Water

14 pages, 3670 KB

Open AccessArticle

Study on Natural Background Levels and Mechanisms of Groundwater Contamination in an Overexploited Aquifer Region: A Case Study of Xingtai City, North China Plain

by Qi Wang, Meili Wang, Yan Li, Binghao Guo, Hongchao Li, Yang Liu, Liya Zhao, Chunyang Ma and Ziting Yuan

Water 2025, 17(19), 2836; https://doi.org/10.3390/w17192836 (registering DOI) - 27 Sep 2025

Abstract

This study investigates the groundwater over-exploitation zone in Xingtai City, North China Plain, to address two critical gaps in the current understanding of groundwater chemistry: the lack of established natural background levels (NBLs) and the ambiguous mechanisms of groundwater contamination. Sixty shallow-groundwater samples [...] Read more.

This study investigates the groundwater over-exploitation zone in Xingtai City, North China Plain, to address two critical gaps in the current understanding of groundwater chemistry: the lack of established natural background levels (NBLs) and the ambiguous mechanisms of groundwater contamination. Sixty shallow-groundwater samples were collected and analyzed using a combination of Piper diagrams, cumulative-probability statistics, contamination-index methods, and multivariate statistical techniques to determine NBLs and threshold values (TVs) for major chemical constituents and to clarify the contamination mechanisms. The results indicate that the groundwater is weakly alkaline, with the most prevalent water types being HCO₃–Na and SO₄·Cl–Na. The NBLs for Na⁺, Ca²⁺, Mg²⁺, Cl⁻,

S O_{4}^{2 -}

and

N O_{3}^{-}

are 32.3 mg/L, 34.1 mg/L, 17.8 mg/L, 46.2 mg/L, 66.4 mg/L and 0.886 mg/L, respectively, and the corresponding TVs are 116 mg/L, 54.6 mg/L, 33.9 mg/L, 248 mg/L, 258 mg/L and 44.7 mg/L. Based on the TVs, 56.7% of the sampling sites are identified as anthropogenically contaminated. Principal component analysis reveals that groundwater over-extraction, industrial activities and water–rock interaction are the dominant drivers of groundwater contamination, whereas intensive abstraction, agricultural fertilization and domestic sewage discharge exert additional influence. The findings provide a scientific basis for pollution control and sustainable utilization of groundwater in over-exploited regions. Full article

(This article belongs to the Special Issue Pollution Mechanisms and Source Apportionment of Typical Pollutants in Aquatic Environments)

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30 pages, 1964 KB

Open AccessArticle

Water Demand and Conservation in Arid Urban Environments: Numerical Analysis of Evapotranspiration in Arizona

by Jaden Lu and Zbigniew J. Kabala

Water 2025, 17(19), 2835; https://doi.org/10.3390/w17192835 (registering DOI) - 27 Sep 2025

Abstract

Water management in arid regions, such as Arizona, is critical due to increasing demands from the urban, agricultural, and recreational sectors. In this study, Finite element analysis software COMSOL Multiphysics (COMSOL 6.3) is used to quantify water demands in Chandler, Arizona. Evapotranspiration from [...] Read more.

Water management in arid regions, such as Arizona, is critical due to increasing demands from the urban, agricultural, and recreational sectors. In this study, Finite element analysis software COMSOL Multiphysics (COMSOL 6.3) is used to quantify water demands in Chandler, Arizona. Evapotranspiration from vegetation and pools is studied. Factors are divided into environmental (temperature, humidity, wind speed) and soil-related properties (moisture content, hydraulic conductivity), which are modeled and used to estimate annual water losses. This study represents the first comprehensive investigation of the usage across several main categories at Arizona. Results indicate that pools contribute 61% of surface water evaporation. Annual water demand in Chandler for 2024 peaks at 425,000 m³ in June, with irrigation for vegetation dominating consumption. Validation against experimental data confirms model accuracy. This simulation work aims to provide scalable insights for water management in arid urban environments. Based on the simulation, various solutions were proposed to reduce water consumption and minimize water loss. Some active measures include the optimization of irrigation time and frequency based on dynamic and real-time environmental conditions. The proposed solution can help minimize the water consumption while maintaining the water demands for plant life sustenance. Other passive measures include the modification of localized environmental conditions to reduce water evaporation. In particular, it was found that fence installation can significantly change the water vapor flow and distribution close to the water surface and suppress the water evaporation by simply lowering the wind speed right above the water surface. A logical takeaway is that evaporation would also decrease when pools are built with deeper water surfaces. Full article

(This article belongs to the Special Issue Groundwater Flow and Transport Modeling in Aquifer Systems: 2nd Edition)

21 pages, 7401 KB

Open AccessArticle

Integrated Ecological Security Assessment: Coupling Risk, Health, and Ecosystem Services in Headwater Regions—A Case Study of the Yangtze and Yellow River Source

by Zhiyi Li, Jijun Xu, Zhe Yuan and Li Wang

Water 2025, 17(19), 2834; https://doi.org/10.3390/w17192834 (registering DOI) - 27 Sep 2025

Abstract

The Source Region of the Yangtze and Yellow Rivers (SRYY), situated on the Qinghai-Tibet Plateau, serves as a vital ecological barrier and a critical component of the global carbon cycle. However, this region faces severe ecosystem degradation driven by climate change and human [...] Read more.

