Water

25 pages, 3511 KB

Open AccessArticle

Impact of Injected Water Chemistry on Mineral Precipitation and Dissolution in Medium–Deep Geothermal Systems: A Case Study of the Wumishan Formation Dolomite Reservoir

by Zheng Liu, Bo Feng, Kiryukhin Alexey, Jian Shen, Siqing He and Yilong Yuan

Water 2025, 17(21), 3099; https://doi.org/10.3390/w17213099 (registering DOI) - 29 Oct 2025

Abstract

The geochemical characteristics of reinjection fluids play a crucial role in controlling water–rock interactions and the long-term stability of geothermal reservoirs. This study aims to evaluate how different fluid chemistries affect mineral dissolution–precipitation behavior and ion migration during geothermal reinjection. Five types of [...] Read more.

The geochemical characteristics of reinjection fluids play a crucial role in controlling water–rock interactions and the long-term stability of geothermal reservoirs. This study aims to evaluate how different fluid chemistries affect mineral dissolution–precipitation behavior and ion migration during geothermal reinjection. Five types of reinjection water—including geothermal source water (i.e., formation water from the reservoir), primary and secondary treated waters, and their mixtures—were reacted with carbonate rocks from the Wumishan Formation of the Xiong’an New Area, North China Basin, under reservoir-like conditions (70 °C, 17 MPa). A combination of batch experiments, inverse modeling using PHREEQC, and one-dimensional reactive transport simulations was employed. Results show that fluid pH, ionic strength, and saturation state significantly influence reaction pathways. Alkaline-treated waters enhanced silicate dissolution, increasing Na⁺, K⁺, and Si concentrations, while source water and its mixtures promoted carbonate precipitation, increasing the risk of clogging. Simulations revealed that the early injection stage is the most reactive, with rapid ion front advancement and strong mineral transformations. Reaction-controlled ions such as Ca²⁺ and SO₄²⁻ formed enrichment zones, while conservative ions like Na⁺ and Cl⁻ propagated more uniformly. Moderate alkaline regulation was found to mitigate carbonate scaling and improve silicate reactivity, thereby reducing permeability loss. This integrated approach provides mechanistic understanding and practical guidance for reinjection fluid design in medium-to-deep geothermal systems. Full article

(This article belongs to the Section Hydrogeology)

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25 pages, 1464 KB

Open AccessArticle

Analytical Solution of the Full-Space Effect of Transient Electromagnetic Response from Anomalous Bodies in Tunnels

by Wangping Qian, Xiaoxin Ma, Yuanbin Zuo, Bo Wang, Yan Li and Zhanjun Du

Water 2025, 17(21), 3098; https://doi.org/10.3390/w17213098 (registering DOI) - 29 Oct 2025

Abstract

The transient electromagnetic method (TEM) is one of the most common and effective techniques for detecting anomalies in tunnel engineering. Traditional TEM interpretations often assumed a half-space model, which can be problematic in enclosed environments such as tunnels. This limitation often results in [...] Read more.

The transient electromagnetic method (TEM) is one of the most common and effective techniques for detecting anomalies in tunnel engineering. Traditional TEM interpretations often assumed a half-space model, which can be problematic in enclosed environments such as tunnels. This limitation often results in poor inversion accuracy, especially when full-space effects are pronounced. Utilizing thin-layer theory, this study derived analytical expressions for TEM responses under both full-space and half-space conditions and defined a ratio coefficient relating full-space and half-space responses in the presence of anomalous bodies. Furthermore, a sensitivity analysis of this ratio coefficient was conducted under varying conditions of surrounding rock and anomalous bodies, exploring the laws governing the full-space effect for anomalous bodies in tunnels. The research results indicate that when changes in surrounding rock or anomalous body conditions enhance the TEM response—such as when the anomalous body is closer to the receiver coil, thicker, or exhibits a larger conductivity contrast with the surrounding rock—the ratio coefficient between full-space and half-space responses decreases, potentially approaching 1.0. Conversely, when these changes weaken the anomalous body response, the ratio coefficient increases, approaching approximately 2.5, as observed under homogeneous medium conditions. Moreover, the off-time exerts a significant influence on the ratio coefficient. The earlier off-times yield larger coefficients, whereas the coefficient gradually approaches 1.0 with increasing time. Finally, this study elucidates the dynamic characteristics of the full-space effect and establishes a functional relationship describing the primary factors influencing the ratio coefficient. The findings provide a theoretical foundation for improving TEM detection of anomalous bodies in tunnels. Full article

13 pages, 420 KB

Open AccessArticle

Social Capital and Farmers’ Participation in Public Irrigation Infrastructure Investment—Evidence from Rural Xinjiang, China

by Changjiang Zhou, Abudureheman Abudikeranmu, Fangping Rao and Xiaoping Shi

Water 2025, 17(21), 3097; https://doi.org/10.3390/w17213097 (registering DOI) - 29 Oct 2025

Abstract

Effective investments in rural irrigation infrastructure are critical for sustainable agricultural development and rural revitalization. This study investigates how social capital influences farmers’ investment in public infrastructure in terms of management and maintenance of irrigation facilities in rural Xinjiang, China. By using field [...] Read more.

