Water

22 pages, 7694 KiB

Open AccessArticle

Mountain Flood Risk: A Bibliometric Exploration Across Three Decades

by Qian Li, Yuanbin Tang, Shuai Wang, Xiuguang Wu and Yong Luan

Water 2025, 17(10), 1513; https://doi.org/10.3390/w17101513 (registering DOI) - 16 May 2025

Climate change, intensified human activities, and ecological shifts have markedly increased mountain flood risks, threatening communities in vulnerable highland regions. This study used CiteSpace (6.2R6) and VOSviewer (1.6.20) to analyze 1841 Web of Science Core Collection articles (1995–2024), mapping publication and citation trends, [...] Read more.

Climate change, intensified human activities, and ecological shifts have markedly increased mountain flood risks, threatening communities in vulnerable highland regions. This study used CiteSpace (6.2R6) and VOSviewer (1.6.20) to analyze 1841 Web of Science Core Collection articles (1995–2024), mapping publication and citation trends, leading countries and institutions, co-citation networks, and keyword dynamics. We found an exponential increase in output (CAGR 15.8%), peaking at 211 articles in 2024. China (23.7%, 436 articles), the United States (17.8%, 328), Italy (8.6%, 159), India (5.5%, 101), and Japan (4.2%, 77) are leading research countries in the field, which is underpinned by extensive international collaboration. The research spans diverse domains with robust interdisciplinary integration. Keyword timeline and burst analyses reveal emerging topics—machine learning-enhanced risk assessment, climate-driven flood dynamics in the Himalayas and Alps, hydrological process modeling, and socio-economic impact evaluation—pointing toward advanced, region-tailored solutions. Full article

(This article belongs to the Section Hydrology)

25 pages, 3879 KiB

Open AccessArticle

Adaptive PID Control of Hydropower Units Based on Particle Swarm Optimization and Fuzzy Inference

by Dong Liu, Shichao Zhao and Jingjing Zhang

Water 2025, 17(10), 1512; https://doi.org/10.3390/w17101512 (registering DOI) - 16 May 2025

Abstract

Currently, fixed-parameter proportional–integral–derivative (PID) control is widely adopted by the governor of hydropower units (HPUs), which causes regulation performance to deteriorate during variable operating conditions. To solve this problem, a novel particle swarm optimization-based fuzzy PID (PSO-FPID) is proposed for the frequency regulation [...] Read more.

Currently, fixed-parameter proportional–integral–derivative (PID) control is widely adopted by the governor of hydropower units (HPUs), which causes regulation performance to deteriorate during variable operating conditions. To solve this problem, a novel particle swarm optimization-based fuzzy PID (PSO-FPID) is proposed for the frequency regulation of HPUs. The segment linearization model of HPU is first established to reflect the changes in the operating conditions. On this basis, FPID is designed based on expert experience. The PID control parameters are optimized using PSO under different operating conditions to determine the optimal initial values of the FPID controller. To verify the effectiveness of the proposed PSO-FPID, its performance is compared and analyzed with the actual PID, FPID, and particle swarm optimization-based PID (PSO-PID) in the MATLAB/Simulink platform. The results show that the average adjust time of PSO-FPID is 16.60 s less than that of PID, 18.05 s less than that of FPID, and 0.23 s less than that of PSO-PID. PSO-FPID can maintain better control performance than the other methods under most operating conditions. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

29 pages, 16679 KiB

Open AccessArticle

Advancing Ion Constituent Simulations in California’s Sacramento–San Joaquin Delta Using Machine Learning Tools

by Peyman Namadi, Minxue He and Prabhjot Sandhu

Water 2025, 17(10), 1511; https://doi.org/10.3390/w17101511 (registering DOI) - 16 May 2025

Abstract

This study extends previous machine learning work on ion constituent simulation in California’s Sacramento–San Joaquin Delta (Delta) to include three critical water intake locations. The developed Artificial Neural Network models demonstrate exceptional accuracy (R² > 0.96) in predicting chloride, bromide, and sulfate [...] Read more.

This study extends previous machine learning work on ion constituent simulation in California’s Sacramento–San Joaquin Delta (Delta) to include three critical water intake locations. The developed Artificial Neural Network models demonstrate exceptional accuracy (R² > 0.96) in predicting chloride, bromide, and sulfate concentrations at these strategically important facilities. Water intake location models show substantial improvements in prediction accuracy, with MAE reductions of 60.7–74.0% for chloride, 63.3–72.5% for bromide, and 70.4–87.9% for sulfate, compared to existing methods for the Interior Delta. Performance evaluation through comprehensive cross-validation confirms robust model stability across varied conditions, with remarkably consistent metrics (standard deviation in R² ≤ 0.006). Four complementary interactive dashboards were developed, enabling users, regardless of programming expertise, to simulate ion constituents throughout the Delta system. A Model Interpretability Dashboard specifically addresses the complexity of machine learning models by visualizing parameter sensitivity and prediction behavior, thereby enhancing transparency and building stakeholder trust in the modeling approach. For the first time, spatial coverage limitations are addressed through hybrid modeling that combines DSM2 hydrodynamic simulation with machine learning to enable continuous prediction of ion distributions across several points in the Interior Delta. These advancements provide water managers with accessible, accurate tools for informed decision-making regarding agricultural operations, drinking water treatment, and ecosystem management in this vital water resource. Full article

