Search Results (3,206)

Water security is a significant challenge for the Saudi Arabia Kingdom’s development and stability, affecting other economic sectors beyond the water sector. Insufficient water resources are causing economic and social crises; addressing this issue is crucial for the country’s growth and stability. This study aims to manage water resources in central Saudi Arabia (Wadi AS SAHBAA) through a two-level approach. The first level involves extracting rainfall amounts from satellite imagery to predict future rainfall intensity using PERSIANN-CCS-CDR data. The second level focuses on monitoring groundwater recharge using geographic information systems (GIS) and remote sensing techniques. The study further seeks to understand rainstorm behavior influenced by climate variability and applies geomatics techniques for quantitative analysis. The results show that the Wadi AS SAHBAA basin receives an annual precipitation of 116.6 mm/year and mean annual precipitation of 9.7 mm. The year 2019 experienced the highest recorded precipitation, reaching 222.3 mm and mean annual precipitation of 18.5 mm. Between 2013 and 2019, the AS SAHBAA region experienced increased rainfall driven by intense storm events; however, it declined during the period 2020–2022. Moreover, 2021 recorded the lowest annual precipitation of 53.8 mm with mean annual precipitation of (4.5 mm), possibly linked to reduced storm activity due to the COVID-19 pandemic. The study uses several methods to estimate groundwater recharge from rainfall and concludes that the average infiltration during 2013–2022 was varying from 1.59–36.63 mm, representing about between 1.03 and 28.5% of total rainfall. This is reflected in groundwater storage capacity, which ranges from approximately 1.65 to 38.27 million m³ yearly. This study provides a framework for monitoring precipitation and groundwater recharge and offers practical recommendations for regional development and sustainable water management. Full article

The Middle Route of the South-to-North Water Diversion Project (SNWD-MR) serves as a strategic infrastructure critical to safeguarding water security in Northern China. Traversing complex geographical units, the project is perpetually exposed to long-term risks of land subsidence. Conventional Interferometric Synthetic Aperture Radar (InSAR) monitoring is hampered by waterbody isolation, causing spatial discontinuities in the retrieved deformation fields; furthermore, relying solely on deformation metrics fails to comprehensively quantify multidimensional risks. To address these issues, this study proposes an integrated assessment framework that couples time-series InSAR observations with the Analytic Hierarchy Process-Fuzzy Comprehensive Evaluation (AHP-FCE) model. To specifically mitigate the challenge of waterbody isolation, we developed a connectivity-aware multiscale down-sampling phase unwrapping strategy. By exploiting cross-canal bridges to construct a spatial connection network, a highly accurate, spatiotemporally continuous deformation field across the entire alignment was successfully reconstructed. Using the derived deformation field as the core dynamic indicator, an AHP-FCE model integrating hydrogeological features and human perturbations was constructed. A complementary evaluation process comprising sensitivity analysis and an internal physical consistency assessment was subsequently implemented. The results demonstrate that (1) the proposed algorithm effectively resolves the spatial discontinuity issue of the cross-canal deformation fields, reducing the deformation-velocity RMSE from 7.9 to 5.7 mm/y, corresponding to an approximately 27.8% reduction in RMSE relative to the traditional Minimum Cost Flow (MCF) method; (2) land subsidence along the alignment exhibits prominent spatial heterogeneity, with the northern Henan and southern Hebei sections identified as very-high-risk zones; and (3) InSAR deformation magnitude and the groundwater elevation indicator emerge as the most influential factors in the modeled risk distribution. Overall, this study expands conventional deformation monitoring into a systematic, quantitative risk assessment framework, thereby providing scientific insights and theoretical support for the early warning of geo-hazards and the smart operation and maintenance of large-scale water diversion projects. Full article

