Water

21 pages, 2056 KiB

Open AccessArticle

Application of Adaptive ε-IZOA-Based Optimization Algorithm in the Optimal Scheduling of Reservoir Clusters

by Haitao Chen, Nishi Chu and Aiqing Kang

Water 2025, 17(9), 1274; https://doi.org/10.3390/w17091274 - 24 Apr 2025

: Increasing environmental variability and operational complexity in reservoir systems necessitate advanced optimization frameworks for flood control. This study proposes the ε-constrained Improved Zebra Optimization Algorithm (ε-IZOA), a novel metaheuristic algorithm integrating an enhanced Zebra Optimization Algorithm (ZOA) with adaptive ε-constraint handling, to [...] Read more.

: Increasing environmental variability and operational complexity in reservoir systems necessitate advanced optimization frameworks for flood control. This study proposes the ε-constrained Improved Zebra Optimization Algorithm (ε-IZOA), a novel metaheuristic algorithm integrating an enhanced Zebra Optimization Algorithm (ZOA) with adaptive ε-constraint handling, to address multi-reservoir flood control optimization. Three strategic modifications advance the standard ZOA: (1) Bernoulli chaotic mapping for diversified population initialization; (2) adaptive weight balancing for exploration-exploitation trade-off mitigation; and (3) golden sinusoidal vectorization for global search refinement, collectively forming the Improved ZOA (IZOA). The ε-IZOA synergizes IZOA with ε-dominance criteria to dynamically resolve constrained optimization conflicts. Applied to the Yellow River Basin’s five-reservoir cascade, ε-IZOA achieves a 52.97% peak shaving rate at Huayuankou Station, reducing the maximum discharge to 18,745.02 m³/s—a performance surpassing benchmark methods. The algorithm’s success stems from its bio-inspired hybrid architecture, which embeds swarm intelligence principles into nonlinear constraint management. This work establishes ε-IZOA as a computationally robust tool for large-scale reservoir optimization, with implications for mitigating flood risks in climate-sensitive basins. Future research should prioritize its integration with real-time hydrological forecasting systems. Full article

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

17 pages, 9834 KiB

Open AccessArticle

Efficient Digital-Elevation-Model-Based Flow Direction Estimation Using Priority Queue with Flow Distance and Zigzag Route Considerations

by Pengfei Wu, Jintao Liu, Kaili Xv and Xiaole Han

Water 2025, 17(9), 1273; https://doi.org/10.3390/w17091273 - 24 Apr 2025

Abstract

Extracting drainage networks from a digital elevation model (DEM) with massive cells is time-consuming due to depressions and flats, where flow paths to the outlet cannot be extracted using downslope gradients. Algorithms based on a priority queue are an efficient solution for this [...] Read more.

Extracting drainage networks from a digital elevation model (DEM) with massive cells is time-consuming due to depressions and flats, where flow paths to the outlet cannot be extracted using downslope gradients. Algorithms based on a priority queue are an efficient solution for this task. However, the existing algorithms depend on the insertion order in a priority queue to determine flow directions for cells with equal elevation. This dependency increases the sorting time in the priority queue. Our study developed an improved algorithm (referred to as DZFlood), adopting a dual priority queue. The queue considers elevation and flow distance to outlets. Cells sharing equal elevation and flow distance can be randomly arranged to reduce time costs. A secondary correction is applied to select a more tortuous yet shortest flow path for each flat cell. The visual assessment results show that the flow paths derived by DZFlood are more accurate than five existing algorithms and consistent with the real rivers and lakes. The computation efficiency of DZFlood is 19.2% faster, on average, than that of another priority-queue-based algorithm named LCP. The relative difference between their runtimes is greater when a larger DEM is used. Over a DEM with 3 × 10⁸ cells, DZFlood performs at least 28% faster than LCP. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

16 pages, 3837 KiB

Open AccessArticle

Optimizing the Coordinated Regulation of Storage and Discharge Across Regions in Plain City Under Extreme Rainfall Scenarios

by Liangrui Yang, Zhiming Zhang, Qianting Liu and Zhe Wang

Water 2025, 17(9), 1272; https://doi.org/10.3390/w17091272 - 24 Apr 2025

Abstract

Under excessive rainfall conditions, achieving Coordinated Regulation of Storage and Discharge (CRSD) across different regions can effectively reduce the overall risk of urban flooding. This study proposes three water gate control modes: no control, unified control, and independent control, taking the Lingang New [...] Read more.

