Water

20 pages, 6441 KiB

Open AccessArticle

A Performance Comparison Study on Climate Prediction in Weifang City Using Different Deep Learning Models

by Qingchun Guo, Zhenfang He, Zhaosheng Wang, Shuaisen Qiao, Jingshu Zhu and Jiaxin Chen

Water 2024, 16(19), 2870; https://doi.org/10.3390/w16192870 - 9 Oct 2024

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Climate change affects the water cycle, water resource management, and sustainable socio-economic development. In order to accurately predict climate change in Weifang City, China, this study utilizes multiple data-driven deep learning models. The climate data for 73 years include monthly average air temperature [...] Read more.

Climate change affects the water cycle, water resource management, and sustainable socio-economic development. In order to accurately predict climate change in Weifang City, China, this study utilizes multiple data-driven deep learning models. The climate data for 73 years include monthly average air temperature (MAAT), monthly average minimum air temperature (MAMINAT), monthly average maximum air temperature (MAMAXAT), and monthly total precipitation (MP). The different deep learning models include artificial neural network (ANN), recurrent NN (RNN), gate recurrent unit (GRU), long short-term memory neural network (LSTM), deep convolutional NN (CNN), hybrid CNN-GRU, hybrid CNN-LSTM, and hybrid CNN-LSTM-GRU. The CNN-LSTM-GRU for MAAT prediction is the best-performing model compared to other deep learning models with the highest correlation coefficient (R = 0.9879) and lowest root mean square error (RMSE = 1.5347) and mean absolute error (MAE = 1.1830). These results indicate that The hybrid CNN-LSTM-GRU method is a suitable climate prediction model. This deep learning method can also be used for surface water modeling. Climate prediction will help with flood control and water resource management. Full article

(This article belongs to the Section Water and Climate Change)

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25 pages, 20188 KiB

Open AccessArticle

Temperature and Precipitation Change Assessment in the North of Iraq Using LARS-WG and CMIP6 Models

by Sura Mohammed Abdulsahib, Salah L. Zubaidi, Yousif Almamalachy and Anmar Dulaimi

Water 2024, 16(19), 2869; https://doi.org/10.3390/w16192869 - 9 Oct 2024

Viewed by 718

Abstract

Investigating the spatial-temporal evolutionary trends of future temperature and precipitation considering various emission scenarios is crucial for developing effective responses to climate change. However, researchers in Iraq have not treated this issue under CMIP6 in much detail. This research aims to examine the [...] Read more.

Investigating the spatial-temporal evolutionary trends of future temperature and precipitation considering various emission scenarios is crucial for developing effective responses to climate change. However, researchers in Iraq have not treated this issue under CMIP6 in much detail. This research aims to examine the spatiotemporal characteristics of temperature and rainfall in northern Iraq by applying LARS-WG (8) under CMIP6 general circulation models (GCMs). Five GCMs (ACCESS-ESM1-5, CNRM-CM6-1, MPI-ESM1-2-LR, HadGEM3-GC31-LL, and MRI-ESM2-0) and two emissions scenarios (SSP245 and SSP585) were applied to project the upcoming climate variables for the period from 2021 to 2040. The research relied on satellite data from fifteen weather sites spread over northern Iraq from 1985 to 2015 to calibrate and validate the LARS-WG model. Analysis of spatial-temporal evolutionary trends of future temperature and precipitation compared with the baseline period revealed that seasonal mean temperatures will increase throughout the year for both scenarios. However, the SSP585 scenario reveals the highest increase during autumn when the spatial coverage of class (15–20) °C increased from 27.7 to 96.29%. At the same time, the average seasonal rainfall will rise in all seasons for both scenarios except autumn for the SSP585 scenario. The highest rainfall increment percentage is obtained using the SSP585 for class (120–140) mm during winter. The spatial extent of the class increased from 25.49 to 50.19%. Full article

(This article belongs to the Section Water and Climate Change)

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17 pages, 3376 KiB

Open AccessArticle

Estimation of the Potential for Soil and Water Conservation Measures in a Typical Basin of the Loess Plateau, China

by Beilei Liu, Peng Li, Zhanbin Li, Jianye Ma, Zeyu Zhang and Bo Wang

Water 2024, 16(19), 2868; https://doi.org/10.3390/w16192868 - 9 Oct 2024

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Abstract

Abstract: In the context of the large-scale management of the Loess Plateau and efforts to reduce water and sediment in the Yellow River, this study focuses on a typical watershed within the Loess Plateau. The potential for vegetation restoration in the Kuye River [...] Read more.

Abstract: In the context of the large-scale management of the Loess Plateau and efforts to reduce water and sediment in the Yellow River, this study focuses on a typical watershed within the Loess Plateau. The potential for vegetation restoration in the Kuye River Basin is estimated based on the assumption that vegetation cover should be relatively uniform under similar habitat conditions. The potential for terrace restoration is assessed through an analysis of topographic features and soil layer thickness, while the potential for silt dam construction is evaluated by considering various hydrological and geomorphological factors. Based on these assessments, the overall potential for soil erosion control in the watershed is synthesized, providing a comprehensive understanding of target areas for ecological restoration within the Kuye River Basin. The study demonstrates that the areas with the greatest potential for vegetation restoration in the Kuye River Basin are concentrated in the upper and middle reaches of the basin, which are in closer proximity to the river. The total potential for terracing is 1013.85 km², which is primarily distributed across the river terraces, farmlands, and gentle slopes on both sides of the riverbanks. Additionally, the potential for the construction of check dams is 14,390 units. The target areas for terracing measures in the Kuye River Basin are primarily situated in the middle and lower reaches of the basin, which are in closer proximity to the river. Conversely, the target areas for forest, grass, and check dams, as well as other small watershed integrated management measures, are predominantly located in the hill and gully areas on the eastern and southern sides of the basin. The implementation of the gradual ecological construction of the watershed, based on the aforementioned objectives, will facilitate the protection, improvement, and rational utilization of soil, water, and other natural resources within the watershed. Full article

(This article belongs to the Special Issue Soil Erosion and Soil and Water Conservation)

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17 pages, 2248 KiB

Open AccessArticle

The Impact of Digital Technology on Water Resources Management: Evidence from China

by Xiaochun Zhao, Danjie Yang and Ying Zhou

Water 2024, 16(19), 2867; https://doi.org/10.3390/w16192867 - 9 Oct 2024

Viewed by 583

Abstract

Digital technology is gradually emerging as a new driving force in the field of water resources management. In this paper, we conduct a thorough analysis of panel data from 30 provinces in China spanning from 2013 to 2022. Utilizing the fixed-effects model, the [...] Read more.

Digital technology is gradually emerging as a new driving force in the field of water resources management. In this paper, we conduct a thorough analysis of panel data from 30 provinces in China spanning from 2013 to 2022. Utilizing the fixed-effects model, the mediation effect model, a panel threshold model, and a coupling coordination degree model, this study empirically examines the impact of digital technology on water resources management. The findings are as follows: (1) The direct impact of digital technology on water resources management is significantly positive at the 1% level, with notable regional variations. (2) Digital technology improves water management through green innovation. (3) In the process of digital technology promoting water resources management, green innovation exhibits a threshold effect, with an estimated threshold value of 1.840. (4) During the sample period, the national coupling coordination degree of digital technology and water resources management was barely coordinated, showing the following characteristics: Eastern China > Western China > Central China. These research conclusions will offer valuable insights and directions for advancing sustainable water resources management strategies and fostering the deep integration of digital technology and water resources management. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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14 pages, 3603 KiB

Open AccessArticle

Investigating a Century of Rainfall: The Impact of Elevation on Precipitation Changes (Northern Tuscany, Italy)

by Matteo Nigro, Michele Barsanti, Brunella Raco and Roberto Giannecchini

Water 2024, 16(19), 2866; https://doi.org/10.3390/w16192866 - 9 Oct 2024

Viewed by 590

Abstract

Precipitation is crucial for water resource renewal, but climate change alters their frequency and amounts, challenging societies for correct and effective water management. However, modifications of precipitation dynamics appear to be not uniformly distributed, both in space and time. Even in relatively small [...] Read more.

