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Water, Volume 16, Issue 7 (April-1 2024) – 158 articles

Cover Story (view full-size image): This study investigated the effects of salinity intrusion on the habitat of the clam Corbicula japonica in the Seomjin River estuarine zone. Two salinity measurement facilities were installed in Seomjin River estuarine and operated to optimize the EFDC model. The results show that reduced flow rates due to intake have a negligible impact on the increased salinity. Maintaining optimal salinity (15–20 psu) during neap tides at the Seomjin River Bridge requires constant high flow rates, which poses significant challenges. Saltwater stratification is identified as the primary cause of pronounced salinity stratification, particularly during neap tides. Addressing this issue through river discharge and intake facility operation is challenging. Structural measures, including riverbed restoration and underwater barriers, are recommended to improve resistance to seawater intrusion. View this paper
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13 pages, 592 KiB  
Article
The Use of Macrophytes for the Removal of Chlorpyrifos from the Aquatic Environment
by Elżbieta Sobiecka, Milena Mroczkowska, Tomasz P. Olejnik and Agnieszka Nowak
Water 2024, 16(7), 1071; https://doi.org/10.3390/w16071071 - 8 Apr 2024
Viewed by 672
Abstract
Phytoremediation is one of the effective technologies for removing pollutants from the aquatic environment. Toxic compounds such as chlorpyrifos can affect the physiological processes of aquatic plants, causing secondary oxidative stress in plant tissues. Macrophytes, like other organisms inhabiting the contaminated ecosystem, have [...] Read more.
Phytoremediation is one of the effective technologies for removing pollutants from the aquatic environment. Toxic compounds such as chlorpyrifos can affect the physiological processes of aquatic plants, causing secondary oxidative stress in plant tissues. Macrophytes, like other organisms inhabiting the contaminated ecosystem, have developed a system of defense mechanisms, thanks to which plants can still exist in their natural ecosystem. Our research is a summary of the previously presented results of the effectiveness of purifying contaminated water with chlorpyrifos in the phytoremediation process and the second type of phytoremediation supported by microorganisms, which intensify the process of removing contaminants from the environment. This research concerned changes in nonenzymatic and enzymatic antioxidants in Canadian seaweed, needle spikerush and water mint caused by chlorpyrifos. The research determines changes in the total concentration of polyphenols, flavonoids and dyes (chlorophyll A, chlorophyll B, anthocyanins and carotenoids) as well as differences in the activity of guaiacol peroxidase and glutathione S-transferase. The analysis of the results showed an increase in the content of polyphenols and flavonoids. The reverse trend was observed in the case of the pigment content. The appearance of chlorpyrifos in the environment caused an increase in the activity of the examined enzymes. The process involving microorganisms that were obtained from places contaminated with pesticide proved to be more effective. This shows the cooperation of species living in an investigated ecosystem. Full article
(This article belongs to the Special Issue Impact of Environmental Factors on Aquatic Ecosystem)
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16 pages, 11192 KiB  
Article
Designing the Spigot Structure of Hydrocyclones to Reduce Fine Particle Misplacement in Underflow
by Peikun Liu, Bo Chen, Duanxu Hou, Xinghua Yang, Wei Zhang and Yuanli Lu
Water 2024, 16(7), 1070; https://doi.org/10.3390/w16071070 - 8 Apr 2024
Viewed by 675
Abstract
Hydrocyclones can be used to concentrate the entrained sands in sewage and alleviate the clogging and erosion of the drainage network, but in practical application, there are problems such as low concentrations of underflow and a high content of fine particles, which cause [...] Read more.
Hydrocyclones can be used to concentrate the entrained sands in sewage and alleviate the clogging and erosion of the drainage network, but in practical application, there are problems such as low concentrations of underflow and a high content of fine particles, which cause a significant load on the subsequent sand dewatering and recycling. This paper designs five spigot structures of hydrocyclones and investigates the separation performance by numerical simulation, aiming to improve the applicability of hydrocyclones in the sewage treatment process by optimizing the spigot structure. The research results show that a large cone spigot delays the external downward swirling flow and reduces fine particle content in the underflow, but its effective separation space is reduced, and the turbulence in the cone section area is more intensive, which influences the separation accuracy. An elongated spigot has a reduced underflow water distribution; fine particles are more enriched in the internal swirling flow, and the underflow recoveries of 1 μm and 5 μm particles drop by 2.34% and 2.31%. The spigot structure affects the downward fluid and air intake states; complicated spigot structures contribute to increasing the resistance of particle discharge through underflow, alleviating fine particle misplacement. Full article
(This article belongs to the Topic Oil, Gas and Water Separation Research)
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29 pages, 17666 KiB  
Article
Use of the Gas Emission Site Type Method in the Evaluation of the CO2 Emissions in Raised Bogs
by Roman Cieśliński and Katarzyna Kubiak-Wójcicka
Water 2024, 16(7), 1069; https://doi.org/10.3390/w16071069 - 8 Apr 2024
Viewed by 695
Abstract
Peatbogs are important in global greenhouse gas budget estimates. The main aim of the work was to assess the amount of greenhouse gas emissions based on the Greenhouse Gas Emission Site Type (GEST) method and compare them with actual field measurements. The research [...] Read more.
Peatbogs are important in global greenhouse gas budget estimates. The main aim of the work was to assess the amount of greenhouse gas emissions based on the Greenhouse Gas Emission Site Type (GEST) method and compare them with actual field measurements. The research was carried out in selected peatbog areas in the coastal zone of northern Poland. The proposed method allowed us to assess whether the restoration treatments carried out in peatbogs contributed to the emission of these gases. The results of this research using the GEST method indicate that, in the studied peatbog areas, the reduction in CO2 emissions was approximately 12%. These results were compared with actual measurements of greenhouse gas emissions made using the chamber method in 2018. The average CO2 emission for the entire peatbog was 16,338.7 t CO2-eq./yr. Comparing this result with the result obtained using the GEST method, it should be stated that it is lower by 2.464.1 t CO2-eq./year, which gives an approximately 13% overestimation of the result by the Gas Emission Site Type method. Full article
(This article belongs to the Special Issue Restoration of Wetlands for Climate Change Mitigation)
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13 pages, 6961 KiB  
Article
Ephemeral Puddles—Potential Sites for Feeding and Reproduction of Hyporheic Copepoda
by Maciej Karpowicz and Sabina Smolska
Water 2024, 16(7), 1068; https://doi.org/10.3390/w16071068 - 8 Apr 2024
Viewed by 585
Abstract
The hyporheic (phreatic) zone connects groundwater and surface water and hosts a diverse community of organisms that are adapted to its unique conditions. In order to investigate the hitherto poorly understood biotic connections between the hyporheic zone and temporary ponds, we analyzed changes [...] Read more.