Renewable-powered agricultural water systems are often assessed as solar-pumping devices, but their sustainability depends on a service chain linking crop-water demand, hydraulic duty point, power electronics, storage, water quality, governance, operation and end-of-life management. This structured integrative review synthesizes peer-reviewed and practice-oriented evidence on photovoltaic pumping, hybrid renewable irrigation, grid-interactive pumps, micro-hydro assistance and renewable-powered brackish-water reverse osmosis (PV-RO). Evidence was screened across four source families and coded by service function, energy architecture, hydraulic duty and dominant sustainability pathway; recurring combinations were consolidated using explicit separation and merge rules. It develops an archetype-based screening framework for ex ante appraisal of irrigation, desalination and circularity risks. Seven technology-service archetypes are identified: direct PV pumping, PV-to-tank pumping, PV with electrical buffering, grid-interactive PV pumping, PV–wind hybrid irrigation, micro-hydro-assisted irrigation and PV-RO water making. The framework links each archetype to its operating envelope, evidence maturity, enabling subsystems, sustainability pathways, minimum indicators and ordinal triggers for deeper due diligence. Hydraulic storage is usually the lowest-regret reliability buffer for open-field irrigation, whereas batteries are justified mainly when pressure stability, fertigation timing or night-time operation has high agronomic value. PV-RO is a distinct water-making archetype and is environmentally defensible only where feed-water characterization, energy recovery, pretreatment, product-water agronomy, membrane management and permitted concentrate disposal are embedded in design. Two synthetic applications demonstrate archetype selection and due-diligence escalation. Responsible deployment requires service-oriented screening that integrates hydraulic design, groundwater governance, procurement quality assurance, circularity obligations and social inclusion before field implementation. Full article

Climate change and sea-level rise are expected to intensify groundwater salinization in coastal aquifers, yet their relative contributions remain insufficiently quantified. This study developed a MODFLOW–SEAWAT model to compare the combined impacts of future precipitation change and sea-level rise on groundwater salinization in a representative coastal aquifer of the Pearl River Delta (PRD), China. The groundwater-flow component was calibrated using heads from 54 observation wells (R² = 0.878, RMSE = 0.699 m), and the initial salinity field was constructed and spatially evaluated using chloride concentrations from 142 sampling sites. Four scenarios, including baseline, sea-level rise, future precipitation (SSP5-8.5), and their combination, were simulated over 30- and 60-year periods. The scenario comparison indicates that sea-level rise alone slightly increases groundwater salinity, whereas the selected SSP5-8.5 precipitation series produces a stronger response through recharge and freshwater dilution. Under the SSP5-8.5 scenario, the combined area of high-salinity groundwater (Degrees IV and V) after 60 years decreases by approximately 50% compared with the baseline scenario. The combined scenario exhibits salinization patterns similar to those of the precipitation scenario, indicating that precipitation change has a stronger influence than sea-level rise under the selected scenario and hydrogeological conditions of the PRD. These findings suggest that targeted artificial recharge in recharge-sensitive inland transition zones could help mitigate groundwater salinization and support climate adaptation in coastal regions. Full article

Landslides in weathered gypsum deposits present significant geotechnical challenges because progressive weathering, groundwater fluctuations, and residual strength degradation strongly influence slope stability. This study investigates the failure mechanism and remediation of a large translational landslide in weathered gypsum deposits in Çankırı, Türkiye. An integrated engineering geological assessment was conducted using data from 16 boreholes, laboratory tests, and groundwater/inclinometer monitoring records, followed by residual shear strength back-analysis and slope stability evaluation. A three-dimensional geological model was developed, and cross-sections were analyzed using the Morgenstern–Price limit-equilibrium method. Back-analysis identified residual shear strength parameters of c′ = 7.5 kPa and ϕ′ = 10° for the weathered gypsum, while laboratory direct shear tests yielded c′ = 4.0 kPa and ϕ′ = 9.9°. The friction angles obtained from the two approaches are nearly identical, whereas the back-calculated cohesion is slightly higher than the laboratory-derived value. Back-analysis parameters were used to design remediation measures, including slope unloading, rock buttress construction, toe fill improvement, and surface/subsurface drainage. Stability analyses increased the factor of safety to 1.76 under static loading, while pseudo-static analyses satisfied the recommended seismic design criterion (FS ≥ 1.10). Equivalent-linear Newmark analyses predicted a permanent displacement of 15 cm, within acceptable limits. The methodology provides a practical framework for assessing and stabilizing landslides developed in weathered gypsum deposits in seismically active regions. Full article