Precipitation is crucial for water resource renewal, but climate change alters their frequency and amounts, challenging societies for correct and effective water management. However, modifications of precipitation dynamics appear to be not uniformly distributed, both in space and time. Even in relatively small areas, precipitation shows the coexistence of positive and negative trends. Local topography seems to be a strong driver of precipitation changes. Understanding precipitation changes and their relationship with local topography is crucial for society’s resilience. Taking advantage of a dense and long-lasting (1920–2019) meteorological monitoring network, we analyzed the precipitation changes over the last century in a sensitive and strategic area in the Mediterranean hotspot. The study area corresponds to northern Tuscany (Italy), where its topography comprises mountain ridges and coastal and river plains. Forty-eight rain gauges were selected with continuous annual precipitation time series. These were analyzed for trends and differences in mean annual precipitation between the stable period of 1921–1970 and the last 30-year 1990–2019. The relationship between precipitation changes and local topography was also examined. The results show the following highlights: (i) A general decrease in precipitation was found through the century, even if variability is marked. (ii) The mountain ridges show the largest decrease in mean annual precipitation. (iii) The precipitation change entity over the last century was not homogenous and was dependent on topography and geographical setting. (iv) A decrease in annual precipitation of up to 400 mm was found for the mountainous sites. Full article

(This article belongs to the Section Hydrology)

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14 pages, 3352 KiB

Open AccessArticle

SEAWAT Scenarios Evaluating Links between the Southern Gabès (TN) Confined Aquifer and the Mediterranean Sea

by Khyria Wederni, Massimiliano Schiavo, Boulbaba Haddaji, Younes Hamed, Salem Bouri and Nicolò Colombani

Water 2024, 16(19), 2865; https://doi.org/10.3390/w16192865 - 9 Oct 2024

Viewed by 442

Abstract

The southern Gabès aquifer in southeastern Tunisia faces significant stress due to unsustainable groundwater extraction. This study employs a SEAWAT model to evaluate groundwater losses, salinization mechanisms, and the interaction between the confined aquifer and the Mediterranean Sea. The model, incorporating well pumping [...] Read more.

The southern Gabès aquifer in southeastern Tunisia faces significant stress due to unsustainable groundwater extraction. This study employs a SEAWAT model to evaluate groundwater losses, salinization mechanisms, and the interaction between the confined aquifer and the Mediterranean Sea. The model, incorporating well pumping rates, regional freshwater inflows from the Matmata Mountain Range, and the Mediterranean Sea boundary, demonstrated high accuracy in simulating hydraulic heads. Findings reveal that regional inflow is only half of the current pumping rate, indicating unsustainable groundwater use. The study also assessed salinity dynamics by modeling the Mediterranean Sea as a constant head and salinity boundary. Results suggest limited exchange between the aquifer and the sea, challenging previous assumptions. While the immediate risks of salinization are low, continued over-extraction could compromise the aquifer’s long-term sustainability. This research highlights the need for stricter local groundwater management, offers insights into regional coastal aquifer interactions, and contributes to global discussions on managing stressed aquifer systems. Full article

(This article belongs to the Section Hydrogeology)

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18 pages, 18581 KiB

Open AccessArticle

Spatial–Temporal Variations in Water Use Efficiency and Its Influencing Factors in the Li River Basin, China

by Yanqi Chu, Xiangling Tang and Xuemei Zhong

Water 2024, 16(19), 2864; https://doi.org/10.3390/w16192864 - 9 Oct 2024

Viewed by 457

Abstract

As a vital indicator for measuring the coupled carbon–water cycle of an ecosystem, water use efficiency (WUE) can also reflect the adaptive capacity of plants in different ecosystems. Located in Southwest China, the Li River Basin has a representative karst landform, and the [...] Read more.

As a vital indicator for measuring the coupled carbon–water cycle of an ecosystem, water use efficiency (WUE) can also reflect the adaptive capacity of plants in different ecosystems. Located in Southwest China, the Li River Basin has a representative karst landform, and the uneven rainfall in the region leads to severe water shortage. In this study, we analyzed the spatial–temporal transformation characteristics of the WUE of the basin and its relationship with different influencing factors from 2001 to 2020 based on a correlation analysis and trend analysis. The main conclusions are as follows: (1) The average value of WUE in the Li River Basin was 1.8251 gC· mm⁻¹·m⁻², and it kept decreasing at a rate of 0.0072 gC· mm⁻¹·m⁻²·a⁻¹ in the past 20 years. With respect to the spatial distribution of the multi-year average of WUE, it exhibits a gradual increasing trend from west to east. (2) Between gross primary productivity (GPP) and evapotranspiration (ET), it was found that ET was the primary influencing factor of WUE. Precipitation was positively correlated with WUE in the Li River Basin, accounting for 67.22% of the total area of the basin. The air temperature was negatively correlated with WUE, and the area was negatively correlated with WUE, accounting for 92.67% of the basin area. (3) The normalized difference vegetation index (NDVI) and leaf area index (LAI) were negatively correlated with WUE, and the proportions of negatively correlated areas to the total area of the basin were similar; both were between 60 and 70%. The growth of vegetation inhibited the increase in WUE in the basin to a certain extent. Regarding Vapor Pressure Deficit (VPD), the proportions of positive and negative correlation areas with WUE were similar, accounting for 49.58% and 50.42%, respectively. (4) The occurrence of drought events and the enhancement in its degree led to a continuous increase in WUE in the basin; for different land cover types, the correlation of the standardized precipitation evapotranspiration index (SPEI) was in the following order from strongest to weakest: grassland > cropland > forest > shrubland. Full article

(This article belongs to the Special Issue Water Use/Footprint for Agricultural Products during Production, Trade and Consumption Processes, Volume II)

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17 pages, 4531 KiB

Open AccessArticle

Using Artificial Neural Networks to Predict Operational Parameters of a Drinking Water Treatment Plant (DWTP)

by Stylianos Gyparakis, Ioannis Trichakis and Evan Diamadopoulos

Water 2024, 16(19), 2863; https://doi.org/10.3390/w16192863 - 9 Oct 2024

Viewed by 664

Abstract

The scope of the present study is the estimation of key operational parameters of a drinking water treatment plant (DWTP), particularly the dosages of treatment chemicals, using artificial neural networks (ANNs) based on measurable in situ data. The case study consists of the [...] Read more.

