Groundwater Level Changes Research Articles

A groundwater level spatiotemporal prediction model based on graph convolutional networks with a long short-term memory

ABSTRACT The performance of regional groundwater level (GWL) prediction model hinges on understanding intricate spatiotemporal correlations among monitoring wells. In this study, a graph convolutional network (GCN) with a long short-term memory (LSTM) (GCN–LSTM) model is introduced for GWL prediction utilizing data from 16 wells located in the northeastern Xiangtan City, China. This model is designed to account for both the hybrid temporal dependencies and spatial autocorrelations among wells. It consists of two parts: the spatial part employs GCNs to extract spatial characteristics from a spatial self-similarity weight matrix and an attribute self-similarity wight matrix among wells; the temporal part utilizes a LSTM module to capture the temporal patterns of GWL sequences, along with monthly precipitation and temperature data. This model dynamically predicts changes in groundwater levels, achieving higher accuracy on average compared to single-well predictions using LSTM. By incorporating both temporal dependencies and spatial autocorrelations, the GCN–LSTM model demonstrated an average improvement in goodness-of-fit of approximately 11.21% over the LSTM-based model for individual wells. Its application holds significant reference value for the sustainable utilization and development of groundwater resources in Xiangtan City.

Monitoring seismic velocity changes at Campi Flegrei (Italy) using seismic noise interferometry

Campi Flegrei is a volcanic field located west of Naples (Italy) in a densely populated area. Since 2005, its ground has been rising steadily due to the accumulation of fluids at shallow depths. The inflation of volcanic edifices is a possible precursor of an impending eruption. The uplift is accompanied by increasing seismic activity. This raises concerns about the possibility that the volcano may be on the verge of an eruption. To track the fluid movement, it is possible to monitor subtle changes of velocities of seismic waves by exploring ambient seismic noise. By examining different frequency bands, we can observe velocity changes at different depths. We interpret these changes as a monitoring of depth-dependent deformation in addition to the standard monitoring of surface deformation. We observe a velocity decrease in the long-term trend, presumably due to the extension of the hydrothermal system at shallow depths. To explain the long-term changes, we model a spherical pressure source to simulate volumetric strain changes induced by recent fluid activity. The model explains both, surface and subsurface deformation which leads to the opening of microcracks and pores, resulting in the observed velocity decrease. The short-term velocity changes are mainly driven by temperature or groundwater level changes. Once velocity changes are corrected for seasonal effects, remaining short term velocity changes can be associated with volcanic activity and earthquake swarms.

Integration of multiple observations for validation of mechanisms of earthquake-triggered groundwater level Anomalies: 2016 Taiwan Meinong earthquake

This study analyzes multi-depth groundwater level data and integrated observation data to validate the previously proposed mechanisms of hydrological anomalies triggered by the 2016 M6.4 Meinong earthquake in Taiwan. The main influence area was northwest of the epicenter, which may be due to the blind fault rupture, intensity distribution, and hydrogeological properties. The step changes in groundwater level do not fit the concept of epicentral distance, static stress–strain theory, or the focal mechanism. The distribution of step changes in groundwater level have a pattern similar to that of horizontal peak ground velocity. The results imply that these changes may be driven by dynamic stress–strain, instead of static stress–strain. The minimum horizontal peak ground velocity and acceleration of the Meinong earthquake, which induced obvious step changes in groundwater level and soil liquefaction, are provided. The pressure dissipation ability of an aquifer (e.g., transmissivity) may affect the persistence of groundwater responses. Four wells located near the surface rupture area, which has cemented or partial cemented geological material, showed an obvious step decrease in the groundwater level at a deep depth and all wells showed an increase in the groundwater level at a shallow depth. These decreases and increases of the groundwater level at different depths have different mechanisms, which are discussed in this study. The integrated observations made during the Meinong earthquake show that ground motion and the hydraulic properties might be important factors in hydrological anomalies. The results of this study are an important reference for further studies on earthquake hydrology.

