Water

14 pages, 3304 KB

Open AccessArticle

Influence of Blade Tip Clearance on External Characteristics and Internal Flow Pattern of Axial Flow Pumps

by Ling Bai, Jie Zhang, Lei Jiang, Hong Xu and Ling Zhou

Water 2026, 18(3), 437; https://doi.org/10.3390/w18030437 - 6 Feb 2026

Axial flow pumps, widely utilized in critical fields such as agricultural irrigation, urban water diversion and flood control, play an indispensable role in large-scale water transport and drainage projects due to their high-flow and low-head characteristics. This study systematically investigates the influence of [...] Read more.

Axial flow pumps, widely utilized in critical fields such as agricultural irrigation, urban water diversion and flood control, play an indispensable role in large-scale water transport and drainage projects due to their high-flow and low-head characteristics. This study systematically investigates the influence of tip clearance on the external characteristics and internal flow field of a large-scale axial flow pump (model 1800GZX-125). By combining numerical simulations with experimental validation, a comparative analysis was conducted under four tip clearance sizes (3 mm, 12 mm, 17.5 mm, 24 mm) and various flow conditions. The results indicate that increasing the tip clearance generally reduces the pump head and peak efficiency. It also alters the blade pressure distribution, expands the low-pressure region, and intensifies tip leakage flow. While vorticity overall increases, it weakens locally under certain conditions due to changes in leakage flow patterns. Entropy generation analysis further reveals that larger clearances lead to significantly increased energy losses, thereby degrading external performance. These findings provide a theoretical basis for improving the performance and operational stability of axial flow pumps. Full article

(This article belongs to the Special Issue Hydrodynamics in Pumping and Hydropower Systems, 2nd Edition)

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21 pages, 4464 KB

Open AccessArticle

Future Climate Change Increases Streamflow and Risks of Hydrological Hazards in the Pearl River Basin

by Haoyuan Yu, Qichun Yang, Liuqian Yu, Xia Li, Minyang Li and Yingxian Yang

Water 2026, 18(3), 436; https://doi.org/10.3390/w18030436 - 6 Feb 2026

Abstract

Understanding and predicting climate change impacts on the terrestrial water cycle is essential for water resources management and hazard prevention. This study aims to project future runoff of a densely-populated river basin, the Pearl River Basin (PRB), under different Shared Socioeconomic Pahway (SSP) [...] Read more.

Understanding and predicting climate change impacts on the terrestrial water cycle is essential for water resources management and hazard prevention. This study aims to project future runoff of a densely-populated river basin, the Pearl River Basin (PRB), under different Shared Socioeconomic Pahway (SSP) scenarios, by combining the Soil and Water Assessment Tool (SWAT) model and the CMIP6 climate projections. Results show that climate change will significantly increase the runoff of the PRB, with changing rates of 0.21, 0.20, 0.11, and 0.17 mm/month/year for low- to high-emission scenarios SSP126, SSP245, SSP370, and SSP585, respectively. Future runoff exhibits strong seasonal and spatial variability due to complex changes in precipitation and potential evapotranspiration across the basin. The PRB may experience higher flood risks during the wet season under all SSP scenarios, driven by a ~15% increase in runoff during the wettest month during 2061–2100 relative to that of 2021–2060. Conversely, drought risks may escalate in the East River Sub-basin of the PRB during the dry season under the high-emission scenarios (SSP370 and SSP585), with a ~20% reduction in runoff during the driest month during 2061–2100 relative to that of 2021–2060. The highest-emission scenario (SSP585) may lead to the most drastic hydrological changes, including increased risks of flooding and drought across different parts of the PRB. Our findings suggest intensified water cycling and increased hydrological risks in the PRB under a changing climate, highlighting the necessity of future water resource management to consider potential climate change impacts to mitigate the risks of floods and droughts effectively. Full article

(This article belongs to the Special Issue Using Hydrological Modeling for Spatio-Temporal Analysis of Rainfall Signatures)

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12 pages, 1821 KB

Open AccessArticle

Impact of Food Processing Industry Wastewater on Root Growth and DNA Damage in Allium cepa L. as Assessed by the Comet Assay

by Matiba Tufail, Muhammad Luqman, Zahid Mehmood, Wasim Abbas, Maryam Iqbal, Harma Shah, Imran Farooq Awan, Noor Sana, Arooba John, Samra Rafiq, Awais Riaz, Adeel Ahmad, Anum Tahir and Muhammad Umar Farooq Awan

Water 2026, 18(3), 435; https://doi.org/10.3390/w18030435 - 6 Feb 2026

Abstract

Wastewater from food processing industries contains synthetic dyes and preservatives that may pose phytotoxic and genotoxic risks. The present work represents an exploratory study based on a wastewater source and sampling period. Wastewater was characterized by physicochemical analysis and high-performance liquid chromatography (HPLC). [...] Read more.

