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Water, Volume 11, Issue 8 (August 2019)

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Open AccessArticle
Fish Response to Turbulence Generated Using Multiple Randomly Actuated Synthetic Jet Arrays
Water 2019, 11(8), 1715; https://doi.org/10.3390/w11081715 (registering DOI)
Received: 16 May 2019 / Revised: 27 June 2019 / Accepted: 18 July 2019 / Published: 17 August 2019
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Abstract
Hydroelectric power stations generate turbulent flow conditions, which represent a potentially significant hydraulic stressor to fish passing through the turbine system. A test facility has been developed using two randomly actuated synthetic jet arrays (RASJAs) of 25 independent submersible pumps to generate a [...] Read more.
Hydroelectric power stations generate turbulent flow conditions, which represent a potentially significant hydraulic stressor to fish passing through the turbine system. A test facility has been developed using two randomly actuated synthetic jet arrays (RASJAs) of 25 independent submersible pumps to generate a turbulent flow field for biological dose-response testing. The novel elements of this approach include the ability to control the exposure duration within a test volume due to low mean flow velocity as well as the capacity to scale the turbulence levels as a function of pump capacity. Juvenile Chinook salmon (Oncorhynchus tshawytscha) were subjected to the turbulent flow regime with average turbulence kinetic energy per unit mass of 0.089 m 2 / s 2 for periods of 2 min and 10 min. No significant loss of equilibrium or disorientation was observed after exposure for either duration at the level of turbulence achieved in this prototype. Further scaling of this approach is required to generate a complete dose-response relationship. Full article
(This article belongs to the Section Hydraulics)
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Open AccessFeature PaperArticle
Assessing the Efficiency of Alternative Best Management Practices to Reduce Nonpoint Source Pollution in a Rural Watershed Located in Louisiana, USA
Water 2019, 11(8), 1714; https://doi.org/10.3390/w11081714 (registering DOI)
Received: 21 June 2019 / Revised: 12 August 2019 / Accepted: 12 August 2019 / Published: 17 August 2019
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Abstract
We conducted biophysical simulations using MapShed to determine the effects of adopting best management practices (BMPs) to reduce nutrients and sediment pollution in a watershed dominated by poultry production in the Saline Bayou Watershed, Louisiana, USA. The reduction of three water pollutants, nitrogen, [...] Read more.
We conducted biophysical simulations using MapShed to determine the effects of adopting best management practices (BMPs) to reduce nutrients and sediment pollution in a watershed dominated by poultry production in the Saline Bayou Watershed, Louisiana, USA. The reduction of three water pollutants, nitrogen, phosphorus, and sediment from adopting different BMPs were assessed using a linear programming model with the cost minimization objective. We considered three weather scenarios (dry, normal, and wet) and BMP parameter efficiencies obtained from linear regression models. Optimization results showed that nutrient management and agricultural land retirement reduced most of the phosphorus runoff in the watershed at the lowest cost. Results were robust to alternative weather (dry, normal, and wet) scenarios. Full article
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Open AccessArticle
Validation of the 3D-MOHID Hydrodynamic Model for the Tagus Coastal Area
Water 2019, 11(8), 1713; https://doi.org/10.3390/w11081713 (registering DOI)
Received: 13 July 2019 / Revised: 13 August 2019 / Accepted: 14 August 2019 / Published: 17 August 2019
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Abstract
The hydrodynamics of the TagusROFI (Regions of Freshwater Influence) is affected by the coastal upwelling, the estuarine tidal flow, the thermohaline circulation that is modulated by the Tagus freshwater discharge, and by its complex bathymetry. The use of numerical models is the best [...] Read more.
The hydrodynamics of the TagusROFI (Regions of Freshwater Influence) is affected by the coastal upwelling, the estuarine tidal flow, the thermohaline circulation that is modulated by the Tagus freshwater discharge, and by its complex bathymetry. The use of numerical models is the best way to explain the processes that characterize this region. These models are also crucial to answer important scientific and management questions. Nevertheless, the robustness of the products derived from models depend on their accuracy and therefore models must be validated to determine the uncertainty associated. Time and space variability of the driving forces and of bathymetry enhance flow complexity increasing validation difficulties, requiring continuous high-resolution data to describe flow and thermohaline horizontal and vertical variabilities. In the present work, to increase the precision and accuracy of the coastal processes simulations, the sub-systems coastal area and the Tagus estuary were integrated into a single domain, which considers higher resolution grids in both horizontal and vertical directions. The three-dimensiosal (3D)-MOHID Water model was validated for the TagusROFI by comparing statistically modelling results with in situ and satellite L4 data. Validation with a conductivity, temperature, and depth probe (CTD), an acoustic doppler current profiler (ADCP) and satellite data was performed for the first time. Validation against tidal gauges showed that the model is able to simulate tidal propagation inside the estuary with accuracy. A very good agreement between CTD data and surface sea water temperature (SST) and salinity simulations was observed. The validation of current direction and velocity from ADCP data also indicated a high model accuracy for these variables. Comparisons between model and satellite for SST also showed that the model produces realistic SSTs and upwelling events. Overall results showed that MOHID setup and parametrisations are well implemented for the TagusROFI domain. These results are even more important when a 3D model is used in simulations due to its complexity once it considers both horizontal and vertical discretization allowing a better representation of the heat and salinity fluxes in the water column. Moreover, the results achieved indicates that 3D-MOHID is robust enough to run in operational mode, including its forecast ability, fundamental to be used as a management tool. Full article
(This article belongs to the Section Hydrology)
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Open AccessArticle
Capability of Diffuse Reflectance Spectroscopy to Predict Soil Water Retention and Related Soil Properties in an Irrigated Lowland District of Southern Italy
Water 2019, 11(8), 1712; https://doi.org/10.3390/w11081712 (registering DOI)
Received: 26 June 2019 / Revised: 9 August 2019 / Accepted: 11 August 2019 / Published: 17 August 2019
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Abstract
In this study, we examined the potential of vis-NIR reflectance spectroscopy, coupled with partial least squares regression (PLSR) analysis, for the evaluation and prediction of soil water retention at field capacity (FC) and permanent wilting point (PWP) and related basic soil properties [organic [...] Read more.
