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This paper discusses the development of a glassy carbon electrode (GC) for the determination and electro-remediation of sulfamethazine (SMZ) in natural waters using multi-walled carbon nanotubes (MWCNT) and silver nanoparticles (AgNPs) as electrode modifiers. The SMZ is an antibiotic found in surface and groundwater that can cause impacts for the environment and the population even at low concentrations. Therefore, it is essential to develop innovative approaches for the SMZ determination and degradation. The proposed GC electrode modifier was characterized demonstrating that the silver nanoparticles was incorporated onto the MWCNT. Voltammetric parameters of the SMZ oxidation process were optimized to improve the response in the analysis. The linearity obtained was from 0.3 to 5.0 µmol L−1, and the limit of detection and limit of quantification obtained was 0.19 µmol L−1 and 0.63 µmol L−1, respectively. This electrode was used for SMZ quantification in natural waters and interferents were used in a selectivity study. Finally, the GC/MWCNT-AgNPs was applied for the remediation of SMZ using chronoamperometry with +1.5 V for 2.5 h, decreasing 62.04% of the antibiotic. As a result, MWCNT-AgNPs were found to be an excellent option for the effective determination and remediation of the SMZ. [ABSTRACT FROM AUTHOR]

Most natural granular deposits are spatially variable due to heterogeneities in soil hydraulic conductivity, layer thickness, relative density, and continuity. However, existing simplified liquefaction evaluation procedures treat each susceptible layer as homogeneous and in isolation, neglecting water flow patterns and displacement mechanisms that result from interactions among soil layers, the groundwater table, foundation, and structure. In this paper, three-dimensional, fully coupled, nonlinear, dynamic finite-element analyses, validated with centrifuge experimental results, are used to evaluate the influence of stratigraphic layering, depth to the groundwater table, and foundation-structure properties on system performance. The ejecta potential index (EPI) serves as a proxy for surface ejecta severity within each soil profile. The results reveal that among all the engineering demand parameters (EDPs) and geotechnical liquefaction indices considered, only EPI predicted a substantial change in the surface manifestation of liquefaction due to changes in the location of the groundwater table and soil stratigraphy. This trend better follows the patterns from case history observations, indicating the value of EPI. Profiles with multiple critical liquefiable layers at greater depths resulted in base isolation and reduced permanent foundation settlement. Ground motion characteristics have the highest influence on EDPs, among the properties considered. The outcropping rock motion intensity measures with the best combination of efficiency, sufficiency, and predictability were identified as cumulative absolute velocity (for predicting foundation's permanent settlement and free-field EPI) and peak ground velocity (for peak excess porepressure ratio). These results underscore the importance of careful field characterization of stratigraphic layering in relation to the foundation and structural properties to evaluate the potential liquefaction deformation and damage mechanisms. The results also indicate that incorporating EPI alongside traditional EDPs shows promise. [ABSTRACT FROM AUTHOR]

Water inrush is one of the most frequent and harmful geological hazards during tunnel construction, especially in deep-buried and long tunnels. Given the complexity and uncertainty of the geological conditions along the deep-buried and long tunnels, a small-scale mathematical interval is used to quantify the evaluation indices rather than a certain value, and an attribute interval assessment method for tunnel water inrush is proposed. Firstly, considering the hazard-pregnant and hazard-causing factors of water inrush occurrence, the formation lithology, unfavorable geology, groundwater level, topography and geomorphology, attitude of rock formation, contact zone of dissolvable and insoluble rocks, and layer and interlayer fissures are selected as the evaluation indices. Then, the single-index attribute measure functions are constructed to calculate the upper and lower limits of each evaluation index belonging to the four risk levels. The fusion function of multi-index attribute measure intervals is established, and the most probable risk level is identified. Meanwhile, a new comprehensive weighting method for risk assessment of tunnel water inrush is presented by combining the frequency statistics method and triangular fuzzy number theory-analytic hierarchy process (TFN-AHP). Finally, the proposed method is applied to the Yunwushan Tunnel. The evaluation results agree well with the actual situation, which verifies the practicality and feasibility of this method and provides a basis for the risk control of geological hazards in tunnel engineering. [ABSTRACT FROM AUTHOR]

Studies that do not separate the adsorption of toxic elements and compounds by outer and inner spheres can lose precision regarding the potential pollution of the water table. We sought to establish details of inner sphere adsorption (ISA) mechanisms of arsenate (H2AsO4−) and lead (Pb2+) on synthetic goethite under different experimental conditions: pH 5.0 and 9.0; purified and unpurified samples; different contact times (24 and 240 hours). Goethite (Gt) was saturated separately with Pb and arsenate (noncompetitive adsorption) and the outer sphere forms was previously removed. The ISA of Pb (maximum of 67,682 mg kg−1) was more intense than that of As (maximum of 4,492 mg kg−1). ISA of arsenate on goethite was dependent on the contact time and was more intense in acidic soils due to the greater possibility of the occurrence of biprotonated ferrol groups (Fe-OH2+0.5) on goethite surface. The high negative charge density at the surface of the H2AsO4− tetrahedron favored its ISA. On the other hand, the lower the level of ISA, the greater binding energy on goethite or adsorption stability of H2AsO4−. The highest ISA of Pb occurred at the highest pH, when the hydroxylated species PbOH+ preferentially binds to oxygen from the deprotonated ferrol group (Fe-O−1.5), without the need for ligand exchange. The proposal mechanisms of inner sphere adsorption allow better understanding of the recovery actions of contaminated soils rich in Fe and Al oxides. [ABSTRACT FROM AUTHOR]

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Slope deformation is an important indicator for landslide warning. Due to the influence of internal and external factors, slope deformation of deep excavated expansive soil canals exhibits significant spatiotemporal heterogeneity. In this study, a comprehensive method for analyzing the spatiotemporal characteristics of deformation and determining potential sliding surfaces was developed. The soft dynamic time warping algorithm was used to measure the similarity of slope displacements at different depths. The hierarchical clustering method was applied to cluster measuring points, thus distinguishing the similarity and heterogeneity of displacements of measuring points. The weighted multiscale local outlier factor algorithm was employed to identify measuring points with sudden displacement changes in order to determine the potential sliding surface. A case study was conducted on a deep excavated expansive soil canal slope in the middle route of the South to North Water Diversion Project in China. The slope experienced significant deformation and had exceeded the allowable deformation value after 3 years of operation. Both the fluctuation depth of the groundwater level and the deformation depth exceeded 10 m. All of the clustering numbers of the measuring points of the inclinometer tubes were 3, but the depths of Cluster 1 were different. The potential sliding surface was a polyline, with a depth of greater than 10 m. It can be concluded that the potential failure mode is a deep landslide. The studied case demonstrates the effectiveness and reliability of the proposed method, which can provide a reference for operation management of similar projects. [ABSTRACT FROM AUTHOR]

