Water

13 pages, 5756 KiB

Open AccessTechnical Note

Machine Learning Based Peach Leaf Temperature Prediction Model for Measuring Water Stress

by Heetae Kim, Minyoung Kim, Youngjin Kim, Byounggap Kim, Choungkeun Lee and Jaeseung No

Water 2024, 16(21), 3157; https://doi.org/10.3390/w16213157 - 4 Nov 2024

Viewed by 629

When utilizing the Crop Water Stress Index (CWSI), the most critical factor is accurately measuring canopy temperature, which is typically done using infrared sensors and imaging cameras. In this study, however, we aimed to develop a machine learning model capable of predicting leaf [...] Read more.

When utilizing the Crop Water Stress Index (CWSI), the most critical factor is accurately measuring canopy temperature, which is typically done using infrared sensors and imaging cameras. In this study, however, we aimed to develop a machine learning model capable of predicting leaf temperature based on environmental data, without relying on sensors, for calculating CWSI. The data underwent preprocessing to remove outliers and missing values. The number of training data points for each factor was 307,924. After data preprocessing, a Pearson correlation analysis (bivariate correlation coefficient) was conducted to select the training data for model operation. The relationship between leaf temperature and air temperature showed a strong positive correlation of 0.928 (p < 0.01). Solar radiation and relative humidity were also found to have high correlations. However, wind speed and soil moisture tension showed very low correlations with leaf temperature and were excluded from the model operation. The Decision Tree, Random Forest, and Gradient Boosting models were selected, and each model was evaluated using RMSE (Root Mean Squared Error), MAE (Mean Absolute Error), MSE (Mean Squared Error), and R² (coefficient of determination). The evaluation results showed that the Gradient Boosting model had a high R² (0.97) and low RMSE (0.88) and MAE (0.54), making it the most suitable model for predicting leaf temperature. Through the leaf temperature prediction model developed in this study, labor and costs associated with sensors can be reduced, and by applying it to real agricultural settings, it can improve crop quality and enhance the sustainability of agriculture. Full article

(This article belongs to the Special Issue Evapotranspiration and Plant Water Stress Measurements as the Driving Standard for Agricultural Irrigation)

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14 pages, 4975 KiB

Open AccessArticle

Prediction of Sediment Transport and Deposition in the Stone Buddha Temple Reservoir Based on HD and ST Bidirectional Coupling Model

by Xiang-Xiang Li, Zhen-Wei Gao, Peng-Fei Zhang and Bin Yan

Water 2024, 16(21), 3156; https://doi.org/10.3390/w16213156 - 4 Nov 2024

Viewed by 505

Abstract

Reservoirs deliver vital ecological services, including water storage and drainage. However, these functions are increasingly compromised by the dual pressures of climate change and human activities. Among the most pressing concerns is reservoir sedimentation, highlighting the urgency of investigating hydrodynamic sediment scouring. This [...] Read more.

Reservoirs deliver vital ecological services, including water storage and drainage. However, these functions are increasingly compromised by the dual pressures of climate change and human activities. Among the most pressing concerns is reservoir sedimentation, highlighting the urgency of investigating hydrodynamic sediment scouring. This study focuses on the plain reservoirs of Liaoning Province, using the Shifo Temple Reservoir as a case study. An optimized sediment scouring scheme was developed based on the reservoir’s hydrodynamic characteristics to improve water and sediment management. A coupled hydrodynamic and sediment transport (ST) model was constructed to simulate runoff dynamics and sediment distribution within the Liao he River Basin, while the MIKE21 model was applied to simulate the interaction between the hydrodynamics and sediment transport. The study analyzed groundwater dynamics across different runoff scenarios, seasons, and representative years, offering a scientific foundation for optimizing water and sediment allocation strategies. The results demonstrated a strong correlation between simulated and observed data during validation, confirming the accuracy of the hydrodynamic simulations. Utilizing the coupled HD and ST modules, the study proposed a sediment transfer scheme. The analysis revealed that flow rates between 165 and 190 m³/s significantly enhance sediment scouring in the long term (2029–2039) compared to the short term (2024–2029), effectively reducing sedimentation, minimizing deposition length, and lowering silt removal costs. The findings offer critical insights for predicting reservoir evolution and conducting risk assessments, thereby contributing to the sustainable management and ecological restoration of water systems in Liaoning Province. Full article

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19 pages, 5784 KiB

Open AccessArticle

Benthic Microbes on the Shore of Southern Lake Taihu Exhibit Ecological Significance and Toxin-Producing Potential Through Comparison with Planktonic Microbes

by Qihang Zhao, Bin Wu, Jun Zuo, Peng Xiao, He Zhang, Yaping Dong, Shuai Shang, Guanning Ji, Ruozhen Geng and Renhui Li

Water 2024, 16(21), 3155; https://doi.org/10.3390/w16213155 - 4 Nov 2024

Viewed by 557

Abstract

Water quality and aquatic ecosystems along lakeshores are vital for ecological balance and human well-being. However, research has primarily focused on plankton, with benthic niches being largely overlooked. To enhance understanding of benthic microbial communities, we utilized 16S and 18S rRNA sequencing alongside [...] Read more.

Water quality and aquatic ecosystems along lakeshores are vital for ecological balance and human well-being. However, research has primarily focused on plankton, with benthic niches being largely overlooked. To enhance understanding of benthic microbial communities, we utilized 16S and 18S rRNA sequencing alongside multivariate statistical methods to analyze samples from the shoreline of Lake Taihu in Huzhou City, Zhejiang Province. Our results reveal a marked difference in species composition between benthic and planktonic microorganisms, with benthic cyanobacteria predominantly comprising filamentous genera like Tychonema, while 95% of planktonic cyanobacteria were Cyanobium. The β-diversity of benthic microorganisms was notably higher than that of planktonic counterparts. The neutral community model indicated that stochastic processes dominated planktonic microbial assembly, while deterministic processes prevailed in benthic communities. Null models showed that homogeneous selection influenced benthic community assembly, whereas planktonic communities were affected by undominated processes and dispersal limitation. Network analysis indicated that planktonic networks were more stable than benthic networks. Importantly, dominant benthic cyanobacterial genera posed potential toxin risks, highlighting the need for enhanced monitoring and ecological risk assessment. Overall, these findings enhance our understanding of benthic and planktonic microbial communities in lakeshores and offer valuable insights for aquatic assessment and management in eutrophicated environments. Full article

(This article belongs to the Special Issue Technological and Mechanism Research on Algal Bloom Mitigation and Resource Recycling)

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18 pages, 14676 KiB

Open AccessArticle

Study on the Fine Characterization of Spatial Distribution and Predictive Modeling of Remediation of Site Pollution

by Jun Yang and Caijie Wei

Water 2024, 16(21), 3154; https://doi.org/10.3390/w16213154 - 4 Nov 2024

Viewed by 498

Abstract

The present study focuses on a site contaminated with halogenated hydrocarbons, utilizing a detailed inventory of contamination data to achieve the precise characterization of groundwater pollution. Employing MOFLOW-2000 software, a groundwater flow model was established for the study area. In conjunction with MT3DMS, [...] Read more.

