-
Impacts of Climatic Phenomena and Terrain on December 2021 Extreme Rainfall over Peninsular Malaysia -
Machine Learning in Climate Downscaling: A Critical Review of Methodologies, Physical Consistency, and Operational Applications -
Long-Term VOC Transport in a Thick Heterogeneous Vadose Zone and Perched Aquifers: Jerusalem Mountains Industrial Site -
Leakage Modelling in Water Distribution Networks: A Novel Framework for Embedding FAVAD Formulation into EPANET 2.2 -
Distributive Disturbances: Examining Community Exposure to Drinking Water Contaminants Amidst the Jackson, Mississippi (USA) Water Crisis
Journal Description
Water
Water
is a peer-reviewed, open access journal on water science and technology, including the ecology and management of water resources, published semimonthly online by MDPI. Water collaborates with the Stockholm International Water Institute (SIWI). In addition, the American Institute of Hydrology (AIH), Polish Limnological Society (PLS) and Japanese Society of Physical Hydrology (JSPH) are affiliated with Water and their members receive a discount on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Ei Compendex, GEOBASE, GeoRef, PubAg, AGRIS, CAPlus / SciFinder, Inspec, and other databases.
- Journal Rank: JCR - Q2 (Water Resources) / CiteScore - Q1 (Aquatic Science)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 18.9 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2025).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Companion journals for Water include: Hydropower and Freshwater.
- Journal Clusters of Water Resources: Water, Journal of Marine Science and Engineering, Hydrology, Resources, Oceans, Limnological Review, Coasts.
Impact Factor:
3.5 (2025);
5-Year Impact Factor:
3.6 (2025)
Latest Articles
Metagenomic Insights into Taxonomic Structure, Function of Microbial Community and Antibiotic Resistance Genes in the Whole Baihe Basin
Water 2026, 18(12), 1524; https://doi.org/10.3390/w18121524 (registering DOI) - 20 Jun 2026
Abstract
Plateau waters in Northern Sichuan, China, act as critical headwaters of the Yellow River. Microbial communities in water bodies and soil matrices within this region are increasingly pressured by intensive animal rearing; yet few studies have characterized microbial shifts across entire riverine niches.
[...] Read more.
Plateau waters in Northern Sichuan, China, act as critical headwaters of the Yellow River. Microbial communities in water bodies and soil matrices within this region are increasingly pressured by intensive animal rearing; yet few studies have characterized microbial shifts across entire riverine niches. In this study, we employed next-generation sequencing based metagenomics to investigate microbial features, community structure and diversity, metabolic potentials, and antibiotic resistance genes (ARGs) in the Baihe River, a tributary in the source region of the Yellow River. Sampling locations covered the main stem and three tributaries of the Baihe River, spanning from its source, through upstream and downstream segments, to the convergence site with the main stem of the Yellow River. Results revealed that Pseudomonadota and Bacteroidota were the most abundant phyla. The relative abundance of most taxa at multiple taxonomic levels exhibited an increasing trend along the river continuum driven by rising total nitrogen (TN) and total phosphorus (TP) concentrations; however, a notable exception occurred at BH1 (the Baihe source), where the abundance of numerous taxa was markedly higher than in downstream samples. We detected abundant ARGs predominantly associated with antibiotic resistance. Furthermore, prevalent viruses affiliated with the phyla Uroviricota and Nucleocytoviricota, together with pathogenic bacteria, were identified as etiological agents of diverse infectious diseases. This study provides novel perspectives for managing aquatic contamination in plateau river ecosystems by linking environmental variables, microbial succession, and resistome distribution.
Full article
(This article belongs to the Section Biodiversity and Functionality of Aquatic Ecosystems)
►
Show Figures
Open AccessArticle
Few-Shot Learning–Based Water Quality Classification Under Limited Data Conditions for Smart Aquaculture Monitoring
by
Ashikur Rahman, Gwo Chin Chung, Yin Hoe Ng, Kah Yoong Chan and Soo Fun Tan
Water 2026, 18(12), 1523; https://doi.org/10.3390/w18121523 (registering DOI) - 20 Jun 2026
Abstract
Water quality monitoring is a fundamental element of sustainable aquaculture management, as changes in parameters of physicochemical and biological properties directly affect the health, growth performance, and productivity of the aquaculture systems. Although traditional machine learning (ML) methods have demonstrated effectiveness in water
[...] Read more.
Water quality monitoring is a fundamental element of sustainable aquaculture management, as changes in parameters of physicochemical and biological properties directly affect the health, growth performance, and productivity of the aquaculture systems. Although traditional machine learning (ML) methods have demonstrated effectiveness in water quality classification, their performance often depends on large amounts of labeled data, which can be challenging and expensive to collect in real-world aquaculture environments. This study explores a few-shot learning (FSL) framework for data-efficient water quality classification under limited supervision to address this limitation. Several FSL models, including prototypical networks (ProtoNet), Siamese Networks, and Matching Networks were developed and evaluated in a comparative experimental framework against the traditional machine learning classifiers logistic regression, random forest, support vector machine and extreme gradient boosting. Low-data learning scenarios were simulated using a structured episodic evaluation approach. Experimental results demonstrate FSL techniques outperform traditional machine learning methods across all evaluated scenarios. Among the tested methods, ProtoNet achieved the highest performance, attaining an accuracy of 94.46% and an ROC-AUC score of 98.65%, indicating superior discriminative capability and robustness. Siamese Networks also demonstrated competitive performance under highly constrained data conditions. Furthermore, latent-space visualization, confusion matrix analysis, paired t-test statistical analysis, and ablation studies confirmed that episodic meta-learning enables the learning of highly discriminative latent representations with strong generalization capability under limited labeled data conditions. The findings highlight that FSL provides a robust and scalable framework for intelligent water quality classification in aquaculture systems, particularly in scenarios where labeled data are scarce, offering significant potential for sustainable aquaculture monitoring applications.
