Water

5 pages, 171 KiB

Open AccessEditorial

Editorial to Efficient Catalytic and Microbial Treatment of Water Pollutants

by Ivar Zekker

Water 2022, 14(6), 995; https://doi.org/10.3390/w14060995 - 21 Mar 2022

Cited by 1 | Viewed by 1950 | Correction

Several industries produce products and release waste compounds that can be very carcinogenic, and furthermore, can cause trouble for water organisms, such as algae and plants which rely on photosynthesis [...] Full article

(This article belongs to the Special Issue Efficient Catalytic and Microbial Treatment of Water Pollutants)

16 pages, 1599 KiB

Open AccessFeature PaperArticle

Identification of Rainfall Thresholds Likely to Trigger Flood Damages across a Mediterranean Region, Based on Insurance Data and Rainfall Observations

by Katerina Papagiannaki, Vassiliki Kotroni, Kostas Lagouvardos, Antonis Bezes, Vasileios Vafeiadis, Ioanna Messini, Efstathios Kroustallis and Ioannis Totos

Water 2022, 14(6), 994; https://doi.org/10.3390/w14060994 - 21 Mar 2022

Cited by 2 | Viewed by 3919

Abstract

Flood-producing rainfall amounts have a significant cumulative economic impact. Despite the advance in flood risk mitigation measures, the cost of rehabilitation and compensation of citizens by the state and insurance companies is increasing worldwide. A continuing challenge is the flood risk assessment based [...] Read more.

Flood-producing rainfall amounts have a significant cumulative economic impact. Despite the advance in flood risk mitigation measures, the cost of rehabilitation and compensation of citizens by the state and insurance companies is increasing worldwide. A continuing challenge is the flood risk assessment based on reliable hazard and impact measures. The present study addresses this challenge by identifying rainfall thresholds likely to trigger economic losses due to flood damages to properties across the Athens Metropolitan Area of Greece. The analysis uses eight-year rainfall observations from 66 meteorological stations and high spatial resolution insurance claims on the postal code segmentation. Threshold selection techniques were applied based on the ROC curves widely used to assess the performance of binary response models. The model evaluates the probability of flood damages in terms of insurance claims in this case. Thresholds of 24-h rainfall were identified at the municipal level, as municipalities are the first administration level where decision making to address the local risks for the citizens is needed. The rainfall thresholds were further classified to estimate and map the local risk of flood damages. Practical implications regarding the applicability of the detected thresholds in early-warning systems are also discussed. Full article

(This article belongs to the Special Issue Innovative Approaches Applied to Flood Risk Management in Urban Areas)

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13 pages, 2147 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Prediction of Flow Based on a CNN-LSTM Combined Deep Learning Approach

by Peifeng Li, Jin Zhang and Peter Krebs

Water 2022, 14(6), 993; https://doi.org/10.3390/w14060993 - 21 Mar 2022

Cited by 64 | Viewed by 8124

Abstract

Although machine learning (ML) techniques are increasingly used in rainfall-runoff models, most of them are based on one-dimensional datasets. In this study, a rainfall-runoff model with deep learning algorithms (CNN-LSTM) was proposed to compute runoff in the watershed based on two-dimensional rainfall radar [...] Read more.

Although machine learning (ML) techniques are increasingly used in rainfall-runoff models, most of them are based on one-dimensional datasets. In this study, a rainfall-runoff model with deep learning algorithms (CNN-LSTM) was proposed to compute runoff in the watershed based on two-dimensional rainfall radar maps directly. The model explored a convolutional neural network (CNN) to process two-dimensional rainfall maps and long short-term memory (LSTM) to process one-dimensional output data from the CNN and the upstream runoff in order to calculate the flow of the downstream runoff. In addition, the Elbe River basin in Sachsen, Germany, was selected as the study area, and the high-water periods of 2006, 2011, and 2013, and the low-water periods of 2015 and 2018 were used as the study periods. Via the fivefold validation, we found that the Nash–Sutcliffe efficiency (NSE) and Kling–Gupta efficiency (KGE) fluctuated from 0.46 to 0.97 and from 0.47 to 0.92 for the high-water period, where the optimal fold achieved 0.97 and 0.92, respectively. For the low-water period, the NSE and KGE ranged from 0.63 to 0.86 and from 0.68 to 0.93, where the optimal fold achieved 0.86 and 0.93, respectively. Our results demonstrate that CNN-LSTM would be useful for estimating water availability and flood alerts for river basin management. Full article

(This article belongs to the Special Issue Optimization and Prediction of Water Quality Model Based on Artificial Intelligence)

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20 pages, 2624 KiB

Open AccessArticle

Flood Risk Perception and Its Attributes among Rural Households under Developing Country Conditions: The Case of Pakistan

by Ashfaq Ahmad Shah, Chen Ajiang, Nasir Abbas Khan, Bader Alhafi Alotaibi and Muhammad Atiq Ur Rehman Tariq

Water 2022, 14(6), 992; https://doi.org/10.3390/w14060992 - 21 Mar 2022

Cited by 31 | Viewed by 6267

Abstract

Managing and communicating flood risks necessitates a strong understanding of how people perceive risk. It has become critical to examine risk perception to implement effective disaster risk management (DRM) measures. Socioeconomic determinants have an impact on risk perception, which in turn affects future [...] Read more.

Managing and communicating flood risks necessitates a strong understanding of how people perceive risk. It has become critical to examine risk perception to implement effective disaster risk management (DRM) measures. Socioeconomic determinants have an impact on risk perception, which in turn affects future adaptive capacity and disaster preparedness. First and foremost, this research attempts to determine how Pakistani people in rural areas perceive flood risk, and second, to examine the factors that can influence rural residents’ perceptions of flood risk. The data for this study were collected through face-to-face interviews with 600 respondents (household heads) from Charsadda and Nowshera districts that were severely affected by the 2010 flood. A flood risk perception index was developed (using a risk matrix) using relevant attributes on a Likert scale and classified into two categories: high and low perceived risk. Furthermore, a binary regression model was used to examine the influence of socioeconomic and institutional factors on rural households’ risk perception. Flood risk was perceived by 67 percent of the total sampled participants in the study regions. The results of binary logistic regression demonstrate that flood risk perception is strongly linked to socioeconomic variables such as age, education, house ownership, family size, past flood experience, and distance from the nearest river source, as well as institutional factors such as access to credit and extreme weather forecast information. The findings of the current study additionally revealed that flood risk perception varied among household heads based on education (1–10 years perceived high flood risk (51.47%)), age (age greater than 40 years perceived high flood risk (52.83%)), and monthly income levels (lower monthly income group perceived high flood risk (73.02%)). The findings of this study shed light on rural households’ perception of flood risk and the factors that shape such perceptions. These findings can assist provincial and local disaster management authorities in better understanding flood risk and adopting local actions that could be used to respond to flood and other climate-related disasters. Full article

(This article belongs to the Special Issue Flood Risk Management and Resilience)

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15 pages, 471 KiB

Open AccessArticle

Study on the Decoupling Relationship and Rebound Effect between Agricultural Economic Growth and Water Footprint: A Case of Yangling Agricultural Demonstration Zone, China

by Jianwen Shi

Water 2022, 14(6), 991; https://doi.org/10.3390/w14060991 - 21 Mar 2022

Cited by 6 | Viewed by 2472

Abstract

The coordinated development of the economy, water resources, and environment is key to the concept of sustainable development. In this study, in respect to the water footprint, it calculated the water resource input and sewage dilution for the Yangling Agricultural Demonstration Area during [...] Read more.

