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Water, Volume 9, Issue 6 (June 2017)

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Cover Story Deltas, such as the Mississippi River Delta, are innately dynamic systems and climate change adds a [...] Read more.
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Editorial

Jump to: Research, Review, Other

Open AccessEditorial Advancing Water Footprint Assessment Research: Challenges in Monitoring Progress towards Sustainable Development Goal 6
Water 2017, 9(6), 438; doi:10.3390/w9060438
Received: 31 May 2017 / Revised: 15 June 2017 / Accepted: 17 June 2017 / Published: 19 June 2017
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Abstract
This special issue is a collection of recent papers in the field of Water Footprint Assessment (WFA), an emerging area of research focused on the analysis of freshwater use, scarcity, and pollution in relation to consumption, production, and trade. As increasing freshwater scarcity
[...] Read more.
This special issue is a collection of recent papers in the field of Water Footprint Assessment (WFA), an emerging area of research focused on the analysis of freshwater use, scarcity, and pollution in relation to consumption, production, and trade. As increasing freshwater scarcity forms a major risk to the global economy, sustainable management of water resources is a prerequisite to development. We introduce the papers in this special issue by relating them to Sustainable Development Goal (SDG) number 6 of the United Nations, the goal on water. We will particularly articulate how each paper drives the understanding needed to achieve target 6.3 on water quality and pollution and target 6.4 on water-use efficiency and water scarcity. Regarding SDG 6, we conclude that it lacks any target on using green water more efficiently, and while addressing efficiency and sustainability of water use, it lacks a target on equitable sharing of water. The latter issue is receiving limited attention in research as well. By primarily focusing on water-use efficiency in farming and industries at the local level, to a lesser extent to using water sustainably at the level of total water systems (like drainage basins, aquifers), and largely ignoring issues around equitable water use, understanding of our water problems and proposed solutions will likely remain unbalanced. Full article
(This article belongs to the Special Issue Water Footprint Assessment)
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Open AccessFeature PaperEditorial Constructed Wetlands for Water Treatment: New Developments
Water 2017, 9(6), 397; doi:10.3390/w9060397
Received: 24 April 2017 / Revised: 16 May 2017 / Accepted: 31 May 2017 / Published: 2 June 2017
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Abstract
Constructed wetlands (CWs) are currently regarded as established eco-technologies to treat water pollution. Although considered near-natural systems, they are totally engineered solutions for which research has been actively developed over the past decades. This paper provides a brief meta-analysis on the latest scientific
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Constructed wetlands (CWs) are currently regarded as established eco-technologies to treat water pollution. Although considered near-natural systems, they are totally engineered solutions for which research has been actively developed over the past decades. This paper provides a brief meta-analysis on the latest scientific publications in the field and an overview of the special issue focused on the new developments in the use of CWs for water treatment. The selected papers cover a wide range of relevant developments in the field, including the use of different CW system designs, the capacity to treat different types of pollutants, and studies aiming at getting a better understanding of the treatment processes in CWs. Full article
(This article belongs to the Special Issue Constructed Wetlands for Water Treatment: New Developments)

Research

Jump to: Editorial, Review, Other

Open AccessArticle Modelling of Violent Water Wave Propagation and Impact by Incompressible SPH with First-Order Consistent Kernel Interpolation Scheme
Water 2017, 9(6), 400; doi:10.3390/w9060400
Received: 30 April 2017 / Revised: 27 May 2017 / Accepted: 31 May 2017 / Published: 4 June 2017
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Abstract
The Smoothed Particle Hydrodynamics (SPH) method has proven to have great potential in dealing with the wave–structure interactions since it can deal with the large amplitude and breaking waves and easily captures the free surface. The paper will adopt an incompressible SPH (ISPH)
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The Smoothed Particle Hydrodynamics (SPH) method has proven to have great potential in dealing with the wave–structure interactions since it can deal with the large amplitude and breaking waves and easily captures the free surface. The paper will adopt an incompressible SPH (ISPH) approach to simulate the wave propagation and impact, in which the fluid pressure is solved using a pressure Poisson equation and thus more stable and accurate pressure fields can be obtained. The focus of the study is on comparing three different pressure gradient calculation models in SPH and proposing the most efficient first-order consistent kernel interpolation (C1_KI) numerical scheme for modelling violent wave impact. The improvement of the model is validated by the benchmark dam break flows and laboratory wave propagation and impact experiments. Full article
(This article belongs to the Special Issue Modeling of Water Systems)
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Open AccessFeature PaperArticle Role of Perturbing Ocean Initial Condition in Simulated Regional Sea Level Change
Water 2017, 9(6), 401; doi:10.3390/w9060401
Received: 28 April 2017 / Revised: 27 May 2017 / Accepted: 31 May 2017 / Published: 5 June 2017
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Abstract
Multiple lines of observational evidence indicate that the global climate has been getting warmer since the early 20th century. This warmer climate has led to a global mean sea level rise of about 18 cm during the 20th century, and over 6 cm
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Multiple lines of observational evidence indicate that the global climate has been getting warmer since the early 20th century. This warmer climate has led to a global mean sea level rise of about 18 cm during the 20th century, and over 6 cm for the first 15 years of the 21st century. Regionally the sea level rise is not uniform due in large part to internal climate variability. To better serve the community, the uncertainties of predicting/projecting regional sea level changes associated with internal climate variability need to be quantified. Previous research on this topic has used single-model large ensembles with perturbed atmospheric initial conditions (ICs). Here we compare uncertainties associated with perturbing ICs in just the atmosphere and just the ocean using a state-of-the-art coupled climate model. We find that by perturbing the oceanic ICs, the uncertainties in regional sea level changes increase compared to those with perturbed atmospheric ICs. Thus, in order for us to better assess the full spectrum of the impacts of such internal climate variability on regional and global sea level rise, approaches that involve perturbing both atmospheric and oceanic initial conditions are necessary. Full article
(This article belongs to the Special Issue Sea Level Changes)
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Open AccessArticle Interannual and Decadal Variability in Tropical Pacific Sea Level
Water 2017, 9(6), 402; doi:10.3390/w9060402
Received: 29 April 2017 / Revised: 30 May 2017 / Accepted: 2 June 2017 / Published: 5 June 2017
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Abstract
A notable feature in the first 20-year satellite altimetry records is an anomalously fast sea level rise (SLR) in the western Pacific impacting island nations in this region. This observed trend is due to a combination of internal variability and external forcing. The
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A notable feature in the first 20-year satellite altimetry records is an anomalously fast sea level rise (SLR) in the western Pacific impacting island nations in this region. This observed trend is due to a combination of internal variability and external forcing. The dominant mode of dynamic sea level (DSL) variability in the tropical Pacific presents as an east-west see-saw pattern. To assess model skill in simulating this variability mode, we compare 38 Coupled Model Intercomparison Project Phase 5 (CMIP5) models with 23-year satellite data, 55-year reanalysis products, and 60–year sea level reconstruction. We find that models underestimate variance in the Pacific sea level see-saw, especially at decadal, and longer, time scales. The interannual underestimation is likely due to a relatively low variability in the tropical zonal wind stress. Decadal sea level variability may be influenced by additional factors, such as wind stress at higher latitudes, subtropical gyre position and strength, and eddy heat transport. The interannual variability of the Niño 3.4 index is better represented in CMIP5 models despite low tropical Pacific wind stress variability. However, as with sea level, variability in the Niño 3.4 index is underestimated on decadal time scales. Our results show that DSL should be considered, in addition to sea surface temperature (SST), when evaluating model performance in capturing Pacific variability, as it is directly related to heat content in the ocean column. Full article
(This article belongs to the Special Issue Sea Level Changes)
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Open AccessArticle Gridded Snow Water Equivalent Reconstruction for Utah Using Forest Inventory and Analysis Tree-Ring Data
Water 2017, 9(6), 403; doi:10.3390/w9060403
Received: 10 March 2017 / Revised: 23 May 2017 / Accepted: 30 May 2017 / Published: 6 June 2017
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Abstract
Snowpack observations in the Intermountain West are sparse and short, making them difficult for use in depicting past variability and extremes. This study presents a reconstruction of April 1 snow water equivalent (SWE) for the period of 1850–1989 using increment cores collected by