Very‐Near‐Field Coseismic Fault Pressure Drop and Delayed Postseismic Cross‐Fault Flow Induced by Fault Damage From the 2018 M6.3 Hualien, Taiwan Earthquake

AbstractEarthquakes can produce rock damage, poroelastic deformation, and ground shaking that modify fault zone hydrogeologic properties. Coseismic and postseismic hydrologic response to the ruptured fault can serve as constraints on hydrogeologic property changes. Here, we document fluid pressure responses to the 2018 M6.3 Hualien, Taiwan earthquake and model the postseismic fault zone hydrology inferred from very‐near‐fault data. Two groundwater wells located ∼180–250 m from the fault damage zone experienced 10–15 m of groundwater level decline followed by a prolonged (>6 months) recovery. Poroelastic models indicate that strain dilation in the fault's hanging wall can produce water level reductions of several meters. However, the model cannot explain groundwater level change in the footwall nor the delayed postseismic recovery, suggesting fault zone damage played a primary role in both the coseismic and postseismic water level reductions. Fluid flow models incorporating the effects of coseismic fault damage on the temporal evolution of hydrologic fault properties show enhanced hydraulic anisotropy after the earthquake. The best‐fit models show that while both vertical hydraulic conductivity and specific storage likely increased within the fault zone, the horizontal hydraulic conductivity is low, suggesting the fault zone behaves as a hydraulic barrier to cross‐fault flow with modeled diffusivities as low as ∼10−3 m2/s. High‐fidelity hydrologic measurements in the very‐near‐field of fault zones (e.g., within a few hundred meters) may be a useful tool to constrain the spatial and temporal evolution of fault zone properties before, during, and after rupture.

Determining the Effective Meteorological Parameters on Potato Yield in Niğde Province and Yield Prediction with Machine Learning and Deep Learning Models

In this study, we explore the impact of meteorological parameters on potato yield in Nigde province, a key agricultural region in Turkey for potato production. Understanding the relationship between weather conditions and crop yield is crucial for optimizing agricultural practices and ensuring food security, especially in regions susceptible to climate variability. The study includes all meteorological parameters observed and recorded in Nigde Directorate of Meteorology, covering the period between 1990 and 2023. Through the analysis of historical weather data and potato yield records, we aim to identify the most influential meteorological factors affecting potato production. Then, artificial intelligence techniques such as Random Forest, Gradient Boost, Convolutional Neural Networks and Recurrent Neural Networks are utilized to predict the potato yield in order to provide valuable insights into how different weather patterns influence crop performance. The findings suggest that potato yield is correlated with meteorological parameters to some degree and AI techniques can predict the potato yield but lacks the precision. The reason is that potato production in Nigde is mostly done with irrigation. However, this further increases the risk that could result from the changes in groundwater levels and pollution in irrigation ponds for agricultural practices in Nigde.

Investigation of groundwater level change and its impact on slope stability in the Sector-E of Afsin-Elbistan Open-Pit Lignite Mine in Turkey

Investigation of groundwater level change and its impact on slope stability in the Sector-E of Afsin-Elbistan Open-Pit Lignite Mine in Turkey

Effects of groundwater level changes on soil characteristics and vegetation response in arid and semiarid coal mining areas.