The Source Region of the Yangtze and Yellow Rivers (SRYY), situated on the Qinghai-Tibet Plateau, serves as a vital ecological barrier and a critical component of the global carbon cycle. However, this region faces severe ecosystem degradation driven by climate change and human activities. This study establishes an integrated ecological security assessment framework that couples ecological risk, ecosystem health, and ecosystem services to evaluate ecological dynamics in the SRYY from 2000 to 2020. Leveraging multi-source data (vegetation, hydrological, meteorological) and advanced modeling techniques (spatial statistics, geographically weighted regression), we demonstrate that: (1) The Ecological Security Index (ESI) exhibited an initial increase followed by a significant decline after 2010, falling below its 2000 level by 2020. (2) The rising Ecological Risk Index (ERI) directly weakened both the ESI and Ecosystem Service Index (ESsI), with this negative effect intensifying markedly post-2010. (3) A distinct spatial gradient pattern emerged, shifting from high-security core areas in the east to low-security zones in the west, closely aligned with terrain and elevation; conversely, areas exhibiting abrupt ESI changes showed little correlation with permafrost degradation zones. (4) Vegetation coverage emerged as the key driver of ESI spatial heterogeneity, acting as the central hub in the synergistic regulation of ecological security by climate and topographic factors. Full article

(This article belongs to the Special Issue Wetland Conservation and Ecological Restoration, 2nd Edition)

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25 pages, 3431 KB

Open AccessReview

Heavy Metal Transport in Dammed Rivers: Damming Effects and Remediation Strategies—A Review

by Rong Huang, Sitong Liu, Qiusheng Yuan, Xun Wang, Lingxiao Ren, Linqian Rong and Yuting Pan

Water 2025, 17(19), 2833; https://doi.org/10.3390/w17192833 (registering DOI) - 27 Sep 2025

Abstract

Rivers, vital for life and civilizations, face severe threats from human activities such as hydropower development, with heavy metal pollution emerging as a critical concern due to altered biogeochemical cycles. Understanding how river damming affects heavy metal transport processes and developing targeted remediation [...] Read more.

Rivers, vital for life and civilizations, face severe threats from human activities such as hydropower development, with heavy metal pollution emerging as a critical concern due to altered biogeochemical cycles. Understanding how river damming affects heavy metal transport processes and developing targeted remediation strategies are essential for safeguarding the health of river-reservoir ecosystems and enabling the sustainable utilization of hydropower resources. Therefore, this review first summarizes the global hydropower development, details how damming disrupts hydrology, environments, and ecosystems, and analyzes heavy metal distribution and transport in reservoir water, suspended sediments, and riverbed sediments. It reveals that river damming promotes heavy metal adsorption onto suspended particles, deposition in riverbed sediments, and re-release during reservoir regulation, and anthropogenic activities are a primary driver of significant pollution in key reservoirs worldwide. Additionally, we further evaluate in situ (e.g., stabilizing agents, sediment capping, and phytoremediation) and ex situ (e.g., dredging, chemical washing, electrochemical separation, and ultrasonic extraction) remediation techniques, highlighting the challenges of phytoremediation in deep, stratified reservoir environments. Moreover, solidification/stabilization emerges as a promising in situ strategy, emphasizing the need for specific approaches to balance pollution control with hydropower functionality in dammed river systems. Full article

(This article belongs to the Special Issue Geochemistry and Removal of Heavy Metals and Other Pollutants in Water)

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19 pages, 5083 KB

Open AccessArticle

Integrating Fungal-Assisted Microalgal Harvesting for Sustainable Treatment and Resource Recovery from Wastewater

by Ayesha Algade Amadu, Daniel Oduro-Mensah, Shuang Qiu, Abdul-Wahab Abbew, Mengting Li, Xiyang Lu, Gabriel Komla Ameka, Mike Yaw Osei-Atweneboana, Mark Osa Akrong, Jacob Kwaku Donkor and Shijian Ge

Water 2025, 17(19), 2832; https://doi.org/10.3390/w17192832 (registering DOI) - 27 Sep 2025

Abstract

Microalgae cultivation is often limited by the high cost and inefficiency of harvesting, making it a major barrier to large-scale resource recovery. Traditional methods such as centrifugation or chemical flocculation are expensive and environmentally unsustainable. As a biological alternative, filamentous fungi can form [...] Read more.

