Human Impact on Groundwater Environment

Topic Information

Dear Colleagues,

This Topic aims to gather novel and innovative works of general interest for the broad audience of the journal related to the environmental implications of ever-growing human activities, with a particular emphasis on the changes these are inducing on groundwater. Global demand for water is projected to outstrip supply by 40% in 2030 and 55% in 2050 as a result of climate change, a rising population, economic growth, rapid urbanization, and increased water–energy–food nexus pressures. Humans are thus now facing the critical challenge of preserving our groundwater resources from biological and chemical contamination induced by its own point and diffuse sources. Addressing this challenge will require a holistic system approach by addressing new issues and emerging contaminants, as well as multiple embedded exposures to ultimately be able to achieve a comprehensive environmental and human health risk assessment.

Consequently, the contributions to this Topic will encompass a broad spectrum of topics in human impact on groundwater resources, including but not limited to: Emerging topics dealing with water resource vulnerability and human impact, including emerging and chemical contaminants; Advances in analytical techniques to monitor and identify sources and processes controlling the budget of human contaminants in water resources; Advances in hydrological processes and hydrodynamic models for investigating water vulnerability to human impact; Analysis of urban growth consequences for water resources and water management; Remote sensing applications for water vulnerability assessment; Linkage between water vulnerability, scarcity, security, and sustainability.

In this Topic, we aim to fill gaps on the application of hydrochemistry (including measurements of radioactive and stable isotope ratios, nutrients, trace elements, and organic components) on environmental research by asking for manuscripts which constitute original contributions on studies developing applications in hydrogeology, nutrient balances, pollution, environmental changes, as well as modeling or empirical studies aimed at improving our mechanistic understanding of short- and long-term chemical variations in global hydrological systems. The submission of inter- and multidisciplinary original research and review papers is particularly encouraged.

Prof. Dr. Zongjun Gao
Dr. Jiutan Liu
Topic Editors

Keywords

Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Energies energies	3.0	6.2	2008	17.5 Days	CHF 2600	Submit
Hydrology hydrology	3.1	4.9	2014	18.6 Days	CHF 1800	Submit
Remote Sensing remotesensing	4.2	8.3	2009	24.7 Days	CHF 2700	Submit
Sustainability sustainability	3.3	6.8	2009	20 Days	CHF 2400	Submit
Water water	3.0	5.8	2009	16.5 Days	CHF 2600	Submit
Earth earth	2.1	3.3	2020	21.7 Days	CHF 1200	Submit

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Published Papers (21 papers)

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All Energies Hydrology Remote Sensing Sustainability Water Earth

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27 pages, 13763 KiB  

Open AccessArticle

Spatial-Temporal Evaluation and Prediction of Water Resources Carrying Capacity in the Xiangjiang River Basin Using County Units and Entropy Weight TOPSIS-BP Neural Network

by Jiacheng Wang, Zhixiang Wang, Zeding Fu, Yingchun Fang, Xuhong Zhao, Xiang Ding, Jing Huang, Zhiming Liu, Xiaohua Fu and Junwu Liu

Sustainability 2024, 16(18), 8184; https://doi.org/10.3390/su16188184 - 19 Sep 2024

Viewed by 898

Abstract

To improve the water resources carrying capacity of the Xiangjiang River Basin and achieve sustainable development, this article evaluates and predicts the Xiangjiang River Basin’s water resources carrying capacity level based on county-level units. This article takes 44 county-level units in the Xiangjiang [...] Read more.

To improve the water resources carrying capacity of the Xiangjiang River Basin and achieve sustainable development, this article evaluates and predicts the Xiangjiang River Basin’s water resources carrying capacity level based on county-level units. This article takes 44 county-level units in the Xiangjiang River Basin as the evaluation target, selects TOPSIS and the entropy weight method to determine weights, calculates the water resources carrying capacity level of the evaluation sample, uses a BP neural network model to calculate the predicted water resources carrying capacity level for the next 5 years, and adds the GIS method for spatiotemporal analysis.(1) The water resources carrying capacity of the Xiangjiang River Basin has remained relatively stable for a long period, with overloaded areas being the majority. (2) There are relatively significant spatial differences in the carrying capacity of water resources: Zixing City, located upstream of the tributary, is far ahead due to its possession of the Dongjiang Reservoir; the water resources carrying capacity in the middle and lower reaches (northern region) is generally higher than that in the upper reaches (southern region). (3) According to the BP neural network model prediction, the water resources carrying capacity of the Xiangjiang River Basin will maintain a stable development trend in 2022, while areas such as Changsha and Zixing City will be in a critical state, and other counties and cities will be in an overloaded state.This study has important references value for the evaluation and early warning work of the Xiangjiang River Basin and related research, providing a scientific and systematic evaluation method and providing strong support for water resource management and planning in Hunan Province and other regions. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1
<p>The Xiangjiang basin.</p> Full article ">Figure 2
<p>Branches of the Xiangjiang River Basin.</p> Full article ">Figure 3
<p>Proportion of water quality above Class III in the Xiangjiang River.</p> Full article ">Figure 4
<p>Figure technological route.</p> Full article ">Figure 5
<p>Guideline layer framework.</p> Full article ">Figure 6
<p>Trend Chart of Water Resources Carrying Capacity in Various County Units of Changsha City.</p> Full article ">Figure 7
<p>Trend Chart of Water Resources Carrying Capacity in Various County Units of Zhuzhou City.</p> Full article ">Figure 8
<p>Trend Chart of Water Resources Carrying Capacity in Various County Units of Xiangtan City.</p> Full article ">Figure 9
<p>Trend Chart of Water Resources Carrying Capacity in Various County Units of Hengyang City.</p> Full article ">Figure 10
<p>Trend Chart of Water Resources Carrying Capacity in Various County Units of Loudi City.</p> Full article ">Figure 11
<p>Trend Chart of Water Resources Carrying Capacity in Various County Units of Chenzhou City.</p> Full article ">Figure 12
<p>Trend Chart of Water Resources Carrying Capacity in Various County Units of Yongzhou City.</p> Full article ">Figure 13
<p>Spatial distribution map of 15-year average water resources carrying capacity of the Xiangjiang River.</p> Full article ">Figure 13 Cont.
<p>Spatial distribution map of 15-year average water resources carrying capacity of the Xiangjiang River.</p> Full article ">Figure 13 Cont.
<p>Spatial distribution map of 15-year average water resources carrying capacity of the Xiangjiang River.</p> Full article ">Figure 13 Cont.
<p>Spatial distribution map of 15-year average water resources carrying capacity of the Xiangjiang River.</p> Full article ">Figure 14
<p>Radar chart of average evaluation value at the criterion level.</p> Full article ">Figure 15
<p>Prediction of the water resources carrying capacity of the Xiangjiang River by BP neural network.</p> Full article ">Figure 16
<p>Forecast spatial distribution of water resources carrying capacity in the next 5 years.</p> Full article ">

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Supplementary material:
Supplementary File 1 (ZIP, 92 KiB)

15 pages, 5274 KiB  

Open AccessArticle

Optimization of Advance Drainage Borehole Layout Based on Visual Modflow

by Yue Li, Yunpeng Zhang, Yajie Ma and Fangang Meng

Water 2024, 16(18), 2613; https://doi.org/10.3390/w16182613 - 14 Sep 2024

Viewed by 400

Abstract

It is an effective measure to prevent water damage in coal mines in order to construct drainage boreholes in water-filled aquifers of a working face roof. The hydrogeological parameters of the roof water-filled aquifer and the parameters of the drainage borehole are closely [...] Read more.

It is an effective measure to prevent water damage in coal mines in order to construct drainage boreholes in water-filled aquifers of a working face roof. The hydrogeological parameters of the roof water-filled aquifer and the parameters of the drainage borehole are closely related to the underground drainage effect. Taking the 3085 working face of the Donghuantuo Mine in Kailuan as an example, the influence degree of hydrogeological parameters and hydrophobic borehole parameters on the amount of drainage water was analyzed using the generalized gray correlation degree. Based on Visual Modflow, the 3D groundwater visualization model was established and the dredging borehole was generalized into the pumping borehole. By changing the main influencing factors, the design optimization of the advanced hydrophobic borehole was discussed. The results showed that the aquifer thickness had a great influence on the amount of water discharged, and the influence degree of the sharp angle between the formation and the direction of drilling, the depth of the final hole, the azimuth angle of drilling, the dip angle of drilling, the elevation of the final hole and the elevation of the borehole on the amount of water discharged decreased successively. Based on the simulation calculation, it could be observed that the hydrophobic borehole should be placed in a position with a larger accumulated thickness of the aquifer to have a better effect of hydrophobic depressurization. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1
<p>3085 working face drainage borehole location diagram.</p> Full article ">Figure 2
<p>3085 typical dynamic curve of drainage drilling in the working face.</p> Full article ">Figure 3
<p>Schematic diagram of geometric model with a 1:1 horizontal longitudinal ratio.</p> Full article ">Figure 4
<p>Three-dimensional model aquifer and well display diagram. (<b>a</b>) Strong aquifer layers. (<b>b</b>) Aquifer layers. (<b>c</b>) Weak permeable layers. (<b>d</b>) Aquiclude layers.</p> Full article ">Figure 5
<p>Elevation fitting result diagram of the coal seam 8 floor.</p> Full article ">Figure 6
<p>Dongguan 55 hole water level change fitting curve diagram.</p> Full article ">Figure 7
<p>Contour map of the total thickness of the roof aquifer.</p> Full article ">Figure 8
<p>Distribution position and isoline diagram of aquifer drain hole. (<b>a</b>) Before optimization. (<b>b</b>) After optimization.</p> Full article ">

15 pages, 8589 KiB  

Open AccessArticle

Characterization of Groundwater Hydrochemistry and Temporal Dynamics of Water Quality in the Northern Baiquan Spring Basin

by Di Wu, Bo Li, Yuxing Li, Qingbin Li, Chen Sheng, Jiutan Liu, Min Wang, Yangyang Min, Jianguo Feng, Yuqi Zhang and Jieqing Yu

Water 2024, 16(17), 2519; https://doi.org/10.3390/w16172519 - 5 Sep 2024

Viewed by 443

Abstract

Groundwater represents a critical resource for sustaining the livelihoods of both urban and rural populations, facilitating economic and social development, and preserving ecological equilibrium. This study leverages groundwater quality monitoring data from the northern Baiquan spring basin (NBSB) to elucidate groundwater hydrochemical characteristics [...] Read more.

