Aquifer Characteristics Research Articles

Impact of Long Well Screens on Monitoring of the Freshwater-Saltwater Transition Zone.

Deep monitoring wells with long screens crossing the transition zone between freshwater and saltwater are often used in coastal areas to characterize fresh groundwater resources and the depth of saline groundwater. However, past studies have demonstrated that long-screen wells can lead to biased observations of the transition zone, since vertical flow within the borehole can modify the shape and elevation of the transition zone in and around the borehole compared to undisturbed conditions without a well. Here, field observations and variable-density numerical flow simulations are used to evaluate, under natural flow conditions, how the installation of long-screen wells can provide time-varying biased observations of the freshwater-saltwater transition zone, and how various aquifer and well parameters affect the magnitude of these biases. Results show that long-screen wells can lead to a more dispersed interface, an upward displacement of the transition zone of between 5 and 10 m, and a salinity decrease in the saltwater portion of the well on the order of 10 to 15 g/L. The perturbations take up to 5 years to fully develop and stabilize. The degree of displacement depends on the screen diameter, screen length, aquifer anisotropy, and hydraulic conductivity, whereas the displacement is independent of the distance of the well from the coast. This analysis provides insight into which well and aquifer characteristics increase the risk of obtaining biased observations in long-screen wells, and provides orders of magnitude for these biases.

Understanding complex volcanic hydrosystems using a multi-tracer approach.

Climate change affects groundwater availability and residence times, necessitating a thorough understanding of aquifer characteristics to define sustainable yields, particularly in regions where water is heavily exploited. This study focuses on the Volvic volcanic aquifer (Chaîne des Puys, France), where groundwater recharge has decreased due to climate change, raising concerns about water use sustainability. To address these challenges, this work proposes a multi-tracer approach, based on hydrogeological monitoring, including the estimation of groundwater ages, major elements chemistry and water stable isotopes to better characterise this resource decrease and more peculiarly its origin and its impact on the environment that has never been addressed. Relative fractions of ancient and modern water contributions (up to 20%) to the aquifer have been thus estimated as well as the apparent ages of groundwaters (34years). We highlight the complementarity of tracers used, allowing a better definition of recharge sources and transit times of groundwaters within the aquifer. These results led to the proposal of a hydrogeological conceptual model, highlighting a bi-modal recharge, distinguishing between a long-term recharge upon 30years, supplemented by a recent component (≃ 1year) related to annual precipitation. This study provides valuable information on groundwater circulation and the response of volcanic aquifers systems to climate change, while highlighting the importance of assessing residence times. By addressing the challenges posed by systems with contrasting permeability and recharge gradients, it improves understanding of volcanic hydrology and provides a basis for the development of (numerical) hydrological models to assess the impacts of global change.

Aquifer characterization and evaluation of groundwater potential zones in the frontal part of the Himalayas using electrical resistivity tomography technique

Aquifer characterization and evaluation of groundwater potential zones in the frontal part of the Himalayas using electrical resistivity tomography technique

Aquifer characterization using geophysical borehole-logging and hydrochemical techniques—a case study from Lahore, Pakistan

Aquifer characterization using geophysical borehole-logging and hydrochemical techniques—a case study from Lahore, Pakistan

Application of Pumping Tests to Estimate Hydraulic Parameters of Volcanic Aquifers in Lake Tana Basin, Ethiopia