The present study focuses on a site contaminated with halogenated hydrocarbons, utilizing a detailed inventory of contamination data to achieve the precise characterization of groundwater pollution. Employing MOFLOW-2000 software, a groundwater flow model was established for the study area. In conjunction with MT3DMS, a predictive model was constructed to simulate and forecast the spatiotemporal distribution of contaminant migration and attenuation following site remediation. The simulation area was delineated based on geographical features, with the vertical simulation range of strata also determined. To establish a hydrogeological conceptual model for the target remediation site, comprehensive hydrogeological data were collected, encompassing geological structures, hydrological parameters, and rainfall information. Model calibration was based on the six layers of low-permeability aquifer intervals revealed by geological exploration wells MW1–5, as well as the distribution of groundwater-level contours and rainfall data. Based on data from September 2010, an initial three-dimensional model of tetrachloroethylene (PCE) distribution was generated. Subsequently, a solute transport model for PCE was established, incorporating various enhanced reductive dechlorination (ERD) remediation strategies applied at different times and locations. Calibration against actual monitoring data revealed the presence of unmonitored dense non-aqueous phase liquids (DNAPLs) at the site, contributing to the continuous release and elevation of PCE concentrations. By accounting for DNAPL release, the calibrated transport and attenuation model closely matched observed concentration decay patterns, effectively capturing the actual dynamics of contaminant transport and attenuation within the groundwater system. The modeling approach proposed in this study provides important support for contamination remediation and attenuation at the current site, and it is also applicable to simulating and predicting pollution scenarios at similar sites. Full article

(This article belongs to the Topic Organic Pollution in Soil and Groundwater)

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17 pages, 6991 KiB

Open AccessArticle

Multi-Step Ahead Water Level Forecasting Using Deep Neural Networks

by Fahimeh Sharafkhani, Steven Corns and Robert Holmes

Water 2024, 16(21), 3153; https://doi.org/10.3390/w16213153 - 4 Nov 2024

Viewed by 567

Abstract

Stream gauge height (water level) is a significant indicator for forecasting future floods. Flooding occurs when the water level exceeds the flood stage. Predicting imminent floods can save lives, protect infrastructure, and improve road traffic management and transportation. Deep neural networks have been [...] Read more.

Stream gauge height (water level) is a significant indicator for forecasting future floods. Flooding occurs when the water level exceeds the flood stage. Predicting imminent floods can save lives, protect infrastructure, and improve road traffic management and transportation. Deep neural networks have been increasingly used in this domain due to their predictive capabilities in capturing complex features and interdependencies. This study employs four distinct models—Multi-Layer Perceptron (MLP), Long Short-Term Memory (LSTM), transformer, and LSTNet—with MLP serving as the baseline model to forecast water levels. The models are trained using data from 20 distinct river gages across the state of Missouri to ensure consistent performance. Random search optimization is employed for hyperparameter tuning. The prediction intervals are set at 4, 6, 8, and 10 (each interval equivalent to 30 min) to ensure that performance results are robust and not due to random weight initialization or suboptimal hyperparameters and are consistent throughout different prediction intervals. The findings of this study indicate that the LSTNet model leads to a better performance than the other models, with a median RMSE of 0.00724, 0.00959, 0.01204, and 0.01230 for the 4, 6, 8, and 10 intervals, respectively. As climate change leads to localized storms driven by atmospheric shifts, water level fluctuations are becoming increasingly extreme, further exacerbating data drift in real-world datasets. The LSTNet model demonstrates superior performance in terms of RMSE, MAE, and the correlation coefficient across all prediction intervals when forecasting water levels under data drift conditions. Full article

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12 pages, 2245 KiB

Open AccessArticle

Influence of Sub-CMC Rhamnolipid Flushing on the Mobilization and Solubilization of Residual Dodecane in Saturated Porous Media

by Xin Yang, Hua Zhong, Guansheng Liu, Lili Huo and Zonghua Wang

Water 2024, 16(21), 3152; https://doi.org/10.3390/w16213152 - 4 Nov 2024

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Abstract

The potential of monorhamnolipid (monoRL) biosurfactant to enhance the removal of residual dodecane from a porous medium was investigated under monoRL concentration varying from sub-CMC to hyper-CMC conditions by one-dimension column experiments. In the immiscible displacement experiment, 76% of the total volume of [...] Read more.

The potential of monorhamnolipid (monoRL) biosurfactant to enhance the removal of residual dodecane from a porous medium was investigated under monoRL concentration varying from sub-CMC to hyper-CMC conditions by one-dimension column experiments. In the immiscible displacement experiment, 76% of the total volume of dodecane is removed by flushing of 150 μM monoRL solution. The solubilization of dodecane could be enhanced by rhamnolipid even at monorhamnolipid concentrations as low as 50 μM/L. The higher solubilization concentration (500 μM/L) of monoRL solution results in higher solubilized dodecane concentration (160 μM/L) due to the larger quantity of micelle formation. Compared to solubilization, immiscible displacement, or mobilization, is far more effective in removing residual dodecane. The interfacial partitioning tracer tests (IPTT) method is applied to measure the variation in specific dodecane-water interface areas (A_nw). The results showed that the flushing of monoRL increased the A_nw from 2.04 to 3.54 cm²/cm³. This investigation implies that low-concentration monorhamnolipid flushing and subsequent micelle solubilization is an economic method to remediate NAPL-contaminated fields. Full article

(This article belongs to the Special Issue Soil-Groundwater Pollution Investigations)

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16 pages, 4457 KiB

Open AccessArticle

Integration of Coagulation–flocculation(with Natural Coagulant) to Constructed Wetlands for Color Removal from Tequila Vinasses

by Florentina Zurita, Allan Tejeda, Anderson Ramirez-Ramirez and Arturo Montoya

Water 2024, 16(21), 3151; https://doi.org/10.3390/w16213151 - 4 Nov 2024

Viewed by 837

Abstract

The aim of this study was to evaluate a natural coagulant, Moringa oleifera seeds (MOC), to reduce the color concentration in treated tequila vinasses (TVs). TV-A was the effluent of horizontal subsurface flow wetlands (HSSFW); TV-B was the effluent of vertical up-flow wetlands [...] Read more.

The aim of this study was to evaluate a natural coagulant, Moringa oleifera seeds (MOC), to reduce the color concentration in treated tequila vinasses (TVs). TV-A was the effluent of horizontal subsurface flow wetlands (HSSFW); TV-B was the effluent of vertical up-flow wetlands (VUFW); and TV-C was the effluent of vertical down-flow constructed wetlands (VDFW). Raw TVs were also evaluated with MOC. Jar tests were performed to find the optimal dose and pH value for apparent color (AC) removal. With the optimal dose and pH for each type of TV, tests were performed in triplicate to evaluate the removal of apparent color (AC), true color (TC), turbidity, total suspended solids (TSS), chemical oxygen demand (COD), and electrical conductivity (EC). For TV-A and TV-B, the optimal values were 1 g/L of MOC and pH 8, and the removals were 52%, 43%, 50% and 72% of AC, turbidity, TC, and TSS, respectively. For TV-C, the optimal values were 2.5 g/L and pH 5, with removals of 66%, 73%, and 98% for AC, TC, and TSS, respectively. For TV-D, the MOC had no coagulant effect in any of the experimental conditions evaluated, probably due to the high concentration of turbidity and TSS in the raw vinasses, which prevented the interaction between MOC and melanoidins. Deeper studies are required to understand and evaluate those factors that influence MOC efficiency so that the coagulation–flocculation process can be optimized. Full article

(This article belongs to the Special Issue Control and Treatment of Emerging Contaminants in Water Ecosystems)

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15 pages, 2058 KiB

Open AccessArticle

Influence of Salinity Level on the Treatment Performance and Membrane Fouling of MBRs Treating Saline Industrial Effluent

by Majeb Alotaibi, Ashraf Refaat, Faris Munshi, Mohamed Ali El-Said and Saber A. El-Shafai

Water 2024, 16(21), 3150; https://doi.org/10.3390/w16213150 - 4 Nov 2024

Viewed by 502

Abstract

This study investigated the potential impact of salinity levels on the treatment performance and membrane fouling of MBR seeded with sludge from saline industrial effluent treatment plants. A pilot-scale MBR received mixed saline industrial effluents at an organic loading rate (OLR) of 1.3 [...] Read more.