Groundwater represents a critical resource for sustaining the livelihoods of both urban and rural populations, facilitating economic and social development, and preserving ecological equilibrium. This study leverages groundwater quality monitoring data from the northern Baiquan spring basin (NBSB) to elucidate groundwater hydrochemical characteristics and decipher the temporal variability in water quality. Findings suggest that groundwater within the NBSB is predominantly weakly alkaline and characterized as hard-fresh, with HCO₃⁻ and Ca²⁺ as the predominant ions, which collectively demarcate the hydrochemical type as predominantly HCO₃-Ca. The principal constituents of NBSB groundwater are influenced predominantly by the weathering of carbonates and silicates alongside the dissolution of gypsum and halite. Moreover, agricultural operations and similar human activities have exerted an impact on the hydrochemical attributes of NBSB’s groundwater. Generally, fluctuations in groundwater anion concentrations over time are more pronounced than those of cations, exemplified by a significant upward trend in the major ion concentrations at the BQ03 monitoring site in the later stages. While the general groundwater quality within the NBSB is deemed satisfactory, most monitoring sites have experienced an escalation in water quality indices over time, notably at BQ03, which warrants serious attention. The findings of this research contribute to the efficient management and sustainable utilization of groundwater resources in the NBSB. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1
<p>Location map of BSB and groundwater monitoring points.</p> Full article ">Figure 2
<p>Plots of (<b>a</b>) bar chart of chemical composition and (<b>b</b>) TH vs. TDS water type.</p> Full article ">Figure 3
<p>Durov plot of groundwater hydrochemistry.</p> Full article ">Figure 4
<p>Major ion ratios diagram in groundwater of NBSB. (<b>a</b>) Ratio of Na⁺ to Cl⁻; (<b>b</b>) The ratio of Ca²⁺ + Mg²⁺ to SO₄²⁻ + HCO₃⁻; (<b>c</b>) The ratio of Ca²⁺ to SO₄²⁻; (<b>d</b>) The ratio of NO₃⁻/Na⁺ to Cl⁻/Na⁺.</p> Full article ">Figure 5
<p>Relationship between the SI and TDS for groundwater samples.</p> Full article ">Figure 6
<p>Temporal variation of the major cation content in groundwater. (<b>a</b>) Time variation of Ca²⁺ content; (<b>b</b>) Time variation of Mg²⁺ content; (<b>c</b>) Time variation of Na²⁺ content; (<b>d</b>) Time variation of K⁺ content.</p> Full article ">Figure 7
<p>Temporal variation of the major anion content in groundwater. (<b>a</b>) Time variation of HCO₃⁻ content; (<b>b</b>) Time variation of SO₄²⁻ content; (<b>c</b>) Time variation of Cl⁻ content; (<b>d</b>) Time variation of NO₃⁻ content.</p> Full article ">Figure 8
<p>Temporal variation of the EWQI values in groundwater. (<b>a</b>) Time variation of EWQI value in BQ01; (<b>b</b>) Time variation of EWQI value in BQ03; (<b>c</b>) Time variation of EWQI value in BQ04; (<b>d</b>) Time variation of EWQI value in BQ06; (<b>e</b>) Time variation of EWQI value in BQ07.</p> Full article ">

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Supplementary material:
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18 pages, 3957 KiB  

Open AccessArticle

Predicting Arsenic Contamination in Groundwater: A Comparative Analysis of Machine Learning Models in Coastal Floodplains and Inland Basins

by Zhenjie Zhao, Amit Kumar and Hongyan Wang

Water 2024, 16(16), 2291; https://doi.org/10.3390/w16162291 - 14 Aug 2024

Viewed by 780

Abstract

Arsenic (As) contamination in groundwater represents a major global health threat, potentially impacting billions of individuals. Elevated As concentrations are found in river floodplains across south and southeast Asia, as well as in the inland basins of China, despite varying sedimentological and hydrogeochemical [...] Read more.

Arsenic (As) contamination in groundwater represents a major global health threat, potentially impacting billions of individuals. Elevated As concentrations are found in river floodplains across south and southeast Asia, as well as in the inland basins of China, despite varying sedimentological and hydrogeochemical conditions. The specific mechanisms responsible for these high As levels remain poorly understood, complicating efforts to predict and manage the contamination. Applying hydro-chemical, geological, and soil parameters as explanatory variables, this study employs multiple linear regression (MLIR) and random forest regression (RFR) models to estimate groundwater As concentrations in these regions. Additionally, random forest classification (RFC) and multivariate logistic regression (MLOR) models are applied to predict the probability of As levels exceeding 10 μg/L in the Hetao Basin (China) and Bangladesh. Model validation reveals that RFR explains 80% and 70% of spatial variability of As concentration in the Hetao Basin and Bangladesh, respectively, outperforming MLIR, which accounts for only 35% and 32%. Similarly, RFC outperforms MLOR in predicting high As probability, achieving correct classification rates of 98.70% (Hetao Basin) and 98.25% (Bangladesh) on training datasets, and 82.76% (Hetao Basin) and 91.20% (Bangladesh) on validation datasets. The performance of the MLOR model on the validation set yields accuracy rates of 81.60% and 72.18%, respectively. In the Hetao Basin, Ca²⁺, redox potential (Eh), Fe, pH, SO₄²⁻, and Cl⁻ are key predictors of As contamination, while in Bangladesh, soil organic carbon (SOC), pH, and SO₄²⁻ are significant predictors. This study underscores the potential of random forest (RF) models as robust tools for predicting groundwater As contamination. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1
<p>Spatial distribution of groundwater As concentrations in the Hetao Basin (data from [<a href="#B16-water-16-02291" class="html-bibr">16</a>,<a href="#B44-water-16-02291" class="html-bibr">44</a>]).</p> Full article ">Figure 2
<p>Spatial distribution of groundwater arsenic concentrations in Bangladesh (data from [<a href="#B48-water-16-02291" class="html-bibr">48</a>]).</p> Full article ">Figure 3
<p>Flow diagram of methodologies adopted for this study.</p> Full article ">Figure 4
<p>Graphical presentation of Pearson’s Correlation Coefficient. (<b>a</b>): Hetao Basin; (<b>b</b>): Bangladesh. Abbreviations: OCD: organic carbon density; CC: clay content; SOC: soil organic carbon; BD: bulk density; SC: silt content; CEC: cation exchange capacity; DOC: dissolved organic carbon; AsTot: total arsenic.</p> Full article ">Figure 5
<p>Relationship between predicted and measured As contamination for MLIR model. (<b>a</b>): Training data for Hetao Basin; (<b>b</b>): Training data for Bangladesh; (<b>c</b>): Validation data for Hetao Basin; (<b>d</b>): Validation data for Bangladesh.</p> Full article ">Figure 6
<p>Relationship between predicted and measured As contamination for RFR model. (<b>a</b>): Training data for Hetao Basin; (<b>b</b>): Training data for Bangladesh; (<b>c</b>): Validation data for Hetao Basin; (<b>d</b>): Validation data for Bangladesh.</p> Full article ">Figure 7
<p>(<b>a</b>) AUC-ROC of adopted models in Hetao Basin. (<b>b</b>) AUC-ROC of adopted models in Bangladesh.</p> Full article ">

20 pages, 13040 KiB  

Open AccessArticle

Influence of Structural Symmetry of Fault Zones on Fluid-Induced Fault Slips and Earthquakes

by Zhiyong Niu and Bing Bai

Water 2024, 16(8), 1118; https://doi.org/10.3390/w16081118 - 15 Apr 2024

Viewed by 926

Abstract

Subsurface fluid injection and extraction can reactivate faults and induce earthquakes. In current research, faults are typically described as symmetrical structures and the presence of asymmetric structures is often overlooked. The reality is that numerous asymmetric faults exist within the Earth’s crust. The [...] Read more.

Subsurface fluid injection and extraction can reactivate faults and induce earthquakes. In current research, faults are typically described as symmetrical structures and the presence of asymmetric structures is often overlooked. The reality is that numerous asymmetric faults exist within the Earth’s crust. The architectural and permeability characteristics of fault zones differ significantly between symmetrical and asymmetrical faults. These differences may have a great influence on fault stability during fluid injection or extraction. In this study, the impact of fault zone structures on fluid-induced slips and seismic activity were investigated through numerical analysis. The findings indicated that symmetrical faults were more likely to induce larger slips and earthquakes during various subsurface fluid operations. For asymmetric faults, larger induced slips occurred when fluid was operated in a hanging wall reservoir than in a footwall reservoir. In symmetrical faults, the opposite was true. When evaluating the stability of a fault in subsurface fluid engineering, the fault structure and fluid pattern and their combined effects must be considered comprehensively. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1
<p>Schematic diagram of fluid-induced earthquakes.</p> Full article ">Figure 2
<p>Structure of the symmetrical fault (<b>a</b>) and the asymmetric fault (<b>b</b>).</p> Full article ">Figure 3
<p>Contacting bodies and the trajectory of node S1 in finite-sliding contact.</p> Full article ">Figure 4
<p>Slide line segment.</p> Full article ">Figure 5
<p>Basic model.</p> Full article ">Figure 6
<p>Reservoir categories.</p> Full article ">Figure 7
<p>Diagram of the six different injection and extraction patterns.</p> Full article ">Figure 8
<p>The induced fault slip displacement of the upper reservoir−Fluid Pattern I.</p> Full article ">Figure 9
<p>The pore−pressure distribution of the symmetrical fault (<b>a</b>) and the asymmetric fault (<b>b</b>) under Fluid Pattern I.</p> Full article ">Figure 10
<p>The shear stress distribution of the symmetrical fault (<b>a</b>) and the asymmetric fault (<b>b</b>) under Fluid Pattern I.</p> Full article ">Figure 11
<p>The shear stress along the fault plane of the symmetrical fault (<b>a</b>) and the asymmetric fault (<b>b</b>) under Fluid Pattern I.</p> Full article ">Figure 12
<p>The induced fault slip displacement of the upper reservoir−Fluid Pattern II.</p> Full article ">Figure 13
<p>The pore-pressure distribution of the symmetrical fault (<b>a</b>) and the asymmetric fault (<b>b</b>) under Fluid Pattern II.</p> Full article ">Figure 14
<p>The induced fault slip displacement of the upper reservoir−Fluid Pattern III.</p> Full article ">Figure 15
<p>The vertical displacement distribution of the symmetrical fault (<b>a</b>) and the asymmetric fault (<b>b</b>) under the upper reservoir−Fluid Pattern III.</p> Full article ">Figure 16
<p>The induced fault slip displacement of the upper reservoir−Fluid Pattern IV.</p> Full article ">Figure 17
<p>The induced fault slip displacement of the upper reservoir−Fluid Pattern V.</p> Full article ">Figure 18
<p>The induced fault slip displacement of the upper reservoir−Fluid Pattern VI.</p> Full article ">Figure 19
<p>The induced fault slip displacements of the lower reservoir under the six fluid patterns: Pattern I (<b>a</b>), Pattern II (<b>b</b>), Pattern III (<b>c</b>), Pattern IV (<b>d</b>), Pattern V (<b>e</b>), and Pattern VI (<b>f</b>).</p> Full article ">

