Water

22 pages, 3532 KiB

Open AccessArticle

Optimization of a Chlorella vulgaris-Based Carbon Sequestration Technique Using an Alkaline Medium of Wood Biomass Ash Extract

by György Fekete, Szandra Klátyik, András Sebők, Anna Boglárka Dálnoki, Anita Takács, Miklós Gulyás, Imre Czinkota, András Székács, Csaba Gyuricza and László Aleksza

Water 2024, 16(24), 3696; https://doi.org/10.3390/w16243696 (registering DOI) - 21 Dec 2024

Abstract

Algae communities as primary producers are essential elements of aquatic ecosystems and contribute significantly to oxygen production, carbon dioxide fixation, and nutrient transport processes in water bodies. The use of algae-based carbon capture and storage technologies does not produce harmful by-products that require [...] Read more.

Algae communities as primary producers are essential elements of aquatic ecosystems and contribute significantly to oxygen production, carbon dioxide fixation, and nutrient transport processes in water bodies. The use of algae-based carbon capture and storage technologies does not produce harmful by-products that require disposal, and the resulting algal biomass can be valuable across various industrial sectors. In this study, model experiments were conducted to develop sequential absorption–microalgae hybrid CO₂-capture methods. To facilitate CO₂ capture from flue gases, wood biomass ash (WBA), an agricultural by-product, was utilized for its alkaline properties, while the flue gas scrubbing medium was regenerated by algae that restored alkalinity during their growth. In our experiments, one of our goals was to determine the optimal conditions for achieving maximum algal biomass growth in the shortest possible time. The suitability of WBA for flue gas cleaning was tested via simulation of CO₂ introduction. Moreover, a method was developed to determine the dissolved inorganic carbon content with the use of an OxiTop device monitoring the changes in pressure. The applied device was a closed, static, and pressure-based respirometer originally designed to determine the biological activity of microorganisms in both solid and liquid samples. In addition, the effects of CO₂-enriched WBA extract on algae cultivation were also analyzed, confirming that it imposed no growth inhibition and identifying the concentration (10% WBA) that optimally promoted algal growth. The optimal initial algal concentration and nutrient conditions for maximum growth were also determined. Full article

(This article belongs to the Special Issue Microalgae Control and Utilization: Challenges and Perspectives)

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22 pages, 1221 KiB

Open AccessArticle

Adsorptive Elimination of Cu(II) Ions from Aqueous Solution onto Chitosan Modified with Uracil

by Muneera Alrasheedi, Ard elshifa M. E. Mohammed, Nouf F. Al-harby, Ghada E. Khedr and Nadia A. Mohamed

Water 2024, 16(24), 3695; https://doi.org/10.3390/w16243695 (registering DOI) - 21 Dec 2024

Abstract

The remediation of industrial wastewater to eliminate heavy metal ions represents a pressing environmental requirement. A previously prepared adsorbent, based on chitosan modified with uracil (UCs), was investigated for the first time in this work to eliminate Cu(II) ions. The best conditions for [...] Read more.

The remediation of industrial wastewater to eliminate heavy metal ions represents a pressing environmental requirement. A previously prepared adsorbent, based on chitosan modified with uracil (UCs), was investigated for the first time in this work to eliminate Cu(II) ions. The best conditions for elimination were as follows: adsorbent dose = 0.01 g, Cu(II) ions solution concentration = 0.2 g L⁻¹, pH = 6, and temperature = 25 °C. The adsorption kinetics were favorable for the pseudo second order due to the correlation coefficient’s value being the highest (R² = 1.0). The experimental value of q_e (99.65 mg g⁻¹) was comparable to that of the theoretical one (100 mg g⁻¹). The removal efficiency reached 99.65%, and the adsorption isotherm coincided with the Freundlich model, denoting that the nature of its adsorption was multi-layered. Cu(II) ions removal mainly relies on the physisorption phenomenon. The desorption percentages reached 92.65, 75.29, 49.29, and 19.92% after four successive cycles. So, the insertion of nitrogen-rich uracil along the chitosan chains, as binding sites for Cu(II), is deemed to be an outstanding opportunity to produce an appropriate, efficacious adsorbent that is a good choice to apply in the metal removal domains. Full article

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

29 pages, 12937 KiB

Open AccessArticle

Redesigning the Fuse Plug, Emergency Spillway, and Flood Warning System: An Application of Flood Management

by Seyed Mohsen Sajjadi, Samireh Barihi, Javad Ahadiyan, Hossein Azizi Nadian, Mohammad Valipour, Farhad Bahmanpouri and Poria Khedri

Water 2024, 16(24), 3694; https://doi.org/10.3390/w16243694 (registering DOI) - 21 Dec 2024

Abstract

According to the World Health Organization (WHO), floods are one of the most important natural disasters in the world, resulting in the severe loss of human lives and intense destruction of infrastructure. The frequent floods in recent decades have caused most parts of [...] Read more.