The coordinated development of the economy, water resources, and environment is key to the concept of sustainable development. In this study, in respect to the water footprint, it calculated the water resource input and sewage dilution for the Yangling Agricultural Demonstration Area during the agricultural economic growth period from 1999 to 2019. This study also established the Tapio decoupling analysis model on this basis to study the decoupling relationship between economic growth and the water resource environment, as well as its evolution law. A residual free-complete decomposition model was introduced to analyze the influence of the water resource input and sewage dilution on the agricultural economic growth in the Yangling Demonstration Area and its transmission mechanism. The results showed the following: (1) the economic growth and the blue and green water footprints of the Yangling Demonstration Area were decoupled from one another from 1999 to 2019, and the degree of decoupling between economic growth and the grey-water footprint was poor, indicating that economic growth had a more obvious promotion effect on the reduction of water resource consumption, and the pressure on the water environment was increased year by year; (2) the main factor affecting the reduction of water resource consumption in the Yangling Demonstration Area was the effect of technology, and this was greater than the effect of water resource consumption increments resulting from the expansion of the economic scale; (3) the progress of environmental governance technology was the main reason for the decrease in the grey-water footprint in the Yangling Demonstration Area. To improve the quality of our economic development, the pattern of economic development should be transformed to regulate economic growth and expand the scale, reducing water consumption, improving pollutant emission control technology, and making full use of water resources to provide evidence for a reasonable water resource management policy. Full article

(This article belongs to the Section Water Use and Scarcity)

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18 pages, 3385 KiB

Open AccessArticle

Analysis of Water Balance Changes and Parameterization Reflecting Soil Characteristics in a Hydrological Simulation Program—FORTRAN Model

by Soohong Kim, Jonggun Kim, Hyeongsik Kang, Won Seok Jang and Kyoung Jae Lim

Water 2022, 14(6), 990; https://doi.org/10.3390/w14060990 - 21 Mar 2022

Cited by 7 | Viewed by 3755

Abstract

Efficient water resource management requires accurate analyses of hydrological components and water balance. The Hydrological Simulation Program—FORTRAN (HSPF) model serves this purpose at the watershed scale. It has limited accuracy in calculating runoff and infiltration because the model simulates hydrological processes using one [...] Read more.

Efficient water resource management requires accurate analyses of hydrological components and water balance. The Hydrological Simulation Program—FORTRAN (HSPF) model serves this purpose at the watershed scale. It has limited accuracy in calculating runoff and infiltration because the model simulates hydrological processes using one representative parameter for each land use in the watershed. Accuracy requires field-scale analysis of hydrological components. We calculated the lower zone storage nominal parameter, which markedly affects runoff in HSPF, from effective moisture content and depth of each soil layer. Analysis of hydrological components suggested re-calculating the parameters reflecting soil characteristics. We investigated two scenarios through simulations: Scenario 1 used the existing method. Scenario 2 used parameters that reflected soil properties. Total flows for each sub-catchment were identical, but proportions of direct and intermediate runoff were larger in Scenario 1. Ratios of baseflow, evapotranspiration, and infiltration were larger in Scenario 2, reflecting soil characteristics. Comparing the baseflow ratio to total flow, Scenario 2 values were similar to observed values. Comparisons of R² and Nash–Sutcliffe Efficiency (NSE) at the end of the watershed were well matched (R² and NSE are higher than 0.9) in both scenarios, but proportions of each hydrological component differed. It is important to consider soil characteristics when applying water quantity and quality analyses in an HSPF simulation. Full article

(This article belongs to the Special Issue Climate, Water, and Soil)

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22 pages, 3396 KiB

Open AccessFeature PaperArticle

Evaluation of Land-Use Changes as a Result of Underground Coal Mining—A Case Study on the Upper Nitra Basin, West Slovakia

by Matej Mojses, František Petrovič and Gabriel Bugár

Water 2022, 14(6), 989; https://doi.org/10.3390/w14060989 - 21 Mar 2022

Cited by 6 | Viewed by 3095

Abstract

Mining activity has one of the most fundamental influences on the landscape (in terms of both aesthetics and use). Its activity and manifestations, even when mining takes place underground, have visual manifestations on the surface. The impact of subsurface mining has a synergistic [...] Read more.

Mining activity has one of the most fundamental influences on the landscape (in terms of both aesthetics and use). Its activity and manifestations, even when mining takes place underground, have visual manifestations on the surface. The impact of subsurface mining has a synergistic effect on the elements of the landscape structure. This manifestation is continuous in the context of mining intensity. Using the Earth remote sensing method, we identified several fundamental changes. The most significant of these was the creation of wetlands and the modification of watercourse lines. In the area in which there was no permanent water sources, several water areas with a total area of more than 30 ha were created. We also found that the length of watercourses has halved, the area of grassland has doubled, and urban area has decreased. It was the creation of water areas that supported not only better ecological stability of the landscape, but also the growth of biodiversity. Wetlands can be a dynamic element of future development. Understanding the development of land-cover changes is necessary for the purpose of planning nature and landscape conservation, as well as to identify areas of conflict with economic use. Full article

(This article belongs to the Special Issue Water Energy Use of Rivers in the Historical Context and Water Return to the (Urban/Agricultural) Landscape)

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15 pages, 9424 KiB

Open AccessArticle

Differences in Spatiotemporal Variability of Potential and Reference Crop Evapotranspirations

by Keyu Xiang, Xuan Zhang, Xiaofeng Peng, Ning Yao, Asim Biswas, Deli Liu, Yufeng Zou, Bakhtiyor Pulatov, Yi Li and Fenggui Liu

Water 2022, 14(6), 988; https://doi.org/10.3390/w14060988 - 21 Mar 2022

Cited by 1 | Viewed by 2524

Abstract

Potential evapotranspiration (ET_p) and reference crop evapotranspiration (ET_o) are two key parameters in hydrology, meteorology, and agronomy. ET_p and ET_o are related to each other but have different meanings and applications. In this study, the [...] Read more.

Potential evapotranspiration (ET_p) and reference crop evapotranspiration (ET_o) are two key parameters in hydrology, meteorology, and agronomy. ET_p and ET_o are related to each other but have different meanings and applications. In this study, the ET_p and ET_o were distinguished and calculated with the Penman and FAO56 PM equations using the weather data of 551 stations in China from 1961 to 2018. The differences in their spatiotemporal variations were examined with an MMK test, an R/S test, and wavelet analysis. The monthly ET_p and ET_o were close but the ET_p was always larger than the ET_o, with values ranging from 1 to 356 mm and 2 to 323 mm, respectively. Their differences varied in different months and sub-regions. The maximum monthly difference transferred from south to north and then back to the south in a yearly cycle, showing spatiotemporal heterogeneity. The annual values of the ET_p and ET_o were also close, but the ET_p was significantly higher than the ET_o. The increasing future trends of ET_p but decreasing trends of ET_o were tested at most sites in China. Although the primary periods were almost the same, their spatial distribution was slightly different. In conclusion, ET_p is different from ET_o and they should be applied carefully. This study performs a thorough comparison and reveals the underlying basis of and discrepancy between ET_p and ET_o. Full article

(This article belongs to the Section Hydrology)

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21 pages, 3513 KiB

Open AccessArticle

Removal of Organoselenium from Aqueous Solution by Nanoscale Zerovalent Iron Supported on Granular Activated Carbon

by Stanley Onyinye Okonji, Gopal Achari and David Pernitsky

Water 2022, 14(6), 987; https://doi.org/10.3390/w14060987 - 21 Mar 2022

Cited by 6 | Viewed by 2316

Abstract

Nanoscale zerovalent iron particles (nZVI) immobilized on coconut shell-based granular activated carbon (GAC) were studied to remove organoselenium from wastewater. A chemical reduction technique that involves the application of sodium borohydride was adopted for the adsorbent preparation. The texture, morphology and chemical composition [...] Read more.

