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This study examines the physicochemical parameters of leachate from an uncontrolled landfill in the town of Guercif before its remediation, and its impact on the Tafrata aquifer located beneath the landfill and the adjacent Oued Moulouya surface waters. The results revealed significant organic pollution in the raw leachate, characterised by high levels of BOD5 (13,141.56 mg O2/l), COD (89,821.38 mg/L), nitrate, nitrite, and orthophosphate. Additionally, elevated concentrations of metallic elements (Co: 3 mg/L, Cr: 11.7 mg/L, Pb: 3 mg/L) exceeded recommended standards. The analysis also detected high pollutant concentrations in groundwater (e.g. BOD5 at P1: 176.65 mg O2/L), COD at P1: 589.25 mg/L), nitrate at P1: 57.08 mg/L, nitrite at P1: 0.86 mg/L, ammoniacal nitrogen at P1: 1.112 mg/L) and surface (BOD5: 420.14 mg O2/L, COD: 797.86 mg/L, nitrate, nitrite, orthophosphate). These findings indicate significant percolation of polluted leachate into the natural bedrock. [ABSTRACT FROM AUTHOR]

Due to its unique gravimetric energy density and zero carbon emissions, hydrogen is a top priority for the development of future clean and sustainable energy systems. To satisfy energy demand, underground hydrogen storage (UHS) is being adopted. Among underground hydrogen storage sources, aquifers may be one of the best places for large-scale storage of hydrogen (H 2). However, there is still lacking to understand the operational parameters of UHS, which is essential to achieve better UHS performance. In this study, operational parameters such as hydrogen production time, hydrogen injection rate, hydrogen production rate, frequency and length of cycles, shut-in period, number of wells, and spacing of wells are the focus of numerical simulations. Form the results, some insights are obtained as follows: (1) At higher hydrogen injection rates, H 2 recovery performance declined due to the short contact time between hydrogen and water, as well as lateral expansion of the gas. (2) Optimizing the hydrogen production rate and ensuring sufficient production time were crucial for enhancing hydrogen production performance. (3) Shorter lengths and higher frequencies of storage cycles contributed to an increase in the cumulative hydrogen production volume. Moreover, introducing a shut-in period between the injection and production periods exhibited a detrimental effect on the performance of UHS. (4) In the dual-well configuration, cumulative hydrogen production volume and cumulative recovery efficiency experienced increases of at least 0.51 × 107 m3 and 9.27%, respectively. Concerning well spacing, its impact on the performance of UHS was slight. The effectiveness of UHS in aquifers was confirmed by these results. These understandings provide a certain basis for the optimization of operating parameters. • A comprehensive analysis of operational parameters for optimizing hydrogen storage in an aquifer was performed. • The recovery performance of hydrogen decreased as the injection rate varied. • Boosting hydrogen production rate and ensuring sufficient production time are essential for enhancing performance. • Introducing the shut-in period between the injection and production periods proved to be disadvantageous. • A significant improvement in hydrogen recovery efficiency was observed with an increase in the number of wells. [ABSTRACT FROM AUTHOR]

Barium (Ba) dissolution and mobilization in groundwater are predominantly controlled by sulfate because of the low solubility of barium sulfate (BaSO4) minerals. Naturally present at low concentrations in groundwater, elevated concentrations of Ba can occur as a result of anthropogenic activities, including use of barite in drill operations, and geogenic sources such as leaching from geological formations. No toxicity data exist for Ba with groundwater organisms (stygofauna) to assess the risk of elevated Ba concentrations. The present study measured Ba toxicity to two stygobiont Cyclopoida species: one collected from Wellington and the other from Somersby, New South Wales, Australia. Toxicity was measured as cyclopoid survival over 2, 4, 7, 14, 21, and 28 days in waters of varying sulfate concentration (<1–100 mg SO4/L). When sulfate was present, dissolved Ba concentrations decreased rapidly in toxicity test solutions forming a BaSO4 precipitate until dissolved sulfate was depleted. Barium in excess of sulfate remained in the dissolved form. The toxicity of Ba to cyclopoids was clearly attributed to dissolved Ba. Precipitated Ba was not toxic to the Wellington cyclopoid species. Toxicity values for dissolved Ba for the Wellington and Somersby cyclopoid species included a (21‐day) no‐effect concentration of 3.3 mg/L and an effective concentration to cause 5% mortality of 4.8 mg/L (at 21 days). Elevated dissolved Ba concentrations due to anthropogenic and/or biogeochemical processes may pose a risk to groundwater organisms. Further toxicity testing with other stygobiont species is recommended to increase the data available to derive a guideline value for Ba that can be used in contaminant risk assessments for groundwaters. Environ Toxicol Chem 2024;43:2501–2514. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

We have compiled the toxicity data on stygofauna and other aquatic subterranean organisms in one (eco)toxicological database. A total of 46 studies were found, containing 472 toxic endpoints covering 43 different stressors. These compounds were tested on subterranean organisms from four phyla, 12 orders, 24 genera, and 55 species. The studies included were published between 1976 and December 2023 using fauna collected in 13 different countries. The suitability of the studies was assessed to indicate the completeness of reporting and their suitability for use in hazard and risk assessment. This compilation provides a valuable source of data for future development of toxicity testing protocols for groundwater organisms, and to support decision‐making, ecological risk assessments and the derivation of water quality criteria for the protection of groundwater ecosystems. Environ Toxicol Chem 2024;43:2492–2500. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Long-term coal mining activities have significantly disturbed the groundwater system, resulting in aquifer water characterized by high levels of Na+, SO42−, and total dissolved solid (TDS), posing environmental health risks. To investigate the disturbance effects of coal mining activities on the groundwater system and ascertain the goaf water (OGW) environmental impacts, this study focuses on the surface water (SW), major aquifers, and OGW of Jiaozhuang Coal Mine. Through ion analysis and self-organizing map (SOM) clustering, the study analyzes the hydrochemical characteristics of the aquifer water, summarizes the accumulation patterns of OGW, and evaluates water quality of irrigation and drinking using sodium adsorption ratio (SAR), sodium percentage (SSP), and comprehensive pollution index (F). The results show that the hydrochemical characteristics of the groundwater system are influenced by a combination of cation exchange, dissolution, and mixing processes, with deep aquifers exhibiting high Na+ and SO42− levels. The OGW mainly originates from the coal roof sandstone aquifers water (RSW) and 3rd limestone aquifer water (3LW). Additionally, the groundwater shows high alkalinity and salinity hazards, with irrigation water quality assessments falling into general and unsuitable water quality area. Moreover, the groundwater quality is below Class III standards, with the worst being Class V, rendering it unsuitable as a drinking water source. Untreated discharge of OGW to the surface can easily threaten human drinking water health. The study results are helpful in identifying and controlling groundwater pollution caused by coal mining, ensuring the safety and sustainable utilization of water resources in mining areas and surrounding regions. [ABSTRACT FROM AUTHOR]