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Snowpack observations in the Intermountain West are sparse and short, making them difficult for use in depicting past variability and extremes. This study presents a reconstruction of April 1 snow water equivalent (SWE) for the period of 1850–1989 using increment cores collected by the U.S. Forest Service, Interior West Forest Inventory and Analysis program (FIA). In the state of Utah, SWE was reconstructed for 38 snow course locations using a combination of standardized tree-ring indices derived from both FIA increment cores and publicly available tree-ring chronologies. These individual reconstructions were then interpolated to a 4-km grid using an objective analysis with elevation correction to create an SWE product. The results showed a significant correlation with observed SWE as well as good correspondence to regional tree-ring-based drought reconstructions. Diagnostic analysis showed statewide coherent climate variability on inter-annual and inter-decadal time-scales, with added geographical details that would not be possible using courser pre-instrumental proxy datasets. This SWE reconstruction provides water resource managers and forecasters with better spatial resolution to examine past variability in snowpack, which will be important as future hydroclimatic variability is amplified by climate change. Full article
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Open AccessArticle Canopy Transpiration and Stomatal Responses to Prolonged Drought by a Dominant Desert Species in Central Asia
Water 2017, 9(6), 404; doi:10.3390/w9060404
Received: 11 April 2017 / Revised: 25 May 2017 / Accepted: 2 June 2017 / Published: 6 June 2017
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Abstract
In arid and semiarid lands, canopy transpiration and its dynamics depend largely on stomatal sensitivity to drought. In this study, the sap flow of a dominant species, Haloxylon ammodendron growing in Central Asian deserts, was monitored using Granier-type sensors, from which the canopy
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In arid and semiarid lands, canopy transpiration and its dynamics depend largely on stomatal sensitivity to drought. In this study, the sap flow of a dominant species, Haloxylon ammodendron growing in Central Asian deserts, was monitored using Granier-type sensors, from which the canopy stomatal conductance was derived. The responses of canopy transpiration and stomatal conductance to environmental variables during the second half of the growing season, when annual prolonged drought occurred, was analyzed for four continuous years, from 2013 to 2016. A soil water content (SWC) of 3% was identified as the lower soil water threshold for this species, below which the plant lost the ability for stomatal regulation on water loss and suffered the risk of mortality. Above this threshold, the sensitivity of canopy transpiration to vapor pressure deficit, VPD (K), was linearly correlated with SWC, which mainly resulted from different stomatal behaviors at varying drought intensities. Stomatal sensitivity to VPD (m/Gsref) increased linearly with soil moisture deficit, inducing a shift from more anisohydric to a more isohydric stomatal behavior. The flexibility of stomatal behavior regarding soil drought was one key element facilitating the survival of H. ammodendron in such an extreme dry environment. Full article
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Open AccessArticle Streamflow Forecasting Using Empirical Wavelet Transform and Artificial Neural Networks
Water 2017, 9(6), 406; doi:10.3390/w9060406
Received: 13 April 2017 / Revised: 31 May 2017 / Accepted: 2 June 2017 / Published: 7 June 2017
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Abstract
Accurate and reliable streamflow forecasting plays an important role in various aspects of water resources management such as reservoir scheduling and water supply. This paper shows the development of a novel hybrid model for streamflow forecasting and demonstrates its efficiency. In the proposed
[...] Read more.
Accurate and reliable streamflow forecasting plays an important role in various aspects of water resources management such as reservoir scheduling and water supply. This paper shows the development of a novel hybrid model for streamflow forecasting and demonstrates its efficiency. In the proposed hybrid model for streamflow forecasting, the empirical wavelet transform (EWT) is firstly employed to eliminate the redundant noises from the original streamflow series. Secondly, the partial autocorrelation function (PACF) values are explored to identify the inputs for the artificial neural network (ANN) models. Thirdly, the weights and biases of the ANN architecture are tuned and optimized by the multi-verse optimizer (MVO) algorithm. Finally, the simulated streamflow is obtained using the well-trained MVO-ANN model. The proposed hybrid model has been applied to annual streamflow observations from four hydrological stations in the upper reaches of the Yangtze River, China. Parallel experiments using non-denoising models, the back propagation neural network (BPNN) and the ANN optimized by the particle swarm optimization algorithm (PSO-ANN) have been designed and conducted to compare with the proposed model. Results obtained from this study indicate that the proposed hybrid model can capture the nonlinear characteristics of the streamflow time series and thus provides more accurate forecasting results. Full article
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Open AccessArticle Evaluation of Double Perforated Baffles Installed in Rectangular Secondary Clarifiers
Water 2017, 9(6), 407; doi:10.3390/w9060407
Received: 1 May 2017 / Revised: 4 June 2017 / Accepted: 6 June 2017 / Published: 7 June 2017
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Abstract
Double perforated baffles in rectangular secondary clarifiers were studied to determine whether they contribute to producing high-quality effluents. The Computational Fluid Dynamics (CFD) simulations indicated that bio-flocculation occurred at the front of the baffle and the longitudinal movement of the settled sludge was
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Double perforated baffles in rectangular secondary clarifiers were studied to determine whether they contribute to producing high-quality effluents. The Computational Fluid Dynamics (CFD) simulations indicated that bio-flocculation occurred at the front of the baffle and the longitudinal movement of the settled sludge was hampered whenever the clarifier had high inflow. Simulation results showed that the rectangular clarifier with the double perforated baffle produced an effluent with lower suspended solid (SS) concentrations than the effluent from the clarifier without the baffle. To verify the simulation results, a double perforated baffle was installed in two of the 48 rectangular clarifiers in a 300,000 m3/d-capacity wastewater treatment plant. To study the effect of the baffle on solid removal, the effluent turbidity of the clarifier with and without the double perforated baffle was measured simultaneously. Experimental data showed that the double perforated baffle played a significant role in reducing effluent turbidity. The effluent turbidity reduction ratio with the baffle decreased when the Sludge Volume Index (SVI) of the Mixed Liquor Suspended Solids (MLSS) was below 100 mL/g. The overall average reduction ratio was 24.3% for SVI < 100 mL/g and 45.1% for SVI > 100 mL/g. The results of this study suggest that double perforated baffles must be installed in secondary rectangular clarifiers to produce high-quality effluent regardless of the operational conditions. Full article
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Open AccessArticle Perceptions and Acceptance of Desalinated Seawater for Irrigation: A Case Study in the Níjar District (Southeast Spain)
Water 2017, 9(6), 408; doi:10.3390/w9060408
Received: 12 May 2017 / Revised: 5 June 2017 / Accepted: 6 June 2017 / Published: 8 June 2017
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Abstract
In the context of increasing demand for irrigation water—but, at the same time, with the constraints in the supply from traditional resources—desalinated seawater has been recognized as one of the alternative sources of water to increase the supply for agricultural irrigation. However, its
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In the context of increasing demand for irrigation water—but, at the same time, with the constraints in the supply from traditional resources—desalinated seawater has been recognized as one of the alternative sources of water to increase the supply for agricultural irrigation. However, its use among farmers has not yet started to expand. Policy makers need to understand what is causing the low acceptance levels of farmers, and how their attitudes could be improved. This is the first study that has conducted an analysis of farmers’ perceptions and acceptance of the use of desalinated seawater for irrigation. The study is based on collected data from a survey completed by farmers in southeastern Spain who do not use desalinated seawater. The main results indicate that desalinated seawater as a water supply source has the lowest acceptance level for farmers. Barriers for its use are price, the need for additional fertilization, and the perception that it would negatively affect the yield and crop quality. The farmers’ general level of knowledge about the impact of using desalinated seawater in agriculture is extremely low. Furthermore, farmers consider it a priority that their startup investment should be subsidized and that water prices should be reduced. Based on the study findings, this paper makes recommendations for the decision-making process in order to improve farmers’ acceptance levels. Full article
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Open AccessArticle Characteristics and Biodegradability of Wastewater Organic Matter in Municipal Wastewater Treatment Plants Collecting Domestic Wastewater and Industrial Discharge
Water 2017, 9(6), 409; doi:10.3390/w9060409
Received: 7 April 2017 / Revised: 8 May 2017 / Accepted: 2 June 2017 / Published: 8 June 2017
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Abstract
Municipal wastewater treatment plants (WWTPs) in Korea collect and treat not only domestic wastewater, but also discharge from industrial complexes. However, some industrial discharges contain a large amount of non-biodegradable organic matter, which cannot be treated properly in a conventional biological WWTP. This
[...] Read more.
