Next Issue
Volume 18, April-1
Previous Issue
Volume 18, March-1
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
6.0
3.0
Journals
Water
Volume 18
Issue 6
water-logo

Journal Menu

► Journal Menu

Journal Browser

► Journal Browser
share announcement

Water, Volume 18, Issue 6 (March-2 2026) – 117 articles

Cover Story (view full-size image): This study quantifies the spatial–temporal variability of glaciers, shorelines, and outwash plains in Kaffiøyra, Svalbard, over four decades using cross-evaluated Landsat and Sentinel-2 imagery. Results reveal systematic retreat across all eight glaciers, with tidewater glaciers experiencing substantially greater terminus area loss compared to land-terminating glaciers. Shoreline erosion was most pronounced on shores exposed to southwesterly summer waves, while significant accretion occurred near the tidewater glacier terminus. Outwash changes remained insignificant despite substantial glacier retreat, indicating that these systems respond to different controls. A moderate negative correlation between glacier terminus area and summer temperatures enabled a simple diagnostic projection model, where locally extrapolated data proved more accurate than downscaled climate scenarios. View this paper
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
33 pages, 3319 KB  
Article
From Monitoring Data to Management Decisions: Causal Network Analysis of Water Quality Dynamics Using CEcBaN
by Sabrin Hilau, Yael Amitai and Ofir Tal
Water 2026, 18(6), 764; https://doi.org/10.3390/w18060764 - 23 Mar 2026
Viewed by 540
Abstract
Effective water resource management requires understanding the causal mechanisms driving water quality dynamics, yet extracting actionable insights from complex multivariate monitoring data remains a persistent challenge. This study presents CEcBaN (CCM-ECCM-Bayesian Networks), a decision-support tool that integrates Convergent Cross Mapping (CCM) for detecting [...] Read more.
Effective water resource management requires understanding the causal mechanisms driving water quality dynamics, yet extracting actionable insights from complex multivariate monitoring data remains a persistent challenge. This study presents CEcBaN (CCM-ECCM-Bayesian Networks), a decision-support tool that integrates Convergent Cross Mapping (CCM) for detecting dynamical coupling, Extended CCM (ECCM) for identifying temporal lags and causal directionality, and Bayesian network (BN) modeling for probabilistic scenario-based inference. The tool was designed to enable managers and researchers without programming expertise to reconstruct causal networks from routine monitoring data, distinguish direct from indirect effects, and evaluate intervention scenarios. CEcBaN was validated using four synthetic datasets with known causal structures, achieving superior specificity (0.83) and edge count accuracy (25% error) compared to Transfer Entropy (0.47 specificity, 139% error), Granger causality (0.82, 39% error), and the PC algorithm (0.83, 46% error). Application to Lake Kinneret, Israel, demonstrated the tool’s utility across three water quality challenges: (1) nitrogen cycling, where the nitrification pathway was reconstructed and seasonal stratification was identified as a key modulator (accuracy 0.931); (2) thermal dynamics, where a transition from atmosphere-driven to internally regulated heat transfer during stratification was revealed (2.1-fold increase in coupling strength); and (3) cyanobacterial bloom prediction, where prior phytoplankton community composition provided a 4–6-week early warning window (accuracy 0.846). CEcBaN advances causal inference in water resource management by making these analytical methods accessible through an intuitive interface. Full article
(This article belongs to the Special Issue Management and Sustainable Control of Harmful Algal Blooms)
►▼ Show Figures

Figure 1

18 pages, 4096 KB  
Article
Corrosion Characteristics of Iron Pipe in Reclaimed Water Disinfected by UV/NaClO
by Cuimin Feng, Siyu Li, Dandan Liu, Tong Wei and Yadong Wang
Water 2026, 18(6), 763; https://doi.org/10.3390/w18060763 - 23 Mar 2026
Viewed by 372
Abstract
The use of reclaimed water is a crucial strategy for water conservation. However, the quality of reclaimed water may induce corrosion in pipelines. Although UV (Ultraviolet) irradiation is a highly effective physical disinfection method that requires no chemical additives, it must be used [...] Read more.
The use of reclaimed water is a crucial strategy for water conservation. However, the quality of reclaimed water may induce corrosion in pipelines. Although UV (Ultraviolet) irradiation is a highly effective physical disinfection method that requires no chemical additives, it must be used in conjunction with NaClO (Sodium hypochlorite) disinfection because UV alone cannot provide continuous control of bacterial growth. This study monitored the concentrations of Cl− and SO42− in water samples collected from an annular biofilm coupon reactor, as well as the corrosion rate of cast iron coupons, to explore the corrosion characteristics of reclaimed water pipelines under different disinfection modes. The results showed that, when using NaClO as the sole disinfectant, the corrosion rate of the pipeline was the lowest at a NaClO dosage of 7 mg/L (corrosion rate: 0.85 mm/a at 72 h). For the UV-NaClO-combined disinfection, the optimal parameters were a UV dose of 120 mJ/cm2 and a NaClO dosage of 5 mg/L, with a minimum corrosion rate of 0.62 mm/a at 72 h. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses revealed that a protective CaCO3 layer forms on the pipe surface in the early corrosion stage, which effectively protects the metal pipeline. This study innovatively clarifies the synergistic effect of UV and NaClO on pipeline corrosion and identifies the optimal disinfection parameters, filling the research gap in the correlation between combined disinfection and cast iron pipe corrosion in reclaimed water systems. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
►▼ Show Figures

Figure 1

24 pages, 6753 KB  
Article
Generalised Machine Learning Model for Prediction of Heavy Metals in Stormwater
by Łukasz Bąk, Jarosław Górski and Bartosz Szeląg
Water 2026, 18(6), 762; https://doi.org/10.3390/w18060762 - 23 Mar 2026
Viewed by 449
Abstract
The dynamics of the processes shaping the quality of rainwater discharged by sewer systems is very complex. The use of hydrodynamic models to simulate surface runoff and the dynamics of changes in pollutants, including heavy metal (HM) concentrations, requires the collection of a [...] Read more.
The dynamics of the processes shaping the quality of rainwater discharged by sewer systems is very complex. The use of hydrodynamic models to simulate surface runoff and the dynamics of changes in pollutants, including heavy metal (HM) concentrations, requires the collection of a lot of data that is difficult to obtain, and model calibration is complex and time-consuming. This paper presents a machine learning model and investigates the possibility of applying data mining methods to simulate changes in the concentrations of selected heavy metals (Ni, Cu, Cr, Zn and Pb) based on rainwater quality studies conducted in three urban catchments located in Kielce, southern Poland, with the aim of developing a model with broader applicability. Simulations of HM content in rainwater were performed using regression and classification trees (RF), neural networks (MLP) and support vector machines (SVMs). The MLP (MAPE ≤ 21.6) and SVM (MAPE ≤ 23.5) methods were shown to have the highest accuracy in simulating HM content. These models produced satisfactory simulation results based on rainfall amount and meteorological conditions, and they had relatively simple model structures and short simulation time. The study demonstrated that the proposed approach provides a transferable tool for estimating HM content in rainwater based on air quality, expressed in terms of visibility, and the type of catchment development. Full article
(This article belongs to the Special Issue Urban Stormwater Control, Utilization and Treatment, 2nd Edition)
►▼ Show Figures