Wastewater from food processing industries contains synthetic dyes and preservatives that may pose phytotoxic and genotoxic risks. The present work represents an exploratory study based on a wastewater source and sampling period. Wastewater was characterized by physicochemical analysis and high-performance liquid chromatography (HPLC). Onion seeds and bulbs were exposed to 0% (control), 20%, 40%, 60%, 80%, and 100% wastewater dilution. DNA was extracted from root cells using the cetyltrimethylammonium bromide (CTAB) method. The DNA damage was analyzed by the comet assay. HPLC analysis confirmed the presence of sorbic acid, citric acid, benzoic acid, butylated hydroxyanisole (BHA), and butylated Hydroxytoluene (BHT) by showing corresponding peaks. The mean root length in wastewater was significantly reduced by 55%, 50%, and 65% on days 3, 5, and 7, respectively, relative to the control. On day 3, the highest genotoxicity at 100% wastewater was indicated by 96.69% tail DNA, a tail moment of 108.3 a.u., an Olive tail moment of 58.01 a.u., and a comet length of 136 µm. Enhanced DNA damage persisted on days 5 and 7, with comet lengths reaching 127–149 µm and 111–182 µm, respectively. Although the observed effects may reflect general cytotoxicity arising from a complex wastewater mixture and showed that untreated food processing wastewater presents a significant genotoxic risk and requires effective treatment prior to reuse. Full article

(This article belongs to the Special Issue Advances and Innovations in Technologies for Treatment and Toxicity Assessment of Conventional and Emerging Contaminant in Industrial Wastewater)

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19 pages, 970 KB

Open AccessArticle

Constraint-Aware and Economic Optimization of Riverbank Retaining Walls Using Metaheuristic Algorithms

by Shaymaa Alsamia, Edina Koch and Mais Mayassah

Water 2026, 18(3), 434; https://doi.org/10.3390/w18030434 - 6 Feb 2026

Abstract

The optimal design of riverbank retaining walls requires a careful balance between structural safety, constructability, and economic efficiency. In this study, a constraint-aware optimization framework is developed for the design of concrete gravity retaining walls by explicitly incorporating stability, serviceability, and geometric feasibility [...] Read more.

The optimal design of riverbank retaining walls requires a careful balance between structural safety, constructability, and economic efficiency. In this study, a constraint-aware optimization framework is developed for the design of concrete gravity retaining walls by explicitly incorporating stability, serviceability, and geometric feasibility constraints. Several metaheuristic algorithms are comparatively evaluated under identical computational conditions using 30 independent runs, a population size of 50, and 1000 iterations. The results demonstrate that enforcing geometric constraints is essential to prevent non-physical designs and to ensure engineering realism. Quantitative analysis shows that the Flower Fertilization Optimization (FFO) algorithm yields the minimum wall weight, reducing material usage by approximately 19% compared to more conservative solutions. In contrast, the adaptive exploration artificial bee colony (AEABC) algorithm exhibits the most robust and repeatable convergence behavior with low statistical dispersion across independent runs. An economic assessment based on concrete volume further confirms the direct impact of material efficiency on construction cost. The proposed framework highlights the importance of constraint-aware optimization for achieving reliable and economically efficient retaining wall designs. Full article

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

20 pages, 1239 KB

Open AccessArticle

Sustainable Selection Criteria for Small Wastewater Treatment Plants Ensuring Biodegradation

by Zbigniew Mucha, Agnieszka Generowicz, Kamil Zieliński, Iga Pietrucha, Anna Kochanek, Piotr Herbut, Paweł Kwaśnicki, Anna Gronba-Chyła and Elżbieta Sobiecka

Water 2026, 18(3), 433; https://doi.org/10.3390/w18030433 - 6 Feb 2026

Abstract

The rapid development of rural and peri-urban areas increases the demand for decentralized wastewater treatment systems. Small wastewater treatment plants (SWTPs) with a capacity below 2000 PE are becoming an important element of local water protection and circular-economy strategies, yet clear guidelines for [...] Read more.

The rapid development of rural and peri-urban areas increases the demand for decentralized wastewater treatment systems. Small wastewater treatment plants (SWTPs) with a capacity below 2000 PE are becoming an important element of local water protection and circular-economy strategies, yet clear guidelines for selecting appropriate technologies are still lacking. This study analyzes the criteria used in decision-making for SWTPs from a multi-stakeholder perspective and evaluates the relative importance of technical, economic, environmental and social factors. The research was conducted in Poland and included a survey of 130 respondents representing six stakeholder groups (officials, operators, designers, contractors, scientists and residents). Respondents allocated weights to four main groups of criteria and assessed eleven detailed parameters on a 1–10 scale. The data were analyzed using descriptive statistics, the Kolmogorov–Smirnov test with the Lilliefors correction to verify distribution assumptions, and the Kruskal–Wallis test to examine differences between stakeholder groups. The results show a consistent hierarchy of criteria, with technical reliability, treatment efficiency and operating costs ranked as the most important factors. Social and environmental aspects were assessed as relevant but secondary. Only minor differences between stakeholder groups were observed. The study highlights the need for integrated, multicriteria approaches in SWTP planning, particularly in dispersed rural areas. The findings may support local authorities, designers and investors in technology selection. The research is limited by the non-probability sampling strategy, the national scope of the dataset and the cross-sectional character of the survey. Full article