AbstractPica is one of the most lethal self-injurious topographies. Despite this, more research is needed on teaching comprehensive adaptive skills to replace pica in varying contexts, particularly outside of specialised hospital admissions in the United States. Pica may include items such as sand, lotion, non-potable water, and clothing. Culturally, most Australians live near the coast. Australia has the highest skin cancer rates in the world, and for children enforces substantial mandatory sun protection and water safety measures (e.g., rash guard “rashie” tops, sun hats with school uniforms, sunblock, Surf Life Saving training). We present a case history of an 8.5-year-old male with pica and food stealing. He engaged in pica with his rashie, sun hats, and sunblock, and consumed substantial volumes of sand, sea water, seaweed, and chlorine swimming pool water. Behaviour-analytic assessment and treatment using single-case experimental designs occurred in the family home. Pica was high in the absence of social environmental consequences, and no stimuli competed. Response interruption and redirection with differential reinforcement was effective in increasing independence in multiple contexts with 7 skills such as discarding, putting away, and engaging with some materials appropriately (apply sunblock, put and keep sun hats on, play with beach toys and a sand and water play table), and refraining from touching other items (e.g., mud puddle, other’s food). Toy engagement increased and pica decreased. He met 100% of goals and learned to drink potable water and eat appropriately from crockery on a table. Parents were trained and reported high social validity, and gains maintained. [ABSTRACT FROM AUTHOR]

Abstract\nNOVELTY STATEMENTThe study presents the implementation of a constructed wetland system utilizing vetiver (Chrysopogon zizanioides) and jute (Corchorus olitorius) for attenuating aqueous naphthalene and carbendazim. The removal efficiencies for naphthalene were 90.25%, 78.27%, 82.97%, 85.11%, and 92.38%. Similarly, for carbendazim, they were 91.84%, 70.06%, 81.46%, 79.41%, and 80.45% in batch studies for raw and dried vetiver leaves, roots, and jute. The maximum sorption capacity ranged between 0.3825 and 2.2227 mg/g. A change in pH in the range of 2–10 resulted in decreased carbendazim sorption (maximum of 80% at pH = 2; minimum of 16% at pH = 10), while negligible change was observed for naphthalene. Temperature elevation from 5 to 45 °C led to enhanced removal efficiency for both naphthalene (23% at 5 °C to 95% at 45 °C) and carbendazim (16% at 5 °C to 93% at 45 °C) across all sorbents. In wetlands with only vetiver, average removal efficiencies over a 9-day experiment were 89.71% and 83.05% for naphthalene and carbendazim, respectively. Incorporating jute further improved the removal efficiencies to 96% and 94.8%, respectively, over 30 days. The outcome proves that constructed wetlands with vetiver, and jute might efficiently attenuate hazardous contaminants like naphthalene and carbendazim in wastewater, which is significant from a social health perspective.The novelty of this study is in the selection of Chrysopogon zizanioides (vetiver) and Corchorus olitorius (jute) together, which have effectively removed naphthalene and carbendazim from wastewater. Although this technique has only been laboratory tested, further field experiments incorporating natural factors are necessary. However, some promising results obtained with vetiver and jute in efficiently attenuating both contaminants from aqueous solutions suggest that this approach could be applicable in field-scale engineered wetland arrangements. The key benefit of this system is its simplistic nature and low maintenance requirements, making it accessible to industries, rural communities, and government organizations. Its affordability and effectiveness make it an attractive option for removing persistent organic compounds from wastewater, thus preventing their entry into surface and groundwater bodies. [ABSTRACT FROM AUTHOR]

Since the 21st century, large-scale afforestation projects on the Loess Plateau have resulted in significant vegetation greening, contributing to ecosystem restoration and enhanced soil conservation. However, these efforts have also led to soil aridification, declining groundwater levels, and reduced terrestrial water storage. These negative consequences are primarily attributed to increases in evapotranspiration (ET), which has augmented water consumption. Despite these findings, the underlying mechanisms driving ET variations remain contentious due to the complex interplay of multiple factors. In this study, we employed a logical attribution method, which attributes vegetation changes predominantly to anthropogenic activities (e.g., reforestation or land-use changes), while directly linking changes in climatic factors (e.g., temperature and precipitation) to climate change. We separately examined the contributions of long-term trends and interannual variability in ET to reveal distinct driving forces. Between 2000 and 2022, approximately 80% of areas showing significant changes in ET and its components were directly influenced by vegetation greening, particularly in the central part of the Loess Plateau, where restoration efforts were most prominent. In contrast, only around 20% of these changes were attributable to climate change and other factors. After removing long-term trends, interannual variations in ET were found to be more closely associated with climatic factors (temperature and precipitation), especially in arid and semi-arid regions. This indicates that climate is the dominant factor driving interannual variations in ET across the Loess Plateau. Our findings contribute to a deeper understanding of the water cycle dynamics in the context of large-scale vegetation restoration on the Loess Plateau. These insights provide a scientific foundation for policymakers to evaluate the environmental impacts and potential water-related risks associated with ecological restoration projects. [ABSTRACT FROM AUTHOR]