(This article belongs to the Special Issue Machine Learning Applications in the Water Domain)

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20 pages, 14265 KiB

Open AccessArticle

A Tombolo Alternating Between a Double Tombolo and a Salient on the West Coast of Honghai Bay, Guangdong, China, Driven by Dynamic Fluvial and Coastal Interactions

by Mingkun Qiu and Wei Wang

Water 2025, 17(10), 1510; https://doi.org/10.3390/w17101510 - 16 May 2025

Abstract

A small tombolo on the west coast of Guangdong’s Honghai Bay was investigated using over a decade of satellite imagery. Occasionally, this stream forms a lagoon behind the island, giving the appearance of a double tombolo. However, analysis of satellite imagery reveals that [...] Read more.

A small tombolo on the west coast of Guangdong’s Honghai Bay was investigated using over a decade of satellite imagery. Occasionally, this stream forms a lagoon behind the island, giving the appearance of a double tombolo. However, analysis of satellite imagery reveals that the double tombolo was not consistently formed and that the tombolo tip was not always attached to the leeward side of the island. This suggests that the tombolo was in a transitional state between the formation of a tombolo and a salient. The beaches on both sides of the tombolo are headland-bay beaches. Therefore, MEPBAY and XBeach, coupled with grain size analysis, were utilized to investigate the dynamic geomorphological processes of the tombolo. This study shows that the headlands at both ends of the beaches, along with waves approaching perpendicular to the shore, inhibit longshore drift on either side of the tombolo. The sediment sustaining the tombolo originates from the stream sands and offshore sands transported onshore by waves. When wave-driven sediment transport exceeds stream sediment supply, a tombolo forms. Conversely, only a salient develops. This specific case study reveals previously undocumented phenomena, thereby offering valuable insights into the mechanisms of double tombolo formation. Full article

(This article belongs to the Special Issue Study on Environmental Hydrology and Hydrodynamic Characteristics of Basins, Estuaries and Offshore)

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27 pages, 2432 KiB

Open AccessArticle

Sustainable Bioremediation of Lipid-Rich Wastewater Using a Lipase from Penicillium rubens LBM 081

by Laura Ester Ortellado, Alan Rolando Ayala Schimpf, Silvana Florencia Benítez, Laura Lidia Villalba, Pedro Darío Zapata and María Isabel Fonseca

Water 2025, 17(10), 1509; https://doi.org/10.3390/w17101509 - 16 May 2025

Abstract

The improper discharge of wastewater has increased the presence of pollutants, among which lipids are particularly problematic. These compounds form oily layers that hinder oxygen transfer and sunlight penetration, negatively impacting aquatic ecosystems. Conventional methods for treating such effluents are often costly and [...] Read more.

The improper discharge of wastewater has increased the presence of pollutants, among which lipids are particularly problematic. These compounds form oily layers that hinder oxygen transfer and sunlight penetration, negatively impacting aquatic ecosystems. Conventional methods for treating such effluents are often costly and environmentally unfriendly. In this context, bioremediation using lipases, such as those produced by Penicillium rubens LBM 081, represents an effective and sustainable alternative. This study evaluated the biotechnological potential of the lipase from P. rubens LBM 081 for the hydrolysis of lipid-rich wastewater. Lipase activity was influenced by the carbon and nitrogen sources in the culture medium, reaching maximum activity (2780 U mL⁻¹) under optimal conditions of 2% meat peptone, 4% olive oil, a spore concentration of 1 × 10⁶, incubation at 30 °C, and agitation at 140 rpm. The optimized enzymatic supernatant significantly reduced COD, oils, and total fats in the effluents. Furthermore, GC-MS analysis revealed a significant increase in free fatty acids, confirming triglyceride hydrolysis. These results highlight the potential of P. rubens LBM 081 lipase as an effective and environmentally sustainable biotechnological alternative for the treatment of lipid-rich wastewater. Full article

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

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16 pages, 5555 KiB

Open AccessArticle

Water Inrush Mechanism During Mining Adjacent to Large Water-Conducting Faults

by Xiaofei Gong, Dan Ma, Luyuan Wu, Qiang Li, Zhenhua Li, Feng Du, Rui Qiao and Jiufang Han

Water 2025, 17(10), 1508; https://doi.org/10.3390/w17101508 - 16 May 2025

Abstract

In mining operations, the rock mass located between the water-conducting fault fracture zone and the waterproof protective coal column is highly susceptible to damage, which may result in sudden water inrush disasters. This paper first employs indoor experiments and on-site rock sample analysis [...] Read more.