Microalgae cultivation is often limited by the high cost and inefficiency of harvesting, making it a major barrier to large-scale resource recovery. Traditional methods such as centrifugation or chemical flocculation are expensive and environmentally unsustainable. As a biological alternative, filamentous fungi can form pellets or hyphal networks that entrap microalgae cells via bio-flocculation, facilitating easier separation from the culture medium. This study aimed to optimize culture conditions for fungal pellet formation and develop effective microalgae–fungal composites for improved harvesting. Fungal isolates including Aspergillus niger, A. fumigatus, A. flavus, and unidentified strains were screened for their pelleting capacity and nutrient removal efficiency. Through OVAT analysis, key factors such as pH, agitation speed, carbon source, and C:N ratio were found to significantly influence pellet formation. One isolate (FP) showed strong potential, forming pellets under stationary conditions and performing best at neutral to alkaline pH. Molecular analysis identified FP as a fungal consortium containing members of Ascomycota, Mucoromycota, Basidiomycota, and Rozellomycota. When applied to cocoa pulp wastewater, the microalgae–fungi composites outperformed monocultures in reducing NH₄⁺-N, COD, and PO₄³⁻-P. Interestingly, microalgae delayed fungal sporulation. These findings highlight the potential of fungal consortia in enhancing both microalgae harvesting and wastewater bioremediation. Full article

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

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23 pages, 5227 KB

Open AccessArticle

The Simulation of Sediment Transport and the Determination of the Total Volume of Alluvium Using MIKE 21 Software—Case Study: The Șolea Stream (Vâlsan Basin), Romania

by Ionuț-Mădălin Costinescu, Alexandru Nedelea, Daniela Sârbu, Maria Chevereșan and Laura Comănescu

Water 2025, 17(19), 2831; https://doi.org/10.3390/w17192831 - 26 Sep 2025

Abstract

This study presents a methodology for extracting precise insights on sediment transport in the minor bed of a watercourse using MIKE 21 hydrodynamic modelling software. By integrating geotechnical, geomorphological, and hydrological datasets with a good-resolution Digital Terrain Model (DTM), sediment quantities along a [...] Read more.

This study presents a methodology for extracting precise insights on sediment transport in the minor bed of a watercourse using MIKE 21 hydrodynamic modelling software. By integrating geotechnical, geomorphological, and hydrological datasets with a good-resolution Digital Terrain Model (DTM), sediment quantities along a 4.9 km stretch of the Șolea stream—spanning from its source to its confluence with the Vâlsan River (Argeș hydrographic basin)—were determined. A three-month simulation using MIKE 21’s “Mud Transport Module” enabled the comparison of pre- and post-simulation terrain models, yielding detailed information on sediment distribution across the riverbed. These results offer predictive capabilities regarding erosional dynamics and inform mitigation measures to address sedimentary erosion within the study area. The study also presents proposals for land reclamation necessary to prevent the degradation of the riverbed and slopes, such as gabion retaining walls and check dams in the riverbed. Full article

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

13 pages, 1173 KB

Open AccessArticle

Geochemical and Mineralogical Characterisation of Carbonate-Rich Lake Sediments from Lake Kolon, Hungary

by Tamás Zsolt Vári, Gábor Bozsó, Pál Sümegi and Elemér Pál-Molnár

Water 2025, 17(19), 2830; https://doi.org/10.3390/w17192830 - 26 Sep 2025

Abstract

The Danube–Tisza Interfluve in central Hungary, a key region for Quaternary paleoenvironmental reconstruction, hosts ephemeral saline lakes that serve as highly sensitive archives of past climate variability but are increasingly threatened by desertification. Carbonate-rich lacustrine deposits within these systems form through a complex [...] Read more.

The Danube–Tisza Interfluve in central Hungary, a key region for Quaternary paleoenvironmental reconstruction, hosts ephemeral saline lakes that serve as highly sensitive archives of past climate variability but are increasingly threatened by desertification. Carbonate-rich lacustrine deposits within these systems form through a complex interplay of biogenic CO₂ uptake and inorganic precipitation driven by evaporation. To refine paleoenvironmental reconstructions from these archives, a lacustrine sediment core was analysed using XRPD for mineralogy and XRF for major and trace element geochemistry. The results reveal four distinct environmental phases: a cold, siliciclastic-dominated Late Glacial period (c. 23,600–13,400 cal BP); an abrupt shift to massive autogenic carbonate production during the warmer Late Glacial Interstadial, which was also marked by intense aeolian activity (Zr enrichment); the development of a Holocene fen (from c. 11,200 cal BP) with fluctuating hydrology; and a recent interval (from c. 800 cal BP) showing extreme enrichment in phosphorus, lead, and sulphur from anthropogenic sources. Full article

(This article belongs to the Special Issue Carbon Storage in Lake Sediments Under Climate Change)

20 pages, 3590 KB

Open AccessArticle

Effect of Relative Wavelength on Excess Pore Water Pressure in Silty Seabeds with Different Initial Consolidation Degrees

by Hongyi Li, Yaqi Zhang, Aidong Ma, Mingzheng Wen, Zixi Zhao and Shaotong Zhang

Water 2025, 17(19), 2829; https://doi.org/10.3390/w17192829 - 26 Sep 2025

Abstract

Wave-induced silty seabed liquefaction is one of the key threats to offshore infrastructure stability. The excess pore pressure (EPP) response is the key parameter for judging seabed liquefaction. Many studies have examined the EPP response to surface waves in initially well-consolidated seabed; few [...] Read more.