The behaviour of water between the surface and subsurface is a dynamic and intricate process, involving a complex interplay between surface water and groundwater. This interaction is vital for supporting ecosystems, providing water supplies, and ensuring the sustainable use of water resources. Disruptions in these interactions, such as over-extraction, reduced streamflow, and the impacts of climate change, contribute to water scarcity. An integrated management of surface and groundwater resources is crucial for addressing these challenges and ensuring the long-term availability and sustainability of water supplies. In this study, the spatiotemporal variations of surface and groundwater interactions were analysed using integrated SWAT and MODFLOW model using QSWATMOD plugin in QGIS software. The surface and groundwater interactions were analysed for future periods under climate and land use land cover (LULC) change scenarios. Pre-monsoon, monsoon, post-monsoon kharif, and post-monsoon rabi seasons are considered for analysing the surface and groundwater interactions. The future LULCs are projected using the DynaCLUE model for three user-defined scenarios such as past trend (scenario 1), drastic change in built-up and barren land (scenario 2), and restricted agricultural land (scenario 3). For projecting the interactions under both changing climate and LULC, LULC scenario 1 was used for near-future period, LULC scenario 2 for mid-future period, and LULC scenario 3 for far future period. Under the climate change scenario, the maximum groundwater recharge under SSP5-8.5 scenario is observed to be 20,805 m3/day in the near future, and the maximum discharge under SSP2-4.5 scenario is observed as 9,035 m3/day in the mid-future period. In both climate change and combined scenarios (both climate and user-defined LULC), there was a greater recharge of groundwater during the monsoon season relative to other seasons, while there was a greater discharge of groundwater during the post-monsoon rabi season. In the combined scenarios, the maximum discharge was under SSP5-8.5 with 15,009 m3/day in the mid-future, and the groundwater recharge was greater in the near future period under SSP3-7.0 with 19,556 m3/day. The groundwater–surface water interactions were analysed in four seasons, out of which monsoon season had the maximum recharge and groundwater discharge was more in the post-monsoon rabi season. The results found in this study' can be used to plan and develop short-and long-term integrated surface and groundwater management strategies of the basin under changing climate and LULC. [ABSTRACT FROM AUTHOR]

Groundwater restoration is increasingly common to mitigate groundwater overexploitation, which proves effective in resolving urban water scarcity and regional unsustainable development. China's South-to-North Water Diversion Project is one of the largest water transfer projects to restore groundwater and resolve water shortage in Beijing. However, how the rapidly restored groundwater of this magnitude changes regional seismic stability is largely unknown. Here, we explore the relation between elevated groundwater table and seismic ground liquefaction based on the case of Beijing under the impact of the South-to-North Water Diversion Project. We collect groundwater table depth records and use them to drive three-dimensional geotechnical models that generate ground liquefaction hazard maps. We find a remarkable increase in coverage and severity of liquefaction due to groundwater table rise. Infrastructures built during the rapid urbanization process are often under low groundwater table and thus illy prepared for this increased seismic risk. These findings highlight the necessity to consider the seismic consequence of large-scale groundwater restoration projects. The authors find that groundwater table recovery leads to a remarkable increase in seismic liquefaction risk in Beijing. The findings highlight the necessity to consider the influence of rapid groundwater restoration on seismic safety in megacities. [ABSTRACT FROM AUTHOR]

Exfiltration from sanitary sewers has been researched for many years because of its potential impact on shallow groundwater or surface water, but measurements of exfiltration in situ are rare. Most previous measurements of sanitary sewer exfiltration have been done in the laboratory, in the field using natural, chemical or pharmaceutical tracers or modeled. Relatively few studies have employed physical measurements of volume loss in field settings. Here, we design, test, and apply at a watershed scale, a new methodology for measuring volume loss from sanitary sewer pipes that are currently in use and under typical operating conditions (i.e., not pressurized). The measurement system works by: (1) isolating a section of sanitary sewer between maintenance holes using a sewer bypass or equivalent, (2) introducing roughly 4,200 L of water at a controlled rate into the upstream inspection hole so that pipes remain one-third to one-half full, (3) using vacuum pumps to recover the introduced water at the downstream inspection hole, then (4) measuring differences in the volume from what was pumped into the inspection hole to what was recovered. This process is repeated up to six times to achieve a sensitivity of 0.95 L per experimental pipe segment. This technique was applied to 23 pipe segments of various ages and materials of construction that were selected to be a representative sample of the pipes throughout San Diego. Collectively, these pipes averaged averaged 3.78 × 10−2 L/s-km exfiltration rates (95%CI: 4.96 × 10−2, 2.60 × 10−2). Two of the pipe segments were infiltrating groundwater. Six pipe segments were not statistically different from zero (i.e., no exfiltration). There was no statistical difference between pipe segments of differing ages (p = 0.5) or materials of construction (p = 0.3). This study represents an initial effort at measuring exfiltration from in situ sanitary pipes. Future applications of this methodology should focus on method optimization, measurements at additional locations, and expanding measurements to collect data from additional types of pipe to better understand the geographic portability of the method and the relationship between exfiltration rates, pipe material, and pipe age. [ABSTRACT FROM AUTHOR]

This study has checked 222Rn concentrations in groundwater from 27 sites of Haridwar and Dehradun, Uttarakhand, using the Durridge RAD-7. Seasonal variability reveals that the activity of radon is at its peak during the monsoon. Among the samples, 96.29% exceeded the United States Environmental Protection Agency's Maximum Contaminant Level for radon during monsoon. The results indicated significant correlations between the concentration of radon and some factors like electrical conductivity and pH. The objective is to compare seasonal radon levels in groundwater, identify significant variations, and assess potential health risks by evaluating them against established safety guidelines. [ABSTRACT FROM AUTHOR]

Rapid recharge to the water table at groundwater monitoring locations across the Delaware River Basin (DRB), USA is examined using a data-driven mechanistic infiltration model. Daily water-table altitude is used to estimate diffuse and rapid recharge in response to daily precipitation, snowmelt, and evapotranspiration. The model is defined from balance equations, where instead of soil-moisture retention functions defining unsaturated-zone fluxes, fluxes are defined using parameters analogous to the water-residence time in the unsaturated zone. Unsaturated-zone balance equations are coupled at the water table, combining recharge at the water table, the time-varying water-table altitude, and fluxes in the saturated flow regime. The model is applied over a 17-year period at 32 US Geological Survey Climate Response Network wells completed in the unconsolidated Coastal Plain aquifer and fractured-rock aquifers across the DRB. Daily estimates of diffuse and rapid recharge are aggregated over seasons and seasonal characteristics of the frequency and magnitude of rapid recharge are compared across different geologic settings. The fraction of the average seasonally aggregated recharge attributed to rapid recharge (Φr-rech) at monitoring locations is largely explained by the depth to the water table (DTW) and the geologic setting, which is defined from the geologic age and lithology. Distinctive characteristics of the void space within different geologic settings are hypothesized to influence the occurrence of rapid recharge. Φr-rech decreases with increasing DTW, and in geologic settings characterized by fractured Paleozoic and Precambrian bedrock, Φr-rech tends to be greater than that in unconsolidated aquifers for locations having a similar DTW. [ABSTRACT FROM AUTHOR]

