Water

28 pages, 3006 KB

Open AccessArticle

Surface Water–Groundwater Interactions in a Sahelian Catchment: Exploring Hydrochemistry and Isotopes and Implications for Water Quality Management

by Issoufou Ouedraogo, Marnik Vanclooster, Frederic Huneau, Yuliya Vystavna, Seifu Kebede and Youssouf Koussoubé

Water 2025, 17(18), 2756; https://doi.org/10.3390/w17182756 - 17 Sep 2025

Abstract

The Sahel Transboundary Taoudéni Basin, covering about 20% of Burkina Faso, hosts vital aquifers critical for water security and development. Effective groundwater monitoring is essential for sustainable resource management. In the Kou sub-basin, groundwater quality assessment is increasingly important. This study integrates hydrochemistry, [...] Read more.

The Sahel Transboundary Taoudéni Basin, covering about 20% of Burkina Faso, hosts vital aquifers critical for water security and development. Effective groundwater monitoring is essential for sustainable resource management. In the Kou sub-basin, groundwater quality assessment is increasingly important. This study integrates hydrochemistry, water stable isotopes (δ¹⁸O, δ²H), GIS, and multivariate statistics to understand subsurface geochemical processes. A total of 48 samples—43 groundwater and 5 surface water—were analyzed for 19 hydrochemical parameters and isotopes. In surface water, δ¹⁸O ranged from −5.96‰ to −5.09‰, and δ²H from −37.65‰ to −29.15‰. In groundwater, δ¹⁸O ranged from −5.93‰ to −4.39‰, and δ²H from −34.62‰ to −25.05‰. The spatial distribution of δ¹⁸O and δ²H was mapped using inverse distance weighted (IDW) interpolation in ArcGIS 10.8. A δ²H vs. δ¹⁸O plot showed groundwater values clustered near the Global Meteoric Water Line, indicating minimal evaporation during recharge. Groundwater chemistry was dominated by Ca²⁺ > Na⁺ > Mg²⁺ > K⁺ and HCO₃⁻ > NO₃⁻ > Cl⁻ > SO₄²⁻. Key hydrogeochemical processes include water–rock interaction (leaching, weathering, ion exchange) and anthropogenic pollution. Isotopic signatures reveal heterogeneous recharge sources and aquifer connectivity. These findings enhance the understanding of water sources and geochemical processes in the Kou basin, supporting informed groundwater resource management. Full article

(This article belongs to the Special Issue Soil and Groundwater Quality and Resources Assessment, 2nd Edition)

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30 pages, 13114 KB

Open AccessArticle

A Pragmatic Multi-Source Remote Sensing Framework for Calcite Whitings and Post-Wildfire Effects in the Gadouras Reservoir

by John S. Lioumbas, Aikaterini Christodoulou, Alexandros Mentes, Georgios Germanidis and Nikolaos Lymperopoulos

Water 2025, 17(18), 2755; https://doi.org/10.3390/w17182755 - 17 Sep 2025

Abstract

The Gadouras Reservoir, Rhodes Island’s primary water source, experiences recurrent whiting events—milky turbidity from calcium carbonate precipitation—that challenge treatment operations, with impacts compounded by a major 2023 wildfire in this fire-prone Mediterranean setting. To elucidate these dynamics, a pragmatic, multi-source monitoring framework integrates [...] Read more.

The Gadouras Reservoir, Rhodes Island’s primary water source, experiences recurrent whiting events—milky turbidity from calcium carbonate precipitation—that challenge treatment operations, with impacts compounded by a major 2023 wildfire in this fire-prone Mediterranean setting. To elucidate these dynamics, a pragmatic, multi-source monitoring framework integrates archived Sentinel-2 and Landsat imagery with treatment-plant records (2017–mid-2025). Unitless spectral indices (e.g., AreaBGR) for whiting detection and chlorophyll-a proxies are combined with laboratory measurements of turbidity, pH, total organic carbon, manganese, and hydrological metrics, analyzed via spatiotemporal Hovmöller diagrams, Pearson correlations, and interrupted time-series models. Two seasonal whiting regimes are identified: a biogenic summer mode (southern origin; elevated chlorophyll-a; water temperature > 15 °C; pH > 8.5) and a non-biogenic winter mode (northern inflows). Following the wildfire, the system exhibits characteristics that could be related to possible hypolimnetic anoxia, prolonged whiting, a ~50% rise in organic carbon, and a manganese excursion to ~0.4 mg L⁻¹ at the deeper intake. Crucially, the post-fire period shows a decoupling of AreaBGR from turbidity (r ≈ 0.233 versus ≈ 0.859 pre-fire)—a key diagnostic finding that confirms a fundamental shift in the composition and optical properties of suspended particulates. The manganese spike is best explained by the confluence of a wildfire-induced biogeochemical predisposition (anoxia and Mn mobilization) and a consequential operational decision (relocation to a deeper, Mn-rich intake). This framework establishes diagnostic baselines and thresholds for managing fire-impacted reservoirs, supports the use of remote sensing in data-scarce systems, and informs adaptive operations under increasing climate pressures. Full article

(This article belongs to the Special Issue Remote Sensing of Spatial-Temporal Variation in Surface Water)

22 pages, 3981 KB

Open AccessArticle

Combined Efficacy of Silver, Copper, and Hypochlorite Ions for Vector Control of Juvenile Aedes aegypti in Household Water Storage Containers

by Sydney S. Turner, James A. Smith, Karin Brett, Patrick I. Hancock, Sophie L. Howle, Victoria Cecchetti, Lorin M. Bruno, Julia Davis and Clay Ford

Water 2025, 17(18), 2754; https://doi.org/10.3390/w17182754 - 17 Sep 2025

Abstract

This study evaluates the larvicidal effects of three common water disinfectants, silver (AgNO₃), copper (CuSO₄·5H₂O), and hypochlorite (NaOCl) ions. The treatments were combined at 40–50% of their recommended drinking water guidelines and tested against late first instar [...] Read more.