Wave-induced silty seabed liquefaction is one of the key threats to offshore infrastructure stability. The excess pore pressure (EPP) response is the key parameter for judging seabed liquefaction. Many studies have examined the EPP response to surface waves in initially well-consolidated seabed; few works have explored initially less-consolidated seabed, which is widely distributed in estuaries due to the massive river sediment discharge and, thereafter, rapid accumulation. Here, we investigate the EPP response of silty seabed with various initial consolidation degrees using wave flume experiments. We found that (1) in initially liquefied seabed, the EPP magnitude monotonically increases with wavelength, while in initially consolidated seabed, there is a maximal response wavelength which is inversely related to consolidation degree. (2) Furthermore, we found two opposite EPP responses to cyclic surface wave loading under varying seabed conditions in initially liquefied and consolidated seabeds. That is, under the same waves, the EPP magnitude is inversely related to the consolidation degree in initially liquefied seabed, while the EPP magnitude is positively related to the consolidation degree in initially consolidated seabed. In other words, the influence of initial seabed consolidation degree on EPP magnitude behaves like a “√” shaped curve. Our findings provide some implications for further understandings of wave-induced silty seabed liquefaction. Full article

(This article belongs to the Special Issue Advanced Research on Marine Geology and Sedimentology)

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18 pages, 3861 KB

Open AccessArticle

Studies on the Migration of Metal Ions in the Aquifer and the Seepage Prevention of Intercepting Walls in Lead–Zinc Mining Areas

by Shuangcheng Tang, Xuehai Fu, Haiyue Lin, Zexuan Liao, Baolei Xie, Zhiwen Xue, Guanyu Zhao, Wei Qiao and Qiqing Wang

Water 2025, 17(19), 2828; https://doi.org/10.3390/w17192828 (registering DOI) - 26 Sep 2025

Abstract

As metal resource extraction increases, heavy metal ion pollution in the saturated zone intensifies. Hence, research on the migration of heavy metal ions in aquifers and the efficacy of protective measures is essential to inform pollution prevention and control engineering. This study focuses [...] Read more.

As metal resource extraction increases, heavy metal ion pollution in the saturated zone intensifies. Hence, research on the migration of heavy metal ions in aquifers and the efficacy of protective measures is essential to inform pollution prevention and control engineering. This study focuses on the slag pond and its surrounding area of a smelting plant. Utilizing field hydrological surveys and experiments, and data from previous studies, we employed FEFLOW7.0 simulation software to model the groundwater system of the boulder aquifer in this region. The model divides the domain based on natural topography: the eastern river serves as a constant-head boundary, while other areas are set as specified-flux boundaries. The impermeable layer at the bottom is treated as a no-flow boundary, with a maximum simulation period of 2500 days. The simulation examines the natural movement of zinc ions and how the construction of the wall impacts their migration, as well as the wall’s effectiveness in preventing seepage. Findings indicate that the movement of zinc ions is significantly influenced by the reaction coefficient. When the reaction coefficient exceeds 10⁻⁸ s⁻¹, zinc ions decrease rapidly in the area. After the construction of the cutoff wall, the maximum migration distance of zinc ions within 2500 days decreased from 220 m to 77 m, demonstrating its effectiveness in controlling zinc transport in groundwater. Full article

(This article belongs to the Section Hydrogeology)

18 pages, 5020 KB

Open AccessArticle

Assessment of Wetlands in Liaoning Province, China

by Yu Zhang, Chunqiang Wang, Cunde Zheng, Yunlong He, Zhongqing Yan and Shaohan Wang

Water 2025, 17(19), 2827; https://doi.org/10.3390/w17192827 - 26 Sep 2025

Abstract

In recent years, under the dual pressures of climate change and human activities, wetlands in Liaoning Province, China, are increasingly threatened, raising concerns about regional ecological security. To better understand these changes, we developed a vulnerability assessment framework integrating a 30 m wetland [...] Read more.