Full article
(This article belongs to the Special Issue Water Quality Management for Sustainable Aquaculture: Integrating Multi-Omics, Digital Technologies, and Climate Resilience)
►▼
Show Figures

Figure 1
Open AccessArticle
Lagged Responses of Vegetation Growth to Hydrometeorological Drivers Across Complex Terrain in Southwest China
by
Ting Chen, Guocai Xiong, Zhanxin Gao, Zhijie Song, Jingyi Zhang, Dandan Dong and Hui Chen
Water 2026, 18(12), 1522; https://doi.org/10.3390/w18121522 (registering DOI) - 20 Jun 2026
Abstract
Vegetation is an important component of ecosystems and plays an important role in carbon balance, water balance, and energy conversion. The spatial and temporal changes in the normalized difference vegetation index (NDVI), water resources, and hydrometeorological factors in southwest China between 2003 and
[...] Read more.
Vegetation is an important component of ecosystems and plays an important role in carbon balance, water balance, and energy conversion. The spatial and temporal changes in the normalized difference vegetation index (NDVI), water resources, and hydrometeorological factors in southwest China between 2003 and 2020 were investigated using multisource remote sensing data. Correlation analyses were performed to assess the correlation among NDVI, water resource changes, and hydrometeorological factors with different time lags. A stepwise regression model with different lag times was constructed to clarify the effects of four topographic factors and eight climatic factors on NDVI, and the following conclusions were obtained: (1) NDVI increased from 2003 to 2020, and the increase became obvious after 2012. (2) NDVI was considerably affected by alterations in the soil water content caused by natural changes. The correlation of NDVI with evapotranspiration and precipitation was high, followed by NDVI’s correlation with surface temperature. The spatial distribution of the positive correlation between NDVI and evapotranspiration and NDVI and precipitation was relatively consistent, and a positive correlation was observed in most parts of Southwest China. (3) The hydrometeorological factors mainly affected NDVI with a lag of 0–1 month, and the correlation was high in western Sichuan and most of Yunnan. In Yunnan, Available Water Capacity (AWC) affected NDVI with a lag of 0–2 months; the lag was 0–1 month in western Yunnan and 1–2 months in eastern Yunnan. (4) In terms of different vertical heights, the NDVI in the regions with altitudes higher than 3000 m was affected by climate change, especially evapotranspiration and precipitation. (5) Digital Elevation Model (DEM), Latitude (Lat), Evapotranspiration (ET), Precipitation (PRCP), Land Surface Temperature (LST), and NDVI were closely related in the construction of stepwise regression models with different lag times.
Full article
(This article belongs to the Section Ecohydrology)
►▼
Show Figures

Figure 1
Open AccessArticle
Identification of Testate Amoeba Communities and Their Influencing Factors in Dali Lake
by
Biao Sun, Yuying Guo, Chunling Wang and Zhilei Zhen
Water 2026, 18(12), 1521; https://doi.org/10.3390/w18121521 (registering DOI) - 20 Jun 2026
Abstract
The shells of testate amoebae are decay-resistant and well preserved in lake sediments, making them excellent biological indicators of climate change. In this study, the identification method for testate amoebae was initially optimized based on the collection of surface sediments from Dali Lake,
[...] Read more.
The shells of testate amoebae are decay-resistant and well preserved in lake sediments, making them excellent biological indicators of climate change. In this study, the identification method for testate amoebae was initially optimized based on the collection of surface sediments from Dali Lake, and statistical analyses were conducted to investigate the community distribution characteristics and key environmental factors driving the testate amoeba species composition. According to the results, the testate amoeba species diversity in the surface sediments of Dali Lake was relatively low. A total of eight species belonging to five genera were identified, and the dominant species were Arcella discoides (35.64% of the total abundance), Phryganella acropodia (24.75%), and Arcella gibbosa (11.39%). All the identified testate amoeba taxa are common in global freshwater sediments, and no new species was discovered in this study. The testate amoeba community composition exhibited strong correlations with the total organic carbon, total nitrogen, dissolved inorganic phosphorus, and total phosphorus and weak correlations with the electrical conductivity and Chlorophyll-a.
Full article
(This article belongs to the Section Biodiversity and Functionality of Aquatic Ecosystems)
►▼
Show Figures

Figure 1
Open AccessProject Report
Regional Assessment of Groundwater Flow of Natural and Predicted Resources of Fresh and Low-Mineralized Waters in Southern and Western Kazakhstan
by
Dinara Adenova, Janay Sagin, Malis Absametov, Yermek Murtazin and Vladimir Smolyar
Water 2026, 18(12), 1520; https://doi.org/10.3390/w18121520 (registering DOI) - 20 Jun 2026
Abstract
Groundwater flow is an integral part of the Earth’s water cycle and plays a key role in assessing groundwater resource potential, characterizing the upper limit of possible groundwater withdrawal over a long period without depletion. The objective of this study is a comprehensive
[...] Read more.
Groundwater flow is an integral part of the Earth’s water cycle and plays a key role in assessing groundwater resource potential, characterizing the upper limit of possible groundwater withdrawal over a long period without depletion. The objective of this study is a comprehensive regional assessment of groundwater flow and the natural and predicted resources of fresh and low-mineralized groundwater in Southern and Western Kazakhstan. This assessment is based on an analysis of hydrogeological conditions and water balance, taking into account climate variability and anthropogenic load, to justify sustainable water resources management in arid territories. This article provides a regional assessment and mapping of groundwater flow, taking into account climate and anthropogenic changes in Kazakhstan, to refine the predicted resources of fresh and low-mineralized groundwater. The basin balance calculation results indicate that in arid and semi-arid regions, the decline in groundwater recharge by the 2050s will generally not exceed 10%. The average layer of groundwater flow of renewable groundwater resources in the Kazakhstan part of the Zhaiyk-Caspian water management basin (WMB) is estimated at 33.4 mm/year, and the average modulus of groundwater flow is 1.06 L/s per 1 km2. The average layer of groundwater flow of renewable groundwater resources in the Kazakhstan part of the Aral-Surdarya water management basin (WMB) is estimated at 14.8 mm/year, and the average modulus of groundwater flow is 0.47 L/s per 1 km2. The average layer of groundwater flow of renewable groundwater resources in the Kazakhstan part of the Shu-Talas water management basin (WMB) is estimated at 26.5 mm/year, and the average modulus of groundwater flow is 0.84 L/s per 1 km2. For mountainous and folded regions, the average layer of groundwater flow of renewable groundwater resources in the Balkhash-Alakol water management basin (WMB) system is estimated at 70.7 mm/year, and the average modulus of groundwater flow is 2.24 L/s per 1 km2. For intermontane and foothill basins, the average layer of groundwater flow of renewable groundwater resources in the Balkhash-Alakol water management basin (WMB) is estimated at 54.3 mm/year, and the average modulus of groundwater flow is 1.72 L/s per km2.
