Search Results (387)

Ground subsidence is a significant geotechnical hazard in urban areas, leading to property damage, casualties, and broader societal issues. This study investigates the mechanisms of cavity formation and ground subsidence through laboratory model tests using Korean standard sand and marine clay under controlled conditions. A transparent soil box apparatus was fabricated to simulate sewer pipe damage, with model grounds prepared at various relative densities, groundwater levels, and fines contents. The progression of cavity formation and surface collapse was observed and quantitatively analyzed by measuring the time to cavity formation and ground subsidence, as well as the mass of discharged soil. Results indicate that lower relative density accelerates ground subsidence, whereas higher density increases cavity volume due to greater frictional resistance. Notably, as the fines content increased, a tendency was observed for ground subsidence to be increasingly suppressed, suggesting that cohesive clay particles can limit soil loss under seepage conditions. These findings provide valuable insights for selecting backfill materials and managing subsurface conditions to mitigate ground subsidence risks in urban infrastructure. Full article

Mine water treatment and emissions have become important factors that restrict the comprehensive benefits of coal enterprises and local economic development, and the use of the deep well recharge method can address the specific conditions of mine surge water. This paper takes the actual situation of coal mine water treatment as an example and innovatively carries out dynamic tests for the Ordovician limestone aquifers deep in the mine. Intermittent reinjection test shows that under the same reinjection time, the water level recovery rate during the intermittent period is fast at first and then slow. Moreover, the recovery speed of the water level buried depth slows down with the increase in the reinjection time, which reveals the characteristics of the water level rising rapidly and recovering quickly during the reinjection of the reservoir. The average formation water absorption index is 420.81 m³/h·MPa. The water level buried depth of the long-term reinjection test showed three stages (rapid rise, slow rise, and stable stages), and the water level buried depth was raised to 1.52 m at its highest. Monitoring data from the surrounding 5 km area showed that reinjection did not affect aquifer water levels, verifying the excellent storage capacity of the deep Ordovician fissure-karst aquifer. The variability of well loss under pumping and injection conditions was comparatively analyzed, and the well loss produced by the recharge test was 4.06 times higher than that of the pumping test, which provided theoretical support for the calculation of hydrogeological parameters to eliminate the influence of well loss. This study deepens the understanding of Ordovician limestone aquifers in deep mine water, providing a reference for cheap mine water treatment and sustainable groundwater management in similar mine areas. Full article

The Yellow River Basin (YRB) is a critical ecological zone in China now confronting growing tensions between land conservation and development. This study combines land use, climate, and socio-economic data with spatial–statistical models (GeoDetector [GD]–Patch-generating Land Use Simulation [PLUS]–Integrated Valuation of Ecosystem Services and Trade-Offs [InVEST]) to analyze land use changes (2000–2020), evaluate habitat quality, and simulate scenarios to 2040. Key results include the following: (1) Farmland was decreased by the conversion to forests (+3475 km²) and grasslands (+4522 km²), while construction land expanded rapidly (+11,166 km²); (2) the population and Gross Domestic Product (GDP) pressures drove the farmland loss (q = 0.148 for population, q = 0.129 for GDP), while synergies between evapotranspiration (ET) and the Normalized Difference Vegetation Index (NDVI) promoted forest/grassland recovery (q = 0.155); and (3) ecological protection scenarios increased the grassland area by 12.94% but restricted the construction land growth (−13.84%), with persistent unused land (>3.61% in Inner Mongolia) indicating arid-zone risks. The Habitat Quality-Autocorrelated Coupling Index (HQACI) declined from 0.373 (2020) to 0.345–0.349 (2040), which was linked to drought, groundwater loss, and urban expansion. Proposed strategies including riparian corridor protection, adaptive urban zoning, and gradient-based restoration aim to balance ecological and developmental needs, supporting spatial planning and enhancing the basin-wide habitat quality. Full article

Glaciers worldwide are in retreat, and their meltwater can modulate mountain aquifers. We examined whether mass loss of the Juncal Norte Glacier (central Chile) has affected groundwater storage in the Juncal River basin between 1990 and 2022. Recession-curve modeling of daily streamflow shows no statistically significant trend in basin-scale groundwater reserves (τ = 0.06, p > 0.05). In contrast, glacier volume declined significantly (−3.8 hm³/yr, p < 0.05), and precipitation at the nearby Riecillos station fell sharply during the 2008–2017 megadrought (p < 0.05) but exhibited no significant change beforehand. Given the simultaneous decreases in meteoric inputs (rain + snow) and glacier mass, one would expect groundwater storage to decline; its observed stability therefore suggests that enhanced glacier-melt recharge may be temporarily offsetting drier conditions. Isotopic evidence from comparable Andean catchments supports such glacio-groundwater coupling, although time lags of months to years complicate detection with recession models alone. Hence, while our results do not yet demonstrate a direct glacier–groundwater link, they are consistent with the hypothesis that ongoing ice loss is buffering aquifer storage. Longer records and tracer studies are required to verify this mechanism and to inform sustainable water resources planning. Full article