In semi-arid northeastern Brazil, where water is scarce, rainforest refugia can be seen along the coastal relief, where the trade winds bring in humidity from the Atlantic Ocean, or further inland, at the Araripe plateau where water comes from aquifer resurgence. In order to reconstruct past changes in water resurgence and in their associated vegetation types, we analyzed pollen, charcoal, and trace elements from sediment cores collected in the permanent swamps created by the resurgences. Our high temporal resolution analyses show that the vegetation was more sparse and drier than today until 2700 cal yr BP. Between 2700 and 2000 cal yr BP, palm swamp and evergreen forest tree taxa started to expand, suggesting an increase in water resurgence. At 2000 cal yr BP, the moist forest with Mauritia expanded and fire activity changed from mixed to woody fuel particles. During the last 200 cal yr BP, a decrease in the palm tree Mauritia flexuosa, an expansion of Poaceae and an increase in macrocharcoal particles are attributed to an increase in anthropogenic activities in the Araripe Basin. The Late-Holocene climatic trend seen at Araripe mirrors that of eastern Brazil and has controlled the aquifer activity, including during the major droughts that affected the region. This is highly relevant for the application of public policies that rely on the aquifers of Araripe for the 21st century. [ABSTRACT FROM AUTHOR]

Clean water is a fundamental need for communities, sourced from both surface water (e.g., rivers, streams, springs) and groundwater (surface and deep aquifers). Groundwater dynamics are influenced by natural factors, including geology and geomorphology, which determine aquifer characteristics such as type, depth, thickness, and permeability. Geological structures influence groundwater flow direction, while lithology affects aquifer ion concentration and water quality. Surface morphology impacts groundwater table depth and movement patterns, with morphogenesis influencing permeability, porosity, and infiltration rates. This research investigates groundwater potential in Yalimo Regency, Mountainous Papua Province. The research aims to evaluate aquifer characteristics using regional geological and geomorphological assessments complemented by advanced mapping technology. The methodology integrates field mapping with geospatial analysis to identify and delineate groundwater resources. Results provide a detailed understanding of aquifer distribution, capacity, and potential for sustainable utilization. Conclusions emphasize the importance of combining traditional and technological approaches for accurate groundwater resource assessment, offering insights for effective water management in the region. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Geodesy & Geodynamics (1671-5942) is the property of Editorial Board Journal of Geodesy & Geodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An attempt has been made to comprehend the ground water quality and climate impacts of the Chennai River basin, which is aimed at its main socio-economic growth of the state of Tamil Nadu. The ground water samples collected from the study area were analyzed for its hydrogeochemical elements. The ground water quality and irrigation suitability were determined using several water quality assessment metrics. Ground water is extensively utilized for irrigation in the entire basin area for the past two decades, especially in the 38 over-exploited Firkas out of the 109 Firkas of the basin. It is inferred that the phreatic aquifer ground water quality is fresh in about 20%, as indicated by the EC value (< 750 µs/cm) at 25 °C. In about 63% of the ground water indicating the moderately fresh showing the EC varies between 751 and 2250 µs/cm at 25 °C, 11% of ground water exerted an EC ranging between 2251 and 3000 µs/cm at 25 °C indicating that the ground water is slightly mineralized, and in about 6% of groundwater, the EC is > 3000 µs/cm at 25 °C indicating that the ground water is highly mineralized. There were no water samples that exceeded the permissible limit of chloride either in phreatic aquifer or in fracture aquifer. The changes in rainfall frequency and atmospheric temperature affect the ground water movement and storage directly and indirectly. Similarly, the temperature data shows a positive relationship with the concentration of fluoride and nitrate ions in the water. [ABSTRACT FROM AUTHOR]

Subterranean structures such as aquifers and depleted gas reservoirs (DGRs) offer a scalable, high-pressure, secure, cost-efficient, and ecologically friendly means of hydrogen (H 2) storage. Underground H 2 storage (UHS) has emerged as a potential solution to alleviate the imbalance between the fluctuating renewable energy generation and the demand for a constant energy supply. Quantifying the recovery efficiency is of paramount importance in the effort toward large-scale UHS. In this numerical simulation study, we employed a high-resolution grid for the discretization of a synthetic (but realistic) heterogeneous anticline intended as a H 2 storage facility, and we assessed the H 2 recovery efficiency, and the purity of produced gas associated with UHS in natural reservoirs involving different pre-existing gases and their quantities. All of these studies included an initial phase of cushion gas injection, followed by 4 cycles of H 2 storage operations composed of injection-idle-withdrawal periods. The simulation results indicated that the H 2 round-trip recovery efficiency R H increased (a) with an increasing number of storage cycles, routinely exceeding 90% and providing evidence of a self-enhancement or self-optimization H 2 recovery mechanism and (b) with an increasing amount of pre-existing gas in the storage zone prior to the H 2 injections — at the end of the 4-cycle test, the highest R H is associated with a DGR with a pre-existing gas consisting of residual CH 4 and additional injected N 2 , and the lowest R H corresponds to an aquifer with no cushion gas. Conversely, the H 2 mass fraction of the produced gas F HQ (a) increased with an increasing number of storage cycles, but (b) decreased rapidly with an increasing amount of pre-existing gas. The presence of a pre-existing gas inevitably leads to severe contamination of the produced H 2 , which never exceeds 40% in the produced gas, can be as low as 4% in early cycles, and cannot be used as a H 2 fuel without gas separation. Aquifer storage without a cushion gas may exhibit the lowest H 2 recovery (about 75% in the long run), but yields practically pure H 2 that does not require further processing before use. A positive conclusion is that, under the conditions of this study, total H 2 losses (including H 2 escaping into the caprock, and inaccessible H 2 dissolved in the aqueous phase of the formation or remaining in the gas storage zone) are limited and manageable, indicating the technical feasibility of geologic H 2 storage. • Discussed the advantages and disadvantages of H 2 storage (UHS) in aquifers and depleted gas reservoirs (DGRs). • Explained reasons for the benefits of cushion gas (CG) or DGRs in UHS performance using material balance theory. • Injecting CG or adding cycles enhances the UHS performance by improving the overall compressibility of reservoirs. • Pre-existing gas improves the H 2 recovery efficiency but leads to the contamination of produced H 2. • Quantified the H 2 loss evolution during a UHS consisting of four injection-idle-withdrawal cycles. [ABSTRACT FROM AUTHOR]