The purpose of this study was to enhance the understanding and sustainable groundwater management of volcanic aquifer systems by estimating key hydrogeological parameters. The transmissivity of a volcanic aquifer system was estimated using analytical solutions based on 68 constant rate and recovery data sets collected from various sources. A combination of hydro-lithostratigraphy and diagnostic plots was employed to identify the aquifer types and flow conditions, which facilitated model selection. Transmissivity of the confined aquifer was modeled using both Theis and Cooper–Jacob methods, with the Theis residual drawdown solution utilized for estimation. For the unconfined aquifer, the Neuman method was used, and the Hantush/Jacob method was employed for leaky aquifers. The results showed that the transmissivity of the Tertiary basalt varied from 0.38 m2/d to 860 m2/d, while the Quaternary aquifer system ranged from 2.33 m2/d to 1.8 × 104 m2/d, indicating an increase in transmissivity with younger volcanic flows. Specific capacity (SC) was estimated for 74 wells and the values ranged from 0.62 to 5860 m2/d. This wide variation of specific capacity and transmissivity showed significant heterogeneity within the volcanic aquifers. This study introduces the innovative application of derivative diagnostic plots in groundwater research, offering an efficient approach for analyzing and interpreting pumping test data to characterize aquifer systems in various hydrogeologic units. This study focuses on aquifer characterization in hard rock formation, demonstrating methods that can be applied to similar geological environments globally. For the Blue Nile basin in general and for the Lake Tana basin in particular, the study result of aquifer characterization will contribute to exploration, development, and improved groundwater management in the region.

Enrichment mechanism and probabilistic health risk assessment of high-fluoride groundwater in Gaomi City, China.

Fluoride (F) is the most important inorganic pollutant in groundwater that affects human health, and analyzing the causes of high-fluoride groundwater is a prerequisite for protecting the health of residents. To comprehensively understand the enrichment characteristics of groundwater in the high-fluoride areas, this study systematically investigated the concentrations of fluoride in Gaomi City, a typical study area in the Jiaolai Plain and explored the spatiotemporal distribution patterns, enrichment mechanisms, and the probabilistic health risk associated with F-. The results indicate that there is serious fluorine pollution in groundwater, which is mainly concentrated in the alluvial plain in the north and affected by topographical and aquifer characteristics. Favorable runoff conditions effectively improve the fluoride status of shallow groundwater on both sides of rivers and in hilly areas. Hydrogeochemical methods reveal the mechanism of fluoride enrichment. The relative contributions rates of different hydrogeochemical processes to the fluoride enrichment are as follows: dissolution and precipitation (39.02%) > cation exchange (25.25%) > competitive adsorption (19.48%) > seawater intrusion (3.14%) > evaporative and concentration (1.99%). Health risk assessment based on Monte Carlo simulation shows that health risk susceptibilities of different populations are infants (76.07%), children (66.59%), teenagers (44.54%), and adults (5.68%), respectively. In addition, targeted management suggestions are put forward regarding the enrichment mechanisms of fluoride in groundwater and its impact on health. These findings have significant implications for controlling regional diffuse F- contamination in groundwater, protecting public health, and promoting social development in regions with a high risk of groundwater fluoride contamination.

Geoelectrical assessment of groundwater potential and aquifer characteristics in the west region of Cameroon

Geoelectrical assessment of groundwater potential and aquifer characteristics in the west region of Cameroon

MASTER RECESSION CURVE VISUALIZATION USING SEVEN BASEFLOW RECESSION MODELS IN PAIRED WATERSHEDS

River flow recession analysis plays a crucial role in understanding how watersheds release water during dry periods. Consequently, modeling baseflow recession is closely related to the characteristics of unconfined aquifers, storage behavior, and the discharge properties of the watershed. While several theories exist on modeling recession curves, limited research has compared different approaches regarding baseflow recession characteristics. This study aims to model seven baseflow recession equations in paired watersheds in Ambon City. The research methodology involves calibrating seven baseflow recession models using the Recession Curve (RC) 4.0 Hydro Office software. The tested models include Linear Reservoir, Exponential Reservoir, Double Exponential Horton, Dupuit-Boussinesq Aquifer Storage, Depression Storage, Turbulent Flow Model, and Hyperbolic Function Model. The calibration results yield optimal combinations of recession parameters. The parameterization order from highest to lowest is as follows: Depression Storage, followed by the Hyperbolic Function, Exponential Reservoir, Turbulent Flow Model, Double Exponential Horton, Linear Reservoir, and Dupuit-Boussinesq Aquifer Storage. Quantifying baseflow recession constants and coefficients is essential for understanding baseflow behavior. Visualizing the slope of the Recession Curve (MRC) reveals that models with high recession constants tend to have gradual MRCs, while low recession constants result in steep MRCs. The MRC slope further describes the relationship between storage conditions and discharge from the watershed. The advantage of creating MRCs from discontinuous recession segments lies in their ability to appropriately describe the MRC process and provide quantitative parameters relevant to drainage mechanisms. MRCs also serve as an optimal automated computational tool.