In recent years, under the dual pressures of climate change and human activities, wetlands in Liaoning Province, China, are increasingly threatened, raising concerns about regional ecological security. To better understand these changes, we developed a vulnerability assessment framework integrating a 30 m wetland dataset (2000–2020) with multi-source environmental and socio-economic data. Using the XGBoost–SHAP model, we analyzed wetland spatiotemporal evolution, driving mechanisms, and ecological vulnerability. Results show the following: (1) ecosystem service functions exhibited significant spatiotemporal differentiation; carbon storage has generally increased, water conservation capacity has significantly improved in the northern region, while wind erosion control and soil retention functions have declined due to urban expansion and agricultural development; (2) driving factors had evolved dynamically, shifting from population density in the early period to increasing influences of precipitation, vegetation index, GDP, and wetland area in later years; (3) ecologically vulnerable areas demonstrated a pattern of fragmented patches coexisting with zonal distribution, forming a three-level spatial gradient of ecological vulnerability—high in the north, moderate in the central region, and low in the southeast. These findings demonstrate the cascading effects of natural and human drivers on wetland ecosystems, and provide a sound scientific basis for targeted conservation, ecological restoration, and adaptive management in Liaoning Province. Full article

(This article belongs to the Special Issue Impacts of Climate Change & Human Activities on Wetland Ecosystems)

35 pages, 7061 KB

Open AccessArticle

Monitoring Surface Water Dynamics in Mining Areas Using Remote Sensing Indices: A Review and Cross-Case Analysis

by Aleksandra Smentek, Aleksandra Kaczmarek, Pinar Eksert and Jan Blachowski

Water 2025, 17(19), 2826; https://doi.org/10.3390/w17192826 - 26 Sep 2025

Abstract

Mining affects groundwater and surface water both during an active mining operation and after its termination. Continuous monitoring and both quantitative and qualitative assessment of water dynamics are crucial for the sustainable management of the mining and post-mining environment. This paper provides an [...] Read more.

Mining affects groundwater and surface water both during an active mining operation and after its termination. Continuous monitoring and both quantitative and qualitative assessment of water dynamics are crucial for the sustainable management of the mining and post-mining environment. This paper provides an extensive overview of water in the mining industry and of remote sensing methods for surface water monitoring. Moreover, selected spectral water indices are compared to assess their performance and usefulness in surface water monitoring. The Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Modified Normalized Difference Water Index (MNDWI) are applied to different case study areas affected by mining-induced multitemporal surface water changes. All the selected indices were found useful as proxies for surface water identification; however, their effectiveness and accuracy varied in subsequent case studies. Full article

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

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21 pages, 5451 KB

Open AccessArticle

Digital Economic Development Benefits Water Environmental Quality in the Yellow River Basin

by Hui Zhang, Ruining Jia, Rui Xia, Yan Chen, Kai Zhang and Junde Ming

Water 2025, 17(19), 2825; https://doi.org/10.3390/w17192825 - 26 Sep 2025

Abstract

The digital economy, as an advanced economic form, exerts a profound yet unclear influence on water environmental quality within large-scale watersheds. Focusing on the Yellow River Basin (YRB), the second-largest river in China, this study investigates this complex relationship. We developed a novel [...] Read more.

The digital economy, as an advanced economic form, exerts a profound yet unclear influence on water environmental quality within large-scale watersheds. Focusing on the Yellow River Basin (YRB), the second-largest river in China, this study investigates this complex relationship. We developed a novel dual-engine coupling model integrating Support Vector Machines (SVM) and Light Gradient Boosting Machines (LightGBM) to establish comprehensive multi-input, multi-output linkages between digital economy indicators and water quality parameters. Results show that (1) There are notable spatial disparities and synergies in the basin, regions with more developed digital economy generally have better water environmental quality. (2) The SVM model effectively captures the complex spatial relationship between digital economy inputs and water quality outputs, with an average training accuracy above 0.80 and average validation accuracy above 0.70, indicating that digital economy variables are sensitive to water quality changes. (3) The LightGBM model identifies key driving factors and contributions, revealing that digital industrialization has a more significant impact on water quality improvement than industrial digitization. Thus, digital industrialization is a crucial pathway for green transformation in large—scale catchments. Full article

(This article belongs to the Special Issue Water Environment Pollution and Control, 4th Edition)

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20 pages, 15838 KB

Open AccessArticle

The Application of Baseflow Separation and Master Recession Curves Methods in the Middle Yellow River Basins

by Haoxu Tong and Li Wan

Water 2025, 17(19), 2824; https://doi.org/10.3390/w17192824 - 26 Sep 2025

Abstract

Baseflow is the part of the groundwater aquifer that replenishes surface streamflow and is one of the main components of studying the interaction between groundwater and surface water. It is a key factor in maintaining the healthy development of basin ecosystems and is [...] Read more.