This article presents a method that allows for the assessment and classification of the suitability of urban areas for the installation of infiltration basins and trenches to improve rainwater drainage. The proposed method utilizes commonly available archival data regarding soil lithology and permeability, vadose zone characteristics, and aquifer depth. The algorithm considers the aforementioned factors along with the characteristics of the study area to determine rainwater infiltration potential. The developed model, named DIS, incorporates the key factors: depth of water table (D), impact of vadose zone (I) and soil media (S). On the basis of the DIS index values, five assessments of terrain suitability for rainwater management were proposed. It is suggested that a DIS index value below 1 indicates no possibility of water draining into the ground, whereas DIS index values above 2.5 suggest optimal conditions for the construction of infiltration basins and trenches. The algorithm was further applied to analyze the spatial variation of the DIS index across an urban area employing geostatistical methods and GIS techniques. The DIS method can be applied to rainwater management at both local and regional scales to support urban planners and developers in decision making processes. [ABSTRACT FROM AUTHOR]

Karst aquifers are particularly vulnerable to tunnel excavation; however, studies on tunnels in karst environments remain limited, and none have explored the depth and pathways of karst groundwater circulation resulting from tunnel excavation using hydrogeochemical evaluation. This study analyzed hydrogeochemical variations in precipitation, groundwater and tunnel drainage in a karst trough valley in Chongqing, Southwest China, comparing these changes to groundwater levels and discharges. Following tunnel excavation, ion concentrations derived from human activities in epikarst springs decreased, while ion concentrations from natural karst processes increased. At the drainage zone near the exit of the adjacent railway tunnel, the increase in ion concentrations from human activities was greater than the changes in other ions, while ions from karst processes showed a decrease. The evaluation of groundwater discharge and hydrogeochemical changes indicated that tunnel excavation altered the pathways and depths of groundwater circulation. Newly formed fissures generated from the tunnel excavation provided additional runoff pathways for downward movement of upper soil water and epikarst water, resulting in variations in groundwater mixing and changes in hydrogeochemical characteristics. This study provides evidence and a practical approach for investigating groundwater circulation in karst trough valleys. [ABSTRACT FROM AUTHOR]

The hydrological model, DRAINMOD-NII, has undergone modifications to simulate automatic controlled drainage (ACD) and automatic controlled drainage/subirrigation (ACD-SI) systems based on simulated field water table depths (WTD). The model assesses the predicted daily WTD to ensure it falls within a predefined desired range. The lower limit of this range is set at three times the maximum root depth during the growing season, while the upper limit is 30 cm below the soil surface. The modified model automates the ACD-SI system by eliminating the control structure (weir) entirely when the WTD is shallower than the upper limit. Conversely, it switches to subirrigation mode when the water table is deeper than the lower limit. The model was applied to two US data sets from North Carolina and Illinois, simulating five drainage management systems: Conventional Drainage (CVD), Traditional Controlled Drainage (TCD), Subirrigation, ACD, and ACD-SI. The results demonstrated that the predicted drainage, nitrogen losses, and crop yield are similar for the TCD and ACD systems. However, the ACD-SI system showed lesser simulated drainage and nitrogen losses and greater crop yield when compared to the other systems. The ranges of reductions in drainage losses compared to the CVD system were increased from 25%–41% to 27%–45% for the TCD and ACD systems to 36%–51% and 47%–62% for the ACD-SI system for the NC and IL data sets, respectively. Also, the ranges of reductions in nitrogen losses were increased from 6%–57% to 21%–35% for the TCD and ACD systems to 21%–69% and 36%–52% for the ACD-SI system for the NC and IL data sets, respectively. Furthermore, the ACD-SI system had an economic impact as it increased relative crop yield and reduced the amount of water required for subirrigation compared to the traditional subirrigation system. [ABSTRACT FROM AUTHOR]

The 2021–2024 Nordic Waste Landslide, located near the village of Ølst in East Jutland, Denmark, was a significant geohazard event, occurring within a former clay pit that had been repurposed as a landfill for polluted soil. This study provides a first analysis of the landslide's development, characteristics, and causative factors. The slow-to-moderate-moving landslide gained public attention in December 2023 when it protruded beyond the landfill area, threatening to reach Ølst and dispense pollutants to large downstream watercourses. We analyzed the landslide's evolution and causative factors utilizing aerial imagery, digital elevation models (DEMs), satellite data, and field observation. The landslide's evolution can be categorized into two distinct phases driven by two modes of soil deposition. In Phase 1, spanning 2021 to spring 2023, the landslide developed due to gradual vertical soil aggradation on the gently sloping surface of the former clay pit. In Phase 2, from spring 2023 to January 2024, the landslide developed rapidly due to substantial soil dumping on the western slope of the clay pit, forming two earthflows that moved east, forcing acceleration in most of the Phase 1 landslide. The Phase 2 landslide encompassed approximately 1.2 million cubic meters of soil, accounting for over half of the total soil deposited at Nordic Waste between 2015 and 2023. After the practice of dumping soil at the edge of the clay pit ended the landslide slowed down, eventually stopping by late January 2024. This was while the water table was at a record high and still increasing, pointing to soil deposition, and not elevated water table, as the main preconditioning factor. Runout modelling indicated the landslide was best replicated using a Voellmy friction angle of atan(μ) = 2.9°. However, even in a worst-case modelling scenario, assuming an unrealistically low atan(μ) of 1.7°, the landslide did not reach inhabited areas in Ølst. From a landslide point of view, our findings emphasize the need for land-use planning and regulatory frameworks of landfills to take slope instability into account. Furthermore, they highlight the need for increased public awareness, and for educating decision-makers and oversight authorities into the risks associated with landslides. [ABSTRACT FROM AUTHOR]