This study evaluates the larvicidal effects of three common water disinfectants, silver (AgNO₃), copper (CuSO₄·5H₂O), and hypochlorite (NaOCl) ions. The treatments were combined at 40–50% of their recommended drinking water guidelines and tested against late first instar and third instar Ae. aegypti larvae. The findings demonstrate that the combined application of water disinfectants yields greater efficacy in suppressing the emergence of Aedes aegypti compared to the use of the individual disinfectants alone. The silver (Ag) and copper (Cu) combination treatment (40 ppb Ag + 600 ppb Cu) showed the greatest efficacy, achieving nearly complete inhibition of emergence of the older instar larvae (98.52% [96.50, 99.47]). All treatments demonstrated high efficacy against late 1st instar Ae. aegypti larvae, with the combined copper and chlorine (Cl) treatment yielding the lowest survival rates, though individual disinfectants also produced substantial mortality. The results of this study provide critical insights to inform the design and implementation of point-of-use water treatment technologies for household water storage containers that both ensure safe drinking water and also strategically target mosquito breeding within household storage containers, thus supporting integrated vector management approaches essential for controlling neglected tropical diseases. Full article

(This article belongs to the Topic Sustainable Water Purification Technologies for Multiple Applications)

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19 pages, 2931 KB

Open AccessArticle

Integrating Microbial Source Tracking to Unravel Impacts of Wastewater Discharge on Spatial Distribution of Riverine Microbial Community

by Yanru Fan, Hongbin Gao, Zhongfeng Jiang, Yuran Lv, Xiang Guo, Xinfeng Zhu, Junfeng Wu, Yizhe Li, Wenxiang Yu, Qi Li and Keyu Yuan

Water 2025, 17(18), 2753; https://doi.org/10.3390/w17182753 - 17 Sep 2025

Abstract

Microbial communities play a pivotal role in material cycling, energy flow, and pollutant degradation within river ecosystems. Thus, gaining a clear understanding of how wastewater discharge affects microbial community structure and function is essential for the protection and management of the surface water [...] Read more.

Microbial communities play a pivotal role in material cycling, energy flow, and pollutant degradation within river ecosystems. Thus, gaining a clear understanding of how wastewater discharge affects microbial community structure and function is essential for the protection and management of the surface water environment. In this study, a total of 9 samples were collected from the Sha River in March 2024. Subsequently, 16S rRNA sequencing technology combined with investigation of physicochemical properties of water was used to investigate the compositional diversity, spatial distribution, and explore the environmental effects of wastewater discharged on microorganisms. The sequencing results of species at the phylum level revealed that the dominant microbial phyla in the Sha River were primarily Proteobacteria (55.4%), Actinobacteriota (24.0%), Bacteroidota (14.3%), and Verrucomicrobiota (2.6%). The most dominant phylum, Proteobacteria, exhibited varying abundances across different sampling sites in the Sha River basin, with the highest abundances observed at Sites S2, S4, S5, and S6. This is mainly due to the fact that the upstream areas of Sites S2, S4, S5, and S6 are characterized by high concentrations of COD and NH₃-N, which are caused by wastewater discharge. Quantitative analysis was also conducted using the Source Tracker model; the results showed that S2 (36.7%) and S4 (31.3%) in the upper reaches of the Sha River are the primary contributors to the microbial community in the downstream catchment area (S6). The study found that the impact of wastewater discharge on the microbial community in the downstream water body exhibits a “longitudinal persistence of microbial signatures” even though the physicochemical pollution indicators of the water body have decreased. These findings of this study represent the application in microbial source tracking in the upstream and downstream sections of rivers, providing strong support for formulating more effective environmental protection strategies in the Sha River basin. Full article

(This article belongs to the Special Issue Freshwater Ecosystems—Biodiversity and Protection: 2nd Edition)

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24 pages, 11507 KB

Open AccessReview

A Review on Ecological and Environmental Impacts of Pumped Hydro Storage Based on CiteSpace Analysis

by Hailong Yin, Xuhong Zhao, Meixuan Chen, Zeding Fu, Yingchun Fang, Hui Wang, Meifang Li, Jiahao Luo, Peiyang Tan and Xiaohua Fu

Water 2025, 17(18), 2752; https://doi.org/10.3390/w17182752 - 17 Sep 2025

Abstract

This study conducted a systematic review of 222 research articles (2014–2024) from the Web of Science Core Collection database to investigate the ecological and environmental impacts of pumped hydro storage (PHS). Utilizing CiteSpace 6.1R software for visual analysis, the research hotspots and evolutionary [...] Read more.