Coal mining in arid and semiarid regions often leads to numerous ecological and environmental problems, such as aquifer depletion, lake shrinkage, vegetation degradation, and surface desertification. The drainage from coal mining activities is a major driving force in the evolution of the groundwater-soil-vegetation system. In order to explore the effect of groundwater level fluctuation on soil properties and the response mechanism of surface vegetation in coal mining areas, this study is based on hydrogeological and ecological vegetation investigations in the Bojianghaizi Basin, and soil and vegetation samples are collected in the areas with different groundwater levels, and soil and vegetation indexes are analyzed with the aid of methods such as numerical statistics, linear regression, and correlation analysis with the aid of the Origin software. The results show that there is a significant negative correlation between groundwater table (GWT) and soil water content (SWC), soil conductivity, soil organic matter (SOM), soil available nitrogen (SAN), and soil available potassium (SAK). Mining activities have led to the destruction of the soil structure, greatly reducing its ability to retain water and fertilizer. The contents of SWC, SOM, and SAN in the mining area are significantly reduced, which are at least 49.73%, 47.56% and 59.90% lower than those around the mining area. On the northern and southern sides of the lake, serious soil salinization exists in the lakeshore zone where the depth to the water table is <0.5m, and the water required for the growth of vegetation here mainly comes from the groundwater, so there are only a few water-loving and saline-resistant plants; when the depth to the water table is 0.5-7m, the growth of surface vegetation is influenced by the double impacts of the water table and atmospheric precipitation with a high degree of species richness; when the depth to the water table is >7m, the surface vegetation is only dependent on the limited atmospheric precipitation for water. When the depth of groundwater is >7m, the surface vegetation only relies on limited atmospheric precipitation for water, and drought-tolerant plants mainly grow in these areas. This study not only provides a scientific basis for the sustainable development and environmental protection of similar mines in the world, but also has important significance in guiding the ecological management and rational utilization of water resources in coal mine areas. What is more, This study provides valuable insights into sustainable water resource management in arid and semi-arid regions, crucial for mitigating the ecological impacts of coal mining activities.

Influence Mechanism of Water Level Variation on Deformation of Steep and Toppling Bedding Rock Slope

The construction of major hydropower projects globally is challenged by slope deformation in reservoir areas. The deformation and failure mechanisms of large rock slopes are complex and poorly understood, making prevention and management extremely challenging. In order to explore the influence mechanism of the water level variation on the deformation of steep toppling bedding rock slopes, this paper takes the right bank slope near the dam area of the Longtou Hydropower Station as an example, and field investigations, deformation monitoring, physical simulation tests and numerical analyses are carried out. It is found that the slope deformation response is obvious under the influence of the reservoir water level variation, which is mainly reflected in the change in the slope groundwater level, rock mechanical parameters and seepage field in the slope body. The toe of the slope produces plastic deformation and maximum displacement. With the increase in the reservoir water level, the plastic zone expands and the displacement increases, which leads to the intensification of the slope deformation. This paper puts forward that the deformation and failure modes of the steep and toppling bedding rock slope caused by water level variation are due to shear dislocation, bending deformation and toppling fracture. This study reveals the influence mechanism of the water level variation on the deformation of steep and toppling bedding rock slopes, which can provide theoretical support for the construction of major hydropower projects.

Response of dissolved organic carbon in streams draining peatbogs to extreme rainfall-runoff events: a case study from Šumava (Bohemian Forest) National Park, Czech Republic

The presented study investigates the dynamics of DOC concentrations in headwater peatbog areas with respect to the extreme rainfall-runoff (R-R) events hydrometeorological catchment preconditions (23 variables in total). The main data sources were automatic devices for monitoring of groundwater level, discharges and rainfalls providing data in 10 min steps installed in the Vydra River catchment and one automatic water sampler ISCO in sub-catchment of the Rokytka River basin in the Šumava (Bohemian Forest) National Park. The study period was 2018–2021, in which 18 R-R events were analysed. Data of DOC variability and catchment conditions were analysed using Spearman’s correlation coefficient, Principal Component Analysis and DOC/Q hysteresis loops. Changes in groundwater level and discharges had the greatest influence on DOC concentrations. Higher mean and maximum DOC were measured during events after a longer period without an extreme R-R event. The greater lag time of maximum DOC after peak flow and the higher mean DOC during the event were primarily due to hydrometeorological preconditions of the catchment. The highest DOC was in autumn after the previous summer period with low discharges and low groundwater levels. DOC was also positively correlated with air and water temperatures.