Full article
(This article belongs to the Topic Human Impact on Groundwater Environment, 2nd Edition)
►▼
Show Figures

Figure 1
Open AccessArticle
Coastal Water Quality Degradation by Virulent and Antibiotic-Resistant Enteric Pathogens: Seasonal Patterns and Anthropogenic Drivers in the Jaffna Peninsula, Sri Lanka
by
Meddage Anjana Kelum Mithurangana Madhura Kumara, Pathmalal Marakkale Manage, Ganepola Arachchilage Pradeep Ruchitha Ganepola, Ponnamperuma Arachchige Kasun Chamara Wijerathna, Weiping Liu and Shanshan Yin
Water 2026, 18(12), 1519; https://doi.org/10.3390/w18121519 (registering DOI) - 20 Jun 2026
Abstract
Tropical coastal waters are increasingly recognized as critical reservoirs for virulent, antibiotic-resistant enteric pathogens, yet seasonal dynamics governing their spatial distribution remain poorly characterized. We hypothesized that hydrological shifts and anthropogenic nutrient enrichment drive the seasonal distribution, virulence profiles, and antimicrobial resistance (AMR)
[...] Read more.
Tropical coastal waters are increasingly recognized as critical reservoirs for virulent, antibiotic-resistant enteric pathogens, yet seasonal dynamics governing their spatial distribution remain poorly characterized. We hypothesized that hydrological shifts and anthropogenic nutrient enrichment drive the seasonal distribution, virulence profiles, and antimicrobial resistance (AMR) of Escherichia coli, Salmonella spp., and Shigella spp. in the Jaffna Peninsula, Sri Lanka. Across 25 coastal sites during dry and transitional seasons, we integrated physicochemical water quality assessment, culture-based enumeration, PCR-based virulence gene profiling, Minimum Inhibitory Concentration (MIC) assays, GIS mapping, and statistical analyses. Key water quality parameters, including ammonium, nitrite, and total phosphorus, showed significant seasonal variation (p < 0.05), reflecting distinct hydrological regimes across seasons. A total of 220 E. coli, 200 Salmonella spp., and 100 Shigella spp. isolates were examined for virulence gene profiles and antibiotic tolerance. E. coli was detected at 80–88% of sites, Salmonella spp. at 72–88%, and Shigella spp. at 32–48%. Among E. coli isolates, stx1 was detected at 20–28% of sites and eae at 16% across both seasons. The stn gene was detected in Salmonella spp. at 12–28% of sites seasonally. Virulence profiling confirmed STEC harbouring stx1, stx2, and eae; Salmonella spp. carried stn; and Shigella spp. possessed invasion-associated genes. Trimethoprim–sulfamethoxazole resistance was recorded in 63.2% of E. coli, 33.0% of Salmonella spp., and 31.0% of Shigella spp. isolates at the lowest tested concentration of 4 µg/mL., while ciprofloxacin and piperacillin–tazobactam retained greater efficacy. Correlation analyses revealed significant associations among faecal contamination, nutrient enrichment, and virulence gene prevalence, implicating untreated sewage discharge and eutrophication as likely ecological factors associated with pathogen occurrence. These findings designate the Jaffna coastal zone as a significant reservoir of virulent AMR enteric pathogens, underscoring the urgent need for integrated One Health surveillance and seasonally adaptive coastal water quality management.
Full article
(This article belongs to the Special Issue Pollution Mechanisms and Source Apportionment of Typical Pollutants in Aquatic Environments, 2nd Edition)
►▼
Show Figures

Figure 1
Open AccessArticle
Monitoring-Based Assessment of Fluoride Exposure and Health Risks via Drinking Water in the Taruo Lake Region, Tibetan Plateau
by
Weimin Xie, Bingyang Wang, Jianghuan Hua, Mingyang Li, Gezi Li, Fan Xia, Tao Zuo and Xiaochen Wang
Water 2026, 18(12), 1518; https://doi.org/10.3390/w18121518 (registering DOI) - 19 Jun 2026
Abstract
Excessive fluoride intake from drinking water remains a public health concern in geogenic high-fluoride regions, yet direct evidence linking environmental fluoride levels to internal exposure in remote high-altitude areas is limited. This study integrated environmental monitoring with human biomonitoring to assess fluoride exposure
[...] Read more.
Excessive fluoride intake from drinking water remains a public health concern in geogenic high-fluoride regions, yet direct evidence linking environmental fluoride levels to internal exposure in remote high-altitude areas is limited. This study integrated environmental monitoring with human biomonitoring to assess fluoride exposure and health risks in the Taruo Lake region of the Tibetan Plateau. Surface water (n = 45 for Taruo Lake; n = 8 for its tributaries) and groundwater samples (n = 4) were collected and analyzed for fluoride concentrations, and blood ionic fluoride (BIF) levels were measured in 122 local residents (47 adults, 75 children). The results showed that fluoride concentrations in most surface water tributaries of Taruo Lake and groundwater sources were below China’s drinking water standard, whereas those in Taruo Lake exceeded this limit (routine monitoring mean 2.54 mg/L; multi-site mean 2.79 mg/L). BIF levels were significantly higher in adults (0.126 ± 0.041 mg/L) than in children (0.075 ± 0.032 mg/L) and showed a positive correlation with age (r = 0.533, p < 0.001). Notably, 23.4% of adults and 1.3% of children exceeded 0.15 mg/L, an empirical threshold typical for healthy populations in non-endemic areas. Based on the hazard quotient (HQ) model recommended by the US EPA, most drinking water sources posed acceptable non-carcinogenic risks (HQ < 1). In contrast, Taruo Lake water presented an elevated risk (HQ > 1) in 2024 primarily due to the regional geological background, and although not used for daily drinking, this finding offers an indicative reference for local water management and risk prevention. This preliminary monitoring and biomonitoring assessment provides baseline data for future studies and underscores the necessity of continuous surveillance and evaluation of total dietary fluoride intake to protect the health of this vulnerable high-altitude population.
