Search Results (133)

The morphologic dating of single-event fault scarps along the dextral strike-slip Valley Fault System (VFS) yielded distinct clusters of relative ages (kt), which we interpret as evidence of independent surface ruptures. The boundaries between structural and geometric segments of the East Valley Fault (EVF) appear to have been nonpersistent during the recent rupture cycle. We associate the youngest cluster with the largest historical earthquake (M > 7 in 1863) felt in Manila, which is believed to have come from three segments of the EVF. Thus, future multiple-segment events, M > 7, could occur on the EVF. Our results do not support rupturing of the entire length of the West Valley Fault (WVF), but its northern segment (segment I) is capable of generating an M > 7 earthquake. This is the first time that diffusivity and relative ages of fault scarps are determined from this part of the world and is one of the few studies applying analysis of recent fault scarps to rupture segmentation studies. The recent scarps along the WVF’s segment II are due to aseismic creep and occur along pre-existing tectonic structures. Continued groundwater overextraction within the creeping zone could induce seismicity and modulate the natural timing of future earthquakes along the WVF. Full article

This study aimed to assess the impact of climatic alteration on food security in Saudi Arabia. Date productivity, temperature, and precipitation represent the data which were collected from various sources linked to the study subject and cover the period from 1980 to 2023. The Engle–Granger two-step procedure, the VECM, and forecast analysis were applied to test the long-term relationship, short-term integration, and forecasting, respectively. Moreover, qualitative analysis was used to reveal the influence of climatic change on food security. The results discovered long-term co-integration between date productivity and temperature. Additionally, the results revealed that there has been long-running co-integration between date productivity and the precipitation series. Temperature and precipitation negatively and significantly impacted date productivity during the study period. With reference to forecast results, the graph was validated using various forecast indicators: the Alpha, Gamma, Beta, and Mean Square Error equivalents were 1.0, 0.0, 0.0, and 5.47, respectively. Moreover, the growth rates of date productivity were equal to 0.82 and 0.08 for the periods from 1980 to 2022 and 2023 to 2034 (forecast), respectively, indicating that there is a decrease in the growth rate of date productivity (0.08) during the forecast period. From these results, the conclusion is that climatic change (temperature and precipitation) negatively impacts date productivity. In addition, the growth rate during the forecast period decreased, indicating that climatic change is affecting food security currently and will continue to do so in the future. This study recommended specific policy interventions and innovations in agricultural practices, including developing and implementing a national framework focused on climate-smart agriculture, balancing productivity, adaptation, and mitigation. This could be aligned with Vision 2030 and the Saudi Green Initiative. Additionally, this could include investing in research and development by increasing public–private partnerships to support agricultural R&D in arid regions, with a focus on heat- and drought-resistant crop varieties and water-efficient farming systems. Regarding agricultural innovations, these could include the use of renewable energy, particularly solar energy, the expansion of rainwater harvesting infrastructure, recycling treated wastewater for agriculture, and reducing reliance on groundwater sources. Full article

Groundwater resources in the Kou sub-basin of southwestern Burkina Faso play a critical role in supporting domestic water supply, agriculture, and industry in and around Bobo-Dioulasso, the second-largest city in Burkina Faso. This study synthesizes over three decades of research on groundwater vulnerability, recharge mechanisms, hydrochemistry, and residence time across the region’s sedimentary aquifers. The Kou basin hosts a complex stratified system of confined and unconfined aquifers, where hydrochemical analyses reveal predominantly Ca–Mg–HCO₃ facies, alongside local nitrate (0–860 mg/L), iron (0–2 mg/L) and potassium (<6.5 mg/L–190 mg/L) contamination. Vulnerability assessments—using parametric (DRASTIC, GOD, APSU) and numerical (MODFLOW/MT3D) models—consistently indicate moderate to high vulnerability, especially in alluvial and urban/peri-urban areas. Isotopic results show a deep recharge for a residence time greater than 50 years with deep groundwater dating from 25,000 to 42,000 years. Isotopic data confirm a vertically stratified system, with deep aquifers holding fossil water and shallow units showing recent recharge. Recharge estimates vary significantly (0–354 mm/year) depending on methodology, reflecting uncertainties in climatic, geological, and anthropogenic parameters. This review highlights major methodological limitations, including inconsistent data quality, limited spatial coverage, and insufficient integration of socio-economic drivers. To ensure long-term sustainability, future work must prioritize high-resolution hydrogeological mapping, multi-method recharge modeling, dynamic vulnerability assessments, and strengthened groundwater governance. This synthesis provides a critical foundation for improving water resource management in one of Burkina Faso’s most strategic aquifer systems. Full article