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Supplementary material:
Supplementary File 1 (ZIP, 474 KiB)

14 pages, 3404 KiB  

Open AccessArticle

The Challenge Posed by Emerging Environmental Contaminants: An Assessment of the Effectiveness of Phenoxyethanol Biological Removal from Groundwater through Mesocosm Experiments

by Laura Ducci, Pietro Rizzo, Antonio Bucci, Riccardo Pinardi, Pamela Monaco and Fulvio Celico

Sustainability 2024, 16(5), 2183; https://doi.org/10.3390/su16052183 - 6 Mar 2024

Cited by 2 | Viewed by 1290

Abstract

The occurrence of emerging pollutants (EPs) such as pharmaceuticals and personal care products (PPCPs) has raised serious concerns about the possible adverse effects on ecosystem integrity and human health. Wastewater treatment facilities appear to be the main sources of PPCPs released in aquatic [...] Read more.

The occurrence of emerging pollutants (EPs) such as pharmaceuticals and personal care products (PPCPs) has raised serious concerns about the possible adverse effects on ecosystem integrity and human health. Wastewater treatment facilities appear to be the main sources of PPCPs released in aquatic environments. This research examines the effectiveness of groundwater microbial community activities to remove phenoxyethanol (Phy-Et), currently exploited as a preservative in many cosmetic formulations at a maximum concentration of 1% but which has shown, at higher levels of exposure, adverse systemic effects on animals. Mesocosm experiments were carried out for 28 days using two different concentrations of the substance (5.2 mg/L and 27.4 mg/L). The main results obtained through chemical and microbiological investigations revealed a significant Phy-Et reduction (≈100% when added at a concentration of 5.2 mg/L and ≈84% when added at a concentration of 27.4 mg/L), demonstrating that some autochthonous microorganisms in the analyzed samples played a “key role” in removing this compound, despite its proven antimicrobial activity. Nevertheless, the decrease in the “natural attenuation” efficacy (≈16%) when using higher concentrations of the chemical suggests the existence of a “dose-dependent effect” of Phy-Et on the process of biodegradation. Biomolecular investigations carried out through next-generation sequencing (NGS) revealed (i) the presence of a significant fraction of hidden microbial diversity to unravel, (ii) variations of the composition and species abundance of the groundwater microbial communities induced by Phy-Et, and (iii) a biodiversity reduction trend correlated to the increase of Phy-Et concentrations. Overall, the preliminary information obtained from the experiments carried out at the laboratory scale appears encouraging, although it reflects only partially the complexity of the phenomena that occur in natural environments and influences their “auto-purification capability”. Accordingly, this research paves the way for more in-depth investigations to develop appropriate tools and protocols to evaluate the occurrence and fate of Phy-Et in nature and assess the impact of its release and the effects of long-term exposure (even at low concentrations) on ecosystems and health. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1
<p>(<b>a</b>) Geological map and section at basin scale (from Ducci et al., 2022, modified [<a href="#B21-sustainability-16-02183" class="html-bibr">21</a>]); (1) AES8: Emiliano–Romagnolo superiore synthem—Ravenna subsynthem; (2) AES8a: Emiliano–Romagnolo superiore synthem—Modena subsynthem; (3) main thrust; (4) borehole; (5) toponym; (6) quoted point; (7) geological section’s trace; (8) stream; (9) meteorological station; (10) wastewaters treatment plant “Parma Ovest”; (11) study area; (from Ducci et al., 2022, modified [<a href="#B21-sustainability-16-02183" class="html-bibr">21</a>]). (<b>b</b>) Geological section at basin scale (the trace is shown in (<b>a</b>)): (1) fill material, (2) grey/light blue clay and silt; (3) yellow/brown clay and silt; (4) red clay and silt; (5) silt; (6) sand; (7) gravel and sand; (8) gravel and clay/silt; (9) gravel; (10) Code of Geological Unit (sensu Di Dio et al., 2005 [<a href="#B27-sustainability-16-02183" class="html-bibr">27</a>]): AES1: Emiliano–Romagnolo superiore synthem—Monterlinzana subsynthem; AES2: Emiliano–Romagnolo superiore synthem—Maiatico subsynthem; AES7a: Emiliano–Romagnolo superiore synthem—Villa Verucchio subsynthem—Niviano unit; AES7b: Emiliano–Romagnolo superiore synthem—Villa Verucchio subsynthem—Vignola unit; AES8: Emiliano–Romagnolo synthem—Ravenna subsynthem.</p> Full article ">Figure 2
<p>Geological section at site scale (from Ducci et al., 2022, modified [<a href="#B21-sustainability-16-02183" class="html-bibr">21</a>]).</p> Full article ">Figure 3
<p>(<b>a</b>) Groundwater flow net in May 2022; (<b>b</b>) groundwater flow net in October 2022 (from Ducci et al., 2022, modified [<a href="#B21-sustainability-16-02183" class="html-bibr">21</a>]).</p> Full article ">Figure 4
<p>(<b>a</b>) Groundwater microbial community characterization and assessment of Phy-Et background contamination; (<b>b</b>) experimental protocol setup of mesocosms.</p> Full article ">Figure 5
<p>Microbial community composition at phylum (<b>on the left</b>) and genus (<b>on the right</b>) levels of groundwater collected from the piezometer Pz3. Taxa with relative abundance values below 1% and 2% for phylum and genus levels, respectively, are labeled “Other”. U. m. refers to unclassified microorganisms.</p> Full article ">Figure 6
<p>Mesocosm microbial community composition at phylum (<b>on the left</b>) and genus (<b>on the right</b>) levels of Lines α and β. Taxa with relative abundance values below 1% and 2% for phylum and genus levels, respectively, are labeled “Other”. U. m. refers to unclassified microorganisms. The relative abundance of each taxon has been calculated as the mean of values of the triplicate experiments.</p> Full article ">

17 pages, 3030 KiB  

Open AccessArticle

Source Apportionment and Health Risk Assessment of Groundwater Potentially Toxic Elements (PTEs) Pollution Characteristics in an Accident Site in Zhangqiu, China

by Min Wang, Xiaoyu Song, Yu Han, Guantao Ding, Ruilin Zhang, Shanming Wei, Shuai Gao and Yuxiang Liu

Water 2024, 16(5), 768; https://doi.org/10.3390/w16050768 - 4 Mar 2024

Viewed by 1073

Abstract

In order to understand the pollution degree and source of potentially toxic elements (PTEs) in groundwater around the accident site and evaluate their harm to human health, 22 groundwater samples were collected around the accident well, and the contents of As, Cd, Cr, [...] Read more.

In order to understand the pollution degree and source of potentially toxic elements (PTEs) in groundwater around the accident site and evaluate their harm to human health, 22 groundwater samples were collected around the accident well, and the contents of As, Cd, Cr, Cu, Hg, Ni, Pb, Zn, CH₂Cl₂ and C₂H₄Cl₂ were determined. On the basis of water quality evaluation, the source apportionment method combining qualitative and quantitative analysis was used to determine the main sources of PTEs in the region, and the health risk assessment model was used to evaluate the health risk of PTEs to the human body. The results show that pH, TDS, Th and COD all exceed the standard to varying degrees, among which TH is the index with the largest number exceeding the standard. The quality of the groundwater environment in the study area is at a very poor level, and the F value is between 7.25 and 8.49. The exposure results model showed that there was no non-carcinogenic risk of PTEs in the study area, and the health risk of oral intake in the exposed population was greater than that of skin contact. Compared with adults, children were more vulnerable to the health risk stress of PTEs in groundwater. The total carcinogenic risk is higher than the total non-carcinogenic risk. As, Cd and Cr are the primary factors causing carcinogenic health risks in this area. Principal component analysis (PCA) was used to analyze the sources of PTEs in groundwater, and three principal components were extracted. It was preliminarily determined that PTE pollution was mainly related to agricultural sources, anthropogenic industrial sources and industrial sedimentation sources. The results of positive definite factor matrix analysis (PMF) were basically similar to those of PCA, but PMF further clarified the contribution rate of three pollution sources, among which agricultural sources contributed the most to the accumulation of PTEs. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1
<p>The schematic diagram of sampling points in the study area.</p> Full article ">Figure 2
<p>Distribution map of PTE content in groundwater.</p> Full article ">Figure 3
<p>Correlation analysis matrix.</p> Full article ">Figure 4
<p>Analytical results of PMF model.</p> Full article ">Figure 5
<p>The proportion of PTE factors in groundwater.</p> Full article ">Figure 6
<p>Contribution rate distribution diagram of sources.</p> Full article ">

16 pages, 1104 KiB  

Open AccessReview

Influencing Factors and Evaluation of Groundwater Ecological Function in Arid/Semiarid Regions of China: A Review

by Haohao Cui, Mingjiang Yan, Qian Wang, Guanghui Zhang, Huimin Feng and Xujuan Lang

Sustainability 2024, 16(4), 1631; https://doi.org/10.3390/su16041631 - 16 Feb 2024

Cited by 1 | Viewed by 977

Abstract

In arid and semi-arid areas, due to drought climate and shortage of water resources, groundwater is crucial for natural ecological protection and economic development. It serves a dual role as a resource function and an ecological function. However, with the continuous improvement of [...] Read more.