Municipal wastewater treatment plants (WWTPs) in Korea collect and treat not only domestic wastewater, but also discharge from industrial complexes. However, some industrial discharges contain a large amount of non-biodegradable organic matter, which cannot be treated properly in a conventional biological WWTP. This study aimed to investigate the characteristics and biodegradability of the wastewater organic matter contained in the industrial discharges and to examine the fate of the industrial discharges in a biological WWTP. In contrast to most previous studies targeting a specific group of organic compounds or traditional water quality indices, such as biological oxygen demand (BOD) and chemical oxygen demand (COD), this study was purposed to quantify and characterize the biodegradable and nonbiodegradable fractions of the wastewater organic matter. Chemical oxygen demand (COD) fractionation tests and fluorescence spectroscopy revealed that the industrial discharge from dyeing or pulp mill factories contained more non-biodegradable soluble organic matter than did the domestic wastewater. Statistical analysis on the WWTPs’ monitoring data indicated that the industrial discharge containing non-biodegradable soluble organic matter was not treated effectively in a biological WWTP, but was escaping from the system. Thus, industrial discharge that contained non-biodegradable soluble organic matter was a major factor in the decrease in biodegradability of the discharge, affecting the ultimate fate of wastewater organic matter in a biological WWTP. Further application of COD fractionation and fluorescence spectroscopy to wastewaters, with various industrial discharges, will help scientists and engineers to better design and operate a biological WWTP, by understanding the fate of wastewater organic matter. Full article
(This article belongs to the Special Issue Biological Treatment of Wastewater)
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Open AccessArticle Current Assessment and Future Outlook for Water Resources Considering Climate Change and a Population Burst: A Case Study of Ciliwung River, Jakarta City, Indonesia
Water 2017, 9(6), 410; doi:10.3390/w9060410
Received: 6 April 2017 / Revised: 27 May 2017 / Accepted: 5 June 2017 / Published: 8 June 2017
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Abstract
Modeling insecurity under future climate change and socio-economic development is indispensable for adaptive planning and sustainable management of water resources. This case study strives to assess the water quality and quantity status for both the present and the near future in the Ciliwung
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Modeling insecurity under future climate change and socio-economic development is indispensable for adaptive planning and sustainable management of water resources. This case study strives to assess the water quality and quantity status for both the present and the near future in the Ciliwung River basin inside the Jakarta Province under different scenarios using population growth with planned additional wastewater management infrastructure by 2030 as mentioned in the local master plan, and comparing the above conditions with the addition of the effects of climate change. Biochemical oxygen demand (BOD), chemical oxygen demand (COD) and nitrate (NO3), the three important indicators of aquatic ecosystem health, were simulated to assess river pollution. Simulation results suggest that water quality in year 2030 will further deteriorate compared to the base year 2000 due to population growth and climate change, even considering the planned wastewater management infrastructure. The magnitude of impact from population growth is far greater than that from climate change. Simulated values of NO3, BOD and COD ranged from 6.07 to 13.34 mg/L, 7.65 to 11.41 mg/L, and 20.16 to 51.01 mg/L, respectively. Almost all of the water quality parameters exceeded the safe limit suitable for a healthy aquatic system, especially for the year 2030. The situation of water quality is worse for the downstream sampling location because of the cumulative effect of transport of untreated pollutants coming from upstream, as well as local dumping. This result will be useful for local policy makers and stakeholders involved in the water sector to formulate strategic and adaptive policies and plan for the future. One of the potential policy interventions is to implement a national integrated sewerage and septage management program on a priority basis, considering various factors like population density and growth, and global changes for both short- and long-term measures. Full article
(This article belongs to the Special Issue Adaptation Strategies to Climate Change Impacts on Water Resources)
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Open AccessFeature PaperArticle Improvement to the Huff Curve for Design Storms and Urban Flooding Simulations in Guangzhou, China
Water 2017, 9(6), 411; doi:10.3390/w9060411
Received: 24 March 2017 / Revised: 9 May 2017 / Accepted: 5 June 2017 / Published: 8 June 2017
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Abstract
The storm hyetograph is critical in drainage design since it determines the peak flooding volume in a catchment and the corresponding drainage capacity demand for a return period. This study firstly compares the common design storms such as the Chicago, Huff, and Triangular
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The storm hyetograph is critical in drainage design since it determines the peak flooding volume in a catchment and the corresponding drainage capacity demand for a return period. This study firstly compares the common design storms such as the Chicago, Huff, and Triangular curves employed to represent the storm hyetographs in the metropolitan area of Guangzhou using minute-interval rainfall data during 2008–2012. These common design storms cannot satisfactorily represent the storm hyetographs in sub-tropic areas of Guangzhou. The normalized time of peak rainfall is at 33 ± 5% for all storms in the Tianhe and Panyu districts, and most storms (84%) are in the 1st and 2nd quartiles. The Huff curves are further improved by separately describing the rising and falling limbs instead of classifying all storms into four quartiles. The optimal time intervals are 1–5 min for deriving a practical urban design storm, especially for short-duration and intense storms in Guangzhou. Compared to the 71 observed storm hyetographs, the Improved Huff curves have smaller RMSE and higher NSE values (6.43, 0.66) than those of the original Huff (6.62, 0.63), Triangular (7.38, 0.55), and Chicago (7.57, 0.54) curves. The mean relative difference of peak flooding volume simulated with SWMM using the Improved Huff curve as the input is only 2%, −6%, and 8% of those simulated by observed rainfall at the three catchments, respectively. In contrast, those simulated by the original Huff (−12%, −43%, −16%), Triangular (−22%, −62%, −38%), and Chicago curves (−17%, −19%, −21%) are much smaller and greatly underestimate the peak flooding volume. The Improved Huff curve has great potential in storm water management such as flooding risk mapping and drainage facility design, after further validation. Full article
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Open AccessFeature PaperArticle Treatment of Oily Wastewater with Membrane Bioreactor Systems
Water 2017, 9(6), 412; doi:10.3390/w9060412
Received: 6 April 2017 / Revised: 5 June 2017 / Accepted: 6 June 2017 / Published: 9 June 2017
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Abstract
The aim of the present work was to investigate the behavior of a membrane bioreactor (MBR) system for the treatment of oily wastewater. A bench scale MBR was fed with synthetic wastewater containing diesel fuel. Organic carbon, hydrocarbon and ammonium removal, kinetic constants,
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The aim of the present work was to investigate the behavior of a membrane bioreactor (MBR) system for the treatment of oily wastewater. A bench scale MBR was fed with synthetic wastewater containing diesel fuel. Organic carbon, hydrocarbon and ammonium removal, kinetic constants, extracellular polymeric substances production, and membrane fouling rates were monitored. The MBR plant was operated for more than 200 days, and the results highlighted good carbon removal and nitrification, suggesting a sort of biomass adaptation to hydrocarbons. Membrane fouling analysis showed an increase in total resistance, likely due to hydrocarbons, which caused an irreversible fouling (pore blocking) mainly due to oil deposition. Full article
(This article belongs to the Special Issue Oily Water Treatment)
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Open AccessArticle System Reliability Evaluation in Water Distribution Networks with the Impact of Valves Experiencing Cascading Failures
Water 2017, 9(6), 413; doi:10.3390/w9060413
Received: 31 March 2017 / Revised: 8 May 2017 / Accepted: 5 June 2017 / Published: 9 June 2017
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Abstract
Water distribution networks (WDNs) represent a class of critical infrastructure networks. When a disaster occurs, component failures in a WDN may trigger system failures that result in larger-scale reactions. The aim of the paper is to evaluate the evolution of system reliability and