Nanoscale zerovalent iron particles (nZVI) immobilized on coconut shell-based granular activated carbon (GAC) were studied to remove organoselenium from wastewater. A chemical reduction technique that involves the application of sodium borohydride was adopted for the adsorbent preparation. The texture, morphology and chemical composition of the synthesized adsorbents were analyzed with a scanning electron microscope (SEM), nitrogen adsorption–desorption isotherms and X-ray diffraction (XRD). Batch experiment with various pHs and contact times were conducted to evaluate nZVI/GAC adsorption performance. The results showed that nZVI/GAC has a strong affinity to adsorb selenomethionine (SeMet) and selenocysteine (SeCys) from wastewaters. The maximum removal efficiency for the composite (nZVI/GAC) was 99.9% for SeCys and 78.2% for SeMet removal, which was significantly higher than that of nZVI (SeCy, 59.2%; SeMet, 10.8%). The adsorption kinetics were studied by pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models. Amongst the two, PSO seemed to have a better fit (SeCy, R² > 0.998; SeMet, R² > 0.999). The adsorption process was investigated using Langmuir and Freundlich isotherm models. Electrostatic attraction played a significant role in the removal of organoselenium by nZVI/GAC adsorption. Overall, the results indicated that GAC-supported nZVI can be considered a promising and efficient technology for removing organoselenium from wastewater. Full article

(This article belongs to the Special Issue Advanced Oxidative Methods in Wastewater Treatment)

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17 pages, 3114 KiB

Open AccessArticle

Why the Effect of CO₂ on Potential Evapotranspiration Estimation Should Be Considered in Future Climate

by Jian Zhou, Shan Jiang, Buda Su, Jinlong Huang, Yanjun Wang, Mingjin Zhan, Cheng Jing and Tong Jiang

Water 2022, 14(6), 986; https://doi.org/10.3390/w14060986 - 21 Mar 2022

Cited by 8 | Viewed by 2687

Abstract

Potential evapotranspiration (PET) is an important factor that needs to be considered in regional water management and allocation; thus, the reasonable estimation of PET is an important topic in hydrometeorology and other related fields. There is evidence that increased CO₂ concentration alters [...] Read more.

Potential evapotranspiration (PET) is an important factor that needs to be considered in regional water management and allocation; thus, the reasonable estimation of PET is an important topic in hydrometeorology and other related fields. There is evidence that increased CO₂ concentration alters the physiological properties of vegetation and thus affects PET. In this study, changes in PET with and without the CO₂ effect over China is investigated using seven CMIP6-GCMs outputs under seven shared socioeconomic pathways (SSPs) based scenarios (SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP4-3.4, SSP4-6.0, and SSP5-8.5), as well as the contribution rate of CO₂ on PET in different climatic regions. Changes in estimated PET based on modified Penman–Monteith (PM) method that considers the CO₂ effect is compared with the traditional PM method to examine how PET quantity varies (differences) between these two approaches. The results show that the PET values estimated by the two methods explored opposite trends in 1961–2014 over entire China; it decreases with consideration of CO₂ but increases without consideration of CO₂. In the future, overall PET is projected to increase under all scenarios during 2015–2100 for China and its three sub-regions. PET generally tends to grow slower when CO₂ is taken into account (modified PM approach), than when it is not (traditional PM method). In terms of differences in the estimated PET by the two methods, the difference between the two adopted methods increased in China and its sub-regions for the 1961–2014 period. In the future, the difference in estimated PET is anticipated to continuously increase under SSP3-7.0 and SSP5-8.5. Spatially, a much greater extent of difference is found in the arid region. Across the arid region, the PET difference is projected to be the highest at 138% in the mid-term (2041–2060) with respect to the 1995–2014 period, whereas it tends to increase slower in the long-term period (2081–2100). Importantly, CO₂ is found to be the most dominant factor (−154.2% contribution) to have a great effect on PET changes across the arid region. Our findings suggest that ignorance of CO₂ concentration in PET estimation will result in significant overestimation of PET in the arid region. However, consideration of CO₂ in PET estimation will be beneficial for formulating strategies on future water resource management and sustainable development at the local scale. Full article

(This article belongs to the Section Hydrology)

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13 pages, 5355 KiB

Open AccessArticle

Groundwater Recharge Modeling under Water Diversion Engineering: A Case Study in Beijing

by Mingyan Zhao, Xiangbo Meng, Boxin Wang, Dasheng Zhang, Yafeng Zhao and Ruyi Li

Water 2022, 14(6), 985; https://doi.org/10.3390/w14060985 - 21 Mar 2022

Cited by 6 | Viewed by 3669

Abstract

The influence of surface water resource exploitation and utilization projects on groundwater has been widely studied. Surface water diversion projects lead to a reduction in river discharge, which changes the recharge of groundwater systems. In this study, the numerical simulation method is used [...] Read more.

The influence of surface water resource exploitation and utilization projects on groundwater has been widely studied. Surface water diversion projects lead to a reduction in river discharge, which changes the recharge of groundwater systems. In this study, the numerical simulation method is used to predict the variation in groundwater level under different diversion scale scenarios. The Zhangfang water diversion project in Beijing, China, was chosen for the case study. The downstream plain area of the Zhangfang water diversion project is modeled by MODFLOW to predict the influence of reducing water diversion on the dynamic change in the groundwater level in the downstream plain area. The model results show that the difference in groundwater recharge and discharge on the downstream plain of Zhangfang is 9,991,900 m³/a, which is in a negative water balance state, and the groundwater level continues to decrease. Reducing the amount of water diverted by the Zhangfang water diversion project to replenish groundwater is beneficial to the rise of the groundwater level in the downstream plain area. The results indicate that the groundwater flow model in the downstream plain area of Zhangfang performed well in the influence assessment of surface water resource exploitation and utilization projects on groundwater. This study also provides a good example of how to coordinate the relationship between surface water resources and groundwater resources. Full article

(This article belongs to the Special Issue River Ecological Restoration and Groundwater Artificial Recharge)

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21 pages, 6474 KiB

Open AccessArticle

Physical Modeling for Large-Scale Landslide with Chair-Shaped Bedrock Surfaces under Precipitation and Reservoir Water Fluctuation Conditions

by Shangtao Pan, Wei Gao and Ruilin Hu

Water 2022, 14(6), 984; https://doi.org/10.3390/w14060984 - 21 Mar 2022

Cited by 5 | Viewed by 2712

Abstract

The deformation and failure mechanisms of historical landslides, characterized with different types of bedrock surface shapes which are known to have been induced by rainfall and reservoir water fluctuations, is an important issue currently being addressed by many researchers. The Zhaoshuling Landslide of [...] Read more.