Full article
(This article belongs to the Special Issue Elemental and Isotopic Geochemistry Tracing of Aquatic Pollutants: Source Apportionment and Ecological Health Risk)
Open AccessArticle
A Case Study of the First Known Relocation of an Imperiled Burrowing Crayfish Species, Cambarus pauleyi—Meadow River Mudbug: Results and Implications
by
David A. Foltz II and Zachary J. Loughman
Water 2026, 18(12), 1517; https://doi.org/10.3390/w18121517 (registering DOI) - 19 Jun 2026
Abstract
Burrowing crayfish are among the most important keystone species in North American ecosystems, yet they remain poorly understood. The Meadow River Mudbug (Cambarus pauleyi), native to West Virginia, was only recently described and is known from a very limited range in
[...] Read more.
Burrowing crayfish are among the most important keystone species in North American ecosystems, yet they remain poorly understood. The Meadow River Mudbug (Cambarus pauleyi), native to West Virginia, was only recently described and is known from a very limited range in the Central Appalachians. During planning for an interstate pipeline, two large populations of C. pauleyi were found in the proposed right-of-way. As part of environmental compliance, salvage, relocation, and monitoring for the species were conducted from 2018 to 2024. All C. pauleyi were moved to the Meadow River Wildlife Management Area, where artificial starter burrows were created, and exclusion baskets were placed over them to prevent predation, the process of which is described herein. Monitoring showed a two-month survival rate of 74.0% to 85.5%. These results are promising for the future restoration of burrowing crayfish and other species that rely on crayfish burrows for habitat.
Full article
(This article belongs to the Special Issue Ecology and Management of Crayfish)
►▼
Show Figures

Figure 1
Open AccessReview
Challenges and Development Trends of Crop–Hydro Digital Twin Technology
by
Shihan Wang, Jiaqing He, Aidi Huo, Yapeng Li, Yibing Cao, Salah Elsayed and Jahangir Muhammad Ilyas
Water 2026, 18(12), 1516; https://doi.org/10.3390/w18121516 (registering DOI) - 19 Jun 2026
Abstract
Under the dual constraints of global food security and ecological protection, conventional agriculture is hampered by low resource efficiency and sluggish environmental response. Crop digital twin technology establishes a dynamic virtual reality system that integrates crops, environment, and water to enable real-time interaction
[...] Read more.
Under the dual constraints of global food security and ecological protection, conventional agriculture is hampered by low resource efficiency and sluggish environmental response. Crop digital twin technology establishes a dynamic virtual reality system that integrates crops, environment, and water to enable real-time interaction and optimization. Based on the existing literature, this paper reviews the concept, architecture, and core modules of this technology and summarizes its applications in precision irrigation and crop monitoring. There are three major bottlenecks that persist, including limited high-frequency multi-source sensing and spatiotemporal fusion, insufficient parameter calibration and dynamic updating, and weak cross-scale integration from plant to watershed. Water is increasingly recognized as the key constraint and control variable and acting as both the central physiological driver of crop growth and the mass-flow link that connects the soil–plant–atmosphere continuum. The spatiotemporal dynamics of crop water deficit, compensatory root water uptake, evapotranspiration feedback, and the hydraulic behavior of irrigation-district canal systems constitute the core hydrological processes that must be simulated within the digital twin. Synchronizing crop water demand, soil moisture dynamics, atmospheric evapotranspiration, and irrigation scheduling within a unified spatiotemporal framework establishes a complete sensing, diagnosis, prediction and regulation technical chain. This chain offers a core pathway for alleviating agricultural water scarcity, improving irrigation efficiency, and ensuring food security.
Full article
(This article belongs to the Special Issue Application of Water-Saving Irrigation in Agricultural Development)
►▼
Show Figures

Figure 1
Open AccessArticle
An Empirical Conditional Model for Estimating Wave Characteristics from Wind Speed, Fetch, and Depth: Application to the Red Sea
by
Muhnad Almasoudi, Soroosh Sharifi and Hassan Hemida
Water 2026, 18(12), 1515; https://doi.org/10.3390/w18121515 (registering DOI) - 19 Jun 2026
Abstract
An empirical model is developed to predict significant wave height and significant wave period using only wind speed at 10 m height, fetch, and water depth. The model distinguishes between fetch-limited and duration-limited sea states within a conditional empirical framework that incorporates modified
[...] Read more.
An empirical model is developed to predict significant wave height and significant wave period using only wind speed at 10 m height, fetch, and water depth. The model distinguishes between fetch-limited and duration-limited sea states within a conditional empirical framework that incorporates modified empirical exponents and corrections into classical wave formulations. Validation was performed using wind and wave data from the Global Forecast System at 26 coastal and offshore stations distributed across eleven different pilot seas and oceans worldwide, encompassing a broad spectrum of marine environments and climatic conditions. The proposed model was benchmarked against established empirical approaches. Results indicate a mean prediction error of 6.6% for the significant wave height and 9.6% for the significant wave period, substantially outperforming conventional formulations whose errors exceed 50% under comparable conditions. Unlike existing empirical models that are restricted to specific regions or sea-state conditions, the proposed model demonstrated strong predictive performance across diverse seas, oceans, and climatic conditions, enabling more reliable wave predictions in data-scarce and dynamically complex marine environments. The developed model was further applied to the Red Sea, where it successfully reproduced the spatial variability of significant wave height and wave period. From the results, it has been found that the developed model provides a practical and transferable tool for wave forecasting, coastal engineering, and offshore renewable energy applications.