Effective investments in rural irrigation infrastructure are critical for sustainable agricultural development and rural revitalization. This study investigates how social capital influences farmers’ investment in public infrastructure in terms of management and maintenance of irrigation facilities in rural Xinjiang, China. By using field survey data from 700 farmers in southern Xinjiang, we distinguished traditional social capital from newly emerged social capital (accumulated aid assigned to Xinjiang governors by upper authorities) and found that (1) both social capitals significantly facilitate farmers’ investment in managing and maintaining irrigation maintenance, particularly the latter; (2) the main influencing mechanism is twofold, directly promoting irrigation investments and indirectly stimulating participation in non-agricultural employment. These findings suggest that policy interventions should simultaneously strengthen rural social networks and improve non-agricultural employment services to foster collective action in investing in public irrigation system management and maintenance. Full article

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

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24 pages, 5172 KB

Open AccessArticle

Reviving Urban Landscapes: Harnessing Pervious Concrete Pavements with Recycled Materials for Sustainable Stormwater Management

by Thilini A. Gunathilake, Kushan D. Siriwardhana, Nandika Miguntanna, Nadeeka Miguntanna, Upaka Rathnayake and Nitin Muttil

Water 2025, 17(21), 3096; https://doi.org/10.3390/w17213096 (registering DOI) - 29 Oct 2025

Abstract

This study examines the effectiveness of pervious concrete pavements as a sustainable and cost-effective stormwater management technique, particularly by incorporating locally sourced recycled materials into their design. It evaluates the stormwater treatment potential of three pervious concrete pavement types incorporating recycled plastic, glass, [...] Read more.

This study examines the effectiveness of pervious concrete pavements as a sustainable and cost-effective stormwater management technique, particularly by incorporating locally sourced recycled materials into their design. It evaluates the stormwater treatment potential of three pervious concrete pavement types incorporating recycled plastic, glass, and crushed concrete aggregates, with six design variations produced using 25% and 50% replacements of coarse aggregates from these materials. The key properties of pervious concrete, namely compressive strength, porosity, unit weight, and infiltration, and key water quality indicators, namely pH, electrical conductivity (EC), total suspended solids (TSS), colour, turbidity, chemical oxygen demand (COD), nitrate (NO₃⁻), and orthophosphate (PO₄³⁻), were analysed. Results indicated an overall improvement in the quality of the stormwater runoff passed through all pervious concrete pavements irrespective of composition. Notable reductions in turbidity, TSS, colour, COD, PO₄³⁻, and NO₃⁻ underscored the effectiveness of pervious concrete containing waste materials in the treatment of stormwater runoff. Pervious concrete pavements with 25% recycled concrete exhibited optimal performance in reducing TSS, COD, and PO₄³⁻ levels, while the 50% recycled concrete variant excelled in diminishing turbidity. However, the study found that the use of recycled materials in pervious concrete pavements affects properties like compressive strength and infiltration rate differently. While incorporating 25% and 50% recycled concrete aggregates did not significantly reduce compressive strength, the effectiveness of stormwater treatment varied based on the mix design and type of recycled material used. Thus, this study highlights the potential of utilizing recycled waste materials in pervious concrete pavements for sustainable stormwater management. Full article

(This article belongs to the Special Issue Sustainable Urban Water Management: The Role of Nature-Based Solutions)

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5 pages, 156 KB

Open AccessEditorial

Advanced Research on Marine Geology and Sedimentology

by Zhuangcai Tian and Shaotong Zhang

Water 2025, 17(21), 3095; https://doi.org/10.3390/w17213095 (registering DOI) - 29 Oct 2025

Abstract

The ocean floor is a vast, uncharted territory, rich with geological and sedimentological secrets waiting to be uncovered [...] Full article

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

24 pages, 30023 KB

Open AccessArticle

Numerical and Experimental Analysis of Internal Flow Characteristics of Four-Way Opposing Diaphragm Pump

by Guangjie Peng, Han Chai, Chengqiang Liu, Kai Zhao, Jianfang Zhang and Hao Chang

Water 2025, 17(21), 3094; https://doi.org/10.3390/w17213094 (registering DOI) - 29 Oct 2025

Abstract

This study investigates the steady-state behavior of a four-way opposed diaphragm pump. Simulations and experimental results confirm that peak stress locations align with observed damage sites. During the return stroke, diaphragm flipping induces tension at the flow-fixed interface edges, creating stress concentrations that [...] Read more.