Figure 1

28 pages, 3729 KB  
Article
Integrated Assessment of Water Resource Carrying Capacity: Dynamics, Obstacles, Coordination and Driving Mechanisms in the Gansu Section of the Yellow River Basin, China
by Jianrong Xiao, Jinxia Zhang, Guohua He, Haiyan Li, Liangliang Du, Runheng Yang, Meng Yin, Pengliang Tian, Yangang Yang, Qingzhuo Li, Xi Wei and Yingru Xie
Water 2026, 18(6), 761; https://doi.org/10.3390/w18060761 - 23 Mar 2026
Viewed by 465
Abstract
Accurately assessing dynamic water resource carrying capacity (WRCC) is essential and challenging, particularly in regions like the Gansu sections of the Yellow River Basin (GSYRB), a core water source protection zone in the arid northwest of China, due to its pressing challenge of [...] Read more.
Accurately assessing dynamic water resource carrying capacity (WRCC) is essential and challenging, particularly in regions like the Gansu sections of the Yellow River Basin (GSYRB), a core water source protection zone in the arid northwest of China, due to its pressing challenge of balancing water resources for socioeconomic needs and ecological security. This study proposes a novel integrated computational assessment framework named SD-VIKOR to address the complexities arising from nonlinear interactions within the “water resources–socioeconomic–ecological environment” (W–S–E) system. The core of this framework is the tight coupling of a system dynamics (SD) simulation model with a VIKOR multi-criteria evaluation module, where indicator weights are objectively–subjectively determined via an Analytic Hierarchy Process (AHP)–entropy weight method. This integrated SD-VIKOR engine enables dynamic, scenario-based WRCC trajectory simulation. To move beyond simulation and enable mechanistic insight, the framework further incorporates a diagnostic suite: a Geodetector module quantifies dominant drivers and their interactions; an obstacle degree model pinpoints key limiting factors; and a coupling coordination degree model evaluates subsystem synergies. Together, they form a closed-loop “dynamic simulation → multi-criteria assessment → driving mechanism analysis and constraint diagnosis → subsystem coordination analysis” workflow. Applied to the GSYRB from 2012 to 2030 under five development scenarios, the framework demonstrated high efficacy. It successfully captured path-dependent WRCC evolution, revealing that the ecological-priority scenario (B2), which shifts system drivers from economic-scale expansion to resource-efficiency and environmental governance, yielded optimal WRCC and the highest system coordination. In contrast, business-as-usual and single-minded economic expansion scenarios underperformed. Six key obstacle factors were quantitatively identified, linking WRCC constraints to natural endowments, economic patterns, and domestic demand. The results reveal pronounced spatial–temporal heterogeneity in WRCC across the GSYRB, with socioeconomic development, water resource use efficiency, and ecological conditions acting as the primary joint drivers of WRCC evolution. Critically, several key indicators are identified as persistent constraints on regional water sustainability. In contrast to conventional static evaluations, the integrated framework captures the complex dynamics and multi-subsystem interactions governing WRCC, offering a more robust diagnostic of resource–environment systems. These insights provide a transferable analytical basis for designing sustainable water management strategies in arid river basins. Full article
(This article belongs to the Section Hydrology)
►▼ Show Figures

Figure 1

22 pages, 4246 KB  
Article
Isotopic Composition of Precipitation and Its Role in Forest Hydrology Under Climate Change: Insights from Slovenian Lowland Forests
by Katja Koren Pepelnik, Mitja Janža, Matjaž Čater, Barbara Čenčur Curk and Polona Vreča
Water 2026, 18(6), 760; https://doi.org/10.3390/w18060760 - 23 Mar 2026
Cited by 1 | Viewed by 452
Abstract
Monitoring of stable isotopes in throughfall (δ18O, δ2H) and meteorological parameters is a valuable tool for researching forest hydrology, particularly during extreme events like droughts and floods. This study presents the first systematic analysis of air temperature and [...] Read more.
Monitoring of stable isotopes in throughfall (δ18O, δ2H) and meteorological parameters is a valuable tool for researching forest hydrology, particularly during extreme events like droughts and floods. This study presents the first systematic analysis of air temperature and precipitation changes over the past 65 years in two Slovenian lowland forests: Murska šuma and Krakovski gozd, in combination with isotopic composition research of throughfall. The observed rising air temperatures and altered precipitation patterns are reflected in the isotopic composition of throughfall. Over the last 65 years, air temperature has increased by approximately 2.5 °C. Although total annual precipitation amounts have remained relatively stable, in the last 35 years there is a notable decrease in precipitation in growing season and an increase during the dormant season, influenced by air masses of Mediterranean origin. Extreme drought in 2022 and flood in 2023 are confirmed by the Standardized Precipitation Index and isotopic variations in throughfall due to fractionation processes. Annual variability appears as seasonal changes, with sine-curve amplitudes of 3.71‰ in Krakovski gozd and 3.61‰ in Murska šuma. Together with the Local Meteoric Water Lines, these patterns support estimates of groundwater mean residence time and the origin of water used by trees. Full article
(This article belongs to the Special Issue Application of Isotope Geochemistry in Hydrological Research)
►▼ Show Figures

Figure 1

17 pages, 3255 KB  
Article
Enhanced Photocatalytic Degradation of Tetracycline over Alcohol-Assisted Bi2O3/TiO2 Composite Heterojunction Under UV Irradiation
by Ruiwei Liu, Shuai Zhang, Qiong Huang, Yucen Liu, Liujun Zhou, Zisu Yang, Jiaxin Shan, Xi Tong and Hong Yang
Water 2026, 18(6), 759; https://doi.org/10.3390/w18060759 - 23 Mar 2026
Viewed by 466
Abstract
The widespread presence of antibiotic residues in aquatic environments poses severe ecological risks. While photocatalytic oxidation offers a promising, eco-friendly remediation technology, developing stable and high-efficiency photocatalysts remains a significant challenge. This study investigates the synthesis of Bi2O3/TiO2 [...] Read more.
The widespread presence of antibiotic residues in aquatic environments poses severe ecological risks. While photocatalytic oxidation offers a promising, eco-friendly remediation technology, developing stable and high-efficiency photocatalysts remains a significant challenge. This study investigates the synthesis of Bi2O3/TiO2 heterojunction with tailored morphological structures to enhance the degradation of tetracycline (TC). A series of Bi2O3/TiO2 photocatalysts were prepared via a solvothermal method using mixed alcohol solvents (ethylene glycol and ethanol) to regulate morphology. Comprehensive characterization was performed using XRD, BET, TEM, XPS, UV-Vis, and PL spectroscopy. Photocatalytic activity was evaluated by monitoring TC removal efficiency under light irradiation. The optimized catalyst of BT5-EG3 (n(Bi)/n(Ti) = 0.05; V(EG):V(ethanol) = 1:3) achieved the highest TC conversion of 93.9% within 120 min. This superior performance is attributed to a large specific surface area, abundant lattice oxygen, and a narrowed band gap of 2.52 eV, which significantly promoted the spatial separation of photogenerated charge carriers and suppressed their ultrafast recombination. The reaction followed pseudo-first-order kinetics, and the catalyst demonstrated excellent stability, providing a robust strategy for treating antibiotic-polluted water. Full article
(This article belongs to the Special Issue Water Treatment Technology for Emerging Contaminants, 2nd Edition)
►▼ Show Figures

Figure 1

20 pages, 18170 KB  
Article
Multi-Factor Air–Sea Heat Exchange Study on the Thermal Discharge Diffusion at Coastal Nuclear Power Plants: Sensitivity and Contribution Analysis
by Kezheng Lei, Fangfang Cheng, Tuantuan Liu, Ruini Liu and Aiming Zhang
Water 2026, 18(6), 758; https://doi.org/10.3390/w18060758 - 23 Mar 2026
Viewed by 379
Abstract
Solar radiation, longwave radiation, sensible heat flux, and latent heat flux constitute the primary forms of air–sea heat exchange, serving as crucial computational parameters in numerical simulations of thermal discharge. This study investigates a coastal nuclear power plant and employs a modified Morris [...] Read more.
Solar radiation, longwave radiation, sensible heat flux, and latent heat flux constitute the primary forms of air–sea heat exchange, serving as crucial computational parameters in numerical simulations of thermal discharge. This study investigates a coastal nuclear power plant and employs a modified Morris screening method to quantitatively assess the contribution rates of various air–sea heat exchange processes to the spatial distribution of temperature rise under different operating conditions. The results indicate that the influence of air–sea heat exchange processes on the thermal discharge envelope exhibits a nonlinear pattern. The individual parameter sensitivity of shortwave radiation, sensible heat flux and latent heat flux is higher in the low temperature rise region (∆T ≥ 1 °C) than in the high temperature rise region (∆T ≥ 4 °C), with the individual parameter sensitivities of longwave radiation and latent heat flux displaying distinct threshold effects. The dominant heat exchange mechanisms vary across temperature rise regions: longwave radiation predominates in the high temperature rise region (∆T ≥ 4 °C), contributing approximately 74.71%, whereas latent and sensible heat fluxes dominate in the low temperature rise region (∆T ≥ 1 °C), accounting for a combined contribution of about 88.58%. These findings provide a scientific basis for model simplification and targeted parameterization. Full article
(This article belongs to the Section Oceans and Coastal Zones)
►▼ Show Figures