Baseflow is the part of the groundwater aquifer that replenishes surface streamflow and is one of the main components of studying the interaction between groundwater and surface water. It is a key factor in maintaining the healthy development of basin ecosystems and is of great significance for promoting the sustainable utilization and scientific management of water resources. However, the understanding of runoff and baseflow in the MYRB is still unclear, and the relationship between streamflow and baseflow has not been fully grasped. At the same time, there is currently no water balance function applicable to the MYRB. In order to solve the above problems, this article uses digital filtering methods to segment the baseflow and the MRC method to construct the main recession curve. The baseflow rate of MYRB was calculated, and the water balance function applicable to MYRB was found. The results obtained are as follows: the average annual baseflow index values for different basins were 0.81, 0.76, 0.81, 0.82, 0.79, and 0.79, respectively. The fitting of the Boussinesq function, the Maillet function, and the Brutsaert and Nieber function was significantly better than the other two functions. Full article

(This article belongs to the Section Hydrogeology)

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18 pages, 3079 KB

Open AccessArticle

Optimizing Water–Sediment, Ecological, and Socioeconomic Management in Cascade Reservoirs in the Yellow River: A Multi-Target Decision Framework

by Donglin Li, Rui Li, Gang Liu and Chang Zhang

Water 2025, 17(19), 2823; https://doi.org/10.3390/w17192823 - 26 Sep 2025

Abstract

Multi-target optimization management of reservoirs plays a crucial role in balancing multiple scheduling objectives, thereby contributing to watershed sustainability. In this study, a model was developed for the multi-target optimization scheduling of water–sediment, ecological, and socioeconomic objectives of reservoirs with multi-dimensional scheduling needs, [...] Read more.

Multi-target optimization management of reservoirs plays a crucial role in balancing multiple scheduling objectives, thereby contributing to watershed sustainability. In this study, a model was developed for the multi-target optimization scheduling of water–sediment, ecological, and socioeconomic objectives of reservoirs with multi-dimensional scheduling needs, including flood control, sediment discharge, ecological protection, and socio-economic development. After obtaining the Pareto solution set by solving the optimization model, a decision model based on cumulative prospect theory (CPT) was constructed to select optimal scheduling schemes, resulting in the development of a multi-target decision framework for reservoirs. The proposed framework not only mitigates multi-target conflicts among water–sediment, ecological, and socioeconomic objectives but also quantifies the different preferences of decision-makers. The framework was then applied to six cascade reservoirs (Longyangxia, Liujiaxia, Haibowan, Wanjiazhai, Sanmenxia, and Xiaolangdi) in the Yellow River basin of China. A whole-river multi-target decision model was developed for water–sediment, ecological, and socioeconomic objectives, and the cooperation–competition dynamics among multiple objectives and decision schemes were analyzed for wet, normal, and dry years. The results demonstrated the following: (1) sediment discharge goals and ecological goals were somewhat competitive, and sediment discharge goals and power generation goals were highly competitive, while ecological goals and power generation goals were cooperative, and cooperation–competition relationships among the three objectives was particularly pronounced in dry years; (2) the decision plans for abundant, normal, and low water years were S293, S241, and S386, respectively, and all are consistent with actual dispatch conditions; (3) compared to local models, the whole-river multi-target scheduling model achieved increases of 71.01 × 10⁶ t in maximum sediment discharge, 0.72% in maximum satisfaction rate of suitable ecological flow, and 0.20 × 10⁹ kW·h in maximum power generation; and (4) compared to conventional decision methods, the CPT-based approach yielded rational results with substantially enhanced sensitivity, indicating its suitability for selecting and decision-making of various schemes. This study provides insights into the establishment of multi-target dispatching models for reservoirs and decision-making processes for scheduling schemes. Full article

(This article belongs to the Special Issue Yellow River Basin Management Under Pressure: Present State, Restoration and Protection, 4th Edition)

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22 pages, 6065 KB

Open AccessArticle

A Sustainability Evaluation of Large-Scale Water Network Projects: A Case Study of the Jiaodong Water Network Project, China

by Yue Qiu and Changshun Liu

Water 2025, 17(19), 2822; https://doi.org/10.3390/w17192822 - 26 Sep 2025

Abstract

Large-scale water network projects are a crucial approach for the rational allocation of water resources and addressing water resource crises. Reliable sustainability evaluation is essential to ensure the sustainable operation of large-scale water network projects. This study develops an improved Fuzzy Comprehensive Evaluation [...] Read more.

Large-scale water network projects are a crucial approach for the rational allocation of water resources and addressing water resource crises. Reliable sustainability evaluation is essential to ensure the sustainable operation of large-scale water network projects. This study develops an improved Fuzzy Comprehensive Evaluation (FCE) method based on Game Theory weight fusion (GWF) for the quantitative evaluation of the sustainability of water network projects. By combining the Analytic Hierarchy Process (AHP), Entropy Weight Method (EWM), and Game Theory approach, the study integrates the advantages of both subjective and objective weighting methods to achieve the allocation of indicator weights; the sustainability of the Jiaodong Water Network Project was quantitatively evaluated by employing the improved FCE method. The results indicate that the resource and management dimensions are the two most critical factors affecting the sustainability of large-scale water network projects. Indicators with high weight such as per capita water resources, the rationality of the management system, and level of management intelligence are the primary risk factors affecting the sustainable operation of large-scale water network projects. The sustainability evaluation value of the Jiaodong Water Network Project is 82.83 points, which is classified as “high” sustainability. This validates the reliability of the evaluation indicator system and the method used. Full article