In this study, we examined the potential of vis-NIR reflectance spectroscopy, coupled with partial least squares regression (PLSR) analysis, for the evaluation and prediction of soil water retention at field capacity (FC) and permanent wilting point (PWP) and related basic soil properties [organic carbon (OC), sand, silt, and clay contents] in an agricultural irrigated land of southern Italy. Soil properties were determined in the laboratory with reference to the Italian Official Methods for Soil Analysis. Vis-NIR reflectance spectra were measured in the laboratory, using a high-resolution spectroradiometer. All soil variables, with the exception of silt, evidently affected some specific spectral features. Multivariate calibrations were performed to predict the soil properties from reflectance spectra. PLSR was used to calibrate the spectral data using two-thirds of samples for calibration and one-third for validation. Spectroscopic data were pre-processed [multiplicative scatter correction (MSC), standard normal variance (SNV), wavelet detrending (WD), first and second derivative transformation, and filtering] prior to multivariate calibration. The results revealed very good models (2.0 < RPD < 2.5) for the prediction of FC, PWP and sand, and excellent (RPD > 2.5) models for the prediction of clay and OC, whereas a poor (RPD < 1.4) prediction model was obtained for silt. Full article
(This article belongs to the Special Issue Evapotranspiration and Plant Irrigation Strategies)
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Open AccessArticle
Impact of Nutrient and Stoichiometry Gradients on Microbial Assemblages in Erhai Lake and Its Input Streams
Water 2019, 11(8), 1711; https://doi.org/10.3390/w11081711 (registering DOI)
Received: 23 July 2019 / Revised: 9 August 2019 / Accepted: 13 August 2019 / Published: 17 August 2019
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Abstract
Networks of lakes and streams are linked by downslope flows of material and energy within catchments. Understanding how bacterial assemblages are associated with nutrients and stoichiometric gradients in lakes and streams is essential for understanding biogeochemical cycling in freshwater ecosystems. In this study, [...] Read more.
Networks of lakes and streams are linked by downslope flows of material and energy within catchments. Understanding how bacterial assemblages are associated with nutrients and stoichiometric gradients in lakes and streams is essential for understanding biogeochemical cycling in freshwater ecosystems. In this study, we conducted field sampling of bacterial communities from lake water and stream biofilms in Erhai Lake watershed. We determined bacterial communities using high-throughput 16S rRNA gene sequencing and explored the relationship between bacterial composition and environmental factors using networking analysis, canonical correspondence analysis (CCA), and variation partitioning analysis (VPA). Physicochemical parameters, nutrients, and nutrient ratios gradients between the lake and the streams were strongly associated with the differences in community composition and the dominant taxa. Cyanobacteria dominated in Erhai Lake, while Proteobacteria dominated in streams. The stream bacterial network was more stable with multiple stressors, including physicochemical-factors and nutrient-factors, while the lake bacterial network was more fragile and susceptible to human activities with dominant nutrients (phosphorus). Negative correlations between bacterial communities and soluble reactive phosphorus (SRP) as well as positive correlations between bacterial communities and dissolved organic carbon (DOC) in the network indicated these factors had strong effect on bacterial succession. Erhai Lake is in a eutrophic state, and high relative abundances of Synechococcus (40.62%) and Microcystis (16.2%) were noted during the course of our study. CCA indicated that nutrients (phosphorus) were key parameters driving Cyanobacteria-dominated community structure. By classifying the environmental factors into five categories, VPA analyses identified that P-factor (total phosphorus (TP) and SRP) as well as the synergistic effect of C-factor (DOC), N-factor (NO3), and P-factor (TP and SRP) played a central role in structuring the bacterial communities in Erhai Lake. Heterogeneous physicochemical conditions explained the variations in bacterial assemblages in streams. This study provides a picture of stream–lake linkages from the perspective of bacterial community structure as well as key factors driving bacterial assemblages within lakes and streams at the whole watershed scale. We further argue that better management of phosphorus on the watershed scale is needed for ameliorating eutrophication of Erhai Lake. Full article
(This article belongs to the Special Issue Advancing Knowledge on Cyanobacterial Blooms in Freshwaters)
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Open AccessArticle
Zwitterion-Modified Ultrafiltration Membranes for Permian Basin Produced Water Pretreatment
Water 2019, 11(8), 1710; https://doi.org/10.3390/w11081710 (registering DOI)
Received: 5 July 2019 / Revised: 14 August 2019 / Accepted: 15 August 2019 / Published: 17 August 2019
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Abstract
Unconventional oil and gas extraction generates large quantities of produced water (PW). Due to strict environmental regulations, it is important to recover and reuse PW. In this study, commercial polyethersulfone (PES) ultrafiltration (UF) membranes were surface-modified with zwitterionic polymer 3-(3,4-Dihydroxyphenyl)-l-alanine ( [...] Read more.
Unconventional oil and gas extraction generates large quantities of produced water (PW). Due to strict environmental regulations, it is important to recover and reuse PW. In this study, commercial polyethersulfone (PES) ultrafiltration (UF) membranes were surface-modified with zwitterionic polymer 3-(3,4-Dihydroxyphenyl)-l-alanine (l-DOPA) solution to alleviate membrane fouling during the ultrafiltration of shale oil PW of the Permian Basin. UF membranes were coated in l-DOPA solution by using a dip coating technique. Membrane characterization tests confirmed successful l-DOPA coating on UF membranes. While performing the experiments, permeate flux behaviors of the uncoated and coated membranes and antifouling resistance of the zwitterionic coating were evaluated. Among the coated UF membranes with varying coating times from one day to three days, the three-day coated UF membrane showed a good flux performance and the highest fouling resistance. The flux reduced by 38.4% for the uncoated membrane, while the reduction was 16% for the three-day coated membrane after the 5 h ultrafiltration of PW. Both improvements of the flux performance and recovery ratio are attributed to a negatively-charged surface developed on the membranes after the zwitterionic coating. The UF pretreatment also improved the flux behavior of the later forward osmosis (FO) process for PW treatment. Full article
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Open AccessArticle
Potential Transformative Changes in Water Provision Systems: Impact of Decentralised Water Systems on Centralised Water Supply Regime
Water 2019, 11(8), 1709; https://doi.org/10.3390/w11081709 (registering DOI)
Received: 15 July 2019 / Revised: 9 August 2019 / Accepted: 13 August 2019 / Published: 16 August 2019
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Abstract
Sustainable Urban Water Management (SUWM) is a paradigm in which decentralisation is key. There has been little work directed towards the large-scale possibilities of decentralised water systems and their implications on the functioning of the centralised (potable) water system. This study includes both [...] Read more.
Sustainable Urban Water Management (SUWM) is a paradigm in which decentralisation is key. There has been little work directed towards the large-scale possibilities of decentralised water systems and their implications on the functioning of the centralised (potable) water system. This study includes both a historical and future (scenario) analysis of decentralised developments. Integrated morphological socio-technical scenarios are combined with quantitative water flows for a case study (the Province of Limburg, the Netherlands) and examined by a transdisciplinary group of experts. The study shows how SUWM measures which focus on climate adaptation and circularity can have a significant impact on existing centralised potable water systems. In turn, influencing the total water and peak demands and thus resulting in different utilisation rates. This can result in more system failures (e.g., longer residence time, bacterial growth, reduced self-cleaning capacity), significant changes in the centralised infrastructure (e.g., more wells), increasing water bills (e.g., inequalities), and the preservation of aquifers for future generation. Different scenarios either have regime-reproducing or regime-diversifying impacts. SUWM measures are studied in isolation and thus externalities are not fully considered. Therefore, when planning for decentralised SUWM solutions, a systems thinking approach is recommended, which takes into account externalities. Full article
(This article belongs to the Special Issue Systems Thinking and Urban Water Cycle Management)
Open AccessArticle
Evaluating Water Resource Accessibility in Southwest China
Water 2019, 11(8), 1708; https://doi.org/10.3390/w11081708 (registering DOI)
Received: 18 July 2019 / Revised: 11 August 2019 / Accepted: 14 August 2019 / Published: 16 August 2019
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Abstract
The accessibility, quantity, and quality of water resources are the basic requirements for guaranteeing water resource security. Research into regional water resource accessibility will contribute to improving regional water resource security and effective water resource management. In this study, we used a water [...] Read more.