This study investigates the steady-state behavior of a four-way opposed diaphragm pump. Simulations and experimental results confirm that peak stress locations align with observed damage sites. During the return stroke, diaphragm flipping induces tension at the flow-fixed interface edges, creating stress concentrations that contribute to fatigue and failure. Particle image velocimetry (PIV) shows that, under constant flow, increased voltage enhances umbrella valve opening, accelerates movement, broadens flow distribution, and disrupts symmetry. At 90°, valve-edge velocity exhibits sharp, high-amplitude oscillations and a narrow, elongated return region. Vortices near the valve port interfere with fluid motion, causing pressure fluctuations and potential sealing issues or increased opening resistance. Higher flow rates intensify vortex strength and shift their position, generating diaphragm pressure differentials that alter flow direction and velocity, reducing stability and inducing secondary vortices. Compared to a modified diaphragm, the standard type shows more complex vortex structures, greater flow instability, and dynamic response degradation under identical pressure and varying flow. These fragmented vortices further disrupt flow, affecting pump performance. The findings provide design insights for diaphragm pump optimization. Full article

(This article belongs to the Special Issue Hydrodynamics Science Experiments and Simulations, 2nd Edition)

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15 pages, 3133 KB

Open AccessArticle

The Decadal Increase in Terrestrial Water Storage in a Region Experiencing Rapid Transitions from Dry to Wet Periods

by David F. Boutt, Gabriel Olland, Julianna C. Huba and Nicole Blin

Water 2025, 17(21), 3093; https://doi.org/10.3390/w17213093 (registering DOI) - 29 Oct 2025

Abstract

Understanding the impact of climate change and altered hydrologic cycles on regional water storage trends is crucial for predicting changes in recharge and streamflow and informing decisions regarding drought resilience and flood mitigation. While many regions have become drier under global climate change, [...] Read more.

Understanding the impact of climate change and altered hydrologic cycles on regional water storage trends is crucial for predicting changes in recharge and streamflow and informing decisions regarding drought resilience and flood mitigation. While many regions have become drier under global climate change, the northeast United States has experienced an increased precipitation intensity, driving groundwater rise. This study integrates terrestrial water storage data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites and soil moisture data from Soil Moisture Active Passive (SMAP), as well as long-term instrumental groundwater records from USGS groundwater monitoring wells, to understand the nature of storage trends. The results show that while aquifer-wide groundwater storage anomalies have stabilized in recent years, shallow groundwater and certain surface water bodies have accumulated about 0.6 cm of water annually, adding over 10 cm to the landscape, since 2005. These findings indicate that excess water from heavy rainfall is mainly stored in the shallow subsurface as perched aquifers and temporary wetlands rather than deep (5–30 m) aquifers. Understanding this change in storage is crucial for improving water resource management and adapting more effectively to a changing climate in the region. Full article

(This article belongs to the Special Issue Global Water Risks Across Shared River Corridors in Transboundary Basins)

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27 pages, 3865 KB

Open AccessArticle

Risk Assessment of Heavy Metals in Groundwater for a Managed Aquifer Recharge Project

by Ghulam Zakir-Hassan, Lee Baumgartner, Catherine Allan, Jehangir F. Punthakey and Hifza Rasheed

Water 2025, 17(21), 3092; https://doi.org/10.3390/w17213092 (registering DOI) - 29 Oct 2025

Abstract

Managed aquifer recharge (MAR) can address challenges pertaining to water quality and security, land subsidence, and aquifer degradation. This study has been conducted in the irrigated plains of Indus River Basin (IRB) of Pakistan, where groundwater is being used for drinking, agriculture, industries, [...] Read more.