The scope of the present study is the estimation of key operational parameters of a drinking water treatment plant (DWTP), particularly the dosages of treatment chemicals, using artificial neural networks (ANNs) based on measurable in situ data. The case study consists of the Aposelemis DWTP, where the plant operator had an estimation of the ANN output parameters for the required dosages of water treatment chemicals based on observed water quality and other operational parameters at the time. The estimated DWTP main operational parameters included residual ozone (O₃) and dosages of the chemicals used: anionic polyelectrolyte (ANPE), poly-aluminum chloride hydroxide sulfate (PACl), and chlorine gas (Cl_2(g)). Daily measurable results of water sample analysis and recordings from the DWTP Supervisory Control and Data Acquisition System (SCADA), covering a period of 38 months, were used as input parameters for the artificial neural network (1188 values for each of the 14 measurable parameters). These input parameters included: raw water supply (Q), raw water turbidity (T₁), treated water turbidity (T₂), treated water residual free chlorine (Cl₂), treated water concentration of residual aluminum (Al), filtration bed inlet water turbidity (T₃), daily difference in water height in reservoir (∆H), raw water pH (pH₁), treated water pH (pH₂), and daily consumption of DWTP electricity (El). Output/target parameters were: residual O₃ after ozonation (O₃), anionic polyelectrolyte (ANPE), poly-aluminum chloride hydroxide sulfate (PACl), and chlorine gas supply (Cl_2(g)). A total of 304 different ANN models were tested, based on the best test performance (tperf) indicator. The one with the optimum performance indicator was selected. The scenario finally chosen was the one with 100 neural networks, 100 nodes, 42 hidden nodes, 10 inputs, and 4 outputs. This ANN model achieved excellent simulation results based on the best testing performance indicator, which suggests that ANNs are potentially useful tools for the prediction of a DWTP’s main operational parameters. Further research could explore the prediction of water chemicals used in a DWTP by using ANNs with a smaller number of operational parameters to ensure greater flexibility, without prohibitively reducing the reliability of the prediction model. This could prove useful in cases with a much higher sample size, given the data-demanding nature of ANNs. Full article

(This article belongs to the Special Issue Application of Artificial Intelligence (AI) in Water Quality Monitoring)

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20 pages, 11222 KiB

Open AccessArticle

Capacity Assessment of a Combined Sewer Network under Different Weather Conditions: Using Nature-Based Solutions to Increase Resilience

by Panagiota Galiatsatou, Antigoni Zafeirakou, Iraklis Nikoletos, Argyro Gkatzioura, Maria Kapouniari, Anastasia Katsoulea, Dimitrios Malamataris and Ioannis Kavouras

Water 2024, 16(19), 2862; https://doi.org/10.3390/w16192862 - 9 Oct 2024

Viewed by 612

Abstract

Severe weather conditions and urban intensification are key factors affecting the response of combined sewer systems, especially during storm events. In this regard, the capacity assessment of combined sewer networks under the impact of rainfall storm events of different return periods was the [...] Read more.

Severe weather conditions and urban intensification are key factors affecting the response of combined sewer systems, especially during storm events. In this regard, the capacity assessment of combined sewer networks under the impact of rainfall storm events of different return periods was the focus of this work. The selected case study area was a mixed-use catchment in the city centre of Thessaloniki, Greece. The hydraulic performance of the examined sewer network was assessed using an InfoWorks ICM model. The results indicated that mitigation strategies, such as the application of nature-based solutions (NBSs) or low-impact developments (LIDs) are considered essential for controlling combined sewer overflows. A multicriteria analysis was conducted to select the most appropriate NBSs/LIDs to be located in the study area to enhance the system’s capacity. The results of this multicriteria analysis were used to propose a combined sewer overflow mitigation scenario, based on the installation of green roofs, as the most highly ranked solution in the analysis performed. Incorporating the proposed NBS/LID in the hydrologic-hydraulic model significantly increased the performance of the studied combined sewer network. Full article

(This article belongs to the Section Hydrology)

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18 pages, 2358 KiB

Open AccessArticle

Development on Surrogate Models for Predicting Plume Evolution Features of Groundwater Contamination with Natural Attenuation

by Yajing Wang, Mingyu Wang and Runfeng Liu

Water 2024, 16(19), 2861; https://doi.org/10.3390/w16192861 - 9 Oct 2024

Viewed by 493

Abstract

Predicting the key plume evolution features of groundwater contamination are crucial for assessing uncertainty in contamination control and remediation, while implementing detailed complex numerical models for a large number of scenario simulations is time-consuming and sometimes even impossible. This work develops surrogate models [...] Read more.

Predicting the key plume evolution features of groundwater contamination are crucial for assessing uncertainty in contamination control and remediation, while implementing detailed complex numerical models for a large number of scenario simulations is time-consuming and sometimes even impossible. This work develops surrogate models with an effective and practicable pathway for predicting the key plume evolution features, such as the distance of maximum plume spreading, of groundwater contamination with natural attenuation. The representative various scenarios of the input parameter combinations were effectively generated by the orthogonal experiment method and the corresponding numerical simulations were performed by the reliable Groundwater Modeling System. The PSO-SVM surrogate models were first developed, and the accuracy was gradually enhanced from 0.5 to 0.9 under a multi-objective condition by effectively increasing the sample data size from 54 sets to 78 sets and decreasing the input variables from 25 of all the considered parameters to a smaller number of the key controlling factors. The statistical surrogate models were also constructed with the fitting degree all above 0.85. The achieved findings provide effective generic surrogate models along with a scientific basis and investigation approach reference for the environmental risk management and remediation of groundwater contamination, particularly with limited data. Full article

(This article belongs to the Special Issue Water Resources, Environment, and Ecosystems: Application of New Technology)

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14 pages, 4979 KiB

Open AccessArticle

Numerical Simulation of Gas–Water Two-Phase Flow Patterns in Fracture: Implication for Enhancing Natural Gas Production

by Dejun Liu, Hai Pu, Kangsheng Xue and Hongyang Ni

Water 2024, 16(19), 2860; https://doi.org/10.3390/w16192860 - 9 Oct 2024

Viewed by 512

Abstract

The main objective of this paper is to investigate the evolution of rock fracture slug structures and decongestion strategies for natural gas extraction processes. For this purpose, the level set method was used to simulate the evolution of the slug structure under the [...] Read more.

The main objective of this paper is to investigate the evolution of rock fracture slug structures and decongestion strategies for natural gas extraction processes. For this purpose, the level set method was used to simulate the evolution of the slug structure under the effect of different flow ratios, fracture surface wettability, and fracture tortuosity. The results show that an increase in the water-to-gas flow ratio and fracture tortuosity leads to a significant increase in the proportion of slug structures in the fracture, while an increase in the surface contact angle leads to a decrease in the proportion of slug structures in the fracture. Based on the above slug structure evolution law, a quantitative characterization method for the slug structure of two-phase fluids considering the combined effects of the water–gas flow ratio, average wall contact angle, and flow channel tortuosity was developed. Subsequently, we engage in further discussion on the optimization of the extraction and decongestion process in natural gas extraction. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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14 pages, 4407 KiB

Open AccessArticle

Geochemical Characteristics and Genesis of Brine Chemical Composition in Cambrian Carbonate-Dominated Succession in the Northeastern Region of Chongqing, Southwestern China

by Zhi-lin Zheng, Bin Xie, Chun-mei Wu, Lei Zhou, Ke Zhang, Bin-chen Zhang and Ping-heng Yang

Water 2024, 16(19), 2859; https://doi.org/10.3390/w16192859 - 9 Oct 2024

Viewed by 584

Abstract

Deeply situated brine is abundant in rare metal minerals, possessing significant economic worth. To the authors’ knowledge, brine present within the Cambrian carbonate-dominated succession in the northeastern region of Chongqing, Southwestern China, has not been previously reported. In this investigation, brine samples were [...] Read more.