Figure 1

15 pages, 3549 KB  
Article
Application and Comparison of Two Transformer-Based Deep Learning Models in Short-Term Precipitation Nowcasting
by Chuhan Lu and Qilong Pan
Water 2026, 18(6), 757; https://doi.org/10.3390/w18060757 - 23 Mar 2026
Viewed by 533
Abstract
Against the background of intensifying global climate change, extreme precipitation events have become increasingly frequent. Improving the accuracy of short-term precipitation nowcasting is therefore essential for disaster prevention and mitigation. Traditional numerical weather prediction (NWP) approaches are constrained by computational latency and errors [...] Read more.
Against the background of intensifying global climate change, extreme precipitation events have become increasingly frequent. Improving the accuracy of short-term precipitation nowcasting is therefore essential for disaster prevention and mitigation. Traditional numerical weather prediction (NWP) approaches are constrained by computational latency and errors arising from physical parameterizations, making it difficult to satisfy real-time forecasting requirements at high spatiotemporal resolution. Using the SEVIR dataset, this study conducts a systematic comparison of two Transformer-based deep learning models—Earthformer and LLMDiff—for short-term extreme precipitation nowcasting. Model performance is evaluated using the Critical Success Index (CSI), Probability of Detection (POD), and Success Ratio (SUCR). Results indicate that, for 0–30 min lead times, Earthformer more efficiently captures both local and long-range spatiotemporal dependencies via its Cuboid Attention mechanism and shows a slight advantage for low-intensity precipitation. As the lead time extends to 60 min, LLMDiff demonstrates stronger longer-horizon skill due to its diffusion-based probabilistic modeling and a frozen large language model (LLM) module, which enhance the representation of uncertainty and longer-term evolution of precipitation systems. However, LLMDiff tends to produce a higher false-alarm rate. Overall, Earthformer is better suited for rapid early warning of light precipitation, whereas LLMDiff is more appropriate for high-accuracy nowcasting of heavy precipitation, offering useful insights for intelligent forecasting of extreme weather. Full article
(This article belongs to the Special Issue Analysis of Extreme Precipitation Under Climate Change, 2nd Edition)
►▼ Show Figures

Figure 1

21 pages, 5520 KB  
Article
Comparison of Microclimate and Soil Hydrology in the Spruce Stand and Buffer Zone of a Fir–Beech Primeval Forest Across Years with Various Drought Risks
by Zuzana Greštiak Oravcová, Paulína Nalevanková, Miriam Hanzelová, Michal Bošeľa and Jaroslav Vido
Water 2026, 18(6), 756; https://doi.org/10.3390/w18060756 - 23 Mar 2026
Viewed by 393
Abstract
Climate change leads to less water in forest ecosystems and higher evapotranspiration during the growing season, increasing the risk of drought. This study evaluates microclimate and soil hydrology at two different sites in the Dobroč Primeval Forest (National Nature Reserve, NATURA 2000): a [...] Read more.
Climate change leads to less water in forest ecosystems and higher evapotranspiration during the growing season, increasing the risk of drought. This study evaluates microclimate and soil hydrology at two different sites in the Dobroč Primeval Forest (National Nature Reserve, NATURA 2000): a near-natural fir–beech buffer zone and a managed Norway spruce monoculture. Measurements cover two hydrological years with very different climatic conditions. The Climatic Water Balance (CWB) was used to assess precipitation deficit, and soil moisture dynamics were simulated with the GLOBAL mathematical model. In 2021, precipitation was 223.7 mm below the long-term average, and the cumulative CWB deficit from March to September was 224 mm. Drought risk peaked in summer 2021. The spruce stand’s A/B horizon was 197 days below the point of decreased availability (PDA), compared to 179 days in the beech buffer zone. Drought moved through the soil profile with a 3–4-day lag between horizons at both sites. Results confirm that Norway spruce monocultures are more drought-vulnerable than near-natural beech stands under identical conditions, supporting active forest conversion in Central European mountain regions. Full article
(This article belongs to the Section Ecohydrology)
►▼ Show Figures

Figure 1

23 pages, 7135 KB  
Article
Smart Farming Technologies for Groundwater Conservation in Transboundary Aquifers of Northwestern México
by Alfredo Granados-Olivas, Luis C. Bravo-Peña, Víctor M. Salas-Aguilar, Christopher Brown, Alfonso Gandara-Ruiz, Víctor H. Esquivel-Ceballos, Felipe A. Vázquez-Gálvez, Richard Heerema, Josiah M. Heyman, Ismael Aguilar-Benitez, Alexander Fernald, Joam M. Rincón-Zuloaga, William L. Hargrove and Luis C. Alatorre-Cejudo
Water 2026, 18(6), 755; https://doi.org/10.3390/w18060755 - 23 Mar 2026
Viewed by 728
Abstract
This study evaluated the performance of a smart farming technology (SFT) and a climate-smart agriculture (CSA) approach for improving irrigation management in pecan (Carya illinoinensis) orchards in México through soil moisture monitoring, evapotranspiration estimation, and real-time data integration. Continuous monitoring allowed [...] Read more.
This study evaluated the performance of a smart farming technology (SFT) and a climate-smart agriculture (CSA) approach for improving irrigation management in pecan (Carya illinoinensis) orchards in México through soil moisture monitoring, evapotranspiration estimation, and real-time data integration. Continuous monitoring allowed irrigation to be maintained at field capacity, preventing plant stress while avoiding total soil saturation or permanent wilting point. Calibration of soil moisture sensors showed a very strong correlation (R2 = 0.99) between sensor reverse voltage and volumetric soil water content in predominant sandy loam soils, confirming the reliability of the monitoring system for irrigation scheduling. Seasonal analysis of reference evapotranspiration (ETo) and crop evapotranspiration (ETc) revealed increasing atmospheric water demand during summer months, with crop coefficient (Kc) values ranging from approximately 0.3 during dormancy to 1.0–1.3 during peak vegetative growth. After five years of field implementation of the technology, results showed water savings exceeding 50% compared with traditional flood irrigation practices. The optimized irrigation schedule reduced total seasonal irrigation depth from 216 cm to 128 cm, representing a 59% reduction in applied water while maintaining adequate soil moisture conditions for crop development at field capacity (FC). These results highlight the potential of integrating sensor-based monitoring, evapotranspiration modeling, and IoT platforms to enhance water-use efficiency and support sustainable pecan production under increasing climate variability. Full article
(This article belongs to the Special Issue Working Across Borders to Address Water Scarcity)
►▼ Show Figures

Figure 1

33 pages, 18598 KB  
Article
Seasonal Dynamics of Surface Water–Groundwater Interactions in the Niya River Basin, Northwest China: Insights from Hydrochemistry and Stable Isotopes
by Shaoqi Shi, Sheng Li, Yanyan Ge, Feilong Jie, Tianchao Liu and Tong Li
Water 2026, 18(6), 754; https://doi.org/10.3390/w18060754 - 23 Mar 2026
Viewed by 470
Abstract
Surface water–groundwater interactions within oasis–desert ecotones of arid regions play a pivotal role in sustaining regional water security and ecological stability. Taking the Niya River Basin in Xinjiang, Northwest China, as a representative inland watershed, this study systematically elucidates the mechanisms and seasonal [...] Read more.
Surface water–groundwater interactions within oasis–desert ecotones of arid regions play a pivotal role in sustaining regional water security and ecological stability. Taking the Niya River Basin in Xinjiang, Northwest China, as a representative inland watershed, this study systematically elucidates the mechanisms and seasonal dynamics of surface water–groundwater coupling under the combined influences of natural processes and anthropogenic activities. A total of 68 surface water and groundwater samples were collected during the dry, normal, and wet hydrological periods. Integrated hydrochemical characterization, mineral saturation index analysis, and stable isotope (δ2H and δ18O) mass balance modeling were employed to quantify recharge contributions and unravel hydrogeochemical evolution pathways. Results indicate that the waters in the study area are predominantly brackish to saline, with consistent dominant ionic assemblages (SO42− and Na+) across all hydrological periods, highlighting evaporite dissolution as the primary control on solute composition. Hydrochemical evolution is jointly regulated by evaporation concentration, water–rock interactions, and cation exchange processes. Surface water chemistry reflects the combined effects of silicate weathering and evaporite dissolution, whereas groundwater chemistry is mainly governed by evaporite dissolution coupled with pronounced cation exchange. Stable isotope signatures reveal substantial secondary evaporation of regional precipitation prior to recharge. Frequent bidirectional recharge between surface water and groundwater was observed, exhibiting distinct seasonal transitions. During the dry period, groundwater provides significant baseflow support to surface water (48.6% in the oasis zone and 54.3% in the desert zone). In the normal period, recharge direction reverses, with surface water becoming the dominant source of groundwater recharge (99.0% in the oasis zone and 76.6% in the desert zone). In the wet period, spatial heterogeneity becomes evident: surface water continues to dominate groundwater recharge in the oasis zone (92.7%), whereas groundwater recharge to surface water prevails in the desert zone (50.5%). This study identifies a seasonally dynamic “discharge–infiltration–zonal regulation” bidirectional recharge pattern in arid inland river systems. The findings advance the mechanistic understanding of hydrological connectivity reconstruction within oasis–desert ecotones and provide a scientific basis for optimized regional water resource allocation and groundwater salinization risk mitigation. Full article
(This article belongs to the Section Water Quality and Contamination)
►▼ Show Figures