The accessibility, quantity, and quality of water resources are the basic requirements for guaranteeing water resource security. Research into regional water resource accessibility will contribute to improving regional water resource security and effective water resource management. In this study, we used a water resource accessibility index model considering five spatial factors to evaluate the grid-scale water resource accessibility and constructed the spatial pattern of water resource accessibility in Southwest China. Then, we analyzed the coupling coordination degree between county-level water resource accessibility and eco-socio-economic water demand elements. The water resource accessibility showed obvious regional differences, and the overall trend gradually decreased from Southeast to Northwest. The coupling coordination degree between county-level water resource accessibility and eco-socio-economic water demand elements was between 0.26 and 0.84, and was relatively low overall, whereas the counties (districts) with high coordination, moderate coordination, low coordination, reluctant coordination, and incoordination accounted for 0.92%, 5.31%, 21.06%, 59.71%, and 13.00% of total counties (districts), respectively. Therefore, the Southwest region needs to further strengthen the construction of its agricultural irrigation facilities, protect the water resources, and coordinate the relationship between water resource management and water demand elements to comprehensively guarantee regional sustainable development. Full article
(This article belongs to the Special Issue Water Resources Management Models for Policy Assessment)
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Open AccessArticle
Inter-Comparison of Different Bayesian Model Averaging Modifications in Streamflow Simulation
Water 2019, 11(8), 1707; https://doi.org/10.3390/w11081707 (registering DOI)
Received: 16 June 2019 / Revised: 9 August 2019 / Accepted: 13 August 2019 / Published: 16 August 2019
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Abstract
Bayesian model averaging (BMA) is a popular method using the advantages of forecast ensemble to enhance the reliability and accuracy of predictions. The inherent assumptions of the classical BMA has led to different variants. However, there is not a comprehensive examination of how [...] Read more.
Bayesian model averaging (BMA) is a popular method using the advantages of forecast ensemble to enhance the reliability and accuracy of predictions. The inherent assumptions of the classical BMA has led to different variants. However, there is not a comprehensive examination of how these solutions improve the original BMA in the context of streamflow simulation. In this study, a scenario-based analysis was conducted for assessment of various modifications and how they affect BMA results. The evaluated modifications included using various streamflow ensembles, data transformation procedures, distribution types, standard deviation forms, and optimization methods. We applied the proposed analysis in two data-poor watersheds located in northern Ontario, Canada. The results indicate that using more representative distribution types do not significantly improve BMA-derived results, while the positive effect of implementing non-constant variance on BMA probabilistic performance cannot be ignored. Also, higher reliability was obtained by applying a data transformation procedure; however, it can reduce the results’ sharpness significantly. Moreover, although considering many streamflow simulations as ensemble members does not always enhance BMA results, using different forcing precipitation scenarios besides multi-models led to better BMA-based probabilistic simulations in data-poor watersheds. Also, the reliability of the expectation-maximization algorithm in estimating BMA parameters was confirmed. Full article
(This article belongs to the Section Hydrology)
Open AccessArticle
Calibration and Optimization of the Ångström–Prescott Coefficients for Calculating ET0 within a Year in China: The Best Corrected Data Time Scale and Optimization Parameters
Water 2019, 11(8), 1706; https://doi.org/10.3390/w11081706 (registering DOI)
Received: 11 June 2019 / Revised: 31 July 2019 / Accepted: 14 August 2019 / Published: 16 August 2019
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Abstract
This study used meteorological data from official data sets to correct Ångström–Prescott formula parameters for China’s agricultural zones for which existing research encountered the problem of spatio-temporal scale disunity. The data, collected from 124 stations, were used to correct the as and [...] Read more.
This study used meteorological data from official data sets to correct Ångström–Prescott formula parameters for China’s agricultural zones for which existing research encountered the problem of spatio-temporal scale disunity. The data, collected from 124 stations, were used to correct the as and bs coefficients of the Ångström–Prescott formula, by area, at 5–50 year-scales, the former taking into account China’s comprehensive agricultural zones. We focused on how the as and bs obtained from the different time scales corrected data affected the calculating solar radiation (Rs_c) precision, determined the optimal time scale for the corrected data, and compared and selected the as and bs with the minimum estimation error as the recommended values. The results show that our corrected as and bs coefficient values significantly reduce the range of the relative error of Rs_c, with 10 years being the best time scale for the corrected data. Further, the Rs_c precisions estimated by as and bs coefficients based on the Food and Agriculture Organization of the United Nations (FAO) and the regression result of the best time scale corrected data are inconsistent in different months by area. The best choice in practice is combining the two coefficients and optimizing their use. This study provides a research-based process for standardizing the correction of Ångström–Prescott formula parameters and selecting the corrected data time scale in China. It would be helpful in improving the calculation accuracy for reference crop evapotranspiration (ET0). Full article
(This article belongs to the Section Water–Food–Energy Nexus)
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Open AccessFeature PaperArticle
Spatiotemporal Variations of Summer Precipitation and Their Correlations with the East Asian Summer Monsoon in the Poyang Lake Basin, China
Water 2019, 11(8), 1705; https://doi.org/10.3390/w11081705 (registering DOI)
Received: 27 June 2019 / Revised: 3 August 2019 / Accepted: 13 August 2019 / Published: 16 August 2019
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Abstract
Poyang Lake Basin (PYLB) is located in Southeastern China where the precipitation is closely related to the East Asian Monsoon. Based on the monthly precipitation data of 18 meteorological stations from 1959 to 2018 in the PYLB, Empirical Orthogonal Function (EOF), Wavelet Analysis, [...] Read more.