Metformin is the preferred first-line treatment for non-insulin-dependent diabetes mellitus, known for its benefits in cancer suppression, weight loss, and antiketogenic activity. It is a leading drug regarding mass distribution, and its high solubility in water leads to its significant accumulation in surface and groundwater. While some studies have explored its degradation products and toxicological consequences, none have specifically examined the impact of individual natural minerals and their mechanisms leading to these degraded compounds. Our investigation focuses on understanding the mineralogical effects of different photocatalysts and organic matter while assessing acute toxicity through cell viability tests on human cell lines. We utilized a custom-built reactor system containing metformin hydrochloride, photocatalysts, and organic matter under oxidizing conditions to explore the formation of new degraded compounds. We assessed the acute toxicity of both metformin hydrochloride and the resulting chemical mixture on kidney and liver cell lines using the colorimetric MTT cell viability assay. Despite the abundance of surface functional groups in organic humic acid, only solar energy-driven catalysts were found to effectively break down this widely used medication. Comparative analysis of metformin hydrochloride and its degraded residues indicates a toxic effect on liver cells. Our experiments contribute to understanding the environmental fate of metformin and pave the way for further biochemical investigations to identify toxicological mechanisms. Full article

Leaching from cement can lead to a loss in performance and durability and can also have an environmental impact. Therefore, it is an important aspect to consider when new cements are being developed and where concrete is to be placed that could lead to the contamination of groundwater. Calibrated thermodynamic models can provide very useful predictions in a matter of seconds for any cement-based material. However, such models need to include accurate representations of the solid-solution nature of the C-S-H gels that are included for the incongruent dissolution of calcium and silica. This study presents the calibration of a thermodynamic model employing the pH-REdox-Equilibrium geochemical software 3.8.7, written in C (PHREEQC 3.8.7), to model the change in the pH and the leaching of calcium (Ca) and silica (Si) from cement against the Ca/Si ratio and over time. The predicted concentrations of Ca and Si and the pH in the leachate were calculated using three solid-solution C-S-H gel models that were taken from the cemdata18 database, namely, CSHQ, CSH3T, and tobermorite–jennite, which have not been analysed before and show good agreement. The calibrated model was used to predict leaching from a CEM II/A-L cement and a blended CEM I + fly-ash with a cement replacement level of 35%. The effect of a sulphate environment (Na₂SO₄) was also analysed. Full article

Iraq faces significant challenges in sustainable water resource management, due to intensive agriculture and climate change. Modern irrigation leads to depleted natural springs and abandoned traditional canal systems, creating a nexus between climate, water availability, agriculture, and cultural heritage. This work unveils this nexus holistically, from the regional to the local scale, and by considering all the components of the nexus. This is achieved by combining five decades (1974–2024) of satellite data—including declassified HEXAGON KH-9, Copernicus Sentinel-1/2/3, COSMO-SkyMed radar, and PlanetScope’s Dove optical imagery—and on-the-ground observations (photographic and drone surveying). The observed landscape changes are categorised as “proxies” to infer the presence of the given land processes that they correlate to. The whole of southern Iraq is afflicted by dust storms and intense evapotranspiration; new areas are desertifying and thus becoming local sources of dust in the southwest of the Euphrates floodplain and close to the boundary with the western desert. The most severe transformations happened around springs between Najaf Sea and Hammar Lake, where centre-pivot and herringbone irrigation systems fed by pumped groundwater have densified. While several instances of run-off and discharge highlight the loss of water in the western side of the study area, ~5 km² wide clusters of crops in the eastern side suffer from water scarcity and are abandoned. Here, new industrial activities and modern infrastructure have already damaged tens of archaeological sites. Future monitoring based on the identified proxies could help to assess improvements or deterioration, in light of mitigation measures. Full article

Landslides are mass movements of rock, soil, or debris under the influence of gravity. These phenomena occur due to the loss of slope stability or imbalance of external loads. The intensity and consequences of landslides depend on various factors such as topography, geological structure, and precipitation regime. This study investigates the characteristics of rainfall-induced landslides in red basaltic soils on the basis of field investigations, geotechnical surveys, and slope stability modeling under anthropogenic triggers. The results indicate a close relationship between soil moisture and shear strength parameters, which significantly influence slope stability. A real-time observation system recorded groundwater level fluctuation in relation to surface runoff and precipitation rates. It is revealed that intense rainfall and low temperatures regulate soil moisture, resulting in a reduction of cohesion and shear strength parameters. These findings enhance the understanding of landslide mechanism in basaltic soil regions, which are highly sensitive to precipitation. The results also highlight that human activities play a significant role in triggering landslides. Therefore, a real-time monitoring system for rainfall, soil moisture, and groundwater is essential for early warning and supports the integration of smart technologies and Internet of Things (IoT) solutions in natural disaster management. Full article