This study conducted a systematic review of 222 research articles (2014–2024) from the Web of Science Core Collection database to investigate the ecological and environmental impacts of pumped hydro storage (PHS). Utilizing CiteSpace 6.1R software for visual analysis, the research hotspots and evolutionary trends over the past decade were comprehensively examined. Key findings include the following: (1) Annual publication output exhibited sustained growth, with China contributing 29.7% of total publications, ranking first globally. (2) Research institutions demonstrated broad geographical distribution but weak collaborative networks, as the top 10 institutions accounted for only 21.6% of total publications, highlighting untapped potential for cross-regional cooperation. (3) Current research focuses on three domains: ecological–environmental benefit assessment, renewable energy synergistic integration, and power grid regulation optimization. Emerging trends emphasize multi-objective planning (e.g., economic–ecological trade-offs) and hybrid system design (e.g., solar–wind–PHS coordinated dispatch), providing critical support for green energy transitions. (4) Post-2020 research has witnessed novel thematic directions, including deepened studies on wind–PHS coupling and life-cycle assessment (LCA). Policy-driven renewable energy integration research entered an explosive growth phase, with PHS–photovoltaic–wind complementary technologies emerging as a core innovation pathway. Future research should prioritize strengthening institutional collaboration networks, exploring region-specific ecological impact mechanisms, and advancing policy–technology–environment multi-dimensional frameworks for practical applications. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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18 pages, 2468 KB

Open AccessArticle

Enhanced Nitrogen Removal from Aquaculture Wastewater Using Biochar-Amended Bioretention Systems

by Wenqiang Jiang, Xueming Yang, Chengcai Zhang, Qian Qian, Zhen Liang, Junneng Liang, Luting Wen, Linyuan Jiang and Shumin Wang

Water 2025, 17(18), 2751; https://doi.org/10.3390/w17182751 - 17 Sep 2025

Abstract

Aquaculture wastewater is characterized by large discharge volumes and variable nitrogen concentrations, posing challenges for stable and efficient treatment. This study investigated biochar-amended bioretention systems (BBSs) under varying temperatures (8.0–26.0 °C), influent TN levels, and operation modes (intermittent and continuous flow). In intermittent [...] Read more.

Aquaculture wastewater is characterized by large discharge volumes and variable nitrogen concentrations, posing challenges for stable and efficient treatment. This study investigated biochar-amended bioretention systems (BBSs) under varying temperatures (8.0–26.0 °C), influent TN levels, and operation modes (intermittent and continuous flow). In intermittent runs, the 20% biochar system (BBS20) achieved 72.4% TN removal at low influent TN (9.55 mg/L) and 80.4% at high TN (29.96 mg/L), significantly outperforming the control (CBS). In continuous runs, BBS20 reduced effluent TN to 1.75 mg/L within 72 h, yielding higher average HRT, HLR, and ELR than CBS. Mechanistic analyses showed that biochar addition enhanced extracellular polymeric substance (EPS) secretion, stimulated electron transport system activity (ETSA), and increased the relative abundance of denitrifying genera and functional genes (e.g., nirS, narG). These synergistic effects optimized nitrification–denitrification coupling, particularly under low-temperature conditions. The findings demonstrate that biochar amendment is a practical and effective strategy for improving nitrogen removal from aquaculture wastewater. Full article

(This article belongs to the Special Issue Applications of Nanozymes and Other Nanomaterials in the Water Environment: Latest Advances and Prospects)

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23 pages, 1283 KB

Open AccessArticle

An Integrated Water Resources Solution for a Wide Arid to Semi-Arid Urbanized Coastal Tropical Region with Several Topographic Challenges—A Case Study

by António Freire Diogo and António Luís Oliveira

Water 2025, 17(18), 2750; https://doi.org/10.3390/w17182750 - 17 Sep 2025

Abstract

Pressure on fresh water resources has been aggravated in recent decades, basically due to population growth, rapid urbanization, and global warming. Integrated engineering solutions and the circular economy, considering the urban water cycle as a whole, are becoming fundamental, particularly in arid and [...] Read more.

Pressure on fresh water resources has been aggravated in recent decades, basically due to population growth, rapid urbanization, and global warming. Integrated engineering solutions and the circular economy, considering the urban water cycle as a whole, are becoming fundamental, particularly in arid and semi-arid regions under permanent or recurrent hydric deficit. This study aims to develop and present an integrated engineering solution for water supply, wastewater collection, and treated wastewater reuse for landscape irrigation in a large, topographically complex, and arid to semi-arid coastal urban region at the south of Santiago Island, Cape Verde. The region is one of the driest and most arid of the Island, with a current average annual precipitation between about 100 and 200 mm, and has very limited underground water resources. The main study area, with about 600 ha, has altitudes ranging from values close to sea level up to about 115 m and has several topographic difficulties, including several relatively rugged zones. The devised water supply system considers four altimetric distribution levels, three main reservoirs connected to each other by a serial system of pipelines with successive pumping, a fourth downstream reservoir for pressure balance in one of the levels, and desalinated water as the source. The sanitary sewer pipes of the urbanizations drain to an interceptor system that operates predominantly in open channel flow in a closed pipe. The long interceptor crosses laterally along the coast several very dug valleys in the path to the Praia Wastewater Treatment Plant in the east, and requires several conduits working under pressure for the crossings, either lifting or governed by gravity. The under-pressure pipeline system of recycled water is partially forced and partially ruled by gravity and transports the treated wastewater from the plant in the opposite direction of the interceptor to a natural reservoir or lake located in the region of urbanizations and the main green spaces to be irrigated. The conceived design of the interceptor and recycled water pipeline minimizes the construction and operation costs, maximizing their hydraulic performance. Full article