In mining operations, the rock mass located between the water-conducting fault fracture zone and the waterproof protective coal column is highly susceptible to damage, which may result in sudden water inrush disasters. This paper first employs indoor experiments and on-site rock sample analysis to determine the macroscopic mechanical parameters of rocks and rock masses, as well as the microscopic mechanical parameters of block contacts. The fracture and seepage evolution mechanisms in the mining-induced rock mass adjacent to major faults were analyzed utilizing the discrete element-fluid coupling theory in Universal Distinct Element Code (UDEC). The results identified three primary pathways for water hazards caused by mining: the calculated stress field and seepage field indicated that the formation of the water-inrush channels was determined by the parameters of coal seam mining. Different waterproof protective coal columns were set up for the three geological conditions under study. Additionally, a “claw-shaped” detection and flow monitoring method has been proposed for small water-conducting faults. These findings are important and provide valuable guidance for understanding and managing water inrush hazards in mining operations near major faults. Full article

(This article belongs to the Special Issue Water-Induced Geo-Disaster Reduction in the Context of Climate Change: Hydrology, Management Strategies, and Ecological Geological Engineering)

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29 pages, 28377 KiB

Open AccessArticle

Assessment of Future Drought Characteristics Using Various Temporal Scales and Multiple Drought Indices over Mekong Basin Under Climate Changes

by Vo Quang Tuong, Bui Anh Kiet and Thu T. Pham

Water 2025, 17(10), 1507; https://doi.org/10.3390/w17101507 - 16 May 2025

Abstract

This study evaluates the performance of CMIP6 models in simulating drought characteristics in the Mekong region, including drought duration, intensity, and severity, using the SPI and SPEI indices. The results show that CMIP6 models are capable of accurately reproducing past drought conditions, with [...] Read more.

This study evaluates the performance of CMIP6 models in simulating drought characteristics in the Mekong region, including drought duration, intensity, and severity, using the SPI and SPEI indices. The results show that CMIP6 models are capable of accurately reproducing past drought conditions, with a high agreement between model data and actual data from ERA5. This study projects that future droughts will become more prolonged and severe which could lead to long-term agricultural and hydrological droughts tending to increase. In the SSP585 scenario, drought intensity will increase sharply in the southern and central regions by the end of the century. The SSP245 and SSP585 climate scenarios have distinct differences in drought trends, with SSP245 showing a strong drought trend, while SSP585 indicates a potential increase in precipitation. The SPEI indices show a clear improvement in wet conditions, with the highest drought variability in zone 2 and stable trends across scenarios. Ecosystems influence drought impacts and management needs. These results highlight the importance of accurately assessing drought characteristics to develop effective water resource and agricultural management measures, especially in the context of climate change. However, this study also points out some limitations, including the imperfect accuracy in future projections and the use of only SPI and SPEI indices without combining them with other indices which may reduce the comprehensiveness of drought impact assessment. This requires future studies to improve and expand to overcome the above limitations, thereby enhancing the reliability of drought forecasts and water resource management strategies. Full article

(This article belongs to the Topic Water Management in the Age of Climate Change)

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17 pages, 1403 KiB

Open AccessArticle

Research and Application Analysis of Intelligent Control Strategy for Water Injection Pump in Offshore Oil and Gas Field

by Weizheng An, Yingyi Ma, Haibo Xu, Erqinhu Ke, Xianjie Liao and Ruijie Zhao

Water 2025, 17(10), 1506; https://doi.org/10.3390/w17101506 - 16 May 2025

Abstract

This paper discusses the energy-saving control method of a pipeline network system based on reinforcement learning and a genetic algorithm and compares it with traditional control methods such as constant-pressure control and non-frequency conversion control. The purpose is to improve the operational efficiency [...] Read more.