According to the World Health Organization (WHO), floods are one of the most important natural disasters in the world, resulting in the severe loss of human lives and intense destruction of infrastructure. The frequent floods in recent decades have caused most parts of Iran to be affected by periodic and destructive floods. Consequently, the casualties and financial losses of floods have increased significantly. The present study aims to investigate redesigning the fuse plug, emergency overflow, and flood system at Ramshir Dam, Iran. In this regard, using a two-dimensional mathematical model, floods with a return period of 10 and 100 years with different scenarios have been investigated. Four scenarios were analyzed, including the current situation, flood channel dredging scenario, flood channel overhaul scenario, and flood channel overhaul scenario with reservoir dredging. The results show the following: (1) The flood channel in its current state cannot even discharge flows lower than the design, i.e., 1400 m³/s, and the flow overflows from the embankments on its sides. (2) Also, the reservoir dredging prevents the failure of the second fuse plug in the 100-year return period (flow rate 4370 m³/s). (3) Discharge more than 2400 m³/s cubic meters led to the activation of the first fuse plug. (4) The present research findings are of particular and essential importance in flood management. (5) The results of this research were based on the rehabilitation and simulation of the diversion dam facilities in the control and conveyance of flood and on three factors of spillway, flood channel, and flood plain, and the correct function of the fuse plug was reviewed. Full article

(This article belongs to the Special Issue Process-Form Relationship in Fan-Piedmont and River Areas Prone to Flooding)

21 pages, 8016 KiB

Open AccessArticle

Revealing Climate-Induced Patterns in Crop Yields and the Water-Energy-Food-Carbon Nexus: Insights from the Pearl River Basin

by Changxin Ye, Ze Yuan, Xiaohong Chen, Ruida Zhong and Lie Huang

Water 2024, 16(24), 3693; https://doi.org/10.3390/w16243693 (registering DOI) - 21 Dec 2024

Abstract

In the context of growing concerns over food security and climate change, research on sustainable agricultural development increasingly emphasizes the interconnections within agricultural systems. This study developed a regionally integrated optimization and prediction agricultural model to systematically analyze the impacts of climate change [...] Read more.

In the context of growing concerns over food security and climate change, research on sustainable agricultural development increasingly emphasizes the interconnections within agricultural systems. This study developed a regionally integrated optimization and prediction agricultural model to systematically analyze the impacts of climate change on agricultural systems and their feedback mechanisms from a water-energy-food-carbon (WEFC) nexus perspective. Applied to the Pearl River Basin, the model evaluates future trends in grain yield, water use, energy consumption, and carbon emissions under various climate scenarios throughout this century. The results indicate that rising temperatures significantly reduce crop yields, particularly in the western basin, increasing the environmental footprint per unit of grain produced. However, the CO₂ fertilization effect substantially offsets these negative impacts. Under the SSP585 scenario, CO₂ concentrations rising from 599.77 ppm to 1135.21 ppm by the century’s end led to a shift in crop yield trends from negative (Z = −7.03) to positive (Z = 11.01). This also reduces water, energy, and carbon footprints by 12.82%, 10.62%, and 10.59%, respectively. These findings highlight the critical importance of adaptive management strategies, including precision irrigation, optimized fertilizer use, and climate-resilient practices, to ensure sustainable agricultural production. Despite these insights, the model has limitations. Future research should incorporate uncertainty analysis, diverse adaptation pathways, and advanced technologies such as machine learning and remote sensing to improve predictive accuracy and applicability. This study offers valuable guidance for mitigating the adverse impacts of climate change on the WEFC nexus, supporting sustainable agricultural practices and science-based policy development. Full article

(This article belongs to the Special Issue Agricultural Water-Land-Plant System Engineering)

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17 pages, 2832 KiB

Open AccessArticle

Effects of Close-to-Nature Transformation of Plantations on Eco-Hydrological Function in Hainan Tropical Rainforest National Park

by Aohua Yang, Guijing Li, Wencheng Peng, Long Wan, Xiqiang Song, Yuguo Liu and Shouqian Nong

Water 2024, 16(24), 3692; https://doi.org/10.3390/w16243692 (registering DOI) - 21 Dec 2024

Abstract

Girdling is a crucial technique for promoting the close-to-nature transformation of plantation forests in Hainan Tropical Rainforest National Park (HNNP). It has shown effectiveness in aspects such as community structure and biodiversity restoration. However, its impacts on ecological functions like eco-hydrology still require [...] Read more.