Understanding near‐surface groundwater storage, flow patterns, surface and groundwater interactions in mining areas can assist in making mining more efficient and profitable. This is especially important in opencast mines affected by water inflows that may negatively affect production and increase mining costs. We map and characterize the near‐surface aquifer zones at the opencast site of Tharisa Minerals, located in the southwestern region of the Bushveld Complex (South Africa). The main goal is to infer pit water inflow at the mine site and determine how it may be better controlled. The Bushveld Complex hosts partially connected and unconfined alluvial, shallow‐weathered and crystalline bedrock aquifers, which are often connected by small‐scale permeable zones. Seismic refraction tomography, multichannel analysis of surface waves, electrical resistivity tomography and borehole data are used to map and understand the different aquifer zones in the vicinity of the mine, as well as infer their relation to water inflow in the mine pits. The geophysical surveys map the overburden, weathered bedrock aquifer zone, and the top of the crystalline aquifer rock zone reasonably well. They reveal extensive and deep weathering, and possible high hydraulic conductivity in the vicinity of the mine. The results provide a better understanding of the mine's near‐surface environment, which could be used to implement effective and targeted dewatering techniques, thus enabling better pit inflow water control to improve mine working conditions and production. [ABSTRACT FROM AUTHOR]

Abstract Effective monitoring of groundwater contamination is crucial to protect human livelihoods and ecosystems. This paper presents a machine learning-based approach to improve groundwater monitoring networks by providing predictions of groundwater contamination in space. The method is demonstrated through a practical application in Central Spain, where nitrate was used as a proxy for groundwater contamination. Predictive mapping identifies the spatial markers for groundwater contamination based on twenty-four predictor variables and a dataset of 213 existing monitoring boreholes. Tree-based algorithms found meaningful associations between the explanatory variables and known nitrate concentrations. Comparing the outcomes of the algorithms with the areas officially delineated as vulnerable to nitrate suggests that machine learning algorithms are able to predict groundwater contamination. The extra trees algorithm outperformed decision trees, random forest, gradient boosting, and AdaBoost classifiers, with an area under the curve score in excess of 0.88. Major predictors for groundwater contamination were depth to the water table, lithology, distance to rivers, and distance to livestock farms. Predictive mapping suggests that there are unmonitored regions to the northeast and to the southwest of Madrid’s metropolitan area that present similar markers to monitored regions known to be contaminated. These unmonitored areas should be prioritized in future attempts to improve the network. From a research perspective, the main conclusion of this work is that machine learning techniques can be used as a technique to automate the siting of monitoring boreholes. Practical applications should nevertheless be overseen by an expert eye to guarantee the quality of the outcomes.

Underground natural gas storage is an essential infrastructure for strategic reserves， emergency peak shaving， and national energy security. It is also one of the directions for optimizing the industrial layout of mature oilfields and promoting green and low-carbon transformation and development. The geological conditions of Shengli Oilfield are complex， with shallow gas reservoirs， small scale， scattered distribution， and abundant oil and water trap resources. However， it is difficult to evaluate the sealing property. In view of these characteristics， significant progress has been made in research related to gas storage since the “Thirteenth Five-Year Plan in 2016-2020” period. Different types of gas storage， such as loose sandstone gas reservoirs， gas cap oil reservoirs， and aquifers， have been studied and designed， and the first gas storage in abandoned water-flooded gas reservoirs in China， Y21 Gas Storage， has been built. Key technologies such as target screening and evaluation of gas storage in aquifers， injection and production operation optimization design of gas storage in aquifers， sealing evaluation of gas storage traps， and tracking evaluation of gas storage have been developed， which align with characteristics of Shengli Oilfield. At present， the construction of other types of gas storage still faces challenges such as limited data， small scale， poor efficiency， and difficulty in evaluating the dynamic sealing of traps. It is necessary to propose corresponding technical countermeasures and research directions in the site screening and evaluation of gas storage in oil reservoirs， the construction of gas storage in combination with scattered gas sand bodies， and the collaborative construction of gas storage in oil reservoirs with high water cut， to provide technical support for the large-scale construction and green development of gas storage in Shengli Oilfield.

Abstract Improving the living condition of residents of Palladan and Basawa community requires access to drinking water. The main objectives of this paper are to identify suitable groundwater zones for productive drilling and to assess groundwater mineralization in the coastal aquifers of the study area. Geographic Information Systems (GIS) and Analytical Hierarchy Process (AHP) were used in the methodology to generate the groundwater potential map. Slope, landcover/land use, lineament density, rainfall, soil cover and drainage density were taken into account to characterize the groundwater potential zones. Weights were assigned to the various parameters and their characteristics according to their impact on groundwater recharge. The groundwater potential map was classified into five zones namely: poor, fair, moderate, good, excellent. Based on the lineament density map, the distribution of these lineaments reveals the degree of porosity or permeability in each area and, consequently, its groundwater potential. Aeromagnetic data filtering permits the construction of a structural map that illustrates various geophysical lineaments that are known to be fault systems in the research area. These faults are the main routes via which groundwater seeps into the subsurface and granitoid-type magnetic rocks intrude into the basement. The research region is badly fractured/failed and made up of four lithologic units, including the aquifer layer (clayey sands in the cracked basement) with thicknesses varying from 12–55 m, according to the vertical electrical sounding (VES) applications. According to geoelectric cross-sections, the subsurface structures are made of granitic rocks that are surrounded by normal faults that trend both NW and NE. It is believed that groundwater flows into the hard rock aquifers in the studied locations through these notable geological features, such as faults and fractures. Two phenomena are responsible for the mineralization of water: a process of interaction between water and rock; and a process of salinization resulting from natural phenomena or anthropic activities. The present study could guide hydrogeological investigations and groundwater resource management planning in the study area.

Objective The analytical solution model is computationally efficient and widely used to estimate aquifer surges. Analytical solution models are computationally efficient but involving many assumptions, such as that the aquifer is homogeneous, the amount of water pumped is constant, while the head loss in the well is ignored; these models are often referred to as homogeneous models. In fact, these assumptions are often not met, resulting in nonnegligible errors in the results, especially for heterogeneous giant thick aquifers.Meanwhile, the homogeneous model cannot estimate the permeability coefficient and water inflow of the broken zone, which is not conducive to solve the water problem during tunnel construction. Methods In this study, two pumping tests were carried out on the Shengli Tunnel Project in Tianshan Mountain, Xinjiang. A geological model was established based on comprehensive logging data and borehole data; a heterogeneous numerical simulation method was used to quantitatively investigate the amount of groundwater inflow in bore holes. The parameters in the rate determination model of the observation data of the first pumping test were used, and the rationality of the model and the postrate parameters were verified by the observation data of the second pumping test. Results The permeability coefficients of the fracture zone, intact granite and relatively intact granite were inverted and were 0.000 93 m/d, 0.000 5 m/d and 0.000 3 m/d, respectively. The total water inflow and the water inflow of the fracture zone were predicted to be 14.80 m3/h and 10.46 m3/h, respectively, of which the water inflow of the broken zone accounted for 70.676% of the total water consumption. Conclusion Field observations revealed head loss in aan ultradeepbore hole during pumping test. The heterogeneous numerical simulation model can explain the ultradeep hole pumping test data better than the homogeneous model, and the total water inflow calculated by the homogeneous model is 18.67 m3/h, which overestimates the water inflow. During tunnel construction, the hydrodynamic parameters and water inflow obtained by the heterogeneous model are more reliable.

