tangshan City, China

Groundwater resources play a critical role in meeting the agricultural, industrial, and domestic water demands of Tangshan, a key industrial city in China. However, with the acceleration of urbanization and the overextraction of groundwater, issues related to groundwater quality have become increasingly apparent. Notably, groundwater hardness has steadily increased over the years, posing risks to human health and elevating industrial water treatment costs. This study analyzed the spatial distribution characteristics and causes of groundwater hardness using 214 groundwater quality samples collected in 2022 from the plain area of Tangshan City, employing inverse distance weighting (IDW), Gibbs diagrams, ion ratios, mineral saturation indices, and Pearson correlation analysis. The results indicate that, in horizontal distribution, high-hardness groundwater is predominantly concentrated in the southern coastal plain area, with hardness gradually decreasing from south to north. Vertically, shallow groundwater in the coastal plain exhibits significantly higher hardness than deep groundwater, with a non-compliance rate of 94.12%, while deep groundwater hardness remains markedly lower. Mid-depth groundwater (60–300 m) in the alluvial plain exhibits elevated hardness, primarily attributed to mineral dissolution and agricultural irrigation return flow. The spatial distribution pattern of groundwater hardness across the study area is predominantly governed by hydrogeochemical processes and hydrochemical environmental factors, with cation exchange adsorption and evaporation–concentration processes identified as the dominant influences. The analysis of ion sources indicates that Ca2+ and Mg2+, the primary contributors to groundwater hardness in the area, are mainly derived from the weathering and dissolution of carbonate minerals, sulfate minerals, and cation exchange processes. Therefore, an in-depth investigation into the spatial distribution and driving factors of groundwater hardness in Tangshan can provide a scientific basis for regional water resource management, pollution control, and water quality optimization. Such research also supports the development of sustainable groundwater management and optimization strategies.

Efficacy of mitigation strategies for aquifer sustainability under climate change

Groundwater systems play a pivotal role in ensuring food and water security while maintaining vital ecosystem functions. The depletion of numerous global aquifers, however, raises concerns regarding the sustainability of groundwater withdrawals and environmental flows. Despite efforts to mitigate this decline, there remains a striking gap in proving the effectiveness of these measures. Our research focuses on the karstic Edwards Aquifer system in Texas to assess how effectively current mitigation strategies are protecting groundwater levels and spring flows, which are essential for biodiversity and water security. Using counterfactual artificial intelligence, we address the critical question: ‘What would have happened and may happen in the absence of the mitigation measures?’. This approach offers deep insights into both historical impacts and future projections under intermediate- and high-emission climate scenarios. By simulating what might have happened and could happen in the future without these mitigation measures, our approach provides a robust analysis of the real-world benefits of groundwater management strategies, highlighting their role in enhancing climate resilience and ensuring the sustainability of aquifers.

Simulating groundwater flow and contaminant transport

This study presents a comprehensive simulation of groundwater flow and contaminant transport using advanced numerical modeling techniques. The research focuses on understanding the complex interactions between groundwater movement and pollutant dispersion across various geological settings. By applying the governing equations of fluid dynamics and solute transport, the model incorporates essential parameters such as hydraulic conductivity, porosity, and dispersivity, enabling the accurate prediction of contaminant behavior over time. Simulations were carried out under a range of scenarios to assess the effects of differing recharge rates and contaminant source configurations on groundwater quality. The results provide critical insights into the mechanisms governing contaminant migration, highlighting the importance of soil properties, boundary conditions, and flow dynamics in influencing transport behavior. Moreover, the study demonstrates how variations in geological features and pollutant sources can significantly alter contaminant dispersal patterns. This work contributes to the development of robust groundwater management strategies and emphasizes the role of simulation tools in assessing environmental risks tied to groundwater contamination.