Poyang Lake Basin (PYLB) is located in Southeastern China where the precipitation is closely related to the East Asian Monsoon. Based on the monthly precipitation data of 18 meteorological stations from 1959 to 2018 in the PYLB, Empirical Orthogonal Function (EOF), Wavelet Analysis, and Pearson Correlation Analysis were used to investigate the spatiotemporal variations of summer precipitation and their correlations with the East Asian Summer Monsoon (EASM). The results demonstrate that there were two leading modes of summer precipitation at inter-annual time scales: the mode being consistent over the whole area and the mode of opposite relationship between the south/north PYLB. Both modes had obvious trend variations and periodic characteristics. The East Asian Summer Monsoon Index (EASMI) showed a decreasing trend of fluctuation, existing in periods of 2–3 years and 11 years. Cross Wavelet Transform revealed that the time coefficients of the second EOF mode and EASMI had an anti-phase resonance period of 2–3 years. Pearson Correlation Analysis also indicated that there was a significant negative correlation relationship between them. These results not only contribute to an understanding of characteristics of summer precipitation in the PYLB and the influences of the East Asian Summer Monsoon on them but also provide a reference for a regional response to climate change and precipitation prediction. Full article
(This article belongs to the Special Issue Wetland Ecohydrology and Water Resource Management)
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Open AccessArticle
Sensitivity Analysis on the Rising Relation between Short-Term Rainfall and Groundwater Table Adjacent to an Artificial Recharge Lake
Water 2019, 11(8), 1704; https://doi.org/10.3390/w11081704 (registering DOI)
Received: 15 July 2019 / Revised: 13 August 2019 / Accepted: 14 August 2019 / Published: 16 August 2019
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Abstract
This study aimed to determine the highly sensitive variables for a groundwater simulation model adjacent to an artificial recharge lake (ARL) using short-term rainfall events. The model was established using an artificial neural network (ANN) with rainfall events. Normalized rainfall, rainfall intensity, and [...] Read more.
This study aimed to determine the highly sensitive variables for a groundwater simulation model adjacent to an artificial recharge lake (ARL) using short-term rainfall events. The model was established using an artificial neural network (ANN) with rainfall events. Normalized rainfall, rainfall intensity, and groundwater data were selected as model variables. The coefficient of determination (R2) was used for model performance assessment. Finally, a sensitivity analysis (SA) was conducted to evaluate the importance of each model input. The study results indicated that the R2 of the ANN model ranged between 0.759 and 0.914. The SA showed that the rainfall was more sensitive than rainfall intensity in the study area. Based on the SA results and relevant geological characteristics, it was observed that the rainfall of past 1-day, past 2-day, and past 3-day responded faster than the other variables to the wells near the river and the ARL. In addition, the past 2-day rainfall was highly sensitive to the groundwater table; this may be due to the fact that the well screen location was above sea level as observed in Wells 1, 2, and 6. The results indicate that the groundwater table variation is response-related to the distance from the wells to the river and the ARL, and the rainfall time-lag. This SA study is helpful to researchers wishing to study related ARL efficiency issues. Full article
(This article belongs to the Special Issue Rainfall Infiltration Modeling)
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Open AccessArticle
The Role of the Spatial Distribution of Radar Rainfall on Hydrological Modeling for an Urbanized River Basin in Japan
Water 2019, 11(8), 1703; https://doi.org/10.3390/w11081703 (registering DOI)
Received: 18 July 2019 / Revised: 13 August 2019 / Accepted: 14 August 2019 / Published: 16 August 2019
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Abstract
Recently, the use of gridded rainfall data with high spatial resolutions in hydrological applications has greatly increased. Various types of radar rainfall data with varying spatial resolutions are available in different countries worldwide. As a result of the variety in spatial resolutions of [...] Read more.
Recently, the use of gridded rainfall data with high spatial resolutions in hydrological applications has greatly increased. Various types of radar rainfall data with varying spatial resolutions are available in different countries worldwide. As a result of the variety in spatial resolutions of available radar rainfall data, the hydrological community faces the challenge of selecting radar rainfall data with an appropriate spatial resolution for hydrological applications. In this study, we consider the impact of the spatial resolution of radar rainfall on simulated river runoff to better understand the impact of radar resolution on hydrological applications. Very high-resolution polarimetric radar rainfall (XRAIN) data are used as input for the Hydrologic Engineering Center–Hydrologic Modeling System (HEC-HMS) to simulate runoff from the Tsurumi River Basin, Japan. A total of 20 independent rainfall events from 2012–2015 were selected and categorized into isolated/convective and widespread/stratiform events based on their distribution patterns. First, the hydrological model was established with basin and model parameters that were optimized for each individual rainfall event; then, the XRAIN data were rescaled at various spatial resolutions to be used as input for the model. Finally, we conducted a statistical analysis of the simulated results to determine the optimum spatial resolution for radar rainfall data used in hydrological modeling. Our results suggest that the hydrological response was more sensitive to isolated or convective rainfall data than it was to widespread rain events, which are best simulated at ≤1 km and ≤5 km, respectively; these results are applicable in all sub-basins of the Tsurumi River Basin, except at the river outlet. Full article
(This article belongs to the Section Hydrology)
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Open AccessArticle
Identification of the Hydrogeochemical Processes and Assessment of Groundwater Quality, Using Multivariate Statistical Approaches and Water Quality Index in a Wastewater Irrigated Region
Water 2019, 11(8), 1702; https://doi.org/10.3390/w11081702 (registering DOI)
Received: 7 June 2019 / Revised: 12 August 2019 / Accepted: 14 August 2019 / Published: 16 August 2019
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Abstract
Groundwater quality and availability are essential for human consumption and social and economic activities in arid and semiarid regions. Many developing countries use wastewater for irrigation, which has in most cases led to groundwater pollution. The Mezquital Valley, a semiarid region in central [...] Read more.
Groundwater quality and availability are essential for human consumption and social and economic activities in arid and semiarid regions. Many developing countries use wastewater for irrigation, which has in most cases led to groundwater pollution. The Mezquital Valley, a semiarid region in central Mexico, is the largest agricultural irrigation region in the world, and it has relied on wastewater from Mexico City for over 100 years. Limited research has been conducted on the impact of irrigation practices on groundwater quality on the Mezquital Valley. In this study, 31 drinking water wells were sampled. Groundwater quality was determined using the water quality index (WQI) for drinking purposes. The hydrogeochemical process and the spatial variability of groundwater quality were analyzed using principal component analysis (PCA) and K-means clustering multivariate geostatistical tools. This study highlights the value of combining various approaches, such as multivariate geostatistical methods and WQI, for the identification of hydrogeochemical processes in the evolution of groundwater in a wastewater irrigated region. The PCA results revealed that salinization and pollution (wastewater irrigation and fertilizers) followed by geogenic sources (dissolution of carbonates) have a significant effect on groundwater quality. Groundwater quality evolution was grouped into cluster 1 and cluster 2, which were classified as unsuitable (low quality) and suitable (acceptable quality) for drinking purposes, respectively. Cluster 1 is located in wastewater irrigated zones, urban areas, and the surroundings of the Tula River. Cluster 2 locations are found in recharge zones, rural settlements, and seasonal agricultural fields. The results of this study strongly suggest that water management strategies that include a groundwater monitoring plan, as well as research-based wastewater irrigation regulations, in the Mezquital Valley are warranted. Full article
(This article belongs to the Section Water Resources Management and Governance)
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Open AccessArticle
A New Metric for Assessing Resilience of Water Distribution Networks
Water 2019, 11(8), 1701; https://doi.org/10.3390/w11081701 (registering DOI)
Received: 22 June 2019 / Revised: 9 August 2019 / Accepted: 14 August 2019 / Published: 16 August 2019
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Abstract
Water distribution networks (WDNs) face various types of hazards during their extended life. Ensuring proper functioning of WDNs has always been a major concern for utility managers because of their impact on public health and safety. Resilience is an emerging concept that aims [...] Read more.