Rising damp in heritage sites under urban expansion: A comprehensive case study of the Jinsha Earthen Site

Rising damp poses a significant threat to cultural heritage, yet its dynamics within actual heritage sites remain inadequately understood, particularly regarding its evolution and the impact of urbanization. The Jinsha Site, an earthen site from the Shang periods, is primarily composed of silt, with a layer of sand beneath and pebbles at the bottom, making it susceptible to rising damp. This study investigates the Jinsha Site as a case, monitoring soil water content and electrical conductivity, tracking changes in groundwater, precipitation, and river water levels, and investigating the relationship between urbanization and rising damp. The study aims to understand the process, causes, and influencing factors of rising damp and evaluate previous preservation strategies. The findings indicate that groundwater level in the sand layer trigger dampness, whereas the pebble layer exhibits dryness. Urban construction from 2006 to 2013 and 2014–2017 caused fluctuating groundwater levels, leading to repeated transitions between dryness and dampness at the site. Rainfall and river levels have negligible effect; even rainfall exceeding 100 mm (frequency <0.0056) only raises groundwater levels by approximately 1 m and increases water content by less than 2 % for a brief duration, typically less than half a month. The 2022 groundwater pumping strategy effectively maintained levels beneath the pebble layer (506 m), decreasing moisture by 12.71 % and conductivity by 0.27 dS/m. This study reflects on previous protection effortsand offers evidence-based strategies for heritage conservation amidst urban expansion.

Chronostratigraphy of the Late Glacial Żabinko site (western Poland) and investigation of the dose rate variability

The Żabinko exposure (western Poland) reveals the classic fluvio-aeolian succession known from studies in the European Sand Belt. Previous chronostratigraphic studies were mainly based on uncalibrated radiocarbon dates from organic sediments and thermoluminescence dating. The picture visible from these studies indicated a number of discrepancies between these methods. The new research in this exposure was based on optically stimulated luminescence (OSL) dating and calibrated radiocarbon dates. The results obtained indicate a general discrepancy between the results achieved by these two methods. While the radiocarbon dates provide some meaningful picture and allow correlation with previous studies, the results of OSL dating do not allow for a chronological model of sedimentary processes. The OSL dates show large inversions of the results and are clearly younger than the other dating results. Detailed analysis of OSL measurements shows radioactive disequilibrium and variability linked to differential stratification of sediments, significantly impacting the assessment of environmental dose rates. We believe that this atypical variability is presumably the result of postdepositional processes, such as changes in groundwater levels, chemical weathering and radionuclide migration.

The Importance of seismic microzonation under the threat of an earthquake of the north anatolian fault in nilüfer, bursa, turkiye

The Nilüfer district experienced the most recent urbanization among the central districts of Bursa in South Marmara region with the completion of rapid construction. Since 358 BCE, many destructive earthquakes were reported on the branches of the North Anatolian Fault (NAF) which caused extensive damage to buildings and loss of life near Bursa city. Besides some studies conducted to define the soil behavior in the vicinity of Bursa, a seismic hazard study in Nilüfer is still lacking. We, therefore, carried out a microzonation study including the following steps. First, an earthquake hazard analysis was conducted and the peak ground acceleration (PGA) values were determined for an expected earthquake. In the next step, MASW (Multi-Channel Analysis of Surface Wave) measurements conducted at 54 points in 28 neighbourhoods of Nilüfer district were evaluated. Soil mechanical parameters were determined at 11 boreholes to assess the liquefaction potential. It was found that almost half of the study area suffers from low damage considering only the vulnerability index (Kg) index, which depends on the site effect. Therefore, in addition to the Kg values, we created a microzonation map using the results of soil liquefaction, settlement, changes in groundwater level, and the average values of spectral acceleration. The study area is classified by four damage levels changing from low to high. Using only the Kg index could not quantify the potential damage level in the study area, thus we showed that the districts of Altınşehir, Hippodrome, Ürünlü and Alaaddinbey, Ertuğrul, 29 Ekim, 23 Nisan, Ahmetyesevi and Minareliçavuş were identified at potentially high-risk damage zones. The results of this study clearly showed that considering the Kg index, which depends only on the local site effect, may lead to inadequate damage values.