This paper discusses the energy-saving control method of a pipeline network system based on reinforcement learning and a genetic algorithm and compares it with traditional control methods such as constant-pressure control and non-frequency conversion control. The purpose is to improve the operational efficiency of an offshore oil and gas field water injection system. This paper simulates and verifies the experimental platform of a water injection system pipe network in offshore oil and gas fields and evaluates the optimization effect of different control strategies under different flow rates. The experimental results reveal that under a varying flow rate, the water injection system harnessing the GA and RL exhibits a remarkable energy-saving advantage over traditional control methods. Specifically, the GA strategy achieves an average energy-saving rate of 22.51%, with a maximum energy-saving rate of 38.14% under low flow rate, while the RL strategy attains an average energy-saving rate of 18.39%. These methodologies not only furnish novel solutions for the real-time optimal scheduling of water injection systems in offshore oil and gas fields but also proffer practical guidance, thereby paving the way for technological advancement and sustainable development in the industry. Full article

(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 3rd Edition)

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21 pages, 2985 KiB

Open AccessArticle

Linkage Analysis Between Coastline Change and Both Sides of Coastal Ecological Spaces

by Xianchuang Fan, Chao Zhou, Tiejun Cui, Tong Wu, Qian Zhao and Mingming Jia

Water 2025, 17(10), 1505; https://doi.org/10.3390/w17101505 - 16 May 2025

Abstract

As the first marine economic zone, the coastal zone is a complex and active ecosystem, serving as an important resource breeding area. However, during the process of economic development, coastal zone resources have been severely exploited, leading to fragile ecology and frequent natural [...] Read more.

As the first marine economic zone, the coastal zone is a complex and active ecosystem, serving as an important resource breeding area. However, during the process of economic development, coastal zone resources have been severely exploited, leading to fragile ecology and frequent natural disasters. Therefore, it is imperative to analyze coastline changes and their correlation with coastal ecological space. Utilizing long-time series high-resolution remote sensing images, Google Earth images, and key sea area unmanned aerial vehicle (UAV) remote sensing monitoring data, this study selected the coastal zone of Ningbo City as the research area. Remote sensing interpretation mark databases for coastline and typical coastal ecological space were established. Coastline extraction was completed based on the visual discrimination method. With the help of the Modified Normalized Difference Water Index (MNDWI), Normalized Difference Vegetation Index (NDVI) and maximum likelihood classification, a hierarchical classification discrimination process combined with a visual discrimination method was constructed to extract long-time series coastal ecological space information. The changes and the linkage relationship between the coastlines and coastal ecological spaces were analyzed. The results show that the extraction accuracy of ground objects based on the hierarchical classification process is high, and the verification effect is improved with the help of UAV remote sensing monitoring. Through long-time sequence change monitoring, it was found that the change in coastline traffic and transportation is significant. Changes in ecological spaces, such as industrial zones, urban construction, agricultural flood wetlands and irrigation land, dominated the change in artificial shorelines, while the change in Spartina alterniflora dominated the change in biological coastlines. The change in ecological space far away from the coastline on both the land and sea sides has little influence on the coastline. The research shows that the correlation analysis between coastline and coastal ecological space provides a new perspective for coastal zone research. In the future, it can provide technical support for coastal zone protection, dynamic supervision, administration, and scientific research. Full article

(This article belongs to the Special Issue Advanced Remote Sensing for Coastal System Monitoring and Management)

26 pages, 7848 KiB

Open AccessArticle

The Impact of Inundation and Nitrogen on Common Saltmarsh Species Using Marsh Organ Experiments in Mississippi

by Kelly M. San Antonio, Wei Wu, Makenzie Holifield and Hailong Huang

Water 2025, 17(10), 1504; https://doi.org/10.3390/w17101504 - 16 May 2025

Abstract

Sea level rise is an escalating threat to saltmarsh ecosystems as increased inundation can lead to decreased biomass, lowered productivity, and plant death. Another potential stressor is elevated nitrogen often brought into coastal regions via freshwater diversions. Nitrogen has a controversial impact on [...] Read more.

Sea level rise is an escalating threat to saltmarsh ecosystems as increased inundation can lead to decreased biomass, lowered productivity, and plant death. Another potential stressor is elevated nitrogen often brought into coastal regions via freshwater diversions. Nitrogen has a controversial impact on belowground biomass, potentially affecting saltmarsh stability. In this study, we examined the effects of inundation and nitrogen on common saltmarsh plants (Spartina alterniflora and Spartina patens) placed within two marsh organs (a collection of PVC pipes at different levels, the varied elevation levels expose the plants to different inundation amounts) located in the Pascagoula River, Mississippi, USA, with six rows and eight replicates in each row. We randomly fertilized four replicates in each row with 25 g/m² of NH4⁺-N every two-three weeks during the growing season in 2021 and 2022. We concurrently collected vegetative traits such as plant height and leaf count to better understand strategies saltmarshes utilize to maximize survival or growth. We harvested half of the vegetation in Year 1 and the remaining in Year 2 to evaluate the impact of inundation and nitrogen on above- and belowground biomass at different temporal scales. We developed Bayesian models that show inundation had a largely positive impact on S. alterniflora and a mostly negative impact S. patens, suggesting that S. alterniflora will adapt better to increasing inundation than S. patens. Additionally, fertilized plants from both species had higher aboveground biomass than non-fertilized plants for both years, with nitrogen addition only showing impact on belowground biomass in the long term. Our results highlight the importance of long-term study to facilitate more-informed restoration and conservation efforts in coastal wetlands while accounting for climate change and sea level rise. Full article