Girdling is a crucial technique for promoting the close-to-nature transformation of plantation forests in Hainan Tropical Rainforest National Park (HNNP). It has shown effectiveness in aspects such as community structure and biodiversity restoration. However, its impacts on ecological functions like eco-hydrology still require further in-depth investigation. This study analyzes the impact of girdling on the eco-hydrological indices of three plantations—Acacia mangium, Pinus caribaea, and Cunninghamia lanceolata—through field investigations and laboratory tests. The data was evaluated using a game theory combination weighting-cloud model. The results show that the eco-hydrological indicators of leaf litter in A. mangium increased by 5.77% while those of P. caribaea and C. lanceolata decreased by 11.86% and 5.29%, respectively. Soil bulk density decreased slightly across all plantations while total porosity increased, with A. mangium showing the highest increase of 20.31%. Organic carbon content increased by 76.81% in A. mangium and 7.24% in C. lanceolata, whereas it decreased in P. caribaea. Saturated hydraulic conductivity increased by 33.32% in P. caribaea and 20.91% in A. mangium but decreased in C. lanceolata. Based on the cloud model, the eco-hydrological function of A. mangium improved from ‘medium’ to ‘good’, while that of P. caribaea and C. lanceolata declined towards the ‘poor’ level. In summary, during the process of close-to-nature transformation of tropical rainforests, girdling is an effective method to enhance the ecohydrological functions of broadleaf planted forests. However, for coniferous species, the ecohydrological functions of the planted forests weaken in the short term following the transformation. Full article

(This article belongs to the Section Ecohydrology)

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24 pages, 596 KiB

Open AccessArticle

Modeling of Water Resource Dynamics in SUR Systems Through Generalized Conformable Calculus in Arid Sites in Mexico

by Josué Neftalí Gutierrez-Corona, Luis Alberto Quezada-Téllez, Arturo Torres-Mendoza and Guillermo Fernandez-Anaya

Water 2024, 16(24), 3691; https://doi.org/10.3390/w16243691 (registering DOI) - 21 Dec 2024

Abstract

In this work, we present a comprehensive extension of the Surface–Underground–Recharge (SUR) water supply model through the incorporation of generalized conformable derivatives. This operator enables the capture of more exotic dynamics within the system, enhancing the modeling framework's ability to simulate complex hydrological [...] Read more.

In this work, we present a comprehensive extension of the Surface–Underground–Recharge (SUR) water supply model through the incorporation of generalized conformable derivatives. This operator enables the capture of more exotic dynamics within the system, enhancing the modeling framework's ability to simulate complex hydrological interactions. Additionally, we extend the results to the restricted phase spaces of the analyzed dynamical systems, facilitating a deeper qualitative analysis. To achieve this, we augment the dimension of the generalized conformable SUR system, rendering it an autonomous higher-order system. Furthermore, we introduce a novel conformable function, referred to as the generalized linear conformable combination function, which significantly broadens the scope of our modeling capabilities. Thus, this study contributes to the advancement of hydrological modeling, providing a robust tool for analyzing intricate water resource dynamics in specific regions. Full article

(This article belongs to the Topic Depth Averaged Models in Hydraulics: Modeling, Numerics and Applications)

17 pages, 7926 KiB

Open AccessArticle

Development of Multi-Temporal-Scales Precipitation-Type Separation Method in the Qinghai–Tibetan Plateau

by Juan Zhang, Weizhen Wang, Tao Che, Xianfeng Su and Wenjiang Su

Water 2024, 16(24), 3690; https://doi.org/10.3390/w16243690 (registering DOI) - 21 Dec 2024

Abstract

The accurate identification of precipitation types is very important for understanding the hydrological processes in cold regions. Existing identification methods have been established based on daily precipitation and meteorological data, which cannot match the high temporal resolution (such as hourly) simulations of hydrological [...] Read more.

The accurate identification of precipitation types is very important for understanding the hydrological processes in cold regions. Existing identification methods have been established based on daily precipitation and meteorological data, which cannot match the high temporal resolution (such as hourly) simulations of hydrological processes. Based on the minutely surface meteorological data in the QTP from 2012 to 2021, we established three sub-models of the dynamic threshold method with wet-bulb temperature (T_w) and three sub-models of the frequency threshold method with air temperature (T_a) for distinguishing among precipitation types. The results revealed that the mean accuracy (ACC) of the three precipitation types was 0.86, and that these models provided a refined and accurate precipitation identification performance for the Qinghai–Tibet Plateau (QTP). However, these models performed well in the identification of rain and snowfall but performed poorly in the identification of sleet. In addition, the smaller the time scale and regional scales, the better the identification rate. In particular, snowfall is overestimated when daily precipitation-type separation thresholds are input into hourly or minute hydrological models. Therefore, to improve simulation performance, it is important to develop multi-temporal scale precipitation-type partitioning models, take regional variations into account when setting temperature thresholds, and conduct analyses at the finest possible time resolutions to minimize scale-related uncertainties. Full article