Full article
(This article belongs to the Special Issue Recent Advances in Hydraulic Machinery and Its Application in Marine Engineering)
Open AccessSystematic Review
Urban Water Insecurity and Public Health in Kathmandu Valley, Nepal: A Systematic Review of Contamination Sources, Health Risks, and Governance Gaps
by
Ganga B. Basnet and Samendra Sherchan
Water 2026, 18(12), 1514; https://doi.org/10.3390/w18121514 (registering DOI) - 19 Jun 2026
Abstract
Urban water insecurity is an increasingly critical challenge in rapidly urbanizing regions of the Global South, driven by population growth, environmental degradation, infrastructure limitations, and institutional constraints. Kathmandu Valley, Nepal, exemplifies these interconnected pressures. This study presents a systematic review of 45 peer-reviewed
[...] Read more.
Urban water insecurity is an increasingly critical challenge in rapidly urbanizing regions of the Global South, driven by population growth, environmental degradation, infrastructure limitations, and institutional constraints. Kathmandu Valley, Nepal, exemplifies these interconnected pressures. This study presents a systematic review of 45 peer-reviewed and selected grey literature sources published between 2000 and 2025, conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were included if they examined drinking water contamination, public health risks, household coping practices, wastewater-related exposure, or governance dynamics in Kathmandu Valley, Nepal. Findings were synthesized using a narrative thematic approach. The review identifies widespread contamination across municipal supply systems, groundwater, tanker water, traditional water sources, and household-stored water. Microbial contamination, particularly total coliforms, fecal coliforms, and Escherichia coli, emerged as the most consistently reported and immediate public health concern. Chemical and physicochemical contaminants, including ammonia, iron, arsenic, nitrate, and turbidity, were also widely reported, especially in shallow and deep groundwater systems. Seasonal dynamics further influenced exposure risks, with increased microbial contamination during monsoon periods and greater dependence on alternative and less regulated water sources during dry seasons. The findings further indicate that unsafe water exposure is associated with a substantial burden of waterborne diseases and emerging risks such as antimicrobial resistance. Although household water treatment practices reduced contamination in some cases, risks often persisted due to recontamination during storage and handling. These burdens disproportionately affected marginalized and peri-urban populations with limited access to safe and reliable water infrastructure. The review also highlights persistent governance challenges, including institutional fragmentation, weak regulatory enforcement, inadequate infrastructure investment, and growing dependence on informal water supply systems. Together, these conditions contribute to a hybrid urban water system in which formal and informal sources coexist without consistent quality control. Overall, the evidence demonstrates that water insecurity in Kathmandu Valley is a systemic condition shaped by the interaction of environmental contamination, unequal exposure, household coping limitations, and fragmented governance. By integrating environmental, public health, and governance evidence, this review advances understanding of urban water insecurity in rapidly urbanizing contexts and highlights the need for integrated, equity-oriented, and governance-informed interventions. These findings have broader relevance for cities across the Global South experiencing similar environmental and infrastructural pressures.
Full article
(This article belongs to the Special Issue Water Quality, Pathogens, and Public Health Risks)
►▼
Show Figures

Graphical abstract
Open AccessArticle
Chemical-Free Regeneration of Scaled Capacitive Deionization Electrodes Using Alternating Polarization
by
Yazeed Algurainy
Water 2026, 18(12), 1513; https://doi.org/10.3390/w18121513 - 19 Jun 2026
Abstract
Mineral scaling on carbon electrodes remains a critical limitation to the long-term performance of capacitive deionization (CDI) systems treating hard and alkaline waters. In this study, alternating polarization (AP) is investigated as an in situ electrochemical regeneration strategy to reverse cathodic scaling in
[...] Read more.
Mineral scaling on carbon electrodes remains a critical limitation to the long-term performance of capacitive deionization (CDI) systems treating hard and alkaline waters. In this study, alternating polarization (AP) is investigated as an in situ electrochemical regeneration strategy to reverse cathodic scaling in flow-through CDI treating a feed containing 5 mM NaCl, 5 mM NaHCO3, and 2.5 mM CaCl2 under three modes: conventional cycling (control), delayed AP introduced after fouling developed, and immediate AP implemented from the first cycle. Under conventional operation, cathodic scaling reduced the salt adsorption capacity (SAC) to 5.9 ± 0.2 mg/g, increased cathode mass from 0.208 ± 0.004 g (pristine) to 0.353 ± 0.054 g, and decreased specific capacitance to 28 ± 2 F/g, accompanied by extensive pore blockage and carbonate deposition observed by SEM and BET measurements. Application of delayed AP restored electrode functionality, increasing SAC to 8.9 ± 0.6 mg/g and specific capacitance to 56 ± 2 F/g while reducing the cathode mass to 0.212 ± 0.007 g and removing surface precipitates. The immediate AP operation reduced the extent of scale formation from cycle 1, maintaining SAC at 8.4 ± 0.2 mg/g throughout operation, with stable physical and electrochemical properties. These improvements are attributed to periodic polarity reversal, which induces alternating alkaline and acidic microenvironments at the electrode surface and promotes the electrochemical dissolution of carbonate phases during anodic polarization. Overall, this work establishes AP as a simple, chemical-free operational strategy for both preventing and reversing cathodic mineral scaling, thereby enabling sustained CDI performance and mitigating capacity loss over the tested operational periods in complex water matrices.
Full article
(This article belongs to the Section Water Quality and Contamination)
►▼
Show Figures

Figure 1
Open AccessArticle
Bridging the Laboratory–Field Divide: Challenges and Opportunities in the ALPSTREAM Eco-Hydraulic Experimental Outdoor Mesocosm
by
Tiziano Bo, Anna Marino, Margherita Abbà, Francesca Bona, Elisa Falasco, Marta Moriondo and Stefano Fenoglio
Water 2026, 18(12), 1512; https://doi.org/10.3390/w18121512 - 19 Jun 2026
Abstract
The use of mesocosms in stream ecology has long attracted the attention of researchers due to the clear advantages these systems offer for manipulative experiments. Despite some limitations, they provide an effective way to create semi-natural conditions in which selected parameters can be
[...] Read more.