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Water distribution networks (WDNs) represent a class of critical infrastructure networks. When a disaster occurs, component failures in a WDN may trigger system failures that result in larger-scale reactions. The aim of the paper is to evaluate the evolution of system reliability and failure propagation time for a WDN experiencing cascading failures, and find the critical pipes which may reduce system reliability dramatically. Multiple factors are considered in the method such as network topology, the balance of water supply and demand, demand multiplier, and pipe break isolation. The pipe-based attack with multiple failure scenarios is simulated in the paper. A case WDN is used to illustrate the method. The results show that the lowest capacity gets stronger when a WDN is short of supply, becoming the dominant factor that decides the evolution of system reliability and failure propagation time. The valve ratio (VR) and system reliability present a flattened S curve relationship, and there are two turning points in VR. The critical pipes can be identified. With the fixed 5% valves, a WDN can improve system reliability and resist cascading failures effectively. The findings provide insights into the system reliability and failure propagation time for WDNs experiencing cascading failures. It is proven to be useful in future studies focused on the operation and management of water services. Full article
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Open AccessArticle Inexact Two-Stage Stochastic Programming for Water Resources Allocation under Considering Demand Uncertainties and Response—A Case Study of Tianjin, China
Water 2017, 9(6), 414; doi:10.3390/w9060414
Received: 25 April 2017 / Revised: 25 May 2017 / Accepted: 2 June 2017 / Published: 9 June 2017
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Abstract
In this paper, an inexact two-stage stochastic programming model was developed for supporting regional water resource allocation management under uncertainties. The proposed model is an integrated framework of interval parameter programming and two-stage stochastic programming, which can tackle uncertain parameters expressed as interval
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In this paper, an inexact two-stage stochastic programming model was developed for supporting regional water resource allocation management under uncertainties. The proposed model is an integrated framework of interval parameter programming and two-stage stochastic programming, which can tackle uncertain parameters expressed as interval values with probability distribution information. The proposed model was successfully applied to a typical heavy industrial city suffering water shortage in the east of China, Tianjin. The uncertainties of future water demand were taken into account through generating a set of representative scenarios. The results indicated that different scenarios would affect the water distribution patterns, water shortages, total benefits and system cost. The results revealed that the transferred water from Luan River and Changjiang River would still be the main water resource for each water user. Besides, nearly all water demand in planning horizon would be guaranteed through the reasonable dispatch except under high demand level scenario, in which a small proportion of water requirement in agricultural, municipal and environmental sectors would not be satisfied. The developed method could be used by environmental managers to identify the optimal water supply plan from multiple sources to different end-user sectors under system uncertainties. Full article
(This article belongs to the Special Issue Modeling of Water Systems)
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Open AccessArticle Sources and Dynamics of Dissolved Inorganic Carbon, Nitrogen, and Phosphorus in a Large Agricultural River Basin in Arid Northwestern China
Water 2017, 9(6), 415; doi:10.3390/w9060415
Received: 9 March 2017 / Revised: 5 June 2017 / Accepted: 5 June 2017 / Published: 9 June 2017
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Abstract
The present study assessed the export of inorganic carbon, nitrogen, and phosphorus within a large agricultural basin in arid northwestern China. Groundwater of various depths and river water along a 160 km reach were sampled during contrasting flow conditions. Dissolved inorganic carbon (DIC)
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The present study assessed the export of inorganic carbon, nitrogen, and phosphorus within a large agricultural basin in arid northwestern China. Groundwater of various depths and river water along a 160 km reach were sampled during contrasting flow conditions. Dissolved inorganic carbon (DIC) concentrations and δ13C-DIC values indicate that lithogenic carbonate weathering was the main source of DIC in the basin. Discharge played an important role in regulating the amount and flowpath of nutrients mobilized from soils to the river. Ammonium was mobilized mostly by storm flows whereas the other nutrients were exported through both storm and groundwater flows. Hydrological events, occurring on only about 10% of the days for a year, were responsible for more than 40% of annual nutrient exports. Shallow groundwater was an important source of DIC and nitrate in river water within the alluvial plain, where groundwater discharges regulated their longitudinal variability along the river. According to a mixing model using δ13C-DIC and chloride, groundwater comprised 9–34% and 39–60% of river water at high discharge and baseflow, respectively. Together, our data highlight the importance of reducing storm runoffs and monitoring nutrient pollution within this large basin. Full article
(This article belongs to the Special Issue Sustainable Water Management within Inland River Watershed)
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Open AccessFeature PaperArticle Allelopathy Inhibitory Effects of Hydrodictyon reticulatum on Chlorella pyrenoidosa under Co-Culture and Liquor-Cultured Conditions
Water 2017, 9(6), 416; doi:10.3390/w9060416
Received: 8 March 2017 / Revised: 26 May 2017 / Accepted: 7 June 2017 / Published: 9 June 2017
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Abstract
Eutrophication has become increasingly serious in recent years, which severely impairs the aquatic ecosystem. Applying environmentally-friendly methods to effectively control the growth of algae and avoid eutrophication has been proved to be a promising way. Thus, the potential of Hydrodictyon reticulatum on eutrophication
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Eutrophication has become increasingly serious in recent years, which severely impairs the aquatic ecosystem. Applying environmentally-friendly methods to effectively control the growth of algae and avoid eutrophication has been proved to be a promising way. Thus, the potential of Hydrodictyon reticulatum on eutrophication control was studied in this research. The allelopathy inhibitory effects of H. reticulatum on the growth of Chlorella pyrenoidosa were investigated under both co-culture and liquor-cultured conditions. The biomass and chlorophyll a content of C. pyrenoidosa were determined with time during the experimental period. Nitrogen and phosphorus removal capacities of H. reticulatum were also examined. Results showed that the growth of C. pyrenoidosa was obviously inhibited under both co-culture and liquor-cultured conditions, and the “Hormesis effect” was patently observed. The strength of allelopathy inhibitory effect depended on the relative biomass between H. reticulatum and C. pyrenoidosa. The allelopathy inhibitory effect of H. reticulatum on C. pyrenoidosa under co-culture condition was stronger than that under liquor-cultured condition. The decrease speeds of nitrogen and phosphorus concentrations were in direct proportion to the concentration of H. reticulatum. Full article
(This article belongs to the Special Issue Modeling of Water Systems)
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Open AccessArticle Probabilistic Models for the Peak Residential Water Demand
Water 2017, 9(6), 417; doi:10.3390/w9060417
Received: 31 December 2016 / Revised: 5 June 2017 / Accepted: 7 June 2017 / Published: 10 June 2017
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Abstract
Peak water demand is one of the most stringent operative conditions for a Water Distribution System (WDS), not only for the intensity of the event itself, but also for its recurring nature. The estimation of the maximum water demand is a crucial aspect
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Peak water demand is one of the most stringent operative conditions for a Water Distribution System (WDS), not only for the intensity of the event itself, but also for its recurring nature. The estimation of the maximum water demand is a crucial aspect in both the design and management processes. Studies in the past have tackled this issue with deterministic approaches, even if peak phenomena are distinctly random. In this work, probabilistic models have been developed to study and forecast the daily maximum residential water demand. Some probability distributions have been tested by means of statistical inferences on different data samples related to three monitored WDS. The parameter estimations of the proposed equations have been related to the number of supplied users. Furthermore, this work investigates time scaling effects on the effectiveness of the proposed distributions and relations. Corrective factors that take into account the effect of time averaging step on the above-mentioned parameters have been proposed. Full article
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Open AccessArticle Using Modeling Tools to Better Understand Permafrost Hydrology
Water 2017, 9(6), 418; doi:10.3390/w9060418
Received: 27 April 2017 / Revised: 23 May 2017 / Accepted: 26 May 2017 / Published: 10 June 2017
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Abstract
Modification of the hydrological cycle and, subsequently, of other global cycles is expected in Arctic watersheds owing to global change. Future climate scenarios imply widespread permafrost degradation caused by an increase in air temperature, and the expected effect on permafrost hydrology is immense.