Figure 1

17 pages, 1493 KB  
Article
Slope-Controlled Partitioning of Vertical and Lateral Solute Transport Pathways Revealed by Inclined Leaching Experiments
by Xiaoli Zhou, Jiakun Dong, Buxu Sun, Ziyi Yang, Xiaoping Sun and Yu Shen
Water 2026, 18(6), 753; https://doi.org/10.3390/w18060753 - 23 Mar 2026
Viewed by 320
Abstract
Using perfluorooctanoic acid (PFOA) as a representative highly mobile solute to isolate hydrological controls, we investigated how slope influences the partitioning of vertical and lateral transport pathways. While vertical percolation has been widely examined using conventional column leaching tests, lateral transport driven by [...] Read more.
Using perfluorooctanoic acid (PFOA) as a representative highly mobile solute to isolate hydrological controls, we investigated how slope influences the partitioning of vertical and lateral transport pathways. While vertical percolation has been widely examined using conventional column leaching tests, lateral transport driven by topographic gradients remain insufficiently quantified under controlled conditions. Here, laboratory-scale inclined leaching experiments were conducted to resolve the distribution of solute transport among vertical leachate, lateral runoff, and solid-phase retention under systematically varied slope angles (0°, 4°, 9°, and 20°), flow regimes, and leaching volumes. Results show that solute migration shifted from vertical-dominated transport under flat conditions (91% at 0°) to lateral-dominated export at moderate slopes, with lateral pathways accounting for up to 75% of the recovered mass at 9°. This pathway shift was well described by an exponential partitioning model, f1(α) = fmax (1 − e−kα), where fmax = 0.80 and k = 0.34°−1 (R2 = 0.97), indicating a critical crossover threshold at approximately 4° slope. Flow regime interacted with slope angle to modulate lateral transport efficiency: slower flow enhanced lateral export at moderate slopes, whereas faster flow promoted peak lateral transport under steeper conditions. In contrast, solid-phase retention remained consistently low (5–9%) across all treatments, indicating that the observed redistribution patterns were primarily governed by hydrological pathway partitioning rather than sorption processes. These results demonstrate that even modest topographic gradients can fundamentally alter solute transport pathways in sloped soils. The slope-dependent pathway partitioning framework developed here provides a process-based basis for incorporating lateral transport into hillslope hydrological models and for improving assessments of contaminant redistribution in both managed and natural landscapes. Full article
(This article belongs to the Section Hydrogeology)
►▼ Show Figures

Graphical abstract

19 pages, 1604 KB  
Article
Ecological Selection of Anammox Bacteria Driven by Endogenous Carbon in a Low-Oxygen SBR Biofilm System Without External Carbon Addition
by Yanqing He, Yufeng Zheng, Yaqiong Gu, Qikang Zhang, Yan Wei, Yinan Bu and Bin Ma
Water 2026, 18(6), 752; https://doi.org/10.3390/w18060752 - 23 Mar 2026
Viewed by 345
Abstract
This study investigated the ecological selection and enrichment of anaerobic ammonium-oxidizing bacteria (AnAOB) driven by endogenous carbon cycling in a low-oxygen SBR biofilm system without external carbon addition. The system was operated using dried biofilm inoculation, continuous low oxygen (DO < 0.1 mg/L), [...] Read more.
This study investigated the ecological selection and enrichment of anaerobic ammonium-oxidizing bacteria (AnAOB) driven by endogenous carbon cycling in a low-oxygen SBR biofilm system without external carbon addition. The system was operated using dried biofilm inoculation, continuous low oxygen (DO < 0.1 mg/L), and complete drainage. After 117 days, AnAOB were enriched to 8.14% relative abundance and became the dominant functional group. At an influent total nitrogen (TN) of 25 mg/L, the average effluent TN and NH4+-N were 6.37 and 3.75 mg/L, respectively, corresponding to a TN removal efficiency of 75% and meeting the Class A discharge standard. Metagenomic and metatranscriptomic analyses revealed that anammox was the primary nitrogen removal pathway, with nitrite supplied through partial nitrification and endogenous partial denitrification. Higher expression of nitrate reductase genes than of nitrite reductase genes favored nitrite accumulation through endogenous partial denitrification, thereby creating a self-sustaining internal cycle between nitrate reduction and anammox. Extracellular polymeric substances (EPS) served as the key internal carbon source driving this process. This ecological regulation strategy provides an energy-efficient and stable strategy for mainstream low C/N municipal wastewater treatment without external carbon addition. Full article
(This article belongs to the Special Issue Biological Nitrogen Removal in the Multi-Omics Era: Coupling Anammox with Microbial-Mineral Synergy)
►▼ Show Figures

Figure 1

35 pages, 2690 KB  
Systematic Review
Integrated Sediment Yield Estimation and Control in Erosion-Prone Watersheds: A Systematic Review of Models, Strategies, and Emerging Technologies
by Kevin Paolo V. Robles, Cris Edward F. Monjardin, Jerose G. Solmerin and Gerald Christian E. Pugat
Water 2026, 18(6), 751; https://doi.org/10.3390/w18060751 - 23 Mar 2026
Viewed by 659
Abstract
Sediment yield remains a major challenge in erosion-prone watersheds because it affects reservoir capacity, water quality, hydraulic infrastructure, and ecological stability. Although numerous studies have examined sediment yield estimation and sediment control, these topics are often treated separately, limiting the development of integrated [...] Read more.
Sediment yield remains a major challenge in erosion-prone watersheds because it affects reservoir capacity, water quality, hydraulic infrastructure, and ecological stability. Although numerous studies have examined sediment yield estimation and sediment control, these topics are often treated separately, limiting the development of integrated watershed management strategies. Unlike many existing sediment yield review papers that focus primarily on predictive models, erosion processes, or management measures in isolation, this study provides an integrated synthesis of sediment yield estimation methods and sediment control strategies within a single watershed management framework for erosion-prone environments. The review covers empirical models, traditional sampling, physically based models, and emerging data-driven tools such as artificial intelligence, machine learning, remote sensing, and sensor-based monitoring, alongside structural, vegetative, and adaptive sediment control measures. The reviewed literature indicates three major trends: increasing integration of GIS and remote sensing with conventional models, wider use of process-based models for scenario analysis, and rapid growth of AI-based methods for real-time and nonlinear prediction. The findings further show that no single estimation or control strategy is universally applicable; performance depends strongly on watershed scale, sediment connectivity, land use, climatic regime, and data availability. Overall, the review highlights the need for integrated, adaptive, and site-specific sediment management frameworks that combine predictive modeling, monitoring technologies, and practical control interventions to improve long-term watershed resilience. Full article
(This article belongs to the Special Issue Sediment Pollution: Methods, Processes and Remediation Technologies)
►▼ Show Figures