In arid and semi-arid areas, due to drought climate and shortage of water resources, groundwater is crucial for natural ecological protection and economic development. It serves a dual role as a resource function and an ecological function. However, with the continuous improvement of the exploitation and utilization of groundwater by human activities during rapid economic development, the phenomenon of groundwater overexploitation is becoming more and more serious, which has destroyed the natural balance of groundwater recharge and discharge. As a result, natural vegetation has lost the maintenance of the ecological function of groundwater, and a series of ecological and environmental problems have occurred, such as natural vegetation degradation, land desertification, sandstorms, and so on. In recent years, scholars have carried out research on groundwater resource management and optimization of water resource allocation, trying to solve the problem of water balance in arid regions. However, there is still a lack of comprehensive understanding and systematization regarding influencing factors and degeneration mechanisms related to groundwater’s ecological function. By summarizing and analyzing the previous research results, this paper summarizes the influencing factors, evaluation methods, existing problems and future directions of groundwater ecological function research in China to provide a reference for rational exploitation and utilization of groundwater and ecological protection. This paper is divided into four main contents. The first part introduces the definition of groundwater ecological function (GEF); the second part summarizes the research status of influencing factors of GEF, including the groundwater table depth, vegetation root system and lithologic structure of vadose zone, etc.; the third part analyzes the evaluation of groundwater ecological function; the fourth part discusses the existing problems in the study of groundwater ecological functions, and based on the above research the evaluation framework of GEF is proposed with the Shiyang River basin as a case study; and finally, it highlights the future research directions about GEF. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1
<p>Coverage of natural vegetation under different ecological water levels in arid regions.</p> Full article ">Figure 2
<p>Water use sources and strategy of vegetation.</p> Full article ">Figure 3
<p>Capillary water rise height and retained water after the gravity release of different lithologic structures in the vadose zone. Note: H₁ is the height of support capillary water rise in a single lithology vadose zone, and H₂ is the height of support capillary water rise in a multi-layered lithology vadose zone. Due to the influence of the fine-grained layer in the multilayer structure, H₂ &gt; H₁. The arrow indicates a groundwater table drop event. Both vadose zone structures will retain water in the former capillary zone after the groundwater table drops, but the vadose zone with a multilayer structure retains more water.</p> Full article ">Figure 4
<p>Groundwater function evaluation and zoning system in arid region.</p> Full article ">Figure 5
<p>Change characteristics of groundwater ecological function in natural oasis area in the lower reaches of the Shiyang River basin.</p> Full article ">

17 pages, 17349 KiB  

Open AccessArticle

Hydrochemical Characteristics, Controlling Factors and Strontium Enrichment Sources of Groundwater in the Northwest Plain of Shandong Province, China

by Jingpeng Chen, Xiaohua Wu, Jichu Zhao, Shuai Liu, Yuqi Zhang, Jiutan Liu and Zongjun Gao

Water 2024, 16(4), 550; https://doi.org/10.3390/w16040550 - 10 Feb 2024

Viewed by 1028

Abstract

To elucidate the hydrochemical characteristics, controlling factors, sources and mechanisms of strontium ion enrichment in groundwater in the northwest plain of Shandong Province, China, 88 groundwater samples were collected, including 51 shallow pore groundwater samples, 29 deep pore groundwater samples and 8 karst [...] Read more.

To elucidate the hydrochemical characteristics, controlling factors, sources and mechanisms of strontium ion enrichment in groundwater in the northwest plain of Shandong Province, China, 88 groundwater samples were collected, including 51 shallow pore groundwater samples, 29 deep pore groundwater samples and 8 karst groundwater samples. The hydrochemical characteristics of the different types of groundwater were quite different. The karst groundwater samples were all fresh water with a single hydrochemical type, either HCO₃-Ca or HCO₃-Ca·Mg. The deep pore groundwater samples were mainly brackish water, and the shallow pore groundwater samples were brackish water–salt water, which has complex hydrochemical types. The hydrochemical characteristics of all the types of groundwater were controlled by mineral dissolution and active positive cation exchange. In shallow pore groundwater, deep pore groundwater and karst groundwater, the dissolution of silicate, evaporite and carbonate minerals dominated the hydrogeochemical process. The strontium in groundwater was derived from the dissolution of minerals with strontium isomorphism. The average contents of strontium in shallow, deep and karst groundwater were 1.59 mg/L, 0.58 mg/L and 0.50 mg/L, respectively. The strontium in shallow pore groundwater was mainly derived from the enrichment of groundwater runoff, and its sources are abundant, with silicic rock being the main source. The deep pore groundwater mainly derived from the evaporative minerals containing strontium, and the karst water mainly derived from carbonate rock dissolution with similar characteristics. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1
<p>Location of the sampling points in the northwest plain of Shandong Province.</p> Full article ">Figure 2
<p>Box diagram of hydrochemical components of different groundwater types (<b>a</b>,<b>b</b>) in the northwest plain of Shandong Province.</p> Full article ">Figure 3
<p>Hydrochemical Piper diagram of groundwater source water in the northwest plain of Shandong Province.</p> Full article ">Figure 4
<p>Gibbs diagram of hydrochemistry in groundwater source water (<b>a</b>,<b>b</b>) in northwest plain of Shandong Province.</p> Full article ">Figure 5
<p>Relative contribution of rock weathering (<b>a</b>) and dissolution (<b>b</b>) to groundwater composition in northwest plain of Shandong Province.</p> Full article ">Figure 6
<p>Alternate cation adsorption (<b>a</b>), and chlor-alkali index (<b>b</b>) of groundwater source in northwest plain of Shandong Province.</p> Full article ">Figure 7
<p>Relationship between hydrochemistry and human activities in the northwest plain of Shandong Province.</p> Full article ">Figure 8
<p>The relationship between Na⁺ and Cl⁻ (<b>a</b>), Na+ and HCO₃⁻ (<b>b</b>) in groundwater source water in the northwest plain of Shandong Province.</p> Full article ">Figure 9
<p>Relationships between (Ca²⁺ + Mg²⁺) and (HCO₃⁻ + SO₄²⁻) (<b>a</b>), (Ca²⁺ + Mg²⁺-HCO₃⁻) and (SO₄²⁻-Na⁺-Cl⁻) (<b>b</b>) in the northwest plain of Shandong Province.</p> Full article ">Figure 10
<p>Hydrochemical field evolution model of the northwest plain of Shandong Province.</p> Full article ">Figure 11
<p>Strontium enrichment model of karst groundwater in the northwest plain of Shandong Province.</p> Full article ">

19 pages, 8060 KiB  

Open AccessArticle

Evaluation of Groundwater Vulnerability of Yishu River Basin Based on DRASTIC-GIS Model

by Jiaqi Hu, Peng Yang, Qiang Li, Min Wang, Jianguo Feng, Zongjun Gao and Jiutan Liu

Water 2024, 16(3), 429; https://doi.org/10.3390/w16030429 - 29 Jan 2024

Cited by 1 | Viewed by 1236

Abstract

The evaluation of vulnerability is a crucial aspect in the sustainable development, utilization, and preservation of groundwater resources. This study utilizes a comprehensive approach, integrating systematic analysis of hydrogeological conditions and the utilization of observed and collected data. The evaluation of groundwater vulnerability [...] Read more.

The evaluation of vulnerability is a crucial aspect in the sustainable development, utilization, and preservation of groundwater resources. This study utilizes a comprehensive approach, integrating systematic analysis of hydrogeological conditions and the utilization of observed and collected data. The evaluation of groundwater vulnerability in the Yishu River Basin (YRB) was conducted by employing the DRASTIC model, along with the zone overlay function of GIS software. Seven evaluation indicators were considered in this assessment. The findings demonstrate that the groundwater vulnerability in the YRB can be categorized into five divisions: excellent, good, medium, poor, and very poor, accounting for 14.5%, 42.3%, 27.9%, 14.0%, and 1.3% respectively. The areas with low vulnerability are predominantly located in the eastern part of the study area, covering the largest proportion of the total area. Conversely, areas with high vulnerability are found alongside both banks of the Shu River, forming narrow strips. Although these areas have smaller overall coverage, they contain dispersed water sources that require careful attention. These research findings provide valuable scientific insights and serve as a reference for urban planning, land use management, and groundwater resource protection in the YRB. The formulation and adoption of targeted protection measures in accordance with different groundwater vulnerability zoning, the formulation of scientific groundwater resource development and utilization programs, and execution of land resource planning are of great significance from the perspective of groundwater resource protection. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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<p>Hydrogeological map and distribution map of monitoring points in the YRB.</p> Full article ">Figure 2
<p>Outline map of landform zoning in the study area.</p> Full article ">Figure 3
<p>Flowchart of the DRASTIC methodology.</p> Full article ">Figure 4
<p>Scoring map for groundwater depth (D).</p> Full article ">Figure 5
<p>Scoring map for net recharge (R).</p> Full article ">Figure 6
<p>Scoring map for aquifer media (A).</p> Full article ">Figure 7
<p>Scoring map for soil media (S).</p> Full article ">Figure 8
<p>Scoring map for topography (T).</p> Full article ">Figure 9
<p>Scoring map for medium in seepage area (I).</p> Full article ">Figure 10
<p>Scoring map for hydraulic conductivity (C).</p> Full article ">Figure 11
<p>Evaluation of vulnerability of YRB.</p> Full article ">

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Supplementary material:
Supplementary File 1 (ZIP, 1536 KiB)

13 pages, 2769 KiB  

Open AccessArticle

Estimating Thermal Impact on Groundwater Systems from Heat Pump Technologies: A Simplified Method for High Flow Rates

by David Krcmar, Tibor Kovacs, Matej Molnar, Kamila Hodasova and Martin Zatlakovic

Hydrology 2023, 10(12), 225; https://doi.org/10.3390/hydrology10120225 - 29 Nov 2023

Viewed by 1841

Abstract

This research delves into the potential thermal effects on underground water systems caused by the use of thermal technologies involving extraction and injection wells. We developed a unique approach that combines straightforward calculations with computer-based modeling to evaluate thermal impacts when water flow [...] Read more.