Estimation of groundwater-level changes based on GRACE satellite and GLDAS assimilation data in the Songnen Plain, China

Estimation of groundwater-level changes based on GRACE satellite and GLDAS assimilation data in the Songnen Plain, China

Shallow water table rise and fluctuation between 1977 and 2010 in Madinah City, Saudi Arabia

Madinah City in Saudi Arabia is rapidly growing with high population growth, water demand, sewage generation, and agricultural activities. The hydrogeological layering sequence in Madinah City reveals that there are three main layers that extend within the areas between wadi systems. The shallow water table rise (SWTR) problem has risen in several areas of the city, and the fluctuations in the piezometric water observed from the shallow aquifer systems. The research aims to investigate the changes in shallow groundwater levels within the Madinah City. Sources of water table rise and fluctuations are investigated through an extensive field hydro-geological survey comprising wells drilling and water level monitoring, which indicated the following results between 1977 and 2010 including those of newly drilled wells: (i) water flow is partially blocked along wadi Alaqiq and this has caused an increased regional flow moving from west along wadi Alaqiq towards the central area; (ii) groundwater levels have changed in the agricultural areas as indicated by 15–26 m rise along wadi Alaqiq; (iii) groundwater level fluctuations as indicated by 590 m amsl (1977) against less than 575 m amsl (2010) in the east and southeast of the study area as a result of increased heavy pumping since past 37 years. The overall flow phenomenon is reflected in the groundwater gradients on an increasing trend with orientation from the western region along the wadi Alaqiq towards the central area and southeast which has invariably resulted in the overall declining of water levels throughout the affected area.

Spatiotemporal variations of groundwater and gully impact in two peatland watersheds in the Upper Yellow River, Qinghai‐Tibet Plateau

AbstractThe spatiotemporal variability of groundwater level is an important property of peatland hydrology that directly alternates water storage. Nonetheless, the current understanding of the variations of groundwater level over long periods of time remains limited. In this study, we investigated two peatland watersheds (0.151 km2 for Watershed 1 and 0.844 km2 for Watershed 2) in the Zoige Basin in the upper watershed of the Yellow River to monitor temporal variability of groundwater level using self‐recorded water loggers over 4 years (2017–2021). The main results demonstrate that (1) groundwater level variations were controlled by gully drainage in sites adjacent to the gully but were more affected by rainfall in sites distant from the gully. The groundwater level near the gully downcut was lower than that near the gully without complete downcutting through the pear layer, with a maximum difference of 58.3 cm, indicating the longitudinal effect of groundwater level in the watershed. (2) Because the rainfall had a lag effect on the groundwater level, the length of lag gradually decreased with increased rainfall intensity (i.e., the lag time for sites distant from the gully was about 18 min shorter than that of sites close to the gully in Watershed 1). (3) The peak values of the groundwater level occurred simultaneously with the maximum and minimum rainfall in Watershed 2, and the peak occurrence time was related to the ratio of precipitation to evaporation. In the downstream sites, the groundwater level fluctuated more than the upstream ones in Watershed 2. Moreover, the average groundwater level in the upstream sites was 14.3 cm higher than that of the middle ones, indicating a decreasing trend of water storage along the gully. (4) The differences in groundwater level between wet and dry seasons were clear, but the difference was smaller in the upstream sites due to limited gully incision and higher water storage within the peat layer. Additionally, groundwater level changes were more extreme on rainy days during both the wet and dry seasons, but the different intensities of rainfall resulted in stable groundwater in the dry season and an oscillating groundwater level in the wet season in Watershed 2. This study uncovers the groundwater dynamics in the two peatland watersheds, which is of great significance for understanding runoff variation, ecohydrological processes, and wetland shrinkage.