The deformation and failure mechanisms of historical landslides, characterized with different types of bedrock surface shapes which are known to have been induced by rainfall and reservoir water fluctuations, is an important issue currently being addressed by many researchers. The Zhaoshuling Landslide of the Three Gorges Reservoir Region, which was characterized with a chair-shaped bedrock surface under rainfall and reservoir water fluctuation conditions, was selected as an example in this study’s physical modeling process. The results of different parameters, including the displacements, pore water pressure, and total soil pressure during the landslide event, revealed that the Zhaoshuling Landslide with a chair-shaped bedrock surface had been extremely sensitive to heavy rainfall coupled with the rapid lowering of the water levels. Then, based on the data analysis results of the monitoring of the rainfall and groundwater levels, as well as the reservoir water levels, a conceptual model was put forward to explain the failure mechanisms. It was believed that the chair-shaped bedrock at the toe of the slope had been subjected to a localized zone of high transient pore water pressure, which had significantly adverse effects on the mechanisms of the slope stability. Full article

(This article belongs to the Special Issue Rainfall-Induced Geological Disasters)

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18 pages, 2821 KiB

Open AccessArticle

The Impacts of the Freezing–Thawing Process on Benthic Macroinvertebrate Communities in Riffles and Pools: A Case Study of China’s Glacier-Fed Stream

by Yilin Tian, Yuwei Liu, Yingzhi Gao, Dong Cui, Wei Zhang, Ziwei Jiao, Fulong Yao, Zhenxing Zhang and Haijun Yang

Water 2022, 14(6), 983; https://doi.org/10.3390/w14060983 - 21 Mar 2022

Cited by 1 | Viewed by 2844

Abstract

Glacier-fed streams are one of the environments most sensitive to global climate change. However, the effects of the freezing–thawing process on benthic macroinvertebrate communities in different habitats of glacier-fed streams are unclear. In this paper, we investigated benthic macroinvertebrates in riffles and pools [...] Read more.

Glacier-fed streams are one of the environments most sensitive to global climate change. However, the effects of the freezing–thawing process on benthic macroinvertebrate communities in different habitats of glacier-fed streams are unclear. In this paper, we investigated benthic macroinvertebrates in riffles and pools of a glacier-fed stream in Xinjiang, China, during the pre-freezing period (November, 2018), freezing period (January 2019), and thawing period (April, 2019). Our results showed that the freezing–thawing process resulted in a decline in benthic macroinvertebrate species richness and diversity, both of which were attributed to the effects of the freezing–thawing process on habitat stability, water quality, and cycling of the stream ecosystems. During the whole freezing–thawing process, the indicator taxa of riffles were Rhithrogena sp. and Baetis sp., while the only indicator taxon of pools was Chironomus sp. The species richness, Margalef diversity, and EPT richness (Ephemeroptera, Plecoptera, and Trichoptera) of benthic macroinvertebrates in riffles were higher than those in pools, due to the higher habitat heterogeneity in the riffles. However, the density in riffles was significantly lower than that in pools during the freezing period (p < 0.05). Additionally, pools were dominated by taxa with higher resilience and resistance traits, such as “bi- or multi-voltine”, “abundant occurrence in drift”, and “small size at maturity”. This result indicated that pools provide a temporary refuge for benthic macroinvertebrates in the extreme environment of glacier-fed streams. The freezing–thawing process plays an essential role in the formation of the structure and function of the stream ecosystem. Our results can help us to further understand the winter ecological process of headwater streams, and provide a reference for stream biodiversity conservation in cold regions. Full article

(This article belongs to the Section Biodiversity and Functionality of Aquatic Ecosystems)

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15 pages, 2832 KiB

Open AccessEditor’s ChoiceArticle

Sunflower Photosynthetic Characteristics, Nitrogen Uptake, and Nitrogen Use Efficiency under Different Soil Salinity and Nitrogen Applications

by Tao Ma, Kaiwen Chen, Pingru He, Yan Dai, Yiqun Yin, Suhan Peng, Jihui Ding, Shuang’en Yu and Jiesheng Huang

Water 2022, 14(6), 982; https://doi.org/10.3390/w14060982 - 20 Mar 2022

Cited by 16 | Viewed by 4690

Abstract

Understanding salinity and fertilizer interaction is of great importance to improve crop production and fertilizer use efficiency in saline areas. To evaluate the interactive effects of different soil salinity levels and nitrogen (N) applications rates on the sunflower photosynthetic characteristics of N uptake [...] Read more.

Understanding salinity and fertilizer interaction is of great importance to improve crop production and fertilizer use efficiency in saline areas. To evaluate the interactive effects of different soil salinity levels and nitrogen (N) applications rates on the sunflower photosynthetic characteristics of N uptake and N use efficiency, a two-year field experiment was conducted in Hetao Irrigation District, China. The experiment consisted of three initial salinity (IS) levels expressed as the electrical conductivity of a saturated soil extract (EC_e) (S0: 1.72–2.61 dS/m; S1: 4.73–5.90 dS/m; S2: 6.85–9.04 dS/m) and four N rates (45, 90, 135, and 180 kg/ha), referred as N0–N3, respectively. The results indicated that the net photosynthetic rate (Pn) of sunflowers treated with S0 and S1 levels both had a significant decrease in the bud stage, and then reached their maximum at anthesis. However, during the crop cycle, the Pn at S2 level only had small fluctuations and still remained at a high level (>40 μmol CO₂/(m² s)) at the early mature stage. When increasing IS levels from S0 to S1, the plant N uptake (PNU) under the same N rates were only decreased by less than 10% at maturity, whereas the decline was expanded to 17.2–45.7% from S1 to S2. Additionally, though applying the N2 rate could not increase sunflower PNU at the S0 and S1 levels, its N use efficiency was better than those under N3. Meanwhile, at the S2 level, the application of the N0 rate produced a higher N productive efficiency (NPE) and N uptake efficiency (NUPE) than the other N rates. Therefore, our study proposed recommended rates of N fertilizer (S0 and S1: 135 kg/ha, S2: 45 kg/ha) for sunflowers under different saline conditions. Full article

(This article belongs to the Special Issue Efficient Use of Water and Soil Resources)

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14 pages, 2356 KiB

Open AccessArticle

Ballast Water Management Strategy to Reduce the Impact of Introductions by Utilizing an Empirical Risk Model

by Yung-Sheng Chen, Chao-Kai Kang and Ta-Kang Liu

Water 2022, 14(6), 981; https://doi.org/10.3390/w14060981 - 20 Mar 2022

Cited by 4 | Viewed by 4138

Abstract

The introduction of non-indigenous aquatic species (NIASs) was identified as one of the major threats to aquatic ecosystems. Shipping is one of the potential invasive pathways for the introduction of marine NIASs, mainly via ballast water, sediments, and ship fouling. In addition, The [...] Read more.