(This article belongs to the Special Issue New Insights into Sea Level Dynamics and Coastal Erosion)

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17 pages, 5451 KiB

Open AccessArticle

Design of a Novel Pump Cavitation Valve and Study of Its Cavitation Characteristics

by Yang Luo, Zhenxing Wu, Zekai Li, Lang Cheng, Peihan Qi and Jiegang Mou

Water 2025, 17(10), 1503; https://doi.org/10.3390/w17101503 - 16 May 2025

Abstract

In centrifugal pump open cavitation tests, cavitation regulation valves are indispensable. During valve regulation, the irregular shape of the flow cross-section easily induces cavitation, significantly affecting the test results. This study investigates and designs a novel cavitation regulation valve. The valve core is [...] Read more.

In centrifugal pump open cavitation tests, cavitation regulation valves are indispensable. During valve regulation, the irregular shape of the flow cross-section easily induces cavitation, significantly affecting the test results. This study investigates and designs a novel cavitation regulation valve. The valve core is composed of several identical valve flaps. By restricting the movement direction and distance of the valve flaps, the shape of the flow cross-section remains circular under different valve openings, ensuring optimal fluid flow conditions. This study examines the influence of the number of valve flaps on the flow state. The results indicate that, as the number of valve flaps increases, the flow cross-section approaches a circular shape, reducing the number of bubbles and improving the valve flow state. When the number of valve flaps increases to 20, the flow state shows no significant difference from a circular flow cross-section. Additionally, this study investigates the impact of the valve inlet and outlet shapes on the flow state. The findings reveal that the rounded corner structure experiences severe cavitation inside and at the rear end of the valve. The chamfered corner structure generates bubbles earlier than the initial valve structure but exhibits a stronger ability to resist pressure fluctuations. Both the chamfered inlet and chamfered outlet structures help suppress cavitation, with the chamfered outlet structure exhibiting lower-pressure fluctuations and stronger cavitation resistance. Therefore, the novel cavitation regulation valve with a circular flow cross-section can effectively enhance fluid flow conditions and suppress valve cavitation, demonstrating significant engineering application value. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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29 pages, 5037 KiB

Open AccessArticle

Amalgamation of Drainage Area Ratio and Nearest Neighbors Methods for Predicting Stream Flows in British Columbia, Canada

by Muhammad Uzair Qamar, Courtney Turner and Cameron Stooshnoff

Water 2025, 17(10), 1502; https://doi.org/10.3390/w17101502 - 16 May 2025

Abstract

British Columbia, Canada, is recognized for its abundant natural resources, including agricultural and aquaculture products, sustained by its diverse climate and geography. Water resource allocation in BC is governed by the Water Sustainability Act, enacted on 29 February 2016, replacing the historic Water [...] Read more.

British Columbia, Canada, is recognized for its abundant natural resources, including agricultural and aquaculture products, sustained by its diverse climate and geography. Water resource allocation in BC is governed by the Water Sustainability Act, enacted on 29 February 2016, replacing the historic Water Act. However, limited gauging of streams across the province poses challenges for ensuring water allocation while meeting Environmental Flow Needs. Overallocated watersheds and data-scarce watersheds in need of licensing highlight the need for robust streamflow prediction methods. To address these challenges, we developed a methodology that integrates the Drainage Area Ratio and Nearest Neighbors techniques to predict streamflows efficiently, without incurring additional financial costs. We utilized Digital Elevation Models and flow data from provincially and municipally managed hydrometric stations, as well as from the Water Survey of Canada, to normalize streamflows based on area, slope, and elevation. This approach ensures hydrological predictions that account for variability in hydrological processes resulting from differences in lumped-scale watershed characteristics. The method was validated using streamflow data from hydrometric stations maintained by the aforementioned entities. For validation, each station was iteratively treated as ungauged by temporarily removing it from the dataset and then predicting its streamflow using the proposed methodologies. The results demonstrated that the amalgamated Drainage Area Ratio–Nearest Neighbors approach outperformed the traditional Drainage Area Ratio method, offering reliable predictions for diverse watersheds. This study provides an adaptable and cost-effective framework for enhancing water resource management across BC. Full article

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

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18 pages, 8912 KiB

Open AccessArticle

Experimental Study on the Motion Response Characteristics of a Floating Wind Turbine with a Semi-Submersible Foundation

by Zhipeng Zang, Haoming Zong, Zhuo Fang, Jinfeng Zhang and Cun Hu

Water 2025, 17(10), 1501; https://doi.org/10.3390/w17101501 - 16 May 2025

Abstract

In this study, a series of physical model tests were conducted in a three-dimensional wave basin to examine the motion response characteristics and stability of a floating wind turbine with a semi-submersible foundation with four columns under various conditions, including waves, combined wind [...] Read more.