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Modification of the hydrological cycle and, subsequently, of other global cycles is expected in Arctic watersheds owing to global change. Future climate scenarios imply widespread permafrost degradation caused by an increase in air temperature, and the expected effect on permafrost hydrology is immense. This study aims at analyzing, and quantifying the daily water transfer in the largest Arctic river system, the Yenisei River in central Siberia, Russia, partially underlain by permafrost. The semi-distributed SWAT (Soil and Water Assessment Tool) hydrological model has been calibrated and validated at a daily time step in historical discharge simulations for the 2003–2014 period. The model parameters have been adjusted to embrace the hydrological features of permafrost. SWAT is shown capable to estimate water fluxes at a daily time step, especially during unfrozen periods, once are considered specific climatic and soils conditions adapted to a permafrost watershed. The model simulates average annual contribution to runoff of 263 millimeters per year (mm yr−1) distributed as 152 mm yr−1 (58%) of surface runoff, 103 mm yr−1 (39%) of lateral flow and 8 mm yr−1 (3%) of return flow from the aquifer. These results are integrated on a reduced basin area downstream from large dams and are closer to observations than previous modeling exercises. Full article
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Open AccessArticle Impact of Institutional Change on Irrigation Management: A Case Study from Southern Uzbekistan
Water 2017, 9(6), 419; doi:10.3390/w9060419
Received: 6 April 2017 / Revised: 30 May 2017 / Accepted: 6 June 2017 / Published: 10 June 2017
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Abstract
The rapidly growing population in Uzbekistan has put massive pressure on limited water resources, resulting in frequent water shortages. Irrigation is by far the major water use. Improving irrigation water use through the institutional change of establishing water consumer associations (WCAs) has been
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The rapidly growing population in Uzbekistan has put massive pressure on limited water resources, resulting in frequent water shortages. Irrigation is by far the major water use. Improving irrigation water use through the institutional change of establishing water consumer associations (WCAs) has been identified as a way to increase agricultural production and meet the food demand in the area. However, most WCAs are not fully able to organize collective action or generate sufficient funds to carry out their responsibilities. This study investigated the water-resource-related challenges faced by WCAs and local farmers in Kashkadarya Province in Uzbekistan, using semi-structured expert interviews and focus group discussions. The resulting data were analyzed using qualitative analysis software (Atlas.ti). The results indicated that outdated infrastructure, poor governance, and farmers’ non-payment of irrigation service fees hamper sustainable water management. Greater trust and communication within the WCAs would make an important contribution to effective collective action and to the long-term sustainability of local associations. Full article
(This article belongs to the Special Issue The Future of Water Management in Central Asia)
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Open AccessArticle Characterising Bedrock Aquifer Systems in Korea Using Paired Water-Level Monitoring Data
Water 2017, 9(6), 420; doi:10.3390/w9060420
Received: 5 March 2017 / Revised: 1 June 2017 / Accepted: 7 June 2017 / Published: 10 June 2017
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Abstract
This study focused on characterising aquifer systems based on water-level changes observed systematically at 159 paired groundwater monitoring wells throughout Korea. Using spectral analysis, principal component analysis (PCA), and cross-correlation analysis with linear regression, aquifer conditions were identified from the comparison of water-level
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This study focused on characterising aquifer systems based on water-level changes observed systematically at 159 paired groundwater monitoring wells throughout Korea. Using spectral analysis, principal component analysis (PCA), and cross-correlation analysis with linear regression, aquifer conditions were identified from the comparison of water-level changes in shallow alluvial and deep bedrock monitoring wells. The spectral analysis could identify the aquifer conditions (i.e., unconfined, semi-confined and confined) of 58.5% of bedrock wells and 42.8% of alluvial wells: 93 and 68 wells out of 159 wells, respectively. Even among the bedrock wells, 50 wells (53.7%) exhibited characteristics of the unconfined condition, implying significant vulnerability of the aquifer to contaminants from the land surface and shallow depths. It appears to be better approach for deep bedrock aquifers than shallow alluvial aquifers. However, significant portions of the water-level changes remained unclear for categorising aquifer conditions due to disturbances in data continuity. For different aquifer conditions, PCA could show typical pattern and factor scores of principal components. Principal component 1 due to wet-and-dry seasonal changes and water-level response time was dominant covering about 55% of total variances of each aquifer conditions, implying the usefulness of supplementary method of aquifer characterisation. Cross-correlation and time-lag analysis in the water-level responses to precipitations clearly show how the water levels in shallow and deep wells correspond in time scale. No significant differences in time-lags was found between shallow and deep wells. However, clear time-lags were found to be increasing from unconfined to confined conditions: from 1.47 to 2.75 days and from 1.78 to 2.75 days for both shallow alluvial and deep bedrock wells, respectively. In combination of various statistical methods, three types of water-level fluctuation patterns were identified from the water-level pairs: Type I of identical aquifer systems (77.8%), Type II of the different aquifer systems with different recharge flow paths (9.5%), and Type III of unmatched aquifer system pairs and correlations (12.7%). Type I and II could be used as verification of aquifer condition in the paired monitoring system. However, Type III shows the complexity of water-level fluctuation in different aquifer conditions. This study showed that confined or not-confined conditions are not directly related to the depth of wells in the aquifer. Therefore, the utilisation of groundwater as a water-supply source should be carefully designed, tested for its hydrogeologic conditions, and managed to ensure sustainable quantity and quality. Full article
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Open AccessArticle Successes of Restoration and Its Effect on the Fish Community in a Freshwater Tidal Embayment of the Potomac River, USA
Water 2017, 9(6), 421; doi:10.3390/w9060421
Received: 10 April 2017 / Revised: 8 June 2017 / Accepted: 9 June 2017 / Published: 11 June 2017
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Abstract
After a local wastewater treatment plant significantly reduced phosphorus loading into a phytoplankton-dominated tributary of the Potomac River in the early 1980s, water quality and biological communities were monitored bi-weekly from April to September. After a 10-year time-lag, submerged aquatic vegetation (SAV), once
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After a local wastewater treatment plant significantly reduced phosphorus loading into a phytoplankton-dominated tributary of the Potomac River in the early 1980s, water quality and biological communities were monitored bi-weekly from April to September. After a 10-year time-lag, submerged aquatic vegetation (SAV), once abundant in this freshwater tidal embayment, returned to the area in 1993. After additional reductions in nitrogen load starting in 2000, the system switched to an SAV-dominated state in 2005. Fish abundance did not change during these distinct phase changes, but the fish community structure did. Increases in SAV provided refuge and additional spawning substrate for species with adhesive eggs such as Banded Killifish (Fundulus diaphanus), which is now the most abundant species in the embayment. Other changes observed were a decrease in the relative contribution of open water dwelling species such as White Perch (Morone americana), and an increase of visual predators such as Largemouth Bass (Micropterus salmoides). The 30-year record of data from this Potomac River tributary has revealed important long-term trends that validate the effectiveness of initiatives to reduce excess nutrient inputs, and will aid in the continued management of the watershed and point-source inputs. Full article
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Open AccessFeature PaperArticle Bridging Glaciological and Hydrological Trends in the Pamir Mountains, Central Asia
Water 2017, 9(6), 422; doi:10.3390/w9060422
Received: 22 March 2017 / Revised: 27 May 2017 / Accepted: 4 June 2017 / Published: 13 June 2017
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Abstract
With respect to meteorological changes and glacier evolution, the southern Pamir Mountains are a transition zone between the Pamirs, Hindu Kush and Karakoram, which are water towers of Central Asia. In this study, we compare runoff and climate trends in multiple time periods
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With respect to meteorological changes and glacier evolution, the southern Pamir Mountains are a transition zone between the Pamirs, Hindu Kush and Karakoram, which are water towers of Central Asia. In this study, we compare runoff and climate trends in multiple time periods with glacial changes reported in the literature. Recent glacier evolution in the Southern Pamirs and its contribution to river runoff are studied in detail. Uncertainties of estimating glacier retreat contribution to runoff are addressed. Runoff trends in the Pamir-Hindu Kush-Karakoram region appear to be a strong proxy for glacier evolution because they exhibit the same spatial pattern as glacial change. There is an anomaly in the North-West Pamirs and Northern Karakoram, showing decreasing runoff trends. In the opposite way, there is a glacier and hydrological change experienced in the Southern Pamirs and Hindu Kush. The prevailing hypothesis for the Karakoram Anomaly, decreasing summer temperatures along with increasing precipitation rates, seems to be valid for the North-Western Pamirs, as well. In the Southern Pamirs, temperature trends have been rising since 1950. Here, the unique water cycle of exclusively winter precipitation does not protect glaciers from accelerated retreat. Snow cover is preset to melt within the seasonal water cycle, due to much lower precipitation amounts falling on glaciers. Therefore, a probable increase in westerly precipitation in both regions causes glacier mass gain in the Northern Pamirs and rising river flows in the Southern Pamirs. Full article
(This article belongs to the Special Issue Global Warming Impacts on Mountain Glaciers and Communities)
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Open AccessArticle Effects of Coordinated Operation of Weirs and Reservoirs on the Water Quality of the Geum River
Water 2017, 9(6), 423; doi:10.3390/w9060423
Received: 14 March 2017 / Revised: 22 May 2017 / Accepted: 31 May 2017 / Published: 12 June 2017
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Abstract