Deeply situated brine is abundant in rare metal minerals, possessing significant economic worth. To the authors’ knowledge, brine present within the Cambrian carbonate-dominated succession in the northeastern region of Chongqing, Southwestern China, has not been previously reported. In this investigation, brine samples were collected from an abandoned brine well, designated as Tianyi Well, for the purpose of analyzing the hydrochemical characteristics and geochemical evolution of the brine. Halide concentrations, associated ions, and their ionic ratios within the sampled brine were analyzed. The brine originating from the deep Cambrian aquifer was characterized by high salinity levels, with an average TDS value of 242 ± 11 g/L, and was dominated by a Na-Cl facies. The studied brine underwent a moderate degree of seawater evaporation, occurring between the saturation levels of gypsum and halite, accompanied by some halite dissolution. Compared to modern seawater evaporation, the depletion of Mg²⁺, HCO₃⁻, and SO₄²⁻ concentrations, along with the enrichment of Ca²⁺, Li⁺, K⁺, and Sr²⁺, is likely primarily attributed to water–rock interactions. These interactions include dolomitization, combination of halite dissolution, upwelling of lithium- and potassium-bearing groundwater, calcium sulfate precipitation, biological sulfate reduction (BSR), and the common ion effect within the brine system. This research offers valuable insights into the genesis of the brine within the Cambrian carbonate succession and provides theoretical backing for the development of brine resources in the future. Full article

(This article belongs to the Topic Hydrosphere under the Driving of Human Activity and Climate Change: Status, Evolution and Strategies)

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20 pages, 4143 KiB

Open AccessArticle

A Strain-Controlled Finite Strain Model for CRD Consolidation of Saturated Clays Considering Non-Linear Compression and Permeability Relationships

by Weiyu Wang, Lijun Ke and Yaotian Gu

Water 2024, 16(19), 2858; https://doi.org/10.3390/w16192858 - 9 Oct 2024

Viewed by 543

Abstract

Consolidation is the combined phenomenon of the compression and groundwater seepage of clay. Accurate evaluation of the consolidation characteristic is essential for the design, construction, and long-term stability of geotechnical structures. In this study, a strain-controlled non-linear finite strain model for constant rate-of-deformation [...] Read more.

Consolidation is the combined phenomenon of the compression and groundwater seepage of clay. Accurate evaluation of the consolidation characteristic is essential for the design, construction, and long-term stability of geotechnical structures. In this study, a strain-controlled non-linear finite strain model for constant rate-of-deformation (CRD) consolidation was developed for quickly and reliably predicting the consolidation behavior of clay soils. The model can account for any form of non-linear compression and permeability relationships, thus considering variations in the coefficient of consolidation. Being strain-controlled, it overcomes the limitations of stress-controlled models which require complex numerical iteration. The validity and accuracy of this model were verified through rigorous comparisons with both numerical simulations and experimental data. For normally consolidated soils, a non-linear e-lgσ′compression model was used instead of a linear compression model. For overconsolidated soils, the Harris function compression model was determined to be recommended to overcome the discontinuities in total stress and pore pressure caused by the traditional piecewise e-lgσ′ model. It was also found that determining the steady state of consolidation for normally consolidated soils should use the non-linear method, while the linear method is suggested to be adopted for overconsolidated soils. Full article

(This article belongs to the Special Issue Recent Advances in Groundwater Control in Geotechnical Engineering)

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18 pages, 7268 KiB

Open AccessArticle

Comparison of Machine Learning-Based Predictive Models of the Nutrient Loads Delivered from the Mississippi/Atchafalaya River Basin to the Gulf of Mexico

by Yi Zhen, Huan Feng and Shinjae Yoo

Water 2024, 16(19), 2857; https://doi.org/10.3390/w16192857 - 8 Oct 2024

Viewed by 587

Abstract

Predicting nutrient loads is essential to understanding and managing one of the environmental issues faced by the northern Gulf of Mexico hypoxic zone, which poses a severe threat to the Gulf’s healthy ecosystem and economy. The development of hypoxia in the Gulf of [...] Read more.

Predicting nutrient loads is essential to understanding and managing one of the environmental issues faced by the northern Gulf of Mexico hypoxic zone, which poses a severe threat to the Gulf’s healthy ecosystem and economy. The development of hypoxia in the Gulf of Mexico is strongly associated with the eutrophication process initiated by excessive nutrient loads. Due to the complexities in the excessive nutrient loads to the Gulf of Mexico, it is challenging to understand and predict the underlying temporal variation of nutrient loads. The study was aimed at identifying an optimal predictive machine learning model to capture and predict nonlinear behavior of the nutrient loads delivered from the Mississippi/Atchafalaya River Basin (MARB) to the Gulf of Mexico. For this purpose, monthly nutrient loads (N and P) in tons were collected from US Geological Survey (USGS) monitoring station 07373420 from 1980 to 2020. Machine learning models—including autoregressive integrated moving average (ARIMA), gaussian process regression (GPR), single-layer multilayer perceptron (MLP), and a long short-term memory (LSTM) with the single hidden layer—were developed to predict the monthly nutrient loads, and model performances were evaluated by standard assessment metrics—Root Mean Square Error (RMSE) and Correlation Coefficient (R). The residuals of predictive models were examined by the Durbin–Watson statistic. The results showed that MLP and LSTM persistently achieved better accuracy in predicting monthly TN and TP loads compared to GPR and ARIMA. In addition, GPR models achieved slightly better test RMSE score than ARIMA models while their correlation coefficients are much lower than ARIMA models. Moreover, MLP performed slightly better than LSTM in predicting monthly TP loads while LSTM slightly outperformed for TN loads. Furthermore, it was found that the optimizer and number of inputs didn’t show effects on the LSTM performance while they exhibited impacts on MLP outcomes. This study explores the capability of machine learning models to accurately predict nonlinearly fluctuating nutrient loads delivered to the Gulf of Mexico. Further efforts focus on improving the accuracy of forecasting using hybrid models which combine several machine learning models with superior predictive performance for nutrient fluxes throughout the MARB. Full article

(This article belongs to the Section New Sensors, New Technologies and Machine Learning in Water Sciences)

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18 pages, 2954 KiB

Open AccessArticle

Using the Evolution of a River Technology System to Compare Classification-Based and Citation-Based Technology Networks

by Lin Gan, Yongping Wei and Shuanglei Wu

Water 2024, 16(19), 2856; https://doi.org/10.3390/w16192856 - 8 Oct 2024

Cited by 1 | Viewed by 625

Abstract

With the increasing complexity of societal and environmental problems in the Anthropocene, the use of both classification-based approaches, which provide in-depth understanding within disciplinary boundaries, and citation-based approaches, which provide interdisciplinary research, has been encouraged. However, there are limited comparisons of the knowledge [...] Read more.

With the increasing complexity of societal and environmental problems in the Anthropocene, the use of both classification-based approaches, which provide in-depth understanding within disciplinary boundaries, and citation-based approaches, which provide interdisciplinary research, has been encouraged. However, there are limited comparisons of the knowledge networks produced between these two approaches, which compromises our capacity to manage technological development. This paper aims to investigate the similarities and differences of river technology networks produced using classification-based and citation-based approaches. The World Intellectual Property Organization (WIPO) database from 1863 to 2020 was used as the data source. River technology systems contained three interactive subsystems: water demand, water supply, and water management, and the structure was measured using network-based metrics. It was found that river technology systems constructed using the classification-based and the citation-based approaches developed similarly in terms of their temporal, spatial, and compositional features. The structural differences were attributed to the addition of an external system that draws upon interdisciplinary knowledge beyond water resources. Both approaches can be used for guiding technology management, with the classification-based approach being more effective for understanding the content of innovations and the citation-based approach being more effective in gathering information beyond the water resource discipline. Technologies from more diverse disciplines should be encouraged to address increasingly complex water challenges. Full article

(This article belongs to the Section Hydrology)

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12 pages, 2332 KiB

Open AccessArticle

Dechlorination of Hexachlorobenzene by Ni/Fe Bimetallic Nanoparticles and the Influence of Co-Existing Heavy Metal Ions

by Yuanying Huang, Siwen Liu, Qian Wang, Guoxin Huang, Xueqi Zhang and Yang Liu

Water 2024, 16(19), 2855; https://doi.org/10.3390/w16192855 - 8 Oct 2024

Viewed by 463

Abstract

Hexachlorobenzene (HCB) is one of the most persistent environmental pollutants of global concern. Ni/Fe nanoparticles, with their small particle size, large surface area, and high reactivity, are a promising candidate for HCB degradation. In this work, we investigated the kinetics and products of [...] Read more.