The use of mesocosms in stream ecology has long attracted the attention of researchers due to the clear advantages these systems offer for manipulative experiments. Despite some limitations, they provide an effective way to create semi-natural conditions in which selected parameters can be artificially controlled. This study presents the ALPSTREAM eco-hydraulic laboratory, a mesocosm system designed to mimic the conditions of an alpine stream (Ostana, NW Italy). The structure of this system is unique and consists of six 25-m-long flumes, fed directly by the Po River and equipped to regulate key hydraulic parameters. The paper describes the structure of this system and presents two case studies to illustrate some potential applications. The first aimed to analyze the impact of different aquatic insects (scrapers) on periphyton dynamics. The second tested the feasibility of the flumes for the ex situ breeding of a threatened fish species, the European bullhead (Cottus gobio L.). The purpose of this paper is to raise awareness of this facility and make it available to researchers interested in eco-hydraulic studies in mountain environments.
Full article
(This article belongs to the Section New Sensors, New Technologies and Machine Learning in Water Sciences)
►▼
Show Figures

Figure 1
Open AccessArticle
Treatment of Novel Pigment Wastewater Using an AAO System: Tolerance, Start-Up and Operation, Toxicity Analysis, and Mitigation Strategies
by
Tongzhou Wang, Peipei Li, Yong Li, Lei Chen and Yanqiu Wang
Water 2026, 18(12), 1511; https://doi.org/10.3390/w18121511 - 19 Jun 2026
Abstract
The biological treatment risk associated with wastewater containing the novel pigment intermediate N,N′-(1,4-phenylene)bis(acetoacetamide) has not been previously characterized. This study systematically evaluated the tolerance and performance of a laboratory-scale anaerobic–anoxic–oxic (AAO) system subjected to progressively increasing loadings of high-concentration (COD > 10,000 mg·L
[...] Read more.
The biological treatment risk associated with wastewater containing the novel pigment intermediate N,N′-(1,4-phenylene)bis(acetoacetamide) has not been previously characterized. This study systematically evaluated the tolerance and performance of a laboratory-scale anaerobic–anoxic–oxic (AAO) system subjected to progressively increasing loadings of high-concentration (COD > 10,000 mg·L−1) wastewater. During a 39-day trial, the influent proportion was incrementally increased from 0.57% to 52.14% without system collapse. Complete microbial adaptation required approximately seven days. The anaerobic unit exhibited the highest sensitivity to shock loads, followed by the oxic unit, while the anoxic unit remained stable. GC-MS analysis confirmed the degradation of complex organic intermediates throughout the treatment stages, and TEST-based predictions indicated that the effluent exhibited lower predicted toxicity than the influent. Notably, cessation of mother liquor addition resulted in system self-recovery, further demonstrating robust shock resistance. This study provides the first experimental evidence of (i) unit-specific shock sensitivity (anaerobic > oxic > anoxic), (ii) a quantified adaptation period of approximately seven days, (iii) an operational threshold of 52.14% mother liquor without causing system collapse, and (iv) self-recovery following load cessation in an AAO system treating wastewater containing N,N′-(1,4-phenylene)bis(acetoacetamide). These findings extend previous AAO toxicity studies on industrial wastewater and present a practical, cost-effective mitigation strategy for full-scale applications.
Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
►▼
Show Figures

Figure 1
Open AccessArticle
Spatio-Temporal Comparison of Springs in the Southern Swiss Alps—Implications for Spring Conservation
by
Tania Pedimina, Simone Bontà and Stefanie von Fumetti
Water 2026, 18(12), 1510; https://doi.org/10.3390/w18121510 - 19 Jun 2026
Abstract
Springs are environmentally stable habitats that are refugia for specialized species. Springs at Monte Generoso, Monte Bar, and Monte Tamaro in the southern Swiss Alps were investigated to understand how they are affected by human activities and environmental changes. We conducted (a) a
[...] Read more.
Springs are environmentally stable habitats that are refugia for specialized species. Springs at Monte Generoso, Monte Bar, and Monte Tamaro in the southern Swiss Alps were investigated to understand how they are affected by human activities and environmental changes. We conducted (a) a temporal comparison of five springs at Monte Generoso, which were first sampled in 2011 and re-sampled in 2023 and (b) a spatial comparison of 19 springs of the three mountains. Physical and chemical parameters were measured, ecomorphology and anthropogenic impacts were evaluated, and macroinvertebrates were sampled. Springs at Monte Generoso changed along a temperature gradient. EPT-taxa shifted towards euryoecious taxa owing to environmental changes. The spatial comparison showed differences between the mountain summits driven by electrical conductivity and water temperature. These differences were mainly evident for Crenobia alpina and in the occurrence of Niphargus cf. thuringius in Bar and Tamaro as well as Drusus alpinus in Tamaro. Springs at Monte Generoso were the least diverse and exhibited the highest water temperature, possibly owing to the higher utilization pressure. Spring specialists were present even in heavily modified springs. This spatio-temporal analysis provided insights into the pressure on springs in the southern Swiss Alps, emphasizing the importance of a site-specific protection of these precious habitats.
Full article
(This article belongs to the Special Issue Biodiversity of Freshwater Ecosystems: Monitoring and Conservation, 2nd Edition)
►▼
Show Figures

Figure 1
Open AccessReview
Strategies for PPCP Removal from Sewage Sludge in a Circular Economy Context
by
Silvia González-Rojo, Alvaro Martínez-Sánchez and Xiomar Gómez
Water 2026, 18(12), 1509; https://doi.org/10.3390/w18121509 - 18 Jun 2026
Abstract
The transition to a circular economy requires the safe management of sewage sludge through nutrient and energy recovery. However, pharmaceuticals and personal care products (PPCPs) present a significant challenge. These compounds tend to accumulate in sludge via sorption, shifting the environmental burden from
[...] Read more.