This study utilizes three models, namely Weight of Evidence (WOE), Frequency Ratio (FR), and Index of Vulnerability (IV), to identify groundwater potential zones (GWPZ) in southern Khyber Pakhtunkhwa, Nowshera District, Pakistan. We incorporated a total of twelve variables, encompassing elevation, slope, distance to the rivers, rainfall, curvature, drainage density, land use/land cover, topographic wetness index, height above the nearest drainage, NDVI, distance to the roads, and soil type, utilizing ArcGIS 10.8. The AUROC (Area Under the Receiver Operating Characteristic) assessed the dependability of the models. GWPZ was categorized into five classifications: very low, low, moderate, high, and very high. The WOE model produced distributions of 10.14 % (262.09 km2), 19.58 % (506.00 km2), 26.75 % (691.10 km2), 27.10 % (700.18 km2), and 16.40 % (423.75 km2) respectively. The FR yielded 20.93 % (538.90 km2), 32.38 % (833.53 km2), 18.92 % (487.14 km2), 13.13 % (337.94 km2), and 14.61 % (376.07 km2). The IV model resulted in 14.41 % (372.46 km2), 17.17 % (443.67 km2), 29.01 % (749.52 km2), 25.85 % (667.97 km2), and 13.53 % (349.50 km2). The AUC-ROC for WOE, FR, and IV were 58.06%, 87.53%, and 84.98%, respectively. All models accurately defined the GWPZ, with the FR approach demonstrating notable potential. These findings provide vital information for managing groundwater resources and the design of metropolitan areas. Our developed methodology can be used in places with comparable characteristics. It is a valuable tool for policymakers interested in sustainable groundwater management. [ABSTRACT FROM AUTHOR]

The Gravity Recovery and Climate Experiment (GRACE) introduces a new approach to accurately monitor, in real time, regional groundwater resources, which compensates for the limitations of traditional hydrological observations in terms of spatiotemporal resolution. Currently, observations of groundwater storage changes in Jiangsu Province face issues such as low spatial resolution, limited applicability of the downscaling models, and insufficient water resource observation data. This study based on GRACE employs Random Forest Regression (RFR) and Geographically Weighted Regression (GWR) methods in order to obtain high-resolution information on groundwater storage change. The results indicate that among the established 66 × 158 local GWR models, the coefficient of determination (R2) ranges from 0.39 to 0.88, with a root mean squared error (RMSE) of approximately 2.60 cm. The proportion of downscaling models with an R2 below 0.5 was 18.52%. Similarly, the RFR models trained on the above time series grid data achieved an R2 of 0.50, with the RMSE fluctuating around 1.59 cm. In the results validation, the monthly correlation coefficients between the GWR downscaling results and the data of measured stations ranged from 0.37 to 0.66, with 53.33% of the stations having a coefficient greater than 0.5. The seasonal correlation coefficients ranged from 0.41 to 0.62, with 60% of the stations exceeding 0.5. The correlation coefficients for the RFR downscaling results ranged from 0.44 to 0.88, with seasonal correlation coefficients ranging from 0.49 to 0.84. Only one station had a correlation coefficient below 0.5 for both monthly and seasonal results. In the validation of the correlation accuracy between the downscaling results and the measured groundwater levels, the Random Forest model demonstrated better predictive performance, which offers distinct advantages in improving the spatial resolution of groundwater storage changes in Jiangsu Province. [ABSTRACT FROM AUTHOR]

Hydraulic permeability and water content are usually measured on-site in wells or laboratory tests and are commonly supplemented with geohydrological inferences from geoelectrical data. Current approaches take advantage of the similarities between the physical processes behind electrical and hydraulic flows and the water distribution in a fully or partially saturated medium, leaving aside the complete transition from saturated to unsaturated media commonly observed in geoelectrical exploration. We hypothesize that the natural spatiotemporal variations in water content influence both electrical and hydraulic data in partially saturated media, and in turn, the hydraulic pressure-driven saturation can be used to unify and increase the sensitivity of both data types to hydraulic permeability. This paper introduces a theoretical framework for integrated hydraulic and electrical data modeling coupled with a pressure-dependent effective saturation curve. Following the adjoint state formalism, we develop the expression of the coupled sensitivity of electrical and hydraulic data to hydraulic permeability. We tested this methodology on three synthetic scenarios of unconfined aquifers to determine how the electrical data can increase the sensitivity of piezometer data to hydraulic permeability in a homogeneous and heterogeneous medium. From these experiments, we found that the electrical data are particularly sensitive to hydraulic permeability in the vadose zone, thus overcoming the lack of sensitivity of typical piezometer data for this zone. We also found that this sensitivity is maximum in the immediacies of the water table, which acts as a natural permeability scanner when accumulated measurements for different hydric stresses are made over time. [ABSTRACT FROM AUTHOR]

Water is a valuable natural resource, indispensable in the productive, economic, and social development of human beings, agriculture, and domestic and industrial uses throughout the world. Two samplings were established to evaluate the quality of surface and underground water for agricultural irrigation in the Sierra de Amula Region, Jalisco, Mexico. The first was performed during the dry season from November 2021 to April 2022, and the second was performed during the rainy season from July to September 2022 through completely random probabilistic sampling and a longitudinal descriptive study. In total, 25 surface water and 30 groundwater samples were taken. Each sample was evaluated for its pH, electrical conductivity, and ionic concentration (Ca2+, Mg2+, Na+, K+, CO32−, HCO3−, CI−, SO42−). For data analysis, we determined the ionic concentrations and the salinity and sodicity indexes, including the electrical conductivity, pH, sodium adsorption ratio (SAR), and cationic ratio of soil structural stability (CROSS). The results indicate that the ionic concentration is mainly due to calcium bicarbonate, probably due to the geology of the region through water–rock interactions, and the pH is between 6.64 and 7.77; with respect to EC, most of the sampled sites are concentrated in medium-salinity waters of 250–750 µS cm−1. The sodium adsorption ratio (SAR) showed that the waters have high ionic concentrations of calcium and magnesium and low sodium. The CROSS values were lower than the SAR values, showing that the concentration of potassium ions K+ is low in the evaluated waters. With respect to salinity and sodicity, the water quality of the sampled sites, both surface and groundwater, can be considered good for agricultural use. Given that it was sampled in two seasons, the concentration of ions varies in the rainy season, with the dragging of materials causing the ions to concentrate to a greater extent. This type of research benefits farmers in reducing production costs, having knowledge of water quality, and decision making. We recommend that the alkaline pH of the surface or groundwater be conditioned according to the requirements of the crop to be grown and the irrigation method to be used. [ABSTRACT FROM AUTHOR]