The hyporheic (phreatic) zone connects groundwater and surface water and hosts a diverse community of organisms that are adapted to its unique conditions. In order to investigate the hitherto poorly understood biotic connections between the hyporheic zone and temporary ponds, we analyzed changes in the community of Copepoda in a small and shallow ephemeral puddle in a meadow for one year, with comparison to the groundwater fauna of the surrounding region in northeastern Poland. In the puddle, three species of Cyclopoida (Acanthocyclops vernalis, Diacyclops bisetosus, and Cyclops furcifer) were present in large numbers throughout the year. These species were also common components of the region’s groundwater fauna, but in much lower densities in the groundwater than in the puddle. These results suggest that temporary puddles can be a convenient place for copepods to feed and reproduce, while groundwater may serve as an important corridor for their dispersal. This study contributes to a more comprehensive understanding of copepod ecology and the functioning of ephemeral aquatic habitats. Full article
(This article belongs to the Section Ecohydrology)
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19 pages, 34334 KiB  
Article
Hydrogeological Investigation of a Goaf and Subsidence Area Based on a Ground-to-Air Transient Electromagnetic Sounding Method
by Qicai Feng, Chang Li, Shuren Hao, Dongsheng Li, Tao Liu, Zhonglin Sun and Ling Zhou
Water 2024, 16(7), 1067; https://doi.org/10.3390/w16071067 - 7 Apr 2024
Viewed by 667
Abstract
Water hazards in coal mines have always been the main geological hazard that restricts the safety of coal mine production. The traditional electromagnetic method is difficult to accurately detect the hydrogeological conditions of underground goafs due to accuracy and interference problems. The ground-to-air [...] Read more.
Water hazards in coal mines have always been the main geological hazard that restricts the safety of coal mine production. The traditional electromagnetic method is difficult to accurately detect the hydrogeological conditions of underground goafs due to accuracy and interference problems. The ground-to-air transient electromagnetic method is an electromagnetic detection technology with strong adaptability to various terrains, a large detection depth, a wide coverage, a high resolution, and fast speed. This paper mainly applies the ground-to-air transient electromagnetic method to conduct a hydrogeological engineering geological survey in a mine subsidence area. By using this method effectively, changes in hydrogeological and engineering geological conditions in the mine subsidence area are identified and water filling conditions below section 310 and section 250 of the roadway are determined. This study provides accurate and reliable basic data support for rescue operations and post-disaster reconstruction efforts, while also offering valuable insights for similar exploration projects. Full article
(This article belongs to the Special Issue Effects of Groundwater and Surface Water on the Natural Geo-Hazards)
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25 pages, 2648 KiB  
Article
A Novel Modeling Approach to Quantify the Flood Resilience of Cities
by Wenping Xu, Wenwen Du, David Proverbs and Xinyan Cai
Water 2024, 16(7), 1066; https://doi.org/10.3390/w16071066 - 7 Apr 2024
Viewed by 633
Abstract
In recent years, large-scale flood events have occurred more frequently, and the concept of resilience has become a prevalent approach to managing flood risk in many regions. This has led to an increased interest in how to effectively measure a city’s flood resilience [...] Read more.
In recent years, large-scale flood events have occurred more frequently, and the concept of resilience has become a prevalent approach to managing flood risk in many regions. This has led to an increased interest in how to effectively measure a city’s flood resilience levels. This study proposes a novel modeling approach to quantify urban flood resilience by developing D-number theory and analytical hierarchy process (AHP) models, which are applied to three cities in China using the VIse Kriterijumski Optimizacioni Racun (VIKOR) method. The findings reveal that Hefei City has the most effective level of flood resilience, Hangzhou City was ranked second, while Zhengzhou City has the least effective level of flood resilience. This study provides a new scientific basis on how to quantify flood resilience at the city scale and provides a useful reference for these three specific cities. The methods and approaches developed in this study have the potential to be applied to other cities and in the related aspects of disaster prevention, recovery, and reconstruction. Full article
(This article belongs to the Section Urban Water Management)
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13 pages, 3517 KiB  
Article
Effects of Ecological Water Diversion on Internal Nitrogen and Phosphorus Release in a Typical Small Shallow Lake in China
by Huaizhi Chen, Yunben Li, Anjie Wu, Yadong Wang, Yanping Zhao, Guoxiang Wang, Chao Han and Qiushi Shen
Water 2024, 16(7), 1065; https://doi.org/10.3390/w16071065 - 7 Apr 2024
Viewed by 672
Abstract
Ecological water diversion is an important method to improve water quality in lakes and reservoirs. But the environmental effects, from the ecological water diversion project (EWDP) to the internal release of sediment nutrients, remain unclear. In this study, an indoor simulation of an [...] Read more.
Ecological water diversion is an important method to improve water quality in lakes and reservoirs. But the environmental effects, from the ecological water diversion project (EWDP) to the internal release of sediment nutrients, remain unclear. In this study, an indoor simulation of an EWDP with different treatment scenarios with water transfer proportions of 25%, 50%, 75% and 100% was conducted to study the effects of water diversion on sediment nitrogen and phosphorus release in Lake Wanshandang. Our results showed that the flux of NH3–N released from the sediments in the western and eastern areas of Lake Wanshandang was significantly reduced after water transfer treatment, and the degree of reduction increased with increased water transfer. Specifically, the release flux of NH3–N in the sediment in the western area decreased from 18.02 mg/(m2/d) to −2.25 mg/(m2/d) when the transferred water reached 100% replacement of the original overlying water. The effect of water transfer treatment on the release flux of SRP from sediment varied greatly throughout the lake. After treatment, the SRP release flux in the western and central areas increased significantly, while it decreased in the eastern area. The NH3–N and SRP concentrations changed from 0.12–0.27 mg/L and 0.02–0.049 mg/L to 0.28–0.84 mg/L and 0.01–0.066 mg/L before and after the water transfer treatment. Our statistical analysis showed that the change in NH3–N and SRP release fluxes after treatment was significantly negatively correlated (p < 0.05) with concentrations of NH3–N or SRP in the overlying water before and after water transfer. We suggest the increase in NH3–N and SRP concentrations in the overlying water after the water transfer treatment led to the subsequent decreased NH3–N or SRP release flux, while the decrease in SRP concentration in overlying waters enhanced SRP release from the sediment. The differences in the concentrations of nitrogen and phosphorus between the original overlying water and the transferred incoming water are important factors affecting the release of nutrients from sediment. Full article
(This article belongs to the Special Issue Internal Nutrient Cycling in Lakes and Reservoirs)
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16 pages, 6074 KiB  
Article
Dynamic Bayesian-Network-Based Approach to Enhance the Performance of Monthly Streamflow Prediction Considering Nonstationarity
by Wen Zhang, Pengcheng Xu, Chunming Liu, Hongyuan Fang, Jianchun Qiu and Changsheng Zhang
Water 2024, 16(7), 1064; https://doi.org/10.3390/w16071064 - 7 Apr 2024
Viewed by 624
Abstract
In recognizing the pervasive nonstationarity of hydrometeorological variables, a paradigm shift towards alternative analytical methodologies is imperative for refining hydroclimatic data modeling and prediction. We introduce a novel approach leveraging nonstationary Graphical Modeling and Bayesian Networks (NGM-BNs) tailored for hydrometeorological applications. Demonstrated through [...] Read more.