(This article belongs to the Special Issue Sustainable Biodegradation and Bioremediation of Organic Contaminants in Aquatic and Terrestrial Environments)

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19 pages, 38597 KB

Open AccessArticle

Hydraulic Characteristics and the Adaptability to Water-Level Fluctuation of the Vertical-Slot Fishway

by Xianglong Huang, Junjun Tan, Yuanyang Wang, Junjian Sun, Sicheng Zeng, Shuaijie Wu and Xiaotao Shi

Water 2026, 18(3), 432; https://doi.org/10.3390/w18030432 - 6 Feb 2026

Abstract

This study explored the hydraulic characteristics and the adaptability to water-level fluctuations of the vertical-slot fishway. The maximum allowable water depth difference between the entrance and exit was calculated for a one-entrance fishway and two-entrance fishways with different entrance distances (100 m, 200 [...] Read more.

This study explored the hydraulic characteristics and the adaptability to water-level fluctuations of the vertical-slot fishway. The maximum allowable water depth difference between the entrance and exit was calculated for a one-entrance fishway and two-entrance fishways with different entrance distances (100 m, 200 m, 300 m) under insufficient entrance water depth, with a fishway slope of 2% and an exit water depth of 2.5 m. It was found that the maximum allowable water depth difference between the 1# entrance and exit of the two-entrance fishways (0.71 m, 0.85 m, 0.93 m) was greatly larger than that of the one-entrance fishway (0.48 m). Additionally, the maximum allowable water depth difference in the two-entrance fishway increased with the increased distance between the two entrances. The relationship between the maximum allowable water depth difference and the distance of the two entrances followed a logarithmic function. We suggested that the 2# entrance should be at least 1.6 m when the water depth of 1# entrance was decreased to 1.8 m. When the water depth of the 1# entrance was gradually decreased to 1.6 m, the water depth of the 2# entrance also gradually decreased to 1.2 m. The distance between the 1# entrance and 2# entrance subsequently changed. It was noteworthy that the conclusions proposed in this study were strictly limited to vertical-slot fishways with a slope of 2%, exit water depth of 2.5 m, similar geometric parameters, and target cyprinid species. Furthermore, different slopes or exit water depths should be studied to extend the relationship by introducing correction coefficients from subsequent studies. This study can provide references for the design and optimization of future fishway projects. Full article

(This article belongs to the Special Issue Ecohydraulics and Fish Behavior Simulation)

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14 pages, 2037 KB

Open AccessArticle

Turbulence in a Bend in the Presence of Emergent Vegetation and a 3D Pool Bedform

by Alirahm Rahimpour, Hossein Afzalimehr, Saeid Okhravi, Mohammad Nazari-Sharabian and Moses Karakouzian

Water 2026, 18(3), 431; https://doi.org/10.3390/w18030431 - 6 Feb 2026

Abstract

The interaction of emergent vegetation and three-dimensional (3D) bedforms is essential for understanding turbulent flow dynamics in curved channels. A laboratory investigation can help to collect required data under controlled conditions. Experiments were conducted in a 9.5 m-long, 0.9 m-wide recirculating flume incorporating [...] Read more.

The interaction of emergent vegetation and three-dimensional (3D) bedforms is essential for understanding turbulent flow dynamics in curved channels. A laboratory investigation can help to collect required data under controlled conditions. Experiments were conducted in a 9.5 m-long, 0.9 m-wide recirculating flume incorporating a 90° bend and a sculpted 3D pool bedform. Artificial rigid vegetation, designed to replicate the hydraulic behavior of natural emergent plants, was installed along both sidewalls. Instantaneous three-dimensional velocities were recorded using an acoustic Doppler velocimeter (ADV) across multiple cross-sections under both bare-bed and vegetated conditions. The results reveal that emergent vegetation markedly increases flow resistance, distorts mean velocity distributions, and suppresses the classical logarithmic velocity profile, particularly within the bend and pool regions. The combined presence of vegetation and the 3D pool bedform amplified turbulence intensity, elevated Reynolds shear stresses, and redistributed turbulent kinetic energy (TKE), which increased by up to sevenfold from the bend entrance to its exit. In vegetated pool sections, Reynolds stresses were approximately 12% greater than under bare-bed conditions, underscoring the synergistic effects of vegetation drag, secondary circulation, and flow separation in producing anisotropic turbulence. These findings highlight the importance of incorporating vegetation–bedform interactions in fluvial modeling frameworks, with significant implications for sediment transport prediction, channel stability evaluation, river restoration, and aquatic habitat design. Full article