This study investigated the potential impact of salinity levels on the treatment performance and membrane fouling of MBR seeded with sludge from saline industrial effluent treatment plants. A pilot-scale MBR received mixed saline industrial effluents at an organic loading rate (OLR) of 1.3 g COD/L·d and a feed-to-micro-organism (F/M) ratio of 0.33 g COD/g TSS. The effects of the variable salt concentrations of 5, 10, 20, and 25 g/L were investigated. The ranges of ammonia and total nitrogen (TN) concentrations were 22.2–26.3 mgN/L and 55.1–59.2 mgN/L, respectively. The MBR achieved promising results for chemical oxygen demand (COD) and biochemical oxygen demand (BOD), with removal ranges of 95.4–97.2% and 98.3–98.8%, respectively. The system provides 93.2–96.7% and 81.6–92.5% for ammonia and TN removal. Up to a 20 g/L salinity level, there were no significant effects on treatment performance, but 25 g/L significantly declined daily and specific COD removal load. Despite this, residual values at 25 g/L were better and met the Saudi standard for effluent discharge. This is due to membrane fouling which declined the flux rate with a spontaneous reduction of OLR and F/M ratio. The MBR system inoculated with high-salinity-adapted sludge could be managed to release treated effluent that meets Saudi disposal limits by modifying the F/M ratio via reducing the flux or increasing the mixed liquor suspended solid (MLSS) concentration. Full article

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4 pages, 149 KiB

Open AccessEditorial

Impact of Climate and Socio-Economic on Irrigation Water Management and Agricultural Water Productivity

by Xiaojie Li and Chenglong Zhang

Water 2024, 16(21), 3149; https://doi.org/10.3390/w16213149 - 4 Nov 2024

Viewed by 645

Abstract

Water security and food security are fundamental pillars of sustainable social and economic development [...] Full article

(This article belongs to the Special Issue Impact of Climate and Socio-Economic on Irrigation Water Management and Agricultural Water Productivity)

19 pages, 18161 KiB

Open AccessArticle

Numerical Simulation of Flow Fields and Sediment-Induced Wear in the Francis Turbine

by Bing Xue, Yongbo Li, Youping Li, Zhengyang Tang, Bo Xu, Kang Xu, Ziyao Zhou, Zhishun Yu, Bing Yao, Jiayang Pang and Xiaobing Liu

Water 2024, 16(21), 3148; https://doi.org/10.3390/w16213148 - 4 Nov 2024

Viewed by 499

Abstract

Based on the solid–liquid two-phase flow model and the Realizable k-ε Turbulence model, numerical simulations of the sediment–water flow in the flow components of the turbine were conducted. The distribution of sediment-induced wear within the turbine was obtained by analyzing the sediment volume [...] Read more.

Based on the solid–liquid two-phase flow model and the Realizable k-ε Turbulence model, numerical simulations of the sediment–water flow in the flow components of the turbine were conducted. The distribution of sediment-induced wear within the turbine was obtained by analyzing the sediment volume fraction (SVF) and the erosion rate. The results revealed that sediment-induced wear on the stay and guide vanes was primarily distributed along the water inlet edge of the stay and guide vanes. For the runner blades, wear was predominantly localized along the water inlet edge and near the lower ring. The sediment-induced wear patterns on these flow components were found to be consistent with the sediment volume fractions (SVFs) on their surfaces. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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18 pages, 14261 KiB

Open AccessArticle

Multi-Decadal Impact of Mine Waters in Przemsza River Basin, Upper Silesian Coal Basin, Southern Poland

by Ewa Janson

Water 2024, 16(21), 3147; https://doi.org/10.3390/w16213147 - 4 Nov 2024

Viewed by 560

Abstract

Anthropogenic increases in the salinity of surface waters are referred to as secondary salinization. In surface waters, salinity levels can vary significantly due to various natural and anthropogenic influences. This article presents multi-decadal observations of changes in surface water salinity in the highly [...] Read more.

Anthropogenic increases in the salinity of surface waters are referred to as secondary salinization. In surface waters, salinity levels can vary significantly due to various natural and anthropogenic influences. This article presents multi-decadal observations of changes in surface water salinity in the highly industrialized region in southern Poland. The case study of the Przemsza River is an example of the significant impacts of industrial, mainly coal mining, activities that have changed the chemical and biological characteristics of water bodies. The presented research revealed that impacts on salinity and water body status due to mining discharges will be difficult or even impossible to restore, considering the process of transition of the coal sector. In the Przemsza river basin, almost 42% less mine water was discharged in 2023 than in 1991. Parallelly, the salinity of mine waters discharged from deeper levels of active coal mines has increased due to the geochemical gradient (the total load of chlorides and sulfates was 534.8 MgCl⁻+SO₄²⁻ per day in 1991, while in 2023 the total salinity load was 480.1 MgCl⁻+SO₄²⁻ per day). Moreover, of the 19 active mine water discharges in 1991, only 11 remain in 2023, while the observed salinity of surface water in the Przemsza watershed increased rapidly from an average of 2000 µS·cm⁻¹ to 6700 µS·cm⁻¹ due to the significant drought and adverse hydrological conditions, which represent low flows never observed before (three times lower flows in the mouth of the Przemsza River in the period 2021–2023 compared to the previous decades 1991–2020). Impacts on water bodies will continue to occur regardless of mining activities in the area—it should be noted that at the end of exploitation, mine water rebound and flooding do not automatically reduce long-lasting impacts on surface waters. Therefore, salinization is a growing threat that might be amplified by climate change. While industrial and urban impacts on surface water change its characteristics, the future challenge of proper water management with a holistic approach is necessary with proper monitoring data collection and river flow-dependent and surface water salinity-dependent discharge of wastewater in the river basin. Full article

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25 pages, 3248 KiB

Open AccessReview

Nutrient Water Pollution from Unsustainable Patterns of Agricultural Systems, Effects and Measures of Integrated Farming

by Roxana Maria Madjar, Gina Vasile Scăețeanu and Mirela Alina Sandu

Water 2024, 16(21), 3146; https://doi.org/10.3390/w16213146 - 3 Nov 2024

Viewed by 954

Abstract

Nowadays, agricultural practices require special attention due to their important contribution to water pollution, the more so as they are associated with environmental and health impairments. Despite legislation addressing nutrient pollution, there are still high levels of nutrients in water bodies, as evidenced [...] Read more.

Nowadays, agricultural practices require special attention due to their important contribution to water pollution, the more so as they are associated with environmental and health impairments. Despite legislation addressing nutrient pollution, there are still high levels of nutrients in water bodies, as evidenced by the results identified in the literature. Among nutrients of environmental concern identified in water and associated with agricultural practices are nitrogen and phosphorus. When applied in excess under fertilizer form, these nutrients accumulate in water bodies with consequences such as eutrophication or human health impairments if water is used for drinking. The purpose of this review paper is to present the current state of nutrient water pollution generated by unsustainable agricultural practices. In addition, are presented the main legislative regulations addressing water quality imposed by the European Union, are described aspects related to nitrogen and phosphorus pollution from agriculture, and levels of nutrients in water bodies from different European countries. Also, effects of agricultural pollution on the environment and humans are discussed, and possible strategies that could be employed to decrease or prevent water pollution are reviewed. Full article

(This article belongs to the Special Issue The Toxicology and Risk Assessment of Agricultural Runoff and Aquaculture Pollution)

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21 pages, 15270 KiB

Open AccessArticle

Adsorption Removal of Organophosphates from Water by Steel Slag: Modification, Performance, and Energy Site Analysis

by Wei Wu, Yiming Nie, Zhixin Wang, Tianyin Huang, Xiaoyi Xu, Hanhan Liu, Peirong Li and Bingdang Wu

Water 2024, 16(21), 3145; https://doi.org/10.3390/w16213145 - 3 Nov 2024

Viewed by 757

Abstract

Organophosphates are a type of emerging environmental contaminant, which can be removed effectively by adsorption. Here, modified steel slag was examined for its adsorptive performance in the removal of hydroxyethylidene diphosphonic acid (HEDP) from water. Compared to acid (55.3%, maximum removal rate) and [...] Read more.