This research delves into the potential thermal effects on underground water systems caused by the use of thermal technologies involving extraction and injection wells. We developed a unique approach that combines straightforward calculations with computer-based modeling to evaluate thermal impacts when water flow rates exceed 2 L/s. Our model, based on a system with two wells and a steady water flow, was used to pinpoint the area around the thermal technology where the temperature varied by more than 1 °C. Our findings suggest that the data-based relationships we derived from our model calculations provide a cautious estimate of the size of the affected area, or ‘thermal cloud’. However, it is important to note that our model’s assumptions might not fully account for the complex variables present in real-world underground water systems. This highlights a need for more research and testing. A key contribution of our study is the development of a new method to assess the thermal impact of operations involving heat pumps. In conclusion, while our proposed method needs more fine-tuning, it shows promise in estimating temperature changes within water-bearing rock layers, or aquifers. This is crucial in the effective use of thermal technologies while also ensuring the protection and sustainable management of our underground water resources. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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<p>Schematic diagram of the situation of the heat pump well.</p> Full article ">Figure 2
<p>Context of groundwater level and flow lines around the heat pump with backward water flow between wells.</p> Full article ">Figure 3
<p>Range of the thermal cloud with marked width (Y_cloud) and length (X_cloud).</p> Full article ">Figure 4
<p>Graph of the dependence of the additional distance on environmental parameters.</p> Full article ">Figure 5
<p>Graph of the dependence of the thermal cloud width on the return flow width between the wells.</p> Full article ">

12 pages, 967 KiB  

Open AccessArticle

Heavy Metal Content Characteristics and Pollution Source Analysis of Shallow Groundwater in Tengzhou Coal Mining Area

by Beibei Yan, Qianqian Wei, Xinfeng Li, Xiaoyu Song, Zongjun Gao, Jiutan Liu, Ruilin Zhang and Min Wang

Water 2023, 15(23), 4091; https://doi.org/10.3390/w15234091 - 25 Nov 2023

Cited by 1 | Viewed by 1425

Abstract

This study analyzed the sources of total metal elements using the positive matrix factorization (PMF) model and conducted human health risk assessment for adults and children using the health risk assessment model recommended by the United States Environmental Protection Agency (USEPA). According to [...] Read more.

This study analyzed the sources of total metal elements using the positive matrix factorization (PMF) model and conducted human health risk assessment for adults and children using the health risk assessment model recommended by the United States Environmental Protection Agency (USEPA). According to the health risk assessment, As is the main contributor to the non-carcinogenic risk of groundwater in Tengzhou, with drinking water as the main exposure route. Regarding carcinogenic risks (CR), the values of As and Cr for adults and children were higher than 1 × 10⁻⁴, with drinking water as the main exposure route. Therefore, As is the largest contributor to the CR of groundwater for adults and children and drinking water is the main exposure route in the study area. The primary exposure pathways are oral intake and dermal contact, with oral intake presenting a significant risk. The carcinogenic risks according to principal component analysis (PCA) and PMF analysis showed that the main sources of heavy metals in shallow groundwater in Tengzhou City are agricultural, industrial, natural, and industrial deposition sources, with contribution rates of 21.7%, 27.2%, 31.0%, and 20.1%, respectively. In particular, natural sources are the largest contributor to the accumulation of heavy metals. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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<p>Groundwater sampling sites in Tengzhou.</p> Full article ">Figure 2
<p>Correlation coefficients between metal elements in groundwater.</p> Full article ">Figure 3
<p>Contribution rates of heavy metal pollution sources in PMF.</p> Full article ">

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Supplementary material:
Supplementary File 1 (ZIP, 12 KiB)

17 pages, 3725 KiB  

Open AccessArticle

A Comprehensive Study on the Hydrogeochemical and Isotope Characteristics and Genetic Mechanism of Geothermal Water in the Northern Jinan Region

by Zongjun Gao, Mengyuan Hao, Jiutan Liu, Qiang Li, Menghan Tan and Yiru Niu

Energies 2023, 16(22), 7658; https://doi.org/10.3390/en16227658 - 19 Nov 2023

Viewed by 966

Abstract

Geothermal water (GW) resources are highly valued as clean, renewable energy sources. In this study, a comprehensive analysis of water chemistry and isotope data from 25 GW samples was conducted to gain insights into the hydrochemical characteristics and formation mechanisms of the GW [...] Read more.

Geothermal water (GW) resources are highly valued as clean, renewable energy sources. In this study, a comprehensive analysis of water chemistry and isotope data from 25 GW samples was conducted to gain insights into the hydrochemical characteristics and formation mechanisms of the GW in the northern Jinan region (NJR). Statistical analysis and hydrochemical methods were employed for relevant analysis. The findings reveal that the GW in the NJR exhibits high salinity, with an average total dissolved solids (TDS) concentration of 9009.00 mg/L. The major ions identified are Na⁺ and Cl⁻, with mean concentrations of 2829.73 mg/L and 4425.77 mg/L, respectively, resulting in a hydrochemical type of Cl⁻Na. The analysis of δ²H and δ¹⁸O isotopes indicates that the GW originates from atmospheric precipitation that undergoes deep cycling and interaction with older groundwater. The composition of ³H suggests that the GW in the NJR is a mixture of waters, while radiocarbon dating (¹⁴C) suggests that the recharge of the GW may have occurred in the late Pleistocene era. The GW in the NJR is classified as partially equilibrated waters. The temperature range of geothermal reservoirs is 57.13 to 99.74 °C. The hydrochemical components primarily result from water–rock interactions, including silicate weathering, cation exchange, as well as carbonate weathering and the dissolution of halite and gypsum. Moreover, taking into account the hydrogeological conditions, hydrochemistry, and isotope analysis, a conceptual model of the geothermal reservoir in the NJR was developed. The research findings serve as a valuable reference and foundation for the development and utilization of geothermal resources in the Jinan region. These originate from the Taiyi mountains in the south or the Taihang mountains in the west, and experience deep circulation and long runoff times. This study provides a reference for the sustainable development and utilization of regional geothermal resources. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1
<p>Map of Location and distribution of geothermal wells (<b>a</b>), pre-Neogene geological (<b>b</b>) and geological cross section (<b>c</b>).</p> Full article ">Figure 2
<p>Piper diagram of GW sample in NJR.</p> Full article ">Figure 3
<p>Relationship between δD−δ¹⁸O in deep GW in NJR.</p> Full article ">Figure 4
<p>Na-K-Mg Giggenbach diagram with GW samples in NJR.</p> Full article ">Figure 5
<p>Schoeller diagram of GW samples.</p> Full article ">Figure 6
<p>Correlation matrix of GW in northern Jinan.</p> Full article ">Figure 7
<p>Gibbs diagram of deep GW samples in Northern Jinan. (<b>a</b>) Relationship between TDS and Na⁺/(Na⁺+Ca²⁺). (<b>b</b>) Relationship between TDS and Cl⁻/(Cl⁻+HCO3⁻).</p> Full article ">Figure 8
<p>Binary scatter plot of major ion ratios in deep GW in northern Jinan. (<b>a</b>) Relationship between the ratios of Na⁺ and Cl⁻. (<b>b</b>) Relationship between the ratios of Ca²⁺+Mg²⁺ and SO₄²⁻+HCO₃⁻. (<b>c</b>) Relationship between the ratios of Ca²⁺ and SO₄²⁻. (<b>d</b>) Relationship between the ratios of Cl⁻-Na⁺-K⁺ and Ca²⁺+Mg²⁺-HCO₃⁻-SO₄²⁻.</p> Full article ">Figure 9
<p>SI values for relevant minerals from deep GW in northern Jinan.</p> Full article ">Figure 10
<p>Conceptual model of geothermal field in the NJR.</p> Full article ">

13 pages, 587 KiB  

Open AccessArticle

Protecting Cape Town’s Groundwater from Fuel Stations: An In-Depth Analysis of Regulatory Requirements

by Eden Alexandre Nsimba, Ntokozo Malaza and Thandazile Marazula

Sustainability 2023, 15(20), 15135; https://doi.org/10.3390/su152015135 - 22 Oct 2023

Viewed by 1761

Abstract

In the face of mounting water supply challenges, Cape Town has increasingly turned to alternative sources, like groundwater. However, the utilisation of groundwater carries inherent risks, particularly the contamination stemming from land-based activities, such as fuel stations. Leaks from underground tanks at these [...] Read more.

In the face of mounting water supply challenges, Cape Town has increasingly turned to alternative sources, like groundwater. However, the utilisation of groundwater carries inherent risks, particularly the contamination stemming from land-based activities, such as fuel stations. Leaks from underground tanks at these stations represent a major global cause of groundwater pollution, and Cape Town is no exception. To safeguard public health and mitigate potential harm, it is imperative to examine the legal regulations governing fuel station development, assess measures for controlling their environmental impacts and evaluate strategies for managing the associated risks. This study aims to provide an exhaustive review of the regulatory framework concerning the environmental impacts of fuel stations, focusing on groundwater protection in Cape Town. A combination of desk research and interviews was employed to gather and analyse data. The findings show a deficiency in precautionary measures for safeguarding groundwater near fuel stations. Consequently, through this study, the existing legal framework’s effectiveness is called into question, with this study suggesting actions to address these identified shortcomings. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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<p>This graph shows that fuel stations account for 88% of the contaminated land registered in the National Contaminated Land Register for the Western Cape.</p> Full article ">Figure 2
<p>Elements to consider for an integrated framework for fuel stations.</p> Full article ">

18 pages, 13736 KiB  

Open AccessArticle

Response Characteristics and Water Inflow Prediction of Complex Groundwater Systems under High-Intensity Coal Seam Mining Conditions

by Zhaolai Hua, Yao Zhang, Shihao Meng, Lu Wang, Xuejun Wang, Yang Lv, Jinming Li, Shaofeng Ren, Han Bao, Zhihao Zhang, Linger Zhao and Yifan Zeng

Water 2023, 15(19), 3376; https://doi.org/10.3390/w15193376 - 26 Sep 2023

Cited by 3 | Viewed by 1370

Abstract

With the gradual improvement in coal mining efficiency, the disturbance of groundwater systems caused by high-intensity mining also increases, leading to challenges in maintaining mine safety and protecting water resources in mining areas. How to accurately describe the dynamic changes in the groundwater [...] Read more.