Under excessive rainfall conditions, achieving Coordinated Regulation of Storage and Discharge (CRSD) across different regions can effectively reduce the overall risk of urban flooding. This study proposes three water gate control modes: no control, unified control, and independent control, taking the Lingang New Area as a case study, based on the differences in regional storage and discharge capacities, and evaluating the effectiveness of the three control modes through the model. The results show that both the unified control and independent control models significantly outperform the no control model in terms of total overflow volume control. When compared to each other, the unified control model is more suitable for overall drainage coordination across the system, while the independent control model is better suited for prioritizing the protection of specific regions, emphasizing the importance of identifying gate response thresholds. Full article

(This article belongs to the Section Urban Water Management)

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17 pages, 2975 KiB

Open AccessArticle

Eliminating Noise of Pumping Test Data Using the Theis Solution Implemented in the Kalman Filter

by Maria Ines Rivas-Recendez, Hugo Enrique Júnez-Ferreira, Julián González-Trinidad, Carlos Alberto Júnez-Ferreira, Raúl Ulices Silva-Ávalos and Eric Muñoz de la Torre

Water 2025, 17(9), 1271; https://doi.org/10.3390/w17091271 - 24 Apr 2025

Abstract

This study presents a novel approach that integrates the Kalman filter and genetic algorithms to obtain the hydraulic parameters of a confined aquifer with precision, eliminating noise that is not normally considered in traditional procedures; these parameters are necessary for the design of [...] Read more.

This study presents a novel approach that integrates the Kalman filter and genetic algorithms to obtain the hydraulic parameters of a confined aquifer with precision, eliminating noise that is not normally considered in traditional procedures; these parameters are necessary for the design of wells, the calculation of water balances and the numerical modeling of aquifers. The Theis solution for horizontal radial groundwater flow to an extraction well within a confined aquifer is implemented in the Kalman filter to calibrate the hydraulic transmissivity and the storage coefficient, minimizing the differences between drawdown estimates and the Theis solution by means of genetic algorithms. The estimate error variances provided by the method allowed for the quantification of an approximate average drawdown measurement error of 0.12 m and 0.02 m, respectively, during the execution of two pumping tests. Full article

(This article belongs to the Topic Advances in Hydrogeological Research)

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15 pages, 4860 KiB

Open AccessArticle

Estimation of Reclaimed Water Utilization Benefits in a Typical Coastal River Network

by Lei Fu, Rongxiang Hu, Junmin Wang, Qiaoqiao Jin, Shiwu Wang and Chao Jiang

Water 2025, 17(9), 1270; https://doi.org/10.3390/w17091270 - 24 Apr 2025

Abstract

Nowadays, reclaimed water is widely acknowledged as a convincing alternative to fresh water resources, with it also recognized as an important material in water diversion projects around the world. As a typical coastal area, Taizhou city, located in southeast China, is close to [...] Read more.

Nowadays, reclaimed water is widely acknowledged as a convincing alternative to fresh water resources, with it also recognized as an important material in water diversion projects around the world. As a typical coastal area, Taizhou city, located in southeast China, is close to the East China Sea. In this study, the benefits of reclaimed water utilization in a water diversion project are estimated, and both field monitoring and numerical simulation are executed to demonstrate the improvements in the local plain river network water quantity and quality. The highly developed domestic society and economy have led to a huge contradiction between water supply and demand. As a result, the coastal plain river network in Taizhou city is always plagued by low flow velocity and poor water quality. The utilization of reclaimed water in Taizhou city has been proven to be efficient and effective for the local development and environment in this study, and it will be a good tool for the coastal plain river network in improving both the water quantity and quality in the future for those cities close to the shore area. Full article

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

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15 pages, 2136 KiB

Open AccessArticle

Removal of Indicator Micropollutants Included in Directive (EU) 2024/3019 Using Nanofiltration and Reverse Osmosis

by Elizabeta Domínguez, Marta Ferre, María José Moya-Llamas, Nuria Ortuño and Daniel Prats

Water 2025, 17(9), 1269; https://doi.org/10.3390/w17091269 - 24 Apr 2025

Abstract

Contaminants of emerging concern (CECs) comprise a diverse group of substances whose presence in the environment is of increasing concern due to their potential negative effects on human health and the environment. Multiple studies have concluded that nanofiltration (NF) and reverse osmosis (RO) [...] Read more.