In recognizing the pervasive nonstationarity of hydrometeorological variables, a paradigm shift towards alternative analytical methodologies is imperative for refining hydroclimatic data modeling and prediction. We introduce a novel approach leveraging nonstationary Graphical Modeling and Bayesian Networks (NGM-BNs) tailored for hydrometeorological applications. Demonstrated through monthly streamflow forecasting in the Kashgar River Basin of China, our method illuminates the temporal evolution of network relationships, underscoring the dynamism inherent in both input variables and modeling parameters. The key to our approach is identifying the most suitable time horizon (MST) for model updates, which is intricately problem-specific and crucial for peak performance. This methodology not only unveils changing predictor significance across varying flow conditions but also elucidates the fluctuating temporal links between variables, especially under the lens of climate change, for instance, the growing impact of snowmelt on the Kashgar Basin’s streamflow. Compared to stationary counterparts, our nonstationary Bayesian framework excels in capturing extreme events by adeptly accommodating temporal shifts, outperforming traditional models including both stationary and nonstationary variants of Support Vector Regression (SVR) and Adaptive Neuro-Fuzzy Inference Systems (ANFIS). Full article
(This article belongs to the Special Issue Hydraulic Engineering and Ecohydrology)
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18 pages, 6522 KiB  
Article
Suspended Sediment Source and Transport Mechanisms in a Himalayan River
by Sanyam Ghimire, Umesh Singh, Krishna Kanta Panthi and Pawan Kumar Bhattarai
Water 2024, 16(7), 1063; https://doi.org/10.3390/w16071063 - 7 Apr 2024
Viewed by 1539
Abstract
The process of estimating sediment load has been a daunting issue in hydraulics and the water resource field. Several methods exist for predicting the sediment load in a catchment or river, but the majority of these methods are empirical and depend on the [...] Read more.
The process of estimating sediment load has been a daunting issue in hydraulics and the water resource field. Several methods exist for predicting the sediment load in a catchment or river, but the majority of these methods are empirical and depend on the specific location where they are used. Understanding the underlying mechanism of sediment generation and its transport in connection with precipitation, topography, and subsurface conditions to characterize its process is helpful for determining the sediment load in a river. For this purpose, we analyzed the daily suspended sediment data measured for 8 years at the headworks of the Kabeli A hydropower project in the Kabeli River, which originates from the Himalayan region. The analyses show that the suspended sediment concentration (SSC) varies in an orderly manner over time and asynchronously between seasons with respect to the river discharge. Clockwise hysteresis is observed in the yearly plots between the SSC and river discharge. The hysteresis becomes narrower when compared with the direct runoff obtained from a digital filtering algorithm and, even more so with the direct runoff from the hydrological model SWAT. The analysis shows that the sediment concentration is controlled not only by the total discharge in the river but also by the contribution of ground water to the river discharge, indicating that the total discharge alone cannot reflect the seasonal variation in SSC. It is inferred that the river is supply-limited and the hillslope is transport-limited with respect to sediment sources. The SWAT model suggests that the base flow contribution to the total river discharge is 78%. Here, we present a method for constructing the suspended sediment rating curve by comparing the direct runoff with the sediment concentration. The deduced sediment rating curve captures 84.51% of the total sediment load over the study period in the Kabeli River. This method may potentially be used in similar catchments with supply-limited rivers and transport-limited hillslopes. Full article
(This article belongs to the Section Hydrology)
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16 pages, 1265 KiB  
Article
Application and Research of Microseismic Monitoring System and Hydraulic Fracturing Technology in Coal Mines
by Hui Sun, Na He and Filip Gurkalo
Water 2024, 16(7), 1062; https://doi.org/10.3390/w16071062 - 7 Apr 2024
Viewed by 657
Abstract
In order to improve the effectiveness of coal mine gas control and enhance the level of coal mine safety production, the application of a microseismic monitoring system and hydraulic fracturing technology in coal mines was studied. Applying hydraulic fracturing technology to coal mine [...] Read more.
In order to improve the effectiveness of coal mine gas control and enhance the level of coal mine safety production, the application of a microseismic monitoring system and hydraulic fracturing technology in coal mines was studied. Applying hydraulic fracturing technology to coal mine gas treatment, firstly, the geological structure and gas concentration in the mining area are detected using the radio tunnel perspective method and infrared differential absorption method. Then, the relevant parameters of hydraulic fracturing are determined, and finally, hydraulic fracturing technology is implemented. Microseismic monitoring technology is used to monitor the cracks formed during hydraulic fracturing construction and evaluate the fracturing effect. The instantaneous energy envelope is obtained from the microseismic data of each detection channel after stacking and Hilbert transform static correction. A microseismic in-phase inversion positioning objective function based on travel time residuals is constructed, and under the constraints of polarization analysis, the optimal solution is obtained through search iteration to complete microseismic in-phase inversion positioning. Experimental results have shown that after applying this method to coal mine gas control, the gas concentration decreases below the execution standard, achieving good control effects. Under microseismic monitoring in coal mines, the hydraulic fracturing effect can be effectively and reasonably evaluated, and the safety production level of coal mines can be improved. Full article
(This article belongs to the Special Issue Mine Water Safety and Environment)
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25 pages, 1668 KiB  
Article
Hydropower Politics in Northeast India: Dam Development Contestations, Electoral Politics and Power Reconfigurations in Sikkim
by Rinchu Doma Dukpa, Jaime Hoogesteger, Gert Jan Veldwisch and Rutgerd Boelens
Water 2024, 16(7), 1061; https://doi.org/10.3390/w16071061 - 6 Apr 2024
Viewed by 862
Abstract
Around the world, the development of large dams has been increasingly contested. India is no exception and has seen the mobilisation of powerful domestic and transnational socio-environmental movements against dams over more than four decades. In this context, the State of Sikkim in [...] Read more.
Around the world, the development of large dams has been increasingly contested. India is no exception and has seen the mobilisation of powerful domestic and transnational socio-environmental movements against dams over more than four decades. In this context, the State of Sikkim in northeast India has been entangled in prolonged hydropower development conflicts since the late 1990s. This article analyses these conflictive entanglements between the Government of India, the State Government of Sikkim, power companies and Sikkim’s autochthonous tribe, the Lepchas. It zooms in on the period of 2011–2017, which saw an abrupt escalation of the conflicts to analyse the messy, deeply political and often unpredictable and contradictory world of dam construction and its contestations. Our analysis is informed by the power cube framework developed by John Gaventa. Our analysis shows how hydropower development is deeply intertwined with local patronage relationships. We show how local elections bring out dam conflict and the operation of power into the open, sometimes leading to abrupt and unexpected switches in positions in relation to hydropower development. We show that these switches should be seen not only as “strategic electoral tactics” but also and importantly as contentious political struggles that (re)configure power in the region. We show how in this process, powerful political actors continuously seek to stabilise power relations among the governing and the governed, choreographing a specific socio-hydraulic order that stretches way beyond simple pro- and anti-dam actors and coalitions as it is embedded in deep hydro(-electro) politics and power plays. Full article
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20 pages, 2187 KiB  
Article
A Boatable Days Framework for Quantifying Whitewater Recreation—Insights from Three Appalachian Whitewater Rivers
by Nicolas Zegre, Melissa Shafer, Danny Twilley, Greg Corio, Michael P. Strager, Jacquelyn M. Strager and Paul Kinder
Water 2024, 16(7), 1060; https://doi.org/10.3390/w16071060 - 6 Apr 2024
Viewed by 1158
Abstract
Outdoor recreation is one of the fastest-growing economic sectors in the United States and is being used by communities to support economic development, social prosperity, and environmental protection. For communities that have whitewater rivers, whitewater recreation provides a powerful economic alternative to ailing [...] Read more.