Hexachlorobenzene (HCB) is one of the most persistent environmental pollutants of global concern. Ni/Fe nanoparticles, with their small particle size, large surface area, and high reactivity, are a promising candidate for HCB degradation. In this work, we investigated the kinetics and products of the dechlorination of HCB by Ni/Fe nanoparticles and how the presence of heavy metal ions Cd(Ⅱ) and Zn(Ⅱ) influences the reaction. It is found that 400 μg/L HCB can be rapidly removed by 7.5 g/L Ni/Fe nanoparticles and the removal percentage reaches 99% in 48 h. The removal is facilitated by adsorption and sequential dechlorination of HCB, producing PCB, 1,2,3,4-TeCB, and 1,2,3-TCB as the main products, with 1,2,3,5/1,2,4,5-TeCB, 1,2,4-TCB, and 1,2-DCB as the minor products. The addition of heavy metal ions Cd(Ⅱ) and Zn(Ⅱ) does not significantly affect the removal rate of HCB but hinders the adsorption and degradation of the byproducts through competitive adsorption. Additionally, the concentration of both Cd(Ⅱ) and Zn(Ⅱ) decreases rapidly and achieves over 98% removal in 4 h. Our study reveals that Ni/Fe nanoparticles can remove HCB and heavy metals Cd(Ⅱ) and Zn(Ⅱ) concurrently, with the extent of HCB dechlorination reduced compared to that without heavy metal. These findings may inform the application of Ni/Fe nanoparticles in the treatment of water bodies and soil contaminated by both halogenated aromatics and heavy metal. Full article

(This article belongs to the Special Issue Mine and Water)

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98 pages, 28240 KiB

Open AccessArticle

Water and the Origin of Life

by Marc Henry

Water 2024, 16(19), 2854; https://doi.org/10.3390/w16192854 - 8 Oct 2024

Viewed by 5200

Abstract

This article reviews all the major stages in the origins of life, from the emergence of matter in the initial Big Bang to the modern, civilized human being. On an immaterial level, it is proposed and explained how consciousness necessarily takes precedence over [...] Read more.

This article reviews all the major stages in the origins of life, from the emergence of matter in the initial Big Bang to the modern, civilized human being. On an immaterial level, it is proposed and explained how consciousness necessarily takes precedence over matter. Next, we explain how consciousness, with its ability to process information, selected the water molecule to breathe life into the periodic table of elements. We also explain why the notion of entropy allows us to evolve, “Die Entropie der Welt strebt einem Maximum zu” (second principle), and, therefore, takes precedence over the notion of energy, which, on the contrary, encourages us to preserve what we have, “Die Energie der Welt bleibt konstant” (first principle). This is followed by a discussion of the importance of quantum coherence and the need to rely on a second quantization formalism for a proper understanding of the physical–biochemical properties of water. Moreover, throughout the argument developed on the best and most fundamental things science has to offer, care is taken to link this knowledge to the great philosophies of the West (Greece), the East (China and India), and even to practices of a shamanic nature (Africa and America). Hence, finally, we propose reconsidering all musical practice within the framework of the diapason of water at a frequency of 429.62 Hz, as well as all therapeutic practice on the basis of seven clearly identified and established frameworks of thought. Full article

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14 pages, 4019 KiB

Open AccessArticle

Steady-State Shape Factor for a Slug Test in an Unconfined Aquifer

by Florimond De Smedt

Water 2024, 16(19), 2853; https://doi.org/10.3390/w16192853 - 8 Oct 2024

Viewed by 432

Abstract

A new solution is presented for the steady-state shape factor of a partially penetrating well in an unconfined aquifer. The problem is solved by taking into account mixed boundary conditions at the well, i.e., zero flux at the well casing and constant head [...] Read more.

A new solution is presented for the steady-state shape factor of a partially penetrating well in an unconfined aquifer. The problem is solved by taking into account mixed boundary conditions at the well, i.e., zero flux at the well casing and constant head at the well screen equal to the head in the well so that the flow through the well screen is non-uniform. The new method is compared with established methods, such as those of Bouwer and Rice and Zlotnik et al., demonstrating that the new approach provides more accurate results under certain conditions. The comparison highlights that the new method is particularly effective in scenarios where the assumptions of uniform flow through the well screen do not hold. This study assumes idealized conditions, such as homogeneity, isotropy, and negligible storativity in the aquifer, which may limit the method’s applicability in more complex environments. The computational demands of the iterative solution process may pose challenges for practical use, especially in resource-constrained settings. Full article

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23 pages, 7766 KiB

Open AccessArticle

Hydrochemical Characteristics and Formation Mechanism of Geothermal Fluids in Zuogong County, Southeastern Tibet

by Sihang Han, Dawa Nan, Zhao Liu, Nima Gesang, Chengcuo Bianma, Haihua Zhao, Yadong Zheng and Peng Xiao

Water 2024, 16(19), 2852; https://doi.org/10.3390/w16192852 - 8 Oct 2024

Viewed by 511

Abstract

Zuogong County is located in the southeast of Tibet, which is rich in hot spring geothermal resources, but its development and utilization degree are low, and the genetic mechanism of the geothermal system is not clear. Hydrogeochemical characteristics of geothermal water are of [...] Read more.

Zuogong County is located in the southeast of Tibet, which is rich in hot spring geothermal resources, but its development and utilization degree are low, and the genetic mechanism of the geothermal system is not clear. Hydrogeochemical characteristics of geothermal water are of great significance in elucidating the genesis and evolution of geothermal systems, as well as the sustainable development and utilization of geothermal resources. The hydrogeochemical characteristics and genesis of the geothermal water in Zuogong County were investigated using hydrogeochemical analysis, a stable isotope (δD, δ¹⁸O) approach, and an inverse simulation model for water–rock reactions using the PHREEQC. The results indicated that the Zuogong geothermal system is a deep circulation heating type without a magmatic heat source. The chemical types present in the geothermal water from the Zuogong area are HCO₃ and HCO₃·SO₄, and the main cations are Na⁺ and Ca²⁺. The groundwater is replenished by atmospheric precipitation and glacier meltwater. The salt content of geothermal water mainly comes from the interaction between water and surrounding rocks during the deep circulation process. The reservoir temperature of geothermal water in Zuogong is 120–176 °C before mixing with non-geothermal water and drops to 62–98 °C after mixing with 58 to 79% of non-geothermal water. According to the proposed conceptual model, geothermal water mainly produces water–rock interaction with aluminosilicate minerals in the deep formation, while in shallow areas it interacts mainly with sulfate minerals. These findings contribute to a better understanding of the geothermal system in Zuogong County, Tibet. Full article

(This article belongs to the Section Hydrogeology)

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23 pages, 3173 KiB

Open AccessArticle

Use of an Ecological Compensation Model in Water Resource Development: A Case Study from Shaanxi Province, China

by Longxing Chen, Ping Han and Gaopan Zhang

Water 2024, 16(19), 2851; https://doi.org/10.3390/w16192851 - 8 Oct 2024

Viewed by 481

Abstract

This study aims to analyze the current situation of water resource management in Shaanxi Province, study the basic principles of ecological compensation, evaluate the impact of water conservation projects on the ecological environment by establishing a model, and propose a sustainable water resource [...] Read more.