(This article belongs to the Special Issue Advancing Hydro-Environmental Research and Practice: Integrating Ecohydrology, Remote Sensing and Hydroinformatics)

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21 pages, 2167 KB

Open AccessArticle

Understanding Spatiotemporal Inundation Dynamics in the Sundarbans Mangroves Through Hydrodynamic Modelling

by Fazlul Karim, Shaikh Nahiduzzaman, Raju Ahmmad, Mohammed Mainuddin, Shahriar Wahid and Rubayat Alam

Water 2026, 18(3), 430; https://doi.org/10.3390/w18030430 - 6 Feb 2026

Abstract

Tidal inundation plays a critical role in maintaining the ecosystem services of the Sundarbans mangrove forest. In this study, we configured and calibrated a coupled one-dimensional (1D) river network and two-dimensional (2D) floodplain hydrodynamic model for the Sundarbans in Bangladesh. Model calibration was [...] Read more.

Tidal inundation plays a critical role in maintaining the ecosystem services of the Sundarbans mangrove forest. In this study, we configured and calibrated a coupled one-dimensional (1D) river network and two-dimensional (2D) floodplain hydrodynamic model for the Sundarbans in Bangladesh. Model calibration was performed using gauged water levels, inundation maps, and Google Earth (Version 7.3.6) imagery. Using the calibrated model, we assessed potential changes in inundation extent, depth, and duration across the Sundarbans for varying freshwater inflow and tidal height scenarios. Results show variation in inundation extent, depth, and duration spatially and temporarily across the Sundarbans. Inundation is relatively less during February-March (end of the dry season) and high in July-August (mid-wet season). Approximately 3158 km² (85.1%) of the Sundarbans experiences at least one inundation in March, increasing to about 3658 km² (98.6%) in July. Although a large proportion of the Sundarbans inundate during daily tidal cycles, the mean inundation depth remains shallow (0.24 to 0.33 m) due to flat topography. The influence of freshwater inflow on inundations is small (<2%). In contrast, the impacts of tidal magnitude are substantial on both inundation extent and depth. These findings provide valuable insights on inundation dynamics for understanding the hydrological and ecological functioning of the Sundarbans. Full article

(This article belongs to the Special Issue Flood Inundation Modeling and Mapping: Application of Hydrodynamic Models, Remote Sensing and Machine Learning Tools)

20 pages, 4107 KB

Open AccessArticle

Analysis of Contaminant Behavior in Loop Pipe System for Ultrapure Water Distribution Using Computational Fluid Dynamics and Autopsy

by Juyoung Andrea Lee, Jinsu Park, Song Lee, Kyunghyun Son and Sangho Lee

Water 2026, 18(3), 429; https://doi.org/10.3390/w18030429 - 6 Feb 2026

Abstract

Ultrapure water (UPW) distribution loops must deliver stable hydraulics while limiting contamination from polymer piping. This study integrates computational fluid dynamics (CFD) with systematic pipe autopsy to examine contaminant behavior in a pilot-scale UPW loop constructed using chlorinated polyvinyl chloride (CPVC) and polyvinylidene [...] Read more.

Ultrapure water (UPW) distribution loops must deliver stable hydraulics while limiting contamination from polymer piping. This study integrates computational fluid dynamics (CFD) with systematic pipe autopsy to examine contaminant behavior in a pilot-scale UPW loop constructed using chlorinated polyvinyl chloride (CPVC) and polyvinylidene fluoride (PVDF) and operated under identical conditions. CFD predicted nearly identical loop-scale velocity, pressure, and temperature fields for both materials, and identified low-shear recirculation at elbows and downstream tees as zones of elevated particle residence. Lagrangian particle tracking (0.05 μm, no-sticking) showed rapid breakthrough and complete flushing within 13 min, providing a hydraulic susceptibility map for transient retention. After eight months of operation, 17 sections were inspected endoscopically and leached at 60 °C. CPVC exhibited yellow–brown discoloration and highly heterogeneous total organic carbon (TOC) release with hot spots of 16–18 mg·L⁻¹, whereas PVDF showed low, spatially uniform TOC (0.4–2.3 mg·L⁻¹) and minimal fouling; inorganic ions remained at sub-mg·L⁻¹ levels for both materials. Overall, geometry governs where contamination can accumulate, while material properties control its magnitude and persistence, with PVDF providing greater resistance to long-term organic contamination than CPVC. Full article