The introduction of non-indigenous aquatic species (NIASs) was identified as one of the major threats to aquatic ecosystems. Shipping is one of the potential invasive pathways for the introduction of marine NIASs, mainly via ballast water, sediments, and ship fouling. In addition, The International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM Convention) aims to mitigate the introduction risk of harmful aquatic organisms and pathogens (HAOPs) via ships’ ballast water and sediment. Some of these species can be very harmful and cause loss of biodiversity, adverse environmental consequences, and economic and social impacts. In this study, an empirical model based on the environmental similarity and the vessel characteristics was used to assess the risk associated with the ballast water, for the incoming vessels to the port of Kaohsiung and port of Riga. The priority for port state control (PSC) inspection was established and recommended for better ballast water management. Full article

(This article belongs to the Special Issue The Relationship between Ships and Marine Environment)

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20 pages, 6095 KiB

Open AccessArticle

Partitioning and Availability of Metals from Water Suspended Sediments: Potential Pollution Risk Assessment

by Magaly Cabral-Lares, Marusia Rentería-Villalobos, Aurora Mendieta-Mendoza, Ziury Ortíz-Caballero, Elena Montero-Cabrera and Ignacio Vioque

Water 2022, 14(6), 980; https://doi.org/10.3390/w14060980 - 20 Mar 2022

Cited by 2 | Viewed by 2684

Abstract

The water management initiatives in freshwater systems focus on water availability to preserve this resource for human uses and the health of aquatic ecosystems. This work presents an assessment of the potential pollution risk caused by the metal availability in suspended sediments. The [...] Read more.

The water management initiatives in freshwater systems focus on water availability to preserve this resource for human uses and the health of aquatic ecosystems. This work presents an assessment of the potential pollution risk caused by the metal availability in suspended sediments. The objective of this study was to determine the partitioning, association, and geochemical fractionation of metals in suspended sediments from a surface water body. Additionally, the environmental assessment for this reservoir was estimated using geoaccumulation, enrichment, and pollution indices of metals and the related potential risk by their elemental availability (RAC). Chemical, mineralogical, and morphological characterizations were obtained by inductively coupled plasma spectrometry, alpha spectroscopy, X-ray crystallography, and scanning electron microscopy. Clay, quartz, montmorillonite, and calcite were the main minerals of suspended sediments. Chemical fractionation was the parameter affecting the concentrations of metals in suspended sediments. The sediment composition is of natural origin; however, these finer particles can promote the scavenging of toxic metals. It contributes to obtaining moderate to high levels for enrichment/contamination indices. Although Ca, Mg, and U were the most accessible metals for aquatic biota, metals such as Sr, Mn, Li, Cu, and Ni in the exchangeable phase of suspended sediments are the potentially toxic elements in this aquatic ecosystem. Full article

(This article belongs to the Special Issue Geochemistry of Water and Sediment Ⅱ)

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15 pages, 2918 KiB

Open AccessArticle

How Do Specific Environmental Conditions in Canals Affect the Structure and Variability of the Zooplankton Community?

by Nikola Kolarova and Paweł Napiórkowski

Water 2022, 14(6), 979; https://doi.org/10.3390/w14060979 - 20 Mar 2022

Cited by 6 | Viewed by 3049

Abstract

The present study investigates the responses of zooplankton (including changes in their structure and diversity) to physicochemical and biological parameters in two artificial waterways. Water samples were collected monthly from the Bydgoszcz Canal, the Noteć Canal, and the Brda River during the growing [...] Read more.

The present study investigates the responses of zooplankton (including changes in their structure and diversity) to physicochemical and biological parameters in two artificial waterways. Water samples were collected monthly from the Bydgoszcz Canal, the Noteć Canal, and the Brda River during the growing season of April–October 2019. We analyzed how selected parameters (including water temperature, Secchi disk visibility, oxygen concentration, conductivity, and pH, as well as nitrate, phosphate, and chl-a concentrations) affected seasonal variations in zooplankton diversity (T) and density (N). In total, we recorded 98 species, and average zooplankton density was 320 ind/L. At all sites, the same zooplankton species were dominant: Keratella cochlearis among rotifers and the Cladocera Bosmina longirostris among crustaceans. Rotifers dominated qualitatively and quantitatively over crustaceans. Zooplankton density and biomass, as well as the number of zooplankton species, were higher in the Bydgoszcz Canal than in the Brda River or the Noteć Canal. This may be connected to the locks on the Bydgoszcz Canal slowing down water flow, thereby increasing macrophyte vegetation, which creates ecological niches supporting zooplankton development. Full article

(This article belongs to the Special Issue Functioning of Small Water Bodies)

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14 pages, 3944 KiB

Open AccessArticle

Co-Design for Enhancing Flood Resilience in Davao City, Philippines

by Mamoru Miyamoto, Daiki Kakinuma, Tomoki Ushiyama, Abdul Wahid Mohamed Rasmy, Masaki Yasukawa, Della Grace Bacaltos, Anthony C. Sales, Toshio Koike and Masaru Kitsuregawa

Water 2022, 14(6), 978; https://doi.org/10.3390/w14060978 - 20 Mar 2022

Cited by 3 | Viewed by 15261

Abstract

Enhancing flood resilience, including the development of social capacity and early warning systems, in addition to structural measures, is one of the key solutions to mitigating flood damage, which will be more intensified in the future due to climate change. This study was [...] Read more.

Enhancing flood resilience, including the development of social capacity and early warning systems, in addition to structural measures, is one of the key solutions to mitigating flood damage, which will be more intensified in the future due to climate change. This study was conducted to develop a comprehensive methodology for enhancing flood resilience by improving society-wide disaster literacy under the governance formed through the active participation of all levels of stakeholders in Davao City, Philippines. Specifically, the development of the Online Synthesis System for Sustainability and Resilience, which integrates different disciplines, and the fostering of Facilitators, whose role is to interlink the science community and society, were implemented in a co-designing manner by the collective governance body. The development of basin- and barangay-scale hydrological models realized real-time flood forecasting and climate change impact assessment to identify intensified flood risk under the future climate. Co-designed e-learning workshops were held to foster about thirty Facilitators and help them produce twenty-one risk communication plans and workshop designs for fourteen barangays considering geographic, demographic, economic, and social features that they can utilize for public dissemination related to climate change adaptation to the target audiences in society. This paper presents a practical method to enhance flood resilience, demonstrating that the synthesis of science-based knowledge and human resource development can fill the gaps between the science community and society. Full article

(This article belongs to the Special Issue Lowering Risk by Increasing Resilience: Selected Papers from 8th International Conference on Flood Management (ICFM 8))

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19 pages, 4553 KiB

Open AccessArticle

Appraisal of Environmental Health and Ecohydrology of Free-Flowing Aghanashini River, Karnataka, India

by T. V. Ramachandra, Vinay Shivamurthy, Asulabha K. Subramanian, Sincy Varghese, Bharath Setturu and Bharath H. Aithal

Water 2022, 14(6), 977; https://doi.org/10.3390/w14060977 - 20 Mar 2022

Cited by 4 | Viewed by 3968

Abstract

Rivers are vital freshwater resources that cater to the needs of society. The burgeoning population and the consequent land-use changes have altered the hydrologic regime with biophysical and chemical integrity changes. This necessitates understanding the land-use dynamics, flow dynamics, hydrologic regime, and water [...] Read more.