Outdoor recreation is one of the fastest-growing economic sectors in the United States and is being used by communities to support economic development, social prosperity, and environmental protection. For communities that have whitewater rivers, whitewater recreation provides a powerful economic alternative to ailing extractive and manufacturing industries that have long dominated rural communities. In order to promulgate a whitewater recreation-based economy, stakeholders need information about their whitewater resources, including how often and when they can be paddled. The overall goal of this study, therefore, was to develop an analytical framework that quantifies boatable days, that is, the number of days that streamflow exceeds the minimum boatable flow levels needed to paddle downstream. Importantly, our framework uses publicly available streamflow and minimum boatable flow information that can be used to quantify boatable days for any whitewater run in the country, irrespective of watershed size or river flashiness. We applied the framework to three world-class whitewater rivers in the central Appalachian Mountains, USA, and found abundant and stable boating opportunities throughout the year. Our results underscore the potential for strategically developing whitewater recreation as a means of economic diversification and highlight how boatable days analysis can be used for quantifying whitewater resources. Full article
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17 pages, 3146 KiB  
Article
On the Use of Weather Generators for the Estimation of Low-Frequency Floods under a Changing Climate
by Carles Beneyto, José Ángel Aranda and Félix Francés
Water 2024, 16(7), 1059; https://doi.org/10.3390/w16071059 - 6 Apr 2024
Viewed by 796
Abstract
The present work presents a methodology based on the use of stochastic weather generators (WGs) for the estimation of high-return-period floods under climate change scenarios. Applying the proposed methodology in a case study, Rambla de la Viuda (Spain), satisfactory results were obtained through [...] Read more.
The present work presents a methodology based on the use of stochastic weather generators (WGs) for the estimation of high-return-period floods under climate change scenarios. Applying the proposed methodology in a case study, Rambla de la Viuda (Spain), satisfactory results were obtained through the regionalization of the bias-corrected EUROCORDEX climate projections and the integration of this information into the parameterization of the WG. The generated synthetic data series fed a fully distributed hydrological model to obtain the future flood quantiles. The results obtained show a clear increase in the precipitation extreme quantiles for the two analyzed projections. Although slightly reducing the annual amount of precipitation, variations between 4.3% for a return period of 5 years in the mid-term projection and 19.7% for a return period of 100 years in the long-term projection have been observed. In terms of temperatures, the results point to clear increases in the maximum and minimum temperatures for both projections (up to 3.6 °C), these increases being greater for the long-term projection, where the heat waves intensify significantly in both magnitude and frequency. Finally, although rivers may present, in general, with lower flows during the year, flood quantiles experience an increase of 53–58% for high return periods, which reach values of up to 145% when we move to smaller catchments. All this combined translates into substantial shifts in the river flow regimes, increasing the frequency and magnitude of extreme flood events. Full article
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19 pages, 4023 KiB  
Article
The Impact of the Water Tariff on the Economic Feasibility of Rainwater Harvesting for Use in Residential Buildings
by Aline Eloize Borgert and Enedir Ghisi
Water 2024, 16(7), 1058; https://doi.org/10.3390/w16071058 - 6 Apr 2024
Viewed by 620
Abstract
This study aims to analyse the technical viability and economic feasibility of rainwater-harvesting systems for single- and multifamily residential buildings in the city of Florianópolis, Brazil. Simulations were conducted for representative buildings in the city under different water-usage scenarios and system designs, in [...] Read more.
This study aims to analyse the technical viability and economic feasibility of rainwater-harvesting systems for single- and multifamily residential buildings in the city of Florianópolis, Brazil. Simulations were conducted for representative buildings in the city under different water-usage scenarios and system designs, in a total of 36 simulation scenarios. An economic analysis was performed for four scenarios over a twenty-year period. Both initial and operational costs were considered, and the net present value, internal rate of return, and payback were used as feasibility indicators. For houses, between 60.1% and 74.8% of the cases were economically feasible, achieving a discounted payback period ranging from 6.2 to 8.6 years. For flats, between 57.8% and 64.2% of the cases were economically feasible, achieving a discounted payback period ranging from 4.8 to 5.6 years. As the water tariff in the city underwent changes recently, the former and current tariff formats were compared. The current tariff format provides more economic benefits for saving potable water, and leads to a higher net present value and a shorter discounted payback period. This research stands out from previous studies as it examines a new scenario in the use of rainwater-harvesting systems. Full article
(This article belongs to the Special Issue Rainwater Harvesting and Treatment)
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14 pages, 2676 KiB  
Article
Water Colour Changes in High-Elevation Alpine Lakes during 2017–2022: A Case Study of the Upper Orco Valley Catchment
by Erica Matta, Mariano Bresciani, Claudia Giardino, Marta Chiarle and Guido Nigrelli
Water 2024, 16(7), 1057; https://doi.org/10.3390/w16071057 - 6 Apr 2024
Viewed by 674
Abstract
The water resource is severely compromised by climate change, and its availability and quality can no longer be taken for granted, even in places considered pristine, such as mountains. In this study, we evaluated the water colour variability of three artificial mountain lakes [...] Read more.
The water resource is severely compromised by climate change, and its availability and quality can no longer be taken for granted, even in places considered pristine, such as mountains. In this study, we evaluated the water colour variability of three artificial mountain lakes located in a relatively small basin (Western Italian Alps) at high elevations, and related this variability to the local climate conditions of the hydrological basin to which they belong. We estimated the dominant wavelength (DW) of lake water from Sentinel-2 acquisitions for the period 2017–2022, performing a chromaticity analysis. We correlated DW with climatic parameters recorded by two automated weather stations. Average DW varies from 497 nm of Serrù Lake and Agnel Lake to 512 nm of Lake Ceresole, where DW varies seasonally (variation of 75–100 nm in one year). During April–July, the DW of Lake Ceresole is significative correlated with air temperatures and snow cover (−0.8 and +0.8, respectively). During August–October, the relationship with temperature decreases to −0.5, and a correlation of 0.5 with the amount of rainfall appears. This work shows that mountain lake waters can exhibit variable quality (expressed here by water colour) in response to meteorological and hydrological conditions and events. Full article
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25 pages, 6180 KiB  
Article
Assessing and Improving the Robustness of Bayesian Evidential Learning in One Dimension for Inverting Time-Domain Electromagnetic Data: Introducing a New Threshold Procedure
by Arsalan Ahmed, Lukas Aigner, Hadrien Michel, Wouter Deleersnyder, David Dudal, Adrian Flores Orozco and Thomas Hermans
Water 2024, 16(7), 1056; https://doi.org/10.3390/w16071056 - 6 Apr 2024
Viewed by 763
Abstract
Understanding the subsurface is of prime importance for many geological and hydrogeological applications. Geophysical methods offer an economical alternative for investigating the subsurface compared to costly borehole investigations. However, geophysical results are commonly obtained through deterministic inversion of data whose solution is non-unique. [...] Read more.