Deep borehole heat exchangers (DBHEs) have been widely used for extracting geothermal energy in China. However, the application of this technology in an open well with high temperature remains unknown. In this paper, the thermal performance of a DBHE installed in a groundwater-filled hot dry rock (HDR) well in the Gonghe Basin of Qinghai Province in China was investigated. A U-shaped pipe subjected to a hydraulic pressure of 30 MPa and a temperature of 180 °C was tested successfully. Severe heat loss was detected during the test, which might have been due to the pipe not being well-insulated. To better understand the performance of DBHEs, a numerical model was developed. The results indicate that the pipe’s thermal performance increased by 247% using insulation with a 15 mm layer thickness and a thermal conductivity of 0.042 W/m·K. Thermal performance was significantly improved by increasing the fluid flow rate and pipe diameter. Among the different pipe configurations, double U-shaped buried pipes can achieve the highest performance. The heat-specific rate can reach up to 341.33 W/m with a double U-shaped pipe with a diameter of 63 mm. The second highest rate can be achieved with a coaxial pipe, while single U-shaped pipes have the lowest one. Full article

Optimal water resource allocation in agricultural irrigation districts constitutes a core strategy for achieving coordinated regional water–food–ecosystem development. However, current studies rarely integrate inter-basin water diversion projects into the allocation, and the prolonged operation of diversion systems fails to adequately consider their ecological impacts in the irrigation districts. This study incorporates inter-basin water diversion into supply–demand dynamics and considers its influence on groundwater table changes in terrestrial ecological targets. Inexact two-stage stochastic programming (ITSP) was applied for optimal water allocation to address uncertainties from fluctuations in future water availability and interval ambiguity in socioeconomic information. Taking the densely populated agricultural irrigation district of Huaibei as a case study, we established a multi-stakeholder allocation model, considering the Yangtze-to-Huai water diversion project, to maximize comprehensive benefits under multiple scenarios of water availability for the years of 2030 and 2040. The results demonstrate that the district will face escalating water scarcity risks, with demand–supply gaps widening when available water resources decrease. The water redistribution in the second stage reduces scarcity-induced losses, achieving maximum comprehensive benefits. The water diversion project enhances supply capacity and boosts economic gains. The project can also decrease the fluctuation range of the total benefits by 5 × 10⁶ CNY (2030) and 3.4 × 10⁷ CNY (2040), compared with the scenario without the project. From 2030 to 2040, limited water resources will progressively shift toward sectors with higher economic output per unit water, squeezing agricultural allocations. Therefore, for irrigation districts in developing countries, maintaining a minimum guaranteed rate of agricultural water proves critical to safeguarding food security. Full article

This research work investigates the Myki Municipality’s aquifer system in the mountainous region of Xanthi Prefecture, Northeast Greece, with regard to the area’s groundwater exploitation and management requirements for drinking water supply. During the period 2021–2023, the work involved (i) groundwater discharge measurements and groundwater sampling from forty-seven (47) springs and five (5) groundwater wells, followed by groundwater chemical analyses; (ii) appropriate analysis, elaboration, and presentation of the results obtained; and (iii) formulation of related proposals that would improve the conditions of the water supply in the study area. The study revealed that water shortage circumstances exist in the study area, which may be due to low aquifer capacity in some areas, deficient groundwater recovery facilities, and water losses in the water supply network. Full article

Rainfall infiltration and groundwater fluctuations induced by cyclonic rainfall are the main causes of slope failure. Slope stability monitoring is key to preventing and controlling rock slope failure. Aiming at the monitoring theory and technical problems of dam slope failure under a cyclonic rainfall environment, this study carried out a physical model test and numerical simulation on the stability monitoring of the weathering transition zone in rock slopes. The results show that: (1) Under cyclonic rainfall, the increased permeability, the expansion of the rock fracture network, and the decrease of effective stress are the main causes of increased lateral deformation of the slope. (2) Physical model test results showed that rain spatter erosion and runoff erosion could lead to rapid loss of anchor bolt preload. In the hydraulic fluctuation stage, the anchor bolt axial force decreased first, then increased, and finally tended to be stable. The unloading response of the Intelligent Terminal Structure was significant during rock block sliding. In the numerical simulation, the anchor bolt axial force increased continuously with the increase of lateral displacement of slope. (3) By analyzing the evolution of anchor bolt axial force and pore water pressure in the weathering transition zone, a monitoring criterion for the stability of the weathering transition zone of rock slopes based on the Logistic function was proposed. Full article