Rivers are vital freshwater resources that cater to the needs of society. The burgeoning population and the consequent land-use changes have altered the hydrologic regime with biophysical and chemical integrity changes. This necessitates understanding the land-use dynamics, flow dynamics, hydrologic regime, and water quality of riverine ecosystems. An assessment of the land-use dynamics in the Aghanashini River basin reveals a decline in vegetation cover from 86.06% (1973) to 50.78% (2018). The computation of eco-hydrological indices (EHI) highlights that the sub-watersheds with native vegetation had higher infiltration (and storage) than water loss due to evapotranspiration and meeting the societal demand. The computation of water quality index helped to assess the overall water quality across seasons. The study provides insights into hydrology linkages with the catchment landscape dynamics to the hydrologists and land-use managers. These insights would aid in the prudent management of river basins to address water stress issues through watershed treatment involving afforestation with native species, appropriate cropping, and soil conservation measures. Full article

(This article belongs to the Special Issue Effects of Vegetation on Rainfall)

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15 pages, 1973 KiB

Open AccessFeature PaperArticle

Application of Saccharomyces cerevisiae in the Biosorption of Co(II), Zn(II) and Cu(II) Ions from Aqueous Media

by Evgenia Savastru, Dumitru Bulgariu, Cătălin-Ioan Zamfir and Laura Bulgariu

Water 2022, 14(6), 976; https://doi.org/10.3390/w14060976 - 19 Mar 2022

Cited by 25 | Viewed by 3911

Abstract

Yeast biomass is considered a low-cost material that can be successfully used for the biosorption of metal ions from aqueous solution, due to its structural characteristics. This study evaluates the biosorptive performance of Saccharomyces cerevisiae in the biosorption of Co(II), Zn(II) and Cu(II) [...] Read more.

Yeast biomass is considered a low-cost material that can be successfully used for the biosorption of metal ions from aqueous solution, due to its structural characteristics. This study evaluates the biosorptive performance of Saccharomyces cerevisiae in the biosorption of Co(II), Zn(II) and Cu(II) ions from aqueous media in batch mono-component systems. The influence of solution pH, biosorbent dose, contact time, temperature and initial metal ions concentration was examined step by step, to obtain the optimal conditions for biosorption experiments. Maximum uptake efficiency for all metal ions on this biosorbent was obtained at: pH = 5.0, 4.0 g biosorbent/L, room temperature of 23 °C, and a contact time of 60 min, and these were considered optimal. The equilibrium results were analyzed using Langmuir, Freundlich and Dubinin–Radushkevich isotherm models, while for the modeling of the kinetics data, three models (pseudo-first order, pseudo-second order and intra-particle diffusion) were used. Dubinin–Radushkevich isotherm model and the pseudo-second order model showed the best fit with the experimental data obtained at biosorption of Co(II), Zn(II) and Cu(II) ions on Saccharomyces cerevisiae. Both maximum biosorption capacities and pseudo-second rate constants follow the order: Co(II) > Zn(II) > Cu(II), suggesting that the structural particularities of metal ions are important in the biosorption processes. Based on the obtained equilibrium and kinetic parameters, the biosorption mechanism is analyzed and the possible applications are emphasized. Full article

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

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13 pages, 2491 KiB

Open AccessArticle

Seawater with Added Monosodium Glutamate Residue (MSGR) Is a Promising Medium for the Cultivation of Two Commercial Marine Microalgae

by Siteng Yu, Ze Yu, Qingjie Hou and Haiyan Pei

Water 2022, 14(6), 975; https://doi.org/10.3390/w14060975 - 19 Mar 2022

Cited by 3 | Viewed by 2823

Abstract

Phaeodactylum tricornutum and Nannochloropsis oceanica, with their satisfactory performance in accumulating lipids and other high-value products, have been successfully used for commercial production in recent years. However, costly chemicals in culture media greatly increase the price of the resulting bioproducts. To control [...] Read more.

Phaeodactylum tricornutum and Nannochloropsis oceanica, with their satisfactory performance in accumulating lipids and other high-value products, have been successfully used for commercial production in recent years. However, costly chemicals in culture media greatly increase the price of the resulting bioproducts. To control the cultivation cost, this paper assessed the potential of seawater supplemented with monosodium glutamate residue wastewater at a ratio of 1/500 (S-MSGR) to serve as a growing medium for these two marine species. Compared with the standard chemical culture medium, Erdschreiber’s medium (EM), both the algal growth and metabolite accumulation of P. tricornutum and N. oceanica were greatly promoted in S-MSGR. The maximum biomass concentrations of P. tricornutum and N. oceanica reached 0.93 and 0.36 g/L, which were, respectively, 1.5 and 1.9 times higher than those in EM medium. For lipid accumulation, P. tricornutum exhibited an excellent lipid productivity of 22.9 mg/L/day in S-MSGR, a 64% increase compared to EM medium. Furthermore, the average yield coefficients indicated good performance of P. tricornutum and N. oceanica in transferring the nitrogen in S-MSGR to the biomass, at 74.8 and 174.8 mg/g of nitrogen. In addition, compared with EM, the costs of the medium for lipid production of P. tricornutum and N. oceanica cultured in S-MSGR were USD 2.3 and 5.8/(kg lipid), which saved 96.9% and 97.6%, respectively. Therefore, this paper demonstrates that S-MSGR is a suitable nutrient resource for P. tricornutum and N. oceanica, and it has a great potential to cut the cultivation cost during real commercial production. Full article

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

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13 pages, 1713 KiB

Open AccessReview

Plankton under Pressure: How Water Conditions Alter the Phytoplankton–Zooplankton Link in Coastal Lagoons

by Domenico D’Alelio, Luca Russo, Gabriele Del Gaizo and Luigi Caputi

Water 2022, 14(6), 974; https://doi.org/10.3390/w14060974 - 19 Mar 2022

Cited by 3 | Viewed by 4510

Abstract

Transitional waters (TWs), such as coastal lagoons, are bodies of surface water at the transition between saline and freshwater domains. These environments play a vital role in guaranteeing ecosystem services, including provision of food, protection against meteorological events, as anthropogenic carbon sinks, and [...] Read more.

Transitional waters (TWs), such as coastal lagoons, are bodies of surface water at the transition between saline and freshwater domains. These environments play a vital role in guaranteeing ecosystem services, including provision of food, protection against meteorological events, as anthropogenic carbon sinks, and in filtering of pollutants. Due to the escalating overpopulation characterising coastlines worldwide, transitional systems are over-exploited, degraded, and reduced in their macroscopic features. However, information on the impact of anthropogenic pressures on planktonic organisms in these systems is still scanty and fragmented. Herein, we summarise the literature, with a special focus on coastal lagoons undergoing anthropogenic pressure. Specifically, we report on the implications of human impacts on the ecological state of plankton, i.e., a fundamental ecological component of aquatic ecosystems. Literature information indicates that human forces may alter ecosystem structures and functions in coastal lagoons, as in other TWs such as estuaries, hampering the phytoplankton–zooplankton link, i.e., the main trophic process occurring in those communities, and which sustains aquatic productivity. Changes in the dominance and lifestyle of key planktonic players, plus the invasion of ‘alien’ species, and consequent regime shifts, are among the most common outcomes of human disturbance. Full article

(This article belongs to the Special Issue The Phytoplankton-Zooplankton Link under Anthropogenic Pressures)

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19 pages, 6731 KiB

Open AccessArticle

Optimal Design of Water Treatment Contact Tanks

by Mustafa M. Aral

Water 2022, 14(6), 973; https://doi.org/10.3390/w14060973 - 19 Mar 2022

Cited by 1 | Viewed by 10975

Abstract

In water treatment facilities, the last step of the treatment process includes disinfectant application to improve the water quality appropriate for a specific end-use purpose. At this step, contact tanks are used to mix water with the disinfectant. Mixing in contact tanks mainly [...] Read more.