Water distribution networks (WDNs) face various types of hazards during their extended life. Ensuring proper functioning of WDNs has always been a major concern for utility managers because of their impact on public health and safety. Resilience is an emerging concept that aims at maintaining functionality of the WDNs. Most of the previously developed resilience frameworks employed simulation methods to assess resilience of the WDNs, focusing only on the specific aspects of resilience. There is a need to develop a holistic approach to evaluate the resilience of WDNs considering various dimensions of resilience. This paper presents a new multi-attribute resilience metric based on the robustness and redundancy of the WDNs, which can be used to achieve the purpose. The developed metric is used to evaluate the resilience of a WDN in the city of London, Ontario. An optimization framework for enhancing the current resilience level is also presented. Resilience of the network is found to increase around 20% with a $500,000 investment. A hazard scenario is then analyzed to illustrate the practicality of using this metric in selecting effective restoration strategies. The proposed metric can be utilized by water agencies to evaluate and enhance the resilience of WDNs, as well as to optimize the recovery process after disruptive events. Full article
(This article belongs to the Section Urban Water Management)
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Open AccessArticle
Increase and Spatial Variation in Soil Infiltration Rates Associated with Fibrous and Tap Tree Roots
Water 2019, 11(8), 1700; https://doi.org/10.3390/w11081700 (registering DOI)
Received: 15 July 2019 / Revised: 12 August 2019 / Accepted: 13 August 2019 / Published: 16 August 2019
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Abstract
Trees play important roles in urban stormwater management; through the loosening of soils by root growth, they increase infiltration and reduce runoff, helping to mitigate flooding and recharge groundwater. Malus baccata with fibrous roots and Sophora japonica with tap roots were studied experimentally [...] Read more.
Trees play important roles in urban stormwater management; through the loosening of soils by root growth, they increase infiltration and reduce runoff, helping to mitigate flooding and recharge groundwater. Malus baccata with fibrous roots and Sophora japonica with tap roots were studied experimentally to assess their enhancement of soil infiltration. A blank test without a tree was conducted for comparison. Steady-state soil infiltration rates at the bottom of test tanks were measured as 0.28 m/d, 0.33 m/d, and 0.61 m/d for the blank test, M. baccata, and S. japonica, respectively. This represents a 19% increase in the infiltration rate by planting M. baccata and a 118% increase by planting S. japonica. A larger increase in the infiltration rate by S. japonica is consistent with the effects of deeper and more vertical roots that help loosen deeper soils. Spatial variations in soil infiltration rates were also measured. Infiltration rates for M. baccata (1.06 m/d and 0.62 m/d) were larger than those for S. japonica (0.91 m/d and 0.51 m/d) at the same depths (0.35 m and 0.70 m); this is consistent with the expected effects of the shallower and more lateral roots of M. baccata. This study furthers our understanding of the roles of trees in watersheds and urban environments. Full article
(This article belongs to the Special Issue Advances in Groundwater and Surface Water Monitoring and Management)
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Open AccessArticle
Making Birmingham a Flood Resilient City: Challenges and Opportunities
Water 2019, 11(8), 1699; https://doi.org/10.3390/w11081699 (registering DOI)
Received: 31 May 2019 / Revised: 10 August 2019 / Accepted: 13 August 2019 / Published: 16 August 2019
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Abstract
The city of Birmingham has experienced a number of significant flooding events in the past two decades. The impacts of these flood events include physical damage to critical infrastructure, as well as significant losses caused by business interruption and general disruption to communities. [...] Read more.
The city of Birmingham has experienced a number of significant flooding events in the past two decades. The impacts of these flood events include physical damage to critical infrastructure, as well as significant losses caused by business interruption and general disruption to communities. Human losses and impacts can be life changing. This study identifies the current challenges and opportunities of managing flood risk in the city of Birmingham, drawing on a desk-based account of current flood risk management (FRM) practice and diagnostic evidence. This interrogation adopts the use of a ‘flood resilience circle model’ to consider ways to address the challenges in a methodological manner aligned to an integrated approach to flood risk management. Solutions aligned to the key FRM stages of prevention, preparation, response and recovery are provided. The findings will be of interest to policy makers and decision makers on how to address current weaknesses in FRM practices towards the prospect of a sustainable approach that improves the resilience of the city and delivers multiple benefits. Recommendations made include the adoption of a blue-green systems approach, the development of a new communication strategy aligned to motivating behaviour change, and improved flood forecasting especially for surface water flooding. Full article
(This article belongs to the Special Issue Influence of the Urban Fabric on the Risks of Floods)
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Open AccessArticle
Assessment of the Rheological Behavior of Polymer–Oxidant Mixtures and the Influence of the Groundwater Environment on Their Properties
Water 2019, 11(8), 1698; https://doi.org/10.3390/w11081698 (registering DOI)
Received: 5 May 2019 / Revised: 25 July 2019 / Accepted: 13 August 2019 / Published: 16 August 2019
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Abstract
Shear-thinning polymers have been introduced to contaminant remediation in the subsurface as a mobility control method applied to mitigate the inefficient delivery of remedial agents caused by geological heterogeneity. Laboratory experiments have been conducted to assess the compatibility of polymers (xanthan and hydrolyzed [...] Read more.
Shear-thinning polymers have been introduced to contaminant remediation in the subsurface as a mobility control method applied to mitigate the inefficient delivery of remedial agents caused by geological heterogeneity. Laboratory experiments have been conducted to assess the compatibility of polymers (xanthan and hydrolyzed polyacrylamide (HPAM)) and oxidants (KMnO4 and Na2S2O8) through quantitative evaluation of the viscosity maintenance, shear-thinning performance, and oxidant consumption. The mechanism that causes viscosity loss and the influence of the groundwater environment on the mixture viscosity were also explored. The xanthan–KMnO4 mixture exhibited the best performance in both viscosity retention and shear-thinning behavior with retention rates higher than 75% and 73.5%, respectively. Furthermore, the results indicated that xanthan gum has a high resistance to MnO4 and that K+ plays a leading role in its viscosity reduction, while HPAM is much more sensitive to MnO4. The viscosity responses of the two polymers to Na2S2O8 and NaCl were almost consistent with that of KMnO4; salt ions displayed an instantaneous effect on the solution’s viscosity, while the oxide ions could cause the solution’s viscosity to decrease continuously with time. Since xanthan exhibited acceptable oxidant consumption as well, xanthan–KMnO4 is considered to be the optimal combination. In addition, the results implied that the effects of salt ions and the water pH on the mixture solution could be acceptable. In the 2D tank test, it was found that when xanthan gum was introduced, the sweeping efficiency of the oxidant in the low-permeability zone was increased from 28.2% to 100%. These findings demonstrated the feasibility of using a xanthan–KMnO4 mixture for actual site remediation. Full article
(This article belongs to the Section Water Quality and Ecosystems)
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Open AccessCorrection
Correction: Harding, S.F., et al. Experimental Observation of Inertial Particles through Idealized Hydroturbine Distributor Geometry. Water 2019, 11, 471
Water 2019, 11(8), 1697; https://doi.org/10.3390/w11081697
Received: 25 July 2019 / Accepted: 25 July 2019 / Published: 15 August 2019
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Abstract
The authors wish to make the following corrections to their paper [...] Full article
(This article belongs to the Section Hydraulics)
Open AccessArticle
Developing a Strategy to Recover Condensate Water from Air Conditioners in Palestine
Water 2019, 11(8), 1696; https://doi.org/10.3390/w11081696
Received: 4 July 2019 / Revised: 27 July 2019 / Accepted: 30 July 2019 / Published: 15 August 2019
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Abstract
As the need for water is increasing in Palestine, and the available water resources are barely sufficient to meet the demands of the current quality of life and the economy, air conditioner condensate water could be explored as an alternative water source. The [...] Read more.