EDITORIAL

Greetings to the Readers of Jurnal Teknosains!We are delighted to present the latest edition of Jurnal Teknosains, Volume 14, Number 1, December 2024. This issue highlights groundbreaking contributions in the realms of technology and science, reflecting our dedication to fostering interdisciplinary insights into the challenges and opportunities of our rapidly evolving world. One of the central themes in this edition is the intricate interaction between humans and their environment. Notably, the study on visualizing streamflow recession curves demonstrates how mathematical modeling serves as a critical tool in water resource management. Employing multimodel approaches for baseflow recession analysis, this research underscores the importance of accurate data in understanding aquifer characteristics and water storage capacities on both local and global scales. In the domain of healthcare technology, innovation in enhancing the biocompatibility of acrylic materials with natural fibers takes center stage. The incorporation of bio-based fibers, such as banana fronds, offers a sustainable and biologically safer alternative while significantly improving material performance. This promising development addresses future demands for environmentally friendly and safe materials.

Equity Assessment of Groundwater Vulnerability and Risk in Drinking Water Supplies in Arid Regions

Groundwater is a vital drinking water source, especially in arid regions, sustaining both urban and rural populations. Its quality is influenced by natural (hydrogeological) and human-driven (demographic, policy) factors, which may pose significant public health risks, especially for communities relying on unregulated water supplies. This study addresses critical gaps by examining groundwater vulnerability and contamination disparities, emphasizing their implications for public health and equitable resource management. It analyzes the impact of socio-hydrogeological factors on arsenic and nitrate levels in groundwater-supplied systems in Arizona, U.S. Methods include spatial analysis, ANOVA, multivariate regression, and cluster analysis. Significant disparities in arsenic and nitrate contamination, including exceedances of regulatory limits, were observed across supply types, aquifer characteristics, jurisdictional oversights, and groundwater management areas. Domestic wells and community water systems showed distinct contamination risks. Groundwater vulnerability was influenced by geological differences (karst vs. alluvial aquifers) and regulatory oversight, with Tribal and State systems facing unique challenges and resource needs. Socioeconomic disparities were evident, with minority communities, institutional facilities, rural areas, and specific housing types disproportionately exposed to higher contaminant levels. These findings unveil the intersection of race, socioeconomic status, and public health risks, offering an adaptable framework for addressing similar groundwater challenges in arid and semi-arid regions globally. This study is innovative in its focus on policy distinctions between private and regulated wells, karst and alluvial aquifers, and State and Tribal jurisdictions. It emphasizes the need for targeted vulnerability assessments and remediation strategies that integrate geological, hydrological, and regulatory factors to address risk disparities in vulnerable communities. These environmental inequities underscore the urgent need for stronger regulations and strategic resource allocation to support marginalized communities. The study recommends enhancing monitoring protocols, prioritizing resource distribution, and implementing targeted policy interventions to ensure equitable and sustainable access to safe drinking water in arid regions.

A Novel Framework for Heterogeneity Decomposition and Mechanism Inference in Spatiotemporal Evolution of Groundwater Storage: Case Study in the North China Plain