(This article belongs to the Special Issue Precipitation under Climate Change: Observation, Analysis and Forecasting)

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8 pages, 366 KiB

Open AccessEditorial

Water Resource Management: Hydrological Modelling, Hydrological Cycles, and Hydrological Prediction

by Katarzyna Baran-Gurgul and Agnieszka Rutkowska

Water 2024, 16(24), 3689; https://doi.org/10.3390/w16243689 (registering DOI) - 21 Dec 2024

Abstract

This editorial provides a definitive review of ten articles published in the Special Issue of the journal Water, entitled “Water Resource Management: Hydrological Modelling, Hydrological Cycles, and Hydrological Prediction” [...] Full article

(This article belongs to the Special Issue Water Resource Management: Hydrological Modelling, Hydrological Cycles, and Hydrological Prediction)

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17 pages, 6349 KiB

Open AccessArticle

Study on a Geomorphic Indicator for Evaluating Sediment Transport Capacity in Mountainous Rivers

by Naoko Nagumo, Daisuke Harada and Shinji Egashira

Water 2024, 16(24), 3688; https://doi.org/10.3390/w16243688 (registering DOI) - 20 Dec 2024

Abstract

Flooding of water, sediment, and driftwood and its associated landform changes often occurs downstream of debris-flow deposition zones in small, mountainous river basins. This type of flooding occurs due to a sudden decrease in the sediment transport capacity of river channels, resulting in [...] Read more.

Flooding of water, sediment, and driftwood and its associated landform changes often occurs downstream of debris-flow deposition zones in small, mountainous river basins. This type of flooding occurs due to a sudden decrease in the sediment transport capacity of river channels, resulting in considerable damage. Despite the significant need for appropriate countermeasures to mitigate damage, it has been a challenge to plan and implement these across all river basins at risk of these hazards. However, if a simple but reliable tool is available to identify hazardous areas in advance, this would be extremely useful for prioritizing such areas and designing and implementing the required measures. To this end, this paper examines the geomorphic characteristics of recent flood events in Japan and proposes a method for identifying hazardous areas due to inundation by flood flows with sediment. We first explain the occurrence of sediment inundation by focusing on longitudinal changes in sediment transport capacity using the geomorphic indicator defined as the product of the drainage area

A

and bed slope

i

. In addition, we investigate the longitudinal profiles of the sediment transport capacity along the study channels using a one-dimensional governing equation for flood flows and, based on the results, discuss that finding that the computed longitudinal profiles of the sediment transport capacity are consistent with the longitudinal distribution of the

A i

. Our findings indicate that the

A i

is an effective indicator for identifying areas prone to inundation by flood flows with sediment. Full article

(This article belongs to the Special Issue Challenges to Interdisciplinary Application of Hydrodynamic Models)

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16 pages, 3809 KiB

Open AccessArticle

A Dam Displacement Prediction Method Based on a Model Combining Random Forest, a Convolutional Neural Network, and a Residual Attention Informer

by Chunhui Fang, Ying Jiao, Xue Wang, Taiqi Lu and Hao Gu

Water 2024, 16(24), 3687; https://doi.org/10.3390/w16243687 (registering DOI) - 20 Dec 2024

Abstract

To enhance the accuracy of dam displacement prediction, this paper proposes a hybrid model combining Random Forest (RF), a Convolutional Neural Network (CNN), and a Residual Attention Informer (RA-Informer). Firstly, RF is utilized to assess the importance of input features, selecting key factors [...] Read more.

To enhance the accuracy of dam displacement prediction, this paper proposes a hybrid model combining Random Forest (RF), a Convolutional Neural Network (CNN), and a Residual Attention Informer (RA-Informer). Firstly, RF is utilized to assess the importance of input features, selecting key factors that significantly influence dam displacement. Then, CNN is employed to perform deep feature extraction on the input data, mining effective information. Subsequently, the Informer model integrated with a residual attention mechanism establishes the mapping relationship between the extracted features and dam displacement, enhancing the focus on critical features. Finally, the Northern Goshawk Optimization (NGO) algorithm is adopted to optimize the model’s hyperparameters. Experimental results on actual engineering data demonstrate that the proposed model exhibits superior prediction accuracy and stability compared to other typical models, offering higher precision and reliability. Full article

(This article belongs to the Special Issue Hydraulic Engineering Applications of Artificial Intelligence, Deep Learning, and Digital Twin Technology)