The open pit mining development begins with the opening of pits with the rock mass excavation and formation of slopes and berms for ore exploration. Knowledge about the geological conditions represents an important step in this process, since rock masses generally have heterogeneous characteristics and the presence of discon- tinuities can become an aggravating factor in the safety of operations. The characterization and classification of these discontinuities, as well as the identification of the groundwater in the rock mass, has a great importance to ensure the safety of operations during the mine's production process, in addition to ensure the effectiveness of its decommissioning process. The use of DC resistivity geophysical method has been increasing to characterization and identification lithological types and presence of water, since it is a non-invasive research tool with fast ability to obtain data. DC resistivity together with visual investigation methods, such as obtaining the discontinuities orientation and their alteration characteristics, provides important information for the characterization of the rock mass. Given this importance, the present work aimed to use DC resistivity to identify the presence of water and its correlation with lithology and rock mass structure in order to identify how these variables influence the occurrence of ruptures. To this end, two-dimensional resistivity sections were designed and related to visual inspection data and kinematic analyzes obtained from structural data of the rock mass. The integration of these results indicated that the ruptures present in the investigated mine slopes are related to zones whose predominant lithology is volcanic breccia with the presence of water in the subsurface. These ruptures compromise the stability of the slopes and consequently make the decommissioning mine process difficult.

Groundwater is one of the most important sources of freshwater, contributing significantly for drinking and other domestic activities around the world. However, its quality is deteriorating over time due to overexploitation and anthropogenic activities. Rib watershed is located in the Tana basin (Ethiopia), is intensively cultivated and urbanizing area. Therefore, this study attempted to assess groundwater vulnerability to pollution using the GIS-based Modified DRASTIC Model. The modified DRASTIC model was selected due to it incorporates both hydrogeological parameters and anthropogenic factors for assessment. The necessary data were collected from the field, and downloaded from websites and laboratory experiments (No3-). The results showed that more than 73.24% of the watershed is under medium to high vulnerability. Highly vulnerable areas of the watershed (22.48%) was confined to the Southern parts of the watershed (under built-up and cultivated areas). Based on single parameter sensitivity analysis, its vulnerability was highly influenced by aquifer media (24.1%), net recharge (21.75%), land use/land cover (15.1%), and depth of groundwater table (13.6%). The Modified drastic model was validated based on the observed data of nitrate concentration in groundwater. Based on the observed data of nitrate concentration, high-vulnerable areas were more contaminated than medium and low-vulnerable areas. The modified drastic index has a strong correlation with nitrate concentration with (r = 0.76) and (P < 0.043). Therefore, the result indicated that the area is vulnerable to contamination calling for appropriate groundwater management. Hence, this finding helps to plan and minimize future contamination of groundwater by considering its vulnerability before high-risk activities are allowed. [ABSTRACT FROM AUTHOR]

Brazilian mining ventures aged 30 years or older were studied, revealing historical oversights in environmental planning that have caused substantial environmental liabilities during active mining and decommissioning. Electrical resistivity tomography surveys were conducted in a decommissioning uranium mine in southeast Brazil. The results provided valuable insights into local hydrogeological dynamics, revealing the flow of acid mine drainage in two distinct systems: the porous waste rock pile and the fractured underlying crystalline basement. Geo-electrical sections displayed conductive anomalies indicating hydraulic connectivity between the waste rock pile and the underlying fractured aquifer through crystalline basement fractures. This connection was substantiated by sub-vertical zones of low electrical resistivity interpreted as groundwater influx from the porous system to the fractured aquifer. Consequently, the waste rock pile acted as a localized recharge zone for the regional aquifer, facilitating chemical exchanges between the two systems. Furthermore, the study successfully differentiated less impacted saturated zones (resistivity ≈80 Ω·m) from those associated with acid mine drainage (< 40 Ω·m). Preliminary investigations identified a complex fracture network in the study area, comprising two main fault systems with preferential NE and NW orientations, nearly orthogonal to each other. This fracture network demonstrated continuity, playing a fundamental role in sustaining flow within the local and regional drainage network. [ABSTRACT FROM AUTHOR]

Freshwater, vital for life and ecosystems, accounts for only 2.5% of Earth's water, and is primarily located in polar caps, underground reservoirs, and surface water. Its quality varies due to environmental interactions, especially in groundwater. Tenerife, located in the Canary Islands, Spain, relies mainly on underground aquifers and tunnels capturing 51.6 cubic hectometers annually. Ensuring safe drinking water is a global challenge due to health risks from poor water quality, including diseases and cancer. Fluoride, sodium, and potassium are essential for health, and are mainly derived from groundwater as fluoride ions (F−) and sodium and potassium cations (Na+, K+). However, excessive F−, Na+, and K+ in drinking water is harmful. The World Health Organization limits F− to 1.5 mg/L, Na+ to 8.70 meq/L, and K+ to 0.31 meq/L. Geological, climatic, and human factors control the presence and transport of F−, Na+, and K+ in groundwater. Seismic events can impact water quality, with long-term effects linked to aquifer structure and transient effects from gas and fluid expansion during earthquakes. This study was motivated by a 3.8 mbLg earthquake in Tenerife in 2012, which allowed its impact on groundwater quality, specifically F−, Na+, and K− concentrations, to be examined. Post-earthquake, F− levels alarmingly increased to 8.367 meq/L, while Na+ and K+ showed no significant changes. This research quantifies the influence of earthquakes on increasing F− levels and evaluates F− reduction during low seismic activity, emphasizing the importance of water management on volcanic islands. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