(This article belongs to the Special Issue Research on Water Supply Systems and on the Treatment and Recovery of Wastewater and Stormwater)

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28 pages, 26985 KB

Open AccessArticle

Analysis of Glacial Morphological Characteristics in Ányêmaqên Mountains Using Multi-Source Time-Series High-Resolution Remote Sensing Imagery

by Wei Xu, Gang Chen, Xiaotian Wu, Delin Li, Yuhui Mao and Xin Zhang

Water 2025, 17(18), 2749; https://doi.org/10.3390/w17182749 - 17 Sep 2025

Abstract

Since the 1990s, glaciers in the Ányêmaqên Mountains of the Qinghai–Tibet Plateau have exhibited anomalous retreat and thinning. This persistent deglaciation has triggered secondary disasters including glacial debris flows, ice collapses, and glacial lake outburst floods, posing significant threats to regional ecological security [...] Read more.

Since the 1990s, glaciers in the Ányêmaqên Mountains of the Qinghai–Tibet Plateau have exhibited anomalous retreat and thinning. This persistent deglaciation has triggered secondary disasters including glacial debris flows, ice collapses, and glacial lake outburst floods, posing significant threats to regional ecological security and sustainable socioeconomic development. To address this issue, we conducted a comprehensive analysis of glacial morphological characteristics using multi-source time-series high-resolution remote sensing imagery spanning 2013–2024. Glacier boundaries were extracted through integrated methodologies combining manual visual interpretation, band ratio thresholding, three-dimensional geomorphic analysis, and an optimized DeepLabV3+ convolutional neural network with adaptive activation thresholds. Extraction accuracy was rigorously validated using quantitative metrics (Accuracy, Precision, Recall, Loss, and F1-score). Key findings reveal the following: dominant glacier types include ice caps, valley glaciers, and hanging glaciers distributed at mean elevations of 5200–5600 m; total glacial area decreased from 102.71 km² to 81.10 km², yielding an average annual decrease rate of −1.93%; glacier count increased from 74 to 86, corresponding to a mean relative change rate of 1.18% per annum; and thirty-eight geohazard sites were identified predominantly on upper slopes (30–50°) of north-facing terrain, with elevations ranging from 4500–5400 m (base) to 5120–6050 m (crest). These results provide critical data support for enhancing ecological resilience, strengthening disaster mitigation capabilities, and safeguarding public safety and infrastructure against climate change impacts in the region. Full article

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

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20 pages, 1389 KB

Open AccessArticle

Potable Water Savings Potential Through Rainwater Harvesting in a Brazilian Fitness Centre: A Case Study

by Higino Ilson da Silva, Andréa Teston, Igor Catão Martins Vaz and Enedir Ghisi

Water 2025, 17(18), 2748; https://doi.org/10.3390/w17182748 - 17 Sep 2025

Abstract

Water scarcity and rising urban demand pose growing challenges for sustainable water management in Brazil, where over 73 million people may face shortages by 2035. Given this scenario, rainwater utilisation has emerged as a strategic alternative for preserving water resources, helping to reduce [...] Read more.

Water scarcity and rising urban demand pose growing challenges for sustainable water management in Brazil, where over 73 million people may face shortages by 2035. Given this scenario, rainwater utilisation has emerged as a strategic alternative for preserving water resources, helping to reduce potable water consumption and relieving demand on public supply systems. This study aimed to evaluate the potential for potable water savings through the implementation of a rainwater harvesting system in a fitness centre without a swimming pool, located in southern Brazil—a building typology rarely addressed in the literature. Water end-uses were empirically characterised using water flow measurements and questionnaires conducted in an existing facility operated by the same franchise. A daily balance simulation was performed using the Netuno computer programme (Version 4), and an economic feasibility assessment was conducted based on local costs and tariff structures. The results showed that non-potable end-uses represented 24.4% of total water consumption. The rainwater harvesting simulation indicated an ideal tank capacity of 11,000 L, enabling potable water savings of 7.04%. The economic analysis showed an implementation cost of R$13,240.72 and a consequent return on investment of fifteen months. These findings confirm the technical and economic viability of rainwater harvesting systems for fitness centres and highlight the relevance of local conditions in shaping performance and investment returns. Full article

(This article belongs to the Section Urban Water Management)

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28 pages, 6560 KB

Open AccessArticle

SPI-Informed Drought Forecasts Integrating Advanced Signal Decomposition and Machine Learning Models

by Anwar Ali Aldhafeeri, Mumtaz Ali, Mohsin Khan and Abdulhaleem H. Labban

Water 2025, 17(18), 2747; https://doi.org/10.3390/w17182747 - 17 Sep 2025

Abstract

Drought is an extremely terrifying environmental calamity, causing declining agricultural production, escalating food prices, water scarcity, soil erosion, increased wildfire risks, and changes in ecosystem. Drought data is noisy and poses challenges to accurate forecasts due to it being nonstationary and non-linear. This [...] Read more.