Organophosphates are a type of emerging environmental contaminant, which can be removed effectively by adsorption. Here, modified steel slag was examined for its adsorptive performance in the removal of hydroxyethylidene diphosphonic acid (HEDP) from water. Compared to acid (55.3%, maximum removal rate) and base (85.5%) modification, high-temperature modification (90.6%) significantly enhanced steel slag’s adsorption capacity for HEDP, surpassing that of unmodified slag (71.2%). Kinetic analyses elucidated a two-phase adsorption process—initial rapid adsorption followed by a slower equilibrium phase. The results of adsorption energy analysis showed that modified steel slag preferentially occupied the sites with higher energy, which promoted the adsorption. After five regeneration cycles, the adsorption properties of the material were not significantly reduced, which indicates that the material has good application potential. Microscopic and spectroscopic techniques, including SEM-EDS, FTIR, and XPS, were employed to uncover the surface chemistry and structural changes responsible for the enhanced adsorption efficiency. The adsorption mechanism of HEDP on steel slag is a complete process guided by hydrogen bonding interactions, strengthened surface complexation, and optimized ligand exchange. This study advances the sustainable utilization of industrial waste materials and contributes significantly to the development of innovative water treatment technologies. Full article

(This article belongs to the Special Issue Urban Water Pollution Control: Theory and Technology)

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12 pages, 4406 KiB

Open AccessArticle

Feasibility Study on Geothermal Dolomite Reservoir Reinjection with Surface Water in Tianjin, China

by Donglin Liu, Yun Cai, Zhaolong Feng, Qiuxia Zhang, Lisha Hu and Shengtao Li

Water 2024, 16(21), 3144; https://doi.org/10.3390/w16213144 - 3 Nov 2024

Viewed by 551

Abstract

Reinjection is thought to be the most effective way to maintain reservoir pressure and production capacity for hydrothermal resources. The use of external water injection to replenish deep geothermal reservoirs is a new approach in China to addressing the problems of declining groundwater [...] Read more.

Reinjection is thought to be the most effective way to maintain reservoir pressure and production capacity for hydrothermal resources. The use of external water injection to replenish deep geothermal reservoirs is a new approach in China to addressing the problems of declining groundwater levels and energy depletion caused by the excessive and uneven exploitation of geothermal resources. However, the key challenge and focus of the feasibility assessment of this method lies in the chemical compatibility of the external water with the native geothermal reservoir water and surrounding rocks. In this paper, we discuss the geochemical response of a dolomite reservoir to lake water injection based on experiments on water–rock interaction in the Wumishan formation in the Dongli Lake area of Tianjin. The results show that after reactions with dolomite, the TDS of the reacted water decreases, indicating the occurrence of precipitation. According to the calculation results obtained using the PHQREEC program, the precipitation amount is found to be quite limited. Geochemical analysis indicates that at the initial stage of the reactions, plagioclase dissolves and releases alkaline metals like Ca-, Na-, SiO₂- and Al-bearing compositions, leading to the oversaturation and precipitation of dolomite and calcite. As the reaction progresses, a portion of the dolomite dissolves, while the calcite continues to precipitate at a later stage. Illite precipitates and its effects on reservoir structure depend on its shape. Based on the experimental data, it can be concluded that the dolomite reservoir will be slightly affected by the reinjection of lake water; however, it is still a good method for the sustainable development of geothermal resources. Full article

(This article belongs to the Section Hydrogeology)

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22 pages, 2875 KiB

Open AccessArticle

Drought Characterization Using Multiple Indices over the Abbay Basin, Ethiopia

by Dessalegn Obsi Gemeda, Béchir Bejaoui, Nasser Farhat, Indale Niguse Dejene, Soreti Fufa Eticha, Tadelu Girma, Tadesse Mosissa Ejeta, Gamachu Biftu Jabana, Gadise Edilu Tufa, Marta Hailemariam Mamo, Zera Kedir Alo, Fedhasa Benti Chalchisa, Jale Amanuel, Getachew Abeshu Disassa, Diribe Makonene Kumsa, Lidiya Dereje Mekonen, Elfenesh Muleta Beyene, Gudetu Wakgari Bortola, Meseret Wagari, Ayantu Habtamu Nemera, Habtamu Tamiru, Dereje Hinew Dehu, Hasen M. Yusuf, Diriba Diba, Solomon Tulu Tadesse and Mitiku Badasa Moisa Show full author list Hide full author list

Water 2024, 16(21), 3143; https://doi.org/10.3390/w16213143 - 3 Nov 2024

Viewed by 906

Abstract

Analyzing agricultural and hydrological drought at different timescales is essential for designing adaptation strategies. This study aimed to assess agricultural and hydrological drought in the Abbay Basin of Ethiopia by using multiple indices, namely the standardized precipitation index (SPI), standardized precipitation evapotranspiration index [...] Read more.

Analyzing agricultural and hydrological drought at different timescales is essential for designing adaptation strategies. This study aimed to assess agricultural and hydrological drought in the Abbay Basin of Ethiopia by using multiple indices, namely the standardized precipitation index (SPI), standardized precipitation evapotranspiration index (SPEI), normalized difference vegetation index (NDVI), vegetation condition index (VCI), and drought severity index (DSI). Climate extremes were assessed over the Abbay Basin between 1981 and 2022. The results indicate that the years 1982 and 2014 were the most drought-prone, while the year 1988 was the wettest year in the Abbay Basin. The results revealed the presence of extremely dry and severely dry conditions, potentially impacting agricultural output in the region. Agricultural drought was identified during the main crop seasons (June to September). The VCI results indicated the presence of extremely wet and severely wet conditions. In 2012, 65% of the area was affected by extreme drought conditions, while nearly half of the Basin experienced extreme drought in 2013 and 2022. The DSI results indicated the occurrence of agricultural drought, although the spatial coverage of extreme dry conditions was lower than that of the other indices. In 2003, 78.49% of the Basin experienced moderate drought conditions, whereas severe drought affected 20% of the region. In 2010, about 90% of the Basin experienced moderate drought. This study provides valuable insights for agricultural communities, enabling them to mitigate the impact of drought on crop yields by utilizing different adaptation strategies. An adequate knowledge of agricultural and hydrological drought is essential for policymakers to assess the potential effects of drought on socioeconomic activities and to recognize the significance of implementing climate change adaptation measures. Full article

(This article belongs to the Section Hydrology)

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16 pages, 6249 KiB

Open AccessArticle

Impact of the Draft Plate on the Wall Erosion and Flow Field Stability of a Cyclone Separator

by Yida Zhang, Xiaodong Zhang and Yanjiao Gao

Water 2024, 16(21), 3142; https://doi.org/10.3390/w16213142 - 3 Nov 2024

Viewed by 637

Abstract

Cyclone separators are commonly employed in the mining, metallurgy and chemical industries due to their simple structure, easy maintenance and high recovery efficiency. However, with the wide application of cyclone separators, many problems have become exposed in their practical operation, restricting their development. [...] Read more.