With the ongoing urbanization and densification of cities worldwide, the planning and utilization of urban underground space (UUS) have become crucial for developing urban underground infrastructure. Given the limited construction space within dense urban areas and the influence of declining groundwater levels, technologies such as open caissons and various vertical shaft methods have been introduced for UUS development. However, the dissemination of these technologies remains fragmented across different domains, lacking systematic summarization. A comprehensive, up-to-date overview of open caisson and vertical shaft technologies is essential for their effective application. In the manuscript, a systematic analysis of vertical shaft technologies, specifically focusing on their use in soft ground conditions, is conducted. The analysis is based on an extensive literature review and case study evaluation. It addresses the unique challenges posed by high compressibility, low bearing capacity, and groundwater sensitivity. Conventional shaft technologies and mechanized systems, including open caissons, drilled shafts, and the novel pressed-in ultra-deep assembled shafts (PIAUS), are evaluated systematically. Key aspects such as design principles, construction techniques, and stability in soft soils are discussed. The limitations of conventional methods in soft UUS are highlighted, while the advantages of advanced mechanized systems—such as rapid construction, reduced environmental impact, and improved safety—are emphasized. A detailed comparison of case studies demonstrates that PIAUS construction technology is particularly efficient in urban areas with confined spaces, dense building conditions, and ground conditions up to 200 MPa, with shaft diameters up to 12.8 m and depths of 115.2 m. Additionally, its suitability for rapid construction in soft and medium ground conditions is supported by undrained excavation with parallel excavation and liner sinking techniques. The PIAUS technology shows considerable potential for future projects, including shield construction shafts, ventilation shafts for tunnels, underground parking garages, and stormwater storage wells. This manuscript also highlights emerging mechanized methods in underground space development, their advantages, limitations, and areas for future research and improvement. Full article

The presence of heavy metals in groundwater and wastewater has been a concern for health organizations. This study investigated the effectiveness of activated carbon derived from various natural precursors, including acorns from red oak trees (Quercus rubra), date seeds, and peach seeds, employing the thermal activation method for the removal of heavy metals from aqueous solutions. Batch adsorption tests investigated the effects of sorbent quantity, pH levels, disinfectant presence, and dissolved organic matter (DOM) on the removal efficiency of Pb and Cu. Characterization of the prepared activated carbon was conducted using scanning electron microscopy (SEM). Lead removal efficiency diminished at pH 7 relative to pH 3 and 5, but copper exhibited superior removal efficiencies at pH 7 compared to pH 5. The addition of monochloramine at 4 parts per million (ppm) effectively eliminated lead from the solution. A rise in free chlorine concentration from 2 to 4 mg/L led to a reduction in metal removal from water by 20 to 60%. DOM at concentrations of 1 and 6 mg/L reduced metal removal efficacy relative to DOM at 3 mg/L. Date seed-activated carbons underscore their distinctive potential, offering useful insights for the enhancement of water and wastewater treatment systems. Full article