Efficient and sustainable water management measures are required on Mediterranean islands due to water shortages, which are exacerbated by climatic variability and increased tourist traffic. This study uses a multi-criteria decision analysis (MCDA) approach, specifically Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), to examine and rate water management strategies for three Aegean islands that face significant water shortage: Mykonos, Naxos, and Kos. Three main factors were taken into account in the analysis: preventing groundwater depletion, reducing groundwater deterioration, and managing long-term water demands. Expert questionnaires were used to evaluate eight different alternatives, which included reservoir construction, desalination plants, conserving water in agriculture, and reducing network losses. The results for Mykonos showed specific preferred alternatives, such as desalination plants (R2) and agricultural water conservation (R3), which reflect the island’s low capacity for natural water storage. Constructing reservoirs (R1) and conserving agricultural water (R3) were prioritized in Naxos, showing the significance of storage infrastructure for the island’s large agriculture sector. Kos also supported reservoir construction (R1) and agricultural water conservation (R3), displaying the need for both storage and conservation practices. The least sustainable alternative option on all islands was determined to be water transportation by ship (R8). The present study emphasized the significance of localized projects, the construction of water storage infrastructures, and stakeholder involvement in a comprehensive approach to managing water resources. The results indicate an integrated approach that takes into account infrastructure, conservation, and policy, and they are consistent with previous studies on water management in the Mediterranean. This study highlights the need for adapted combined strategies to achieve sustainable water resource management under climatic variability and offers a framework for managing water shortages in similar regions. Full article

Excessive N loss through leaching and volatilization is a major concern in modern agriculture, reducing N use efficiency, groundwater contamination, and environmental degradation. To address these issues, this research evaluates the impact of N fertilizers containing nitrification inhibitors (NIs), which restrict the conversion of ammonium (NH₄⁺) into nitrate (NO₃⁻), thereby enhancing N retention in the soil. This study examines the effects of different N fertilizer applications on the yield and nutrient dynamics of winter barley (Hordeum vulgare L.) Field experiments were conducted to compare the effects of a one-time and split application of granular N fertilizers ENSIN (with NIs) and DASA (without NIs) on winter barley yield and N dynamics. The highest grain yield was observed with a single ENSIN application (8.35 Mg.hm⁻²), followed by a divided DASA application (7.97 Mg.hm⁻²), both significantly outperforming the control (no N). The most efficient N use was recorded for the single ENSIN application, yielding 27.4 kg of grain per kg of applied N. Agrochemical analyses were conducted to assess soil NH₄⁺ and NO₃⁻ content throughout the vegetation period, and lysimetric methods were used to determine leaching losses. The results highlight the potential of NIs to improve nutrient uptake efficiency, reduce N loss, and enhance sustainable barley production. Through optimizing fertilizer application strategies, this study contributes to the development of more sustainable agricultural practices that improve crop yield while minimizing environmental impacts, particularly in reducing N runoff and groundwater contamination. Full article

Excessive irrigation in protected vegetable production often results in soil nutrient loss and groundwater contamination. Cucumber (Cucumis sativus L.) is a widely cultivated and important vegetable in the world and a sensitive plant to irrigation water supply. In order to obtain higher water use efficiency (WUE) and to assess the leaching loss of mineral elements under the current strategies of irrigation and fertilization in the production of protected crops, we conducted experiments with three irrigation levels, namely, normal (NI), optimized (OI), and deficit irrigation (DI), on cucumber in a solar greenhouse. The results indicated that the contents of nitrate–nitrogen (NO₃⁻–N) in the top soil layer increased significantly under the reduced irrigation condition (OI and DI) after two cultivation seasons compared with normal irrigation (NI). However, there were no significant differences in the contents of available phosphorus (A–P) and available potassium (A–K) between the three treatments in each soil layer during a single irrigation cycle and for the whole growth cycle. In addition, compared to the NI condition, reducing the amount of irrigation (OI and DI) decreased the amount of leaching of the soil mineral elements by more than half without jeopardizing the fruit yield of cucumber, particularly for DI. Under the three irrigation treatments, the economic yield of cucumber varied from 64,513 to 72,604 kg·ha⁻¹ in the autumn–winter season and from 89,699 to 106,367 kg·ha⁻¹ in the winter–spring season, but the differences among the treatments were not significant. Moreover, the reduced irrigation treatments (OI and DI) substantially improved WUE by 43.9% and 135.3% in the autumn–winter season, and by 82.2% and 173.7%, respectively, in the winter–spring season, compared to the NI condition. Therefore, deficit or optimized irrigation was a potential and suitable irrigation strategy in the solar greenhouse for increasing the water use efficiency, reducing the amount of leached soil mineral elements, and maintaining the economic yield of cucumber crop. Overall, our results provided some insight into the future applications of water-saving irrigation techniques in sustainable greenhouse vegetable production. Full article