Figure 1

13 pages, 3488 KB  
Article
Formation, Storage and Reactivation of Aerobic Granular Sludge in Real Dyeing Wastewater
by Tao Guo, Nengbin Tang, Rongwu Mei and Jun Li
Water 2026, 18(6), 750; https://doi.org/10.3390/w18060750 - 23 Mar 2026
Viewed by 404
Abstract
This study aimed to evaluate the process of formation, storage and reactivation of aerobic granular sludge (AGS) in real dyeing wastewater. An SBR was employed for the AGS operation, and the results showed that AGS could form in the SBR within 30 days [...] Read more.
This study aimed to evaluate the process of formation, storage and reactivation of aerobic granular sludge (AGS) in real dyeing wastewater. An SBR was employed for the AGS operation, and the results showed that AGS could form in the SBR within 30 days and was reactivated in 20 days after 300 days of storage. The nutrient removal efficiency remained stable after formation and reactivation. Metal ions (Fe and Ca) and inorganic matter from raw wastewater not only improved AGS formation efficiency but also ensured its structural stability during long-term storage. The initially formed AGS was enriched with Fe and Ca. However, during storage, Fe deposited on the AGS surface was lost due to iron-reducing bacteria (Shewanella). In the reactivated AGS, Ca deposited in the core became dominant. This work fully describes the formation, storage, and reactivation of AGS in real dyeing wastewater and reveals the stabilization mechanism of Ca- and Fe-rich AGS during long-term storage. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
►▼ Show Figures

Figure 1

31 pages, 5309 KB  
Article
Analysis of Embankment Seepage Responses Based on Physics-Informed Neural Networks Surrogate Model
by Cekai Fu, Qiang Wang, Chenfei Shao, Yanxin Xu and Sen Zheng
Water 2026, 18(6), 749; https://doi.org/10.3390/w18060749 - 23 Mar 2026
Viewed by 433
Abstract
Accurate and efficient analysis of embankment seepage is of vital importance for scientific assessment of embankment safety. Conventional numerical simulation techniques for embankment seepage analysis suffer from high computational cost and low efficiency. To address this issue, this paper proposes an embankment seepage [...] Read more.
Accurate and efficient analysis of embankment seepage is of vital importance for scientific assessment of embankment safety. Conventional numerical simulation techniques for embankment seepage analysis suffer from high computational cost and low efficiency. To address this issue, this paper proposes an embankment seepage response analysis method based on physical information neural network (PINN). Initially, this method considering the fluid–solid coupling and spatial variability of soil parameters of the embankment. Consequently, a numerical simulation method was developed using the finite difference method to analyze the seepage response. On this basis, a neural network loss function for the surrogate model is introduced by integrating the governing equations for fluid–solid coupling of embankments with boundary conditions. This integration incorporates physical restrictions into the seepage analysis, hence improving its interpretability. Furthermore, a feature sequence is derived from the soil parameter field via a Variational Autoencoder (VAE) to diminish input dimensionality and improve training accuracy. The feature sequence and hydraulic loading function as the model input, while the output is the piezometric head obtained from the pore water pressure. The PINN model is trained by numerical simulation results to establish the surrogate model for seepage responses analysis. A case study on the practical embankment engineering is employed to confirm the feasibility and efficacy of the proposed strategy. Comparative tests demonstrate that the PINN surrogate model markedly enhances computational accuracy relative to conventional baseline models. Overall, this approach offers a trustworthy and effective method for rapid and accurate assessment of embankment seepage characteristics. Full article
(This article belongs to the Special Issue New Aseismic Technology and Methods in Hydraulic Structures and Geotechnical Engineering)
►▼ Show Figures

Figure 1

22 pages, 2901 KB  
Article
Investigation of the Effect of Plasma Discharge on Harmful Microorganisms in Water
by Askar Abdykadyrov
Water 2026, 18(6), 747; https://doi.org/10.3390/w18060747 - 23 Mar 2026
Viewed by 352
Abstract
Microbiological contamination of drinking water remains a significant public health concern worldwide, necessitating the development of efficient and environmentally friendly disinfection technologies. This study investigated the effectiveness and physicochemical mechanisms of water treatment using high-frequency electrical discharge plasma. Experimental research was conducted employing [...] Read more.
Microbiological contamination of drinking water remains a significant public health concern worldwide, necessitating the development of efficient and environmentally friendly disinfection technologies. This study investigated the effectiveness and physicochemical mechanisms of water treatment using high-frequency electrical discharge plasma. Experimental research was conducted employing a laboratory dielectric barrier discharge reactor operating at 10–30 kHz and 10–25 kV, with treatment durations ranging from 5 to 20 min. Plasma exposure resulted in pronounced physicochemical changes in the aqueous medium, including a decrease in pH from 7.1–7.3 to 5.4–6.0 and an increase in electrical conductivity from 280–340 µS/cm to 480–620 µS/cm. The formation of reactive oxygen species, including hydroxyl radicals, ozone, and hydrogen peroxide, was confirmed, with hydrogen peroxide concentrations varying between 0.35 and 1.20 mg/L. Microbiological analysis demonstrated a reduction in microbial concentration from approximately 105–106 CFU/mL to 102–103 CFU/mL, corresponding to 3–4 log inactivation. The results indicated that microbial reduction was strongly associated with the generation of reactive species and treatment duration. Energy density within the range of 0.3–1.2 kWh/m3 was found to support effective disinfection performance. The findings demonstrated that high-frequency plasma treatment established a strong oxidative environment leading to microbial membrane disruption and cellular damage. Overall, the study confirmed the potential of high-frequency electrical discharge plasma technology as a promising approach for drinking water disinfection and provided a basis for further optimization and scale-up investigations. Full article
(This article belongs to the Section Water and One Health)
►▼ Show Figures

Figure 1

23 pages, 4040 KB  
Article
Pollutant Reductions in Step-Pool Streamwater Conveyances as Stream Restorations in Urban Catchments
by Michael R. Williams, Margaret A. Palmer and Solange Filoso
Water 2026, 18(6), 748; https://doi.org/10.3390/w18060748 - 22 Mar 2026
Viewed by 410
Abstract
Many degraded streams in the Chesapeake Bay watershed have been structurally modified over the last two decades in an effort to reduce nutrient and sediment loads from urban catchments and contribute to the pollutant reduction goals of the Chesapeake Bay Total Maximum Daily [...] Read more.
Many degraded streams in the Chesapeake Bay watershed have been structurally modified over the last two decades in an effort to reduce nutrient and sediment loads from urban catchments and contribute to the pollutant reduction goals of the Chesapeake Bay Total Maximum Daily Load (TMDL). The step-pool streamwater conveyance (SPSC) is a stream restoration design that has been extensively implemented in Maryland and the District of Columbia. In the summer of 2019, an SPSC was constructed in a degraded 800 m stream reach on the University of Maryland campus (i.e., Campus Creek). Precipitation, baseflow and stormflow runoff, and nutrient (nitrogen and phosphorus) and total suspended solid (TSS) concentrations were measured throughout pre- and post-restoration periods (~2 and 5 years, respectively) to determine the extent to which the SPSC structure reduced pollutant loads. A comparison of pre- (2018) versus post-restoration (2020) years with similar total annual rainfall volumes indicates that total annual runoff was 13% lower in the post-restoration period. Area yields of total nitrogen (TN), total phosphorus (TP) and TSS were 33, 39 and 59% lower, respectively, in the same pre- versus post-restoration comparison. Full article
(This article belongs to the Section Water Quality and Contamination)
►▼ Show Figures

Graphical abstract

37 pages, 3969 KB  
Article
An Integrated Resilience Assessment Framework for Riverine Bridges Based on Hydraulic Modeling and Multicriteria Analysis
by Diego Fabian Medina Yauri, Alejandra Muñoz-Manrique, Alan Huarca Pulcha and Alain Jorge Espinoza Vigil
Water 2026, 18(6), 746; https://doi.org/10.3390/w18060746 - 22 Mar 2026
Viewed by 646
Abstract
Riverine bridges are critical infrastructure that are increasingly exposed to severe hydrological hazards. This study proposes and validates a synergistic methodology for the assessment of riverine bridge resilience, integrating the conceptual 4R framework (robustness, rapidity, resourcefulness, and redundancy) with field inspections, hydrological and [...] Read more.
Riverine bridges are critical infrastructure that are increasingly exposed to severe hydrological hazards. This study proposes and validates a synergistic methodology for the assessment of riverine bridge resilience, integrating the conceptual 4R framework (robustness, rapidity, resourcefulness, and redundancy) with field inspections, hydrological and hydraulic modeling, including scour evaluation, within a multicriteria analysis scheme. The methodology comprises: (i) a systematic review of literature and regulations to construct a 30-parameter matrix across five dimensions (technical, economic, social, organizational, and environmental); (ii) data acquisition through field inspections, detailed topography, and technical studies; and (iii) one-dimensional hydraulic modeling in HEC-RAS under extreme scenarios (return periods of 100 to 750 years and a critical 500 m3/s scenario representing a potential overflow of the Aguada Blanca reservoir). The Bridge Resilience Index (BRI) is computed through a weighted additive model and a sensitivity analysis. Application to the San Martín Bridge (Arequipa, Peru), a structure with more than 60 years of service and recurrent preventive closures during flood events, revealed critical conditions: minimum freeboard of 0.26 m, absence of hydraulic protections, and limited institutional capacity. The resulting BRI value (1.898) indicates a low resilience level. The proposed framework provides a useful tool for risk-informed decision-making, the prioritization of interventions, and the strengthening of resilience in critical infrastructure. Full article
(This article belongs to the Special Issue Resilience and Risk Management in Urban Water Systems)
►▼ Show Figures