Managed aquifer recharge (MAR) can address challenges pertaining to water quality and security, land subsidence, and aquifer degradation. This study has been conducted in the irrigated plains of Indus River Basin (IRB) of Pakistan, where groundwater is being used for drinking, agriculture, industries, and other commercial purposes and where the Punjab Government is implementing the MAR project. The study aims to assess the existing level of heavy metals and trace elements contamination in the groundwater and to set baseline data for the suitability of the site for the MAR project. Groundwater samples from 20 tubewells were collected from an area of 1522 km² to investigate the level of heavy metals concentration in groundwater and to assess its suitability for irrigation and drinking. Samples were analyzed for Aluminum (Al), Arsenic (As), Barium (Ba), Cadmium (Cd), Cobalt (Co), Copper (Cu), Chromium (Cr), Lead (Pb), Manganese (Mn), Molybdenum (Mo), Nickel (Ni), Selenium (Se), Strontium (Sr), and Zinc (Zn). To elucidate the contamination trend of these metals, the Heavy Metal Pollution Index (HPI), Heavy Metal Index (HI), geostatistical description, Pearson correlation analysis, and geospatial mapping were employed. Results showed that groundwater in the study area is not suitable for drinking and may pose serious health risks. It should be, however, generally suitable for irrigation. This concludes that the site is suitable for the implementation of a MAR project where the intended use of groundwater is for irrigation. It has been recommended that the groundwater may not be used for direct human consumption in the study area. It has been recommended, too, that targeted monitoring of identified hotspots and assessment of soil and crop uptake are conducted so that industrial or wastewater discharge into irrigation supplies may be prevented and controlled. For policy decisions, distinguishing irrigation suitability from potable-water safety is essential. Full article

(This article belongs to the Special Issue Groundwater Resources: Their Protection, Restoration and Optimal Development)

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20 pages, 5155 KB

Open AccessArticle

Model-Driven Sewage System Design and Intelligent Management of the Wuhan East Lake Deep Tunnel Drainage Project

by Deqing Jin, Tao Wang and Xianming Wu

Water 2025, 17(21), 3091; https://doi.org/10.3390/w17213091 - 29 Oct 2025

Abstract

Rapid urbanization in China has overwhelmed traditional drainage systems, resulting in frequent flooding and water pollution in densely populated urban areas. This study focuses on the East Lake core area of Wuhan, proposing a deep tunnel drainage system to improve sewage storage and [...] Read more.

Rapid urbanization in China has overwhelmed traditional drainage systems, resulting in frequent flooding and water pollution in densely populated urban areas. This study focuses on the East Lake core area of Wuhan, proposing a deep tunnel drainage system to improve sewage storage and conveyance capacity. A pilot-scale pipe model was employed to determine the critical non-silting velocity for full-pipe sewage flow. Based on projected dry-season inflows and intercepted combined sewer discharges, the design capacities for pumping stations and pretreatment facilities were defined. A three-dimensional gas–liquid two-phase numerical model was used to simulate inflow shaft hydraulics at Erlangmiao, Luobuzui, and Wudong pretreatment stations. Simulation results confirm that all shafts meet energy dissipation and ventilation requirements, with uniform flow and velocity distributions that could be obtained by a vortex-type shaft. The system not only mitigates regional environmental challenges but also shows significant social, environmental, and economic benefits. Overall project design, applied methodology, simulation study, and outcomes could provide a valuable reference to deep tunnel drainage design and research. Full article

(This article belongs to the Section Urban Water Management)

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17 pages, 6053 KB

Open AccessArticle

Groundwater Urban Heat Island (GUHI) and Climate Warming: Insights from Two Decades of Monitoring in Wrocław, Poland

by Monika Hajnrych, Jan Blachowski and Magdalena Worsa-Kozak

Water 2025, 17(21), 3090; https://doi.org/10.3390/w17213090 - 29 Oct 2025

Abstract

Climate change and intensive urbanisation contribute to an increase in groundwater temperatures, leading to the development of the subsurface urban heat island (SubUHI) and Groundwater Urban Heat Island (GUHI) phenomenon. This article presents the results of comparative studies conducted in Wrocław (Poland) in [...] Read more.

Climate change and intensive urbanisation contribute to an increase in groundwater temperatures, leading to the development of the subsurface urban heat island (SubUHI) and Groundwater Urban Heat Island (GUHI) phenomenon. This article presents the results of comparative studies conducted in Wrocław (Poland) in two measurement campaigns in 2004–2005 and 2022–2024. The study aimed to assess long-term thermal changes in groundwater in relation to air temperature using statistical and spatial analyses. The data were processed using descriptive methods, interpolation (ordinary kriging), map algebra, and correlation analysis (Pearson). The results indicate a clear warming of groundwater, especially in the winter season, where the average temperature increase ranged from 2 to 4 °C compared to the first measurement period. The most substantial changes were observed in shallow Quaternary aquifers, showing a strong correlation with air temperature (r ≈ 0.8). Spatial analyses revealed the major groundwater temperature (GWT) increases in the city centre and densely built-up districts, confirming the intensification of the GUHI effect. In addition, a decrease in the seasonal amplitude of GWT and a local lowering of the water table were observed. Full article