Oases are part of the natural wealth and heritage of Morocco and contribute to the social, economic, and touristic environment. Morocco has lost more than 2/3 of its oases during the past century due to water scarcity, succession of drought periods, climate change and over-exploitation of groundwater resources. Palm trees are strongly dependent on irrigation and availability of surface water as soon as the water table depth falls below the root zone of 9 m. Improving management and monitoring of oasis ecosystems is strongly encouraged by UNESCO Biosphere Reserve and RAMSAR guidelines. The Boudenib and Tafilalet oases are among the biggest palm groves located in the south-eastern part of Morocco. These oases belong to catchments of the rivers Guir and Ziz, respectively. This paper uses remotely sensed data from PROBA-V for monitoring vegetation in oases, and linking vegetation characteristics to water availability, water management and quality and quantity of date crops. The Normalized Differential Vegetation Index (NDVI) derived from optical images provides a good estimation of changes in vegetation cover over time. Images of various spatial resolutions (100 m, 300 m and 1 km) obtained with the frequently revisiting Belgian satellite PROBA-V and available since 2014, can be successfully used for deriving time series of vegetation dynamics. TREX—Tool for Raster data Exploration—is a Python-GDAL processing tool of PROBA-V NDVI images for analyzing vegetation dynamics, developed at the Vrije Universiteit Brussel and available online. TREX has various applications, but the main functionality is to provide an automatic processing of PROBA-V satellite images into time series of NDVI and LAI, used in vegetation monitoring of user-defined points of interest. This study presents the results of application of TREX in the arid ecosystems of the Boudenib oasis for the period 2014–2018. The resulting NDVI and LAI time series are also compared to time series of groundwater depth and date crops quantity and quality. Low LAI is observed when water depth is low, and the palm trees lose their greenery. Low LAI is also correlated to low quantity and quality of dates in October 2015 and October 2017. PROBA-V images can therefore be used for monitoring the health of palm trees in oasis environments. However, considering the fact that the PROBA-V satellite mission has ended, this approach could instead be applied to Sentinel-3 data using the same analysis. These results have important implications for water management in the area and can help decision-makers to make better decisions about prevention of water scarcity in the region. Full article

The Abelar pilot basin in Coruña (northwestern Spain) has been monitored for hydrological and hydrochemical data to assess the effects of eucalyptus plantation and manure applications on water resources, water quality, and nitrate contamination. Here, we report the machine learning analysis of hydrological and hydrochemical data from the Abelar basin. K-means cluster analysis (CA) is used to relate nitrate concentrations at the outlet of the basin with daily interflows and groundwater flows calculated with a hydrological balance. CA identifies three linearly separable clusters. Times series Gaussian process regression (TS-GPR) is employed to predict surface water nitrate concentration by incorporating hydrological variables as additional input parameters using a time series shifting. TS-GPR allows modelling nitrate concentrations based on shifted interflows and groundwater flows and chemical concentrations with R² = 0.82 and 0.80 for training and testing, respectively. Groundwater flow from five days prior to the current date, $Q_{g5}$, is the most important input parameter of the TS-GPR model. Interaction effects between the variables are found. TS-GPR validation with recent data provides results consistent with those of testing (R² = 0.85). Model inspection by permutation feature importance and partial dependence plots shows interactions between $Q_{g5}$ and Cl, and between Ca and Mg. Full article

Due to climate change, water scarcity, and overexploitation of aquifers, the sustainable management and protection of groundwater resources will be one of the main challenges in the future. Therefore, the knowledge of hydrogeological characteristics, which must be as robust as possible, becomes crucial for defining groundwater management plans. On the other hand, the earliest evidence of the fertile plains and abundant water resources of Skydra and its surroundings dates back to the Neolithic period (6500–3200 B.C.), confirming the area’s current agricultural vocation and productivity. In this perspective, the aim of the present study is to define the conceptual hydrogeological model of a complex confined multi-aquifer system characterizing the volcano-sedimentary deposits of the Skydra area, northern Greece. In particular, the architecture of the hydrostratigraphic units, the hydraulic parameters, and the hydrodynamic behavior of the multi-aquifer system were analyzed. The geological, geomorphological, and structural evolution affecting the area has influenced the geometric and hydraulic characteristics of the aquifer, and consequently its productivity. The thickness of the multi-aquifer system varies between 25.0 and 94.5 m and the hydraulic conductivity, calculated through the analysis of data from 72 pumping tests, and the application of empirical method (42 wells), ranges between 2.2 · 10⁻⁶ and 2.5 · 10⁻³ m/s. Higher hydraulic conductivity values are calculated in areas where tuffaceous formations are fractured and/or interlayered with sandy layers; while lower values occur where tuffs present only primary porosity and are interspersed with frequent clay layers. In the central area, due to overexploitation of the aquifer, an annual piezometric level drop of approximately 6 m has been recorded. The information acquired could serve as the basis for the sustainable development of groundwater resources in the test area and could also be applied in other similar hydrogeological settings. Full article