Numerous studies have examined the contribution of polycyclic aromatic hydrocarbons (PAHs) to soil contamination, resulting from legacy oil extraction and storage activities in the energy sector, and the human health risks. In this research, a human health risk assessment (HHRA) was performed on a site contaminated with crude oil, incorporating spatial analysis to identify hotspots of carcinogenic and non-carcinogenic risk from PAH-contaminated soil. In total, eight soil sampling locations were considered. The HHRA was conducted using a software tool developed by the National University of Science and Technology POLIETHNICA of Bucharest according to the United States Environmental Protection Agency (US EPA) and American Society for Testing and Materials (ASTM International) standards. The results obtained in the current assessment were validated against the Risk-net software 3.2 (an Italian tool for risk assessment validated by the ISPRA). The assessment considered a residential scenario (adult and child receptors) using four different exposure pathways: soil ingestion, dermal contact, vapor inhalation (due to the volatilization process) and groundwater ingestion (because of the leaching process). The carcinogenic risk (CR = 1 × 10⁻⁵) and total hazard index (THI < 1) in the studied area were above the threshold values for both adults’ and children’s receptors. The highest concern is given to the process of PAHs leaching from soil to groundwater. The highest carcinogenic concern is benzo(a)pyrene for children’s exposure via groundwater ingestion (CR = 3.53 × 10⁻⁵), while the highest toxic effect is registered for the contaminant naphthalene (THI = 6.22) for the same receptor and exposure pathway. Full article

Henan Province, a major coal producing region in China, faces severe surface subsidence induced by extensive underground mining, which compromises regional ecological security and infrastructure stability. In this study, small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) was applied to Sentinel-1A imagery acquired from March 2017 to February 2025 to characterize surface deformation in concentrated coal mining areas. A local validation was conducted within a representative mining area in Study Area 3 using measurements from 14 leveling benchmarks acquired between 5 May and 20 July 2023. The comparison yielded an $R^2$ of 0.816 and an RMSE of 9.22 mm, indicating good agreement between the SBAS-InSAR and leveling measurements during the validation interval. The subsidence in the study area exhibits significant spatial heterogeneity and continuous accumulation characteristics. The most negative approximate vertically projected deformation rate reached −371 mm/yr, and the maximum cumulative displacement reached −2101 mm. Scenario-based sensitivity analysis indicated potential projection errors of 6.76–8.34% for a horizontal-to-vertical displacement ratio of 0.10 and 20.28–25.01% for a ratio of 0.30, with larger uncertainty expected near subsidence trough margins. Given the difficulty of quantifying large-scale underground mining parameters, this study employs multisource environmental and topographic variables as auxiliary indicators and develops an XGBoost-SHAP model to evaluate their relative explanatory contributions to the spatial heterogeneity of mining-induced subsidence. Among the selected measurable environmental and topographic variables, groundwater table depth represents the most important measurable explanatory factor for the spatial heterogeneity of subsidence, with distinct response patterns between plain areas with thick unconsolidated layers and piedmont bedrock regions. Furthermore, wavelet coherence analysis identifies scale-dependent spatial associations between topography and subsidence. At the regional scale, elevation exhibits spatial correspondence with the geomorphological framework of contiguous subsidence basins. At the local scale, slope and aspect show localized associations with differential deformation gradients near the margins of subsidence troughs. Full article