In this study, a series of physical model tests were conducted in a three-dimensional wave basin to examine the motion response characteristics and stability of a floating wind turbine with a semi-submersible foundation with four columns under various conditions, including waves, combined wind and waves, and combined wind, current, and waves. The pitch response amplitude of the floating wind turbine was systematically analyzed to assess the performance of the semi-submersible foundation. The results indicate that utilizing three mooring lines affixed to the three surrounding columns, as opposed to a single mooring line attached to the central column, markedly decreases the pitch response amplitude of the floating wind turbine. Under wind-only conditions, the turbine maintains a stable inclination with a minimal degree of deviation, even when subjected to the maximum design wind load. Across the investigated range of wave periods, the pitch response amplitude shows a rising trend without reaching a peak, suggesting that the natural period of the floating wind turbine is designed to differ from the most prevalent wave periods in real ocean environments. When wave and wind loads are combined, the pitch response amplitude of the floating wind turbine is slightly reduced compared to the amplitude induced by wave load alone. This reduction is likely attributable to the increased spring constant of the mooring lines, resulting from the steady drift under wind. When wave, current, and wind loads are combined, the pitch response amplitude of a floating wind turbine closely aligns with that induced by waves only. This phenomenon occurs predominantly because the current load counterbalances the wind load relative to the center of inertia in terms of pitch response. Furthermore, the combined effect of wind and current induces a steady drift, which subsequently increases the tension in the mooring lines. Full article

(This article belongs to the Special Issue Wave–Structure Interaction in Coastal and Ocean Engineering)

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16 pages, 3488 KiB

Open AccessReview

Methodologies for Locating Suitable Areas for Rainwater Harvesting in Arid Regions: A Review

by Franco Felix Caldas Silva, Fernando António Leal Pacheco and Luís Filipe Sanches Fernandes

Water 2025, 17(10), 1500; https://doi.org/10.3390/w17101500 - 16 May 2025

Abstract

The present review article aims to address what is currently being studied in the field of identifying suitable regions for the implementation of rainwater harvesting (RWH) systems in arid zones. The need for this study is supported by the growing interest in the [...] Read more.

The present review article aims to address what is currently being studied in the field of identifying suitable regions for the implementation of rainwater harvesting (RWH) systems in arid zones. The need for this study is supported by the growing interest in the topic, which has arisen due to growing environmental concerns and the search for sustainable development techniques. Through the application of Methodi Ordinatio, 37 articles produced between 2020 and 2025 were identified. Analyzing the results, it was possible to observe the widespread use of the analytical hierarchy process (AHP) as a Multi-Criteria Analysis (MCA) methodology. To a lesser extent, the Fuzzy Analytic Hierarchy Process (FAHP) and the Weighted Linear Combination (WLC) were also used. The selected thematic layers, as well as the weights for the criteria, underwent a sensitive analysis by the researchers and may exhibit significant variation, even in studies conducted in nearby areas. The most commonly used thematic layers were slope (35 articles), land use/land cover (LULC) (28 articles), rainfall (26 articles), drainage (25 articles), and soil (25 articles). This study can be used as a methodological guide for future research and is important for the systematization of RWH studies in arid zones. Full article

(This article belongs to the Special Issue Sustainable Water Reuse and Water Economics)

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22 pages, 2172 KiB

Open AccessArticle

Insights to Estimate the Largest 1/3, 1/10, and 1/100 of Offshore Wave Heights and Periods Under Fetch-Limited Conditions in the Central Aegean Sea

by Serafeim E. Poulos, Stamatina Lesioti and Aikaterini Karditsa

Water 2025, 17(10), 1499; https://doi.org/10.3390/w17101499 - 16 May 2025

Abstract

The objective of this study is to compare the most common methods for forecasting wave characteristics (height and period) for the maximum in height 1/3, 1/10, and 1/100 of the waves, using available wind and wave datasets. The testing marine region is the [...] Read more.