Multifunctional weirs can be used to maintain water supply during dry seasons and to improve downstream water quality during drought conditions through discharge based on retained flux. Sixteen multifunctional weirs were recently constructed in four river systems as part of the Four Rivers
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Multifunctional weirs can be used to maintain water supply during dry seasons and to improve downstream water quality during drought conditions through discharge based on retained flux. Sixteen multifunctional weirs were recently constructed in four river systems as part of the Four Rivers Restoration Project. In this study, three multifunctional weirs in the Geum River Basin were investigated to analyze the environmental effects of multifunctional weir operation on downstream flow. To determine seasonal vulnerability to drought, the basin was evaluated using the Palmer Drought Severity Index (PDSI). Furthermore, the downstream flow regime and the effect on water quality improvement of a coordinated dam–multifunctional weir operation controlled by: (a) a rainfall–runoff model; (b) a reservoir optimization model; and (c) a water quality model, were examined. A runoff estimate at each major location in the Geum River Basin was performed using the water quality model, and examined variation in downstream water quality depending on the operational scenario of each irrigation facility such as dams and weirs. Although the water quality was improved by the coordinated operation of the dams and weirs, when the discharged water quality is poor, the downstream water quality is not improved. Therefore, it is necessary to first improve the discharged water quality on the lower Geum River. Improvement of the water quality of main stream in the Geum River is important, but water quality from tributaries should also be improved. By applying the estimated runoff data to the reservoir optimization model, these scenarios will be utilized as basic parameters for assessing the optimal operation of the river. Full article
(This article belongs to the Special Issue Water Networks Management: New Perspectives)
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Open AccessArticle Risk Analysis of Reservoir Operations Considering Short-Term Flood Control and Long-Term Water Supply: A Case Study for the Da-Han Creek Basin in Taiwan
Water 2017, 9(6), 424; doi:10.3390/w9060424
Received: 3 February 2017 / Revised: 7 June 2017 / Accepted: 8 June 2017 / Published: 12 June 2017
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Abstract
This study applies an integrated methodology to assess short-term over-levee risk and long-term water shortage risk in the Da-Han Creek basin, which is the most important flood control and water storage system in northern Taiwan. An optimization model for reservoir flood control and
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This study applies an integrated methodology to assess short-term over-levee risk and long-term water shortage risk in the Da-Han Creek basin, which is the most important flood control and water storage system in northern Taiwan. An optimization model for reservoir flood control and water supply is adopted, to determine reservoir releases based on synthetic inflow hydrographs during typhoons, which are generated by Monte Carlo simulations. The release is then used to calculate the water level at a downstream control point using a novel developed back-propagation neural network-based model, to reduce computational complexity and achieve automatic-efficient risk evaluation. The calculated downstream water levels and final reservoir water levels after a typhoon event are used to evaluate the mapped over-levee risk and water shortage risk, respectively. The results showed that the different upper limit settings for the reservoir have a significant influence on the variation of 1.19 × 10−5% to 75.6% of the water shortage risk. This occurs because of the insufficient inflow and narrow storage capacity of the Shih-Men Reservoir during drought periods. However, the upper limit settings have a minor influence (with a variation of only 0.149% to 0.157%) on the over-levee risk in typhoon periods, because of the high protection standards for the downstream embankment. Full article
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Open AccessArticle Analysis of Water Tariff Reform on Water Consumption in Different Housing Typologies in Calvià (Mallorca)
Water 2017, 9(6), 425; doi:10.3390/w9060425
Received: 10 April 2017 / Revised: 1 June 2017 / Accepted: 8 June 2017 / Published: 12 June 2017
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Abstract
This study analyses water prices and residential water consumption using micro data for three different housing typologies in Calvia with contrasting household characteristics. We examine the effect of a price reform of the sanitation fee (implemented in 2013) on the average prices and
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This study analyses water prices and residential water consumption using micro data for three different housing typologies in Calvia with contrasting household characteristics. We examine the effect of a price reform of the sanitation fee (implemented in 2013) on the average prices and their water consumption in each of the areas. Our results conclude that the aggregate water consumption decreased only during the year of the reform, but increased the following year. The increase in the amount of water consumed by the houses of higher standards of living was greater than the small decrease in water consumption by families with medium and low-medium incomes. Thus, the reform had a very modest effect as regards reducing water consumption, and many households increased their consumption despite the higher prices. From a water policy perspective, we recommend a water tariff scheme differentiated according to the housing characteristics in order to find the most effective and fairest way to save water. Full article
(This article belongs to the collection Water Policy Collection)
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Open AccessArticle Dual-Control of Autothermal Thermophilic Aerobic Digestion Using Aeration and Solid Retention Time
Water 2017, 9(6), 426; doi:10.3390/w9060426
Received: 11 March 2017 / Revised: 16 May 2017 / Accepted: 9 June 2017 / Published: 13 June 2017
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Abstract
Autothermal thermophilic aerobic digestion (ATAD) is an advanced sewage sludge treatment which allows compliance with increasingly demanding regulations. Concerning sludge pasteurization, a certain average temperature must be assured in the digester during batch treatment. Aeration flow is the variable most manipulated to regulate
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Autothermal thermophilic aerobic digestion (ATAD) is an advanced sewage sludge treatment which allows compliance with increasingly demanding regulations. Concerning sludge pasteurization, a certain average temperature must be assured in the digester during batch treatment. Aeration flow is the variable most manipulated to regulate the digester temperature. Additionally, the manipulation of the batch sludge flow—which is related to the solid-retention-time—is considered to improve temperature regulation despite variations in air and sludge temperatures and the variability of raw sludge organic content. Thus, a dual-input control structure was provided where the aeration and solid-retention-time contributed as faster and slower inputs, respectively. Two controllers intervened, and the set-point for the batch average temperature was chosen to meet the minimum effluent quality established by the US regulations or European recommendations, considering that lower set point temperatures save aeration costs. A set-point for the aeration allowed us to achieve an extra goal, which aimed at either reducing operation costs or increasing production rates. The two feedback controllers were designed following the robust control methodology known as quantitative feedback theory (QFT). Improvements were compared with single-input (aeration-flow) control strategy and open-loop control strategy. Simulations were performed on a benchmark non-linear simulation model for ATAD. Full article
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Open AccessArticle Peracetic Acid (PAA) Disinfection: Inactivation of Microbial Indicators and Pathogenic Bacteria in a Municipal Wastewater Plant
Water 2017, 9(6), 427; doi:10.3390/w9060427
Received: 4 May 2017 / Revised: 7 June 2017 / Accepted: 8 June 2017 / Published: 13 June 2017
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Abstract
Several studies have noted that treated and untreated wastewaters are primary contributors of a variety of pathogenic microorganisms to the aquatic ecosystem. Conventional wastewater treatment may not be sufficient to achieve microbiologically safe effluent to be discharged into natural waters or reused, thus
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Several studies have noted that treated and untreated wastewaters are primary contributors of a variety of pathogenic microorganisms to the aquatic ecosystem. Conventional wastewater treatment may not be sufficient to achieve microbiologically safe effluent to be discharged into natural waters or reused, thus requiring wastewater effluents to be disinfected. In recent years, peracetic acid (PAA) has been adopted as a disinfectant for wastewater effluents. The aim of this study was to evaluate the disinfection efficiency of PAA at low doses (range 0.99–2.10 mg/L) against microbial indicators and pathogenic bacteria in a municipal wastewater plant. Samples of untreated sewage and effluents before and after PAA treatment were collected seasonally for 1 year and were analysed for pathogenic Campylobacter, Salmonella spp., E. coli O157:H7 and E. coli virulence genes using molecular methods; moreover, the detection of specific microbial indicators (E. coli, faecal coliforms, enterococci, C. perfringens) and Salmonella spp. were carried out using culturing methods. Salmonella spp. DNA was found in all untreated sewage and effluent before PAA treatment, whereas it was recovered in 50% of the samples collected after PAA treatment. Although E. coli O157:H7 was never identified, the occurrence of Shiga-like toxin I amplicons was identified in 75% of the untreated sewage samples, in 50% of the effluents assayed before PAA treatment, and in 25% of the effluents assayed after PAA treatment, whereas the stx2 gene was never found. Campylobacter coli was only detected in one effluent sample before PAA treatment. In the effluents after PAA treatment, a lower load of indicator bacteria was observed compared to the effluents before treatment. The results of this study highlight that the use of low doses of PAA seems to lead to an improvement of the microbiological quality of the effluent, although it is not sufficient to guarantee its suitability for irrigation. These results underscore the need for additional studies to further assess the efficiency of PAA disinfection in municipal wastewater plants. Full article
(This article belongs to the Special Issue New Advances in Disinfection of Wastewater)
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Open AccessArticle Development of Resilience Index Based on Flooding Damage in Urban Areas
Water 2017, 9(6), 428; doi:10.3390/w9060428
Received: 10 April 2017 / Revised: 19 May 2017 / Accepted: 9 June 2017 / Published: 13 June 2017
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Abstract
Flooding volume in urban areas is not linearly proportional to flooding damage because, in some areas, no flooding damage occurs until the flooding depth reaches a certain point, whereas flooding damage occurs in other areas whenever flooding occurs. Flooding damage is different from