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

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17 pages, 15672 KB

Open AccessArticle

Optimizing Parameters of Marine Hydrodynamic Models Based on AFS Theory and PCA

by Yangxin Zhang, Jiangmei Zhang, Xinghua Feng, Haolin Liu, Guowei Yang, Tuantuan Liu, Yongzhuo Liu and Jiaze Li

Water 2025, 17(21), 3089; https://doi.org/10.3390/w17213089 - 28 Oct 2025

Abstract

The parameter optimization of marine hydrodynamic models currently relies predominantly on expert empirical knowledge, but the quantitative indicators and weighting mechanisms for rapid calibration remain unclear due to inherent model uncertainties and complexities. This study addresses these challenges through expert questionnaires that collect [...] Read more.

The parameter optimization of marine hydrodynamic models currently relies predominantly on expert empirical knowledge, but the quantitative indicators and weighting mechanisms for rapid calibration remain unclear due to inherent model uncertainties and complexities. This study addresses these challenges through expert questionnaires that collect fuzzy evaluations of calibration criteria, developing an integrated methodology combining the theory of axiomatic fuzzy set (AFS) with principal component analysis (PCA). Numerical case studies quantify calibration indicator weights and assess critical parameter impacts, revealing that bathymetry and roughness coefficients predominantly govern simulation accuracy. Elevated roughness conditions demonstrate two regimes: (1) at 1–2 × baseline roughness, strong positive correlations (with a coefficient of determination R² increased by up to 0.568 compared to baseline) confirm effective model-data matching for tidal levels/currents; (2) beyond 2 × baseline roughness, progressive correlation decay accompanies increasing coefficients, indicating amplified simulation–measurement discrepancies. Notably, under reduced roughness conditions, high accuracy persists during spring/mid-tide phases but significantly diminishes during neap tides, demonstrating enhanced roughness sensitivity in low-tidal energy regimes. Full article

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

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23 pages, 2921 KB

Open AccessArticle

From Land to Water: The Impact of Landscape on Water Quality Through Linear Models

by Gabriel Rosário, Carolina Acuña-Alonso, Xana Álvarez, Luís Filipe Fernandes, Daniela Terêncio, Vitor Pereira, Cátia Santos, Marisa Lopes, Fernando Pacheco, Guilherme Gorni, Simone Varandas and António Fernandes

Water 2025, 17(21), 3088; https://doi.org/10.3390/w17213088 - 28 Oct 2025

Abstract

This work explores the relationship between landscape metrics and surface water in the Galicia-North Portugal Euroregion, employing 6,220,767 linear regression models through Python scripts to predict surface water quality. The Iberian Biological Monitoring Working Party (IBMWP) index, based on benthic macroinvertebrate communities from [...] Read more.

This work explores the relationship between landscape metrics and surface water in the Galicia-North Portugal Euroregion, employing 6,220,767 linear regression models through Python scripts to predict surface water quality. The Iberian Biological Monitoring Working Party (IBMWP) index, based on benthic macroinvertebrate communities from 40 sites across Portugal (PT) and Galicia (GL), served as the biological indicator. The models were initially selected based on linear regression assumptions (17 tests), and validated against real-world data, evaluating statistical performance through indicators such as R-squared, mean absolute percentage error (MAPE), and percentage bias (PBIAS). Results indicated that GL had a higher macroinvertebrate abundance, whereas Portugal showed greater diversity and family richness. Statistical analysis revealed that landscape significantly influenced water quality, with land use composition and configuration driving differences in ecological conditions between regions. The best-performing models demonstrated a high R-squared value of 0.7, a MAPE of 27% for calibration (PT) and 10% for the validation (GL), indicating a strong predictive relationship. The models provide valuable insights into the complex interactions between landscape patterns and water quality, highlighting how variations in landscape structure can directly affect ecological integrity. These findings reinforce the need for strategic land management to preserve water quality and emphasizing the importance of transboundary governance across the Euroregion to foster sustainable development. Full article

(This article belongs to the Section Water Quality and Contamination)

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21 pages, 6943 KB

Open AccessArticle

Impacts of Land Use Change on Regional Water Conservation Carrying Capacity Under Urban Expansion: A Case Study of Gansu Province, China

by Kaiyuan He, Zhiying Shao, Mingming Zhu, Ziyang Qiang and Qiao Sun

Water 2025, 17(21), 3087; https://doi.org/10.3390/w17213087 - 28 Oct 2025

Abstract

Water conservation, as a critical ecosystem service, plays a vital role in maintaining regional water resources balance. Against the backdrop of rapid urbanization, the expansion of construction land has intensified the encroachment on ecological spaces, posing significant challenges to water resource carrying capacity. [...] Read more.