As the need for water is increasing in Palestine, and the available water resources are barely sufficient to meet the demands of the current quality of life and the economy, air conditioner condensate water could be explored as an alternative water source. The objective of this study is to better understand the potential for recovery of condensate water from air conditioning systems in two Palestinian cities. In addition, this study aims to evaluate this water source in terms of quality and quantity. Generally, it was found that the condensate water has good quality, which conforms to the Palestinian standards for reused water for irrigation, except for turbidity, biological oxygen demand (BOD) and chemical oxygen demand (COD) measurements. Reflecting the heavy metal occurrence in the collected condensate water, no particular risk was recognized for drinking water or reused irrigation standards, except for manganese occurrence of 0.19 mg/L in one sample. From a single unit capacity, high quantities of water were observed of approximately 259 L and 453 L per month in Ramallah and Jericho cities, respectively. These figures should draw the attention of decision and policy makers to put in place strict technical guidelines to be followed for potential reuse of condensate water at the local level. Full article
(This article belongs to the Section Urban Water Management)
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Open AccessArticle
Sulfate Radicals-Based Technology as a Promising Strategy for Wastewater
Water 2019, 11(8), 1695; https://doi.org/10.3390/w11081695
Received: 10 July 2019 / Revised: 12 August 2019 / Accepted: 13 August 2019 / Published: 15 August 2019
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Abstract
This study was focused on the generation of sulfate radicals and their applicability as powerful oxidants for degrading complex organic compounds with the final objective of operating in flow systems. To this end, the removal of two compounds from the pharmaceutical industry was [...] Read more.
This study was focused on the generation of sulfate radicals and their applicability as powerful oxidants for degrading complex organic compounds with the final objective of operating in flow systems. To this end, the removal of two compounds from the pharmaceutical industry was assessed, lissamine green and prednisolone. Initially, sulfate radicals were generated by the activation of persulfate with iron as homogenous catalyst, and the key parameters involved in the process, as catalyst concentration and oxidant dosage, were evaluated. Furthermore, with the aim of preventing the secondary contamination due to metal leaching and to be operate in a continuous mode, a heterogeneous catalyst was developed. For it, the iron was fixed on a cationic resin as Amberlite IR120 Na+ form. It was demonstrated that the removal of both pollutants increases with greater catalyst dosages, achieving a decay of 85% within 25 min with 30 g·L−1 of catalyst. Moreover, the reuse capability of the catalyst was tested, illustrating that it is rough enough for its reuse. Conversely, in order to develop a continuous treatment in flow system, a fixed bed reactor was constructed and its feasibility was proven. Different experiments with residence times from 10 min to 60 min were performed, obtaining a removal level of ≈95% and 90% for prednisolone and lissamine green, respectively, at residence time of 60 min. In conclusion, the potential of sulfate radicals-based technology for degrading organic contaminants has been demonstrated. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Monitoring and Treatment Technology)
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Open AccessArticle
Sustainable Water Resources Management in Small Greek Islands under Changing Climate
Water 2019, 11(8), 1694; https://doi.org/10.3390/w11081694
Received: 28 June 2019 / Revised: 6 August 2019 / Accepted: 12 August 2019 / Published: 15 August 2019
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Abstract
Five different water resource management scenarios are examined on eight dry islands of the Aegean Sea in Greece, pitting the current practice of water hauling via ship against alternative water supply schemes in delivering a sustainable solution for meeting water demand. The first [...] Read more.
Five different water resource management scenarios are examined on eight dry islands of the Aegean Sea in Greece, pitting the current practice of water hauling via ship against alternative water supply schemes in delivering a sustainable solution for meeting water demand. The first scenario employs current water supply practices along with the operation of domestic rainwater harvesting systems. Desalinated water, provided through the operation of wind-powered desalination plants, is considered the main source of potable water in the rest of scenarios. Wind-powered desalination may be combined with rainwater harvesting as a supplementary source of water and/or seawater pumping and an additional source of energy that is supplied to the system. All different alternatives are evaluated for a 30-year lifespan, and an optimal solution is proposed for each island, based on a life cycle cost (LCC) analysis. The performance of this solution is then assessed under six climate change (CC) scenarios in terms of the rate of on-grid versus off-grid renewable energy that is required in order to achieve a certain reliability level. Overall, the examined scenarios show a decreasing performance in terms of reliability under CC for the eight islands. Full article
(This article belongs to the Special Issue Hydrologic Modelling for Water Resources and River Basin Management)
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Open AccessArticle
Effects of Alternating Irrigation with Fresh and Saline Water on the Soil Salt, Soil Nutrients, and Yield of Tomatoes
Water 2019, 11(8), 1693; https://doi.org/10.3390/w11081693
Received: 1 July 2019 / Revised: 25 July 2019 / Accepted: 13 August 2019 / Published: 15 August 2019
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Abstract
Saline water irrigation has become extremely important in arid and semi-arid areas in northwestern China. To study the effect of alternating irrigation models on the soil nutrients, soil salts, and yield of tomatoes with fresh water (total dissolved solids of 0.50 g·L−1 [...] Read more.