Drought is an extremely terrifying environmental calamity, causing declining agricultural production, escalating food prices, water scarcity, soil erosion, increased wildfire risks, and changes in ecosystem. Drought data is noisy and poses challenges to accurate forecasts due to it being nonstationary and non-linear. This research aims to construct a contemporary and novel approach termed as TVFEMD-GPR, crossbreeding time varying filter-based empirical mode decomposition (TVFEMD) and gaussian process regression (GPR), to model multi-scaler standardized precipitation index (SPI) to forecast droughts. At first, the statistically significant lags at (t − 1) were computed via partial auto-correlation function (PACF). In the second step, the TVFEMD splits the (t − 1) lag into several factors named as intrinsic mode functions (IMFs) and residual components. The third step is the final step, where the GPR model took the IMFs and residual as input predictors to forecast one-month SPI (SPI1), three-months SPI (SPI3), six-months SPI (SPI6), and twelve-months SPI1 (SPI12) for Mackay and Springfield stations in Australia. To benchmark the new TVFEMD-GPR model, the long short-term memory (LSTM), boosted regression tree (BRT), and cascaded forward neural network (CFNN) were also developed to assess their accuracy in drought forecasting. Moreover, the TVFEMD was integrated to create TVFEMD-LSTM, TVFEMD-BRT, and TVFEMD-CFNN models to forecast multi-scaler SPI where the TVFEMD-GPR surpassed all comparable models in both stations. The outcomes proved that the TVFEMD-GPR outperformed comparable models by acquiring ENS = 0.5054, IA = 0.8082, U95% = 1.8943 (SPI1), ENS = 0.6564, IA = 0.8893, U95% = 1.5745(SPI3), ENS = 0.8237, IA = 0.9502, U95% = 1.1123 (SPI6), and ENS = 0.9285, IA = 0.9813, U95% = 0.7228 (SPI12) for Mackay Station. For Station 2 (Springfield), the TVFEMD-GPR obtained these metrics as ENS = 0.5192, IA = 0.8182, U95% = 1.9100 (SPI1), ENS = 0.6716, IA = 0.8953, U95% = 1.5163 (SPI3), ENS = 0.8289, IA = 0.9534, U95% = 1.1296 (SPI6), and ENS = 0.9311, IA = 0.9829, and U95% = 0.7695 (SPI12). The research exhibits the practicality of the TVFEMD-GPR model to anticipate drought events, minimize their impacts, and implement timely mitigation strategies. Moreover, the TVFEMD-GPR can assist in early warning systems, better water management, and reducing economic losses. Full article

(This article belongs to the Special Issue Applications of Artificial Intelligence (AI) in Water Resources Systems)

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18 pages, 3041 KB

Open AccessArticle

Spatio-Temporal Dynamics of Wetland Ecosystem and Its Driving Factors in the Qinghai–Tibet Plateau

by Haoyuan Zheng and Yinghui Guan

Water 2025, 17(18), 2746; https://doi.org/10.3390/w17182746 - 17 Sep 2025

Abstract

Globally, wetlands have suffered severe degradation due to natural environmental changes and human activities. The wetlands on the Qinghai–Tibet Plateau (QTP) play a unique and critical ecological role, making it essential to understand their spatiotemporal dynamics and driving forces for effective conservation. Based [...] Read more.

Globally, wetlands have suffered severe degradation due to natural environmental changes and human activities. The wetlands on the Qinghai–Tibet Plateau (QTP) play a unique and critical ecological role, making it essential to understand their spatiotemporal dynamics and driving forces for effective conservation. Based on multi-source remote sensing data and Partial Least Squares Structural Equation Modeling (PLS-SEM), this study comprehensively quantified the spatiotemporal changes in wetlands and their key driving factors on the QTP from 1990 to 2020. The results show a net increase in total wetland area (including both natural and artificial wetlands) of approximately 538.72 km² per year over the 30-year period. Spatially, wetland expansion was most pronounced in the central–western and northern parts of the plateau, primarily driven by the conversion of grasslands, barren lands, and snow/ice cover, while localized degradation persisted in eastern regions. The PLS-SEM demonstrated an excellent fit (R² = 0.962) and identified human activities—such as ecological restoration policies and infrastructure development—as the dominant direct driver of wetland expansion (path coefficient = 0.918). Climate change, improved vegetation cover, and cryospheric loss also contributed positively to wetland gains (path coefficients = 0.056, 0.044, and 0.138, respectively). This study provides a transferable framework for understanding complex wetland dynamics and their drivers in alpine regions under global environmental change, which is crucial for designing more effective wetland conservation strategies. Full article

(This article belongs to the Special Issue Impact of Climate Change on Water and Soil Erosion)

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22 pages, 4329 KB

Open AccessArticle

Fractal-Based Approach to Simultaneous Layout Routing and Pipe Sizing of Water Supply Networks

by Paweł Suchorab, Dariusz Kowalski and Małgorzata Iwanek

Water 2025, 17(18), 2745; https://doi.org/10.3390/w17182745 - 17 Sep 2025

Abstract

The process of designing water distribution networks is divided into two main stages: network layout routing and pipe sizing. However, routing and sizing are not separate tasks—the shape of the network affects the diameters of the pipes, and vice versa. This paper presents [...] Read more.