With the gradual improvement in coal mining efficiency, the disturbance of groundwater systems caused by high-intensity mining also increases, leading to challenges in maintaining mine safety and protecting water resources in mining areas. How to accurately describe the dynamic changes in the groundwater system under mining and quantitatively predict mine water inflow are currently major problems to be addressed. Based on a full analysis of the response characteristics of a groundwater system to the extraction disturbance, this paper presents a new method to establish a mine hydrogeological conceptual model that can accurately represent the water inrush process. The unstructured-grid package of MODFLOW is used to accurately characterize the formation structure and finally make accurate water inflow predictions. Taking the Caojiatan coal mine in Shaanxi Province, China, as an example, a numerical model of unstructured water inflow is established, and the changes in the water inflow source and intensity are quantitatively evaluated. Compared with the traditional water inflow prediction method, the prediction accuracy of the new model is improved by 12–17%, which is achieved by detailing the response of the complex groundwater system under high-intensity mining conditions. The method presented in this paper has great significance and applicatory value for obtaining a comprehensive understanding of the disturbance characteristics of human underground engineering activities (e.g., coal mining) on groundwater systems, as well as accurately predicting water inflow. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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<p>Location of Caojiatan well field and distribution map of laterite aquifer.</p> Full article ">Figure 2
<p>A-A’ typical profile view.</p> Full article ">Figure 3
<p>Conceptual hydrogeological model.</p> Full article ">Figure 4
<p>Measured profile of the height of the water-bearing fracture zone in the inclined direction of 122107 working face (LD-1, LD-2).</p> Full article ">Figure 5
<p>Distribution of water inflow curve for the 122109working face (measured data from the working face).</p> Full article ">Figure 6
<p>Schematic diagram of the hydrogeological conceptual model: three-dimensional structural model; hydrogeological joint profile. (<b>a</b>) three-dimensional structure of the model and (<b>b</b>) the hydrogeological cross-section map.</p> Full article ">Figure 6 Cont.
<p>Schematic diagram of the hydrogeological conceptual model: three-dimensional structural model; hydrogeological joint profile. (<b>a</b>) three-dimensional structure of the model and (<b>b</b>) the hydrogeological cross-section map.</p> Full article ">Figure 7
<p>Schematic diagram of unstructured grid division of the second layer of laterite aquifer.</p> Full article ">Figure 8
<p>Composite monthly average rainfall map of the study area (these data are derived from the local meteorological services).</p> Full article ">Figure 9
<p>Distribution of the stable flow field in the weathered bedrock aquifer of the 12th western panel.</p> Full article ">Figure 10
<p>Aquifer parameter zoning (Quaternary aquifer).</p> Full article ">Figure 11
<p>Aquifer parameter zoning (weathered bedrock aquifer).</p> Full article ">Figure 12
<p>Water level fitting curve of FHS-1 hydropore pumping test.</p> Full article ">Figure 13
<p>Water level fitting curve of FHS-2 hydropore pumping test.</p> Full article ">Figure 14
<p>Forecast of mine water inflow.</p> Full article ">

15 pages, 5483 KiB  

Open AccessArticle

Investigating the Potential Impact on Shallow Groundwater Quality of Oily Wastewater Injection in Deep Petroleum Reservoirs: A Multidisciplinary Evaluation at the Val d’Agri Oilfield (Southern Italy)

by Pietro Rizzo, Antonio Bucci, Pamela Monaco, Anna Maria Sanangelantoni, Gino Naclerio, Mattia Rossi, Paola Iacumin, Federica Bianchi, Claudio Mucchino, Nicolò Riboni, Dario Avagliano, Francesco Coraggio, Antonella Caputi and Fulvio Celico

Sustainability 2023, 15(12), 9161; https://doi.org/10.3390/su15129161 - 6 Jun 2023

Viewed by 1918

Abstract

The increase in oil production from petroleum reservoirs has led to studies examining the effects of these activities on groundwater quality. Oily wastewater associated with oil production is often reinjected through abandoned wells into the unproductive portions of the reservoir to avoid its [...] Read more.

The increase in oil production from petroleum reservoirs has led to studies examining the effects of these activities on groundwater quality. Oily wastewater associated with oil production is often reinjected through abandoned wells into the unproductive portions of the reservoir to avoid its discharge on the surface. The reinjection process is designed to be environmentally friendly and to exclude direct interactions between injected fluids and the surrounding groundwater; nevertheless, the evaluation of the compatibility between this process and the protection of the surrounding environment is of utmost importance when oilfields are located within sensitive and protected areas. The present work aimed to evaluate the impact of the oily wastewater reinjection into a long-term and high-rate disposal well in the Val d’Agri oilfield (Southern Italy). Previous preliminary investigations carried out at the study site led researchers to hypothesize the possible hydrocarbon contamination of the shallower aquifer caused by reinjection well integrity issues. Our strategy is based on an integrated and multidisciplinary approach involving isotopic (stable isotopes ²H and ¹⁸O), chemical, and microbiological (characterization of bacterial and archaeal communities) analyses. After a comprehensive and meticulous examination of the research data, it has been ascertained that significant discrepancies exist between the shallow and reinjection water systems. This allowed us to clarify the area’s complex flow dynamics and exclude hydrocarbon contamination of spring waters caused by the reinjection process. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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<p>Schematic map of the Agri Valley showing the location of the study area (modified by Rizzo et al. [<a href="#B21-sustainability-15-09161" class="html-bibr">21</a>]).</p> Full article ">Figure 2
<p>Geological map and monitored springs/streams (see location in <a href="#sustainability-15-09161-f001" class="html-fig">Figure 1</a>) (modified by Rizzo et al. [<a href="#B21-sustainability-15-09161" class="html-bibr">21</a>]).</p> Full article ">Figure 3
<p>O versus δ²H relationship in water samples collected from rainwater samplers at PCLRs, at the Pz1, and the oily wastewaters before the reinjection. Linear RW is the local meteoric water line obtained by local rainwater. MWL is the Meteoric Water Line of Southern Italy obtained from Longinelli and Selmo [<a href="#B44-sustainability-15-09161" class="html-bibr">44</a>].</p> Full article ">Figure 4
<p>Bacterial (<b>a</b>) and archaeal (<b>b</b>) 16S rDNA PCR-DGGE community profiles of PCLRs (sample codes 83 and 84) before being tampered with (April 2016), other springs (sample codes P001, P002, P006, 89BIS, 90, 147, 148, 153, and 161), and stream monitoring points (sample codes F001, F002, F003, F004, and F005).</p> Full article ">Figure 5
<p>Cluster analysis of bacterial (<b>a</b>) and archaeal (<b>b</b>) 16S rDNA PCR-DGGE profiles of PCLRs (sample codes 83 and 84) before being tampered with (April 2016), other springs (sample codes P001, P002, P006, 89BIS, 90, 147, 148, 153, and 161), and stream monitoring points (sample codes F001, F002, F003, F004, and F005) (Dice coefficient with the UPGMA clustering algorithm). Similarity values are shown.</p> Full article ">Figure 6
<p>Rarefaction curves with Shannon index for <span class="html-italic">Bacteria</span> domain.</p> Full article ">Figure 7
<p>Genus level bacterial community composition.</p> Full article ">

15 pages, 17378 KiB  

Open AccessArticle

Estimation of Nitrate Background Value in Groundwater under the Long-Term Human Impact

by Patricia Buškulić, Jelena Parlov, Zoran Kovač and Zoran Nakić

Hydrology 2023, 10(3), 63; https://doi.org/10.3390/hydrology10030063 - 4 Mar 2023

Cited by 2 | Viewed by 1879

Abstract

This study demonstrates an approach to estimate the background value of nitrate as a basis for better groundwater management and protection in areas under long-term human impact. The aim was to determine the ambient background value (ABV) of nitrate in the catchment area [...] Read more.

This study demonstrates an approach to estimate the background value of nitrate as a basis for better groundwater management and protection in areas under long-term human impact. The aim was to determine the ambient background value (ABV) of nitrate in the catchment area of the Velika Gorica well field, a hydrogeologically homogeneous area within the Zagreb aquifer. ABVs are determined using four well-known model-based objective methods (the iterative 2-σ technique, IT; the calculated distribution function, CDF; the cumulative frequency curve, CFC; and the probability plot, PP), while simultaneously testing the reliability of the results of each method. If the results are not statistically significant, data selection is performed. The results show that using data without selection can lead to statistically non-significant ABVs, but with the additional selection of data, a statistically non-significant result became a statistically significant one. In summary, all final ABVs must be statistically significant and determined using as large a data set as possible. Reducing the size of the data set is acceptable only in the case of a statistically non-significant result. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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<p>Research area.</p> Full article ">Figure 2
<p>The annual precipitation (<b>a</b>) and the average monthly precipitation (<b>b</b>) with average, minimum and maximum air temperature; depth to groundwater (<b>c</b>) and groundwater levels (<b>d</b>) for the period 2001 to 2020.</p> Full article ">Figure 3
<p>Four different methods to estimate ABV of nitrate for data without selection: (<b>a</b>) IT: lower background value: 11.8; D &lt; D_crit, (<b>b</b>) CDF: lower background value: 8.3; D &gt; D_crit, (<b>c</b>) CFC: background value: 7.5 and (<b>d</b>) PP: background value: 7.1. Arrow indicates first inflection point that separates background and non-background population.</p> Full article ">Figure 4
<p>Histograms and normal distribution curves. Normally distributed data are bolded.</p> Full article ">Figure 5
<p>Four different methods to estimate ABV of nitrate for selected NON-ND data: (<b>a</b>) IT: lower background value: 13.2; D &lt; D_crit, (<b>b</b>) CDF: lower background value: 7.2; D &lt; D_crit, (<b>c</b>) CFC: background value: 7.3 and (<b>d</b>) PP: background value: 6.9. Arrow indicates first inflection point that separates background and non-background population.</p> Full article ">

20 pages, 8031 KiB  

Open AccessArticle

Hydrogeochemical Characteristics, Water Quality, and Human Health Risks of Groundwater in Wulian, North China

by Min Wang, Wenxiu Zhang, Peng Yang, Jianguo Feng, Ruilin Zhang, Zongjun Gao, Hongjie Jin, Xiaoyu Song and Xiaobing Gao

Water 2023, 15(2), 359; https://doi.org/10.3390/w15020359 - 15 Jan 2023

Cited by 6 | Viewed by 2537

Abstract

Groundwater shortage and pollution are critical issues of global concern. In Wulian County, a typical hilly area, groundwater is the main source of water supply. This study investigates the current situation of groundwater pollution in Wulian City through the analysis of groundwater water [...] Read more.