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Flooding volume in urban areas is not linearly proportional to flooding damage because, in some areas, no flooding damage occurs until the flooding depth reaches a certain point, whereas flooding damage occurs in other areas whenever flooding occurs. Flooding damage is different from flooding volume because each subarea has different components. A resilience index for urban drainage systems was developed based on flooding damage. In this study, the resilience index based on flooding damage in urban areas was applied to the Sintaein basin in Jeongup, Korea. The target watershed was divided into five subareas according to the status of land use in each subarea. The damage functions between flooding volume and flooding damage were calculated by multi-dimensional flood damage analysis. The extent of flooding damage per minute was determined from the results of flooding volume per minute using damage functions. The values of the resilience index based on flooding damages were distributed from 0.797292 to 0.933741. The resilience index based on flooding damage suggested in this study can reflect changes in urban areas and can be used for the evaluation of flood control plans such as the installation, replacement, and rehabilitation of drainage facilities. Full article
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Open AccessArticle Effects of Selected Root Exudate Components on Nitrogen Removal and Development of Denitrifying Bacteria in Constructed Wetlands
Water 2017, 9(6), 430; doi:10.3390/w9060430
Received: 26 March 2017 / Revised: 2 June 2017 / Accepted: 10 June 2017 / Published: 13 June 2017
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Abstract
Root exudates, particularly low molecular weight carbon (LMWC) substrates, are major drivers of bacterial diversity and activity in the rhizosphere environment. However, it is not well understood how specific LMWC compounds—such as organic acids, soluble sugars, and amino acids—influence the community structures of
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Root exudates, particularly low molecular weight carbon (LMWC) substrates, are major drivers of bacterial diversity and activity in the rhizosphere environment. However, it is not well understood how specific LMWC compounds—such as organic acids, soluble sugars, and amino acids—influence the community structures of denitrifying bacteria or if there are specific functions of LMWC substrates that preferentially respond to nitrogen (N) removal in constructed wetlands (CWs). To address these knowledge gaps, we added mixtures of artificial exudates to CW microcosms containing N pollutant. N removal efficiency was observed over a 48-h experimental period, and at the end of the experiment, DNA was extracted from microbial samples for assessment of the bacterial community. The removal efficiencies of TN for the exudates treatments were higher than for control groups by 47.1–58.67%. Organic acid and soluble sugar treatments increased N removal, while amino acids were negative to N removal. The microbial community was changed when artificial exudates were added, but there were no significant relationships between LMWC compounds and bacterial community composition. These results indicate that although the responses of community structures of denitrifying bacteria to LMWC additions are still uncertain, there is evidence for N removal in response to exudate additions across LMWC types. Full article
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Open AccessArticle Nutrients and Phytoplankton in a Shallow, Hypereutrophic Urban Lake: Prospects for Restoration
Water 2017, 9(6), 431; doi:10.3390/w9060431
Received: 11 May 2017 / Revised: 8 June 2017 / Accepted: 12 June 2017 / Published: 14 June 2017
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Abstract
University Lake, a shallow, artificial, urban lake adjacent to the campus of Louisiana State University, has a long history of water quality problems, including algal blooms, fish kills, and high concentrations of fecal indicator bacteria. Periodic dredging of the lake is necessary to
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University Lake, a shallow, artificial, urban lake adjacent to the campus of Louisiana State University, has a long history of water quality problems, including algal blooms, fish kills, and high concentrations of fecal indicator bacteria. Periodic dredging of the lake is necessary to prevent its return to swampland. This study was undertaken to elucidate the roles of allochthonous versus autochthonous nutrients as causes of water quality problems in the lake, with the expectation that this information would help identify strategies for lake restoration. Photosynthetic rates and concentrations of inorganic nutrients and phytoplankton pigments were measured over a period of one year. More than 90% of the chlorophyll a (chl a) in the lake was accounted for by Chlorophyceae, Cyanophyceae, and Bacillariophyceae. Concentrations of chl a, which averaged 75 μg L−1, fluctuated weekly during dry weather by as much as a factor of four. Phytoplankton growth rates were about 30% higher 1–2 days after rain events than after periods of dry weather, the implication being that allochthonous nutrient loading has a significant effect on the dynamics of the phytoplankton community in the lake. Therefore, dredging of sediments will likely produce no long-term improvement in water quality. More than 100 storm drains currently discharge into the lake, and diversion of those drains may be the most cost-effective strategy for effecting a long-term improvement in water quality. Full article
(This article belongs to the Special Issue Water Quality Monitoring and Modeling in Lakes)
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Open AccessArticle Two-Dimensional Dam-Break Flood Analysis in Data-Scarce Regions: The Case Study of Chipembe Dam, Mozambique
Water 2017, 9(6), 432; doi:10.3390/w9060432
Received: 15 February 2017 / Revised: 6 June 2017 / Accepted: 8 June 2017 / Published: 14 June 2017
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Abstract
This paper presents the results of a modeling study of the hypothetical dam break of Chipembe dam in Mozambique. The modeling approach is based on the software Iber, a freely available dam break and two-dimensional finite volume shallow water model. The shuttle radar
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This paper presents the results of a modeling study of the hypothetical dam break of Chipembe dam in Mozambique. The modeling approach is based on the software Iber, a freely available dam break and two-dimensional finite volume shallow water model. The shuttle radar topography mission (SRTM) online digital elevation model (DEM) is used as main source of topographic data. Two different DEMs are considered as input for the hydraulic model: a DEM based on the original SRTM data and a hydrologically-conditioned DEM. A sensitivity analysis on the Manning roughness coefficient is performed. The results demonstrate the relevant impact of the DEM used on the predicted flood wave propagation, and a lower influence of the roughness value. The low cost modeling approach proposed in this paper can be an attractive option for modeling exceptional flood caused by dam break, when limited data and resources are available, as in the presented case. The resulting flood-inundation and hazard maps will enable the Regional Water Management Administration of Mozambique (ARA) to develop early warning systems. Full article
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Open AccessArticle Influence of Anionic Surfactant on Saturated Hydraulic Conductivity of Loamy Sand and Sandy Loam Soils
Water 2017, 9(6), 433; doi:10.3390/w9060433
Received: 20 December 2016 / Revised: 24 April 2017 / Accepted: 22 May 2017 / Published: 15 June 2017
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Abstract
Surfactants released into the terrestrial environment in large amounts can potentially alter the physical, chemical and biological properties of soils, particularly the saturated hydraulic conductivity (Ks). Unfortunately findings regarding this process are quite limited. In this study, column tests were
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Surfactants released into the terrestrial environment in large amounts can potentially alter the physical, chemical and biological properties of soils, particularly the saturated hydraulic conductivity (Ks). Unfortunately findings regarding this process are quite limited. In this study, column tests were used to analyze the effects of Aerosol 22, a widely used anionic surfactant, on Ks of loamy sand and sandy loam soils. Solutions were injected into columns from the bottom with controlled pressure heads. Both the overall Ks of columns and the Ks of 6 layers at distances of 0–1 cm, 1–3 cm, 3–5 cm, 5–7 cm, 7–9 cm, and 9–10 cm from the bottom, were continuously monitored before and after the surfactant injections. Results showed that the overall Ks of all columns decreased after 2–4 pore volumes of the surfactant injections. However, stabilization and even increase at the beginning of the surfactant injection was also observed due to the different Ks variations in different layers. Specifically, a surfactant injection of 2–4 pore volumes continuously decreased the Ks of the 0–1 cm layers which yielded a Ks reduction of two orders of magnitude and dominated the Ks variations of the column. In contrast, an increase in the Ks of the 1–3 cm and 3–5 cm layers was more likely, while Ks variation of the 5–10 cm layers was less likely. We hypothetically attributed the Ks variations to the swelling of clay, the collapse of soil aggregates and subsequent particle displacements from surfactant adsorption, which caused pore clogging in the bottom 0–1 cm layer and higher porosities in the layers above. The adsorption of the surfactant aggregates and crystallization were also possibly thought to cause a pore clogging in the bottom layer thus decrease the surfactant concentration from the inlet, the severity of which affects these layers less at greater distances from the inlet. In view of the uncertainty showed by the experimental results, we also suggest to include more replicate columns in future studies, so as to increase the repeatability of the measurements. Full article
(This article belongs to the Special Issue Water and Solute Transport in Vadose Zone)
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Open AccessArticle Singapore and Sydney: Regulation and Market-Making
Water 2017, 9(6), 434; doi:10.3390/w9060434
Received: 9 March 2017 / Revised: 1 June 2017 / Accepted: 12 June 2017 / Published: 15 June 2017
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Abstract
The different institutional forms of water utilities of Singapore and Sydney provide an interesting natural experiment on the role of a regulator in government-owned utilities (GOUs). In both cities, water is provided by GOUs. In Sydney, however, there is an independent regulator whereas