Karst aquifers in the Mediterranean region are crucial for water supply and agriculture but are increasingly threatened by climate change and overexploitation. The Jebel Zaghouan aquifer, historically significant for supplying Carthage and Tunis, serves as the focus of this study, which aims to evaluate its availability, quality, and vulnerability to ensure its long-term sustainability. To achieve this, various methods were employed, including APLIS and COP for recharge assessment and vulnerability mapping, SPEI and SGI drought indices, and stable and radioactive isotope analysis. The findings revealed severe groundwater depletion, primarily caused by overexploitation linked to urban expansion. Minimal recharge was observed, even during wet periods. APLIS analysis indicated moderate infiltration rates, consistent with prior reservoir models and the MEDKAM map. Isotopic analysis highlighted recharge from the Atlantic and mixed rainfall, while Tritium and Carbon-14 dating showed a mix of ancient and recent water, emphasizing the aquifer’s complex hydrodynamics. COP mapping classified 80% of the area as moderately vulnerable. Monitoring of nitrate levels indicated fluctuations, with peaks during wet years at Sidi Medien Spring, necessitating control measures to safeguard water quality amid agricultural activities. This study provides valuable insights into the aquifer’s dynamics, guiding sustainable management and preservation efforts. Full article

This study highlights the importance of distinguishing the mechanisms driving spatial and temporal variances in groundwater database analyses, with a particular focus on bacteriological contamination processes. Groundwater quality data from the Bourgogne-Franche-Comté region of France forms the basis of this investigation. Specifically, the SISE-EAUX database includes 3569 groundwater samples collected over various dates from 989 monitoring points. The methodology involves structuring the data into three distinct sets: (1) A spatio-temporal dataset without any conditioning; (2) A spatial dataset that assigns the mean values of each parameter to each sampling point; (3) A temporal dataset that captures deviations from the mean for each sampling point and parameter. These datasets enable a separate analysis of spatial and temporal variances. Principal component analysis (PCA) and parameter hierarchical clustering were used to compare the results, yielding valuable insights into the underlying processes. This analysis helps distinguish between factors related to geological or pedological spatial distributions and those associated with climatic events, such as intense rainfall episodes exhibiting seasonal patterns. Such differentiation enhances the understanding of fecal contamination vectors and nitrate pollution, which are often linked to surface and subsurface runoff in vulnerable catchment areas. While conceptually clear, the practical separation of spatial and temporal variability presents challenges. For example, catchments sensitive to surface water inflows during rainfall events are unevenly distributed across the region, correlating with specific natural environments. As a result, areas of high temporal variability are also well-structured spatially, underscoring the interdependence of these two types of variability. This complexity is exemplified by the behavior of iron, which varies in association with surface and subsurface parameters depending on spatial and temporal contexts. Additionally, asynchronous sampling and varying frequencies across sites lead to discrepancies in the average temporal data acquisition between points. These disparities can influence spatial variability calculations, as temporal variability effects are not entirely removed. Despite these challenges, the distinction between spatial and temporal components is essential for a deeper understanding of groundwater quality mechanisms. This refined approach improves diagnostic precision and supports more targeted and effective water resource management strategies. Full article

Salem, Massachusetts, is one of the oldest cities in the United States (1629) and its coastal location on the Atlantic helped create one of the wealthiest cities in America during the late 18th century, but today its coastal location threatens many of its buildings due to sea level rise and increased storm activity. The House of the Seven Gables, a National Historic Landmark District, consists of five important historic buildings, the most famous being The Turner Ingersoll Mansion (1668), more commonly known as The House of the Seven Gables. Considered one of the most important houses in America, it is also one of the most threatened historic buildings due to its location on Salem’s harbor. The House of the Seven Gables conducted a two-year study funded by Massachusetts Coastal Zone Management to evaluate the risks posed by climate change. This process included the use of data from groundwater monitoring wells and a tidal gauge installed on-site, along with soil samples and a detailed survey base plan including topography and subsurface infrastructure. The project team then used the Massachusetts Coastal Flood Risk Model (MC-FRM) to assess climate change impacts on the site in 2030, 2050, and 2070, and then created a plan for adaptations that should be implemented before those risks materialize. Strategies for adapting to storm surges, increasing groundwater, and intense surface water runoff were evaluated for their effectiveness and appropriateness for the historic site. The conclusion of the study resulted in a five-phase plan ending in the managed retreat of the historic buildings to higher ground on the existing site. This article goes beyond other research that suggests coastal retreats by demonstrating how to quantitatively evaluate current and future coastal issues with predictive models and how to set viable dates for adaptive solutions and a managed retreat. Full article