The transition to a circular economy requires the safe management of sewage sludge through nutrient and energy recovery. However, pharmaceuticals and personal care products (PPCPs) present a significant challenge. These compounds tend to accumulate in sludge via sorption, shifting the environmental burden from the aqueous phase to the sludge. This manuscript provides a comprehensive review of the scientific literature on technical alternatives for valorizing sewage sludge and removing emerging contaminants. The study evaluates the limitations of conventional biological methods, such as anaerobic digestion and composting, which exhibit variable efficacy and are often insufficient to degrade some commonly used pharmaceuticals. On the contrary, thermal treatments (pyrolysis, gasification, and hydrothermal processes) are considered robust alternatives capable of achieving the high removal of chemical compounds. Furthermore, the article emphasizes the innovative potential of utilizing carbon-based byproducts (biochar and hydrochar) as adsorbents, catalysts, or soil amendment to enhance the removal of PPCPs within the treatment infrastructure itself. The integration of advanced thermal technologies is essential to mitigate the risks of contaminant transfer to the food chain and ensure a safe and sustainable nutrient cycle.
Full article
(This article belongs to the Special Issue Development of New Wastewater Treatments for the Efficient Removal of Micropollutants)
Open AccessArticle
Analysis of the Spatiotemporal Patterns of Water Conservation and Its Soil Driving Forces
by
Xiaolei Yan, Qianwen Zhan, Seping Dai and Chuanfu Zang
Water 2026, 18(12), 1508; https://doi.org/10.3390/w18121508 - 18 Jun 2026
Abstract
Soil is the principal physical space for water conservation (WC), so analyzing the driving forces of soil on WC is significant for studying WC services and integrated environmental management. Guangdong Province, a major economic province in China, was taken as a research case
[...] Read more.
Soil is the principal physical space for water conservation (WC), so analyzing the driving forces of soil on WC is significant for studying WC services and integrated environmental management. Guangdong Province, a major economic province in China, was taken as a research case to deeply analyze the spatiotemporal pattern of WC function from 2000 to 2020 with InVEST, and to reveal its soil driving forces using a classical mathematical statistics method. We found that, from 2000 to 2020, the WC functions in Guangdong Province exhibited significant spatiotemporal differences. High-value regions were mainly concentrated in the northern and western mountainous regions, while low-value areas were primarily in the Pearl River Delta. The total WC in Guangdong showed a fluctuating upward trend, with 10.71% of its area experiencing extremely significant improvement in the Pearl River Delta, followed by Northern Guangdong. Moreover, WC is influenced by the types and distribution areas of different soils. Red soil has the highest WC depth and volume, followed by paddy soil, while lateritic red soil has the lowest WC depth. Furthermore, soil components exhibited complex stratified relationships with precipitation-normalized WC (PNWC). Components characterized by cation exchange capacity (CEC), pH, and total exchangeable bases (TEB) were positively associated with PNWC, whereas aluminum saturation (ALSA) showed a negative association within the corresponding soil components. The findings provide an important scientific basis for the ecological governance of ecosystem WC functions and water resource management.
Full article
(This article belongs to the Special Issue Coupling Analysis of Ecosystem Functions and Water Resources in a Changing Environment)
►▼
Show Figures

Figure 1
Open AccessArticle
Trend of Debris Flow Disaster Development Triggered by Extreme Weather and Geological Events in Min County, Gansu Province, China
by
Lingzhi Xiang, Weimin Yang, Siqi Ma, Jingkai Qu, Yongjun Zhang, Feipeng Wan and Lingfu Yi
Water 2026, 18(12), 1507; https://doi.org/10.3390/w18121507 - 18 Jun 2026
Abstract
Min County experiences intense debris flow activity due to extreme weather and geological events. This study analyzes debris flow activity in Min County using GIS spatial analysis, time-series statistics, correlation analysis, periodic fitting, and field investigations across four event-based key periods (2002, 2012,
[...] Read more.
Min County experiences intense debris flow activity due to extreme weather and geological events. This study analyzes debris flow activity in Min County using GIS spatial analysis, time-series statistics, correlation analysis, periodic fitting, and field investigations across four event-based key periods (2002, 2012, 2013, and 2020). Long-term meteorological records (1951–2020) are introduced to support climatic trend analysis. Results indicate that stratigraphic lithology and fault tectonics control about 85–90% of the spatial distribution of debris flows, while extreme short-duration rainstorms trigger large-scale outbreaks and strong earthquakes further intensify activity. The high-occurrence cycle of debris flows (7–8 years) does not fully align with the annual wetness cycle (12 years). On a short time scale (years to decades), extreme earthquakes and rainstorms exert more significant impacts than normal precipitation patterns. This study preliminarily infers potential future peak periods of debris flows in Min County, with uncertainty from climate fluctuations and uncertain seismic events considered. The coupled mechanism of seismic weakening and rainfall triggering, together with lag-time characteristics, is revealed to support disaster prevention and mitigation.
Full article
(This article belongs to the Special Issue Water-Triggered Geo-Hazards in Underground and Geotechnical Engineering: Mechanisms, Early Warning and Sustainable Mitigation)
Open AccessArticle
Irrigation Water Management and Variability Drive Yield Outcomes in Peri-Urban Vegetable Systems: A Socio-Technical and Biophysical Analysis in Burkina Faso
by
Kpade O. L. Hounkpatin, Amadou Keita, Ebagnerin J. Tondoh, Djéneba Djamila Traoré, Nouroudine Morou Hamadou, Aymar Y. Bossa, Yacouba Yira, Jean Hounkpe, Traoré Hortense Kagambèga, Olayèmi Ursula Charlène Gaba, Djigbo Félicien Badou and Sarah Konaré
Water 2026, 18(12), 1506; https://doi.org/10.3390/w18121506 - 18 Jun 2026
Abstract
Understanding how irrigation water management shapes crop performance is critical for improving productivity and resource-use efficiency in peri-urban agriculture. This study investigated the socio-technical factors driving sprinkler system abandonment and assessed how irrigation water variability influences vegetable yield variability at two market gardening
[...] Read more.