Contaminants of emerging concern (CECs) comprise a diverse group of substances whose presence in the environment is of increasing concern due to their potential negative effects on human health and the environment. Multiple studies have concluded that nanofiltration (NF) and reverse osmosis (RO) membrane separation mechanisms are effective barriers for organic pollutants, showing generally high removal efficiency. In this study, nine indicator CECs included in the Directive (EU) 2024/3019 concerning urban wastewater treatment were selected and used as a reference to calculate the removal percentage of all micropollutants present in the influent of wastewater treatment plants (WWTPs). According to the regulations, a minimum average removal percentage of 80% of the influent load must be achieved by analyzing at least six out of a set of twelve micropollutants, including those considered in this study. The treatments were conducted using three commercial RO membranes and one commercial NF membrane. Our findings indicate that membrane technology alone can remove over 80% of the micropollutants studied, except benzotriazole. An analysis of the separation mechanisms was carried out to understand the performance of each CEC in relation to each membrane type, taking into account pollutant physicochemical properties and observed removal efficiencies. Full article

(This article belongs to the Special Issue Physical–Chemical Wastewater Treatment Technologies)

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21 pages, 1772 KiB

Open AccessArticle

Determination of Temporary Hubs Locations Along a River in Case of Flood

by Suhad Rebhi Al-Natoor, Gergely Kovács, Zoltán Lakner and Béla Vizvári

Water 2025, 17(9), 1268; https://doi.org/10.3390/w17091268 - 24 Apr 2025

Abstract

Due to global climate change, the frequency and intensity of floods will be increasing in the decades to come. Under these conditions, there is an urgent need to develop such relatively simple and robust models and methods, which help the logistical preparatory and [...] Read more.

Due to global climate change, the frequency and intensity of floods will be increasing in the decades to come. Under these conditions, there is an urgent need to develop such relatively simple and robust models and methods, which help the logistical preparatory and crisis management work in case of this natural disaster. In the crisis management phase, the integrated complex command centers and logistical hubs play an essential role. It is an open-ended question: how do we determine the optimal location of these hubs, and find an optimal compromise between their radius of supply and vulnerability? The current article presents a simple and fast method to determine the optimal position of hubs, minimizing their vulnerability, in cases when there is no chance to control the flood of the river (no dam), and in cases when there is a natural or artificial barrier, preventing the flow of water (dam scenario). Based on a system of equations, applying the Gumbel distribution of maximal water levels in various years, the article offers numerical examples to prove the simplicity and practical applicability of the method developed. This approach can supply a decision support system, based on AI. The paper concludes with policy implications. Full article

(This article belongs to the Special Issue Hydrological Simulation and Forecasting Based on Artificial Intelligence)

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21 pages, 1209 KiB

Open AccessArticle

Achieving Water and Energy Independence, Economic Sustainability, and CO₂ Reduction Through Hybrid Renewable Systems: A Case Study of Skyros Island

by Athanasios-Foivos Papathanasiou and Evangelos Baltas

Water 2025, 17(9), 1267; https://doi.org/10.3390/w17091267 - 24 Apr 2025

Abstract

This study explores the challenge of achieving water and energy self-sufficiency in isolated regions through the design a hybrid renewable energy system (HRES) for Skyros, a Greek island not connected to the mainland grid. The proposed system integrates wind turbines, photovoltaics, pumped hydro, [...] Read more.

This study explores the challenge of achieving water and energy self-sufficiency in isolated regions through the design a hybrid renewable energy system (HRES) for Skyros, a Greek island not connected to the mainland grid. The proposed system integrates wind turbines, photovoltaics, pumped hydro, and hydrogen storage to ensure a stable supply, particularly during peak summer demand. Using advanced R simulations, three scenarios were analyzed on a 30 min basis. A combined storage system meets 99.99% of water demand and 83% of electricity needs. A pumped hydro-only system covers 99.99% of water demand and 74% of electricity needs. A hydrogen-only system supplies 99.99% of water demand but just 67% of electricity needs. The findings indicate annual CO₂ emission reductions exceeding 9600 tons. Economic analysis confirms the system’s feasibility, with a projected 10-year payback period. The cost of desalinated water is estimated at EUR 1/m³, while energy costs range from EUR 0.083/kWh for pumped hydro to EUR 0.093/kWh for hydrogen storage and EUR 0.101/kWh for the combined system. Overall, the results highlight the potential of hydrogen storage to enhance system flexibility and complement pumped hydro, offering sustainable water and energy solutions for isolated regions while addressing both environmental and economic challenges. Full article

(This article belongs to the Section Water-Energy Nexus)

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9 pages, 2090 KiB

Open AccessArticle

Preparation of Triiodide Resin Using Potassium Iodide and Peracetic Acid: Application to Wastewater Treatment

by Hyun-Jin Lim, Ji-Yeon Kang, Ga-Hyeon Kim and Jong-Hee Kwon

Water 2025, 17(9), 1266; https://doi.org/10.3390/w17091266 - 24 Apr 2025

Abstract

Triiodide resin has an antimicrobial effect on bacteria in water. In the traditional TR manufacturing method, potassium iodide (KI) and crystalline I₂ are reacted to form triiodide ion (I₃⁻). However, I₂ is difficult to use and store because [...] Read more.