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

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5 pages, 151 KB

Open AccessEditorial

Integrated Approaches to Water Resources and Environmental Management: Innovations in Simulation and Impact Assessment

by Yuntao Wang

Water 2026, 18(3), 428; https://doi.org/10.3390/w18030428 - 6 Feb 2026

Abstract

Water resources and environmental systems face unprecedented pressure from the combined effects of climate change, rapid urbanization, population growth, land-use transformation, and intensifying economic activities [...] Full article

(This article belongs to the Special Issue Integrated Approaches to Water Resources and Environmental Management: Innovations in Simulation and Impact Assessment)

19 pages, 4029 KB

Open AccessArticle

Smart Technological Urban Flood Management Strategies Are “Must-Do” Approaches: The Case of Chinese Coastal Megacity, Ningbo, East Coast of China

by Faith Ka Shun Chan, Weiwei Gu, Fang Zhang, Xiaolei Pei, Zilin Wang, Lingwen Lu, Ming Cheng, Yuhe Wang, Weiguo Zhang and Yutian Jiang

Water 2026, 18(3), 427; https://doi.org/10.3390/w18030427 - 6 Feb 2026

Abstract

Ningbo (NGB), a major port city on China’s east coast, is defined by a network of over 100 rivers across three major catchments. From the 1970s to the 2000s, extensive engineering, including channelisation and embankment construction, was used to manage flood risk during [...] Read more.

Ningbo (NGB), a major port city on China’s east coast, is defined by a network of over 100 rivers across three major catchments. From the 1970s to the 2000s, extensive engineering, including channelisation and embankment construction, was used to manage flood risk during rapid urbanisation. Since the 2010s, however, the city has shifted towards smart flood management. The Ningbo government and Water Bureau have deployed digital twins and technologies like 3D flood mapping and real-time monitoring, significantly improving precision. Our study demonstrated that this smart technology performed effectively during recent extreme events, namely typhoons In-Fa (2021) and Muifa (2022), helping the Municipal Bureau to safeguard public safety. This success strengthens municipal and national commitments to climate resilience. Nevertheless, further advancement of the digital twin platform is required. Key priorities include boosting computational capacity, improving cross-departmental coordination, establishing open data sharing, and integrating artificial intelligence (AI) to enhance decision-making during future climate extremes. Full article

(This article belongs to the Special Issue Water Reuse and Land Management: Strategies, Policies, and Integrated Land-Use Approaches)

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13 pages, 925 KB

Open AccessReview

Marine Pollution in Panama: A Bibliometric Approach to Knowledge Gaps and Institutional Influence

by Nelva E. Alvarado-González, Yulissa De Gracia, Jenifer Ortega, Maricselis Díaz, Yostin Añino, Xabier Lekube, Maren Ortiz-Zarragoitia and Beñat Zaldibar

Water 2026, 18(3), 426; https://doi.org/10.3390/w18030426 - 6 Feb 2026

Abstract

Human activities in Panama, such as agriculture, industry, and transport, have led to the release of pollutants that affect the health of marine and coastal ecosystems. However, there is a lack of bibliographic compilation studies to understand the current state of research on [...] Read more.

Human activities in Panama, such as agriculture, industry, and transport, have led to the release of pollutants that affect the health of marine and coastal ecosystems. However, there is a lack of bibliographic compilation studies to understand the current state of research on marine pollution in Panama. In recent years, bibliometric studies have attracted attention due to the development of new analytical and integrative online tools. This study conducts a bibliometric analysis of marine pollution and its environmental effects on Panama’s coastal areas. The results show consistent growth in scientific production, with increased collaboration among researchers. However, the involvement of national institutions is limited, highlighting the need to strengthen local research. Most publications focus on environmental sciences, with a recent shift towards studying a broader range of pollutants. Full article

(This article belongs to the Section Oceans and Coastal Zones)

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Graphical abstract

13 pages, 1250 KB

Open AccessArticle

Tritium and Plutonium Time Series from the Puruogangri Ice Field, Tibetan Plateau, China

by László Palcsu, Miruna Cotan, Lide Tian, Cheng Wang, Liu Feng, Xu Chenhao, Yu Songlin, Magdolna Szilágyi, Loránd Zákány, Zoltán Dezső, Danny Vargas and Marjan Temovski

Water 2026, 18(3), 425; https://doi.org/10.3390/w18030425 - 5 Feb 2026

Abstract

Ice cores retrieved from the Third Pole provide invaluable information about past and present environmental changes. Here we present, for the first time, a continuous tritium and plutonium isotope profile of the Puruogangri ice field, Tibetan Plateau, China, for the last 70 years. [...] Read more.