Drivers of Daily Water Level Fluctuation of Shallow Groundwater in the Inner Delta of the River Danube

Groundwater flow systems are influenced by the changes in surface waters as well as climatic factors. These teleconnections significantly increase in cases of extreme weather conditions. To prepare and mitigate the effect of such phenomena, the background factors that create and influence natural processes must be recognized. In the present study, 94 shallow groundwater (SGW) wells’ water level time series were analyzed in the inner delta of the River Danube (Europe) the Szigetköz region to explore which factors contribute to the development of diurnal periodicity of SGW and what its drivers are. The relationship between surface meteorological processes and SGW dynamics in the Szigetköz region was investigated using hourly data from monitoring wells. Hourly water temperature data exhibited weak correlations with meteorological parameters. However, daily averaged data revealed stronger correlations, particularly between SGW levels and air temperature and potential evapotranspiration. Diurnal periodicity in SGW fluctuations correlated strongly with potential evapotranspiration. The study also demonstrated the role of capillary fringe dynamics in linking surface evapotranspiration with SGW fluctuations. Changes in groundwater levels, even small, can significantly affect soil moisture, vegetation, and ecosystem functioning, highlighting the sensitivity of the unsaturated zone to SGW fluctuations driven by surface processes.

An integrated approach for characterization of a fractured-rock carbonate aquifer in the Zagros Region of Iran

Karst aquifers typically exhibit a wide range of dissolution effects that include end-members of matrix, fractured-rock, and conduit-dominated types. This study employs an integrated approach involving geological studies, hydrogeological assessments, hydrochemical and isotopic analysis, and dye tracer tests to investigate the Sarvak limestone aquifer (SLA) in the Zagros Region, southwest Iran. Key characteristics of the SLA include numerous stratification boundaries, thin limestone layers with intercalated siliceous and marl impurities, extensive joint and fracture networks, predominant autogenic recharge, and absence of notable point recharge features (e.g., sinkholes, dolines), and the exchange flow with the Bakhtiari River (B-R) has made it a unique aquifer. Numerous pieces of evidence, such as low spatial and temporal changes in groundwater level, insignificant seasonal variations in the hydrochemical and isotopic composition of water samples, and the supersaturation state of groundwater with calcite and dolomite minerals, suggested a slow flow regime in many parts of the SLA. This regime is characterized by low velocity and long residence time of groundwater. The results reveal that despite the high solubility of carbonate rocks, extensive joint networks can limit significant karst development, leading to fluid flow behavior similar to that of fractured-rock aquifers. Therefore, SLA can be considered a fractured-rock and karst aquifer. The identified paths with fast flow in the dam area are unremarkable and cannot provide a large portion of the Pelle Khan Spring discharge.

Experimental study on migration characteristics of LNAPL in the aquitard under pumping conditions.

Research on the migration behaviors of contaminants in the aquitard has been deficient for an extended period. Clay is commonly employed as an impermeable layer or barrier to stop the migration of contaminants. However, under certain conditions, the clay layer may exhibit permeability to water, thereby allowing contaminants to infiltrate and potentially contaminate adjacent aquifers. Consequently, it holds immense importance to scrutinize and investigate the migration characteristics of light non-aqueous phase liquid (LNAPL) within the aquitard for the purposes of groundwater pollution control and remediation. To evaluate the environmental risk posed by organic contaminants in the aquitard, an experimental model was formulated and devised to monitor the LNAPL concentration in the aquitard under pumping conditions. The correlation between pumping rate and LNAPL concentration was investigated. A self-developed plexiglass sandbox model was used to simulate the migration characteristics of LNAPL in the aquitard under pumping conditions. Four experimental scenarios were designed, varying pumping rates, aquitard thicknesses, and groundwater level changes. The LNAPL concentration curve was derived by systematically tracking and analyzing LNAPL levels at various locations within the aquitard. The results indicated that higher pumping rates corresponded to increased migration of LNAPL, resulting in greater LNAPL ingress into the pumping well during extraction. A thicker aquitard demonstrated a more pronounced inhibitory effect on LNAPL, leading to an extended penetration time of LNAPL within the aquitard. The drawdown within the aquitard exerted a discernible influence on LNAPL migration, with the LNAPL concentration continuing to decrease in tandem with declining water levels during pumping. These research findings can establish a scientific foundation for the control and remediation of contaminants within aquitards.