Groundwater shortage and pollution are critical issues of global concern. In Wulian County, a typical hilly area, groundwater is the main source of water supply. This study investigates the current situation of groundwater pollution in Wulian City through the analysis of groundwater water chemistry characteristics, water quality evaluation, and health risk evaluation. After the analysis of the controlling factors of chemical components in groundwater and the analysis of ion sources, the main ion sources in groundwater were determined. The results showed that the major cations in groundwater were Ca²⁺ and Na⁺ and the major anions were HCO₃⁻ and SO₄²⁻. Nevertheless, NO₃⁻ exceeded the standard to different degrees in pore water (PW), fissure pore water (FPW), and fissure water (FW). The minimum NO₃⁻ concentration exceeded the standard in FW. Under the influence of rock weathering and salt rock dissolution, the main hydrochemical types of groundwater were the HCO₃-Ca, HCO₃-Ca·Mg, and SO₄·Cl-Ca·Mg types. According to the water quality evaluation and health risk assessment, the FW area in the south had the highest water quality, where Class I water appeared and potable water was more widely distributed. The PW and FPW areas in the north had lower water quality, with higher health risks. Category V water gradually appeared in the FPW area, which is not suitable as a water supply source. Factor analysis and ion ratio analysis showed that the study area is strongly affected by anthropogenic factors. These research methods have important reference value to the research of groundwater pollution status. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1

Figure 1
<p>Geographical locations of the study area and sampling sites for three different types of groundwater.</p> Full article ">Figure 2
<p>Box plots of the chemical contents of different groundwater types. (<b>a</b>) Na⁺ box plot; (<b>b</b>) K⁺ box plot; (<b>c</b>) Ca²⁺ box plot; (<b>d</b>) Mg²⁺ box plot; (<b>e</b>) CI⁻ box plot; (<b>f</b>) SO₄²⁻ box plot; (<b>g</b>) HCO₃⁻ box plot; (<b>h</b>) NO₃⁻ box plot; (<b>i</b>) TDS box plot; (<b>j</b>) TH box plot; (<b>k</b>) pH box plot.</p> Full article ">Figure 3
<p>Piper diagram showing the hydrochemical characteristics of groundwater in the Wulian area.</p> Full article ">Figure 4
<p>Radar maps of water quality of different groundwater types. (<b>a</b>) PW, (<b>b</b>) FPW, (<b>c</b>) FW.</p> Full article ">Figure 5
<p>Health risk index distribution maps for adults and children.</p> Full article ">Figure 6
<p>Correlation plots between ionic components of three groundwater types.</p> Full article ">Figure 7
<p>Gibbs plots of factors influencing the chemical characterization of groundwater in the Wulian. (TDS vs. Na⁺/(Na⁺ + Ca²⁺) (<b>a</b>) TDS vs. Cl⁻/(Cl⁻ + HCO₃⁻) (<b>b</b>)).</p> Full article ">Figure 8
<p>Analysis of the ion ratio in groundwater. (<b>a</b>) Cl⁻ vs. Na⁺; (<b>b</b>) Mg²⁺ vs. Ca²⁺; (<b>c</b>) Ca²⁺ + Mg²⁺ − SO₄²⁻ − HCO₃⁻ vs. Na⁺ + K + -Cl⁻; (<b>d</b>) NO₃⁻/Cl⁻ vs. Cl⁻.</p> Full article ">Figure 9
<p>Factor scores of the three groundwater types. (The square indicates that the factor score value is between 25% and 75%).</p> Full article ">

17 pages, 5860 KiB  

Open AccessArticle

Numerical Simulation of the Wormhole Propagation in Fractured Carbonate Rocks during Acidization Using a Thermal-Hydrologic-Mechanics-Chemical Coupled Model

by Piyang Liu, Chaoping Huang, Lijing Jia, Weijing Ji, Zhao Zhang and Kai Zhang

Water 2022, 14(24), 4117; https://doi.org/10.3390/w14244117 - 16 Dec 2022

Cited by 1 | Viewed by 2791

Abstract

Acidizing is a widely adopted approach for stimulating carbonate reservoirs. The two-scale continuum (TSC) model is the most widely used model for simulating the reactive process in a carbonate reservoir during acidizing. In realistic cases, there are overburden pressure and pore pressure at [...] Read more.

Acidizing is a widely adopted approach for stimulating carbonate reservoirs. The two-scale continuum (TSC) model is the most widely used model for simulating the reactive process in a carbonate reservoir during acidizing. In realistic cases, there are overburden pressure and pore pressure at present. When the injected acid reacts with the rock, the dissolution of the rock and the consumption of the acid in the pore will break the mechanical balance of the rock. Many experimental studies show that cores after acidizing have lower strength. However, it is still not clear how the deformation of rocks by the change of ground stress influences the acidizing dynamics. For fractured carbonate reservoirs, fractures play a leading role in the flow of injected acid, which preferentially flows into the fractures and dissolves the fracture walls. The effect of the combined action of rock mechanical balance broken and fracture wall dissolution on the formation of wormholes in fractured carbonate reservoirs remains to be studied. To address the above-mentioned issues, a thermal-hydrologic-mechanical-chemical coupled model is presented based on the TSC model for studying the wormhole propagation in fractured carbonate reservoirs under practical conditions. Linear and radial flow cases are simulated to investigate the influences of fracture distribution, reaction temperature, and effective stress on acidizing dynamics. The simulation results show that more wormhole branches are formed by acidizing if the fractures are perpendicular to the flow direction of acid. Temperature is a key parameter affecting the acidification dissolution patterns, so the influence of temperature cannot be ignored during the acidification design. As the effective stress of the formation increases, the diameter of the wormhole gradually decreases, and the branching decreases. More acid is needed for the same stimulation result under higher effective stress. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1

Figure 1
<p>Porosity fields show the impact of fracture orientation on wormhole structures (<b>A</b>) Linear case, (<b>B</b>) Radial case and at different fracture dips: (<b>a</b>) <math display="inline"><semantics> <msup> <mn>30</mn> <mo>∘</mo> </msup> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <msup> <mn>60</mn> <mo>∘</mo> </msup> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <msup> <mn>90</mn> <mo>∘</mo> </msup> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <msup> <mn>120</mn> <mo>∘</mo> </msup> </semantics></math> (<math display="inline"><semantics> <mrow> <mo>−</mo> <msup> <mn>60</mn> <mo>∘</mo> </msup> </mrow> </semantics></math>), (<b>e</b>) <math display="inline"><semantics> <msup> <mn>150</mn> <mo>∘</mo> </msup> </semantics></math> (<math display="inline"><semantics> <mrow> <mo>−</mo> <msup> <mn>30</mn> <mo>∘</mo> </msup> </mrow> </semantics></math>).</p> Full article ">Figure 2
<p>The effect of fracture dip on dimensionless breakthrough volumes corresponds to the dissolution structures in <a href="#water-14-04117-f001" class="html-fig">Figure 1</a> column (A).</p> Full article ">Figure 3
<p>Effect of fracture length on wormhole structures in linear acidizing simulation.</p> Full article ">Figure 4
<p>Effect of fracture length on wormhole structures in radial acidizing stimulation.</p> Full article ">Figure 5
<p>The dimensionless breakthrough volumes correspond to the dissolution structures in <a href="#water-14-04117-f003" class="html-fig">Figure 3</a> and <a href="#water-14-04117-f004" class="html-fig">Figure 4</a>.</p> Full article ">Figure 6
<p>Influence of fracture density on wormhole structures, the number of fractures: (<b>A</b>) 12; (<b>B</b>) 17; (<b>C</b>) 30.</p> Full article ">Figure 7
<p>Influence of fracture density on wormhole structures, the number of fractures: (<b>A</b>) 20; (<b>B</b>) 35; (<b>C</b>) 50.</p> Full article ">Figure 8
<p>Comparison of dissolution structures for non-isothermal and isothermal cases in linear acidizing simulation.</p> Full article ">Figure 9
<p>Comparison of dissolution structures for non-isothermal and isothermal cases in radial acidizing stimulation.</p> Full article ">Figure 10
<p>Comparison of dissolution structures at different effective stress: (<b>A</b>) <math display="inline"><semantics> <mrow> <mi>σ</mi> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math> MPa, (<b>B</b>) <math display="inline"><semantics> <mrow> <mi>σ</mi> <mo>=</mo> <mn>15</mn> </mrow> </semantics></math> MPa, (<b>C</b>) <math display="inline"><semantics> <mrow> <mi>σ</mi> <mo>=</mo> <mn>30</mn> </mrow> </semantics></math> MPa, (<b>D</b>) <math display="inline"><semantics> <mrow> <mi>σ</mi> <mo>=</mo> <mn>45</mn> </mrow> </semantics></math> MPa and at different injection rates: <math display="inline"><semantics> <mrow> <mn>1</mn> <mo>/</mo> <mi>D</mi> <mi>a</mi> </mrow> </semantics></math> = (<b>a</b>) <math display="inline"><semantics> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>6</mn> </mrow> </msup> </semantics></math> (<b>b</b>) <math display="inline"><semantics> <mrow> <mn>2</mn> <mo>×</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>6</mn> </mrow> </msup> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>4</mn> </mrow> </msup> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <mn>0.005</mn> </mrow> </semantics></math>, (<b>e</b>) <math display="inline"><semantics> <mrow> <mn>0.05</mn> </mrow> </semantics></math>.</p> Full article ">Figure 11
<p>Comparison of dissolution structures at different effective stress: (<b>A</b>) <math display="inline"><semantics> <mrow> <mi>σ</mi> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math> MPa, (<b>B</b>) <math display="inline"><semantics> <mrow> <mi>σ</mi> <mo>=</mo> <mn>15</mn> </mrow> </semantics></math> MPa, (<b>C</b>) <math display="inline"><semantics> <mrow> <mi>σ</mi> <mo>=</mo> <mn>30</mn> </mrow> </semantics></math> MPa, (<b>D</b>) <math display="inline"><semantics> <mrow> <mi>σ</mi> <mo>=</mo> <mn>45</mn> </mrow> </semantics></math> MPa and at different injection rates: <math display="inline"><semantics> <mrow> <mn>1</mn> <mo>/</mo> <mi>D</mi> <mi>a</mi> </mrow> </semantics></math> = (<b>a</b>) <math display="inline"><semantics> <mrow> <mn>0.00075</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mn>0.0225</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mn>0.075</mn> </mrow> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <mn>0.75</mn> </mrow> </semantics></math>.</p> Full article ">Figure 12
<p>Comparison of the <math display="inline"><semantics> <mrow> <mi>P</mi> <msub> <mi>V</mi> <mrow> <mi>B</mi> <mi>T</mi> </mrow> </msub> </mrow> </semantics></math> calculated under different effective stress conditions.</p> Full article ">