Many excavations and tunnels experience problems and instability caused by uncontrolled groundwater inflows or groundwater pressures that influence stability and soil behaviour. A range of groundwater control measures can be used to overcome these problems and create stable and workably dry conditions below groundwater level. A key challenge for designers is that the performance of the various different techniques is strongly influenced by the hydrogeological conditions at a site. Furthermore, the available ground investigation data may have data gaps or considerable uncertainty regarding key parameters such as hydraulic conductivity or hydraulic boundary conditions. This means that, when working with real-world datasets, there are some groundwater problems where analysis involves so many assumptions and uncertainties that the design outcomes are of little practical value. This paper will discuss how thinking conceptually about groundwater problems can be of great benefit when developing groundwater control schemes, and propose that a robust conceptual model helps reduce the risk of designs being developed using inappropriate techniques. Historic examples from the nineteenth century and early twentieth century (before sophisticated methods of groundwater analysis were available) are described, where developing a conceptual understanding of groundwater conditions was vital in developing practical engineering solutions. [ABSTRACT FROM AUTHOR]

Specific yield (Sy) is an essential hydrogeological parameter in groundwater-related modeling and estimation. In this study, we proposed several new analytical expressions of Sy to characterize the nonlinear variations of Sy under shallow groundwater environments, encompassing Sy for three-layered soil, transition zone Sy, and flux-dependent Sy (in Boussinesq-type equation). The proposed Sy expression for three-layered soils expanded the applicability of previous expressions for homogeneous soil. The result indicated that different from the trend for homogeneous soil, Sy for three-layered soils may also decrease with the increase of water table depth. Besides, Sy corresponding to the transition zone (Sy,tz) was analytically quantized to improve the previous empirical method, and we found that Sy,tz was not dependent on initial water table depth but the increment of depth. Moreover, flux-dependent Sy in the Boussinesq-type equation was proposed by considering the vertical fluxes in the unsaturated zone, which effectively improved the modeling behavior of the previous Boussinesq-type equation with Sy under the hydrostatic assumption. Sensitivity analysis of analytical expressions showed that saturated moisture content, shape parameter α, and water table depth were the three most important variables for Sy expressions. Overall, our study expanded the applicability of the previous analytical expressions of Sy and offered valuable analytical approaches for sustainable groundwater management. [ABSTRACT FROM AUTHOR]

This study investigated the occurrence, concentration and human health risks of five pharmaceutical residues—metronidazole, sulfamethoxazole, ciprofloxacin, carbamazepine, and caffeine—in groundwater and surface water samples from Kampala and Mbarara districts of Uganda. The present study also employed techniques of remote sensing and geographic information system (GIS); thereby, emphasizing the importance of thematic mapping, land use classification, and spatial buffering to evaluate pharmaceutical contaminants in an environmental setting. The risk quotient (RQ) approach was also employed to assess the risk of exposure to the pharmaceutical contaminants. Caffeine was found with the highest average concentration in groundwater (53.515 µg/L), whereas carbamazepine had the highest average concentration in surface water (48.635 µg/L) during the dry season. Ciprofloxacin consistently recorded the lowest average concentrations in both groundwater and surface water across all seasons. Overall, the data revealed high concentrations of pharmaceutical residues in surface water compared to groundwater during both seasons, except for caffeine which was not detected in surface water across the seasons. Notable seasonal changes were also observed in caffeine and metronidazole concentrations, indicating the role of human activities and environmental factors in influencing contamination patterns during specific seasons. The factor analysis revealed that consumption rate of pharmaceuticals and anthropogenic activities are the main factors responsible for the contamination of groundwater and surface water. Moreover, results revealed that the risk of adverse human health effects for carbamazepine and metronidazole during both seasons were high (RQ > 1), thereby highlighting the prioritization of frequent monitoring by the environmental protection agencies. Given that the combined risk of exposure for all the pharmaceuticals exceeded one, adopting stringent pharmaceutical disposal and control measures are essential for mitigating potential human health risks associated with their exposure. Further investigation into optimal and effective pharmaceutical remediation strategies for both groundwater and surface water are highly recommended. [ABSTRACT FROM AUTHOR]

In this study, we present a data-driven approach, referred to as gray box modeling, that aims to achieve a balance between the transparency of white box models and the predictive power of black box models in groundwater level prediction. We conceptualized the groundwater system as a series of three interconnected tanks representing the surface, the unsaturated zone, and the saturated zone (aquifer). Each tank accounted for various hydrological processes, including rainfall, infiltration, interflow, recharge, groundwater discharge, and pumping. A signal processing approach called average magnitude of pumping (AMP) was used to evaluate the pumping rate. The methodology involved data collection and preparation, curve fitting using the least-squares method, and performance evaluation metrics such as root-mean-square error (RMSE), mean absolute error (MAE), and R2. The gray box model was validated by a training and testing process to ensure its accuracy. Then, the gray box model was applied on the entire data set to predict the groundwater level of three observation stations located in the Chou-Shui Chi alluvial fan. The groundwater budget results indicated higher rainfall recharge for the stations located in the top fan compared to the station in the middle fan, highlighting the impact of geological factors on groundwater recharge and response to rainfall. Furthermore, the results revealed a negative balance in the groundwater budget at one station; this can be attributed to a significant increase in pumping intensity, emphasizing the importance of understanding the relative contributions of various fluxes to groundwater level variations. Last, the gray box approach introduced in this study demonstrated applicability across diverse hydrogeological settings at large basin scales, especially in situations with data limitations for complex physically based models. The method is a valuable and efficient tool for sustainable management of extensive aquifer systems. [ABSTRACT FROM AUTHOR]

State-of-the-art hydrogeological investigations use transient calibrated numerical flow and transport models for multiple scenario analyses. However, the transient calibration of numerical flow and transport models still requires consistent long-term groundwater time series, which are often not available or contain data gaps, thus reducing the robustness and confidence of the numerical model. This study presents a data-driven approach for the reconstruction and prediction of gaps in a discontinuous groundwater level time series at a monitoring station in the Allertal (Saxony-Anhalt, Germany). Deep Learning and classical machine learning (ML) approaches (artificial neural networks (TensorFlow, PyTorch), the ensemble method (Random Forest), boosting method (eXtreme gradient boosting (XGBoost)), and Multiple Linear Regression) are used. Precipitation and groundwater level time series from two neighboring monitoring stations serve as input data for the prediction and reconstruction. A comparative analysis shows that the input data from one measuring station enable the reconstruction and prediction of the missing groundwater levels with good to satisfactory accuracy. Due to a higher correlation between this station and the station to be predicted, its input data lead to better adapted models than those of the second station. If the time series of the second station are used as model inputs, the results show slightly lower correlations for training, testing and, prediction. All machine learning models show a similar qualitative behavior with lower fluctuations during the hydrological summer months. The successfully reconstructed and predicted time series can be used for transient calibration of numerical flow and transport models in the Allertal (e.g., for the overlying rocks of the Morsleben Nuclear Waste Repository). This could lead to greater acceptance, reliability, and confidence in further numerical studies, potentially addressing the influence of the overburden acting as a barrier to radioactive substances. [ABSTRACT FROM AUTHOR]