Water conservation, as a critical ecosystem service, plays a vital role in maintaining regional water resources balance. Against the backdrop of rapid urbanization, the expansion of construction land has intensified the encroachment on ecological spaces, posing significant challenges to water resource carrying capacity. From a supply–demand perspective, this study employs the InVEST model and integrates multi-source data including meteorological and socio-economic datasets to construct models of water conservation supply and demand. Furthermore, spatial analysis methods are applied to examine the evolution of water resource carrying capacity in Gansu Province—a key region within the Yellow River Basin—from 2000 to 2020. The results indicate the following: (1) through desertification control, unused land has been progressively restored to grassland, yet continuous urban expansion has substantially encroached upon surrounding plowland and grassland; (2) the spatial pattern of water conservation supply exhibits a “high in the south and west, low in the north and east” distribution, with the maximum value per pixel increasing from 7.89 × 10⁵ m³ to 8.15 × 10⁵ m³. Overall, water resource carrying capacity has generally declined, with intensified pressure in central cities such as Lanzhou, while some improvement is observed in forested areas of the south; and (3) cold spots in the western Qilian Mountains have expanded toward the Hexi Corridor, reflecting significant spatial changes and indicating ecological degradation. Urbanization has markedly exacerbated regional imbalances in water resource carrying capacity, providing a scientific basis for water–ecological risk management in arid regions. Full article

(This article belongs to the Special Issue Water Management and Uses: Comprehensive Analysis of Landscape, Heritage and Environment)

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28 pages, 18793 KB

Open AccessArticle

Long Term Rain Patterns of Major Watersheds in Saudi Arabia

by A A Alazba, Amr Mossad, Hatim M. E. Geli, Ahmed El-Shafei, Nasser Alrdyan, Mahmoud Ezzeldin and Farid Radwan

Water 2025, 17(21), 3086; https://doi.org/10.3390/w17213086 - 28 Oct 2025

Abstract

Understanding long-term rainfall variability is essential for addressing Saudi Arabia’s growing challenges of water scarcity, climate resilience, and sustainable resource management in its arid to hyper-arid environment. This study analyzes the spatiotemporal variations and long-term rainfall trends across the 13 administrative regions of [...] Read more.

Understanding long-term rainfall variability is essential for addressing Saudi Arabia’s growing challenges of water scarcity, climate resilience, and sustainable resource management in its arid to hyper-arid environment. This study analyzes the spatiotemporal variations and long-term rainfall trends across the 13 administrative regions of the Kingdom of Saudi Arabia (KSA) using four decades of observed data (1982–2021) from the National Center for Meteorology (NCM). The non-parametric Mann–Kendall (M–K) test and Sen’s slope estimator were applied to detect and quantify rainfall trends. Results reveal that 10 of the 13 regions show statistically significant negative trends, excluding the Eastern, Mecca, and Tabuk regions, with declines ranging from −4 to −16 mm/yr. The most pronounced decreases occurred in Hail, Al-Qassim, Riyadh, Medina, and Asir, while Mecca and Tabuk exhibited weak positive signals during the last decade, likely linked to Red Sea Trough dynamics. Seasonal analysis indicates the largest declines during winter and spring, crucial periods for groundwater recharge and agriculture, whereas summer rainfall remains localized in the southwestern highlands with a slight decreasing trend. Overall, rainfall variability in Saudi Arabia reflects both long-term drying and short-term oscillations. The findings provide a robust rainfall baseline to support water security, climate adaptation, and sustainable management strategies in one of the world’s driest regions. Full article

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

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18 pages, 2721 KB

Open AccessArticle

Bayesian Network-Based Earth-Rock Dam Breach Probability Analysis Integrating Machine Learning

by Zongkun Li, Qing Shi, Heqiang Sun, Yingjian Zhou, Fuheng Ma, Jianyou Wang and Pieter van Gelder

Water 2025, 17(21), 3085; https://doi.org/10.3390/w17213085 - 28 Oct 2025

Abstract

Earth-rock dams are critical components of hydraulic engineering, undertaking core functions such as flood control and disaster mitigation. However, the potential occurrence of dam breach poses a severe threat to regional socioeconomic stability and ecological security. To address the limitations of traditional Bayesian [...] Read more.