Figure 1

18 pages, 826 KB  
Article
Contamination of Two Drinking Water Catchments More than 24 Years After PFAS Foam Used to Suppress Highway Fuel Tanker Fires
by Ian A. Wright, Carmel Matheson, Amy-Marie Gilpin and Katherine G. Warwick
Water 2026, 18(6), 745; https://doi.org/10.3390/w18060745 - 22 Mar 2026
Viewed by 570
Abstract
In this study, the contamination of two drinking water catchments in Australia by per- and polyfluoroalkyl substances (PFAS) was investigated. PFASs in water and sediment were found at hazardous concentrations in waterways affected by transport accidents 24 and 33 years earlier. The exact [...] Read more.
In this study, the contamination of two drinking water catchments in Australia by per- and polyfluoroalkyl substances (PFAS) was investigated. PFASs in water and sediment were found at hazardous concentrations in waterways affected by transport accidents 24 and 33 years earlier. The exact cause(s) of the PFAS pollution remains unclear due to large data gaps. Both locations experienced burning fuel tankers suppressed using PFAS foam. PFAS contamination of a Blue Mountains water supply triggered the closure of two drinking water reservoirs 3–5 km downstream of the accident site. PFAS contamination of Central Coast’s Ourimbah Creek was concentrated in two floodplain wetlands adjacent to the accident site. The Ourimbah PFAS-affected wetlands are within 500 m of a drinking water groundwater bore field and 1.2 km from a raw water offtake used as part of Central Coast’s drinking water supply. The Blue Mountains contamination has impaired the Blue Mountains World Heritage Area, with perfluorooctane sulfonate (PFOS) exceeding aquatic ecosystem protection guidelines by 100 times. The mean PFOSs in stream water near the area of the Blue Mountains road accident were 2.16 µg L−1 and 213.3 µg kg−1 in stream sediment. This research demonstrates how spillages of small quantities of PFASs can cause major harm due to their extreme persistence, and their levels have exceedance of environmental and health guidelines for decades, with major adverse implications for drinking water supplies and conservation areas. Full article
(This article belongs to the Special Issue Review Papers of Urban Water Management 2026)
►▼ Show Figures

Figure 1

26 pages, 5081 KB  
Article
Upscaling WEPP Model to Project Spatial Variability of Soil Erosion in Agricultural-Dominant Watershed, India
by Vijayalakshmi Suliammal Ponnambalam, Nagesh Kumar Dasika, Haw Yen, Aubrey K. Winczewski, Dennis C. Flanagan, Chris S. Renschler and Bernard A. Engel
Water 2026, 18(6), 744; https://doi.org/10.3390/w18060744 - 22 Mar 2026
Viewed by 398
Abstract
The synergistic impacts of land use/land cover (LULC) transformations and weather pattern variabilities (WPV) represent a primary driver of hydro-geological instability, threatening agricultural productivity, soil conservation, and water quality. Disentangling the discrete contributions of these stressors to runoff and sediment yield (SY) remains [...] Read more.
The synergistic impacts of land use/land cover (LULC) transformations and weather pattern variabilities (WPV) represent a primary driver of hydro-geological instability, threatening agricultural productivity, soil conservation, and water quality. Disentangling the discrete contributions of these stressors to runoff and sediment yield (SY) remains a significant challenge, particularly in complex, confluence-proximal watersheds lacking major hydraulic regulations. This study investigates the Tirumakudalu Narasipura watershed in Karnataka, India, an agriculturally intensive system undergoing rapid peri-urbanization. Leveraging the process-based geospatial interface of the Water Erosion Prediction Project (GeoWEPP), we analyzed hydrological responses over a 24-year period (2000–2023) and projected future trajectories through 2030. To overcome the traditional constraints of GeoWEPP, which was developed for small-scale watersheds (<260 ha), we present a novel upscaling framework utilizing a multi-site multivariate temporal calibration of hydrological response variables to exploit its process-based precision in capturing distributed soil erosion and landscape heterogeneity. This approach is further reinforced by an ancillary data validation to minimize error propagation while model-upscaling. Our findings reveal projected increases in runoff and SY of 14.69% and 49.23%, respectively, between 2000 and 2030. Notably, the sub-decadal acceleration from 2023 to 2030 (17.32% for runoff and 18.51% for SY) underscores a shifting dominance where LULC-driven surface modifications now outweigh climatic variance in forcing hydrologic change. Furthermore, the study quantifies how anthropogenic interventions such as strategic crop selection, tillage intensity, and irrigation regimes act as critical determinants of topsoil preservation. These results provide a scalable, economically feasible framework for precision land stewardship and sustainable watershed management in rapidly developing tropical landscapes. Full article
(This article belongs to the Section Hydrology)
►▼ Show Figures

Figure 1

20 pages, 6149 KB  
Article
Application of Incomplete Topography Information and Public Data for Preliminary Flood Risk Assessment in Thailand: Case Study of Khlong Wat
by Supanon Kaiwong, Tomasz Dysarz and Joanna Wicher-Dysarz
Water 2026, 18(6), 743; https://doi.org/10.3390/w18060743 - 22 Mar 2026
Viewed by 657
Abstract
Flood hazard mapping remains challenging in regions with limited hydrological and topographic data, despite increasing flood risk driven by climate change and land-use dynamics. This study aims to demonstrate that preliminary flood inundation maps can be developed under data-scarce conditions by integrating limited [...] Read more.
Flood hazard mapping remains challenging in regions with limited hydrological and topographic data, despite increasing flood risk driven by climate change and land-use dynamics. This study aims to demonstrate that preliminary flood inundation maps can be developed under data-scarce conditions by integrating limited field observations with publicly available datasets and simplified hydrodynamic modeling. The Khlong Wat watershed in southern Thailand, where flood hazard maps had not previously existed despite recurrent flood events, was used as a case study. Flood simulations were conducted using the HEC-RAS model with a simplified terrain representation to approximate river bathymetry, acknowledging uncertainties in channel geometry. Hydrodynamic results show a systematic increase in flood extent and depth with increasing flood recurrence intervals, with inundated areas expanding from 1.43 km2 for a 10-year flood to 4.02 km2 and 5.97 km2 for 100- and 500-year events, respectively. Agricultural land is consistently the most affected category, accounting for more than two-thirds of the flooded area across all scenarios, with rubber plantations being the dominant land use. Urban exposure increases with flood magnitude, although most buildings remain affected by shallow inundation below 0.5 m. The results confirm that meaningful flood hazard assessments can be achieved in data-limited regions and provide a transferable framework to support flood risk management and spatial planning in similar environments. Full article
(This article belongs to the Special Issue Hydrological Hazards: Monitoring, Forecasting and Risk Assessment)
►▼ Show Figures