The process of designing water distribution networks is divided into two main stages: network layout routing and pipe sizing. However, routing and sizing are not separate tasks—the shape of the network affects the diameters of the pipes, and vice versa. This paper presents an innovative fractal-based method, which enables the simultaneous layout routing and pipe sizing of water supply networks. The developed pipe routes and diameters selected according to the method are mathematically justified; the selection considers the total length of the pipes, the number of rotation angles of the base section, the cost of the water supply system construction and the priority of water supply to individual customers. The novelty of the method lies in the possibility of carrying out the processes of routing and sizing of the network in a recursive manner by the adoption of the principles of fractal geometry and Murray’s law. The method was tested under the conditions of a synthetic settlement. The obtained results enable us to conclude that the method is universal and suitable for shaping water supply networks, while determining the pipes’ diameters, both under the conditions of a single- and multi-sided water supply source. Full article

(This article belongs to the Special Issue Advances in Management and Optimization of Urban Water Networks)

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15 pages, 1501 KB

Open AccessArticle

Resilient Strategies for Disaster Prevention and Ecological Restoration of River and Lake Benggang and Bank Erosion

by Huihuang Qin and Yong Ye

Water 2025, 17(18), 2744; https://doi.org/10.3390/w17182744 - 17 Sep 2025

Abstract

The research on river and lake resilience management, ecological restoration, and disaster reduction technologies aims to comprehensively improve the health, stability, and sustainability of aquatic ecosystems. It seeks to reduce the natural disaster risk, promote the sustainable use of water resources, protect biodiversity, [...] Read more.

The research on river and lake resilience management, ecological restoration, and disaster reduction technologies aims to comprehensively improve the health, stability, and sustainability of aquatic ecosystems. It seeks to reduce the natural disaster risk, promote the sustainable use of water resources, protect biodiversity, strengthen water ecological environment supervision, and advance the widespread practice of the green development concept. This study integrates remote sensing, geographic information system (GIS), and biological slope protection technologies, supported by investigation and geomorphological surveys, to achieve real-time monitoring and data analysis of river and lake ecosystems. Additionally, the application of innovative ecological restoration materials and technologies significantly improves restoration outcomes and operational efficiency. The construction of multi-level wetlands, combined with active community participation, further enhances ecological resilience and stability. Experimental results show that the river and lake resilience management structure increases the strength of slope protection by more than 1.5 times and improves the overall stability by more than 25%. These findings underscore the critical role of integrated ecological and engineering approaches in achieving sustainable development of river and lake ecosystems while effectively reducing the risks of natural disasters. Full article

(This article belongs to the Special Issue Protection and Restoration of Lake and Water Reservoir)

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20 pages, 4581 KB

Open AccessArticle

The Fracture Propagation Behavior of Coal Masses Under Various Waveforms, Amplitudes, and Frequencies of Water Hammer Pulsating Pressure: Numerical Simulation and Experimental Validation

by Jun Nian, Jingchi Zhu, Xiaobo Lv and Jinqi Fu

Water 2025, 17(18), 2743; https://doi.org/10.3390/w17182743 - 17 Sep 2025

Abstract

Deep coal seams have low permeability and poor wettability, making gas extraction difficult. This study presents a zero-energy consumption pulsating water hammer fracturing technique that uses the gravitational potential energy of high-elevation water and the pulsating pressure waves from the water hammer effect [...] Read more.

Deep coal seams have low permeability and poor wettability, making gas extraction difficult. This study presents a zero-energy consumption pulsating water hammer fracturing technique that uses the gravitational potential energy of high-elevation water and the pulsating pressure waves from the water hammer effect to induce fatigue damage in coal, creating an interconnected network of cracks. The research included experiments on water hammer pressure waves, multi-physics field coupling simulations at different flow rates, and discrete element simulations to analyze the fracture behavior of underwater hammer pressure. Results showed that initial flow velocity impacts the water hammer pressure’s intensity, range, and duration. Pressure shock waves propagate as expansion and compression waves, with peaks rising from 4.99 to 19.91 MPa within a 2–12 m/s flow rate range. Water hammer pressure reduced fracture initiation pressure by 23% compared to static pressure loading and increased fracture numbers by 13.4%. With pressure amplitudes between 2–18 MPa, fractures tripled, and the damaged area grew from 2.2 to 11%. A variable frequency combination loading strategy, starting with low frequency and then high frequency, was more effective for fracture propagation. This study offers a theoretical foundation for applying this technology to enhance coal seam permeability and gas pumping efficiency. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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19 pages, 15681 KB

Open AccessArticle

Optimization of Combined Scour Protection for Bridge Piers Using Computational Fluid Dynamics

by Xiangdong Wang, Wentao Li, Zhiwen Peng, Qianmi Yu, Yilin Yang and Jinzhao Li

Water 2025, 17(18), 2742; https://doi.org/10.3390/w17182742 - 16 Sep 2025

Abstract

This study presents a high-fidelity CFD-based optimization of a combined sacrificial-pile and collar (SPC) system designed to suppress local scour at circular bridge piers. Following rigorous validation against benchmark flume experiments (scour depth error < 3%), a systematic parametric study was conducted to [...] Read more.