Earth-rock dams are critical components of hydraulic engineering, undertaking core functions such as flood control and disaster mitigation. However, the potential occurrence of dam breach poses a severe threat to regional socioeconomic stability and ecological security. To address the limitations of traditional Bayesian network (BN) in capturing the complex nonlinear coupling and dynamic mutual interactions among risk factors, they are integrated with machine learning techniques, based on a collected dataset of earth-rock dam breach case samples, the PC structure learning algorithm was employed to preliminarily uncover risk associations. The dataset was compiled from public databases, including the U.S. Army Corps of Engineers (USACE) and Dam Safety Management Center of the Ministry of Water Resources of China, as well as engineering reports from provincial water conservancy departments in China and Europe. Expert knowledge was integrated to optimize the network topology, thereby correcting causal relationships inconsistent with engineering mechanisms. The results indicate that the established hybrid model achieved AUC, accuracy, and F1-Score values of 0.887, 0.895, and 0.899, respectively, significantly outperforming the data-driven model G1. Forward inference identified the key drivers elevating breach risk. Conversely, backward inference revealed that overtopping was the direct failure mode with the highest probability of occurrence and the greatest contribution. The integration of data-driven approaches and domain knowledge provides theoretical and technical support for the probabilistic quantification of earth-rock dam breach and risk prevention and control decision-making. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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24 pages, 1058 KB

Open AccessArticle

SWOT-Based Evaluation of Nature-Based Solutions for Stormwater Resilience in Historic Urban Landscapes

by Yanjing Huang, Jiayu Zhao, Rana Muhammad Adnan and Mo Wang

Water 2025, 17(21), 3084; https://doi.org/10.3390/w17213084 - 28 Oct 2025

Abstract

Urban flooding increasingly threatens the resilience of historic urban landscapes (HULs), where conventional gray infrastructure often fails to balance flood protection with cultural preservation. This study systematically evaluates five stormwater management models—conventional drainage, direct surface infiltration, subterranean infiltration, surface infiltration with retention at [...] Read more.

Urban flooding increasingly threatens the resilience of historic urban landscapes (HULs), where conventional gray infrastructure often fails to balance flood protection with cultural preservation. This study systematically evaluates five stormwater management models—conventional drainage, direct surface infiltration, subterranean infiltration, surface infiltration with retention at source, and stormwater retention—within the context of HULs. Using a structured SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis, combined with Internal Factor Evaluation (IFE) and External Factor Evaluation (EFE) matrices, we identify key implementation factors, performance trade-offs, and context-specific constraints. Expert surveys (n = 20) were conducted to assess the relative importance and uncertainty of SWOT elements, further visualized through an impact–uncertainty grid. The results highlight that while conventional systems offer proven reliability and regulatory alignment, they lack adaptability to climate change and ecological functions. In contrast, infiltration- and retention-based models enhance resilience, water quality, and multifunctional urban benefits but face challenges of space limitations, cost, and integration with heritage preservation requirements. The analysis underscores the need for interdisciplinary, participatory, and policy-supported approaches to embed Nature-Based Solutions into HULs. The findings provide evidence-based guidance for urban planners and policymakers seeking to reconcile stormwater management with cultural heritage protection, offering strategic pathways for sustainable and climate-resilient heritage cities. Full article

(This article belongs to the Section Urban Water Management)

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31 pages, 3511 KB

Open AccessArticle

Development and Comparison of Methods for Identification of Baseflow-Dominant Periods in Streamflow Records

by Amin Aghababaei, Norman L. Jones, Gustavious P. Williams, Eniola Webster-Esho, Ryan van der Heijden, Xueyi Li, T. Prabhakar Clement and Donna M. Rizzo

Water 2025, 17(21), 3083; https://doi.org/10.3390/w17213083 - 28 Oct 2025

Abstract

Accurately identifying baseflow-dominant (BFD) periods in streamflow records is crucial for evaluating low-flow conditions, groundwater interactions, and other water resource management issues. While baseflow separation methods are widespread, the definition and identification of BFD flows are relatively new areas. Here, we define BFD [...] Read more.