Graphical abstract

16 pages, 1756 KB  
Article
Evaluating Performance Limitations in Aquaponic vs. Hydroponic: Dynamics of Nutrient Release by Fish and Accumulation Rate in Plants
by Syed Ejaz Hussain Mehdi, Aparna Sharma, Suleman Shahzad, Woochang Kang, Sandesh Pandey, Byung-Jun Park, Hyuck-Soo Kim and Sang-Eun Oh
Water 2026, 18(6), 742; https://doi.org/10.3390/w18060742 - 22 Mar 2026
Viewed by 501
Abstract
Aquaponics (AP) is the combination of aquaculture and hydroponic systems, developed based on waste to wealth theory. This study compared the plant growth and overall productivity of an aquaponic system (AP) with a controlled hydroponic system (HP) to assess the AP system’s performance [...] Read more.
Aquaponics (AP) is the combination of aquaculture and hydroponic systems, developed based on waste to wealth theory. This study compared the plant growth and overall productivity of an aquaponic system (AP) with a controlled hydroponic system (HP) to assess the AP system’s performance and identification of the performance-limiting factors. This comparative study spanned over a 35-day period, supported by batch tests for the nutrient accumulation rate in plants and the NH4+-N excretion rate by fish as a baseline for the system design. HP performed better in terms of plant growth, showing a mean plant fresh weight (g) of 165.6 ± 3.01 while AP showed 147.0 ± 4.6. Nutrient accumulation was better in HP for K and P; however, Ca2+, Mg2+, and Fe accumulation was higher in AP plants. The AP system supported a better fish growth of 31.95 ± 3.21% (FCR 1.29 ± 0.1, SGR 0.79 ± 0.06, and PER 2.24 ± 0.18) and a moderate plant biomass production. Further system design modifications and integrations are required to optimize the nutrient availability and sustainability of the AP systems. Full article
(This article belongs to the Special Issue Advanced Aquaculture Water Quality Management Research)
►▼ Show Figures

Figure 1

19 pages, 828 KB  
Article
Tribal Water Rights Settlement Acts Involving Arizona and Their Impacts on Water Security
by Aminta Menjivar Maldonado, Sharon B. Megdal and Heather Whiteman Runs Him
Water 2026, 18(6), 741; https://doi.org/10.3390/w18060741 - 22 Mar 2026
Viewed by 1171
Abstract
In the western part of the United States, surface water rights follow the prior appropriation doctrine, while tribal water rights are governed by the reserved water rights doctrine. States and Tribal Nations share borders, but water knows no boundaries, and water-related conflicts emerged [...] Read more.
In the western part of the United States, surface water rights follow the prior appropriation doctrine, while tribal water rights are governed by the reserved water rights doctrine. States and Tribal Nations share borders, but water knows no boundaries, and water-related conflicts emerged by the late 19th Century. The United States Supreme Court recognized the reserved water rights doctrine through Winters v. United States in 1908. Over a century later, many tribal water rights claims remain unresolved. Since 1978, congressionally approved tribal water rights settlement acts have emerged as a way to resolve pending tribal water rights claims in the United States. As of March 2026, Tribal Nations, Arizona, the United States, and other interested parties have negotiated 11 congressionally approved tribal water rights settlement acts. This article qualitatively analyzes these 11 congressionally approved tribal water rights settlement acts. The historical and legal analysis highlights the importance of water sharing through water rights settlement acts to ensure water security for Arizona, Tribal Nations, and other interested parties. Full article
(This article belongs to the Special Issue Working Across Borders to Address Water Scarcity)
►▼ Show Figures

Figure 1

29 pages, 11791 KB  
Article
Cluster-Aware Prediction of Rainfall-Induced Landslide Run-Out Distance Using AE-Optimized LightGBM with TreeSHAP Interpretation
by Dan Li, Kuanghuai Wu, Yiming Li, Jian Huang and Xian Liu
Water 2026, 18(6), 740; https://doi.org/10.3390/w18060740 - 22 Mar 2026
Viewed by 309
Abstract
Accurate prediction of landslide run-out distance is fundamental to hazard mapping, emergency planning, and risk-informed engineering design. However, many data-driven studies implicitly treat landslides as a homogeneous population and provide limited, physically interpretable insights into how geomorphic factors govern run-out behavior. To address [...] Read more.
Accurate prediction of landslide run-out distance is fundamental to hazard mapping, emergency planning, and risk-informed engineering design. However, many data-driven studies implicitly treat landslides as a homogeneous population and provide limited, physically interpretable insights into how geomorphic factors govern run-out behavior. To address these limitations, we propose a cluster-aware and explainable modeling framework to predict run-out distance L using four source-region and slope descriptors: crown–toe relief H, source area A, source volume V, and mean source-slope inclination θ. The dataset consists of 10,159 rainfall-induced landslides compiled from official inventories and peer-reviewed literature. After standardizing predictors, the optimal number of clusters is determined using information criteria (AIC/BIC), followed by k-means clustering to identify distinct landslide regimes. We first benchmark Random Forest, eXtreme Gradient Boosting, CatBoost, and LightGBM on identical data splits without hyperparameter tuning, using R2, RMSE, and MAE as performance metrics. LightGBM consistently outperforms the alternatives and is therefore selected as the base learner. Within each cluster, LightGBM is further optimized using the Alpha Evolution (AE) algorithm, with Particle Swarm Optimization and Bayesian Optimization serving as benchmarks. The resulting AE-LightGBM model achieves the highest predictive accuracy across clusters. Model interpretability is achieved using TreeSHAP, which decomposes predictions into cluster-specific baselines and additive contributions from H, A, V, and θ. By integrating regime-sensitive learning with robust explainability, the proposed framework improves run-out distance prediction while providing transparent, physically meaningful insights to support scenario analysis and engineering decision-making. Full article
(This article belongs to the Special Issue Approaches to Water-induced Landslide Hazard Risk Forecasting and Assessment)
►▼ Show Figures

Figure 1

35 pages, 4208 KB  
Article
Surrogate-Assisted Techno-Economic Optimization to Reduce Saltwater Disposal via Produced-Water Valorization: A Permian Basin Case Study
by Ayann Tiam, Elie Bechara, Marshall Watson and Sarath Poda
Water 2026, 18(6), 739; https://doi.org/10.3390/w18060739 - 21 Mar 2026
Viewed by 535
Abstract
Produced-water (PW) management in the Permian Basin faces tightening injection constraints, induced seismicity concerns, and volatile saltwater disposal (SWD) costs. At the same time, chemistry-rich PW contains dissolved constituents (e.g., Li, B, and Sr) that may be valorized if SWD recovery performance and [...] Read more.
Produced-water (PW) management in the Permian Basin faces tightening injection constraints, induced seismicity concerns, and volatile saltwater disposal (SWD) costs. At the same time, chemistry-rich PW contains dissolved constituents (e.g., Li, B, and Sr) that may be valorized if SWD recovery performance and market conditions support favorable techno-economics. Here, we develop an integrated decision-support framework that couples (i) chemistry-informed surrogate models for unit process performance (recovery, effluent quality, and energy/chemical intensity) with (ii) a network-based allocation model that routes PW from sources through pretreatment, optional treatment and mineral-recovery modules (e.g., desalination and direct lithium extraction), and end-use nodes (beneficial reuse, hydraulic fracturing reuse, mineral recovery/valorization, or Class II disposal). This is a screening-level demonstration using publicly available chemistry percentiles and representative pilot-reported performance windows; it is not a site-specific facility design or a bankable TEA for a particular operator. The optimization is posed as a tri-objective problem—to maximize expected net present value, minimize SWD, and minimize an injection-risk indicator R—subject to mass balance, capacity, quality, and regulatory constraints. Uncertainty in commodity prices, recovery fractions, and operating costs is propagated via Monte Carlo scenario sampling, yielding PARETO-efficient portfolios that quantify trade-offs between profitability and risk mitigation. Using the PW chemistry percentiles reported by the Texas Produced Water Consortium for the Delaware and Midland Basins, we derive screening-level break-even lithium concentrations and illustrate how lithium-carbonate-equivalent price and recovery govern the extent to which mineral revenue can offset SWD expenditures. Comparative brine benchmarks (Smackover Formation and Salton Sea geothermal systems) contextualize the Permian’s generally lower-Li PW and highlight transferability of the workflow across brine types. The proposed framework provides a transparent, extensible basis for design matrix planning under evolving injection limits, enabling risk-aware PW management strategies that reduce disposal dependence while improving water resilience. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
►▼ Show Figures