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22 pages, 1070 KiB

Open AccessArticle

Targets for Urban Stormwater Management in Australia

by Dan O’Halloran, Jonathon McLean, Peter Morison, Alex Sims, Tony Weber, Kim Markwell, Ben Walker, Oliver Light and Barry Hart

Water 2024, 16(24), 3686; https://doi.org/10.3390/w16243686 (registering DOI) - 20 Dec 2024

Abstract

Increasing urbanisation is occurring in Australia’s major cities and in almost every country in the world. This creates a challenge for the urban water sector, which not only needs to provide traditional water services (i.e., wastewater, domestic water) for a rapidly growing population, [...] Read more.

Increasing urbanisation is occurring in Australia’s major cities and in almost every country in the world. This creates a challenge for the urban water sector, which not only needs to provide traditional water services (i.e., wastewater, domestic water) for a rapidly growing population, but also to service potential additional demands to contribute to enhanced amenity, and to do so in the context of climate change. This paper is focused on stormwater management controls for the develop of new greenfield urban sites in the three major east coast Australian cities—Melbourne, Sydney and Brisbane. While stormwater management in all three cities is focused on the protection of community values of the waterways, including environment (ecology), amenity and recreation, the scale or type of the waterways considered is considerably different—Melbourne has adopted a regional waterway strategy, while the Sydney and Brisbane approach is more localised. Pollution load reduction targets (TSS, TP, TN and litter) from new urban areas have been enforced in all three cities for many years, although there is concern that these targets primarily aimed at protecting the values of downstream bays (e.g., Port Phillip Bay, Sydney Harbour and Morton Bay) will not necessarily protect the values of the contributing waterways. However, targets to control stormwater volumes entering waterways are proving to be considerably more difficult to both develop and implement. These targets are typically expressed as volumes of stormwater to be harvested and/or infiltrated for every additional hectare of directly connected impervious (DCI) surface created as a result of urban development. The three cities have approached the setting of stormwater flow targets somewhat differently, as is apparent from the details provided in the paper. Additionally, we argue that there is a need for the development of new targets related to the reuse of stormwater and its integration with wastewater and domestic water management. Full article

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

16 pages, 2511 KiB

Open AccessArticle

Impacts of N₂O Oversaturated Sewage Effluents on the Spatial Distribution of Riverine N₂O: Insights from Sanya Estuaries, Hainan Province

by Dajun Qin, Jing Geng, Bingnan Ren and Bo Yang

Water 2024, 16(24), 3685; https://doi.org/10.3390/w16243685 (registering DOI) - 20 Dec 2024

Abstract

Rivers and estuaries are recognized as significant sources of atmospheric greenhouse gas nitrous oxide (N₂O), primarily through diffusive pathways. Anthropogenic nitrogen contributions to surface water bodies can alter the baseline emissions from natural sources; however, due to high spatial variability and [...] Read more.

Rivers and estuaries are recognized as significant sources of atmospheric greenhouse gas nitrous oxide (N₂O), primarily through diffusive pathways. Anthropogenic nitrogen contributions to surface water bodies can alter the baseline emissions from natural sources; however, due to high spatial variability and limited datasets, the specific sources and sinks contributing to N₂O remain poorly understood. This study investigates the sources and sinks of nitrous oxide (N₂O) in river systems located in Sanya, Hainan Province, China. In April 2023, we collected 48 samples of river water and seawater, measuring hydrochemical parameters in situ while analyzing N₂O concentrations in the laboratory. The results indicate that N₂O concentrations vary significantly across different river systems within Sanya. Specifically, N₂O concentrations ranged from 0.33 to 307.18 nmol/L for samples from the Sanya River, 2.28 to 3113.46 nmol/L for samples from Damaoshui River, 5.72 to 122.75 nmol/L for Tengqiao River waters, and between 11.08 and 18.07 nmol/L for Ningyuan River waters; coastal seawater exhibited concentrations ranging from 2.42 to 21.96 nmol/L. Notably, we observed that riverine N₂O levels near sewage discharge points were oversaturated—indicating a peak concentration—which subsequently declined towards levels more consistent with those found in natural river systems as one approaches the mouths of estuaries. Both Sanya River and Damaoshui River appear to be significant sources of N₂O; conversely, coastal seawater is not considered a substantial source. Our data suggest that wastewater discharges may play a critical role in influencing N₂O levels within river waters by directly introducing oversaturated effluents into these ecosystems. Full article

(This article belongs to the Special Issue The Environmental Fate and Transport of Organic Pollutants)