Estimating transmissivity and hydraulic conductivity is crucial for groundwater resource assessment, flow modeling, pollution remediation, and sustainability studies. In the volcanic highlands of Ethiopia, millions rely on hand-dug wells and springs for drinking and irrigation, yet the hydraulic properties of these shallow aquifers remain largely uncharacterized. This study provides the first comprehensive estimation of transmissivity and hydraulic conductivity for the shallow groundwater aquifers in the Lake Tana Basin through integrated analyses of pumping and slug tests. The effective dataset comprised 31 tests, unevenly distributed among four aquifer types: eight in Quaternary basalt, 13 in weathered basalt regolith, seven in pyroclastic deposits, and three in alluvio-lacustrine sediments. Time-series groundwater level data were additionally used to characterize seasonal recharge responses and recession behaviors. Quaternary basalt aquifers showed high transmissivity values of 117–1064 m²/d, with a geometric mean of 235 m²/d, reflecting the influence of open and hydraulically connected fractures. Weathered basalt regolith aquifers had transmissivity values of 0.27–71 m²/d, with a geometric mean of 3.09 m²/d, whereas pyroclastic aquifers ranged from 0.17 to 11 m²/d, with a geometric mean of 0.96 m²/d. The alluvio-lacustrine aquifers ranged from 1.68 to 173 m/d, with a geometric mean of 8.56 m²/d; however, this estimate should be interpreted cautiously because it is based on only three tests. This study reveals strong heterogeneity within and across aquifers. Pumping tests were generally more applicable to the relatively transmissive Quaternary basalt aquifers, whereas slug tests provided a practical approach for characterizing shallow weathered regolith, pyroclastic, and alluvio-lacustrine aquifers. Seasonal groundwater level patterns varied with geology and topographic position: aquifers on slopes and plateaus generally showed rapid recharge and recession responses, whereas those at foothills and floodplains exhibited more sustained groundwater levels, probably because of lateral inflow and interactions with river water. The findings provide preliminary hydraulic-property ranges for groundwater assessment and indicate that fractured Quaternary basalt aquifers may represent promising targets for water-supply development. Full article

Groundwater-storage anomalies (GWSA) derived from the Gravity Recovery and Climate Experiment (GRACE) mission provide valuable information for regional groundwater monitoring. Improving the spatial representation and temporal continuity of GRACE-derived GWSA is important for supporting groundwater assessment at subregional scales. A sequential framework combining Gaussian Process (GP) temporal gap filling and Random Forest (RF) spatial downscaling was developed for GWSA reconstruction in Henan Province, China, during 2002–2022. The GP model was used to reconstruct missing observations and characterize temporal variations, while the RF model statistically redistributed the GRACE-based GWSA signal using multi-source hydroclimatic predictors. The resulting dataset comprises model-derived GWSA estimates on a 1 km output grid constrained by the coarse spatial support of GRACE observations and the relationships learned from the auxiliary variables. Therefore, the 1 km grid spacing should not be interpreted as an independent 1 km resolving capability for groundwater-storage variations. Agreement with the parent GRACE-based GWSA product was used to assess coarse-scale reconstruction consistency rather than independent fine-scale accuracy. Comparison with groundwater-level anomalies from 63 monitoring wells yielded a correlation coefficient of 0.88, indicating temporal agreement at the sampled locations. Because the groundwater-level observations were not converted into storage anomalies using specific yield, this comparison does not establish absolute GWSA accuracy or independently validate the model-derived fine-scale spatial patterns. The reconstructed estimates revealed pronounced spatial heterogeneity in groundwater-storage changes, with persistent depletion concentrated in northern Henan, where groundwater decline rates exceeded 20 mm yr⁻¹. Overall, the framework improved the temporal continuity and spatial representation of GRACE-based groundwater-storage estimates while retaining the fundamental spatial constraints of satellite gravimetry. The results demonstrate the potential of integrating GRACE observations, machine learning, and multi-source Earth observation data to support regional groundwater assessment. Full article

The hydrogen economy has emerged as a promising pathway to address climate change and ensure long-term global energy security, with water electrolysis powered by renewable energy as a key enabler of sustainable hydrogen production. Recent advances in various electrolyser technologies have enhanced their suitability for industrial applications, creating new opportunities for deploying green hydrogen. To address the gap in integrated, multi-dimensional assessment tools for groundwater-based hydrogen systems in water-scarce developing countries, this study develops and presents a Structured Assessment Framework for Green Hydrogen Production from Groundwater in South Africa—the first framework to simultaneously integrate hydrogeological sustainability screening, electrolyser technology selection under groundwater quality constraints, disaggregated levelised cost of hydrogen (LCOH) analysis including water treatment costs, comparative life cycle assessment (LCA) of green, blue, and grey hydrogen pathways, and policy and governance alignment within a single operationalised architecture. This included integrating five thematic dimensions: groundwater resource assessment, electrolyser technology integration, economic viability, environmental sustainability, and policy and governance considerations. This systematic review was conducted in accordance with the PRISMA 2020 guidelines, drawing on 130 studies retrieved from Scopus and Web of Science (2015–2025). The analysis examines groundwater quality and suitability, the technical feasibility of electrolyser systems, and the comparative implications of grey, blue, and green hydrogen pathways on cost and environmental performance. The framework also provides strategic guidance for deploying renewable-energy-powered hydrogen systems, emphasising life-cycle impacts, regulatory alignment, and the potential for decentralised hydrogen hubs. Findings highlight the significance of strengths, weaknesses, opportunities, and threats (SWOT) for green hydrogen production using groundwater in South Africa, including export potential and strong linkages to the circular economy. The study offers actionable insights for policymakers, planners, and industry stakeholders seeking to advance a sustainable and economically competitive hydrogen landscape. Full article