Responding to a growing concern about impacts from anthropogenic activity on several dozen lakes, a group of citizens initiated and led a water quality sampling program that included characterizing groundwater dependence. The small lakes are located on hummocky glacial terrain near Edmonton, Alberta, Canada. A team of volunteers collected lake samples for a variety of limnological and ecological analyses to document lake health and trophic state, and collaborated with a university research group to identify groundwater dependence using specific environmental tracers (δ2H, δ18O, and 222Rn). Water chemistry and isotopic measurements are largely explained by the position of a lake within the local groundwater flow system. A simple metric to express the likelihood of groundwater dependence was calculated using the total dissolved solids (TDS), δ18O, and 222Rn values. Across the relatively small study area, a greater likelihood of groundwater dependence was determined for lakes located downgradient from an elevated recharge area. In contrast, where the water table was relatively flat, a lower likelihood of groundwater dependence was found. These results were similar to the spatial pattern of a trophic state, indicating that groundwater dependence may be one of the factors responsible for lake ecological status. The data generated by citizens and the knowledge gained about the hydrology of this area will help discussions between landowners and decision makers on how to best manage land use in this diverse landscape. [ABSTRACT FROM AUTHOR]

Excessive use of nitrogen fertilizer in agricultural activities can easily induce nitrogen pollution in groundwater, which may deteriorate groundwater quality. Generally, nitrogen fertilizer passes through the unsaturated zone to groundwater. Therefore, it is of great significance to investigate the migration and transformation of nitrogen pollutants in unsaturated zones for the prevention and control of groundwater nitrogen pollution. Clay-rich soil is often considered a barrier layer to prevent pollutant leakage because of its lower relative permeability, while its prevention capacity is seldom reported under shallow groundwater table conditions. Motivated by this, an in situ experiment and numerical simulation were conducted to investigate the migration and transformation of nitrogen fertilizer in a clay-unsaturated zone with a shallow groundwater table. Systematic measurements and numerical simulation results revealed that nitrogen can pollute groundwater via the infiltration through clay-rich soil in the in situ experiment site. This finding clarified that the difference in hydraulic head under the shallow groundwater table, rather than soil permeability, is the dominant factor in controlling the downward migration of nitrogen pollutants in the clay-unsaturated zone. More importantly, the nitrogen migration is convection dominant during precipitation in this experiment, indicating nitrogen polluted groundwater much faster in humid climate areas. These findings suggest that nitrogen contaminates groundwater easily under shallow groundwater tables in humid climate areas, even with clay-rich soil texture. [ABSTRACT FROM AUTHOR]

The editorial "Advances in Aquifer Systems Analysis" discusses the importance of studying aquifer systems to manage groundwater resources, remediate contamination, and address climate change impacts. The research presented in the special issue covers topics such as groundwater potential mapping, distributed control systems for mineral water wells, hydrodynamic process control, flash flood potential analysis, and groundwater vulnerability mapping. The findings emphasize the significance of numerical modeling and mapping in water resources management and highlight the need for sustainable practices to protect water quality and quantity. [Extracted from the article]

Frequent agricultural irrigation events continuously raise the groundwater table on loess platforms, triggering numerous loess landslides and significantly contributing to soil erosion in the Chinese Loess Plateau. The movement of irrigation water within the surficial loess layer is crucial for comprehending the mechanisms of moisture penetration into thick layers. To investigate the infiltration and evaporation processes of irrigation water, a large undisturbed soil column with a 60 cm inner diameter and 100 cm height was extracted from the surficial loess layer. An irrigation simulation event was executed on the undisturbed soil column and the ponding infiltration and subsequent evaporation processes were systematically monitored. A ruler placed above the soil column recorded the ponding height during irrigation. Moisture probes and tensiometers were installed at five depths to monitor the temporal variations in volumetric water content (VWC) and matric suction. Additionally, an evaporation gauge and an automatic weighing balance measured the potential and actual evaporation. The results revealed that the initially high infiltration rate rapidly decreased to a stable value slightly below the saturated hydraulic conductivity (Ks). A fitted Mezencev model successfully replicated the ponding infiltration process with a high correlation coefficient of 0.995. The monitored VWC of the surficial 15 cm-thick loess approached a saturated state upon the advancing of the wetting front, while the matric suction sharply decreased from an initial high value of 65 kPa to nearly 0 kPa. The monitored evaporation process of the soil column was divided into an initial constant rate stage and a subsequent decreasing rate stage. During the constant rate stage, the actual evaporation closely matched or slightly exceeded the potential evaporation rate. In the decreasing rate stage, the actual evaporation rate fell below the potential evaporation rate. The critical VWC ranged from 26% to 28%, with the corresponding matric suction recovering to approximately 25 kPa as the evaporation process transitioned between stages. The complete evaporation process was effectively modeled using a fitted Rose model with a high correlation coefficient (R2 = 0.971). These findings provide valuable insights into predicting water infiltration and evaporation capacities in loess layers, thereby enhancing the understanding of water movement within thick loess deposits and the processes driving soil erosion. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Groundwater, being an important natural resource, has a dynamic character owing to climate change. The precarious nature of groundwater, especially in the arid and semi-arid regions, demands sustainable management of the same. The present work aims to study the groundwater trend and change point detection with a focus on groundwater drought severity in a semi-arid region of NW India (Rajasthan). Pre-monsoon and post-monsoonal groundwater levels of 65 wells for the period of 2006 to 2018 have been utilised for the various statistical analysis of Mann–Kendall (MK) test, Sen's slope estimator, Buishand U test, depth variation and recharge probability, SGLI and Cluster analysis. Primarily, both the pre- and post-monsoonal groundwater level trend and magnitude have been analysed using the Mann–Kendall test and the magnitude of slope seconded by Sen's slope estimator. A Buishand U test has been performed to detect groundwater level change point detection. A cluster analysis was done to categorise the wells based on their pre-monsoon and post-monsoon groundwater level magnitude trends. According to cluster analysis, the maximum number of stations had a negative trend during the pre-monsoon. Standard The groundwater depth level index has been undertaken for pre- and post-monsoonal drought analysis, and the growth rate formula was used to analyse the depth fluctuation and recharge probability. The result of MK indicated an overall negative trend which is extreme in Sardarshahar tehsil (pre-monsoon) and Rajgarh tehsil (post-monsoon). The results yielded a declining trend in groundwater over the study area. The Buishand U test revealed that about 66.15% and 50.76% of the stations had changed ground water depth during the pre- and post-monsoon period, respectively. Groundwater drought severity has been increasing in both seasons, which is especially extreme during the pre-monsoonal period. The study of depth fluctuation and recharge probability indicated that 46.13% of the stations have excessive use of groundwater while having less groundwater recharge probability. [ABSTRACT FROM AUTHOR]