Understanding the subsurface is of prime importance for many geological and hydrogeological applications. Geophysical methods offer an economical alternative for investigating the subsurface compared to costly borehole investigations. However, geophysical results are commonly obtained through deterministic inversion of data whose solution is non-unique. Alternatively, stochastic inversions investigate the full uncertainty range of the obtained models, yet are computationally more expensive. In this research, we investigate the robustness of the recently introduced Bayesian evidential learning in one dimension (BEL1D) for the stochastic inversion of time-domain electromagnetic data (TDEM). First, we analyse the impact of the accuracy of the numerical forward solver on the posterior distribution, and derive a compromise between accuracy and computational time. We also introduce a threshold-rejection method based on the data misfit after the first iteration, circumventing the need for further BEL1D iterations. Moreover, we analyse the impact of the prior-model space on the results. We apply the new BEL1D with a threshold approach on field data collected in the Luy River catchment (Vietnam) to delineate saltwater intrusions. Our results show that the proper selection of time and space discretization is essential for limiting the computational cost while maintaining the accuracy of the posterior estimation. The selection of the prior distribution has a direct impact on fitting the observed data and is crucial for a realistic uncertainty quantification. The application of BEL1D for stochastic TDEM inversion is an efficient approach, as it allows us to estimate the uncertainty at a limited cost. Full article
(This article belongs to the Special Issue Application of Geophysical Methods for Hydrogeology)
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30 pages, 12227 KiB  
Article
Spatio-Temporal Morphodynamics of a Nourished Sandy Shore Based on LiDAR Measurements
by Marek Harenda, Aleksandra Dudkowska and Piotr Szmytkiewicz
Water 2024, 16(7), 1055; https://doi.org/10.3390/w16071055 - 6 Apr 2024
Viewed by 655
Abstract
Coastal erosion is a pervasive global phenomenon, exemplified by the Hel Peninsula situated in the Gulf of Gdańsk, the southern Baltic Sea. The geological constitution of the Hel Peninsula, characterized by sandy and loosely consolidated material, predisposes its coastal zones to continual morphological [...] Read more.
Coastal erosion is a pervasive global phenomenon, exemplified by the Hel Peninsula situated in the Gulf of Gdańsk, the southern Baltic Sea. The geological constitution of the Hel Peninsula, characterized by sandy and loosely consolidated material, predisposes its coastal zones to continual morphological changes. The peninsula’s limited width and elevation exacerbate shoreline erosion, particularly during periods of heightened storm activity. This study scrutinizes the effectiveness of coastal nourishment interventions, with a specific focus on segments influenced by the Władysławowo port and the Kuźnica vicinity, over several years. This specific section of the coast serves as a significant case study due to its role as a transit zone for sand transport along the whole peninsula. Protective measures, including shore nourishments and coastal groynes, aim to mitigate erosion impacts. Utilizing Airborne Laser Scanning (ALS) data spanning from 2008 to 2022, erosion dynamics were analyzed. The analysis reveals significant erosion patterns coinciding with the frequency and volume of nourishment material deposition, particularly evident in heavily nourished areas proximate to Władysławowo and Kuźnica. Despite persistent monitoring endeavors, persistent erosive trends pose imminent threats to Kuźnica’s infrastructure, necessitating further research into the efficacy of implemented coastal protection measures. Full article
(This article belongs to the Special Issue Coastal Sediments: Processes, Transport, Modeling and Hydrodynamics)
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13 pages, 2817 KiB  
Article
Treatment Effect of Long-Term Subsurface-Flow Constructed Wetland on Mariculture Water and Analysis of Wetland Bacterial Community
by Chen Chen, Guijun Yang, Xuechu Chen, Pengquan Li, Jingfei Chen, Maocang Yan and Chong Guo
Water 2024, 16(7), 1054; https://doi.org/10.3390/w16071054 - 6 Apr 2024
Viewed by 618
Abstract
To improve the quality of natural seawater to meet the needs of aquaculture production, a large-scale subsurface-flow constructed wetland (HSFCW) was constructed and operated stably for 2 years to understand the reasons for its purification effect on natural seawater. The results of the [...] Read more.
To improve the quality of natural seawater to meet the needs of aquaculture production, a large-scale subsurface-flow constructed wetland (HSFCW) was constructed and operated stably for 2 years to understand the reasons for its purification effect on natural seawater. The results of the study showed that the system could maintain a high purification effect on natural seawater during aquaculture; the average removal rates of COD, TSS, TN, NH4+-N, and DON (organic nitrogen) were 22.29%, 49.33%, 36.94%, 10.88%, and 44.08%, respectively. Additionally, the HSFCW could effectively remove harmful algae such as Cyanobacteria; the removal rate of dominant algae species in Cyanobacteria was 90.33–97.93%. The pyrosequencing of 16S ribosomal DNA revealed that Proteobacteria, Nitrospirae, and Chloroflexi were the main and key bacterial phyla in the system. Members of these key gates are regarded as playing important roles in resisting water purification. The study results suggest that the subsurface-flow wetland system can effectively improve seawater quality and reduce the density of harmful algae cells. Full article
(This article belongs to the Special Issue Water Quality in Aquaculture Production)
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20 pages, 6695 KiB  
Article
Morphometric Analysis Using Geographical Information System and the Relationship with Precipitation Quantiles of Major Dam Basins in South Korea
by Sejeong Oh, Jinwook Lee, Jongjin Baik, Changhyun Jun and Eui Hoon Lee
Water 2024, 16(7), 1053; https://doi.org/10.3390/w16071053 - 6 Apr 2024
Viewed by 605
Abstract
Geographic information system (GIS) and remote sensing (RS) technologies are potent tools for evaluating various aspects of basin hydrology. This study conducted a morphological analysis using GIS tools on seven major dam basins in Korea. Additionally, long-term RS-based precipitation data were obtained, the [...] Read more.
Geographic information system (GIS) and remote sensing (RS) technologies are potent tools for evaluating various aspects of basin hydrology. This study conducted a morphological analysis using GIS tools on seven major dam basins in Korea. Additionally, long-term RS-based precipitation data were obtained, the probability of precipitation was estimated, and their relationship was examined. The findings are summarized as follows. It was observed that most major dam basins in Korea, which were the focus of this study, had a broad radial shape, and due to the mountainous topography, there was a notable presence of numerous river branches. Through the estimation of probability precipitation and its comparison with morphological indices, it was noted that wider basins tend to have higher rainfall amounts and a relatively uniform spatial distribution. Furthermore, it was found that the more uniform the spatial distribution, the simpler the river network. This trend becomes more pronounced in relation to basin size for longer durations, and in spatial dispersion for shorter durations. However, it is crucial to acknowledge that the complexity of these relationships is also affected by other factors such as climate, altitude, and local geographical conditions. Full article
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20 pages, 1334 KiB  
Review
Salinity-Induced Changes in Heavy Metal Behavior and Mobility in Semi-Arid Coastal Aquifers: A Comprehensive Review
by Rakesh Roshan Gantayat and Vetrimurugan Elumalai
Water 2024, 16(7), 1052; https://doi.org/10.3390/w16071052 - 5 Apr 2024
Viewed by 968
Abstract
Semi-arid coastal aquifers face critical challenges characterized by lower rainfall, higher evaporation rates, and looming risk of over-exploitation. These conditions, coupled with climate change, are conducive to seawater intrusion and promote mechanisms associated with it. The understanding of metal behavior in such environments [...] Read more.