In water treatment facilities, the last step of the treatment process includes disinfectant application to improve the water quality appropriate for a specific end-use purpose. At this step, contact tanks are used to mix water with the disinfectant. Mixing in contact tanks mainly relies on mechanical mixing processes to mix water with the disinfectant to activate the removal process. Thus, mixing efficiency of the contact tank design is critical for the reduction in the amount of disinfectant used to treat a fixed volume of water, to reduce the energy requirements to derive the treated volume of water through the system and to improve other design considerations of the contact tanks. There are numerous design alternatives reported in the literature that do achieve some of these purposes to a certain extent. Among the recent and more successful designs, one can cite the slot-baffle, the perforated-baffle, and the porous-baffle designs. Although these designs provide important improvements to the mixing process, the studies in which these concepts are reported did not provide an optimal design for the baffle geometry used in the design that would include other important considerations beyond the baffle geometry. In this paper, a new optimal design concept is introduced where important design considerations that are not considered in earlier studies are included in the analysis. The results show that new baffle geometries are possible for the optimal design of contact tanks when these innovative design criteria are included in the analysis. Full article

(This article belongs to the Special Issue Artificial Intelligence and Machine Learning Applications in Water Resources Management)

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19 pages, 5612 KiB

Open AccessArticle

Developing Predictive Equations for Water Capturing Performance and Sediment Release Efficiency for Coanda Intakes Using Artificial Intelligence Methods

by Oğuz Hazar, Gokmen Tayfur, Sebnem Elçi and Vijay P. Singh

Water 2022, 14(6), 972; https://doi.org/10.3390/w14060972 - 19 Mar 2022

Cited by 3 | Viewed by 2527

Abstract

Estimation of withdrawal water and filtered sediment amounts are important to obtain maximum efficiency from an intake structure. The purpose of this study is to develop empirical equations to predict Water Capturing Performance (WCP) and Sediment Release Efficiency (SRE) for Coanda type intakes. [...] Read more.

Estimation of withdrawal water and filtered sediment amounts are important to obtain maximum efficiency from an intake structure. The purpose of this study is to develop empirical equations to predict Water Capturing Performance (WCP) and Sediment Release Efficiency (SRE) for Coanda type intakes. These equations were developed using 216 sets of experimental data. Intakes were tested under six different slopes, six screens, and three water discharges. In SRE experiments, sediment concentration was kept constant. Dimensionless parameters were first developed and then subjected to multicollinearity analysis. Then, nonlinear equations were proposed whose exponents and coefficients were obtained using the Genetic Algorithm method. The equations were calibrated and validated with 70 and 30% of the data, respectively. The validation results revealed that the empirical equations produced low MAE and RMSE and high R² values for both the WCP and the SRE. Results showed outperformance of the empirical equations against those of MNLR. Sensitivity analysis carried out by the ANNs revealed that the geometric parameters of the intake were comparably more sensitive than the flow characteristics. Full article

(This article belongs to the Special Issue Artificial Intelligence and Machine Learning Applications in Water Resources Management)

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27 pages, 4632 KiB

Open AccessArticle

Diversity and Vertical Distribution of Sedimentary Bacterial Communities and Its Association with Metal Bioavailability in Three Distinct Mangrove Reserves of South China

by Bochao Hu, Junxian Liao, Qijiong Zhang, Suli Ding, Mengyuan He, Yue Qiao, Zuye Zhang, Chenjing Shang and Si Chen

Water 2022, 14(6), 971; https://doi.org/10.3390/w14060971 - 19 Mar 2022

Cited by 6 | Viewed by 3025

Abstract

The structure of sedimentary bacterial communities in mangroves depends on environmental factors such as pH, salinity, organic matter content, and metal pollution. To investigate the effect of heavy metal pollution on such communities, core samples of sediments from four sites in three distinct [...] Read more.

The structure of sedimentary bacterial communities in mangroves depends on environmental factors such as pH, salinity, organic matter content, and metal pollution. To investigate the effect of heavy metal pollution on such communities, core samples of sediments from four sites in three distinct mangrove reserves (Golden Bay Mangrove Reserve in Beihai, Guangxi province (GXJHW), Shankou Mangrove Reserve in Hepu, Guangxi province (GXSK), and MaiPo mangrove in Hong Kong (MPCT and MPFQ)) in South China were analyzed for physicochemical properties, multiple chemical forms of metals, and vertical bacterial diversity. Sedimentary bacterial communities varied greatly among the different sampling sites, with biodiversity decreasing in the order of GXSK, GXJHW, MPFQ, and MPCT. Proteobacteria was the dominant phylum, followed by Chloroflexi, across all four sampling sites. Multivariate statistical analysis of the effect of environmental factors on the sedimentary bacterial communities found that total carbon was the only physicochemical factor with a significant influence at all four sites. The correlations between environmental factors and bacterial structure were weak for the two sites in Guangxi province, but strong at MPCT in Hong Kong where environmental factors were almost all significantly negatively correlated with bacterial diversity. Variance partitioning analysis revealed that physicochemical properties and chemical forms of metals could explain most of the changes in bacterial diversity. Overall, we observed that heavy metal forms were more important than total metal content in influencing the sedimentary bacterial diversity in mangroves, consistent with the more bioavailable metal species having the greatest effect. Full article

(This article belongs to the Special Issue Origin and Dynamic of Micropollutants in Contaminated River, Estuary, and Surrounding Coastal Water Systems)

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14 pages, 751 KiB

Open AccessReview

Greenhouse Gases Trade-Off from Ponds: An Overview of Emission Process and Their Driving Factors

by Sandeep K. Malyan, Omkar Singh, Amit Kumar, Gagan Anand, Rajesh Singh, Sandeep Singh, Zhiguo Yu, Jhlaesh Kumar, Ram K. Fagodiya and Amit Kumar

Water 2022, 14(6), 970; https://doi.org/10.3390/w14060970 - 19 Mar 2022

Cited by 25 | Viewed by 12492

Abstract

Inland water bodies (particularly ponds) emit a significant amount of greenhouse gases (GHGs), particularly methane (CH₄), carbon dioxide (CO₂), and a comparatively low amount of nitrous oxide (N₂O) to the atmosphere. In recent decades, ponds (<10,000 m [...] Read more.

Inland water bodies (particularly ponds) emit a significant amount of greenhouse gases (GHGs), particularly methane (CH₄), carbon dioxide (CO₂), and a comparatively low amount of nitrous oxide (N₂O) to the atmosphere. In recent decades, ponds (<10,000 m²) probably account for about 1/3rd of the global lake perimeter and are considered a hotspot of GHG emissions. High nutrients and waterlogged conditions provide an ideal environment for CH₄ production and emission. The rate of emissions differs according to climatic regions and is influenced by several biotic and abiotic factors, such as temperature, nutrients (C, N, & P), pH, dissolved oxygen, sediments, water depth, etc. Moreover, micro and macro planktons play a significant role in CO₂ and CH₄ emissions from ponds systems. Generally, in freshwater bodies, the produced N₂O diffuses in the water and is converted into N₂ gas through different biological processes. There are several other factors and mechanisms which significantly affect the CH₄ and CO₂ emission rate from ponds and need a comprehensive evaluation. This study aims to develop a decisive understanding of GHG emissions mechanisms, processes, and methods of measurement from ponds. Key factors affecting the emissions rate will also be discussed. This review will be highly useful for the environmentalists, policymakers, and water resources planners and managers to take suitable mitigation measures in advance so that the climatic impact could be reduced in the future. Full article

(This article belongs to the Special Issue Greenhouse Gas Emission from Freshwater Ecosystem)

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10 pages, 283 KiB

Open AccessArticle

The Effects of Contrast between Dark- and Light-Coloured Tanks on the Growth Performance and Antioxidant Parameters of Juvenile European Perch (Perca fluviatilis)

by Áron Molnár, Dávid Zoltán Homoki, Péter Bársony, Attila Kertész, Judit Remenyik, Georgina Pesti-Asbóth and Milán Fehér

Water 2022, 14(6), 969; https://doi.org/10.3390/w14060969 - 18 Mar 2022

Cited by 2 | Viewed by 2497

Abstract

European perch (Perca fluviatilis) is a predatory fish species with a high degree of stress sensitivity during rearing in intensive systems. Our study was focused on the effects of contrast between two colours (black and light grey) in different parts of [...] Read more.