This study aims to analyze the current situation of water resource management in Shaanxi Province, study the basic principles of ecological compensation, evaluate the impact of water conservation projects on the ecological environment by establishing a model, and propose a sustainable water resource management model. Hanzhong City has certain typicality and representativeness within Shaanxi Province, and the problems it faces in water resource management and ecological environment may represent the entire province or similar regions. At the same time, Hanzhong City has rich data and research foundations. Therefore, by conducting a detailed analysis of the current water resource status in the Hanzhong City area of Shaanxi Province, the problems in current water resource management are revealed, and the basic principles of ecological compensation are intensely studied. The original ecological compensation plan in Shaanxi Province has been summarized. Guided by the concept of sustainable development, an ecological compensation model is established using algorithms, and the model is applied to sustainable water resource management. Establish a model for water conservation and water resource management through data collection, preprocessing, and cleaning, and apply it to practical cases in Hanzhong City. Through simulation and analysis of Hanzhong City, the new water resource management model effectively mitigates the adverse effects of water conservation projects on the ecological environment while improving water resource utilization efficiency. The changes in various environmental parameters indicate that the new plan has improved the ecological environment. Through the application of the model, the ecological compensation plan formulated has achieved sustainable protection of the ecological environment while promoting economic development. This study proposes a sustainable water resource management model through a comprehensive study of water resource management and ecological compensation in Shaanxi Province and verifies it in practical cases, demonstrating that the model has not only good applicability but also has significant effects in promoting economic growth and ecological environment protection. Full article

(This article belongs to the Special Issue Effects of Groundwater and Surface Water on the Natural Geo-Hazards, 2nd Edition)

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24 pages, 8111 KiB

Open AccessReview

Research Hotspots in and Progress of Stable Isotopic Techniques Applied in Tracing Mine Water Pollution and Its Environmental Impact: A Bibliometric and Visualization Analysis from 1998 to 2023

by Kai Zhang, Xiangyu Chen, Menghua Chen, Xuying Tan and Kaisheng Jiang

Water 2024, 16(19), 2850; https://doi.org/10.3390/w16192850 - 8 Oct 2024

Viewed by 1113

Abstract

Stable isotope techniques have become a critical tool for tracking mine water and identifying its contamination. In order to explore in depth the research hotspots and trends in stable isotope technology in the study of mine water and the environmental pollution it induces, [...] Read more.

Stable isotope techniques have become a critical tool for tracking mine water and identifying its contamination. In order to explore in depth the research hotspots and trends in stable isotope technology in the study of mine water and the environmental pollution it induces, the Web of Science Core Collection (WoSCC) database of the relevant literature in this field from 1998 to 2023 was used for visual bibliometric analysis by applying CiteSpace software (version 5.7R5). The results showed that the periodical literature in this field shows a fluctuating upward trend. In the cooperation network of country and institution, the centrality of the United States was as high as 0.74 and 0.23, much higher than that of other countries, which means that in terms of the institutions, the number of publications, and the status of research, the United States is ahead of other countries. China’s research started later than the United States’s but is developing rapidly. Although its importance and influence in this research field are only slightly lower than those of the United States, China still needs to improve its cooperation with other countries and regions. The research hotspots in this area center around identifying and understanding pollution processes, studying mine water sources and mixing, exploring the evolution of water chemistry and its isotopic composition, and investigating the environmental impacts of mine water. Innovative isotope-tracing methods and techniques, isotope fractionation mechanisms, sources of sulfate, and their impact on the water environment will remain the focus of the forthcoming research phase. This study uses bibliometrics to systematically summarize the research hotspots and trends in stable isotope techniques in mine water problems in terms of their footprint in the academic literature, which is of great significance for the utilization of water resources in mine drainage and pollution control in mines. Full article

(This article belongs to the Section Water Quality and Contamination)

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14 pages, 2497 KiB

Open AccessArticle

Pilot Study on the Possibility of Improving Water Treatment Sludge Management in Almaty

by Kairat Ospanov, Erzhan Kuldeyev, Dariusz Andraka and Manat Alzhigitova

Water 2024, 16(19), 2849; https://doi.org/10.3390/w16192849 - 8 Oct 2024

Viewed by 915

Abstract

This article presents the results of a pilot study on the treatment of sludge from a water treatment plant in the city of Almaty, Republic of Kazakhstan, to ensure further disposal. The main objective of the study was to compare the efficiency of [...] Read more.

This article presents the results of a pilot study on the treatment of sludge from a water treatment plant in the city of Almaty, Republic of Kazakhstan, to ensure further disposal. The main objective of the study was to compare the efficiency of sludge drying by natural and artificial methods. The qualitative characteristics of the leachate from the dewatering unit, the chemical composition of the dried sludge and the granulometric analysis of the dried sludge were also studied. The greatest reduction in moisture content was recorded for drying in natural conditions (2.1%), but this process required the longest drying time. The leachate obtained from sludge dewatering was characterized by significant contamination (e.g., turbidity—55.65 on average, color—67.7, total Fe—5.15 mg/L, total N—79.6 mg/L, COD—311 mg/L, BOD—336.15 mg/L), which indicates the need for its pretreatment before further management in the technological system of the treatment station. The content of chemical substances contained in the dry residue of the sludge was also determined, of which aluminum was 0.94–13.8 mg/kg, silicon was 50.24–146.3 mg/kg, potassium was 1.72–5.51. mg/kg, calcium was 71.8–79.1 mg/kg, iron was 2.0–7.54 mg/kg and nickel was 0.9–4.4 mg/kg. A particle size analysis of the dried sludge showed that the majority fractions were fine and very fine sand, with a total of 20.2%, and silt and clay, with a total of 78.3%. Such properties justify the rationality of considering the reuse of dried sludge as a raw material for making, for example, construction materials or soil remediation material. Full article

(This article belongs to the Section Wastewater Treatment and Reuse)

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22 pages, 8540 KiB

Open AccessArticle

Morphological Characteristics of Constrained Meandering Rivers in the Loess Plateau

by Bin Li, Yanjie Liang, Xiaolian Yan, Shuqing Yang, Xin Li and Jun Lu

Water 2024, 16(19), 2848; https://doi.org/10.3390/w16192848 - 8 Oct 2024

Viewed by 608

Abstract

In the Loess Plateau of China, loess is widely distributed and forms a unique geomorphic feature of the world. Meanwhile, the Yellow River water and sediment regulation system is under construction. Nonetheless, the morphological characteristics of constrained meandering rivers in the Loess Plateau [...] Read more.