Semi-arid coastal aquifers face critical challenges characterized by lower rainfall, higher evaporation rates, and looming risk of over-exploitation. These conditions, coupled with climate change, are conducive to seawater intrusion and promote mechanisms associated with it. The understanding of metal behavior in such environments is limited, and hence, an attempt is made through this review to bridge the knowledge gap. A study on the behavior of trace metals within a specific context of semi-arid coastal aquifers was carried out, and 11 aquifers from 6 different countries were included. The review observed that trace metals within semi-arid coastal aquifers exhibit distinctive behaviors influenced by their surrounding environment. The prevalence of evaporation and continuous seawater intrusion played a pivotal role in shaping trace metal dynamics by curtailing groundwater flux. The findings suggest that the formation of stable Cl and organic ligands under increased alkaline conditions (pH > 8) has higher control over Zn, Pb, and Cd toxicity in a highly ionic reactive condition. In addition, dominant control of Fe/Mn-hydroxide association with Pb and high organic affinity of Zn played a pivotal role in controlling its bioavailability in aquifers such as WFB, Saudi Arabia NW-C and India. On the contrary, under prevailing acidic conditions (pH < 6), carbonate and SO4-ligands become more dominant, controlling the bioavailability/desorption of Cu irrespective of its origin. The behavior of Ni is found to be controlled by stable organic ligands increasing salinity. An increase in salinity in the considered aquifers shows an increase in bioavailability of Ni, except UmC, South Africa, where organic ligands act as a sink for the metal, even at low pH conditions (pH < 5.5). This study indicates that factors such as mineral saturation, carbonate complexes, pH variations (pH > 8), and chloride complexes govern the distribution of trace metals further enhanced by prolonged water residence time. Nonetheless, specific conditions, such as a reducing and acidic environment, could potentially elevate the solubility of highly toxic Cr (VI) released from anthropogenic sources. Full article
(This article belongs to the Special Issue Recent Advances in Hydrogeology: Featured Reviews)
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25 pages, 2862 KiB  
Article
Monitoring of Microplastics in Water and Sediment Samples of Lakes and Rivers of the Akmola Region (Kazakhstan)
by Natalya S. Salikova, Javier Rodrigo-Ilarri, Lyudmila A. Makeyeva, María-Elena Rodrigo-Clavero, Zhulduz O. Tleuova and Anar D. Makhmutova
Water 2024, 16(7), 1051; https://doi.org/10.3390/w16071051 - 5 Apr 2024
Cited by 1 | Viewed by 713
Abstract
This paper provides a detailed description of the findings and methodology related to the monitoring of microplastics in three lakes and one river of the Akmola Region in Kazakhstan. The concentration of microplastic particles and the analysis of water and sediment quality of [...] Read more.
This paper provides a detailed description of the findings and methodology related to the monitoring of microplastics in three lakes and one river of the Akmola Region in Kazakhstan. The concentration of microplastic particles and the analysis of water and sediment quality of the Yesil River and Kopa, Zerendinskoye, and Borovoe lakes have been analyzed. A total of 64 water samples were collected across the spring, summer, and autumn seasons, with subsequent analysis revealing a seasonal increase in microplastic concentrations. The average microplastic content ranged from 1.2 × 10−1 particles/dm3 in spring to 4.5 × 10−1 particles/dm3 in autumn. Lakes exhibited higher concentrations compared to the Yesil River. Correlation analysis highlighted a connection between microplastic content and turbidity, particularly notable during the spring season. Analysis of sediments revealed a decrease in microplastic concentrations from the coastal zone toward open waters sediments. Microplastic fibers were predominant in sediments (69.6%), followed by fragments (19.1%), films (7.4%), and granules (3.9%). Larger particles (>500 µm) were found in beach sediments, constituting an average of 40.5% of the total plastics found. This study contributes valuable insights into the spatial and temporal distribution of microplastics, emphasizing the need for ongoing monitoring and management strategies to address this environmental concern. Full article
(This article belongs to the Topic Microplastics Pollution)
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15 pages, 4180 KiB  
Article
Research on the Ecological Restoration Effects of a Vallisneria natans (Lour.) Hara-Dominated Multitrophic Level Ecosystem
by Bin Li, Zheng Han, Ruitong Jiang, Qingjie Cai, Meiqiong Zhang, Rong Wang, Yuchao Liu, Liu Shao, Meiqin Wu, Jianheng Zhang, Wenhui He, Jinlin Liu and Peimin He
Water 2024, 16(7), 1050; https://doi.org/10.3390/w16071050 - 5 Apr 2024
Viewed by 725
Abstract
This study aims to assess the ecological restoration effects of Vallisneria natans in a multitrophic level ecosystem. The water-purification effects of two hierarchical configuration modes of V. natans-Bellamya aeruginosa and V. natans-B. aeruginosa-Hyriopsis cumingii were studied. Results show that a V. natans and B. [...] Read more.
This study aims to assess the ecological restoration effects of Vallisneria natans in a multitrophic level ecosystem. The water-purification effects of two hierarchical configuration modes of V. natans-Bellamya aeruginosa and V. natans-B. aeruginosa-Hyriopsis cumingii were studied. Results show that a V. natans and B. aeruginosa configuration ratio of 15:2 stabilizes water quality at Grade IV (TN ≤ 1.5 mg/L, TP ≤ 0.3 mg/L), and increasing B. aeruginosa density significantly reduces total phosphorus. The V. natans, B. aeruginosa, and H. cumingii configuration at 15:2:10 stabilizes water at Grade III (TN ≤ 1.0 mg/L, TP ≤ 0.2 mg/L), with a positive correlation between H. cumingii density and chlorophyll-a removal. Furthermore, the filtration and biocycling actions of B. aeruginosa (snails) and H. cumingii (mussels) significantly reduce levels of Total Nitrogen (TN), Total Phosphorus (TP), and Ammonium (NH4+-N) in water, thus enhancing the self-purification capacity of the water bodies. However, the bioturbation effect of H. cumingii can temporarily increase phosphorus release from sediments, leading to a short-term rise in TP concentration in the water. Overall, the study concludes that multitrophic level ecosystems are effective in purifying water quality and offer significant ecological restoration benefits. This research provides crucial data support for future construction and ecological restoration projects involving multitrophic level approaches in China’s rivers and lakes. Full article
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20 pages, 38835 KiB  
Article
Coupled DSSAT and HYDRUS-1D Simulation of the Farmland–Crop Water Cycling Process in the Dengkouyangshui Irrigation District
by Jie Zhou, Delong Tian, Haibin Shi, Bing Xu, Zhonghou Zheng, Fan Wang, Guoshuai Wang and Xiangyang Miao
Water 2024, 16(7), 1049; https://doi.org/10.3390/w16071049 - 5 Apr 2024
Viewed by 672
Abstract
(1) Background: Effective water management in agricultural systems poses a significant challenge, particularly in the Dengkouyangshui irrigation district. Inefficiencies and insufficient detail in water usage across crop growth stages have resulted in suboptimal water cycling. Recent infrastructure improvements and technological interventions necessitate a [...] Read more.