12 pages, 1776 KiB  

Open AccessArticle

Study of Single Fracture Seepage Characteristics of Fault-Filled Materials Based on CT Technology

by Wenbin Sun, Shaoyu Wang, Faxu Dong and Yandong Xue

Water 2022, 14(22), 3679; https://doi.org/10.3390/w14223679 - 14 Nov 2022

Cited by 2 | Viewed by 1742

Abstract

In order to study the matrix loss process and skeleton seepage law in the fracture of the fault rock, the three-dimensional model of the skeletal rock sample of the fault rock was obtained by CT scan, and the porous media seepage model was [...] Read more.

In order to study the matrix loss process and skeleton seepage law in the fracture of the fault rock, the three-dimensional model of the skeletal rock sample of the fault rock was obtained by CT scan, and the porous media seepage model was established with different structural types of natural fractures, and the flow rate and pressure distribution law of the seepage in the fracture was obtained by FLUENT software simulation. The results show that: the seepage under different pressure conditions is approximately the same, and the velocity increases continuously with the increase in pressure; The water seepage in different directions of the fracture channels under the same pressure conditions is not exactly the same, which is caused by the different microstructures of the pores. For the pressure distribution, it gradually decreases along the direction of water seepage, and for the speed distribution, it shows the law of changing from large to small and then increasing. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1

Figure 1
<p>Mine Location Map: (<b>a</b>) Map of China. (<b>b</b>) Map of Shandong. (<b>c</b>) Diagram of Anju Coal Mine in Jining Mining District.</p> Full article ">Figure 2
<p>CT scan preprocessing.</p> Full article ">Figure 3
<p>z forward inlet pressure cloud map: (<b>a</b>) 0.1 Mpa pressure cloud map. (<b>b</b>) 0.5 Mpa pressure cloud map. (<b>c</b>) 1 Mpa pressure cloud map. (<b>d</b>) 3 Mpa pressure cloud map. (<b>e</b>) 5 Mpa pressure cloud map. (<b>f</b>) 10 Mpa pressure cloud map.</p> Full article ">Figure 4
<p>z forward inlet velocity vector diagram:(<b>a</b>) 0.1 Mpa speed vector. (<b>b</b>) 0.5 Mpa speed vector. (<b>c</b>) 1 Mpa speed vector. (<b>d</b>) 3 Mpa speed vector. (<b>e</b>) 5 Mpa speed vector. (<b>f</b>) 10 Mpa speed vector illustration.</p> Full article ">Figure 5
<p>z negative inlet pressure cloud map: (<b>a</b>) 0.1 Mpa pressure cloud map. (<b>b</b>) 0.5 Mpa pressure cloud map. (<b>c</b>) 1 Mpa pressure cloud map. (<b>d</b>) 3 Mpa pressure cloud map. (<b>e</b>) 5 Mpa pressure cloud map. (<b>f</b>) 10 Mpa pressure cloud map.</p> Full article ">Figure 5 Cont.
<p>z negative inlet pressure cloud map: (<b>a</b>) 0.1 Mpa pressure cloud map. (<b>b</b>) 0.5 Mpa pressure cloud map. (<b>c</b>) 1 Mpa pressure cloud map. (<b>d</b>) 3 Mpa pressure cloud map. (<b>e</b>) 5 Mpa pressure cloud map. (<b>f</b>) 10 Mpa pressure cloud map.</p> Full article ">Figure 6
<p>z negative inlet velocity vector diagram:(<b>a</b>) 0.1 Mpa speed vector. (<b>b</b>) 0.5 Mpa speed vector. (<b>c</b>) 1 Mpa speed vector. (<b>d</b>) 3 Mpa speed vector. (<b>e</b>) 5 Mpa speed vector. (<b>f</b>) 10 Mpa speed vector.</p> Full article ">Figure 7
<p>Velocity change diagram under different inlet pressure conditions.</p> Full article ">Figure 8
<p>The 3 Mp pressure cloud and speed vector illustration: (<b>a</b>) fracture mesh model. (<b>b</b>) pressure cloud map. (<b>c</b>) speed vector illustration.</p> Full article ">Figure 9
<p>The 3 Mp pressure cloud and speed vector illustration: (<b>a</b>) fracture grid motion trajectory. (<b>b</b>) z forward motion trajectory diagram. (<b>c</b>) z negative motion trajectory diagram.</p> Full article ">

19 pages, 5118 KiB  

Open AccessArticle

Characteristics and Controlling Factors of Groundwater Hydrochemistry in Dongzhi Tableland Area of the Loess Plateau of Eastern Gansu—A Case Study of Ning County Area, North China

by Mengnan Zhang, Shuangbao Han, Yushan Wang, Zhan Wang, Haixue Li, Xiaoyan Wang, Jiutan Liu, Changsuo Li and Zongjun Gao

Water 2022, 14(22), 3601; https://doi.org/10.3390/w14223601 - 8 Nov 2022

Cited by 6 | Viewed by 1793

Abstract

Groundwater plays an irreplaceable role in all aspects of the Loess Plateau. In this study, the loess phreatic water (LPW) and bedrock phreatic water (BPW) in the Ning County area (NCA) were sampled and analyzed, and the characteristics and controlling factors of groundwater [...] Read more.

Groundwater plays an irreplaceable role in all aspects of the Loess Plateau. In this study, the loess phreatic water (LPW) and bedrock phreatic water (BPW) in the Ning County area (NCA) were sampled and analyzed, and the characteristics and controlling factors of groundwater were determined by using statistical analysis, hydrochemical methods, and hydrogeochemical simulation. The results indicated that the groundwater in the NCA was alkaline as a whole, and the average pH values of LPW and BPW were 8.1 and 7.8, respectively. The mean values of TDS concentrations of LPW and BPW were 314.9 mg/L and 675.3 mg/L, and the mean values of TH contents were 194.6 mg/L and 286.6 mg/L, respectively, which were mainly divided into hard fresh water. The Piper diagram illustrated that the hydrochemical type of groundwater in the NCA was mainly the HCO₃·Ca type. The main recharge source of groundwater was atmospheric precipitation, and it was affected by evaporation to a certain extent. The linear relationships of δ¹⁸O and δ²H of LPW and BPW were δ²H = 6.998δ¹⁸O − 3.802 (R² = 0.98) and δ²H = 6.283δ¹⁸O − 10.536 (R² = 0.96), respectively. Hydrochemical analysis indicated that the groundwater in the NCA was mainly controlled by rock weathering and cation exchange. BPW was affected by the dissolution of gypsum. The possible mineral phases were identified on the basis of the main soluble minerals in the aquifer, and hydrogeochemical reverse simulations were performed. The dissolution of calcite, illite, and hornblende, and the precipitation of dolomite, plagioclase, and microcline occurred on both the LPW and BPW pathways. Full article

(This article belongs to the Topic Human Impact on Groundwater Environment)

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Figure 1

Figure 1
<p>Location map of the study area and groundwater sampling points.</p> Full article ">Figure 2
<p>Regional meteorologic map.</p> Full article ">Figure 3
<p>Stereoscopic sketch map of east–west geomorphology and geology in the Longdong basin of eastern Gansu.</p> Full article ">Figure 4
<p>Box diagram of the main chemical components of groundwater.</p> Full article ">Figure 4 Cont.
<p>Box diagram of the main chemical components of groundwater.</p> Full article ">Figure 5
<p>Piper diagram of groundwater hydrochemistry.</p> Full article ">Figure 6
<p>Scatter diagram of TH vs. TDS (<b>a</b>) and SO₄²⁻ vs. Cl⁻ + HCO₃⁻ (<b>b</b>) of groundwater samples in the study area.</p> Full article ">Figure 7
<p>Gibbs diagram of groundwater hydrochemistry TDS vs. Na⁺/(Na⁺+Ca²⁺) (<b>a</b>) TDS vs. Cl⁻/(Cl⁻+HCO₃⁻) (<b>b</b>).</p> Full article ">Figure 8
<p>The relationship between the ion ratios of the main chemical components in the groundwater. Na⁺ vs. Cl⁻ (<b>a</b>), Ca²⁺ vs. HCO₃⁻ (<b>b</b>), Mg²⁺+Ca²⁺ vs. HCO₃⁻ (<b>c</b>), Mg²⁺ vs. Ca²⁺ (<b>d</b>), SO₄²⁻ vs. Ca²⁺ (<b>e</b>) and Mg²⁺+Ca²⁺ vs. SO₄²⁻+HCO₃⁻ (<b>f</b>).</p> Full article ">Figure 9
<p>Diagrams of (<b>a</b>) K⁺ + Na⁺ − Cl⁻ vs. Mg²⁺ + Ca²⁺ − HCO₃⁻ − SO₄²⁻ and (<b>b</b>) CAI-1 vs. CAI-2.</p> Full article ">Figure 10
<p>δ²H-δ¹⁸O relationship diagram of groundwater.</p> Full article ">

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