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19 pages, 7686 KiB

Open AccessArticle

Application of the Entropy Model to Estimate Flow Discharge and Bed Load Transport with Limited Field Measurements

by Farhad Bahmanpouri, Anshul Yadav, Christian Massari, Domenico De Santis, Ashutosh Sharma, Ankit Agarwal, Sumit Sen, Luigi Fraccarollo, Tommaso Moramarco and Silvia Barbetta

Water 2024, 16(24), 3684; https://doi.org/10.3390/w16243684 (registering DOI) - 20 Dec 2024

Abstract

Sediment transport can be observed within the flow of water in rivers, canals, and coastal regions, encompassing both suspended-load transport and bed-load transport. Bed-load transport specifically occurs near the riverbed, playing a crucial role in the formation of the riverbed itself. The current [...] Read more.

Sediment transport can be observed within the flow of water in rivers, canals, and coastal regions, encompassing both suspended-load transport and bed-load transport. Bed-load transport specifically occurs near the riverbed, playing a crucial role in the formation of the riverbed itself. The current study aimed to explore the process of sediment transport by employing the entropy concept as a theoretical approach. To this end, field data collected using a current meter in the Alaknanda River at Srinagar in India were utilized. A comparison was made between the calculated mean velocity and discharge values and the observed data obtained from the Central Water Commission (CWC), demonstrating a maximum error percentage of 9%. Subsequently, shear velocity was determined for various cross-sections under different flow scenarios. The Shields parameter was then derived from the shear-velocity distribution to evaluate the transport potential of the sediment particles. The model results showed varying bed-load transport rates that increased as the particle size decreased and the discharge rate increased. In conclusion, the study findings highlight the efficacy of utilizing the entropy theory for estimating flow discharge and sediment transport in developing countries. Full article

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

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27 pages, 6789 KiB

Open AccessArticle

Integrated Assessment of the Hydrogeochemical and Human Risks of Fluoride and Nitrate in Groundwater Using the RS-GIS Tool: Case Study of the Marginal Ganga Alluvial Plain, India

by Dev Sen Gupta, Ashwani Raju, Abhinav Patel, Surendra Kumar Chandniha, Vaishnavi Sahu, Ankit Kumar, Amit Kumar, Rupesh Kumar and Samyah Salem Refadah

Water 2024, 16(24), 3683; https://doi.org/10.3390/w16243683 - 20 Dec 2024

Abstract

Groundwater contamination with sub-lethal dissolved contaminants poses significant health risks globally, especially in rural India, where access to safe drinking water remains a critical challenge. This study explores the hydrogeochemical characterization and associated health risks of groundwater from shallow aquifers in the Marginal [...] Read more.

Groundwater contamination with sub-lethal dissolved contaminants poses significant health risks globally, especially in rural India, where access to safe drinking water remains a critical challenge. This study explores the hydrogeochemical characterization and associated health risks of groundwater from shallow aquifers in the Marginal Ganga Alluvial Plain (MGAP) of northern India. The groundwater chemistry is dominated by Ca-Mg-CO₃ and Ca-Mg-Cl types, where there is dominance of silicate weathering and the ion-exchange processes are responsible for this solute composition in the groundwater. All the ionic species are within the permissible limits of the World Health Organization, except fluoride (F⁻) and nitrate (NO₃⁻). Geochemical analysis using bivariate relationships and saturation plots attributes the occurrence of F⁻ to geogenic sources, primarily the chemical weathering of granite-granodiorite, while NO₃⁻ contaminants are linked to anthropogenic inputs, such as nitrogen-rich fertilizers, in the absence of a large-scale urban environment. Multivariate statistical analyses, including hierarchical cluster analysis and factor analysis, confirm the predominance of geogenic controls, with NO₃⁻-enriched samples derived from anthropogenic factors. The spatial distribution and probability predictions of F⁻ and NO₃⁻ were generated using a non-parametric co-kriging technique approach, aiding in the delineation of contamination hotspots. The integration of the USEPA human health risk assessment methodology with the urbanization index has revealed critical findings, identifying approximately 23% of the study area as being at high risk. This comprehensive approach, which synergizes geospatial analysis and statistical methods, proves to be highly effective in delineating priority zones for health intervention. The results highlight the pressing need for targeted mitigation measures and the implementation of sustainable groundwater management practices at regional, national, and global levels. Full article

(This article belongs to the Special Issue Groundwater Quality and Contamination at Regional Scales)

20 pages, 4251 KiB

Open AccessArticle

Exploring the Behavior of the High-Andean Wetlands in the Semi-Arid Zone of Chile: The Influence of Precipitation and Temperature Variability on Vegetation Cover and Water Quality

by Denisse Duhalde, Javiera Cortés, José-Luis Arumí, Jan Boll and Ricardo Oyarzún

Water 2024, 16(24), 3682; https://doi.org/10.3390/w16243682 (registering DOI) - 20 Dec 2024

Abstract

In recent decades, global ecosystems have increasingly faced impacts from heightened precipitation variability. Specifically, water availability is an essential factor in wetland dynamics and has ecological importance in the high-Andean wetlands in both mountains and downstream ecosystems, particularly in semi-arid regions. This study [...] Read more.