In the Loess Plateau of China, loess is widely distributed and forms a unique geomorphic feature of the world. Meanwhile, the Yellow River water and sediment regulation system is under construction. Nonetheless, the morphological characteristics of constrained meandering rivers in the Loess Plateau are still unknown due to the difficulty of extracting the sediment-laden water body. An improved method is proposed based on Landsat 8 imagery, which automatically extracts the multi-band spectral relationship of high-sediment-concentration rivers in valleys. This study analyzes the morphological characteristics of constrained meandering rivers in the middle reaches of the Yellow River Basin, including their sinuosity, periodicity, curvature, and skewness based on the deflection points bend segmentation and continuous wavelet transform methods. These characteristics are then compared with those of other constrained meandering rivers and alluvial meandering rivers. The results show that the sinuosity of the constrained river bends is generally low (with an average of 1.55) due to limitations imposed by the riverbanks, which prevent full development. The average dimensionless curvature radius of the constrained rivers is 18.72, lower than that of alluvial rivers. The skewing angle of the constrained river bends typically inclines upstream, with a proportion reaching 59.44%. In constrained river bends, as the sinuosity increases, the proportion of bends skewing upstream initially increases and then gradually decreases. This indicates that constrained river bends can develop similarly to alluvial bends at lower sinuosity but are limited by the mountains on both sides at medium sinuosity. The analysis of river characteristics in regions with different geological structures reveals the effect of geological structures on the formation of constrained rivers in the Loess Plateau. These findings can provide a reference for selecting reservoir dam sites and are important for the dredging engineering layout in the middle reaches of the Loess Plateau. They also offer quantitative explanations for the meandering characteristics of these rivers. Full article

(This article belongs to the Section Hydrogeology)

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16 pages, 12239 KiB

Open AccessArticle

Biodiversity and Soil Reinforcement Effect of Vegetation Buffer Zones: A Case Study of the Tongnan Section of the Fujiang River Basin

by Xinhao Wang, Dongsheng Liu, Zhihui Chang, Jiang Tang, Yunqi Wang, Yanlei Wang, Sheng Huang, Tong Li, Zihan Qi and Yue Hu

Water 2024, 16(19), 2847; https://doi.org/10.3390/w16192847 - 7 Oct 2024

Viewed by 581

Abstract

The riparian vegetation buffer zone is an important component of riverbank ecosystems, playing a crucial role in soil consolidation and slope protection. In this study, the riparian vegetation buffer zones in the Tongnan section of the Fujiang River Basin were selected as the [...] Read more.

The riparian vegetation buffer zone is an important component of riverbank ecosystems, playing a crucial role in soil consolidation and slope protection. In this study, the riparian vegetation buffer zones in the Tongnan section of the Fujiang River Basin were selected as the research object. Surveys and experiments were conducted to assess the species composition and the soil and water conservation effectiveness of the riparian vegetation buffer zone. There are a total of 35 species, mainly comprising angiosperms and ferns. The dominant species include Cynodon dactylon, Setaria viridis, Phragmites australis, Erigeron canadensis, and Melilotus officinalis. The Patrick richness index (R) and Shannon–Wiener diversity index (H) are more significantly influenced by the types of land use in the surrounding area, whereas the impact on the Simpson diversity index (D) and Pielou uniformity index (E) is comparatively less pronounced. When the root diameter is less than 0.2 mm, the tensile strength of Cynodon dactylon roots is the highest. For root diameters larger than 0.2 mm, Melilotus officinalis roots exhibit the highest tensile strength. The presence of plant root systems significantly reduces erosion, delaying the time to reach maximum erosion depth by 1–4 min, decreasing erosion depth by 9–38 mm, and reducing the total amount of erosion by 20.17–58.90%. The anti-scouribility effect of Cynodon dactylon is significantly better than that of Setaria viridis. The root system notably enhances soil shear strength, delaying the shear peak by 0.26–4.8 cm, increasing the shear peak by 4.76–11.37 kPa, and raising energy consumption by 23.76–46.11%. Phragmites australis has the best resistance to shear, followed by Erigeron canadensis, with Melilotus officinalis being the least resistant. Therefore, to balance the anti-scouribility effect and shear resistance of plant roots, it is recommended to use a combination of Cynodon dactylon and Phragmites australis for shallow-rooted and deep-rooted planting. This approach enhances the water and soil conservation capacity of riverbanks. Full article

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16 pages, 4169 KiB

Open AccessArticle

Massive Outbreak of Aurelia coerulea in Geoje Bay, Korea

by Kyoung Yeon Kim, Seok Hyun Youn, Seo Yeol Choi and Wongyu Park

Water 2024, 16(19), 2846; https://doi.org/10.3390/w16192846 - 7 Oct 2024

Viewed by 475

Abstract

This study was carried out to elucidate the causes of massive outbreaks of Aurelia coerulea in Geoje Bay, Korea, from November 2022 to October 2023. Adult medusae consistently spawn with planulae, and the populations of A. coerulea in Geoje Bay could be [...] Read more.

This study was carried out to elucidate the causes of massive outbreaks of Aurelia coerulea in Geoje Bay, Korea, from November 2022 to October 2023. Adult medusae consistently spawn with planulae, and the populations of A. coerulea in Geoje Bay could be categorized into current-year and overwintering populations. The current-year population began with the emergence of ephyrae in February and grew until October, while the overwintering population comprised a mixture of surviving current-year population and additional individuals that joined during the warm season. The size of the planulae are significantly larger than the annual average during the cold season. These results appear to be the energy accumulation of planulae for polyp formation under low water temperatures. Planulae form polyps within a temperature range of 5–25 °C, suggesting the possibility of year-round polyp recruitment. In Geoje Bay, the highest appearance rate of A. coerulea was in April (8.71 ± 12.5 ind. m⁻³), with ephyrae experiencing higher growth rates up to the young medusa stage. However, from April, a decline in zooplankton biomass resulted in reduced growth rates in adults, indicating that jellyfish growth was primarily regulated by food availability. Additionally, submersed oyster shells in oyster farms served as the main habitat for jellyfish polyps. A. coerulea populations were also characterized by the continuous spawning of planulae throughout the year. In conclusion, this study suggests that stable polyp habitats, abundant food supply during the initial developmental period of the population, and suitable ranges of water temperature were significant factors inducing the massive outbreak of A. coerulea in Geoje Bay, Korea. Full article

(This article belongs to the Special Issue Aquatic Environmental Pollution and Ecotoxicological Studies)

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28 pages, 9980 KiB

Open AccessArticle

Research on the Influence of Particles and Blade Tip Clearance on the Wear Characteristics of a Submersible Sewage Pump

by Guangjie Peng, Jinhua Yang, Lie Ma, Zengqiang Wang, Hao Chang, Shiming Hong, Guangchao Ji and Yuan Lou

Water 2024, 16(19), 2845; https://doi.org/10.3390/w16192845 - 7 Oct 2024

Viewed by 565

Abstract

A submersible sewage pump is designed for conveying solid–liquid two-phase media containing sewage, waste, and fiber components, through its small and compact design and its excellent anti-winding and anti-clogging capabilities. In this paper, the computational fluid dynamics–discrete element method (CFD-DEM) coupling model is [...] Read more.

A submersible sewage pump is designed for conveying solid–liquid two-phase media containing sewage, waste, and fiber components, through its small and compact design and its excellent anti-winding and anti-clogging capabilities. In this paper, the computational fluid dynamics–discrete element method (CFD-DEM) coupling model is used to study the influence of different conveying conditions and particle parameters on the wear of the flow components in a submersible sewage pump. At the same time, the energy balance equation is used to explore the influence mechanism of different tip clearance sizes on the internal flow pattern, wear, and energy conversion mechanism of the pump. This study demonstrates that increasing the particle volume fraction decreases the inlet particle velocity and intensifies wear in critical areas. When enlarging the tip clearance thickness from 0.4 mm to 1.0 mm, the leakage vortex formation at the inlet is enhanced, leading to increased wear rates in terms of the blade and volute. Consequently, the total energy loss and turbulent kinetic energy generation increased by 3.57% and 2.25%, respectively, while the local loss coefficient in regard to the impeller channel cross-section increased significantly. The findings in this study offer essential knowledge for enhancing the performance and ensuring the stable operation of pumps under solid–liquid two-phase flow conditions. Full article

(This article belongs to the Special Issue Hydrodynamic Science Experiments and Simulations)

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21 pages, 5459 KiB

Open AccessArticle

A Practical, Adaptive, and Scalable Real-Time Control Approach for Stormwater Storage Systems

by Ruijie Liang, Holger Robert Maier, Mark Andrew Thyer and Graeme Clyde Dandy

Water 2024, 16(19), 2844; https://doi.org/10.3390/w16192844 - 7 Oct 2024

Viewed by 1425

Abstract

Traditionally, urban stormwater infrastructure systems consist of passive infrastructure that is not actively controlled in response to rainfall events. Recently, real-time control (RTC) has been considered as a means to significantly increase the capacity and lifespan of these systems. This paper introduces the [...] Read more.