North Florida's karst springs are among the largest and most abundant in the world. Despite relatively stable spring discharges, flow reversals can episodically occur in some springs when river waters backflow into the aquifer during flood events. Reversals are normal features of the springs along the Suwanee River, but the changing incidence of these reversals in response to anthropogenic activities or climate change remains unclear and the mechanisms responsible for these reversals remain poorly described. Here we develop a reduced‐complexity hydrogeological model of the Suwannee River catchment to explore conditions needed to induce spring flow reversals. Our model demonstrates that reversals require two conditions: (a) a hydrogeological setting that combines an upstream catchment with rapid hydrological responses to meteorological drivers, which freely drains to a downstream catchment containing the karst aquifer (i.e., the spring‐fed river segment); and (b) meteorological conditions that create sufficient temporal variability in recharge. Given both conditions, recharge events can propagate from the upstream catchment and fill the downstream river segment faster than it can drain, causing river stage to rise above the aquifer head, resulting in temporary spring flow reversal (or bank storage). Our model accurately predicts significant post‐flood increases in spring flow as bank storage recedes, and using measured electrical conductivity at a major river‐adjacent spring we also quantify the enhancement of limestone dissolution (cave enlargement) due to reversal events. A comprehensive assessment of the incidence and duration of reversal events shows a predominant influence of climate and vegetation changes over that of groundwater pumping. Plain Language Summary: North Florida's karst springs are among the largest and most abundant in the world. Spring flow is very stable and usually into the main river, but reversals of flow direction may occur temporarily, such that water from the river enters the subsurface through the springs. This is a natural feature, but its causes and future behavior under climate change and human activities are poorly understood. In this work, we develop a simple model of the Suwannee River catchment that describes spring flow and reversals, showing that reversals require both appropriate geological as well as meteorological conditions. We also show that spring flow reversals contribute significantly to the limestone cave enlargement near the river, and that the future characteristics of reversal events are most dependent on climate and vegetation changes. Key Points: A reduced‐complexity model explains flow reversals in Florida karst springs due to fast discharge response from upstream surficial aquiferThe occurrence of reversals requires a certain hydrogeological setting and sufficient temporal variability in aquifer rechargeThe model also quantifies enhanced limestone dissolution rates (cave enlargement) near the river due to flow reversals [ABSTRACT FROM AUTHOR]

Located in Douala V (Cameroon), Makepé Missoké is a lowland area that is influenced by the Tongo Bassa and Ngongué rivers. The site has a closed dumpsite, that operated from the 1975's to 2003 for the disposal and storage of domestic waste produced in Douala. Geoelectric profiling (ERT) coupled with seismo-electric imaging was used to characterize the shallow aquifer of the Douala subbasin and map subsurface pollution. Fourteen geoelectrical profiles were deployed between June and August 2018 and March 2019. Along these lines, 49 sets of seismo-electric point data were collected in December 2021. A total of 118 wells drilled (2018) were used to obtain water level and topographic data. The aquifer geometry, hydraulic characteristics, permeability, lithology and leachate plume extent were determined. This survey enables us to visualize waste infiltration and migration within Makepé. The drilled wells indicate that the main lithologies observed are clay, sandy clay, sand, clayey sand and gravel. The leachate plume observed after processing the electric profiles had a resistivity signature of < 10 Ωιτι, and high electrical conductivity are observed in some wells. The leachate migrates within the subsurface along a northwest-southwest trend, where ground water pollution is observed due to leachate infiltration. This infiltration resulted in poor water quality indices in some collected samples. Such pollution is common in unconfined aquifers (< 50 m) due to the absence of a confining layer at the landfill. An increase in resistivity values with depth toward the northeast direction indicates progressive vertical dilution during leachate mineralization. This study integrated geoelectric and seismo-electric tomography with basic water chemistry analysis to effectively characterize the groundwater within the phreatic Quaternary/Mio-Pliocene aquifers of the Douala basin. [ABSTRACT FROM AUTHOR]

Knowledge of aquifer parameters is essential for the management of groundwater resources. Parameters such as porosity and specific yield are among the basic features used to describe the hydrogeological conditions of a region. This study compares the electromagnetic method with geoelectric sounding. The data collection was carried out through a field survey and is used to study and estimate the values of porosity and specific yield of the karst aquifer that feeds five springs: Famaseb (Sp1), Faresban (Sp2), Giyan (Sp3), Ghale Baroodab (Sp4), and Gonbad kabood (Sp5). All these springs are located in the Nahavand Plain, Hamadan Province, west of Iran. Fifteen (15) soundings were obtained upstream of each spring and were used to analyze the results, quantitative and qualitative interpretation of geoelectrical data, logs of subsurface layers, and ranges of true resistivities and their electromagnetic frequencies were determined. The value of the true resistivity was calculated for the saturated and unsaturated layer of each spring, the results were compared with the electromagnetic frequencies, which showed that the results of the two methods used were almost similar. Porosity and specific yield were calculated using Archie's law. It is found that the Faresban spring (Sp2) has maximum porosity of 55% and a specific yield of 0.48 and in contrast to the lowest value of parameters mentioned in the Ghale Baroodab spring (Sp3, porosity 26% and specific yield 0.18). All the estimated values are compatible with the discharge of springs measured in the field and consistent with the geological conditions of the study area. [ABSTRACT FROM AUTHOR]

Groundwater level tidal analysis is a powerful technique to monitor aquifer's permeability and hence its change over time. Earthquakes are known to affect aquifer's properties, in their vicinity through static stress changes but also further away through dynamic stresses. Most often changes are in the form of permeability increases, but sometimes decreases; the changes can be either permanent or transient. These observations are relatively well documented but the physical processes behind these changes are not well understood. By combining solid‐earth and barometric tidal groundwater level responses in a borehole in a coherent poroelastic theoretical framework, and a bi‐layer hydrogeological model, we recover a 15 years‐long time series evolution of aquifer transmissivity and shear modulus. This study showcases the full potential of the tidal analysis method, coupling pore pressure diffusion and rock deformation, at the frontier of hydrogeology and rock physics. This unprecedented measurement of permeability and shear modulus evolution by tidal analysis reveals, during interseismic period, high sensitivity of this shallow aquifer to effective stress, and thus to pore pressure. Thanks to additional finite element simulation of seismic wave propagation, we explore the different mechanisms affecting permeability and shear modulus in the studied fractured andesite aquifer. This study confirms the predominant role of seismic dynamic stresses, and more precisely of dynamic shear stresses, in the change of permeability following an earthquake. Plain Language Summary: Tidal oscillations of groundwater level, observable in boreholes all around the world, are information‐rich signals for hydrogeologist to infer the properties of surrounding aquifers, and how they evolve over time. Most importantly, it allows to monitor aquifer permeability and how it evolves under the influence of earthquakes, especially through static stresses changes or seismic wave propagation. Here we push the limits of what tidal analysis can reveal by also retrieving the shear modulus of the studied aquifer. This new observable, combined with the computation of regional earthquakes stresses, allows us to understand better how aquifer properties are modified by earthquakes. The analysis reveals first that dynamic shear stresses are the most probable cause of permeability changes, and second that the sensitivity of our fractured aquifer permeability to pore pressure is high. Key Points: The 15‐years' time series of permeability and shear modulus of the aquifer is deduced from the analysis of solid earth and barometric tidesCo‐seismic irreversible changes of fractured aquifer permeability are induced by earthquakes dynamic shear stressesInterseismic permeability variations of the aquifer are controlled by pore pressure, that is, the hydraulic head [ABSTRACT FROM AUTHOR]