Interpretation of ⁴⁰Ar/³⁹Ar dates of alkali feldspar and U-Pb dates of apatite depends on the dominant mechanism of isotopic transport in these minerals, which can be either diffusion or fluid-assisted dissolution-reprecipitation. To clarify the contributions of these processes, we have conducted a holistic study of alkali feldspar, apatite and other minerals from the Mt. Isa Inlier in NE Australia. Mineral characterisation by electron microscopy, optical cathodoluminescence imaging and element mapping reveal a complex interplay of textures resulting from magmatic crystallisation, deuteric recrystallisation, local deformation with subsequent higher-temperature alteration, and finally ubiquitous low-temperature alteration. U-Pb and Pb isotopic data for zircon, apatite, fluorite and alkali feldspar suggest that the latter event occurred at ~300 Ma and was associated with fluid-assisted exchange of Pb isotopes between minerals in the same rock, causing some apatite grains to have ²⁰⁷Pb-corrected U-Pb dates that exceed their crystallisation age. However, this event had no unequivocal effect on the ⁴⁰Ar/³⁹Ar or Rb-Sr systematics of the alkali feldspar, which were disturbed by higher-temperature alteration at ~1450 Ma. The age of the latter event is derived from Rb-Sr data. ⁴⁰Ar/³⁹Ar dates are very scattered and suggest that ⁴⁰Ar redistribution proceeded by diffusion in the presence of traps in some places and by dissolution-reprecipitation with variable amounts of recycling in other places. Our results demonstrate the complex effects that interaction with limited amounts of fluids can have on ⁴⁰Ar/³⁹Ar dates of alkali feldspar and U-Pb dates of apatite and thereby reinforce previous critique of their suitability for thermochronological reconstructions. We further identify and discuss potential implications for noble gas geochronology of groundwaters and fission track dating of apatite. Full article

Monitoring groundwater pollution is an important issue in terms of analyzing threats to protected, environmentally valuable areas. The topographical and environmental characteristics of a given area are often mentioned among the factors affecting the dynamics and chemistry of groundwater. In this study, the random forest regression (RFR) model was used to determine the spatial distribution of selected metals, such as aluminum, calcium, iron, potassium, magnesium, manganese, sodium, and zinc. In the role of indicators describing terrain variability, derivatives of the digital elevation model (DEM) were employed, with a spatial resolution of 5 m, describing the topography of the terrain on a local scale, such as, among others, slopes, the aspect and curvatures of slopes, the topographic position index, and the SAGA wetness index, as well as generalized values determined for each sampling point of the areas contributing their runoff. In addition, environmental parameters were taken into consideration: forest habitat types, the structure of soil cover, and the seasons when samples were collected. This study used samples collected from 15 wells located in forested areas of the Wielkopolska National Park on seven dates. The results obtained show that random forest can be used with very good results to model the spatial variability of the concentrations of aluminum, potassium, magnesium, manganese, and sodium in groundwater. However, in the case of calcium and zinc, no correlations were found between the adopted indicators describing the spatial variability of the area and their concentrations in groundwater. In addition, the degree of importance of each predictor was determined in order to rank their importance in modeling the concentration of each of the metals in groundwater. The summary ranking of predictors indicates that the strongest influence on the predicted concentration of metals in groundwater is exhibited by profile curvatures, planar curvatures, multiscale TPI, and then the habitat type of the forest. On the other hand, curvature classifications, soil composition, and seasonality exhibit the smallest generalized impact on the results of modeling. Full article