Triiodide resin has an antimicrobial effect on bacteria in water. In the traditional TR manufacturing method, potassium iodide (KI) and crystalline I₂ are reacted to form triiodide ion (I₃⁻). However, I₂ is difficult to use and store because it is vaporizable and poorly soluble in water. This study was conducted to develop a method of producing triiodide resin (TR) without using crystalline I₂. A chemical radical reaction between a commercially available peracetic acid (PAA) solution and a potassium iodide (KI) solution was used to produce I₂ and I₃⁻ ions, which combined with a strong basic anion exchange resin to produce TR. The disinfection of pathogenic microorganisms (e.g., Escherichia coli, Salmonella spp.) present in anaerobically digested livestock wastewater is essential prior to its discharge into public water systems or marine environments, in order to safeguard environmental integrity and public health. Anaerobically treated contaminated livestock wastewater was sterilized through three rounds of treatment with a TR column and prepared by the oxidation of a 100 mM KI solution. Full article

(This article belongs to the Topic Sustainable Development of Clean Water and Sanitation)

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16 pages, 3777 KiB

Open AccessArticle

Assessing the Potential of Magnetic Water Treatment of Groundwater for Calcium Carbonate Scale Mitigation in Drinking Water Distribution Networks

by David Sanchez, Eduardo Herrera-Peraza, Carmen Navarro-Gomez and Jesus Ruben Sanchez-Navarro

Water 2025, 17(9), 1265; https://doi.org/10.3390/w17091265 - 24 Apr 2025

Abstract

Mineral scaling and corrosion pose significant challenges in groundwater distribution, increasing hydraulic resistance, reducing flow rates, and raising operational costs. Magnetic water treatment (MWT) has gained attention as a non-chemical method to mitigate scale formation by promoting the transformation of calcite, a hard [...] Read more.

Mineral scaling and corrosion pose significant challenges in groundwater distribution, increasing hydraulic resistance, reducing flow rates, and raising operational costs. Magnetic water treatment (MWT) has gained attention as a non-chemical method to mitigate scale formation by promoting the transformation of calcite, a hard and adherent CaCO₃ polymorph, into aragonite, a softer and less adherent form. In Chihuahua, Mexico, mineral scaling has disrupted the drinking water distribution system, reducing flow and impairing service. This study evaluates MWT’s potential to mitigate scaling by analyzing magnetized water treated under various MWT configurations. Comparative analyses were conducted via XRD and SEM to assess changes in calcium carbonate polymorphs. Finite element method (FEM) simulations in COMSOL Multiphysics 6.0 were used to evaluate the magnetic field distribution. The results show no systematic trend in CaCO₃ polymorph transformation following MWT exposure, and FEM simulations indicate negligible magnetic field gradients in certain configurations. These findings highlight the critical role of optimizing magnetic field alignment and gradient strength. Future research should refine MWT configurations and incorporate real-time monitoring to enhance its effectiveness in scale prevention. Full article

(This article belongs to the Special Issue Groundwater Flow and Transport Modeling in Aquifer Systems)

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14 pages, 3141 KiB

Open AccessArticle

Effects of Salinity Level on Microplastic Removal in Simulated Waters Using Agglomeration–Micro-Flotation

by Theerayut Phengsaart, Palot Srichonphaisarn, Worada Khwathichak, Chanatip Bumrungsak, Ilhwan Park, Mayumi Ito, Mylah Villacorte-Tabelin, Carlito Baltazar Tabelin, Sanghee Jeon, Kazutoshi Haga and Onchanok Juntarasakul

Water 2025, 17(9), 1264; https://doi.org/10.3390/w17091264 - 23 Apr 2025

Abstract

This study investigates the removal of microplastics (MPs) from simulated freshwater, brackish water, and seawater using a novel agglomeration–micro-flotation technique. This method combines particle size enlargement, facilitated by kerosene as a bridging agent, with bubble size reduction through column flotation to enhance the [...] Read more.