Saline water irrigation has become extremely important in arid and semi-arid areas in northwestern China. To study the effect of alternating irrigation models on the soil nutrients, soil salts, and yield of tomatoes with fresh water (total dissolved solids of 0.50 g·L−1) and saline water (total dissolved solids of 3.01 g·L−1), a two-year field experiment was carried out for tomatoes in the Hetao Irrigation District (HID), containing six drip irrigation models: T1 (all freshwater irrigation), T2 (saline water used in the seedling and flowering stages; fresh water in the fruit-set and breaker stages), T3 (saline water in the flowering and fruit-set stages; fresh water in the seedling and breaker stages), T4 (saline water in the fruit-set and breaker stages; fresh water in the seedling and flowering stages), T5 (saline water in the flowering and breaker stages; fresh water in the seedling and fruit-set stages), T6 (saline water in the seedling and fruit-set stages; fresh water in the flowering and breaker stages). The study found that saline water irrigation tends to have a positive effect on soil total nitrogen and a negative influence on soil total phosphorus at each growth stage of the tomato. Soil Na+, Mg2+, Ca2+, K+, and Cl increased over the growth period, soil HCO3 decreased gradually by growth stage, and the salt ions increased with the amount of saline water applied in alternating irrigation. Though the soil salt accumulated in all experimentally designed alternating irrigation models, soil alkalization did not occur in the tomato root zone under the soil matric potential threshold of −25 kPa. The utilization of saline water resulted in about a 1.9–18.2% decline in fruit yield, but the total soluble solids, lycopene, and sugar in the tomato fruits increased. Ultimately, drip irrigation with fresh water at the seedling to flowering stages and saline water at the fruit-set to breaker stages was suggested for tomato cultivation in HID. Full article
(This article belongs to the Section Water Resources Management and Governance)
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Open AccessArticle
Trophic Features, Benthic Recovery, and Dominance of the Invasive Mytilopsis Sallei in the Yundang Lagoon (Xiamen, China) Following Long-Term Restoration
Water 2019, 11(8), 1692; https://doi.org/10.3390/w11081692
Received: 20 June 2019 / Revised: 5 August 2019 / Accepted: 12 August 2019 / Published: 15 August 2019
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Abstract
A comprehensive set of physicochemical variables in near-bottom water and surface sediments, as well as the soft-bottom macrozoobenthic assemblages were investigated at six sites across the Yundang Lagoon (Southeast China) in November 2012. This lagoon was severely damaged in the 1970s due to [...] Read more.
A comprehensive set of physicochemical variables in near-bottom water and surface sediments, as well as the soft-bottom macrozoobenthic assemblages were investigated at six sites across the Yundang Lagoon (Southeast China) in November 2012. This lagoon was severely damaged in the 1970s due to domestic and industrial pollution and land reclamation and underwent a massive restoration effort over the past 30 years. Our objectives were to: (1) assess the current trophic and environmental condition of the lagoon; (2) investigate the pattern of spatial variation in the macrozoobenthic assemblages; and (3) assess the benthic recovery in relation to the main environmental gradients and the presence of invasive alien species. Nutrient, chlorophyll-a, biological oxygen demand (BOD5), chemical oxygen demand (CODMn), and total organic carbon (TOC) concentrations were lower than those reported in previous decades, yet organically-enriched conditions occurred at an inner site. From azoic conditions in the 1980s and a few benthic species reported prior to this study, we found a significant increase in benthic diversity with 43 species heterogeneously distributed across the lagoon. The invasive bivalve Mytilopsis sallei was the dominant species, which was associated with the richest benthic assemblage. However, M. sallei is a pest species, and its spatiotemporal distribution should be carefully monitored. These results highlight the central role of the macrozoobenthos in providing important ecological information on the current status of the Yundang Lagoon and as an effective biological tool to follow the recovery’s progress and the future evolution of this highly valued ecosystem. Full article
(This article belongs to the Special Issue Ecological Status Assessment of Transitional Waters)
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Open AccessArticle
Applying Cascade-Correlation Neural Networks to In-Fill Gaps in Mediterranean Daily Flow Data Series
Water 2019, 11(8), 1691; https://doi.org/10.3390/w11081691
Received: 26 June 2019 / Revised: 8 August 2019 / Accepted: 10 August 2019 / Published: 15 August 2019
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Abstract
The analyses of water resources availability and impacts are based on the study over time of meteorological and hydrological data trends. In order to perform those analyses properly, long records of continuous and reliable data are needed, but they are seldom available. Lack [...] Read more.
The analyses of water resources availability and impacts are based on the study over time of meteorological and hydrological data trends. In order to perform those analyses properly, long records of continuous and reliable data are needed, but they are seldom available. Lack of records as in gaps or discontinuities in data series and quality issues are two of the main problems more often found in databases used for climate studies and water resources management. Flow data series from gauging stations are not an exception. Over the last 20 years, forecasting models based on artificial neural networks (ANNs) have been increasingly applied in many fields of natural resources, including hydrology. This paper discusses results obtained on the application of cascade-correlation ANN models to predict daily water flow using Julian day and rainfall data provided by nearby weather stations in the Ebro river watershed (Northeast Spain). Five unaltered gauging stations showing a rainfall-dominated hydrological regime were selected for the study. Daily flow and weather data series covered 30 years to encompass the high variability of Mediterranean environments. Models were then applied to the in-filling of existing gaps under different conditions related to the characteristics of the gaps (6 scenarios). Results showed that when short periods before and after the gap are considered, this is a useful approach, although no general rule applied to all stations and gaps investigated. Models for low-water-flow periods provided better results (r = 0.76–0.8). Full article
(This article belongs to the Section Hydrology)
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Open AccessFeature PaperArticle
Relationship between Water Temperature of Polish Rivers and Large-Scale Atmospheric Circulation
Water 2019, 11(8), 1690; https://doi.org/10.3390/w11081690
Received: 30 May 2019 / Revised: 30 July 2019 / Accepted: 12 August 2019 / Published: 15 August 2019
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Abstract
The objective of the paper consisted in determining the effect of macroscale types of NAO, AO, EA, EAWR, SCAND, and AMO atmospheric circulation on changes in water temperature in Polish rivers. The study has made use of a broad body of hydrometeorological materials [...] Read more.
The objective of the paper consisted in determining the effect of macroscale types of NAO, AO, EA, EAWR, SCAND, and AMO atmospheric circulation on changes in water temperature in Polish rivers. The study has made use of a broad body of hydrometeorological materials covering daily water temperature values for 96 water gauge stations located on 53 rivers and air temperature values for 43 meteorological stations. Percentage shares of positive and negative coefficients of correlation of annual, seasonal, and monthly circulation type indices with air and river water temperature were determined, demonstrating the character of teleconnection. Determinations were made of water temperature deviations in positive and negative phases of the analyzed indices from average values from the years 1971–2015, and their statistical significance ascertained. Research has shown that relations between the temperature of river waters in Poland and macroscale circulation types are not strong, however they are noticeable, sometimes even statistically significant, and both temporally and spatially diverse. NAO, AO, EA, and AMO indices are characterized by a generally positive correlation with temperature, whereas SCAND and EWAR indices are characterized by a negative correlation. Research showed a varying impact of types of atmospheric circulation, with their effectiveness increasing in the winter season. The strongest impact on temperature was observed for the positive and negative NAO and AO phases, when deviations of water temperature from average values are correspondingly higher (up to 1.0 °C) and lower (by a maximum of 1.5 °C), and also for the positive and negative SCAND phases, when water temperature are correspondingly lower (by a maximum of 0.8 °C) and higher (by 1.2 °C) than average values. The strongest impact on water temperature in summer, mainly in July, was observed for AMO. The results point to the complexity of processes determining the thermal regime of rivers and to the possibility of additional factors—both regional and local—exerting an influence on their temporal and spatial variability. Full article
(This article belongs to the Special Issue Effects of Oceanic-Atmospheric Oscillations on Rivers)
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Open AccessArticle
Effect of Straw Mulch on Soil Evaporation during Freeze–Thaw Periods
Water 2019, 11(8), 1689; https://doi.org/10.3390/w11081689
Received: 17 July 2019 / Revised: 8 August 2019 / Accepted: 12 August 2019 / Published: 15 August 2019
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Abstract
Reducing soil evaporation is important to alleviate water shortages in arid and semi-arid regions. The objective of this work was to reveal the effect of straw mulch on soil evaporation based on field experiments during a freeze–thaw period in Northern China. Four soil [...] Read more.