Ice cores retrieved from the Third Pole provide invaluable information about past and present environmental changes. Here we present, for the first time, a continuous tritium and plutonium isotope profile of the Puruogangri ice field, Tibetan Plateau, China, for the last 70 years. The age-depth profile has been composed by different time anchors such as the onset of thermonuclear weapon tests, the so-called bomb peak of tritium, the Chernobyl event, and the time of ice coring. The accumulation rate of ice calculated from the age-depth relation shows a decrease after 1963. It was 57, 15, and 22 cm/year in the periods of 1954–1963, 1963–1986, and 1986–2023, respectively. The concentrations of plutonium isotopes (²³⁹Pu: up to 2.7 fg/g) are slightly lower than those of the Belukha ice core, Siberian Altai, Russia, and almost the same as the Miaoergou glacier, eastern Tien Shan, China. Contrary to this latter ice core profile, the Puruogangri plutonium profile reflects that the Chinese weapon test started in 1966. This is confirmed by the tritium time series as well. ²⁴⁰Pu/²³⁹Pu atomic ratios vary between 0.14 and 0.23, with an average of 0.177 ± 0.024. The overall obtained local fallout of ²³⁹Pu and ²⁴⁰Pu is 13.2 and 9.0 Bq/m² (4.0 and 1.1 ng/m²), respectively. Full article

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

27 pages, 3345 KB

Open AccessArticle

Distributive Disturbances: Examining Community Exposure to Drinking Water Contaminants Amidst the Jackson, Mississippi (USA) Water Crisis

by Ambria N. McDonald, Yolanda J. McDonald, Andrea Chow, Julia Kosinski and Dorceta E. Taylor

Water 2026, 18(3), 424; https://doi.org/10.3390/w18030424 - 5 Feb 2026

Abstract

Community water systems in the United States provide drinking water to more than 300 million people annually, making their reliability fundamental to public health. In regions with long histories of racial segregation and unequal infrastructure maintenance, water system failures can deepen existing environmental [...] Read more.

Community water systems in the United States provide drinking water to more than 300 million people annually, making their reliability fundamental to public health. In regions with long histories of racial segregation and unequal infrastructure maintenance, water system failures can deepen existing environmental injustices. This study examines water quality conditions in the Jackson, Mississippi, metropolitan area following the 2022 distribution system collapse and a decade of repeated noncompliance with the Safe Drinking Water Act’s Lead and Copper Rule (LCR). Using the U.S. Environmental Protection Agency’s 2024 updated LCR tap sampling protocol, water samples from 29 sites were collected. Samples were analyzed for lead, copper, iron, zinc, chlorine, sulfate, pH, and total dissolved solids concentrations. Chlorine-to-sulfate mass ratios (CSMR) were also calculated to evaluate corrosion potential. Demographic surveys, statistical analyses, and geospatial visualizations were used to interpret neighborhood-level patterns. Our findings show that all sites met primary drinking water standards and complied with LCR action levels but exceeded secondary drinking water standards at 100% of study sites. Seven sites exhibited CSMR values above the threshold, indicating increased susceptibility to corrosion. These results highlight the need for targeted corrosion control, treatment optimization, and ongoing monitoring, particularly in historically marginalized communities. Full article

(This article belongs to the Special Issue Spatial Linkages Between Geographical Environments and Health Indicators: From Water Quality Parameters to Regional Health Status)

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18 pages, 5522 KB

Open AccessArticle

A Study on the Hydrogen and Oxygen Stable Isotope Characteristics of Water in Small Watersheds on the Southern Slope of the Qilian Mountains

by Qixin He, Guangchao Cao, Guangzhao Han, Meiliang Zhao, Jiaqi Bai and Wenqian Ye

Water 2026, 18(3), 423; https://doi.org/10.3390/w18030423 - 5 Feb 2026

Abstract

This study, based on stable hydrogen and oxygen isotope observations of multiple water bodies (precipitation, river water, soil water, and groundwater) in the Ami Dongsou alpine arid watershed on the southern slope of the Qilian Mountains during 2023–2024, reveals significant seasonal fluctuations in [...] Read more.

This study, based on stable hydrogen and oxygen isotope observations of multiple water bodies (precipitation, river water, soil water, and groundwater) in the Ami Dongsou alpine arid watershed on the southern slope of the Qilian Mountains during 2023–2024, reveals significant seasonal fluctuations in water isotope characteristics and water source renewal mechanisms. The results show that precipitation and soil water exhibit notable enrichment during the dry season, primarily due to enhanced evaporation causing light isotopes to evaporate and heavy isotopes to accumulate. River water, influenced by both precipitation recharge and evaporation, shows smaller seasonal fluctuations. Groundwater isotopes remain stable, reflecting a slower water source renewal process with minimal seasonal influence. Through quantitative comparisons of the evaporation line’s slope and intercept, this study finds that precipitation is most significantly affected by evaporation, while groundwater is least influenced, showing more stable isotope characteristics. Climate and topography in high-altitude areas significantly regulate water isotope characteristics, especially during the dry season, where evaporation plays a dominant role in the enrichment of precipitation and river water isotopes. This study innovatively establishes an evidence framework for the linkage of multiple water body isotopes, revealing the “seasonal strong fluctuations + differential water body responses + high-altitude regulation” mechanism of water isotopes in alpine arid regions. It provides new data support for water resource management, particularly in aspects such as water source allocation during the dry season, groundwater protection, and evaporation enrichment effect prediction. Future research could expand the sample size and integrate multi-source data and hydrological models to further improve the accuracy of hydrological process predictions, offering more precise support for watershed water resource management and ecological protection. Full article