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are widespread groundwater contaminants and are present in over 7000 drinking water wells near a North Carolina (NC) PFAS plant (Chemours). To understand options available to affected residents, we used new and previously existing water quality data to investigate deeper aquifers as alternate drinking water supplies and compared the regulatory responses near Chemours and three other PFAS production facilities with nearby contaminated wells. Data from >100 wells show that GenX concentrations decrease with increasing depth through the four aquifers in the study area: surficial, Black Creek, Upper Cape Fear, and bedrock. This illustrates the extent of vertical PFAS penetration through the aquifer sequence following roughly 40 years of atmospheric emissions. Detailed data on 143 water quality parameters in nine deep wells (two Upper Cape Fear, seven bedrock) revealed only eight exceedances of drinking water standards (one each for arsenic, perfluorooctanoic acid [PFOA], iron, chloride, and gross alpha, and three for manganese) and nine exceedances of health advisories (all for sodium). Regulatory responses to PFAS contamination of wells in four states included mention of deeper wells as an alternate water source only for nonresidential users in NC and residential users in Vermont. The bedrock aquifer is currently used by some residents and may be a viable alternative to shallower groundwater, though arsenic treatment may be beneficial at some deep wells and long‐term sustainability of the aquifer should be evaluated. Practitioner Points: GenX concentrations decreased with increasing depth in four aquifers near a PFAS plant.A few exceedances of drinking water standards and health advisories were found in deep bedrock wells.New bedrock wells could be part of the response to PFAS issues in shallower wells.In the long term, deep bedrock wells might be a less expensive option for some residents. [ABSTRACT FROM AUTHOR]

The subsurface aquifer zone is significant groundwater source, hence this paper investigates subsurface aquifer zones in Kaiama Community, Kolokuma/Opokuma local government area of Bayelsa State, Nigeria with the purpose of exploring groundwater using geoelectric sounding (GES) surveys. Five survey points were examined using Schlumberger electrode configuration and deploying SAS 1000 Terrameter set, with data processed with IPI2win software. Each survey station revealed distinct layers with varying resistivity, depth, and lithology, offering crucial insights into subsurface features and aquifer systems. For GES 1, indicates five layers showing their resistivity values with respect to depth as 400.7Om with a depth of 0.6m as top soil, 16.14Om-51.01Om with a depth of 3.219-7.4356m as clay and layer 6 expressed as 19527Om with a depth of 30.01m as coarse sand and aquiferous layer. GES 2 along Kaiama's East-West Road delineated four layers with resistivity value of 467.2Om with a dpth of 1.264m as top soil, 54.5Om with a depth of 18.8m as clay and 2738Om with a depth of 40.01m as coarse sand, which also indicates as a potential aquiferous layer. GES 3 at R.PM School 1 Field identified five layers, highlighting 121.1Om with a depth of 0.6m as top soil, 16.67Om-5795Om with depth of 40.2m as clay with a resistivity potential of 237.7Om with a depth of 60.01m as medium sand and subsurface aquiferous layer. GES 4 at Kaiama Grammar School field revealed six layers, with resistivity value of 327.9Om with adepth of 0.6m as top soil, 6.383-20.51Om with depth of 3.219-7.456m as clay and 800Om with depth of 17.27m as medium sand and resistivity of 91599Om with depth of 30.22m as coarse sand medium sand indicating potential aquifer zones. GES 5 at Isokiwari Compound Kaiama showcased five layers: resistivity of 43.7Om with depth of 0.6m as top soil, 300.5Om-417.8Om with depth of 1.39-7,521m as medium sand, 65.17Om-112.5Om with depth of 17.33-40.07m as clay. The findings provide valuable information for groundwater management and resource exploration in the region, emphasizing the significance of understanding subsurface geology for sustainable water access. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Saltwater intrusion in a coastal region is one of the major issues facing the agricultural, domestic, and industrial sectors. Groundwater withdrawal for an increasing population and agricultural and industrial demands are the main reasons for saltwater intrusion into coastal aquifers. Saltwater intrusion into freshwater aquifers directly affects a population's health, economy, and social development. This study explores an innovative approach to modeling saltwater intrusion into freshwater using a prey–predator model. Freshwater is analogized as the prey and saltwater as the predator, providing a unique perspective on understanding this phenomenon. The present model was formulated using a balance of freshwater and saltwater and is applicable to coastal aquifers. An amount of freshwater withdrawal such that the volume of saltwater does not produce adverse impacts is predicted graphically. Based on a certain simulation, the current model suggests that if the withdrawal rate drops to 50%, freshwater is projected to surpass saltwater dominance for about 90 years. The model has been validated through a benchmark saltwater intrusion problem. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

GROUNDWATER is the major source of irrigation and domestic water use in the East El-Owainat region since it is accessible and pollutant-free. The measured qualitative groundwater variables (salinity, alkalinity, total dissolved salts, total hardness and soluble ions), irrigation indexes and Canadian water quality index (CCME-WQI) were calculated to estimate water quality. Piper's trilinear diagram showed that over 85% of the total samples exhibit Na-Cl facies, indicating that the mineral structure of the water reservoir has a substantial effect on the chemical characteristics of aquifers. The tested groundwater samples revealed that 59.68% of the salt assemblage consisted of NaCl, Na2SO4, MgSO4, and Ca (HCO3)2, illustrating the leaching effects and dissolving evaporating deposits as well as the intermediate stages of chemical evolution. About 39% of the total samples had Fe concentrations higher than what is acceptable for human consumption. The US Salinity Diagram revealed that the bulk of the tested samples belong to the C3S1 group, which defines a high salinity with a low Na type. According to CCME-WQI, 80 and 97% of groundwater samples are acceptable for drinking and excellent for irrigation, respectively. A factor analysis suggests that ion exchange and groundwater-rock exchanges, all of which are connected to the natural water source, have a favorable impact on the water quality. Groundwater quality based on the CCME-WQI index remains suitable for human and cultivation purposes. For ecosystem safety, groundwater quality must be monitored regularly. [ABSTRACT FROM AUTHOR]