(1) Background: Effective water management in agricultural systems poses a significant challenge, particularly in the Dengkouyangshui irrigation district. Inefficiencies and insufficient detail in water usage across crop growth stages have resulted in suboptimal water cycling. Recent infrastructure improvements and technological interventions necessitate a reevaluation of water usage, especially concerning changes in irrigation and seepage dynamics. (2) Methods: This study addresses these concerns by employing an integrated modeling approach that combines the DSSAT with the HYDRUS-1D soil hydrology model to simulate complex interactions among soil, crop growth, and irrigation practices within the district. Observational data were used to calibrate and validate the integrated model, including soil moisture, LAI, and crop yields from the 2022 and 2023 agricultural seasons. (3) Results: The simulation results strongly align with the empirical data, highlighting the ability of the model to capture the intricate dynamics of soil–water–atmosphere–plant interactions. (4) Conclusions: The soil’s retention and moisture-holding characteristics exhibited resilience during periods without water supplementation, with measurable declines in soil moisture at various depths, indicating the soil’s capacity to support crops in water-limited conditions. This study delineates water consumption by maize crops throughout their growth cycle, providing insights into evapotranspiration partitioning and quantifying seepage losses. An in-depth analysis of water balances at different growth stages informs irrigation strategies, suggesting optimal volumes to enhance efficiency during critical crop development phases. This integrative modeling approach is valuable for providing actionable data to optimize the water cycling process and improve agricultural sustainability in the Dengkouyangshui irrigation district. Full article
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21 pages, 15841 KiB  
Article
Coastal Groundwater Bodies Modelling Using Geophysical Surveys: The Reconstruction of the Geometry of Alluvial Plains in the North-Eastern Sicily (Italy)
by Patrizia Capizzi, Raffaele Martorana, Alessandro Canzoneri, Alessandro Bonfardeci and Rocco Favara
Water 2024, 16(7), 1048; https://doi.org/10.3390/w16071048 - 5 Apr 2024
Viewed by 897
Abstract
The integration of various geophysical methodologies is considered a fundamental tool for accurately reconstructing the extent and shape of a groundwater body and for estimating the physical parameters that characterize it. This is often essential for the management of water resources in areas [...] Read more.
The integration of various geophysical methodologies is considered a fundamental tool for accurately reconstructing the extent and shape of a groundwater body and for estimating the physical parameters that characterize it. This is often essential for the management of water resources in areas affected by geological and environmental hazards. This work aims to reconstruct the pattern and extent of two groundwater bodies, located in the coastal sectors of the North-Eastern Sicily, through the integrated analysis and interpretation of several geoelectrical, seismic and geological data. These are the Sant’Agata-Capo D’Orlando (SCGWB) and the Barcelona-Milazzo (BMGWB) Groundwater Bodies, located at the two ends of the northern sector of the Peloritani geological complex. These two studied coastal plains represent densely populated and industrialized areas, in which the quantity and quality of the groundwater bodies are under constant threat. At first, the resistivity models of the two groundwater bodies were realized through the inversion of a dataset of Vertical Electrical Soundings (VES), constrained by stratigraphic well logs data and other geophysical data. The 3D resistivity models obtained by spatially interpolating 1D inverse VES models have allowed for an initial recognition of the distribution of groundwater, as well as a rough geological framework of the subsoil. Subsequently, these models were implemented by integrating results from active and passive seismic data to determine the seismic P and S wave velocities of the main lithotypes. Simultaneous acquisition and interpretation of seismic and electrical tomographies along identical profiles allowed to determine the specific values of seismic velocity, electrical resistivity and chargeability of the alluvial sediments, and to use these values to constrain the HVSR inversion. All this allowed us to recognize the areal extension and thickness of the various lithotypes in the two investigated areas and, finally, to define the depth and the morphology of the base of the groundwater bodies and the thickness of the filling deposits. Full article
(This article belongs to the Special Issue Application of Geophysical Methods for Hydrogeology)
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15 pages, 14695 KiB  
Article
Hydrodynamic Characterization of Carbonate Aquifers Using Atypical Pumping Tests without the Interruption of the Drinking Water Supply
by Sergio Rusi, Diego Di Curzio and Alessia Di Giovanni
Water 2024, 16(7), 1047; https://doi.org/10.3390/w16071047 - 5 Apr 2024
Viewed by 739
Abstract
The Gran Sasso carbonate aquifer is the largest and most productive in the Apennines. Its hydrogeological structure has been studied since the middle of the last century for the springs’ characterization for drinking purposes and for a motorway tunnel. Meanwhile, its hydrodynamic parametrization [...] Read more.
The Gran Sasso carbonate aquifer is the largest and most productive in the Apennines. Its hydrogeological structure has been studied since the middle of the last century for the springs’ characterization for drinking purposes and for a motorway tunnel. Meanwhile, its hydrodynamic parametrization is less developed and has been limited to monitoring the discharge and chemical and isotopic parameters. Secondary porosity characterizes the aquifer, and an underlying impermeable marly complex represents the basal aquiclude. It might appear inappropriate to characterize the hydraulic properties via pumping tests, as their reliability has been proven in homogeneous and isotropic media. However, the high extent of the aquifer, the wells’ location, the scarcity of information available and the lack of alternatives has forced the estimation of hydrodynamic parameters as in porous aquifers and the experimental testing of the aquifer, especially in maximum pumping conditions, for a possible exploitation increase. Since aquifer testing was performed during the normal well field’s activities, it was not possible to perform typical tests. Therefore, the step-drawdown test was conducted by turning on an increasing number of wells over time and keeping the observation points fixed. As results, a mean hydraulic conductivity of 5 × 10−3 m/s and a mean transmissivity of 0.3 m2/s were established without interrupting the water supply; meanwhile, the influence radius and flow directions were also estimated. Full article
(This article belongs to the Section Hydrogeology)
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21 pages, 4563 KiB  
Article
Effect of Simulated Eutrophication of Peatlands on the Microbiome of Utricularia vulgaris L.
by Aleksandra Bartkowska and Tomasz Mieczan
Water 2024, 16(7), 1046; https://doi.org/10.3390/w16071046 - 5 Apr 2024
Viewed by 589
Abstract
Global climate change and increasing human impact are the main factors intensifying eutrophication of peatland ecosystems. Due to the high sensitivity of certain groups of microorganisms, they can serve as indicators of the degree of eutrophication and thereby provide much important information for [...] Read more.