European perch (Perca fluviatilis) is a predatory fish species with a high degree of stress sensitivity during rearing in intensive systems. Our study was focused on the effects of contrast between two colours (black and light grey) in different parts of a tank (bottom and sidewall) on the production and antioxidant parameters of juvenile European perch during intensive rearing. The duration of the experiment was 8 weeks. In the first treatment, the bottoms of the tanks were black (DB); in the second treatment, the sides of the tank were black (DS); in the control treatment, the fish were kept in light-grey tanks (K). There were three replicates per treatment, and a total of 180 individuals were used; therefore, 60 individuals were used per treatment, with 20 individuals per tank. The mean body weight of the fish at the start of the experiment was 32.01 ± 0.79 g. At the end of the experiment, the antioxidant parameters (cortisol, glucose, MDA, catalase, vitamin C, GPx, GR, GSH, GSSG, and HSP70) of the fish were determined from blood samples. The results of our experiment show that different levels of contrast between the dark and light tank colours significantly influenced the production and antioxidant parameters of the juvenile European perch. Full article

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

19 pages, 13928 KiB

Open AccessFeature PaperArticle

Sequence Analysis of Ancient River Blocking Events in SE Tibetan Plateau Using Multidisciplinary Approaches

by Yiwei Zhang, Jianping Chen, Qing Wang, Yongchao Li, Shengyuan Song, Feifan Gu and Chen Cao

Water 2022, 14(6), 968; https://doi.org/10.3390/w14060968 - 18 Mar 2022

Cited by 1 | Viewed by 2482

Abstract

The temporary or permanent river blocking event caused by mass movement usually occurs on steep terrain. With the increase of mountain population and land use pressure and the construction of water conservancy and hydropower projects, river blocking events have gradually attracted people’s attention [...] Read more.

The temporary or permanent river blocking event caused by mass movement usually occurs on steep terrain. With the increase of mountain population and land use pressure and the construction of water conservancy and hydropower projects, river blocking events have gradually attracted people’s attention and understanding. The area in this study is affected by strong tectonic activity in the Jinsha River suture zone and the rapid uplift of the Tibetan Plateau. In the past 6000 years, there have been at least five obvious river blocking events in the reach. The number and density are very rare. Combining field investigation, indoor interpretation, laboratory tests, optically stimulated luminescence (OSL) dating, SBAS-InSAR and previous studies, multidisciplinary approaches are used to systematically summarize the analysis methods and further the understanding of one river blocking event and multiple river blocking events from different perspectives. Especially in multiple river blocking events, we can get the wrong results if interaction is not considered. Through this study, the general method of analyzing the river blocking event and the problems that should be paid attention to in sampling are given, and relatively reliable historical results of river blocking events are obtained. This method has applicability to the identification and analysis of river blocking events and age determination of dams with multiple river blockages. Full article

(This article belongs to the Topic Natural Hazards and Disaster Risks Reduction)

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20 pages, 5940 KiB

Open AccessArticle

Global-Scale Assessment of Economic Losses Caused by Flood-Related Business Interruption

by Ryo Taguchi, Masahiro Tanoue, Dai Yamazaki and Yukiko Hirabayashi

Water 2022, 14(6), 967; https://doi.org/10.3390/w14060967 - 18 Mar 2022

Cited by 11 | Viewed by 7452

Abstract

Estimating river flood risk helps us to develop strategies for reducing the economic losses and making a resilient society. Flood-related economic losses can be categorized as direct asset damage, opportunity losses because of business interruption (BI loss), and high-order propagation effects on global [...] Read more.

Estimating river flood risk helps us to develop strategies for reducing the economic losses and making a resilient society. Flood-related economic losses can be categorized as direct asset damage, opportunity losses because of business interruption (BI loss), and high-order propagation effects on global trade networks. Biases in meteorological data obtained from climate models hinder the estimation of BI loss because of inaccurate input data including inundation extent and period. In this study, we estimated BI loss and asset damage using a global river and inundation model driven by a recently developed bias-corrected meteorological forcing scheme. The results from the bias-corrected forcing scheme showed an estimated global BI loss and asset damage of USD 26.9 and 130.9 billion (2005 purchase power party, PPP) (1960–2013 average), respectively. Although some regional differences were detected, the estimated BI loss was similar in magnitude to reported historical flood losses. BI loss tended to be greater in river basins with mild slopes such as the Amazon, which has a long inundation period. Future flood risk projection using the same framework under Representative Concentration Pathway 8.5 (RCP8.5) and Shared Socioeconomic Pathway 3 (SSP3) scenarios showed increases in BI loss and asset damage per GDP by 0.32% and 1.78% (2061–2090 average) compared with a past period (1971–2000 average), respectively. Full article

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21 pages, 5276 KiB

Open AccessArticle

Managing Aquifer Recharge to Overcome Overdraft in the Lower American River, California, USA

by Mahesh L. Maskey, Mustafa S. Dogan, Angel Santiago Fernandez-Bou, Liying Li, Alexander Guzman, Wyatt Arnold, Erfan Goharian, Jay R. Lund and Josue Medellin-Azuara

Water 2022, 14(6), 966; https://doi.org/10.3390/w14060966 - 18 Mar 2022

Cited by 8 | Viewed by 3444

Abstract

Frequent and prolonged droughts challenge groundwater sustainability in California but managing aquifer recharge can help to partially offset groundwater overdraft. Here, we use managed aquifer recharge (MAR) to examine potential benefits of adding an artificial recharge facility downstream from California’s Lower American River [...] Read more.

Frequent and prolonged droughts challenge groundwater sustainability in California but managing aquifer recharge can help to partially offset groundwater overdraft. Here, we use managed aquifer recharge (MAR) to examine potential benefits of adding an artificial recharge facility downstream from California’s Lower American River Basin, in part to prepare for drought. We use a statewide hydroeconomic model, CALVIN, which integrates hydrology, the economics of water scarcity cost and operations, environmental flow requirements, and other operational constraints, and allocates water monthly to minimize total scarcity and operating costs. This study considers a recharge facility with unconstrained and constrained flows. The results show that adding a recharge facility increases groundwater storage, reduces groundwater overdraft, and increases hydropower without substantially impacting environmental flows. Further, artificial recharge adds economic benefits by (1) reducing the combined costs of water shortage and surface water storage and (2) by increasing hydropower revenue. This study provides a benchmark tool to evaluate the economic feasibility and water supply reliability impacts of artificial recharge in California. Full article

(This article belongs to the Special Issue Integrated Water Resource System Modeling to Support Sustainable Water Management)

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