Determining the degree of an aquifer’s susceptibility to pollutants is an important tool for policy planning in subterranean water administration and conservation. In this work, subterranean water vulnerability was appraised with the use of DRASTIC methodology, which employs seven parameters: depth to groundwater (D); net groundwater recharge (R); aquifer media (A); soil media (S); topography (T); influence of vadose zone (I); and hydraulic conductivity (C). Different ratings were given to each parameter based on the hydro-geological and geo-electrical information obtained from the study area. Geo-electrostratigraphic data was acquired with vertical electrical soundings and electrical resistivity tomography surveys. The results demonstrated the existence of geoelectrical layers with variable resistivities ranging from high to low, with variable curve types. Longitudinal conductance measures indicated moderate subterranean water protective capacity. Analysis of DRASTIC vulnerability indices showed that the aquifer indicated moderate to high vulnerability to contamination. Vulnerability maps were generated to indicate locations of high vulnerability, the goal being to prevent indiscriminate haphazard and wildcat abstraction of groundwater in such locations. The quality category index (QCI) generated for the DRASTIC model indicated that underground water susceptivity is dependent on all 7 parameters employed in the model, with the most critical determinants being the depth to aquifer (D), net recharge (R), aquifer media (A), and impact of the vadose zone (I). The work recommends that anthropogenic activities that could contaminate groundwater resource be halted as the resource is indicated by DRASTIC models as being vulnerable.

It is indicated that surface water resources under the conditions of growing technogenesis and the consequences of military actions (military, geochemical pollution of catchment landscapes, destruction of treatment facilities, etc.) are classified as polluted and dirty (IV, V quality class). Underground water resources of Ukraine amount to 22.5 billion m3, of which up to 70% are protected or conditionally protected artesian waters of drinking quality, the transition to the use of which determines the relevance of the article. The purpose of the article is to analyze the potential factors of regional development of dangerous geofiltration processes of water use in underground water basins of Ukraine. The scientific novelty of the article lies in the assessment of the degree of influence of the complex of dangerous lithodynamic processes (HLDP), which have a hydrogeofiltration origin, on the qualitative characteristics of groundwater, the stability of the upper part of the rock massif, and the safe operation of water intake facilities. Practical significance. It is shown that with any scheme of depression funnel formation, the diffusion-convective movement of salts and microcomponents from the pore solutions of the poorly permeable (separating) layer is a stable spatio-temporal factor affecting the hydrogeochemical composition of water in operational aquifers. It has been proven that the hydrogeochemical evolution of the composition of water at most water intakes in Ukraine requires changes in approaches to the justification of well location schemes and the amount of allowable decreases in levels in operational horizons. It is estimated that engineering-geotechnically significant filtration compression of the aquifer occurs when the level drops by tens of meters or more. The results of spatio-temporal monitoring of filtration and compression subsidence of the earth's surface in the areas of depression funnels of water intakes and drainage and drainage systems of quarries and mines on the territory of Ukraine indicate that, in general, the amount of subsidence of the earth's surface is correlated with a decrease in the level in the operational aquifer, and in in most cases it is 1.0-2.5% of its value. It has been established that the subsidence of the earth's surface in the zones of depressions of underground water intakes is often accompanied by flooding and waterlogging of the territory, deformations of buildings and structures of engineering communications. It is stated that the active role in the development of the suffusion process during the operation of water intakes and drainage systems is played by the interlayering of fissured (crack-karst) sandy, multi-grained aquifers. This contributes to the formation of zones of increased hydraulic gradients and accelerated movement of hydrogeofiltration flow at the contacts of cracked and sand-dust layers and, as a result, activation of suffusion along the cracks. Calculations prove that the dangerous development of the suffusion process in the near-filter zone of the production well on the aquifer in multi-grained sands reaches 10-15 m. In the central zone of the depression funnel of a group or linear water intake, under the condition of the interaction of local well depressions, the distance of the development of suffusion deformations of the earth's surface increases significantly (up to 3-5 times) and worsens the engineering and geotechnical stability of production wells, pumping equipment, etc.

Abstract Groundwater is vital for sustainable development, and this study addresses potable water challenges in Shango, North-Central Nigeria. The main goal is to identify optimal sites for new wells and boreholes, utilizing geological and geo-electrical attributes from existing boreholes and wells. Vertical Electrical Sounding (VES) assessed groundwater potential, aquifer protection, and overburden corrosivity. Sixteen VES stations were probed using Schlumberger array with a maximum current electrode spacing (AB/2) of 200 m using a resistivity meter. The data were interpreted using an automatic computer inversion program, IPI2WIN. The VES results revealed five subsurface geo-electric units, with depths to the aquifer ranging from 58 to 68 m, each exhibiting distinct characteristics contributing to the lithological variability of the research area. Hydraulic conductivity ranged from 0.465 to 0.534 m/day, while transmissivity varied from 9.589 m2/day to 26.029 m2/day across different VES points. Regions exhibiting thick layers and low resistivity values indicate high longitudinal conductivity. Furthermore, areas with low protective capacity are susceptible to the risks of pollution and contamination stemming from leaks and waste sites. The study revealed that all VES points are in practically non-corrosive zones, making them suitable for burying underground tanks with extremely low deterioration rates. Based on geoelectrical characteristics, the study area was divided into three groundwater potential zones: low, medium, and high. These findings provide valuable insights into the groundwater potential and protective capacity of the Shango area, while emphasizing on the vulnerability of these regions and highlighting the pressing need for appropriate preventive measures to safeguard against potential environmental hazards.

Revealing the contribution of each of the climatic and human factors can help the management of water resources. Firstly, trend analysis and change‐point tests were performed to determine the status of the parameters affecting the groundwater resources of the Mahidasht aquifer during the period from 1981 to 2019 by using statistical methods and the Pettitt test. The GMS model was calibrated as a tool to simulate the Mahidasht aquifer system. After determining the change point, modeling of the groundwater level before and after the change point was done using the GMS model. By removing the effect of human factors in the model, the contribution of the effects of climate variability and human activities on groundwater was obtained. The results showed that there was no significant trend in annual rainfall, but the annual runoff has a significantly decreasing trend at the confidence level of 99%, and the trend of the groundwater level is also significantly decreasing at the confidence level of 99%. Pettitt change point test showed precipitation without a change point, but the runoff in 1998 and the groundwater level in 2001 had a change point. Finally, the modeling of the aquifer showed that the contribution of human activities in the reduction of the groundwater level of the Mahidasht aquifer was 78 and climate variability is 22%.