This study investigates the removal of microplastics (MPs) from simulated freshwater, brackish water, and seawater using a novel agglomeration–micro-flotation technique. This method combines particle size enlargement, facilitated by kerosene as a bridging agent, with bubble size reduction through column flotation to enhance the removal rate. Six common MP types—polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polystyrene (PS), polyethylene terephthalate (PET), and polyvinyl chloride (PVC)—were evaluated under varying salinity levels and kerosene dosages. Results showed that increasing kerosene dosage significantly improved removal rates, achieving up to ~99% recovery at 10 µL for low- and medium-density MPs (PP, PE, ABS, and PS), while a higher dosage of 30 µL was required for high-density MPs (PET and PVC). Elevated salinity levels (50–100%) promoted bubble stabilization and reduced coalescence, enhancing particle–bubble collisions and the overall flotation performance. This work addresses a key research gap in flotation-based MP removal under saline conditions and highlights the dual benefits of using kerosene—not only to enhance the removal rate but also to enable energy recovery, as both kerosene and plastics are combustible. The proposed technique presents a promising approach for microplastic remediation in aquatic environments, supporting sustainable water treatment and circular resource utilization. Full article

(This article belongs to the Special Issue Trends in Effective Removal of Emerging Organic Pollutants from Drinking Water and Wastewater)

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20 pages, 8397 KiB

Open AccessArticle

Advancing Sea Ice Thickness Hindcast with Deep Learning: A WGAN-LSTM Approach

by Bingyan Gao, Yang Liu, Peng Lu, Lei Wang and Hui Liao

Water 2025, 17(9), 1263; https://doi.org/10.3390/w17091263 - 23 Apr 2025

Abstract

The thickness of the Arctic sea ice constitutes one of the crucial indicators of global climate change, and while deep learning has shown promise in predicting sea ice thickness (SIT), the field continues to grapple with the challenge of limited data availability. In [...] Read more.

The thickness of the Arctic sea ice constitutes one of the crucial indicators of global climate change, and while deep learning has shown promise in predicting sea ice thickness (SIT), the field continues to grapple with the challenge of limited data availability. In this study, we introduce a Wasserstein Generative Adversarial Network–Long Short-Term Memory (WGAN-LSTM) model, which leverages the data generation capabilities of WGAN and the temporal prediction strengths of LSTM to perform single-step SIT prediction. During model training, the mean square error (MSE) and a novel comprehensive index, the Distance between Indices of Simulation and Observation (DISO), are used as two metrics of the loss function to compare. To thoroughly assess the model’s performance, we integrate the WGAN-LSTM model with the Monte Carlo (MC) dropout uncertainty estimation method, thereby validating the model’s enhanced generalization capabilities. Experimental results demonstrate that the WGAN-LSTM model, utilizing MSE and DISO as loss functions, improves comprehensive performance by 51.9% and 75.2%, respectively, compared to the traditional LSTM model. Furthermore, the MC estimates of the WGAN-LSTM model align with the distribution of actual observations. These findings indicate that the WGAN-LSTM model effectively captures nonlinear changes and surpasses the traditional LSTM model in prediction accuracy. The demonstrated effectiveness and reliability of the WGAN-LSTM model significantly advance short-term SIT prediction research in the Arctic region, particularly under conditions of data scarcity. Additionally, this model offers an innovative approach for identifying other physical features in the sea ice field based on sparse data. Full article

(This article belongs to the Special Issue Mathematical, Physical, Chemical, and Biological Methods for Ice and Water Problems)

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17 pages, 9958 KiB

Open AccessArticle

Intermittent Rainfed Rice var. INIA 516 LM1: A Sustainable Alternative for the Huallaga River Basin

by Ricardo Flores-Marquez, Rita de Cássia Bahia, Yuri Arévalo-Aranda, Edson Esmith Torres-Chávez, Jonathan Guevara, Abner Antezana, Antoni Carranza, Ceila Lao and Richard Solórzano-Acosta

Water 2025, 17(9), 1262; https://doi.org/10.3390/w17091262 - 23 Apr 2025

Abstract

Climate change is projected to increase global temperatures and alter rainfall patterns. In Peru, these changes could adversely affect the central basin of the Huallaga River by increasing pest and disease incidence, evapotranspiration, and water consumption. This basin is one of the country’s [...] Read more.