(This article belongs to the Section Hydrology)

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19 pages, 5264 KB

Open AccessArticle

Integrated Allocation of Water-Sediment Resources and Its Impacts on Socio-Economic Development and Ecological Systems in the Yellow River Basin

by Lingang Hao, Enhui Jiang, Bo Qu, Chang Liu, Jia Jia, Ying Liu and Jiaqi Li

Water 2025, 17(19), 2821; https://doi.org/10.3390/w17192821 - 26 Sep 2025

Abstract

Both water and sediment resource allocation are critical for achieving sustainable development in sediment-laden river basins. However, current understanding lacks a holistic perspective and fails to capture the inseparability of water and sediment. The Yellow River Basin (YRB) is the world’s most sediment-laden [...] Read more.

Both water and sediment resource allocation are critical for achieving sustainable development in sediment-laden river basins. However, current understanding lacks a holistic perspective and fails to capture the inseparability of water and sediment. The Yellow River Basin (YRB) is the world’s most sediment-laden river, characterized by pronounced ecological fragility and uneven socio-economic development. This study introduces integrated water-sediment allocation frameworks for the YRB based on the perspective of the water-sediment nexus, aiming to regulate their impacts on socio-economic and ecological systems. The frameworks were established for both artificial units (e.g., irrigation zones and reservoirs) and geological units (e.g., the Jiziwan region, lower channels, and estuarine deltas) within the YRB. The common feature of the joint allocation of water and sediment across the five units lies in shaping a coordinated water–sediment relationship, though their focuses differ, including in-stream water-sediment processes and combinations, the utilization of water and sediment resources, and the constraints imposed by socio-economic and ecological systems on water-sediment distribution. In irrigation zones, the primary challenge lies in engineering-based control of inflow magnitude and spatiotemporal distribution for both water and sediment. In reservoir systems, effective management requires dynamic regulation through density current flushing and coordinated operations to achieve water-sediment balance. In the Jiziwan region, reconciling socio-economic development with ecological integrity requires establishing science-based thresholds for water and sediment use while ensuring a balance between utilization and protection. Along the lower channel, sustainable management depends on delineating zones for human activities and ecological preservation within floodplains. For deltaic systems, key strategies involve adjusting upstream sediment and refining depositional processes. Full article

(This article belongs to the Special Issue Resilient Rivers: Integrating Nature-Based Solutions with Hydraulic Engineering)

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58 pages, 4032 KB

Open AccessArticle

Potential Applications of Light Absorption Coefficients in Assessing Water Optical Quality: Insights from Varadero Reef, an Extreme Coral Ecosystem

by Stella Patricia Betancur-Turizo, Adán Mejía-Trejo, Eduardo Santamaria-del-Angel, Yerinelys Santos-Barrera, Gisela Mayo-Mancebo and Joaquín Pablo Rivero-Hernández

Water 2025, 17(19), 2820; https://doi.org/10.3390/w17192820 - 26 Sep 2025

Abstract

Coral reefs exposed to chronically turbid conditions challenge conventional assumptions about the optical environments required for reef persistence and productivity. This study investigates the utility of light absorption coefficients as indicators of optical water quality in Varadero Reef, an extreme coral ecosystem located [...] Read more.

Coral reefs exposed to chronically turbid conditions challenge conventional assumptions about the optical environments required for reef persistence and productivity. This study investigates the utility of light absorption coefficients as indicators of optical water quality in Varadero Reef, an extreme coral ecosystem located in Cartagena Bay, Colombia. Field campaigns were conducted across three seasons (rainy, dry, and transitional) along a transect from fluvial to marine influence. Absorption coefficients at 440 nm were derived for particulate (a_p(440)) and chromophoric dissolved organic matter (a_CDOM(440)) to assess their contribution to underwater light attenuation. Average values across seasons show that a_p(440) reached 0.466 m⁻¹ in the rainy season (September 2021), 0.285 m⁻¹ in the dry season (February 2022), and 0.944 m⁻¹ in the transitional rainy season (June 2022). Meanwhile, mean a_CDOM(440) values were 0.368, 0.111, and 0.552 m⁻¹, respectively. These coefficients reflect the dominant influence of particulate absorption under turbid conditions and increasing a_CDOM(440) relevance during lower turbidity periods. Mean Secchi Disk Depth (ZSD) ranged from 0.6 m in the rainy season to 3.0 m in the dry season, aligning with variations in Kd PAR, which averaged 2.63 m⁻¹, 1.13 m⁻¹, and 1.08 m⁻¹ for the three campaigns. Chlorophyll-a concentrations at 1 m depth also varied significantly, with average values of 2.3, 2.7, and 6.2 μg L⁻¹, indicating phytoplankton biomass peaks associated with seasonal freshwater inputs. While particulate absorption limits light penetration, CDOM plays a potentially photoprotective role by attenuating UV radiation. The observed variability in these optical constituents reflects complex hydrodynamic and environmental gradients, providing insight into the mechanisms that sustain coral functionality under suboptimal light conditions. The absorption-based approach applied here, using standardized spectrophotometric methods, proved to be a reliable and reproducible tool for characterizing the spatial and temporal variability of IOPs. We propose integrating these indicators into monitoring frameworks as cost-effective, component-resolving tool for evaluating light regimes and ecological resilience in optically dynamic coastal systems. 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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29 pages, 1446 KB