The Bekaa Plain in Lebanon, is a major agricultural region known for its fertile soil and extensive crops cultivation using groundwater resources which is recently became under stress due to population growth, urbanization, and climate change. The main aim of this study is to investigate the rate of groundwater recharge (GwR) into this region using APLIS Model which principally depends on altitude, slope, lithology, infiltration, and soil type. Using GIS-based for a multicriteria mapping approach, in this study additional factors were added to the model, by incorporating rainfall rates, stream density, and fracture density. Results revealed various recharge potential area in the Bekaa Plain, with 52 % classified as high to very high GwR zones, equivalent to approximately 42.5 % of precipitated water, which is a testament to the exceptional capacity of the region to replenish groundwater aquifers. The geographic distribution of GwR categories primarily depends on altitude and lithological characteristics. The exceptional GwR potential of the Bekaa Plain holds immense promise for mitigating water scarcity, fostering agricultural productivity, and ensuring the socioeconomic well-being of communities reliant on groundwater resources.

Due to the increasing world population and environmental considerations, there has been a tremendous interest in alternative energy sources. Hydrogen plays a major role as an energy carrier due to its environmentally benign nature. The combustion of hydrogen releases water vapor while it also has a vast industrial application in aerospace, pharmaceutical, and metallurgical industries. Although promising, hydrogen faces storage challenges. Underground hydrogen storage (UHS) presents a promising method of safely storing hydrogen. The selection of the appropriate cushion gas for UHS is a critical aspect of ensuring the safety, efficiency, and reliability of the storage system. Cushion gas plays a pivotal role in maintaining the necessary pressure within the storage reservoir, thereby enabling consistent injection and withdrawal rates of hydrogen. One of the key functions of the cushion gas is to act as a buffer, ensuring that the storage pressure remains within the desired range despite fluctuations in hydrogen demand or supply. This is achieved by alternately expanding and compressing the cushion gas during the injection and withdrawal cycles, thereby effectively regulating the overall pressure dynamics within the storage facility. Furthermore, the choice of cushion gas can have significant implications on the performance and long-term stability of the UHS system. Factors such as compatibility with hydrogen, cost-effectiveness, availability, and environmental impact must be carefully considered when selecting the most suitable cushion gas. The present study provides a comprehensive review of different types of cushion gases commonly used in UHS, including nitrogen, methane, and carbon dioxide. By examining the advantages, limitations, and practical considerations associated with each option, the study aims to offer valuable insights into optimizing the performance and reliability of UHS systems. Ultimately, the successful implementation of UHS hinges not only on technological innovation but also on strategic decisions regarding cushion gas selection and management. By addressing these challenges proactively, stakeholders can unlock the full potential of hydrogen as a clean and sustainable energy carrier, thereby contributing to the global transition towards a low-carbon future.

Geo-electro stratigraphic assessments of aquifer potentiality, protectivity, and pliable level of vulnerability within a coastal milieu were undertaken with geo-electrical technology. The vertical electrical soundings were undertaken at 20 locations and the 2D electrical resistivity tomography surveys were undertaken at five locations within the study area. Results obtained from these geo-electrical surveys coupled with hydro-geophysical investigations within the area indicated the presence of four geo-electric layers: motley topsoil, sandy clay, fine sand, and coarse sand. The geo-stratigraphic data assessed groundwater potentiality, protectivity, and vulnerability to contamination with measures of transverse resistance, hydraulic conductivity, transmissivity, hydraulic diffusivity, aquifer storativity, and longitudinal conductance. Geo-hydraulic characterization indicated mean aquifer resistivity of 554.6 Ωm, mean aquifer conductivity of 0.0004 S/m, mean longitudinal conductance of 0.67 Ω−1, mean transverse resistance of 5601.7 Ωm2, mean hydraulic conductivity of 3.5 m/day, mean transmissivity of 283 m2/day, mean storativity of 0.0002, and mean hydraulic diffusivity of 1 × 105 m2/day. The results indicated that the region's groundwater potential ranged from medium to high. Longitudinal conductance values indicated that the aquifer protective capacity ranged from moderate to poor. Geo-electrical technology was therefore found to be an effective methodology for delineating aquifer potentiality, protectivity, and vulnerability within the vulnerable coastal aquifer system. HIGHLIGHTS Geo-electrical technology was employed to determine transverse resistance, hydraulic conductivity, transmissivity, hydraulic diffusivity, aquifer storativity, and longitudinal conductance.; Results indicated that groundwater potential ranged from medium to high.; Aquifer protective capacity ranged from moderate to poor.; The aquifer has a high vulnerability to contamination.; This aquifer system has been characterized.;

The stabilization of groundwater resources in excellent quality is crucial for both the environment and human societies. To examine the contaminant concentration pattern of infinite and semi-infinite aquifers, mathematical models provide accurate descriptions. The two-dimensional model for a semi-infinite heterogeneous porous medium with temporally dependent and space-dependent (degenerate form) dispersion coefficients for longitudinal and transverse directions is derived in this study. The Laplace Integral Transform Techniques (LITT) is used to find analytical solutions. The dispersion coefficient is considered the square of the velocity which represents the seasonal variation of the year in coastal/tropical regions. To demonstrate the solutions, the findings are presented graphically. Figures are drawn for different times for a function and discussed in the result and discussion section. It is also concluded that a two-dimensional model is more useful than a one-dimensional model for assessing aquifer contamination.

Kelurahan Sukarame di sebelah selatan kampus ITERA memiliki lahan kosong yang potensial untuk pembangunan perumahan, rumah kontrakan, dan industri. Namun, eksplorasi air tanah di daerah ini kurang banyak dilakukan, sehingga memerlukan perhatian khusus untuk dilakukan eksplorasi air tanah untuk kebutuhan pembangunan dan penduduk sekitar. Langkah penting dalam menghadapi masalah ini adalah mengetahui keberadaan akuifer untuk memperoleh sumber air tanah yang memadai. Identifikasi akuifer dilakukan menggunakan metode Vertical Electrical Sounding (VES). Dengan studi ini akan dapat menentukan jenis litologi bawah permukaan, mengetahui kedalaman lapisan akuifer dan dapat juga mengidentifikasi jenis akuifernya. Pengukuran dilakukan dengan 11 titik sounding menggunakan konfigurasi Schlumberger dengan AB/2 maksimal 100 meter. Berdasarkan nilai resistivitas, kawasan tersebut tersusun dari batu lempung tufan dengan nilai resistivitas 20 Ωm, batu pasir tufan dengan rentang nilai resistivitas antara 20-80 Ωm, dan batu tuf dengan nilai resistivitas 80 Ωm. Lapisan batu pasir tufan diduga merupakan lapisan dari akuifer. Pada daerah penelitian terdapat dua jenis akuifer yaitu akuifer bebas yang ditemukan pada kedalaman 3 meter dan akuifer semi-tertekan pada kedalaman 5 meter.