(This article belongs to the Special Issue Applications of Stable Isotopes in Understanding Hydrological and Hydrochemical Processes)

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20 pages, 3156 KB

Open AccessArticle

Environmental Impact of a Portable Nature-Based Solution (NBS) Coupled with Solar Photocatalytic Oxidation for Decentralized Wastewater Treatment

by Lobna Mansouri, Sabrine Saadellaoui, Riccardo Bresciani, Khaoula Masmoudi, Hanen Jarray, Thuraya Mellah, Ahmed Ghrabi, Hanene Akrout, Latifa Bousselmi and Fabio Masi

Water 2026, 18(3), 422; https://doi.org/10.3390/w18030422 - 5 Feb 2026

Abstract

This study presents a life cycle assessment of a low-cost pilot-scale wastewater treatment system that combines solar photocatalytic oxidation with Nature-based Solutions (NBSs) for a specially constructed wetland (CW). The prototype was designed and assessed for its efficiency in treating urban wastewater and [...] Read more.

This study presents a life cycle assessment of a low-cost pilot-scale wastewater treatment system that combines solar photocatalytic oxidation with Nature-based Solutions (NBSs) for a specially constructed wetland (CW). The prototype was designed and assessed for its efficiency in treating urban wastewater and its environmental impact on agricultural irrigation reuse. Evaluations were performed with the SimaPro software, applying the Impact ReCiPe Medpoint methodology, which includes characterization and selection of the relevant environmental issues steps. The results demonstrate the potential of this hybrid system for providing high-quality treated wastewater suitable for agricultural reuse in water-scarce regions. The analysis reveals that the operational phase, mainly driven by energy consumption for pumping, aeration, and photocatalytic processes, accounts for over 85–98% of the total global warming potential (GWP), primarily due to reliance on fossil-based electricity. Conversely, the construction phase significantly impacts land use and toxicity categories, with concrete and substrate production contributing around 95% to land occupation and 97% to human toxicity. The photocatalytic subsystem also contributes notably to embodied carbon at 42.4%, owing to energy-intensive manufacturing. The results underscore the importance of optimizing operational energy efficiency and selecting sustainable materials to mitigate environmental burdens. The integrated system demonstrates promising potential for producing high-quality treated effluent suitable for agricultural reuse in water-scarce regions, supporting sustainable water management. These findings provide important insights for reducing ecological impacts and advancing environmentally sustainable wastewater treatment solutions. Full article

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

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22 pages, 3975 KB

Open AccessArticle

Projected Future Trends in Runoff and Sediment Transport in Typical Rivers of the Yellow River Basin, China

by Beilei Liu, Yongbin Wei, Chuanming Wang, Xiaorong Chen, Pan Wang, Jianye Ma and Peng Li

Water 2026, 18(3), 421; https://doi.org/10.3390/w18030421 - 5 Feb 2026

Abstract

This study systematically evaluated the response mechanisms of water and sediment processes in the Kuye River Basin to climate change and human activities from 2023 to 2053 by integrating multi-source climate scenarios (CMIP5 models), land-use change projections (based on the Markov chain model), [...] Read more.

This study systematically evaluated the response mechanisms of water and sediment processes in the Kuye River Basin to climate change and human activities from 2023 to 2053 by integrating multi-source climate scenarios (CMIP5 models), land-use change projections (based on the Markov chain model), and a distributed hydrological model (SWAT model). The results indicate that under the RCP8.5 high-emission scenario, annual precipitation in the basin shows a non-significant increasing trend but with intensified interannual variability. Spatially, precipitation exhibits a pattern of increasing from northwest to southeast, with a marked decadal transition occurring around 2043. Land-use structure undergoes significant transformation, with construction land projected to account for 30.54% of the total basin area by 2050, while grassland and cropland continue to decline. Water and sediment processes display distinct phased characteristics: a fluctuating adjustment phase (2023–2033), a relatively stable phase (2034–2043), and a sharp growth phase (2044–2053). Parameter sensitivity analysis identifies the curve number (CN2) and soil bulk density (SOL_BD) as key regulatory parameters, revealing the synergistic mechanism by which land-use changes amplify climatic effects through alterations in surface properties. Based on the findings, an adaptive watershed management framework is proposed, encompassing dynamic water resource regulation, spatial zoning, targeted erosion control, and iterative scientific management. Particular emphasis is placed on addressing hydrological transition risks around 2043 and promoting low-impact development practices in high-erosion areas. This study provides a scientific basis for the integrated management of water and soil resources in the context of ecological conservation and high-quality development in the Yellow River Basin. The methodology developed herein offers a valuable reference for predicting water and sediment processes and implementing adaptive management in similar semi-arid basins. Full article