Figure 1

18 pages, 3663 KB  
Article
Cooling–Heating Phase Behavior of Hypersaline Culture Media Studied by DSC and Cryomicroscopy
by Olena Bobrova, Nadiia Chernobai, Nadiia Shevchenko, Viktor Husak and Alexander Shyichuk
Water 2026, 18(6), 738; https://doi.org/10.3390/w18060738 - 21 Mar 2026
Viewed by 433
Abstract
Hypersaline culture media used for cultivation of Dunaliella salina represent complex multicomponent aqueous systems whose cooling–heating phase behavior remains insufficiently characterized. In this study, the thermal transitions of two biologically relevant hypersaline media (Artari and Ramaraj) were investigated using differential scanning calorimetry (DSC) [...] Read more.
Hypersaline culture media used for cultivation of Dunaliella salina represent complex multicomponent aqueous systems whose cooling–heating phase behavior remains insufficiently characterized. In this study, the thermal transitions of two biologically relevant hypersaline media (Artari and Ramaraj) were investigated using differential scanning calorimetry (DSC) and cryomicroscopy. The media were examined at NaCl concentrations of 1.5, 2.0, and 4.0 M, corresponding to moderate to highly concentrated brine conditions comparable to natural salt lakes and evaporative basins. DSC analysis revealed pronounced salinity-dependent suppression of ice crystallization and modification of melting transitions relative to classical NaCl–water systems. Increased NaCl concentration reduced recrystallization during heating and shifted peak temperatures, indicating kinetic and compositional effects in the unfrozen fraction. Rapid cooling promoted formation of partially amorphous phases, consistent with limited vitrification in highly concentrated media. Cryomicroscopy directly confirmed changes in ice morphology, nucleation density, and crystal growth dynamics under varying salinity and thermal histories. The combined calorimetric and microscopic approach demonstrates that complete hypersaline cultivation media exhibit phase behavior that cannot be fully extrapolated from simplified binary systems. These findings provide new insight into the physicochemical stability of multicomponent brines during cooling and highlight the critical role of salinity and thermal history in controlling crystallization pathways in hypersaline aqueous environments. Full article
(This article belongs to the Section Water, Agriculture and Aquaculture)
►▼ Show Figures

Graphical abstract

23 pages, 9539 KB  
Article
A Probability-Based Risk Assessment Model for the Sustainable Management of Urban Wastewater Collection Systems
by Cansu Bozkurt
Water 2026, 18(6), 737; https://doi.org/10.3390/w18060737 - 21 Mar 2026
Viewed by 373
Abstract
Sewerage systems are among the most fundamental and indispensable components of urban infrastructure. However, inadequate management can result in malfunctions and subsequent rehabilitation processes, leading to various negative consequences. Identifying areas at high risk of failure and conducting system-based inspections can significantly improve [...] Read more.
Sewerage systems are among the most fundamental and indispensable components of urban infrastructure. However, inadequate management can result in malfunctions and subsequent rehabilitation processes, leading to various negative consequences. Identifying areas at high risk of failure and conducting system-based inspections can significantly improve the performance of sewer networks. This study identified and categorized 33 criteria that could cause sewer system failures: structural, operational, hydraulic and environmental defects. A Bayesian network (BN) model was developed to determine dependencies between the criteria, quantify uncertainty, investigate new information about the structural condition of assets and calculate the effects and sensitivities of the criteria on the probability of failure. A probability-based risk assessment model was then created using a fuzzy inference system (FIS) to predict risk levels in sewerage systems under different combinations of physical and operational conditions and hydraulic and environmental effects. A case study was performed on a sewer network in Malatya, Turkey, determining its failure probability to be 76.6%, placing it in the high-risk category. When the probability of pipe failure was set to 100% in the Bayesian network model to evaluate the relative influence of different criteria, the most influential factors were identified as flow velocity (74.8%), clogging (71.4%), and failure rate (71.1%). Thanks to the flexible structure of BNs, the proposed model is expected to be useful for performing risk analyses in systems involving uncertainty or missing data. It can also be used to prioritize rehabilitation, inspection and maintenance programs, improve infrastructure service quality and ensure system reliability in urban sewerage systems. Full article
(This article belongs to the Special Issue Research on Water Supply Systems and on the Treatment and Recovery of Wastewater and Stormwater)
►▼ Show Figures

Figure 1

26 pages, 5758 KB  
Article
Analyzing Emergency Service Performance and Fastest Rescue Routes to Vulnerable Population Places Under Compound Pluvial Flooding and Traffic Congestion
by Fan Yi, Hao Jia, Chengyu Liang, Qifei Zhang, Yanmei Wang, Yafei Wang and Hui Zhang
Water 2026, 18(6), 736; https://doi.org/10.3390/w18060736 - 20 Mar 2026
Viewed by 618
Abstract
The combined impacts of urban pluvial flooding and traffic congestion can severely delay emergency response. However, existing studies often focus on isolated scenarios, failing to systematically quantify the reduction in overall service capability and specific route disruptions to critical functional nodes under compound [...] Read more.
The combined impacts of urban pluvial flooding and traffic congestion can severely delay emergency response. However, existing studies often focus on isolated scenarios, failing to systematically quantify the reduction in overall service capability and specific route disruptions to critical functional nodes under compound hazards. To address this problem, this study proposes a three-tier analytical framework to systematically evaluate the resilience of emergency services under compound hazards. The framework first utilizes spatial network analysis to simulate the overall spatial evolution of service capabilities for Emergency Medical Service (EMS) and Fire and Rescue Service (FRS) across various return periods and traffic conditions. It then delves into the emergency response coverage for vulnerable population places. Finally, the fastest-route analysis is employed to identify variations in rescue routing. The study reveals several critical insights. (1) As rainfall intensity and traffic congestion intensify, the coverage areas of EMS and FRS exhibit significant contraction and boundary erosion. Notably, the service areas of FRS show a distinct fragmentation pattern. (2) The protection levels for vulnerable population places (e.g., kindergartens, primary and secondary schools, and nursing homes) show a pronounced stepwise decline. Under extreme rainfall and the heaviest congestion, the 5 min coverage for these sites drops from 89.9% to 23.6% for EMS, and from 72.4% to only 15.1% for FRS, revealing a severe risk exposure for vulnerable groups. (3) Road inundation leads to a substantial extension of rescue routes and even results in the complete isolation of 141 primary and secondary schools. Overall, the framework provides actionable decision support to enhance urban emergency response under compound hazards. Full article
(This article belongs to the Special Issue Water-Related Disaster Assessments and Prevention)
►▼ Show Figures

Figure 1

19 pages, 12766 KB  
Article
Evaluating the Resilience Gap: What Can Modern Beijing Learn from the Historical Water System of Yuan Dadu (1267–1368 CE)?
by Zi Hui and Jiaping Liu
Water 2026, 18(6), 735; https://doi.org/10.3390/w18060735 - 20 Mar 2026
Viewed by 411
Abstract
Urban flood resilience is an important indicator for measuring a city’s capacity to respond to and recover from flood disasters. However, existing assessments often lack a long-term hydrological baseline. This study establishes the historical water system of Yuan Dadu (1267–1368 CE) as a [...] Read more.
Urban flood resilience is an important indicator for measuring a city’s capacity to respond to and recover from flood disasters. However, existing assessments often lack a long-term hydrological baseline. This study establishes the historical water system of Yuan Dadu (1267–1368 CE) as a control scenario to benchmark the flood resilience of modern Beijing. By integrating a historical geographic reconstruction with a hydrological–hydrodynamic simulation and the fuzzy analytic hierarchy process (FAHP), the research quantifies structural differences in resilience profiles between the nature-adapted historical system and the modern engineering-dominated system. The results indicate that Yuan Dadu’s urban flood resilience index (UFRI) is 3.44 and modern Beijing’s is 3.28. Despite modern Beijing’s significant advantage in drainage facility density (0.61 km/km2) and emergency management, the system exhibits a functional substitution failure, where gray infrastructure has failed to fully compensate for a 26% reduction in the unit area storage capacity (from 6.4 to 4.7 × 104 m3/km2) and a 48.4% decline in the water system structural complexity. The findings indicate that, in rapidly urbanized cities on alluvial plains with high impervious coverage, expanding drainage networks alone may be insufficient to offset losses in a natural hydraulic buffering capacity. Accordingly, planning strategies are proposed that integrate distributed micro-storage and restore topological connectivity to recreate system-level hydraulic buffering functions. Full article
(This article belongs to the Special Issue Urban Drainage Systems and Stormwater Management, 2nd Edition)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-117
Previous Issue
Next Issue
Back to TopTop