This study presents a high-fidelity CFD-based optimization of a combined sacrificial-pile and collar (SPC) system designed to suppress local scour at circular bridge piers. Following rigorous validation against benchmark flume experiments (scour depth error < 3%), a systematic parametric study was conducted to quantify the influence of pile-to-pier spacing (d_p/D = 4–6) and collar elevation (h_c/D = 0–0.3). The optimal layout is found to be a sacrificial pile at d_p/D = 5 and a collar at h_c/D, which yields a 51.2% scour reduction relative to the unprotected case. Flow field analysis reveals that the pile wake deflects the lower approach flow, while the collar vertically displaces the horseshoe vortex; together, these mechanisms redistribute bed shear stress and prevent secondary undermining. Consequently, the upstream conical pit is virtually eliminated, lateral scour is broadened but markedly shallower, and the downstream dune tail bifurcates into two symmetrical ridges. To the best of the authors’ knowledge, this study presents the first high-fidelity CFD-based optimization of a combined sacrificial-pile and collar (SPC) system with a fully coupled hydrodynamic-morphodynamic model. The optimized layout yields a 51.2% scour reduction relative to the unprotected case and, more importantly, demonstrates a positive non-linear synergy that exceeds the linear sum of individual device efficiencies by 7.5%. The findings offer practical design guidance for enhancing bridge foundation resilience against scour-induced hydraulic failure. Full article

(This article belongs to the Special Issue Advances in Bridge Scour Mechanics, Monitoring, Prediction, and Mitigation Across Hydraulic, Coastal, and Ocean Engineering)

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17 pages, 6397 KB

Open AccessArticle

Quantitative Analysis of Hydraulic Fracture Geometry and Its Relationship with Key Water Hammer Pressure Features

by Yanchao Li, Hu Sun, Wei Liu, Longqing Zou, Liang Yang, Kai Wu, Lijun Liu and Shuangshuang Sun

Water 2025, 17(18), 2741; https://doi.org/10.3390/w17182741 - 16 Sep 2025

Abstract

Hydraulic fracturing technology is crucial for promoting oil and gas resource development. In recent years, water hammer fracture diagnostic techniques, derived from the water hammer effect in hydraulic fracturing, have garnered significant attention due to their low cost and ease of operation. The [...] Read more.

Hydraulic fracturing technology is crucial for promoting oil and gas resource development. In recent years, water hammer fracture diagnostic techniques, derived from the water hammer effect in hydraulic fracturing, have garnered significant attention due to their low cost and ease of operation. The characteristic parameters of water hammer pressure are closely related to fracture geometry parameters. Monitoring the characteristics of water hammer pressure at the wellhead allows for rapid assessment of fracturing effectiveness. This study comprehensively considers wellbore friction, perforation friction, and the fluid loss effect within hydraulic fractures, establishing a mathematical model for the evolution of water hammer pressure during multi-cluster staged fracturing in horizontal wells. Based on field-monitored water hammer data from multiple stages, this study employed water hammer fracture diagnostics to inversely determine the geometric parameters of fractures in different fracturing stages. Characteristic parameters of the water hammer pressure, including the initial amplitude, number of oscillations, oscillation duration, and attenuation rate, were calculated for different well sections. Furthermore, the correlations between these water hammer characteristics and the fracture geometric parameters were analyzed. The correlation analysis between characteristic parameters of water hammer pressure and geometric parameters of hydraulic fractures indicates that under conditions of longer fracture half-length and smaller fracture height, the generated water hammer pressure exhibits a higher initial amplitude, fewer oscillations, a shorter oscillation duration, and a larger attenuation rate. The research findings can facilitate rapid estimation of fracture geometry using water hammer pressure, thereby optimizing fracturing design and enhancing fracturing effectiveness. Full article

(This article belongs to the Special Issue Groundwater Environmental Impacts and Control Strategies of Coal Mining and Energy Development/Storage Activities)

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18 pages, 8138 KB

Open AccessArticle

Study of the Correlation Between Water Resource Changes and Drought Indices in the Yinchuan Plain Based on Multi-Source Remote Sensing and Deep Learning

by Hong Guan, Zhiguo Jiang, Jing Lu and Yukuai Wan

Water 2025, 17(18), 2740; https://doi.org/10.3390/w17182740 - 16 Sep 2025

Abstract

This study examines the intricate relationship between water resource dynamics and drought indices in the Yinchuan Plain, China, by integrating multi-source remote sensing data with advanced deep learning techniques. Using data from 2002 to 2022, we applied Long Short-Term Memory (LSTM) networks to [...] Read more.