Accurately identifying baseflow-dominant (BFD) periods in streamflow records is crucial for evaluating low-flow conditions, groundwater interactions, and other water resource management issues. While baseflow separation methods are widespread, the definition and identification of BFD flows are relatively new areas. Here, we define BFD periods as flow conditions that occur with minimal contribution from quickflow, including periods dominated by bank flow, groundwater interaction, or residual flow routing through the system. We develop a comprehensive, expert-labeled dataset of BFD periods from 182 USGS stream gages across diverse hydrological settings in the continental United States as ground truth. Using this dataset, we evaluate various automated BFD identification methods, including three new approaches, a machine learning classifier, a gradient-based method, and a statistical method, as well as two established techniques: the BN77 and Strict Baseflow methods. Our results demonstrate that the machine learning model (RF-BFD) outperforms all other approaches, achieving an F1 score of 0.92 and 92% accuracy. This study characterizes challenges in identifying BDF periods and establishes benchmarks for improving BFD identification in large-scale hydrological studies. The findings offer a pathway toward more robust and scalable BFD identification techniques, enhancing low-flow forecasting and groundwater-surface water interaction assessments. Full article

(This article belongs to the Special Issue Advances in Research on Hydrology and Water Resources)

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22 pages, 6935 KB

Open AccessArticle

Data Recovery Methods for Sensor Data in Water Distribution Systems Based on Spatiotemporal Redundancy

by Ang Xu, Lele Tao, Shuangshuang Cai, Zhaoxue Guo and Shipeng Chu

Water 2025, 17(21), 3082; https://doi.org/10.3390/w17213082 - 28 Oct 2025

Abstract

With the rapid development of smart water distribution systems, real-time monitoring data from large-scale sensor networks plays a critical role in system optimization and failure prediction. However, sensor data quality is often compromised by faults and missing values, which significantly undermine the reliability [...] Read more.

With the rapid development of smart water distribution systems, real-time monitoring data from large-scale sensor networks plays a critical role in system optimization and failure prediction. However, sensor data quality is often compromised by faults and missing values, which significantly undermine the reliability of decision-making. To address this issue, this study proposes a spatiotemporal redundancy-based data recovery method for sensor data. Specifically, polynomial fitting and hierarchical clustering are employed to analyze the spatiotemporal redundancy inherent in sensor data, based on which a weighted feature matrix is constructed. This matrix is then subjected to dimensionality reduction to enhance data representativeness. Five models—Multivariate Polynomial Regression, Holt-Winters, Long Short-Term Memory Sequence-to-Sequence, Multi-scale Isometric Convolution Network, and Transformer—were systematically compared in data recovery tasks. Experiments were conducted using real-world data from a water distribution system in China, involving 58 pressure sensors and 36 flow sensors. Results demonstrated that the developed method achieved high accuracy alongside efficient computation, particularly excelling in scenarios with abundant spatial redundancy. Full article

(This article belongs to the Section Urban Water Management)

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19 pages, 617 KB

Open AccessArticle

From Digitalization to Intelligentization: How Do Marine Ranches Evolve?

by Juying Wang, Huiyi Su and Zhigang Li

Water 2025, 17(21), 3081; https://doi.org/10.3390/w17213081 - 28 Oct 2025

Abstract

Under China’s diversified food supply strategy and the accelerated modernization of its fisheries sector, marine ranches have become vital food sources and production bases. Their digital–intelligent transformation now represents a key pathway to improve resource efficiency, ensure food security, and promote sustainable marine [...] Read more.

Under China’s diversified food supply strategy and the accelerated modernization of its fisheries sector, marine ranches have become vital food sources and production bases. Their digital–intelligent transformation now represents a key pathway to improve resource efficiency, ensure food security, and promote sustainable marine economic development. Adopting a qualitative research design, this study examines China’s marine ranches using the TOE framework and a systemic grounded theory approach to identify key elements and evolutionary logic of their digital–intelligent transformation from multi-source qualitative data. It constructs a three-stage evolutionary model comprising “Technology and Facility Capacity Building Phase–Digital Resource Integration and Application Deepening Phase–Multi-stakeholder Collaboration and Systemic Governance Phase,” revealing the dynamic coupling mechanism among technological progress, organizational change, and environmental adaptation. Results indicate that the digital–intelligent transformation of marine ranches represents a systemic transition from technology-driven to collaborative governance, characterized by platform-based collaboration, factor restructuring, and institutional linkage. Based on these findings, this study proposes tiered policy and practice recommendations emphasizing institutional guidance by governments, innovation investments by enterprises, and ecological support from third-party platforms. The research not only expands the application scope of the TOE framework but also provides an applicable theoretical framework and policy reference for digital governance and sustainable development in marine fisheries. Full article

(This article belongs to the Special Issue Application of Artificial Intelligence Monitoring and Big Data Analysis in Marine Resource Management)

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