Climate change is altering global temperature and precipitation patterns, with particularly strong effects expected in Mediterranean regions, where reduced groundwater recharge and increased evapotranspiration may affect groundwater-dependent ecosystems. This study provides a preliminary, indicator-based assessment of the potential sensitivity of the Cabecera del Bornova Groundwater Body (Guadalajara, Spain), which sustains the Somolinos karst wetland, under natural conditions and protected as a Natural Groundwater Reserve and Natural Lacustrine Reserve. Empirical correlations were established between accumulated deviations of historical precipitation and observed piezometric levels in two monitoring piezometers using second-degree polynomial functions. The most informative relationships were obtained for piezometer ZE01, particularly at the daily scale, whereas the second piezometer showed weaker relationships. These functions were applied to regionalized climate projections generated with the FICLIMA methodology from ten CMIP6 models under SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5 scenarios from the IPCC Sixth Assessment Report. The results indicate a general decreasing tendency in empirical piezometric-level indicators throughout the 21st century, although the magnitude of the response is highly sensitive to the selected rainfall station, temporal resolution, climate model and scenario. Extreme projected declines are interpreted as extrapolation-sensitive outputs rather than deterministic predictions of aquifer drawdown or groundwater-reserve depletion. Direct impacts on lagoon level, spring discharge or wetland extent cannot be quantified with the dataset. The results highlight the need to expand piezometric monitoring, instrument the Manadero del Bornova spring, monitor lagoon water levels and develop physically based recharge and groundwater-flow models. Full article

Groundwater in northeastern China is characterized by low temperature and the coexistence of manganese (Mn), ammoniacal nitrogen, and organic pollutants, resulting in prolonged start-up of biological Mn removal filters. To address this challenge, combined bioaugmentation with heterotrophic nitrifying bacteria (HNB) and manganese-oxidizing bacteria (MnOB) was employed. The optimal inoculation ratio was determined, and the effects of manganese sand and activated carbon on Mn and ammoniacal nitrogen removal were evaluated. Under bioaugmentation conditions, manganese sand promoted the rapid establishment of ammonia oxidation, whereas activated carbon exhibited superior Mn²⁺ oxidation performance. A dual-media filter consisting of an upper manganese sand layer and a lower activated carbon layer was subsequently developed. Compared with the conventional manganese sand filter, the bioaugmented composite filter shortened the start-up period by 21 days and reached stable operation on day 24. High-throughput 16S rRNA gene sequencing revealed that activated carbon enriched norank_f__Beggiatoaceae and enhanced synergistic interactions among functional microbial groups. This study provides a promising strategy for the efficient simultaneous removal of Mn and ammoniacal nitrogen from groundwater in cold regions. Full article