This study examines the intricate relationship between water resource dynamics and drought indices in the Yinchuan Plain, China, by integrating multi-source remote sensing data with advanced deep learning techniques. Using data from 2002 to 2022, we applied Long Short-Term Memory (LSTM) networks to model the spatiotemporal dynamics of water resources and their relationships with the Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), and Palmer Drought Severity Index (PDSI). Our findings reveal a strong correlation between total water resources and the SPEI (r = 0.81, p < 0.001), underscoring the pivotal role of evapotranspiration in this region’s water balance. The LSTM model outperformed traditional statistical methods, achieving a Root Mean Square Error of 0.142 for water resource predictions and 0.118 for drought index forecasts. Spatial analysis indicated stronger correlations in the northern Yinchuan Plain, likely influenced by its proximity to the Yellow River and regional water management practices. Wavelet coherence analysis identified significant coherence at the 6–12-month scale, highlighting the importance of seasonal to inter-annual strategies for water resource management. These results provide a robust foundation for developing effective water management policies and drought mitigation strategies in arid and semi-arid regions. The methodologies presented are broadly applicable to similar water-scarce regions, contributing to global efforts in sustainable water resource management under changing climatic conditions. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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18 pages, 3997 KB

Open AccessArticle

A Novel Multimodal Large Language Model-Based Approach for Urban Flood Detection Using Open-Access Closed Circuit Television in Bandung, Indonesia

by Tsun-Hua Yang, Obaja Triputera Wijaya, Sandy Ardianto and Albert Budi Christian

Water 2025, 17(18), 2739; https://doi.org/10.3390/w17182739 - 16 Sep 2025

Abstract

Monitoring urban pluvial floods remains a challenge, particularly in dense city environments where drainage overflows are localized, and sensor-based systems are often impractical. Physical sensors can be costly, prone to theft, and difficult to maintain in areas with high human activity. To address [...] Read more.

Monitoring urban pluvial floods remains a challenge, particularly in dense city environments where drainage overflows are localized, and sensor-based systems are often impractical. Physical sensors can be costly, prone to theft, and difficult to maintain in areas with high human activity. To address this, we developed an innovative flood detection framework that utilizes publicly accessible CCTV imagery and large language models (LLMs) to classify flooding conditions directly from images using natural language prompts. The system was tested in Bandung, Indonesia, across 340 CCTV locations over a one-year period. Four multimodal LLMs, ChatGPT-4.1, Gemini 2.5 Pro, Mistral Pixtral, and DeepSeek-VL Janus, were evaluated based on classification accuracy and operational cost. ChatGPT-4.1 achieved the highest overall accuracy at 85%, with higher performance during the daytime (89%) and lower accuracy at night (78%). A cost analysis showed that deploying GPT-4.1 every 15 min across all locations would require approximately USD 59,568 per year. However, using compact models like GPT-4 nano could reduce costs by up to seven times, with minimal loss of accuracy. These results highlight the trade-off between performance and affordability, especially in developing regions. This approach offers a scalable, passive flood monitoring solution that can be integrated into early warning systems. Future improvements may include multi-frame image analysis, automated confidence filtering, and multi-level flood classification for enhanced situational awareness. Full article

(This article belongs to the Special Issue Machine Learning Models for Hydrological Inference: A Case Study for Flood Events)

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19 pages, 8064 KB

Open AccessArticle

Spatiotemporal Monitoring of the Effects of Climate Change on the Water Surface Area of Sidi Salem Dam, Northern Tunisia

by Yosra Ayadi, Malika Abbes, Matteo Gentilucci and Younes Hamed

Water 2025, 17(18), 2738; https://doi.org/10.3390/w17182738 - 16 Sep 2025

Abstract

This research presents a comprehensive spatiotemporal assessment of the effects of climate change and anthropogenic pressures on the water surface area and quality of the Sidi Salem Dam, the largest reservoir in Northern Tunisia. Located within a sub-humid to Mediterranean humid bioclimatic zone, [...] Read more.

This research presents a comprehensive spatiotemporal assessment of the effects of climate change and anthropogenic pressures on the water surface area and quality of the Sidi Salem Dam, the largest reservoir in Northern Tunisia. Located within a sub-humid to Mediterranean humid bioclimatic zone, the dam plays a vital role in regional water supply, irrigation, and flood control. Utilizing a 40-year dataset (1985–2025), this study integrates multi-temporal satellite imagery and geospatial analysis using Geographic Information System (GIS) and remote sensing (RS) techniques. The temporal variability of the dam’s surface water extent was monitored through indices such as the Normalized Difference Water Index (NDWI). The analysis was further supported by climate data, including records of precipitation, temperature, and evapotranspiration, to assess correlations with observed hydrological changes. The findings revealed a significant reduction in the dam’s surface area, from approximately 37.8 km² in 1985 to 19.8 km² in 2025, indicating a net loss of 18 km² (47.6%). The Mann–Kendall trend test confirmed a significant long-term increase in annual precipitation, while annual temperature showed no significant trend. Nevertheless, recent observations indicate a decline in precipitation during the most recent period. Furthermore, Pearson correlation analysis revealed a significant negative relationship between precipitation and temperature, suggesting that wet years are generally associated with cooler conditions, whereas dry years coincide with warmer conditions. This hydroclimatic interplay underscores the complex dynamics driving reservoir fluctuations. Simultaneously, land use changes in the catchment area, particularly the expansion of agriculture, urban development, and deforestation have led to increased surface runoff and soil erosion, intensifying sediment deposition in the reservoir. This has progressively reduced the dam’s storage capacity, further diminishing its water storage efficiency. This study also investigates the degradation of water quality associated with declining water levels and climatic stress. Indicators such as turbidity and salinity were evaluated, showing clear signs of deterioration resulting from both natural and human-induced processes. Increased salinity and pollutant concentrations are primarily linked to reduced dilution capacity, intensified evaporation, and agrochemical runoff containing fertilizers and other contaminants. Full article

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

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