Climate change is projected to increase global temperatures and alter rainfall patterns. In Peru, these changes could adversely affect the central basin of the Huallaga River by increasing pest and disease incidence, evapotranspiration, and water consumption. This basin is one of the country’s main rice-producing regions, where the crop is traditionally cultivated using inefficient practices, such as continuous flood irrigation. This study evaluated the effects of different irrigation management strategies on the growth and yield of rice (Oryza sativa var. INIA 516 LM1-La Unión 23), the water footprint as an indicator of water use efficiency, and the incidence of pests and diseases associated with irrigation regimes. Three irrigation treatments were implemented: Traditional flooding T1 (maintenance of a 0.15 m water layer with replenishment every 4 days), Optimized flooding T2 (replenishment every 7 days), and Intermittent rainfed irrigation T3 (replenishment every 14 days). Although no significant differences were observed in biometric parameters, yield, or pest and disease incidence, a trend of decreasing yield with longer irrigation intervals was noted: traditional flooding (7.91 t∙ha⁻¹) > reduced flooding (7.82 t∙ha⁻¹) > intermittent rainfed (7.14 t∙ha⁻¹). The incidence of white leaf virus and Burkholderia glumae was highest in the intermittent rainfed treatment, followed by optimized flooding, with the lowest incidence in traditional flooding. Yield reduction and the use of rainwater to cover water requirements resulted in a lower total water footprint for traditional flooding (834.0 m³∙t⁻¹), followed by optimized flooding (843.6 m³∙t⁻¹) and intermittent rainfed (923.9 m³∙t⁻¹). This reflects an improvement in rainwater use efficiency. The findings suggest intermittent rainfed irrigation enhances water use efficiency without significantly compromising rice yield or increasing disease incidence in rice var. INIA 516 LM1-La Unión 23 in the central basin of the Huallaga River. Full article

(This article belongs to the Special Issue Methods and Tools for Sustainable Agricultural Water Management)

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18 pages, 5098 KiB

Open AccessArticle

Waterway Regulation Effects on River Hydrodynamics and Hydrological Regimes: A Numerical Investigation

by Chuanjie Quan, Dasheng Wang, Xian Li, Zhenxing Yao, Panpan Guo, Chen Jiang, Haodong Xing, Jianyang Ren, Fang Tong and Yixian Wang

Water 2025, 17(9), 1261; https://doi.org/10.3390/w17091261 - 23 Apr 2025

Abstract

As a critical intervention for enhancing inland navigation efficiency, waterway regulation projects profoundly modify riverine hydrodynamic conditions while optimizing navigability. This study employs the MIKE21 hydrodynamic model to establish a two-dimensional numerical framework for assessing hydrological alterations induced by channel regulation in the [...] Read more.

As a critical intervention for enhancing inland navigation efficiency, waterway regulation projects profoundly modify riverine hydrodynamic conditions while optimizing navigability. This study employs the MIKE21 hydrodynamic model to establish a two-dimensional numerical framework for assessing hydrological alterations induced by channel regulation in the Hui River, China. Through comparative simulations of pre- and post-project scenarios across dry, normal, and wet hydrological years, the research quantifies impacts on water levels, flow velocity distribution, and geomorphic stability. Results reveal that channel dredging and realignment reduced upstream water levels by up to 0.26 m during drought conditions, while concentrating flow velocities in the main channel by 0.5 m/s. However, localized hydrodynamic restructuring triggered bank erosion risks at cut-off bends and sedimentation in anchorage basins. The integrated analysis demonstrates that although regulation measures enhance flood conveyance and navigation capacity, they disrupt sediment transport equilibrium, destabilize riparian ecosystems, and compromise hydrological monitoring consistency. To mitigate these trade-offs, the study proposes design optimizations—including ecological revetments and adaptive dredging strategies—coupled with enhanced hydrodynamic monitoring and riparian habitat restoration. These findings provide a scientific foundation for balancing navigation improvements with the sustainable management of fluvial systems. Full article

(This article belongs to the Special Issue Advances in Surface Water and Groundwater Simulation in River Basin)

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23 pages, 6374 KiB

Open AccessArticle

Evaluating Wildfire-Induced Changes in a Water-Yield Ecosystem Service at the Local Scale Using the InVEST Model

by Ye Inn Kim, Bernie Engel, Won Seok Jang and Young Jo Yun

Water 2025, 17(9), 1260; https://doi.org/10.3390/w17091260 - 23 Apr 2025

Abstract

This study evaluates the applicability of the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) model for assessing wildfire-induced changes in water-related ecosystem services at a localized scale. Wildfires significantly alter hydrological processes by reducing vegetation cover, which in turn affects water-yield dynamics. [...] Read more.