In recent decades, global ecosystems have increasingly faced impacts from heightened precipitation variability. Specifically, water availability is an essential factor in wetland dynamics and has ecological importance in the high-Andean wetlands in both mountains and downstream ecosystems, particularly in semi-arid regions. This study focused on a chain of twelve high-Andean wetlands within the “Estero Derecho” nature sanctuary at the headwaters of the Elqui River in north-central Chile. The analysis of the spatiotemporal dynamics of precipitation and vegetation cover used the Landsat 5 and 8 Satellite imagery-derived normalized difference vegetation index (NDVI) and normalized difference moisture index (NDMI) time series during the austral summer (December–March). We employed time series, boxplots, and least-squares regression analyses to explore vegetation cover behavior in relation to precipitation, water quality, and vegetation indices. Precipitation had a marked influence on vegetation behavior, particularly during the Chilean “megadrought” phenomenon. For both the NDVI and NDMI indices and precipitation, negative trends in the time series were observed, along with a highly significant correlation with a one-year lag between both indices and precipitation. The analysis of the individual wetlands showed different vegetation cover behaviors, which were attributable to the altitude, terrain slope, and additional water inputs from streams that have also given rise to alluvial fans that exert a shaping influence on the wetlands. In addition, significant correlations between both indices and water quality parameters (CE, Cl, Mg, Na, and Fe) were identified. The findings of this study can be incorporated into the Sanctuary’s management plan and concretely assist communities involved with wetland conservation. Full article

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28 pages, 8085 KiB

Open AccessArticle

Analyzing the Spatial Patterns and Impact Factors of Vegetation Net Primary Productivity and Precipitation Utilization Efficiency in Heilongjiang Province Under Climate Change

by Fangli Dong, Xinglong Mu, Fanxiang Meng, Ennan Zheng, Tianxiao Li, Hengfei Zhang and Shihao Jiang

Water 2024, 16(24), 3681; https://doi.org/10.3390/w16243681 - 20 Dec 2024

Abstract

Understanding the spatial patterns and driving mechanisms of net primary productivity (NPP) and precipitation utilization efficiency (PUE) is crucial for assessing ecosystem services. This study analyzed the variations in NPP and PUE in Heilongjiang Province from 2001 to 2020, using MOD17A3 NPP products [...] Read more.

Understanding the spatial patterns and driving mechanisms of net primary productivity (NPP) and precipitation utilization efficiency (PUE) is crucial for assessing ecosystem services. This study analyzed the variations in NPP and PUE in Heilongjiang Province from 2001 to 2020, using MOD17A3 NPP products and meteorological, topographic, and land use data. The distribution of the NPP and PUE of seven land use categories was determined in the study, namely, cropland, forest, grassland, water, barren, impervious and wetland. The multi-year spatial averages for NPP and PUE were 428.96 gC·m⁻²·a⁻¹ and 0.74 gC·m⁻²·mm⁻¹, respectively, with forests showing the highest values and barren lands the lowest. During the study period, 91.4% of the NPP increased at an average rate of 3.36 gC·m⁻²·a⁻¹, while PUE exhibited a polarized trend. Changes in land use, especially conversions involving cropland and forest, along with climatic factors such as rising precipitation and temperature, significantly influenced NPP and PUE dynamics. These findings provide a scientific basis for ecological restoration and the assessment of ecosystem function under changing climatic conditions. Full article

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12 pages, 2398 KiB

Open AccessArticle

Metagenomic Insights into the Microbial Community of Activated Sludge in Oxytetracycline Wastewater Treatment

by Rui Xiao, Da Kang, Haijing Zhao, Mingze Fan, Yang Peng and Jie Niu

Water 2024, 16(24), 3680; https://doi.org/10.3390/w16243680 - 20 Dec 2024

Abstract

The overuse of antibiotics in human society poses a global health challenge, necessitating effective treatment of antibiotic production wastewater. This study examines the microbial community within activated sludge in anaerobic digestion (AD) and biological nutrient removal (BNR) systems at a full-scale oxytetracycline production [...] Read more.