Cyclone separators are commonly employed in the mining, metallurgy and chemical industries due to their simple structure, easy maintenance and high recovery efficiency. However, with the wide application of cyclone separators, many problems have become exposed in their practical operation, restricting their development. Among these, wall erosion is becoming a significant problem. In this study, to resolve the problem of severe erosion on the walls, the Eulerian–Lagrangian framework was employed to investigate a cyclone separator with a draft plate at the inlet and to evaluate the effect of a draft plate with angles of 0°, 45° and 90° on the degree of erosion and the stabilization of flow fields. Moreover, after verifying the reliability of the numerical model via data from experiments, the characteristics of gas–solid flow were analyzed and the effects of the new structure on the degree of wear were investigated. The results demonstrated that unfavorable phenomena such as secondary flow and wall erosion generated during the operation could be mitigated by the draft plate. When the plate angle was 90°, the wall erosion was the lightest and the range of influence of the secondary flow was the smallest. When the plate angle was 45°, the comprehensive performance was the best, and there was a better balance between the energy loss and the degree of wall erosion. Therefore, the presence of the draft plate has a significant impact on the interaction of gas–solid phases in a cyclone separator. Full article

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

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23 pages, 11815 KiB

Open AccessArticle

Landslide Displacement Prediction Stacking Deep Learning Algorithms: A Case Study of Shengjibao Landslide in the Three Gorges Reservoir Area of China

by Hongwei Jiang, Yunmin Wang, Zizheng Guo, Hao Zhou, Jiayi Wu and Xiaoshuang Li

Water 2024, 16(21), 3141; https://doi.org/10.3390/w16213141 - 2 Nov 2024

Viewed by 739

Abstract

Computational models enable accurate, timely prediction of landslides based on the monitoring data on-site as the development of artificial intelligence technology. The most existing prediction methods focus on finding a single prediction algorithm with excellent performance or an integrated and efficient hyperparameter optimization [...] Read more.

Computational models enable accurate, timely prediction of landslides based on the monitoring data on-site as the development of artificial intelligence technology. The most existing prediction methods focus on finding a single prediction algorithm with excellent performance or an integrated and efficient hyperparameter optimization algorithm with a highly accurate regression prediction algorithm. In order to break through the limitation of generalization of prediction models, this paper proposes an ensemble model that combines deep learning algorithms, with a stacking framework optimized with the sliding window method. Multiple deep learning algorithms are set as the first layer of the stacking framework, which is optimized with the sliding window method to avoid confusion in the time order of datasets based on time series analysis. The Shengjibao landslide in the Three Gorges Reservoir is used as a case study. First, the cumulative displacement is decomposed into a trend and a periodic term using a moving average method. A single-factor and a multi-factor superposition model based on multiple deep learning algorithms are used to predict the trend and periodic term of the displacement, respectively. Finally, the predicted values of the trend and periodic terms are added to obtain the total predicted landslide displacement. For monitoring point ZK2-3, the values of RMSE and MAPE of the total displacement prediction with the stacking model are 15.93 mm and 0.54%, and the values of RMSE and MAPE of the best-performing individual deep learning model are 20.00 mm and 0.64%. The results show that the stacking model outperforms other models by combining the advantages of each individual deep learning algorithm. This study provides a framework for integrating landslide displacement prediction models. It can serve as a reference for the geological disaster prediction and the establishment of an early warning system in the Three Gorges Reservoir Area. Full article

(This article belongs to the Section Hydrogeology)

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23 pages, 72918 KiB

Open AccessArticle

Groundwater Model for Karst and Pelitic Aquifer Systems from a Semi-Arid Region Under Climate Change Scenarios: A Case Study in the Vieira River Watershed, Brazil

by Apolo Pedrosa Bhering, Isabel Margarida Horta Ribeiro Antunes, Gustavo Nascimento Catão, Eduardo Antonio Gomes Marques, Rodrigo Sergio de Paula, Isabella Brito Andrade and Giovana Rebelo Diório

Water 2024, 16(21), 3140; https://doi.org/10.3390/w16213140 - 2 Nov 2024

Viewed by 795

Abstract

Water scarcity is a global issue, especially in semi-arid and arid regions where precipitation is irregularly distributed over time and space. Predicting groundwater flow in heterogeneous karst terrains, which are essential water sources, presents a significant challenge. This article integrates geology, hydrology, and [...] Read more.

Water scarcity is a global issue, especially in semi-arid and arid regions where precipitation is irregularly distributed over time and space. Predicting groundwater flow in heterogeneous karst terrains, which are essential water sources, presents a significant challenge. This article integrates geology, hydrology, and water monitoring to develop a pioneering conceptual and numerical model of groundwater flow in the Montes Claros Region (Vieira River Watershed, Brazil). This model was evaluated under various climate change scenarios, considering changes in rainfall, groundwater consumption, and population growth over the current century. The results indicate that a decline in water table levels is inevitable, primarily driven by population growth and high pumping rates rather than rainfall fluctuations. This underscores the urgent need for improved monitoring, model upgrading, and more importantly, targeted water resource management for Montes Claros. Full article

(This article belongs to the Special Issue Effect of Climate Change and Anthropogenic Activities on Groundwater Resources)

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18 pages, 22321 KiB

Open AccessArticle

Shallow Groundwater Quality Assessment and Pollution Source Apportionment: Case Study in Wujiang District, Suzhou City

by Lili Hou, Qiuju Qi, Quanping Zhou, Jinsong Lv, Leli Zong, Zi Chen, Yuehua Jiang, Hai Yang, Zhengyang Jia, Shijia Mei, Yang Jin, Hong Zhang, Jie Li and Fangfei Xu

Water 2024, 16(21), 3139; https://doi.org/10.3390/w16213139 - 2 Nov 2024

Viewed by 547

Abstract

Groundwater serves as a crucial resource, with its quality significantly impacted by both natural and human-induced factors. In the highly industrialized and urbanized Yangtze River Delta region, the sources of pollutants in shallow groundwater are more complex, making the identification of groundwater pollution [...] Read more.

Groundwater serves as a crucial resource, with its quality significantly impacted by both natural and human-induced factors. In the highly industrialized and urbanized Yangtze River Delta region, the sources of pollutants in shallow groundwater are more complex, making the identification of groundwater pollution sources a challenging task. In this study, 117 wells in Wujiang District of Suzhou City were sampled, and 16 groundwater quality parameters were analyzed. The fuzzy synthetic evaluation method was used to assess the current status of groundwater pollution in the study area; the principal component analysis (PCA) was employed to discern the anthropogenic and natural variables that influence the quality of shallow groundwater; and the absolute principal component scores–multiple linear regression (APCS-MLR) model was applied to quantify the contributions of various origins toward the selected groundwater quality parameters. The results indicate that the main exceeding indicators of groundwater in Wujiang District are I (

28 %

),

N H_{4} - N

(

18 %

), and Mn (

14 %

); overall, the groundwater quality is relatively good in the region, with localized heavy pollution: class IV and class V water are mainly concentrated in the southwest of Lili Town, the north of Songling Town, and the south of Qidu Town. Through PCA, five factors contributing to the hydrochemical characteristics of groundwater in Wujiang District were identified: water–rock interaction, surface water–groundwater interaction, sewage discharge from the textile industry, urban domestic sewage discharge, and agricultural non-point source pollution. Additionally, the APCS-MLR model determined that the contributions of the three main pollution sources to groundwater contamination are in the following order: sewage discharge from the textile industry (

10.63 %

) > urban domestic sewage discharge (

8.69 %

) > agricultural non-point source pollution (

6.26 %

). Full article

(This article belongs to the Special Issue Groundwater Quality and Contamination at Regional Scales)

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19 pages, 5149 KiB

Open AccessArticle

Enhanced Organics Removal Using 3D/GAC/O₃ for N-Containing Organic Pharmaceutical Wastewater: Accounting for Improved Biodegradability and Optimization of Operating Parameters by Response Surface Methodology

by Jun Wei Goh, Raphael Jun Hao Tan, Weiyi Wu, Zhaohong Huang, Say Leong Ong and Jiangyong Hu

Water 2024, 16(21), 3138; https://doi.org/10.3390/w16213138 - 2 Nov 2024

Viewed by 650

Abstract

Pharmaceutical industry effluents often contain high concentrations of refractory organic solvents, chemical oxygen demand (COD), and total dissolved solids (TDSs). These wastewaters, including N-containing organic solvents known for their persistence and toxicity, pose significant environmental challenges. The study evaluated the efficacy of 3D/Granular [...] Read more.