Reducing soil evaporation is important to alleviate water shortages in arid and semi-arid regions. The objective of this work was to reveal the effect of straw mulch on soil evaporation based on field experiments during a freeze–thaw period in Northern China. Four soil surface mulch treatment modes were investigated: Bare soil (BS), 1 cm thick straw mulch with 100% coverage rate (J1), 2 cm thick straw mulch with 100% coverage rate (J2), and 2 cm thick straw mulch with 50% coverage rate (J3). Principal component analysis was used to analyze the major factors influencing soil evaporation in three freeze–thaw stages. The results show that cumulative soil evaporation decreased with increased straw mulch thickness and coverage rate. The effect of straw mulching on soil evaporation was obvious during the stable freezing period, and soil evaporation with straw mulch treatments was reduced by 49.0% to 58.8% compared to BS treatment, while there was little difference for straw mulch treatments in the thawing stage. The relationship between cumulative soil evaporation under different straw mulch modes and time was well fitted by the power function. In the unstable freezing stage, the major factors for all treatments influencing soil evaporation were surface soil temperature and water surface evaporation; in the stable stage, they were solar radiation and relative humidity, and in the thawing stage, they were solar radiation and air temperature. The research results can provide a basis for addressing soil water storage and moisture conservation and restraining ineffective soil evaporation in arid and semi-arid areas. Full article
(This article belongs to the Section Water Resources Management and Governance)
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Open AccessArticle
Relationship between Peak Stage, Storm Duration, and Bank Storage along a Meandering Stream
Water 2019, 11(8), 1688; https://doi.org/10.3390/w11081688
Received: 11 July 2019 / Revised: 30 July 2019 / Accepted: 12 August 2019 / Published: 15 August 2019
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Abstract
Groundwater and surface water are often studied as different systems; however, one commonly affects the other. Bank storage, the temporary storage and release of stream water in adjacent aquifers, can contribute a considerable amount of discharge to a river and can be a [...] Read more.
Groundwater and surface water are often studied as different systems; however, one commonly affects the other. Bank storage, the temporary storage and release of stream water in adjacent aquifers, can contribute a considerable amount of discharge to a river and can be a component in the transport and fate of a contaminant. Studies document the effects of increasing stage and increasing storm duration; however, these controls are often investigated separately. This project examined which factor, peak stage or storm duration, was more influential on the bank-storage process. The study focused on a small reach of a third-order, meandering, perennial stream. A 3-D, transient-state numerical model (MODFLOW) was created of the study site, and 36 simulations were run at various peak stages and storm durations. Peak stage and storm durations, while both influential, affected different areas of the bank-storage process. Peak stage was statistically more influential in controlling the maximum volume of bank storage (~3.6×) and the volume of the storage that remained in the system at 100 h (~1.1×). Longer storm duration generated a slower return of water, thus increasing the retention of bank storage. Parafluvial exchange was an important factor in bank storage along a meandering stream, suggesting that at least 2-D, ideally 3-D, models need to be employed in evaluating bank storage. Full article
(This article belongs to the Section Hydrology)
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Open AccessArticle
Physical Modeling of Ski-Jump Spillway to Evaluate Dynamic Pressure
Water 2019, 11(8), 1687; https://doi.org/10.3390/w11081687
Received: 18 June 2019 / Revised: 11 July 2019 / Accepted: 11 July 2019 / Published: 15 August 2019
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Abstract
The effects of changes in the angle of pool impact plate, plunging depth, and discharge upon the dynamic pressure caused by ski-jump buckets were investigated in the laboratory. Four impact plate angles and four plunging depths were used. Discharges of 67, 86, 161, [...] Read more.
The effects of changes in the angle of pool impact plate, plunging depth, and discharge upon the dynamic pressure caused by ski-jump buckets were investigated in the laboratory. Four impact plate angles and four plunging depths were used. Discharges of 67, 86, 161, and 184 L/s were chosen. For any discharge, plunging depth and impact plate angle were regulated, and dynamic pressures were measured by a transducer. The results showed that with the increase in the ratio of drop length of the jet to its break-up length (H/Lb), and with an increase in the impact plate angle, the mean dynamic pressure coefficient decreased. An inspection of the plunging depth (Y) ratio to the initial thickness of the jet (Bj) revealed that when Y/Bj > 3, the plunging depth of the downstream pool reduced dynamic pressure. At the angle of 60°, the dynamic pressure coefficient due to increasing in plunging depth varied from 34% to 95%. Full article
(This article belongs to the Special Issue Environmental Hydraulics Research)
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Open AccessArticle
Red Lentil (Lens culinaris) Extract as a Novel Natural Coagulant for Turbidity Reduction: An Evaluation, Characterization and Performance Optimization Study
Water 2019, 11(8), 1686; https://doi.org/10.3390/w11081686
Received: 30 May 2019 / Revised: 26 June 2019 / Accepted: 8 July 2019 / Published: 14 August 2019
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Abstract
Increasing awareness on the detrimental effects of inorganic chemical coagulants and sustainable treatment have paved the way to develop environmentally-benign natural coagulants for water and wastewater treatment. In this research, brown, green, and red lentil (Lens culinaris) extracts have been evaluated [...] Read more.
Increasing awareness on the detrimental effects of inorganic chemical coagulants and sustainable treatment have paved the way to develop environmentally-benign natural coagulants for water and wastewater treatment. In this research, brown, green, and red lentil (Lens culinaris) extracts have been evaluated as a natural coagulant for the turbidity reduction. The physicochemical characteristics properties of lentil extract were evaluated through field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), zeta potential analysis, and energy-dispersive X-ray (EDX) analysis. Red lentil extract was found to be an anionic polymer with hydroxyl and carboxyl functional groups. The effects of three major operating parameters, pH, the concentration of coagulant, and settling time, were studied and optimized through response surface methodology (RSM) using the Box–Behnken Design (BBD). The red lentil extract as coagulant was outperformed alum in acidic wastewater treatment, which achieved up to 98.87% turbidity removal with an optimum concentration of 26.3 mg/L in 3 min. Besides, the red lentil extract as coagulant reduced 29.42% of material cost, generated 15.6% lower amount of sludge and produced flocs with better settling characteristic (SVI: 7.39) as compared to alum. Based on the experimental observation and characterization study, absorption and bridging mechanisms were proposed for red lentil extract as the coagulant in turbidity reduction. Full article
(This article belongs to the Section Water and Wastewater Treatment)
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