The overuse of antibiotics in human society poses a global health challenge, necessitating effective treatment of antibiotic production wastewater. This study examines the microbial community within activated sludge in anaerobic digestion (AD) and biological nutrient removal (BNR) systems at a full-scale oxytetracycline production wastewater treatment plant. The AD system effectively degraded polysaccharides but accumulated refractory humic-like substances, as determined by excitation–emission matrix fluorescence spectroscopy. Metagenomic analysis revealed distinct microbial communities between the AD and BNR systems, with Bacteroides (13.9%) and Proteiniphilum (33.5%) as the most abundant genus in the AD and BNR systems, respectively. Functional gene analysis showed a high presence of carbohydrate binding and glycoside hydrolases. The low abundance of nitrite oxidizer and the nxr gene might explain nitrite accumulation in the BNR system via partial nitrification. The antibiotic resistance genes (ARGs) affiliated with tetracycline were dominant in both the AD and BNR systems, with 45% of tetracycline and 20% of total ARGs being efficiently removed during the anaerobic treatment. The findings of this study can provide insights into microbial response to oxytetracycline production wastewater, informing the optimization of biological treatment processes and mitigating the environmental impacts of antibiotic production. Full article

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

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23 pages, 13559 KiB

Open AccessArticle

Maximum Entropy Method for Wind Farm Site Selection: Implications for River Basin Ecosystems Under Climate Change

by Muge Unal, Ahmet Cilek and Senem Tekin

Water 2024, 16(24), 3679; https://doi.org/10.3390/w16243679 - 20 Dec 2024

Abstract

As the global shift from fossil fuels to the Paris Agreement has accelerated, wind energy has become a key alternative to hydroelectric power. However, existing research often needs to improve in integrating diverse environmental, economic, and climate-related variables when modeling wind energy potential, [...] Read more.

As the global shift from fossil fuels to the Paris Agreement has accelerated, wind energy has become a key alternative to hydroelectric power. However, existing research often needs to improve in integrating diverse environmental, economic, and climate-related variables when modeling wind energy potential, particularly under future climate change scenarios. Addressing these gaps, this study employs the maximum entropy (MaxEnt) method, a robust and innovative tool for spatial modeling, to identify optimal wind farm sites in Türkiye. This research advances site selection methodologies and enhances predictive accuracy by leveraging a comprehensive dataset and incorporating climate change scenarios. The results indicate that 89% of the current licensed projects will maintain compliance in the future, while 8% will see a decrease in compliance. Furthermore, the wind energy potential in Türkiye is expected to increase because of climate change. These results confirm the suitability of existing project locations and identify new high-potential areas for sustainable wind energy development. This study provides policymakers, investors, and developers actionable insights to optimize wind energy integration into the national energy portfolio, supporting global climate goals by accelerating the adoption of renewable energy sources. Full article

(This article belongs to the Special Issue Applications of Remote Sensing and GISs in River Basin Ecosystems)

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14 pages, 7128 KiB

Open AccessArticle

Transient Flow Characterization of Rotor–Stator Cavities in Two Through-Flow Modes: Centrifugal and Centripetal

by Yulong Yao, Chuan Wang, Yitong Wang, Jie Ge, Hao Chang, Li Zhang and Hao Li

Water 2024, 16(24), 3678; https://doi.org/10.3390/w16243678 - 20 Dec 2024

Abstract

This study investigates the influence of roughness on the transient flow behavior in the chamber based on the performance requirements of the pump rotor–stator chamber, aiming to elucidate the mechanism of roughness in real operating conditions. Three-dimensional models under two types of flow [...] Read more.

This study investigates the influence of roughness on the transient flow behavior in the chamber based on the performance requirements of the pump rotor–stator chamber, aiming to elucidate the mechanism of roughness in real operating conditions. Three-dimensional models under two types of flow (centrifugal and centripetal) are developed, and transient numerical analyses are performed through numerical simulation and experimental validation. The results show that roughness significantly accelerates turbulence development in centrifugal through-flow, particularly in the middle- and high-radius regions, increasing the turbulent kinetic energy by approximately 18% compared to smooth surfaces. Transient flow analyses indicate that roughness leads to an overall pressure drop of around 10% within the cavity while facilitating the formation of high-pressure zones near the rotor. In centrifugal flow, high-pressure regions develop rapidly in the high-radius area, resulting in a stepped pressure distribution with a peak pressure increase of 12% at the outermost radius. In centripetal flow, the pressure distribution remains more uniform, yet significant pressure rise trends emerge over time, with pressure increasing by 8% due to the presence of roughness. This study presents a systematic analysis of the effects of roughness on transient flow characteristics in rotor–stator cavities across two flow modes for the first time, providing valuable insights for optimizing pump design and performance under real-world conditions. Full article

(This article belongs to the Special Issue Hydraulics and Hydrodynamics in Fluid Machinery)

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