Traditionally, urban stormwater infrastructure systems consist of passive infrastructure that is not actively controlled in response to rainfall events. Recently, real-time control (RTC) has been considered as a means to significantly increase the capacity and lifespan of these systems. This paper introduces the target flow control systems (TFCS) approach, which can use real-time control of systems of storages to achieve the desired flow conditions at the locations of interest. The first distinctive feature of this approach is that it does not require calibration to catchment-specific data, unlike existing approaches. This means that the TFCS approach is generally applicable to different catchments and is able to respond to future changes in runoff due to land use and/or climate change. The second distinctive feature is that the approach only requires storage-level information measured in real time with the aid of low-cost pressure sensors. This means that the approach is practical and relatively easy to implement. In addition to the introduction of the novel TFCS approach, a key innovation of this study is that the approach is tested on three case studies, each with different physical configurations and stormwater management objectives. Another key innovation is that the TFCS approach is compared to five RTC approaches, including three of the best-performing advanced approaches from the literature. Comparisons of multiple RTC approaches that consider both performance and practicality across multiple case studies are rare. Results show that the TFCS approach is the only one of the five control approaches analysed that has both the best overall performance and the highest level of practicality. The outcomes highlight the potential of the TFCS approach as a practical RTC approach that is applicable to a wide range of catchments with different stormwater management objectives. By maximizing the performance of existing stormwater storages, the TFCS approach can potentially extend the lifespan of existing infrastructure and avoid costly upgrades due to increased runoff caused by land use and climate change. Full article

(This article belongs to the Special Issue Urban Stormwater Control, Utilization, and Treatment)

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16 pages, 2690 KiB

Open AccessArticle

Performance Evaluation of a Pilot-Scale Constructed Wetland with Typha latifolia for Remediation of Domestic Wastewater in Zimbabwe

by Richwell Alufasi, Wilson Parawira, Cuthbert J. Zvidzai, Alexandros I. Stefanakis, Nancy Musili, Phiyani Lebea, Ereck Chakauya and Walter Chingwaru

Water 2024, 16(19), 2843; https://doi.org/10.3390/w16192843 - 7 Oct 2024

Viewed by 1039

Abstract

The management of wastewater remains a challenge, particularly in developing countries. The potential use of constructed wetlands to treat wastewater is promising but their contaminant removal efficiencies, particularly in a tropical country such as Zimbabwe, are not fully understood. A pilot-scale study was [...] Read more.

The management of wastewater remains a challenge, particularly in developing countries. The potential use of constructed wetlands to treat wastewater is promising but their contaminant removal efficiencies, particularly in a tropical country such as Zimbabwe, are not fully understood. A pilot-scale study was undertaken in Zimbabwe to evaluate the efficiency of vertical-flow constructed wetlands planted with Typha latifolia in the treatment of domestic wastewater. Four pilot subsurface vertical-flow constructed wetland units (measuring 1 m × 1 m × 1.1 m) were built from concrete. The units were filled with waste rock from a nickel mine. Three units were planted with Typha latifolia while the fourth one was left unplanted, acting as the control. Each unit was loaded with wastewater at a rate of 220 dm³/day. Physico-chemical and bacteriological parameters were analyzed during the winter season. Physico-chemical and bacterial contaminant concentrations were significantly lower in the effluent than in the influent, and the system achieved maximum removals for BOD₅, COD, TDS, TSS, nitrates, phosphates, phosphate pentoxide, phosphorus, and E. coli of 56.01%, 82.87%, 30.61%, 90.40% 17.26%, 35.80%, 36.19%, 40.64%, and 90.28%, respectively. The study shows that constructed wetland systems can be successfully established for the removal of physical, chemical, and microbial contaminants from domestic wastewater. Full article

(This article belongs to the Special Issue Water Quality, Wastewater Treatment and Water Recycling)

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26 pages, 5284 KiB

Open AccessReview

Water Management as a Social Field: A Method for Engineering Solutions

by Miguel A. De Luque-Villa and Mauricio González-Méndez

Water 2024, 16(19), 2842; https://doi.org/10.3390/w16192842 - 7 Oct 2024

Viewed by 628

Abstract

This paper proposes the use of Pierre Bourdieu’s sociological concepts of social fields, capital, and habitus to analyze water management in Colombia. By mapping the social dynamics of water management, this study examines the interactions and power relationships among agents, including government agencies, [...] Read more.

This paper proposes the use of Pierre Bourdieu’s sociological concepts of social fields, capital, and habitus to analyze water management in Colombia. By mapping the social dynamics of water management, this study examines the interactions and power relationships among agents, including government agencies, private companies, academic institutions, non-profits, and local communities. The analysis reveals how various forms of capital, such as economic, cultural, social, and symbolic, influence water management practices, policies, and the distribution of power. Integrating agent-based modeling with hydrological simulations provides a more nuanced understanding of how social dynamics influence water management. This interdisciplinary approach helps develop more adaptive and equitable strategies by capturing the complex interactions between human behavior and environmental factors. This study highlights the need to localize the analysis of the social field to capture regional customs and specific social dynamics. This localized approach ensures that water management strategies are more relevant, context sensitive, and sustainable. This paper advocates for the wider adoption of agent-based modeling in water management, proposing a methodology that combines the engineering principles of practical problem solving and adaptive design with an understanding of the social complexities in water management. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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20 pages, 435 KiB

Open AccessArticle

Financial Mechanism for Sustainable Development of the Marine Economy with Respect to Technology, Digitalization, and Low Carbonization

by Sui Sun, Zhe Zhang and Mi Tan

Water 2024, 16(19), 2841; https://doi.org/10.3390/w16192841 - 7 Oct 2024

Viewed by 482

Abstract

This study explores the impact of regional financial development on the sustainable growth of the marine economy across 14 coastal cities in Guangdong Province from 2004 to 2022. To assess this, a comprehensive index system was developed to measure marine economic sustainability, incorporating [...] Read more.

This study explores the impact of regional financial development on the sustainable growth of the marine economy across 14 coastal cities in Guangdong Province from 2004 to 2022. To assess this, a comprehensive index system was developed to measure marine economic sustainability, incorporating key factors such as capital investment, production efficiency, and processing and trade. The findings indicate that financial development significantly enhances the sustainable growth of the marine economy. However, the interaction between financial development, technology digitalization, and low-carbon initiatives leads to diminishing returns in terms of sustainability. Through the use of the Moran index and the spatial Durbin model, the analysis reveals a dual outcome: while financial development positively influences a city’s marine economic sustainability, it exerts negative spillover effects on neighboring cities. Previous studies have primarily focused on the relationship between financial development and the marine economy at the national or provincial level, leaving a gap in understanding these dynamics at the city level. Furthermore, the coordination between financial development and marine economic sustainability across cities within the same region remains largely unexplored. This study addresses these gaps by investigating city-level dynamics and examining intercity coordination between financial development and marine economic growth. The results offer a novel perspective for policymakers, highlighting strategies to balance regional financing for the marine economy with targeted investments in science, technology, digitalization, and low-carbon initiatives. This approach seeks to optimize resource allocation and mitigate potential substitution effects. Ultimately, this research contributes to a more nuanced understanding of the complex interplay between financial development and the marine economy at both city and regional levels. Full article

(This article belongs to the Special Issue Marine Bearing Capacity and Economic Growth)

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