The objective of this study is to compare the most common methods for forecasting wave characteristics (height and period) for the maximum in height 1/3, 1/10, and 1/100 of the waves, using available wind and wave datasets. The testing marine region is the Central Aegean Sea and, in particular, the east coast of Evia Island that is exposed to N, NE, E, and SE incoming offshore waves. The estimated values of wave characteristics resulting from three different wind datasets and the two wave datasets present differences of 2–60%. These variations are attributed to the different methodological approaches followed, to the different types of raw data in terms of space and time periods, and to the fetch limitations. The proposed methodology for the calculation of wave characteristics for the highest (1/10) and (1/100) waves appears to yield reasonable outcomes when compared to the corresponding significant (highest 1/3) wave heights and periods. Finally, mean values of wave height and period calculated from the five available datasets, considering their standard deviation, seem to be more representative than the values calculated separately from each dataset. Full article

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

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18 pages, 5072 KiB

Open AccessArticle

The Genetic Mechanism of Fluoride-Enriched Geothermal Groundwater in Southeast Coastal Areas in China: Hydrochemistry, Isotope, and Machine Learning Analysis

by Lei Liu, Shouchuan Zhang, Jiahui He and Luyao Wang

Water 2025, 17(10), 1498; https://doi.org/10.3390/w17101498 - 16 May 2025

Abstract

Fluoride-enriched geothermal groundwater poses chronic health risks (e.g., dental and skeletal fluorosis) through prolonged exposure; nevertheless, hydrochemical-driven factors and the genetic mechanism of fluoride enrichment in such systems remain inadequately identified. This study employed hydrochemical characterization, isotopic tracing, and health risk models to [...] Read more.

Fluoride-enriched geothermal groundwater poses chronic health risks (e.g., dental and skeletal fluorosis) through prolonged exposure; nevertheless, hydrochemical-driven factors and the genetic mechanism of fluoride enrichment in such systems remain inadequately identified. This study employed hydrochemical characterization, isotopic tracing, and health risk models to elucidate the genetic mechanism of fluoride-enriched geothermal groundwater. The key findings reveal the following. (1) Geothermal groundwater (Cl-Na type; TDS 90–345 mg/L; pH 6.25–7.42) contrasts with alkaline river water (pH 7.48–8.05; SO₄-Na/HCO₃-Na) and saline seawater (TDS 23.9–28.2 g/L). Stable isotopes (δD, δ¹⁸O) confirm atmospheric precipitation recharge with an elevation of 69–635 m. (2) The Self-Organizing Map algorithm categorized 30 geothermal samples into three groups: Cluster I—low temperature and pH, high TDS; Cluster II—high temperature, low F⁻ concentration; and Cluster III—low TDS, and high pH and F⁻ concentration. (3) Fluoride enrichment in Cluster III originated from the evaporite/fluorite dissolution under alkaline conditions and cation exchange interactions, while the inhibition of CaF₂ dissolution by reverse cation exchange limited the accumulation of F⁻ in Cluster II and Cluster III samples. (4) Health risks disproportionately affect children (80% high risk) and women, necessitating pre-use defluorination. Full article

(This article belongs to the Section Hydrogeology)

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21 pages, 2052 KiB

Open AccessArticle

Optimizing Oilfield-Produced Water Reuse for Sustainable Irrigation: Impacts on Soil Quality and Mineral Accumulation in Plants

by Khaled Al-Jabri, Ahmed Al-Busaidi, Mushtaque Ahmed, Rhonda R. Janke and Alexandros Stefanakis

Water 2025, 17(10), 1497; https://doi.org/10.3390/w17101497 - 16 May 2025

Abstract

The effective management of produced water (PW), a by-product of oil extraction in Oman, is essential for sustainable water use and environmental protection. PW contains petroleum residues, heavy metals, and salts, which require treatment before safe reuse. In the Nimr oil field, PW [...] Read more.

The effective management of produced water (PW), a by-product of oil extraction in Oman, is essential for sustainable water use and environmental protection. PW contains petroleum residues, heavy metals, and salts, which require treatment before safe reuse. In the Nimr oil field, PW undergoes partial treatment in constructed wetlands vegetated with buffelgrass (Cenchrus ciliaris). This study investigated the reuse potential of treated PW for irrigation through two parallel field experiments conducted at Sultan Qaboos University (SQU) and the Nimr wetlands site. At the SQU site, native halophytic plants were irrigated with three water sources: treated municipal wastewater, underground water (from an on-site well), and treated produced water. At the Nimr site, irrigation was conducted using underground water and treated PW. Two soil types were used: well-draining control soil and Nimr soil from southern Oman. The treatments included: (i) PW + control soil, (ii) PW + Nimr soil, (iii) PW + gypsum (3.5 g/kg soil), (iv) PW + biochar (10 g/kg soil), (v) underground water + control soil, and (vi) treated municipal wastewater + control soil. Biochar, produced from locally sourced buffelgrass via low-temperature pyrolysis (300 °C for 3 h), and gypsum (46.57% acid-extractable sulfate) were mixed into the soil before sowing. The impact of each treatment was assessed in terms of soil quality (salinity, boron, major cations), plant physiological responses, and mineral accumulation. PW irrigation (TDS ~ 6500–7000 mg/L) led to a sixfold increase in soil sodium and raised boron levels in plant tissues to over 200 mg/kg, exceeding livestock feed safety limits. Copper remained within acceptable thresholds (≤9.5 mg/kg). Biochar reduced boron uptake, but gypsum showed limited benefit. Neither amendment improved plant growth under PW irrigation. These findings highlight the need for regulated PW reuse, emphasizing the importance of soil management strategies and alternating water sources to mitigate salinity stress. Full article