Pharmaceutical industry effluents often contain high concentrations of refractory organic solvents, chemical oxygen demand (COD), and total dissolved solids (TDSs). These wastewaters, including N-containing organic solvents known for their persistence and toxicity, pose significant environmental challenges. The study evaluated the efficacy of 3D/Granular Activated Carbon (GAC)/O₃ treatment compared to linear process additions when treating real pharmaceutical wastewater, and revealed a 2.73-fold enhancement in COD mineralization. The process primarily involves the direct oxidation of monoprotic organic acids found in real pharmaceutical effluents, such as acetic and formic acid, crucially influencing mineralization rates. Optimal conditions determined via the response surface methodology were 125 g/L GAC, 30 mA/cm², and 75 mg/L O₃, achieving high total organic carbon (TOC) and COD removal efficiencies of 87.19 ± 0.19% and 89.67 ± 0.32%, respectively (R² > 0.9), during verification runs. Current density emerged as the key parameter for organic abatement, aligning with the emphasis on direct oxidation at the anode surface. This integrated approach enhances biodegradability (BOD₅/COD) and reduces acute toxicity associated with persistent N-containing solvents, demonstrating promising applications in pharmaceutical wastewater treatment. Full article

(This article belongs to the Special Issue Advancement of Advanced Oxidation Processes (AOPs) for Water and Wastewater Treatment and Water Reuse)

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13 pages, 4097 KiB

Open AccessArticle

The Influence of Fibers from Domestic Laundry Wastewater on the Clogging Process of a Filter

by Jakub Nieć, Natalia Walczak, Marcin Spychała and Zbigniew Walczak

Water 2024, 16(21), 3137; https://doi.org/10.3390/w16213137 - 2 Nov 2024

Viewed by 673

Abstract

This study presents the impact of the size and shape of particles in laundry wastewater on the clogging process of a porous material. Clogging can be defined as a mechanical limitation of flow through porous media. The process of mechanical clogging was investigated [...] Read more.

This study presents the impact of the size and shape of particles in laundry wastewater on the clogging process of a porous material. Clogging can be defined as a mechanical limitation of flow through porous media. The process of mechanical clogging was investigated in this study. The research was conducted in laboratory conditions in a filter column filled with glass beads whose diameter corresponded to coarse sand. The results reveal the influence of graywater quality on filter hydraulic conductivity and bed clogging, showing the impact of fiber particles in wastewater (sewage from home laundry) on the clogging process in soil. The results confirm that fiber particles significantly reduce filter permeability, particularly due to the formation of a filter cake. As analyzed in this paper, the distribution of quantitative data on particles of different sizes found in laundry wastewater indicates that they mainly accumulate in the upper layer, where particles with fiber lengths ranging from 0 to 1600 µm can be found. The average length of the fibers decreased with increasing depth. At a depth of approximately 10 cm, fibers with dimensions in the range of 0 to 100 μm were predominantly observed. Full article

(This article belongs to the Section Soil and Water)

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21 pages, 7072 KiB

Open AccessArticle

Investigating the Influence of Vegetation Height on the Air Concentration of Supercritical Aerated Flows

by Anne Mozer and S. Harish

Water 2024, 16(21), 3136; https://doi.org/10.3390/w16213136 - 1 Nov 2024

Viewed by 655

Abstract

Spillways can present a way to control the overflowing of water during flood events and prevent damage from levee breaches. With increasing interest in nature-based solutions, the interaction between flow and vegetation parameters has to be understood. Aeration usually occurs during the overflow [...] Read more.

Spillways can present a way to control the overflowing of water during flood events and prevent damage from levee breaches. With increasing interest in nature-based solutions, the interaction between flow and vegetation parameters has to be understood. Aeration usually occurs during the overflow of sloped spillways, leading to the bulking of flow, alterations of flow characteristics, and energy dissipation. The influence of the vegetation parameter on aerated flow characteristics has not yet been investigated in greater detail; no systematic investigation of the effect of vegetation parameters has been conducted. This paper aims to systematically analyze the influence of different vegetation heights on air entrainment during the overflow of spillways. Therefore, a spillway model with a slope of 18° (1:3) was equipped with artificial turf of varying turf heights, and supercritical flows were investigated. The aeration was measured using double-tip conductivity probes, giving insights into air concentration profiles, bubble count rates, estimations of energy dissipation, and flow velocities. The results highlighted the significant influence of vegetation height on the aeration process. Higher air concentrations over the flow depth were observed for higher turf heights tested in this study. Also, the energy dissipation and flow velocity reduction increased with higher vegetation heights. Overall, the present study uncovers the effect of vegetated covers, thereby contributing to the fundamentals of aerated flows. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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13 pages, 1882 KiB

Open AccessArticle

Coastline Bathymetry Retrieval Based on the Combination of LiDAR and Remote Sensing Camera

by Yicheng Liu, Tong Wang, Qiubao Hu, Tuanchong Huang, Anmin Zhang and Mingwei Di

Water 2024, 16(21), 3135; https://doi.org/10.3390/w16213135 - 1 Nov 2024

Viewed by 619

Abstract

This paper presents a Compact Integrated Water–Land Survey System (CIWS), which combines a remote sensing camera and a LiDAR module, and proposes an innovative underwater topography retrieval technique based on this system. This technique utilizes high-precision water depth points obtained from LiDAR measurements [...] Read more.

This paper presents a Compact Integrated Water–Land Survey System (CIWS), which combines a remote sensing camera and a LiDAR module, and proposes an innovative underwater topography retrieval technique based on this system. This technique utilizes high-precision water depth points obtained from LiDAR measurements as control points, and integrating them with the grayscale values from aerial photogrammetry images to construct a bathymetry retrieval model. This model can achieve large-scale bathymetric retrieval in shallow waters. Calibration of the UAV-mounted LiDAR system was conducted using laboratory and Dongjiang Bay marine calibration fields, with the results showing a laser depth measurement accuracy of up to 10 cm. Experimental tests near Miaowan Island demonstrated the generation of high-precision 3D seabed topographic maps for the South China Sea area using LiDAR depth data and remote sensing images. The study validates the feasibility and accuracy of this integrated scanning method for producing detailed 3D seabed topography models. Full article

(This article belongs to the Special Issue Application of Remote Sensing for Coastal Monitoring)

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18 pages, 14492 KiB

Open AccessArticle

Partitioning of Heavy Rainfall in the Taihang Mountains and Its Response to Atmospheric Circulation Factors

by Qianyu Tang, Zhiyuan Fu, Yike Ma, Mengran Hu, Wei Zhang, Jiaxin Xu and Yuanhang Li

Water 2024, 16(21), 3134; https://doi.org/10.3390/w16213134 - 1 Nov 2024

Viewed by 605

Abstract

The spatial and temporal distribution of heavy rainfall across the Taihang Mountains exhibits significant variation. Due to the region’s unstable geological conditions, frequent heavy rainfall events can lead to secondary disasters such as landslides, debris flows, and floods, thus intensifying both the frequency [...] Read more.