Assessing long-term hydroclimatic variability in central Mexico is essential to understand regional water availability and groundwater recharge for urban centers such as Querétaro. This study developed a multi-century winter–spring precipitation reconstruction for the Sierra Gorda Biosphere Reserve (SGBR) using ring width chronologies of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco. Standard dendrochronological techniques were applied to develop a 284-year master chronology (1731–2015). Following the accepted Subsample Signal Strength criterion (SSS ≥ 0.85) for chronology reliability, the reconstruction was restricted to the 1744–2015 period, yielding a statistically robust 271-year December–April precipitation record. A bootstrapped ordinary least-squares regression model relating tree-ring indices to instrumental December–April precipitation was calibrated and validated using split-sample cross-validation, explaining 46% of the instrumental precipitation variance (R² = 0.46) and yielding positive verification statistics (RE = 0.38–0.58; CE = 0.37–0.57). Spatial field correlations against gridded climate data (CRU TS4.08) confirmed a broad regional hydroclimatic signal centered over the Sierra Madre Oriental. Continuous wavelet transform (CWT), spectral analysis, superposed epoch analysis (SEA), and wavelet coherence (WTC) revealed significant interannual (2–8 years) and decadal (10–20 years) variability associated with large-scale ocean–atmosphere climate modes, including the El Niño–Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO), and Tropical North Atlantic (TNA) index. The pronounced sensitivity of these conifer forests to pre-monsoonal moisture deficits highlights their vulnerability to projected warming and increasing spring evapotranspiration stress. Although the reconstruction is limited to pre-monsoonal (December–April) precipitation, it provides a robust centuries-long baseline for contextualizing regional hydroclimatic variability and supports water-resource management, groundwater conservation, and climate-adaptation strategies in central Mexico. Full article

4-Chlorophenol (4-CP) is a persistent and highly toxic pollutant commonly found in groundwater. However, its efficient degradation remains challenging due to the rapid agglomeration of conventional zero-valent iron (ZVI) nanoparticles, their narrow pH operating range, and the environmental risks associated with synthetic chelating agents. To address these limitations, this study presents a rationally designed catalytic system integrating cyclodextrin polymer (CDP)-supported bimetallic Cu-Fe nanoparticles (Cu-Fe-CDP) with citric acid (CA) as a green complexing agent. The porous CDP matrix effectively mitigates nanoparticle agglomeration and provides abundant active sites, while the Fe-Cu bimetallic coupling accelerates electron transfer and iron corrosion. Critically, CA acts as a biocompatible ligand that sustains Fe(II)/Fe(III) redox cycling, expands the effective pH range, and enhances hydroxyl radical (·OH) generation. The system achieves 92.13% degradation of 4-CP within 80 min at pH 9.0 and nearly complete removal at pH values between 3.0 and 7.0. Mechanistic studies, including electron paramagnetic resonance (EPR) spectroscopy and radical quenching tests, confirm the dominance of ·OH radicals (82.67% inhibition by TBA) and the essential role of surface Fe(II)/Fe(III) cycling. The catalyst exhibits excellent reusability, broad-spectrum activity toward multiple pollutants, and sustained performance in real water matrices and long-term column tests with minimal metal leaching. This work demonstrates a chemically robust strategy for chlorophenol remediation using green citric acid and biodegradable CDP without exogenous oxidant addition, showing promise for further development toward practical applications. Full article

Clay slopes are particularly sensitive to variations in soil strength, groundwater conditions, and slope geometry, making their rapid and reliable assessment essential for geotechnical design, landslide prevention, and infrastructure risk management. This study develops and evaluates an empirical express method for estimating the stability of clay slopes based on the relationship between soil mechanical parameters, slip surface geometry, and the factor of safety. The proposed approach derives empirical dependencies for the radius of the potential circular slip surface and the coordinates of its centre as functions of slope height, cohesion, internal friction angle, and water-related conditions. The method is supported by long-term field observations and geotechnical investigations of clay slopes, including dry and water-affected scenarios. Two representative stability conditions are considered: dry slopes and slopes influenced by an elevated depression curve. The method was evaluated for 45° clay slopes with heights up to 60 m, using eight representative cases: four dry scenarios and four water-affected scenarios. The calculated factors of safety were compared with GEO5 SLOPE results obtained using Bishop’s simplified method. The comparison showed that most analysed cases presented differences below 5% between the proposed express method and the Bishop-based numerical benchmark, with larger deviations occurring only in selected boundary cases. The results demonstrate that the proposed method can provide a rapid preliminary assessment of clay slope stability, supporting early-stage geotechnical diagnosis, risk screening, and decision-making in regions where clayey formations and slope instability are recurrent. Full article