This study concerns the case of a landslide that occurred at kilometer point PK 208 of the East-West Highway in the northeastern part of Algeria, located in the eastern region of Constantine Province. The primary objective is to understand the behavior and mechanisms of this complex landslide phenomenon. The phenomenon's relationship to various factors that influence this activity, including permanent causes, such as challenging terrain, the geological nature, and the evolving characteristics of the soil under the influence of various climatic conditions or human activities, was investigated. The study examined the impact of the East-West Highway construction at PK 208 on the stability of slopes composed of clayey and marly soils. Field investigations were conducted, and various studies on landslides were analyzed. A monitoring system was employed to track subsurface and surface movements, as well as changes in the groundwater table level. Additionally, numerical modeling using PLAXIS software was performed to evaluate the impact of construction activities, particularly the rise in the groundwater table, on slope stability. The obtained results demonstrated that the position of the groundwater table plays a crucial role in the stability of these structures, underscoring the importance of considering local hydrogeological conditions in the planning and execution of such projects. It is concluded that the complexity of such phenomena in slopes with similar geological, geomorphological, hydrogeological, and geotechnical characteristics is a significant issue that requires particular attention during the planning and execution of such projects. [ABSTRACT FROM AUTHOR]

The hydrological processes within the catchment are generally influenced by both climate change (CC) and land use/land cover (LULC) change. However, most of the studies are focused on their individual impact on the catchment’s hydrology, while their combined effects have received little attention. This study employs the physically based distributed hydrological model, MIKE SHE, to study the separate and combined effect of climate and LULC change on the hydrology of a mesoscale catchment in the near future (2050s). An Artificial Neural Network – Cellular Automata (ANN-CA) based prediction model was trained to simulate the future LULC map. The future meteorological data under four CC scenarios was obtained from the Royal Netherlands Meteorological Institute (KNMI). The model results showed that the combined effects of CC with LULC changes did not significantly differ from the individual impact of CC on the catchment scale. However, on the local scale, the changes in LULC can significantly influence the variations in groundwater table, soil moisture, and actual evapotranspiration ranging from approximately – 6–15%, – 9–27%, and – 30–10% respectively, depending on the specific change in LULC class and season. In summary, this research provides valuable insights into the complex interactions between LULC changes, CC, and hydrology. [ABSTRACT FROM AUTHOR]

We investigated the impact of water table (WT), monthly temperature, and precipitation of current and previous growing seasons on annual diameter growth of Scots pine in boreal drained peatlands. The data were collected from six sites across Finland. WT was monitored during 5–8 growing seasons depending on site during 2007–2014. The sites contained altogether 19 sample plots, where diameter growth from 339 trees was measured, resulting in 1599 growth observations. Tree-level diameter growth was analysed using mixed linear models, including variables describing tree size, competition, and environment. The higher precipitation in June of the previous year and May of the current year increased diameter growth, whereas the higher temperature in July of the current year and the deeper WT in August of the previous year decreased growth. The results suggest that Scots pine grows better at shallow than deep WT in drained peatlands. This contradicts earlier findings that a deep WT is needed to support tree growth in drained peatlands. We suggest that the development of a mor layer on the peat is changing nutrient cycling and hydrology. The results encourage the avoidance of intensive drainage in forested peatlands, which may also diminish the adverse environmental impacts of peatland forestry. [ABSTRACT FROM AUTHOR]

Beach groundwater and nearshore hydrodynamic data were collected during a field experiment along two dissipative beach transects on Galveston Island, Texas, in the fall of 2023. The monitored beaches serve as nesting habitat for the critically endangered Kemp's ridley sea turtle. Conditions ranged from calm to stormy, with two storms occurring during the experiment, inundating the entire beach up to the dune toe. Collected hydrodynamic data include readings from pressure loggers submerged in the foreshore and mounted in groundwater wells in the backshore, data from two wave buoys about 1.5 km offshore, and GoPro timestacks of the instantaneous waterline (wave runup). Other collected data include bathymetry and topography surveys, subsurface temperature and moisture content readings, and sediment characteristics. This comprehensive dataset can be used to (1) study relevant beach inundation and groundwater processes, including their effect on the local ecosystem (e.g., repeated flooding of sea turtle nests), (2) study the propagation of nearshore hydrodynamic processes into the beach matrix and groundwater table, and (3) validate existing beach groundwater models. [ABSTRACT FROM AUTHOR]

This paper addresses the mechanical characteristics of a passive earth pressure problem taking into account water retention curve (SWRC) hysteresis. Both hydraulic (drying and wetting cycles) and mechanical hysteresis were considered. Parametric studies were carried out at various air entry values (AEV = 5–30 kPa), different wall frictions (δ = 0, 0.33 ϕ, 0.5 ϕ, 0.67 ϕ and δ = ϕ), and unsaturated conditions (covering the zone from the fully saturated to the transition suction, 0 - ~40 kPa) using an upper bound theorem. The numerical results were compared with a passive earth pressure equation based on the limit equilibrium method. The results indicated significant influences of SWRC hysteresis and wall frictions on the passive thrust (Pp) for the modeled suction profiles. An increase of 1.31-fold in Pp was obtained when the AEV changed from 10 to 20 kPa at the water table (Hw) = -2 m. Additionally, the combined effects of AEV and δ were found to be significant. An increase of 4.14-fold in Pp at Hw = -3 m was obtained when comparing the case of AEV = 30 kPa and δ = ϕ with AEV = 5 kPa and δ = 0. Based on the parametric studies, a series of design charts of the exerted passive thrust were proposed. [ABSTRACT FROM AUTHOR]