Open AccessReview

Review of Water Use Assessment in Livestock Production Systems and Supply Chains

by Katrin Drastig and Ranvir Singh

Water 2025, 17(19), 2819; https://doi.org/10.3390/w17192819 - 25 Sep 2025

Abstract

Improving the water productivity and sustainability of global food supplies and reducing water stress worldwide requires a comprehensive and consistent assessment of water use in global food production systems, including livestock production and supply chains. Presented here is a systematic review of relevant [...] Read more.

Improving the water productivity and sustainability of global food supplies and reducing water stress worldwide requires a comprehensive and consistent assessment of water use in global food production systems, including livestock production and supply chains. Presented here is a systematic review of relevant livestock water use studies, published over two periods: “Period 1993–2017” and “Period 2018–2024”, assessing consistency in their approaches and identifying opportunities for advancing and harmonizing the assessment of livestock water use worldwide. However, the review highlights that a comprehensive and consistent assessment of livestock water use remains a challenge. The reviewed studies (a total of 317) differ in terms of their accounting of different water flows, setting the system boundaries, and quantification of water productivity and impact metrics. This makes it difficult to compare potential water productivity and environmental impacts of livestock production systems at different scales and locations. Case studies are required to further develop and implement a robust and consistent methodological approach, based on locally calibrated models and databases, of different livestock production systems in different agroclimatic conditions. Also, further communication and training are required to help build the capability to apply a comprehensive and consistent assessment of livestock water use locally and globally. The adoption of a scientifically robust and practically applicable methodological framework will support researchers, policy managers, farmers, and business leaders in sound decision-making to improve the productivity and sustainability of water use in livestock production systems locally and globally. Full article

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

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19 pages, 4745 KB

Open AccessBrief Report

Optimizing Shrimp Culture Through Environmental Monitoring: Effects of Water Quality and Metal Ion Profile on Whiteleg Shrimp (Litopenaeus vannamei) Performance in a Semi-Intensive Culture Pond

by Muhammad Farhan Nazarudin, Mohammad Amirul Faiz Zulkiply, Muhammad Hasif Samsuri, Nurul Aina Syakirah Khairil Anwar, Nur Syamimie Afiqah Jamal, Norfarrah Mohamed Alipiah, Mohd Ihsanuddin Ahmad, Norhariani Mohd Nor, Ina Salwany Md Yasin, Natrah Ikhsan, Mohammad Noor Amal Azmai and Mohd Hafiz Rosli

Water 2025, 17(19), 2818; https://doi.org/10.3390/w17192818 (registering DOI) - 25 Sep 2025

Abstract

Water quality management is crucial for sustainable whiteleg shrimp (Litopenaeus vannamei) aquaculture, though little research has comprehensively investigated the spatiotemporal fluctuation of trace elements in tropical semi-intensive ponds. This study investigated the water quality variations and trace element concentrations in an [...] Read more.

Water quality management is crucial for sustainable whiteleg shrimp (Litopenaeus vannamei) aquaculture, though little research has comprehensively investigated the spatiotemporal fluctuation of trace elements in tropical semi-intensive ponds. This study investigated the water quality variations and trace element concentrations in an earthen pond across a 56-day culture cycle during the dry season. Physicochemical parameters (temperature, pH, salinity, dissolved oxygen, ammonia, nitrite, and nitrate) and trace elements (Cu, Zn, Mn, Fe, and Mg) were measured concurrently with shrimp growth and survival. The DO and pH readings were observed to fluctuate significantly during the mid-to-late stages of culture, with DO nearing critical thresholds (<5.0 mg L⁻¹). A sudden increase in ammonia and nitrite levels suggested the accumulation of organic matter and a microbial imbalance. Zinc concentrations (0.28–1.00 mg L⁻¹) approached stress-inducing levels, while magnesium remained low (10.44–10.72 mg L⁻¹). Pearson’s correlation revealed strong positive associations between ammonia and nitrate (r = 0.95) and between DO and pH (r = 0.94), while Mg was negatively correlated with Fe (r = −0.99) and nitrite (r = −0.88). Shrimp achieved 13.43 ± 0.73 g mean weight, with 77.8% survival and an FCR of 1.08. These results provide baseline evidence that combined water quality and trace element monitoring can become an early warning framework for pond management. Future studies integrating shrimp physiology and immune responses are needed to establish direct causal relationships. Full article

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

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