AbstractProperly understanding the evolution mechanisms of groundwater storage anomaly (GWSA) is the basis of making effective groundwater management strategies. However, current analysis methods cannot objectively capture the spatiotemporal evolution characteristics of GWSA, which might lead to erroneous inferences of the evolution mechanisms. Here, we developed a new framework to address the challenge of spatiotemporal heterogeneity in the GWSA evolution analysis. It is achieved by integrating the Bayesian Estimator of Abrupt change, Seasonal change, and Trend (BEAST), the Balanced Iterative Reducing and Clustering using Hierarchies (BIRCH), and the Optimal Parameters‐based Geographical Detector (OPGD). In the case study of the North China Plain (NCP), the GWSA time series is divided into four stages by three trend change points in BEAST. An increasing trend of GWSA is observed at Stage IV, and the third trend change point occurs before the third seasonal change point. This distinguishes the positive feedback of anthropogenic interventions and the effects of seasonal precipitations for the first time. Moreover, the spatial distribution of GWSA in the NCP is classified into two clusters by BIRCH in each stage. The differences in GWSA trends and responses to environmental changes between Cluster‐1 and Cluster‐2 are significant. Then the driving effects of 16 factors on the evolution of GWSA are identified using OPGD, in which the contributions of topographic and aquifer characteristics are highlighted by quantitative analysis. This framework provides a novel method for examining the spatiotemporal heterogeneity of GWSA, which can be extended to analyze spatiotemporal trends in GWSA at diverse scales.

Hydrogeochemical and isotopic characterization of the El-Tarf geothermal aquifer (Algerian−Tunisian border): Implications of the regional geodynamic structure and the water−rock interactions

Hydrogeochemical and isotopic characterization of the El-Tarf geothermal aquifer (Algerian−Tunisian border): Implications of the regional geodynamic structure and the water−rock interactions

Identification of Groundwater Table Depth as A Source of Raw Water in Elelim District, Yalimo Regency

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.

Enhancing Groundwater Potential Mapping Through Integrated Validation and Aquifer Characterization in Diverse Geologic Settings: A Case Study of Central Ethiopian Highlands and Adjacent RIFT

Enhancing Groundwater Potential Mapping Through Integrated Validation and Aquifer Characterization in Diverse Geologic Settings: A Case Study of Central Ethiopian Highlands and Adjacent RIFT

Enhancing hydraulic conductivity field characterization through integration of hydraulic head and tracer data using multi-modal neural network models

Characterizing heterogeneous conductivity field is essential for effective groundwater management and controlling contaminant events. The characterization method is currently advancing towards two promising directions: (1) integration of various types of data, such as hydraulic head (H) and tracer concentration (C) data; (2) usage of machine learning methods of AI area. However, no machine learning model has been proposed to integrate H and C data for aquifer characterization effectively. The two data types have different forms: H data being spatial and C data being temporal. This discrepancy creates challenges for effective integration.We developed three machine learning models—HydroCNN, HC-Net1, and HC-Net2. The HydroCNN model could effectively predict hydraulic conductivity (K) fields from H data alone and thus is used as the baseline for evaluating the following models. HC-Net1 and HC-Net2 models are multi-modal neural network models with different architectures. These multi-modal architectures incorporate both convolutional neural network and fully connected neural network modules, designed to integrate H and C data to enhance characterization accuracy. Results indicate that HC-Net2 significantly outperforms the other models, highlighting its capability to leverage the strengths of both data types effectively. Notably, the HC-Net2 model’s improvement is most significant in scenarios where models relying solely on H data perform poorly.

Analytical study on 2D groundwater flow in a sloping unconfined aquifer under spatiotemporal recharge

This study presents a two-dimensional (2D) model for simulating groundwater level variations in sloping aquifers, where rainfall is the primary recharge source. The model uses Heaviside functions to represent spatiotemporal surface recharges and is based on the 2D linearized Boussinesq equation. Analytical solutions were derived using an integral transformation method, allowing for analysis of aquifer characteristics, such as anisotropy, slope, and hydraulic conductivity. In contrast to studies that assume total rainfall becomes recharge, this model employs Horton’s infiltration equation for more accurate estimates, showing strong alignment with field data. The results highlight the significant impact of anisotropy on groundwater flow, particularly when the hydraulic conductivity ratio Kx/Ky exceeds 10, leading to predominantly X-direction flow, with the flow rate increasing by 1.3 times compared to the scenario where Kx/Ky=1 under slope angles θx=θy=5∘. This model also aids in predicting groundwater behavior in small watersheds without field data.