(This article belongs to the Special Issue Effects of Hydrology on Soil Erosion and Soil Water Conservation)

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32 pages, 5449 KiB

Open AccessArticle

Energy for Water and Food: Assessing the Energy Demand of Jordan’s Main Water Conveyance System Between 2015 and 2050

by Samer Talozi, Ahmad Al-Kebsi and Christian Klassert

Water 2025, 17(10), 1496; https://doi.org/10.3390/w17101496 - 15 May 2025

Abstract

Jordan is a relatively small country with limited natural resources, but it faces a burgeoning demand for water, energy, and food to accommodate a growing population, refugee migration, and the challenges of climate change that will persist through the rest of this century. [...] Read more.

Jordan is a relatively small country with limited natural resources, but it faces a burgeoning demand for water, energy, and food to accommodate a growing population, refugee migration, and the challenges of climate change that will persist through the rest of this century. Jordan’s Main Water Conveyance System is the backbone of distributing scarce water resources to meet domestic and agricultural demands. Therefore, understanding how the future energy requirements of this system may change is critical for managing the country’s water, energy, and food resources. This paper applied a water balance model to calculate the energy consumption of Jordan’s Main Water Conveyance System between 2015 and 2050, and the results point to high energy requirements for the future of distributing Jordan’s water. In the base year of 2015, the unmet water demand was 134.55 MCM, and the supplied water volume delivered was 438.75 MCM, while the energy consumption was 1496.7 GWh. The energy intensities for water conveyance and water treatment were 7.11 kWh/m³ and 0.5 kWh/m³, respectively. We examined five scenarios of future water and energy demand within Jordan: a reference scenario, a continuation of current behavior, two scenarios incorporating improved water management strategies, and a pessimistic scenario with no interventions. According to all scenarios, the energy consumption is expected to be doubled by the year 2050, reaching approximately 3172 GWh. It is recommended that Jordan prioritizes solar-powered conveyance and pumping to reduce the projected doubling of energy demand by 2050. Across all scenarios, the demand for nonrenewable energy associated with water conveyance is projected to rise significantly, particularly in the absence of renewable integration or efficiency interventions. Total water demand is expected to increase by up to 35% by 2050, with urban and agricultural sectors being the primary contributors. Full article

(This article belongs to the Special Issue Insights on the Water–Energy–Food Nexus and Sustainable Development)

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19 pages, 4952 KiB

Open AccessArticle

Distribution Patterns and Human Exposure Risks of Microplastics in Dominant Wild Edible Shrimp: A Case Study of Haizhou Bay Marine Ranch

by Chunmei Gao, Minghe Chen, Baogui Liang, En Cai, Shuo Zhang and Shike Gao

Water 2025, 17(10), 1495; https://doi.org/10.3390/w17101495 - 15 May 2025

Abstract

“Edible wild shrimp” play a crucial role in marine ecosystems and food chains, yet research on microplastic (MP) impacts on the dominant shrimp species of the Haizhou Bay Marine Ranch remains scarce. This study examined shrimp from Haizhou Bay, evaluating the distribution, nutritional [...] Read more.

“Edible wild shrimp” play a crucial role in marine ecosystems and food chains, yet research on microplastic (MP) impacts on the dominant shrimp species of the Haizhou Bay Marine Ranch remains scarce. This study examined shrimp from Haizhou Bay, evaluating the distribution, nutritional characteristics, and health risks associated with microplastics in their tissues. Analytical techniques included Fourier transform infrared spectroscopy, the hot needle method, stable isotope analysis, and microplastic risk assessment. The results revealed that microplastics comprised 40.93% of all particles identified, with Oratosquilla oratoria exhibiting the highest intestinal contamination, followed by Alpheus distinguendus. Most MPs were fibrous (86.3%), predominantly blue (57.32%), and approximately 80% consisted of Polyethylene Terephthalate. Significant interspecies differences were observed in the gastrointestinal distribution of MPs, while individuals of the same species showed no notable differences across body-length groups due to molting. The estimated daily intake and margin of exposure for human consumers remained well below the no-observed-adverse-effect level, suggesting negligible health risks. These findings provide a theoretical and empirical basis for understanding the migration, sources, and ecological implications of microplastics in shrimp, offering valuable insights for assessing nearshore environmental pollution and food web dynamics. Full article

(This article belongs to the Section Water, Agriculture and Aquaculture)

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