Surface Subsidence Characteristics and Causes Analysis in Ningbo Plain by Sentinel-1A TS-InSAR

In recent years, the Ningbo Plain has experienced significant surface subsidence due to urbanization and industrialization, combined with the area’s unique geological and hydrological conditions. To study the surface subsidence and its causes in the Ningbo Plain, this study analyzed 166 scenes of Sentinel-1A SAR images between January 2018 and June 2023. The time series interferometric synthetic aperture radar (TS-InSAR) technique was used to acquire surface subsidence information in the area. The causes of subsidence were analyzed. The results show that: (1) the annual deformation rate of the Ningbo Plain ranges from −44 mm/yr to 12 mm/yr between 2018 and 2023. A total of 15 major subsidence zones were identified by using both the subsidence rate map and optical imagery. The most severe subsidence occurred in the northern industrial park of Cixi City, with a maximum subsidence rate of −37 mm/yr. The study reveals that the subsidence issue in the main urban area has been significantly improved compared to the 2017 subsidence data from the Ningbo Bureau of Natural Resources and Planning. However, three new subsidence areas have emerged in the main urban area, located, respectively, in Gaoqiao Town, Lishe Town, and Qiuyi Village, with maximum rates of −29 mm/year, −24 mm/year, and −23 mm/year, respectively. (2) The causes of subsidence were analyzed using various data, including land use data, geological data, groundwater-monitoring data, and transportation network data. It is found that a strong link exists between changes in groundwater levels, compressible layer thickness, and surface subsidence. The groundwater levels changes and the soft soil layer thickness are the main natural factors causing subsidence in the Ningbo Plain. Additionally, the interaction between static loads from large-scale industrial production and urban construction, along with the dynamic loads from transportation networks, contribute significantly to surface subsidence in the Ningbo Plain. The results from this study enhance the understanding of the driving factors of subsidence in the Ningbo Plain, which can provide necessary guidance for the economic development and decision-making in the region, helping to manage and potentially mitigate future subsidence issues.

Assessment of spatio-temporal variations in groundwater quality for the groundwater-dependent Maltese islands

Study regionMaltese islands Study focusThe Maltese islands are situated in the Mediterranean Sea, characterized by a semi-arid climate, and encounter increased levels of water stress. This study conducted a hydrochemical analysis of 35 groundwater samples to evaluate the suitability of the current groundwater for agricultural and domestic purposes. Additionally, three-dimensional numerical modeling was conducted to estimate long-term changes in groundwater levels and saline water distributions over 30 years, under the assumption that groundwater pumping will persist at the current rate. New hydrological insights for the regionSalinity factors that classify groundwater in this region can potentially be used for the irrigation of salt-tolerant crops. The output of the modeling calculations suggests that groundwater levels were expected to decrease significantly across most of the island, particularly around gallery areas. Descending the water table may compromise the discharge of coastal groundwater and potentially accelerate seawater intrusion into the inner island areas. Hydrochemical calculations indicated that an increase in salinity induced variations in saturation conditions, leading to a decrease in calcite and an increase in anhydrite, dolomite, and gypsum. The water quality characteristics and contamination evaluations conducted in this study are valuable for the development of long-term alternatives for water resource conservation in this region.