The SWAT model primarily investigates sources of water pollution and conducts ecological assessments of surface water in contemporary hydrology and water resources research. To date, there have been limited accomplishments in the study of groundwater resources in China. The MODFLOW model currently primarily simulates groundwater levels and the migration of water quality, depending on the hydrological surface water data in the relevant area. This study aims to investigate the groundwater distribution characteristics of the middle and lower reaches of the Songhua River, a significant agricultural and grain production region in China. The research focuses on the middle and lower reaches of the Songhua River basin in Northeast China and employed the SWAT distributed hydrological model to simulate runoff. The monthly recorded runoff at Tongjiang Station in Jiamusi City was utilized to calibrate the model parameters. Consequently, the MODFLOW model was introduced to compare and assess the simulation outcomes of the SWAT model, ultimately ascertaining the distribution characteristics of shallow groundwater, groundwater recharge, recoverable volume, and groundwater levels in the Songhua River Basin. The findings indicate that: (1) The SWAT model demonstrates efficacy in the study region, achieving R² and NS values of 0.81 and 0.76, respectively, thereby fulfilling the fundamental criteria for scientific research. The MODFLOW model exhibits strong performance in the study region, achieving a periodic R² of 0.98 and a verification R² of 0.97, with the discrepancy between simulated and actual groundwater levels confined to 0.6 m, thereby satisfying the criteria for scientific research. (2) In 2011, 2014, and 2016, the groundwater recharge in the middle and lower sections of the Songhua River was 24.33 × 10⁸ m³, 30.79 × 10⁸ m³, and 32.25 × 10⁸ m³, respectively, aligning closely with the SWAT simulation results, while the average annual groundwater level depth was 8.17 m. (3) In the research area, groundwater recharging occurs primarily by atmospheric precipitation, while drainage predominantly transpires via groundwater as base flow, constituting 81.46%. Secondly, the recharge of shallow groundwater to deep aquifers is around 7.14%, with a minimal share attributed to vadose zone loss, constituting merely 2.1%. (4) From 2010 to 2016, the average groundwater runoff modulus of the middle and lower reaches of the Songhua River basin was 1.005 L/(s·km²), with a total recharge of 216.58 × 10⁸ m³ and a total recoverable amount of 105.11 × 10⁸ m³. The mean yearly supply was 25.11 × 10⁸ m³. The total groundwater recharge was 26.54 × 10⁸ m³ in the driest year (2011) and 33.25 × 10⁸ m³ in the year of most ample water (2016). Full article

In recent years, there has been a surge in interest concerning emerging contaminants, also known as contaminants of emerging concern (CECs), due to their presence in environmental matrices. Despite lacking regulation, these chemicals pose potential health and environmental safety risks. Disodium EDTA, a widely utilized chelating agent, has raised concerns regarding its environmental impact. The present work aimed to verify the presence of Disodium EDTA at the exit of eight wastewater treatment plants discharging into some losing streams flowing within a large alluvial aquifer. Conducted in the Province of Parma (Northern Italy), the research employs a multidisciplinary approach, incorporating geological, hydrogeological, chemical, and microbial community analyses. Following a territorial analysis to assess industries in the region, through the use of ATECO codes (a classification system for economic activities), the study investigated the concentration of Disodium EDTA in effluents from eight diverse wastewater treatment plants, noting that all discharges originate from an activated sludge treatment plant, released into surface water courses feeding the alluvial aquifer. Results revealed detectable levels of Disodium EDTA in all samples, indicating its persistence post-treatment. Concentrations ranged from 80 to 980 µg/L, highlighting the need for further research on its environmental fate and potential mitigation strategies. Additionally, the microbial communities naturally occurring in shallow groundwater were analyzed from a hydrogeological perspective. The widespread presence of a bacterial community predominantly composed of aerobic bacteria further confirmed that the studied aquifer is diffusely unconfined or semi-confined and/or diffusely fed by surface water sources. Furthermore, the presence of fecal bacteria served as a marker of diffuse leakage from sewage networks, which contain pre-treated wastewater. Although concentrations of Disodium EDTA above the instrumental quantification limit have not been found in groundwater to date, this research highlights the significant vulnerability of aquifers to Disodium EDTA. It reveals the critical link between surface waters, which receive treated wastewaters impacted by Disodium EDTA, and groundwater, emphasizing how this connection can expose aquifers to potential contamination. At this stage of the research, dilution of wastewaters in surface- and groundwater, as well as hydrodynamic dispersion within the alluvial aquifer, seem to be the main factors influencing the decrease in Disodium EDTA concentration in the subsurface below the actual quantification limit. Consequently, there is a pressing need to enhance methodologies to lower the instrumental quantification limit within aqueous matrices. In a broader context, urgent measures are needed to address the risk of diffuse transport of CECs contaminants like Disodium EDTA and safeguard the integrity of surface and groundwater resources, which are essential for sustaining ecosystems and human health. Full article