The spatial and temporal distribution of heavy rainfall across the Taihang Mountains exhibits significant variation. Due to the region’s unstable geological conditions, frequent heavy rainfall events can lead to secondary disasters such as landslides, debris flows, and floods, thus intensifying both the frequency and severity of extreme events. Understanding the spatiotemporal evolution of heavy rainfall and its response to atmospheric circulation patterns is crucial for effective disaster prevention and mitigation. This study utilized daily precipitation data from 13 meteorological stations in the Taihang Mountains spanning from 1973 to 2022, employing Rotated Empirical Orthogonal Function (REOF), the Mann–Kendall Trend Test, and Continuous Wavelet Transform (CWT) to examine the spatiotemporal characteristics of heavy rainfall and its relationship with large-scale atmospheric circulation patterns. The results reveal that: (1) Heavy rainfall in the Taihang Mountains can be categorized into six distinct regions, each demonstrating significant spatial heterogeneity. Region I, situated in the transition zone between the plains and mountains, experiences increased rainfall due to orographic lifting, while Region IV, located in the southeast, receives the highest rainfall, driven primarily by monsoon lifting. Conversely, Regions III and VI receive comparatively less precipitation, with Region VI, located in the northern hilly area, experiencing the lowest rainfall. (2) Over the past 50 years, all regions have experienced an upward trend in heavy rainfall, with Region II showing a notable increase at a rate of 14.4 mm per decade, a trend closely linked to the intensification of the hydrological cycle driven by global warming. (3) The CWT results reveal significant 2–3-year periodic fluctuations in rainfall across all regions, aligning with the quasi-biennial oscillation (QBO) characteristic of the East Asian summer monsoon, offering valuable insights for future climate predictions. (4) Correlation and wavelet coherence analyses indicate that rainfall in Regions II, III, and IV is positively correlated with the Southern Oscillation Index (SOI) and the Pacific Warm Pool (PWP), while showing a negative correlation with the Pacific Decadal Oscillation (PDO). Rainfall in Region I is negatively correlated with the Indian Ocean Dipole (IOD). These climatic factors exhibit a lag effect on rainfall patterns. Incorporating these climatic factors into future rainfall prediction models is expected to enhance forecast accuracy. This study integrates REOF analysis with large-scale circulation patterns to uncover the complex spatiotemporal relationships between heavy rainfall and climatic drivers, offering new insights into improving heavy rainfall event forecasting in the Taihang Mountains. The complex topography of the Taihang Mountains, combined with unstable geological conditions, leads to uneven spatial distribution of heavy rainfall, which can easily trigger secondary disasters such as landslides, debris flows, and floods. This, in turn, further increases the frequency and severity of extreme events. Full article

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

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27 pages, 2540 KiB

Open AccessArticle

Forecasting Multi-Step Soil Moisture with Three-Phase Hybrid Wavelet-Least Absolute Shrinkage Selection Operator-Long Short-Term Memory Network (moDWT-Lasso-LSTM) Model

by W. J. M. Lakmini Prarthana Jayasinghe, Ravinesh C. Deo, Nawin Raj, Sujan Ghimire, Zaher Mundher Yaseen, Thong Nguyen-Huy and Afshin Ghahramani

Water 2024, 16(21), 3133; https://doi.org/10.3390/w16213133 - 1 Nov 2024

Viewed by 766

Abstract

To develop agricultural risk management strategies, the early identification of water deficits during the growing cycle is critical. This research proposes a deep learning hybrid approach for multi-step soil moisture forecasting in the Bundaberg region in Queensland, Australia, with predictions made for 1-day, [...] Read more.

To develop agricultural risk management strategies, the early identification of water deficits during the growing cycle is critical. This research proposes a deep learning hybrid approach for multi-step soil moisture forecasting in the Bundaberg region in Queensland, Australia, with predictions made for 1-day, 14-day, and 30-day, intervals. The model integrates Geospatial Interactive Online Visualization and Analysis Infrastructure (Giovanni) satellite data with ground observations. Due to the periodicity, transience, and trends in soil moisture of the top layer, time series datasets were complex. Hence, the Maximum Overlap Discrete Wavelet Transform (moDWT) method was adopted for data decomposition to identify the best correlated wavelet and scaling coefficients of the predictor variables with the target top layer moisture. The proposed 3-phase hybrid moDWT-Lasso-LSTM model used the Least Absolute Shrinkage and Selection Operator (Lasso) method for feature selection. Optimal hyperparameters were identified using the Hyperopt algorithm with deep learning LSTM method. This proposed model’s performances were compared with benchmarked machine learning (ML) models. In total, nine models were developed, including three standalone models (e.g., LSTM), three integrated feature selection models (e.g., Lasso-LSTM), and three hybrid models incorporating wavelet decomposition and feature selection (e.g., moDWT-Lasso-LSTM). Compared to alternative models, the hybrid deep moDWT-Lasso-LSTM produced the superior predictive model across statistical performance metrics. For example, at 1-day forecast, The moDWT-Lasso-LSTM model exhibits the highest accuracy with the highest

R^{2} \approx 0.92469

and the lowest RMSE

\approx 0.97808

, MAE

\approx 0.76623

, and SMAPE

\approx 4.39700

%, outperforming other models. The moDWT-Lasso-DNN model follows closely, while the Lasso-ANN and Lasso-DNN models show lower accuracy with higher RMSE and MAE values. The ANN and DNN models have the lowest performance, with higher error metrics and lower R2 values compared to the deep learning models incorporating moDWT and Lasso techniques. This research emphasizes the utility of the advanced complementary ML model, such as the developed moDWT-Lasso-LSTM 3-phase hybrid model, as a robust data-driven tool for early forecasting of soil moisture. Full article

(This article belongs to the Section Soil and Water)

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21 pages, 2732 KiB

Open AccessReview

Comprehensive Control of Water Quality Deterioration in Building Water Supply Systems: A Review on Configuration, Purification and Regulation

by Na Li, Yong-Wang Liu, Xing Li, Xiao-Yan Fan, Nan Wang and Li Zhao

Water 2024, 16(21), 3132; https://doi.org/10.3390/w16213132 - 1 Nov 2024

Viewed by 888

Abstract

The overall goal of urban water supply is to ensure the water quality from source to tap. As the “last mile”, the building water supply system (BWSS) is the crucial part in ensuring tap water safety, and its deteriorating water quality has attracted [...] Read more.

The overall goal of urban water supply is to ensure the water quality from source to tap. As the “last mile”, the building water supply system (BWSS) is the crucial part in ensuring tap water safety, and its deteriorating water quality has attracted increasing attention. In this work, we provide a comprehensive overview of the pollution, configuration, purification and regulation of BWSSs, with a focus on ensuring water quality safety. Periodic water usage in buildings is a unique feature that leads to intermittent water stagnation and reduced residual chlorine. Biological pollution has become a key focus of existing studies due to its acute effects on human health, compared to the chronic effects of chemical pollution. For new systems, water quality risks can be reduced at the source by optimizing pipe materials and reasonable layout. It is recommended to introduce secondary disinfection technologies, as they are important for ensuring biosecurity. Moreover, supervision and maintenance are the basis for long-term efficient operation of BWSSs. This review constructs a framework for controlling water quality deterioration based on the wholse process, which is instructive for the design, operation, maintenance and management of BWSSs, and provides relatively clear research directions for improving water quality. Full article

(This article belongs to the Section Urban Water Management)

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13 pages, 781 KiB

Open AccessArticle

The Legal Personhood as an Instrumental Tool for Reforming the Governance of the Rhône River

by Cyrille Vallet, Christian Bréthaut and Michel Lussault

Water 2024, 16(21), 3131; https://doi.org/10.3390/w16213131 - 1 Nov 2024

Viewed by 761

Abstract

Legal personhood has been recognized for several ecosystems worldwide, garnering significant attention from the scholarly community. This attention translated with the mobilization of approaches anchored into legal, institutional, or ethnographic perspectives. On-going calls for the recognition of Rhone River’s legal personhood provides us [...] Read more.