(This article belongs to the Special Issue Soil Erosion and Soil and Water Conservation, 2nd Edition)

27 pages, 6053 KB

Open AccessArticle

Riverbed Evolution Trends Based on the Channel-Forming Discharge Concept: A Climate Change Scenario Analysis to 2100 for the Ialomița River, Romania

by Andrei Radu, Laura Comănescu, Nicu Ciobotaru and Romulus Costache

Water 2026, 18(3), 420; https://doi.org/10.3390/w18030420 - 5 Feb 2026

Abstract

Nowadays, river systems exhibit significant geomorphic changes that primarily reflect their response to the climate signal, driven by ongoing climate change. In this context, detecting future trends in riverbed dynamics is crucial, especially from a river management perspective. The purpose of the study [...] Read more.

Nowadays, river systems exhibit significant geomorphic changes that primarily reflect their response to the climate signal, driven by ongoing climate change. In this context, detecting future trends in riverbed dynamics is crucial, especially from a river management perspective. The purpose of the study is to identify long-term trends in riverbed evolution at the Băleni gauging station on the Ialomița River, based on the channel-forming discharge concept, through the end of the 21st century. To achieve this, a comprehensive methodology was developed that primarily focuses on calculating the effective discharge (Qe) as a key driver of riverbed dynamics, using discharges simulated by the E–HYPE hydrological model forced by eight EURO–CORDEX EUR–11 ensemble climate projections under the RCP 4.5 and RCP 8.5 scenarios up to 2100. The results of the study indicate Qe values ranging between 7.49 m³/s and 12.79 m³/s for RCP 4.5, and between 5.66 m³/s and 13.94 m³/s for RCP 8.5. Based on the ensemble mean of Qe, different riverbed evolution trends and are identified: a state of dynamic equilibrium under RCP 4.5, suggesting that the riverbed is probable to maintain its geomorphological state similar to the present; and pronounced variability under RCP 8.5, indicating intense erosion processes until mid-century, followed by a slight aggradation trend that may intensify at the end of the century, with Qe being 23.27% lower than the reference period. Overall, the Qe_8.5 evolution suggests a potential future alteration of the Ialomița riverbed. Beyond its main findings, this study provides a methodological framework for assessing future effective discharge and may support river management and restoration planning in the study area. Full article

(This article belongs to the Section Water Erosion and Sediment Transport)

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25 pages, 7021 KB

Open AccessArticle

Decadal Runoff Variability Under Moderate and Extreme Climate Scenarios: A SWAT Modeling Study for a Postglacial Lowland Catchment (NW Poland)

by Mikołaj Majewski, Witold Bochenek and Joanna Gudowicz

Water 2026, 18(3), 419; https://doi.org/10.3390/w18030419 - 5 Feb 2026

Abstract

The study investigates the projected impact of climate change on water runoff in the upper Parsęta catchment, a postglacial lowland basin located in northwestern Poland. In the first step of the analysis, hydrological simulations for the period 2005–2022 were conducted using the Soil [...] Read more.

The study investigates the projected impact of climate change on water runoff in the upper Parsęta catchment, a postglacial lowland basin located in northwestern Poland. In the first step of the analysis, hydrological simulations for the period 2005–2022 were conducted using the Soil and Water Assessment Tool (SWAT). Model calibration and validation, performed in SWAT-CUP with the SUFI2 algorithm, yielded satisfactory performance (R² = 0.66–0.80; PBIAS = 0.43–13.87). Based on the calibrated model, projected simulations were performed for three future decades (2021–2030, 2031–2040, and 2041–2050) under two Representative Concentration Pathways (RCP4.5 and RCP8.5). Climate input data were derived from the KLIMADA 2.0 national database, which was developed using down-scaled regional climate model output from the EURO-CORDEX ensemble and statistical bias-correction methods to generate high-resolution projections. Under RCP4.5, mean annual runoff increased by approximately 13–26%, while under RCP8.5, the changes were more variable, ranging from 2% to 28% relative to the 2011–2020 baseline. Seasonal analyses revealed enhanced autumn–winter runoff and lower spring–summer flows. The findings highlight that moderate climate forcing can lead to substantial alterations in hydrological regimes in postglacial lowland catchments, in certain decades comparable in magnitude to those projected under extreme forcing, underscoring the need for adaptive water management in northern Poland. Full article

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

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