Understanding how irrigation water management shapes crop performance is critical for improving productivity and resource-use efficiency in peri-urban agriculture. This study investigated the socio-technical factors driving sprinkler system abandonment and assessed how irrigation water variability influences vegetable yield variability at two market gardening sites (Bogdin and 14 Yaar) in Ouagadougou, Burkina Faso. Survey data from 50 farmers and field measurements of soil properties, irrigation water application, and lettuce yield were analyzed using descriptive statistics, Spearman correlations, and principal component analysis. More than 80% of farmers had ceased using the sprinkler system within two years of installation, 76% reported major equipment failures, and 70% expressed willingness to re-adopt an improved system. Irrigation dose and yield showed considerable variability across sites (CV = 20.9–42.3% and 36.4–44.0%, respectively). At 14 Yaar, irrigation dose was strongly associated with yield (r = 0.862, p = 0.006), indicating that uneven water application was a major constraint on productivity. At Bogdin, where irrigation was more uniform, no single soil or water variable dominated yield variability. Although soil fertility variables contributed to multivariate patterns, nutrient–yield correlations were not statistically significant under the available sample size, and their potential influence on yield requires confirmation with larger datasets. Overall, operational constraints, equipment failures, and inadequate support services contributed to sprinkler system abandonment, while variability in manual water application was associated with variability in crop productivity. These findings highlight the need for irrigation strategies that are both technically robust and adapted to farmers’ realities.
Full article
(This article belongs to the Section Soil and Water)
►▼
Show Figures

Figure 1
Open AccessReview
Membrane-Based Valorization of Sludge Digestates: Feedstock Characteristics, Pretreatment Effects, and Separation Performance
by
Anar Imamverdiyev, Zoltán Péter Jákói, Cecilia Hodúr and Sándor Beszédes
Water 2026, 18(12), 1505; https://doi.org/10.3390/w18121505 - 18 Jun 2026
Abstract
Sewage sludge management is increasingly shifting from a liability-focused “treat-and-dispose” approach toward resource recovery, where digestion residues and their liquid fractions are treated as secondary feedstocks for nutrient, water, and energy recovery. In Europe, the recast Urban Wastewater Treatment Directive strengthens performance and
[...] Read more.
Sewage sludge management is increasingly shifting from a liability-focused “treat-and-dispose” approach toward resource recovery, where digestion residues and their liquid fractions are treated as secondary feedstocks for nutrient, water, and energy recovery. In Europe, the recast Urban Wastewater Treatment Directive strengthens performance and monitoring requirements and reinforces the need for efficient sludge treatment and downstream valorization routes. This review synthesizes evidence on how pretreatment-induced changes in digestate properties translate into membrane performance outcomes and maps practical design implications for selecting pretreatment-membrane trains for nutrient recovery and reclaimed water production. Pressure-driven membrane methods (MF/UF/NF/RO), together with membrane distillation and electrodialysis, are central candidates for producing clarified water streams and concentrating nutrients; however, their performance is governed by digestate rheology, colloidal stability, and the composition of soluble microbial products and inorganic ions, which collectively shape fouling and scaling risks. Pretreatments such as thermal hydrolysis and microwave conditioning can modify floc structure and solubilize organics, with potential benefits for dewaterability and mass transfer, but can also shift particle size distributions toward fines and increase fouling propensity if not coupled with appropriate solid–liquid separation and conservative flux control. Emphasis is placed on mechanisms and operational trade-offs rather than single-point performance claims, highlighting where evidence is robust and where further comparability and full-scale validation remain necessary.
Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
Journal Menu
► ▼ Journal Menu-
- Water Home
- Aims & Scope
- Editorial Board
- Reviewer Board
- Topical Advisory Panel
- Early Career Editorial Board
- Instructions for Authors
- Special Issues
- Topics
- Sections
- Article Processing Charge
- Indexing & Archiving
- Editor’s Choice Articles
- Most Cited & Viewed
- Journal Statistics
- Journal History
- Journal Awards
- Society Collaborations
- Conferences
- Editorial Office
Journal Browser
► ▼ Journal BrowserHighly Accessed Articles
Latest Books
E-Mail Alert
News
Topics
Topic in
Environments, Hydrology, Sustainability, Water
Critical Issues in Groundwater Pollution Monitoring and Risk Warning
Topic Editors: Wenjing Zhang, Wenxia Wei, Huan Huan, Zhi Dou, Yuanzheng ZhaiDeadline: 30 June 2026
Topic in
Algorithms, Data, Earth, Geosciences, Mathematics, Land, Water, IJGI
Applications of Algorithms in Risk Assessment and Evaluation
Topic Editors: Yiding Bao, Qiang WeiDeadline: 31 July 2026
Topic in
Applied Sciences, Clean Technol., Energies, Membranes, Polymers, Sustainability, Water
New Advances in Membrane Technology and Its Contribution to Sustainability
Topic Editors: Patricia Luis Alconero, Bart Van der BruggenDeadline: 12 September 2026
Topic in
Agriculture, Climate, Energies, Land, Water
Energy, Environment and Climate Policy Analysis
Topic Editors: Xiaoqian Song, Jiajie LiDeadline: 30 September 2026
Conferences
Special Issues
Special Issue in
Water
Rethinking Wastewater: Microbial Solutions for a Sustainable Future
Guest Editors: Bharat Manna, Naresh SinghalDeadline: 20 June 2026
Special Issue in
Water
Biogeochemical Processes in Lakes, Ponds and Reservoirs of Urban Environments
Guest Editors: Yijun Xu, Xihua Wang, Siyue LiDeadline: 20 June 2026
Special Issue in
Water
Fate, Transport, Removal and Modeling of Pollutants in Water, 2nd Edition
Guest Editors: Nelson M. Anaya, Varun K. KasaraneniDeadline: 20 June 2026
Special Issue in
Water
Research on Microplastic Pollution in Water and Soil Environment
Guest Editors: Kai Cai, Taoze LiuDeadline: 20 June 2026