This study evaluates the applicability of the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) model for assessing wildfire-induced changes in water-related ecosystem services at a localized scale. Wildfires significantly alter hydrological processes by reducing vegetation cover, which in turn affects water-yield dynamics. To quantify these changes, we applied the InVEST annual water-yield model to a 4.95 km² wildfire-affected area and validated its outputs against the physically based SWAT model. The study utilized Sentinel-2 imagery to create pre- and post-wildfire land cover maps, which served as key inputs for the InVEST model. The results showed a 7.05% increase in water yield after the wildfire. Validation using SWAT confirmed that InVEST could capture localized hydrological changes with accuracy. While InVEST simplifies hydrological processes by relying primarily on land cover data, it remains a valuable tool for rapid and low-resource assessments in wildfire-prone regions. This study highlights the potential of InVEST for rapid post-fire evaluations, offering a practical decision-support model for post-fire land and water resource management in the context of climate change. Full article

(This article belongs to the Special Issue Application of Various Hydrological Modeling Techniques and Methods in River Basin Management, 2nd Edition)

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16 pages, 4814 KiB

Open AccessArticle

Geomorphological Characteristics and Evolutionary Process of a Typical Isolated Carbonate Platform Slope in the Xisha Sea: A Case Study of the Northwestern Dongdao Platform

by Xudong Guo, Dongyu Lu, Xuelin Li, Xiaochen Fang, Fei Tian, Changfa Xia, Lei Huang, Mei Chen, Luyi Wang and Zhongyu Sun

Water 2025, 17(9), 1259; https://doi.org/10.3390/w17091259 - 23 Apr 2025

Abstract

The northwestern slope of the Dongdao Platform in the Xisha Sea exhibits a complex geomorphological structure. Utilizing high-resolution multibeam bathymetric data and 2D seismic profiles, this study systematically reconstructs the slope morphology and its evolutionary processes. The study area displays a distinct threefold [...] Read more.

The northwestern slope of the Dongdao Platform in the Xisha Sea exhibits a complex geomorphological structure. Utilizing high-resolution multibeam bathymetric data and 2D seismic profiles, this study systematically reconstructs the slope morphology and its evolutionary processes. The study area displays a distinct threefold zonation: the upper slope (160–700 m water depth) has a steep gradient of 15°–25°, characterized by deeply incised V-shaped channels and slump deposits, primarily shaped by gravity-driven erosion; the middle slope (700–1200 m water depth) features a gentler gradient of 10°–15°, where channels stabilize, adopting U-shaped cross-sections with the development of lateral accretion deposits; the lower slope (1200–1500 m water depth) exhibits a milder gradient of 5°–10°, dominated by a mixture of fine-grained carbonate sediments and hemipelagic mud–marine sediments originating partly from the open ocean and partly from the nearby continental margin. The slope extends from 160 m to 1500 m water depth, hosting the C1–C4 channel system. Seismic facies analysis reveals mass-transport deposits, channel-fill facies, and facies modified by bottom currents—currents near the seafloor that redistribute sediments laterally—highlighting the interplay between fluid activity and gravity-driven processes. The slope evolution follows a four-stage model: (1) the pockmark formation stage, where overpressured gas migrates vertically through chimneys, inducing localized sediment instability and forming discrete pockmarks; (2) the initial channel development stage, during which gravity flows exploit the pockmark chains as preferential erosional pathways, establishing nascent incised channels; (3) the channel expansion and maturation stage, marked by intensified erosion from high-density debris flows, resulting in a stepped longitudinal profile, while bottom-current reworking enhances lateral sediment differentiation; (4) the stable transport stage, wherein the channels fully integrate with the Sansha Canyon, forming a well-connected “platform-to-canyon” sediment transport system. Full article

(This article belongs to the Special Issue Regional Geomorphological Characteristics and Sedimentary Processes)

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22 pages, 6999 KiB

Open AccessArticle

Contrasting the Contributions of Climate Change and Greening to Hydrological Processes in Humid Karst and Non-Karst Areas

by Xiaoyu Tan, Yan Deng, Yehao Wang, Linyan Pan, Yuanyuan Chen and Junjie Cai

Water 2025, 17(9), 1258; https://doi.org/10.3390/w17091258 - 23 Apr 2025

Abstract

A quantitative assessment of the responses of hydrological processes to environmental change is vital for the sustainable utilization of groundwater and sustainable development under the dual influences of climate change and global greening. However, few studies have investigated the differences in hydrologic responses [...] Read more.