ENVIRONMENTAL ASPECTS OF IN-SITU GROUNDWATER TREATMENT IN WELLS FOR SMALL SETTLEMENTS

The article describes the characteristics of sandy aquifers, the formation of sanitary zones of wells, the creation of an oxidizing zone of wells, measurements of water levels and their annual precipitation were made, the calculation of the colmatation of the aquifer was performed.

The Characterization of Aquifer Parameters in Using Skimming Tubewells Through the Pumping Test Method: A Case Study of Tando Allahyar

Sindh is in the lower reaches of the Indus River; it is most vulnerable to a variety of upstream water development challenges. The aim of this research was to determine aquifer characteristics in the command area of Tando Allahyar-II distributary within the culmination of underground water potential. The hydraulic properties of the aquifer as well as the susceptibility of the formation to tedious extraction and saltwater upcoming were recognized. Three pumping tests were performed at head, middle, and tail reaches along the selected distributary. The drawdowns were measured at head reach (5.1667 h), at middle reach (6.0 h), and at tail reach (19.667 h) of the selected distributary by performing the pumping tests. Groundwater levels were lower at the tail reach compared to those at the head and middle reaches, likely due to a higher concentration of tubewells in the lower reach. The head and middle reaches showed higher groundwater levels, possibly due to constant head conditions promoting infiltration and recharge. The pumping test versus drawdown analysis revealed that the tubewells should be run with 7-h (on) and 4-h (off) operation. Further, the tubewells at all reaches (head, middle, and tail) should be closed for a minimum of 4 h between operations. This strategy would allow safe groundwater extraction, maintain water quality, and prevent water table depletion in the study area. The hydrodynamic and hydro-salinity behaviors were scrutinized in PWMIN 5.3 (version) by means of the MODFLOW mode. The results were estimated to compare the calibration and validation simulation outcomes using measured data. The model was successfully calibrated, and the root mean square (RMS) value of the head tubewell varied between 0.024 and 0.108, whereas it speckled between 0.0166 and 0.0349 for the middle tubewell and between 0.0659 and 0.0069 for the tail tubewell. The RMS values for hydrodynamic behavior for the head, middle, and tail reaches were less than 10%. These values represent a suitable match between the observed and simulated heads when a water table depletion of 1 to 2 m was observed due to extreme pumping. However, the average relative error values, for all validated procedures, were less than 10%.

Characterization of Aquifer using Geo-Electrical Techniques in Kaani, Rivers State, Nigeria

Characterization of Aquifer using Geo-Electrical Techniques in Kaani, Rivers State, Nigeria

Patterns of spatiotemporal variations in the hydrochemistry and controlling factors of bedrock aquifers in the northern region of the Linhuan mining area

Systematically studying the hydrochemical evolution of bedrock groundwater in mining areas during mining process is crucial for effective groundwater resource management and coal mine production. The spatiotemporal characteristics and hydrochemical evolution patterns of the Permian fractured sandstone aquifer (PA) and the Carboniferous Taiyuan Formation limestone aquifer (CTA), both of which are directly associated with coal mining in the northern Linhuan mining area, China, were investigated using multivariate statistical analyses, hydrochemical graphical methods, ion ratio analysis, and a conceptual model. 72 groundwater samples, collected before and after mining, were classified into four groups by hierarchical cluster analysis (HCA). Principal component analysis (PCA) and ion ratio analysis indicated that water-rock interactions involve mineral dissolution (carbonates, gypsum, dolomite, silicates), cation exchange, and common ion effects. Hydrochemical evolution is influenced by bedrock paleotopography, aquifer hydraulic conductivity, and mining drainage. Paletopographic differences significantly influence water-rock interactions and spatial variability in hydrochemistry, with ion concentrations in groundwater increasing as paleotopographic elevation decreases. The pattern of hydraulic conductivity reflects the control exerted by variations in aquifer characteristics on mineral dissolution, leading to minor changes in hydrochemical characteristics. Mining activities disrupt the aquifer's reducing environment, resulting in a significant increase in groundwater SO42− concentration. These findings provide insights and a solid theoretical foundation for studying the hydrochemical variations patterns of groundwater and these control mechanisms in the hidden coal fields of North China.