Legal personhood has been recognized for several ecosystems worldwide, garnering significant attention from the scholarly community. This attention translated with the mobilization of approaches anchored into legal, institutional, or ethnographic perspectives. On-going calls for the recognition of Rhone River’s legal personhood provides us the opportunity to analyze on-going processes in a transboundary river located in the middle of Europe. This paper focuses on how such a concept gets promoted and intends to make its way on the political agenda. Specifically, we examine two current promoters of the legal personhood of the Rhone River: the International Commission for the Protection of Lake Geneva (CIPEL) and ID-Eau. We identify five key lessons: (1) the request for recognition of legal personhood derives from actors’ willingness to change current governance practices and to shift the productivist paradigm towards more decentralized and inclusive governance system; (2) legal personhood is presented as a solution to problems that have not yet been clearly framed nor identified, opening up thinking on how such concept may be instrumentalized; (3) the discussion remains limited to a small number of experts; (4) the legitimacy of this debate requires scrutiny; (5) the legal personhood concept should be reinterpreted to fit within Western ontologies. Full article

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

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19 pages, 13432 KiB

Open AccessArticle

Analysis of the Occurrence Conditions and Formation Mechanism of Mineral Water in the Southern Region of Yaoquan Mountain, Wudalianchi

by Chang Li, Xubin Shan, Chuansheng Li, Shuren Hao, Bin Cheng, Chuanlei Lu, Jian Zhao, Xu Wang and Ziliang Su

Water 2024, 16(21), 3130; https://doi.org/10.3390/w16213130 - 1 Nov 2024

Viewed by 540

Abstract

Because of its unique geographical properties, the Yaoquanshan area of Wudalianchi City, Heilongjiang Province, contains rich mineral water resources. We have carried out much research on the mineral water in the Yaoquanshan area of Wudalianchi City, which has also been supplemented by of [...] Read more.

Because of its unique geographical properties, the Yaoquanshan area of Wudalianchi City, Heilongjiang Province, contains rich mineral water resources. We have carried out much research on the mineral water in the Yaoquanshan area of Wudalianchi City, which has also been supplemented by of previous studies. In this paper, through a controlled audio geoelectromagnetic method, geological drilling, groundwater level monitoring and water quality analysis, the structure, regional geology, hydrogeology and water geochemistry, as well as the characteristics of the distribution of metasilicate mineral water and natural soda water, the formation mechanism and the recharge, runoff and excretion of groundwater in the study area, are discussed. The results can provide a theoretical basis for the exploitation and utilization of mineral water resources in the southern region of the Wudalianchi Pharmaceutical Spring Mountain. 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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13 pages, 8412 KiB

Open AccessArticle

Grain Size in an Alpine Lake from the Chinese Loess Plateau: Implications for Paleofloods and East Asian Summer Monsoon Variability

by Chao Zhang, Keke Yu, Aizhen Li, Tianao Li and Suyue Xin

Water 2024, 16(21), 3129; https://doi.org/10.3390/w16213129 - 1 Nov 2024

Viewed by 468

Abstract

Reliable paleoflood proxies can help reconstruct past flood variation patterns. Here, we investigated the grain-size data of a 63 cm core retrieved from Lake Chaonaqiu, western Chinese Loess Plateau, in order to build a long time-series of flood occurrence from sedimentology that extends [...] Read more.

Reliable paleoflood proxies can help reconstruct past flood variation patterns. Here, we investigated the grain-size data of a 63 cm core retrieved from Lake Chaonaqiu, western Chinese Loess Plateau, in order to build a long time-series of flood occurrence from sedimentology that extends the period of instrumental data. Our results indicate that three parameters (mean, standard deviation and grain-size ratio of 16–63/2–16 μm) are sensitive to hydrodynamic changes in Lake Chaonaqiu, which are further linked to high-energy inflow associated with high-intensity rainfall or flood events. These three parameters’ variations were well correlated with the precipitation records reconstructed from tree-rings and historical documents in neighboring regions and overlapped with 109 historical flood events from historical documents in counties around the lake for the past 300 years. Therefore, we propose that the grain size in the sediments of Lake Chaonaqiu is a reliable paleoflood proxy. The sensitivity of flood signals to grain size may be related to the precipitation and vegetation cover in the catchment of the lake, which are further linked to the strength of the East Asian summer monsoon. Full article

(This article belongs to the Special Issue Urban Flood Frequency Analysis and Risk Assessment)

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19 pages, 7115 KiB

Open AccessArticle

N-Chloramine Functionalized Polymer Gels for Point-of-Use Water Disinfection

by Ana Estrella-You, Israt Jahan Duti, Qinmo Luo, Jamie D. Harris, Rachel A. Letteri and James A. Smith

Water 2024, 16(21), 3128; https://doi.org/10.3390/w16213128 - 1 Nov 2024

Viewed by 704

Abstract

Combinations of metal disinfectants (i.e., silver and copper) with chlorine in doses that meet the World Health Organization guidelines for drinking water operate synergistically to provide superior drinking water disinfection across a wide range of pathogens. Moreover, the combination of disinfectants allows for [...] Read more.

Combinations of metal disinfectants (i.e., silver and copper) with chlorine in doses that meet the World Health Organization guidelines for drinking water operate synergistically to provide superior drinking water disinfection across a wide range of pathogens. Moreover, the combination of disinfectants allows for lower chlorine levels and a less objectionable taste and odor to the treated water (some people can taste or smell chlorine at concentrations as low as 300 μg/L). Towards chlorine-releasing materials for combination with silver- or copper-releasing materials in point-of-use water disinfection, N-chloramine containing polymer gels were developed and their potential for E. coli bacteria inactivation was assessed in deionized water that contained salts to simulate groundwater. Following the chlorination of gels containing chloramine precursors, these gels capably inactivated E. coli, achieving log₁₀ reductions—depending on the gel mass—ranging from 1.1 to 4.5. While chlorine released from the gels was not spectroscopically detected, free chlorine solutions inactivated E. coli in a concentration-dependent way, with 5 and 20 μg/L Cl₂ yielding log₁₀ reductions of 0.43 and 1.69, respectively, suggesting that low levels of chlorine, below both the limit of detection of spectroscopic assays (ca. 40 μg/L Cl₂) and levels known to create adverse taste and smell, are sufficient to inactivate bacteria. Unchlorinated gels or chlorinated control styrene gels (without chloramine precursor) did not inactivate bacteria, suggesting that disinfection did not come from the precursor or from chlorine trapped in the gels after chlorination. In addition, these gels were evaluated together with the MadiDrop (MD, a commercial silver-ceramic tablet) and a copper screen that release silver and copper disinfectants, respectively. Combinations of the gel and MD produced E. coli inactivation close to 2-log₁₀ reduction, with the combination, gels alone, and MD alone achieving 1.86-, 1.10-, and 0.69-log₁₀ reduction, respectively. When the gels were combined with the copper screen, however, neither an increase nor a decrease in bacterial reduction was observed compared to that achieved with the gels alone. The laboratory results in this study are promising and suggest the potential for chloramine-functionalized gels to serve as an alternative to existing commercial chlorine-based POU technologies and in combination with silver-based POU technologies. Full article

(This article belongs to the Special Issue New Perspectives for Water Quality and Wastewater Remediation: Advanced Oxidation Processes and Toxicity Assessments)

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