Global climate change and increasing human impact are the main factors intensifying eutrophication of peatland ecosystems. Due to the high sensitivity of certain groups of microorganisms, they can serve as indicators of the degree of eutrophication and thereby provide much important information for assessment of the state of peatland ecosystems. However, there is still little knowledge of how changes in the fertility of the environment can affect the microbiome of carnivorous plants in these ecosystems. This study was conducted to verify the following hypotheses: (1) the microbiome of carnivorous plant traps reflects the trophic status of the habitat; (2) an increase in the concentration of biogenic compounds causes a greater increase in the size of microbial communities in the aquatic environment than in the traps. An experiment was carried out in laboratory conditions to determine the effect of simulated eutrophication on the microbiome of Utricularia vulgaris L. An experimental increase in habitat fertility caused an increase in the abundance of bacteria, flagellates, testate amoebae, ciliates, and rotifers, while a decrease in abundance was observed for crustaceans. The increase in the concentration of biogenic compounds also modified the taxonomic composition of communities of microorganisms and small metazoa as well as the strength of trophic relationships; as the trophic level increased, the relationships between bacteria and heterotrophic flagellates; bacteria and testate amoebae; and bacteria and ciliates became stronger. Full article
(This article belongs to the Section Hydrology)
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16 pages, 5779 KiB  
Article
Changes in Drought Characteristics in the Yellow River Basin during the Carbon-Neutral Period under Low-Emission Scenarios
by Xunyu Li, Yang Jiao and Jieyu Liu
Water 2024, 16(7), 1045; https://doi.org/10.3390/w16071045 - 5 Apr 2024
Viewed by 568
Abstract
Droughts have a severe impact on the environment and social economy, and predicting their future changes is challenging due to significant uncertainties in climate change and human activities. Many countries have pledged to achieve carbon neutrality to limit global warming; however, few studies [...] Read more.
Droughts have a severe impact on the environment and social economy, and predicting their future changes is challenging due to significant uncertainties in climate change and human activities. Many countries have pledged to achieve carbon neutrality to limit global warming; however, few studies have focused on drought changes during the carbon-neutral period. Here, we analyzed the variations in drought characteristics across the Yellow River Basin (YRB) during the carbon-neutral period under two low-emission scenarios from 7 CMIP6 model outputs. The results show that the temperature and precipitation will increase significantly during the 2015–2100 period under both SSP1-1.9 and SSP1-2.6 scenarios. Compared to the historical period (1979–2014), the hydrological drought frequency is projected to decrease by 15.5% (13.0–18.1%), while drought severity is expected to increase by 14.4% (13.2–15.7%) during the carbon-neutral period. Meteorological droughts exhibit a similar changing trend, although the results vary between different regions. In general, more severe hydrological droughts may occur in the southern YRB in the carbon-neutral period under low-emission scenarios. This study has implications for future drought mitigation within the Yellow River Basin. Full article
(This article belongs to the Special Issue Drought Occurrences, Characteristics, Impacts and Mitigations)
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18 pages, 2438 KiB  
Article
Runoff Simulation of the Upstream Watershed of the Feiling Hydrological Station in the Qinhe River Based on the SWAT Model
by Kun Wang, Dafen Yue and Huadong Zhang
Water 2024, 16(7), 1044; https://doi.org/10.3390/w16071044 - 4 Apr 2024
Viewed by 807
Abstract
This study examined the impacts of climate change and human activities on runoff within the Feiling Hydrological Station watershed in the Qinhe River basin, utilizing the SWAT (Soil and Water Assessment Tool) model. Several climate change and extreme land-use scenarios were evaluated for [...] Read more.
This study examined the impacts of climate change and human activities on runoff within the Feiling Hydrological Station watershed in the Qinhe River basin, utilizing the SWAT (Soil and Water Assessment Tool) model. Several climate change and extreme land-use scenarios were evaluated for their effects on runoff. Results demonstrated the SWAT model’s suitability for runoff simulation in the watershed, revealing a negative correlation between runoff and temperature changes, and a positive correlation with precipitation changes. Significantly, runoff responses to precipitation variations of ±10% and ±20% were more marked than those to temperature changes of ±1 °C and ±2 °C. In scenarios of extreme woodland and fallow land, runoff decreased, whereas in scenarios of extreme cropland and grassland, it increased, particularly in the extreme farmland scenario. The study’s findings are important for the sensible management of soil and water resources and the enhancement of the natural environment in the studied area. Full article
(This article belongs to the Topic Hydrology and Water Resources Management)
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15 pages, 1745 KiB  
Review
The Impact of Climate Change on the Failure of Water Supply Infrastructure: A Bibliometric Analysis of the Current State of Knowledge
by Jakub Żywiec, Dawid Szpak, Katarzyna Wartalska and Martyna Grzegorzek
Water 2024, 16(7), 1043; https://doi.org/10.3390/w16071043 - 4 Apr 2024
Viewed by 981
Abstract
With ongoing climate change, new threats appear to the operation of water supply systems (WSSs), which are related to the amount of available drinking water resources, its quality, the operation of existing water supply infrastructure and changes in consumer behavior. The paper presents [...] Read more.
With ongoing climate change, new threats appear to the operation of water supply systems (WSSs), which are related to the amount of available drinking water resources, its quality, the operation of existing water supply infrastructure and changes in consumer behavior. The paper presents a bibliometric analysis of the state of knowledge on the impact of climate change on the failure of water supply infrastructure. The bibliometric analysis was performed based on the VOSviewer program. The results of the analysis indicate current research trends in this area around the world and allow the identification of strengths and weaknesses. Most research concerns the identification of factors related to the impact of climate on the failure rate of water distribution systems. A popular research topic was also the prediction of water supply network failures, taking into account the impact of climatic factors. The main research gap is determining the impact of climate change on water quality. The acquired knowledge can be used by water companies, policy-makers and other researchers to plan adaptation strategies to climate change, which pose new challenges for the operation of water supply systems. The conducted bibliometric analysis also allowed for identifying research gaps. Full article
(This article belongs to the Section Urban Water Management)
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14 pages, 2589 KiB  
Article
Applying Recurrent Neural Networks and Blocked Cross-Validation to Model Conventional Drinking Water Treatment Processes
by Aleksandar Jakovljevic, Laurent Charlin and Benoit Barbeau
Water 2024, 16(7), 1042; https://doi.org/10.3390/w16071042 - 4 Apr 2024
Viewed by 979
Abstract
The jar test is the current standard method for predicting the performance of a conventional drinking water treatment (DWT) process and optimizing the coagulant dose. This test is time-consuming and requires human intervention, meaning it is infeasible for making continuous process predictions. As [...] Read more.
The jar test is the current standard method for predicting the performance of a conventional drinking water treatment (DWT) process and optimizing the coagulant dose. This test is time-consuming and requires human intervention, meaning it is infeasible for making continuous process predictions. As a potential alternative, we developed a machine learning (ML) model from historical DWT plant data that can operate continuously using real-time sensor data without human intervention for predicting clarified water turbidity 15 min in advance. We evaluated three types of models: multilayer perceptron (MLP), the long short-term memory (LSTM) recurrent neural network (RNN), and the gated recurrent unit (GRU) RNN. We also employed two training methodologies: the commonly used holdout method and the theoretically correct blocked cross-validation (BCV) method. We found that the RNN with GRU was the best model type overall and achieved a mean absolute error on an independent production set of as low as 0.044 NTU. We further found that models trained using BCV typically achieve errors equal to or lower than their counterparts trained using holdout. These results suggest that RNNs trained using BCV are superior for the development of ML models for DWT processes compared to those reported in earlier literature. Full article
(This article belongs to the Special Issue Using Artificial Intelligence in Water Research)
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