A quantitative assessment of the responses of hydrological processes to environmental change is vital for the sustainable utilization of groundwater and sustainable development under the dual influences of climate change and global greening. However, few studies have investigated the differences in hydrologic responses between karst and non-karst regions. Thus, we analyzed the spatiotemporal changes in potential groundwater recharge (PGR), potential groundwater recharge as a proportion of precipitation (PGR/P), and actual evapotranspiration (AET) in karst and non-karst regions for 1982–2020 using the V2karst model. The analysis revealed the following results: (1) The V2karst model efficiently monitored variations in the AET and groundwater depth (GWD), which indicated its suitability for use in karst areas. (2) The PGR, PGR/P, and AET increased at rates of 4.9 mm/y, 0.0011, and 1.4 mm/y in karst areas, and 3.8 mm/y, 0.00053, and 1.6 mm/y in non-karst areas, respectively, with the increasing trend in AET being significant in karst and non-karst regions. (3) The precipitation (P) and AET were significantly correlated with the PGR and PGR/P, while the minimum temperature (TMN) was strongly related to the AET. The Normalized Difference Vegetation Index (NDVI) moderately affected the PGR, PGR/P, and AET changes in humid catchments. Climate change is a primary factor for hydrological processes, whereas vegetation restoration has a relatively minor impact. The results of this study are beneficial toward the adoption of strategic groundwater utilization programs and ecological restoration measures for regions with a diverse geological setting. Full article

(This article belongs to the Section Hydrology)

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6 pages, 561 KiB

Open AccessEditorial

Contaminants in the Water Environment: Significance from the Perspective of the Global Environment and Health

by Xia Jiang, Kelly L. Kirsten and Abdul Qadeer

Water 2025, 17(9), 1257; https://doi.org/10.3390/w17091257 - 23 Apr 2025

Abstract

Water is essential for all life, yet it faces increasing threats from contamination due to various human activities and natural processes [...] Full article

(This article belongs to the Special Issue Contaminants in the Water Environment)

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20 pages, 3831 KiB

Open AccessArticle

A Highly Effective Method for Simultaneous Determination of 103 Veterinary Drugs in Sediment Using Liquid Chromatography–Tandem Mass Spectrometry

by Henan Li, Kunde Lin, Yuncong Ge, Qian Wang and Meng Chen

Water 2025, 17(9), 1256; https://doi.org/10.3390/w17091256 - 23 Apr 2025

Abstract

Hundreds of veterinary drugs are widely used in agricultural activities and continuously enter aquatic environments through various pathways, posing potential risks to ecosystem. Considering that sediments function both as sinks and sources of these contaminants, it is crucial to promptly and accurately acquire [...] Read more.

Hundreds of veterinary drugs are widely used in agricultural activities and continuously enter aquatic environments through various pathways, posing potential risks to ecosystem. Considering that sediments function both as sinks and sources of these contaminants, it is crucial to promptly and accurately acquire veterinary drug residue level in sediments. In this study, a highly effective analytical method for simultaneous determination of 103 veterinary drugs from 16 classes in sediments was developed using high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS). The extraction procedure was performed twice by ultrasound-assisted extraction with an acetonitrile-buffer mixture consisting of Na₂EDTA, Na₃PO₄·12H₂O, and Na₃C₆H₅O₇·2H₂O. The supernatant was cleaned using 500 mg/6 mL Oasis HLB solid-phase cartridges. The elution solutions were concentrated and redissolved in formic acid–methanol–water (0.1/20/79.9, v/v, FA-MeOH-H₂O) for detection. Results showed that all 103 target drugs exhibited good linearity with R² > 0.990 over a concentration range of 0.010 to 1000 μg·L⁻¹, and method detection limits (MDLs) ranged from 0.025 to 5 μg·kg⁻¹. The recoveries at three spiking levels (2, 5, and 10 times of the method quantification limits, MQLs) varied from 33% to 150%, 32% to 140%, and 40% to 140%, respectively, with relative standard deviations (RSDs, n = 3) of 0.7%~29%, 0.8%~23%, and 0.5%~20%. The matrix effects for all compounds ranged from –85% to 84% with 32 targets negligible, 51 moderate, and 20 significant. An isotope-labeled surrogate method was proposed for quantitation to effectively overcome matrix effects and improve accuracy with better recoveries of 60%~120% for 93 target drugs and RSDs (n = 3) all below 20%. This method was applied to determine 12 sediment samples collected from the Jiulong River, and 16 target drugs were detected in the concentrations range of 0.1~7.6 μg·kg⁻¹. The method is accurate, sensitive, and efficient, providing a powerful analytical tool for behavior and effect studies of multi-classed veterinary drug residue in sediment environments. Full article

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

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