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The different institutional forms of water utilities of Singapore and Sydney provide an interesting natural experiment on the role of a regulator in government-owned utilities (GOUs). In both cities, water is provided by GOUs. In Sydney, however, there is an independent regulator whereas in Singapore the Public Utilities Board is a statutory board without a regulator. This paper compared the regulation and market-making efforts by water utilities of Singapore and Sydney. We find that both are similar in quality of service, operational and economic efficiencies, and private sector investments. The difference lies in their choice of the instrument for involving the private sector. Sydney does this by appointing a specific regulator whereas Singapore uses contracts. Indeed, it argues that the government-owned water utilities of both Sydney and Singapore seek to capture as many benefits as possible from market-making efforts, that is, from mimicking private sector behaviors and by operating from the basic tenets of the regulatory state. Both countries seek to make rules addressing the “market failure” of a monopoly. In Sydney, such efforts are seen in the explicit contestability of the market and the high engagement with customers whereas in Singapore the efforts are more muted on both counts and are instead motivated toward developing water businesses as a whole Full article
Open AccessArticle Development of a Station Based Climate Database for SWAT and APEX Assessments in the US
Water 2017, 9(6), 437; doi:10.3390/w9060437
Received: 11 May 2017 / Revised: 7 June 2017 / Accepted: 14 June 2017 / Published: 17 June 2017
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Abstract
Water quality simulation models such as the Soil and Water Assessment Tool (SWAT) and Agricultural Policy EXtender (APEX) are widely used in the US. These models require large amounts of spatial and tabular data to simulate the natural world. Accurate and seamless daily
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Water quality simulation models such as the Soil and Water Assessment Tool (SWAT) and Agricultural Policy EXtender (APEX) are widely used in the US. These models require large amounts of spatial and tabular data to simulate the natural world. Accurate and seamless daily climatic data are critical for accurate depiction of the hydrologic cycle, yet these data are among the most difficult to obtain and process. In this paper we describe the development of a national (US) database of preprocessed climate data derived from monitoring stations applicable to USGS 12-digit watersheds. Various sources and processing methods are explored and discussed. A relatively simple method was employed to choose representative stations for each of the 83,000 12-digit watersheds in the continental US. Fully processed climate data resulting from this research were published online to facilitate other SWAT and APEX modeling efforts in the US. Full article
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Open AccessArticle Runoff Effect Evaluation of LID through SWMM in Typical Mountainous, Low-Lying Urban Areas: A Case Study in China
Water 2017, 9(6), 439; doi:10.3390/w9060439
Received: 30 June 2016 / Revised: 5 June 2017 / Accepted: 8 June 2017 / Published: 19 June 2017
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Abstract
Urban flooding occurs frequently in many regions of China. To reduce the losses caused by urban flooding, sponge city (SPC) and low-impact development (LID) have been carried out in many Chinese cities. However, urban flooding is influenced by various factors, such as climate,
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Urban flooding occurs frequently in many regions of China. To reduce the losses caused by urban flooding, sponge city (SPC) and low-impact development (LID) have been carried out in many Chinese cities. However, urban flooding is influenced by various factors, such as climate, land cover characteristics and nearby river networks, so it is necessary to evaluate the effectiveness of LID measures. In this study, the Storm Water Management Model (SWMM) was adopted to simulate historical urban storm processes in the mountainous Fragrance Hills region of Beijing, China. Subsequently, numerical simulations were performed to evaluate how various LID measures (concave greenbelt, permeable pavement, bio-retention, vegetative swales, and comprehensive measures) influenced urban runoff reduction. The results showed that the LID measures are effective in controlling the surface runoff of the storm events with return periods shorter than five years, in particular, for one-year events. Furthermore, the effectiveness on traffic congestion mitigation of several LID measures (concave greenbelt, vegetative swales, and comprehensive measures) was evaluated. However, the effective return periods of storm events are shorter than two years if the effectiveness on traffic congestion relief is considered. In all evaluated aspects, comprehensive measures and concave greenbelts are the most effective, and vegetative swale is the least effective. This indicated that LID measures are less effective for removing ponding from most storm events in a mountainous, low-lying and backward pipeline infrastructure region with pressures from interval flooding and urban waterlogging. The engineering measures including water conservancy projects and pipeline infrastructure construction combined with the non-engineering measures were suggested to effectively control severe urban storms. Full article
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Open AccessArticle Methodology for Analyzing and Predicting the Runoff and Sediment into a Reservoir
Water 2017, 9(6), 440; doi:10.3390/w9060440
Received: 11 May 2017 / Revised: 16 June 2017 / Accepted: 16 June 2017 / Published: 19 June 2017
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Abstract
With the rapid economic growth in China, a large number of hydropower projects have been planned and constructed. The sediment deposition of the reservoirs is one of the most important disputes during the construction and operation, because there are many heavy sediment-laden rivers.
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With the rapid economic growth in China, a large number of hydropower projects have been planned and constructed. The sediment deposition of the reservoirs is one of the most important disputes during the construction and operation, because there are many heavy sediment-laden rivers. The analysis and prediction of the runoff and sediment into a reservoir is of great significance for reservoir operation. With knowledge of the incoming runoff and sediment characteristics, the regulator can adjust the reservoir discharge to guarantee the water supply, and flush more sediment at appropriate times. In this study, the long-term characteristics of runoff and sediment, including trend, jump point, and change cycle, are analyzed using various statistical approaches, such as accumulated anomaly analysis, the Fisher ordered clustering method, and Maximum Entropy Spectral Analysis (MESA). Based on the characteristics, a prediction model is established using the Auto-Regressive Moving Average (ARIMA) method. The whole analysis and prediction system is applied to The Three Gorges Project (TGP), one of the biggest hydropower-complex projects in the world. Taking hydrologic series from 1955 to 2010 as the research objectives, the results show that both the runoff and the sediment are decreasing, and the reduction rate of sediment is much higher. Runoff and sediment into the TGP display cyclic variations over time, with a cycle of about a decade, but catastrophe points for runoff and sediment appear in 1991 and 2001, respectively. Prediction models are thus built based on monthly average hydrologic series from 2003 to 2010. ARIMA (1, 1, 1) × (1, 1, 1)12 and ARIMA (0, 1, 1) × (0, 1, 1)12 are selected for the runoff and sediment predictions, respectively, and the parameters of the models are also calibrated. The analysis of autocorrelation coefficients and partial autocorrelation coefficients of the residuals indicates that the models built in this study are feasible for representing and predicting the runoff and sediment inflow into the TGP with a high accuracy. Full article
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Open AccessArticle The Design of a Site-Calibrated Parker–Klingeman Gravel Transport Model
Water 2017, 9(6), 441; doi:10.3390/w9060441
Received: 2 May 2017 / Revised: 12 June 2017 / Accepted: 15 June 2017 / Published: 20 June 2017
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Abstract
The use of site-calibrated models for predicting bedload transport in gravel-bed rivers remains relatively rare, despite advances in methodology and computing technology, and its notable advantages in terms of predictive accuracy. This article presents a new algorithm for site calibration of the Parker–Klingeman
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The use of site-calibrated models for predicting bedload transport in gravel-bed rivers remains relatively rare, despite advances in methodology and computing technology, and its notable advantages in terms of predictive accuracy. This article presents a new algorithm for site calibration of the Parker–Klingeman (1982) model, along with a detailed discussion of considerations that influence model selection and calibration methodology. New visualization techniques are explored to demystify the calibration process, using three examples with progressively more challenging calibration conditions. The new method is particularly well suited to streams with high sediment loads, or cases where extrapolation of transport function estimates is necessary. Full article
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Open AccessFeature PaperArticle Transparency, Geomorphology and Mixing Regime Explain Variability in Trends in Lake Temperature and Stratification across Northeastern North America (1975–2014)
Water 2017, 9(6), 442; doi:10.3390/w9060442
Received: 28 April 2017 / Revised: 9 June 2017 / Accepted: 14 June 2017 / Published: 20 June 2017
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Abstract
Lake surface water temperatures are warming worldwide, raising concerns about the future integrity of valuable lake ecosystem services. In contrast to surface water temperatures, we know far less about what is happening to water temperature beneath the surface, where most organisms live. Moreover,
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Lake surface water temperatures are warming worldwide, raising concerns about the future integrity of valuable lake ecosystem services. In contrast to surface water temperatures, we know far less about what is happening to water temperature beneath the surface, where most organisms live. Moreover, we know little about which characteristics make lakes more or less sensitive to climate change and other environmental stressors. We examined changes in lake thermal structure for 231 lakes across northeastern North America (NENA), a region with an exceptionally high density of lakes. We determined how lake thermal structure has changed in recent decades (1975–2012) and assessed which lake characteristics are related to changes in lake thermal structure. In general, NENA lakes had increasing near-surface temperatures and thermal stratification strength. On average, changes in deepwater temperatures for the 231 lakes were not significantly different than zero, but individually, half of the lakes experienced warming and half cooling deepwater temperature through time. More transparent lakes (Secchi transparency >5 m) tended to have higher near-surface warming and greater increases in strength of thermal stratification than less transparent lakes. Whole-lake warming was greatest in polymictic lakes, where frequent summer mixing distributed heat throughout the water column. Lakes often function as important sentinels of climate change, but lake characteristics within and across regions modify the magnitude of the signal with important implications for lake biology, ecology and chemistry. Full article
(This article belongs to the Special Issue Ecological Responses of Lakes to Climate Change)
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Open AccessArticle Evaluation of Groundwater Remediation Technologies Based on Fuzzy Multi-Criteria Decision Analysis Approaches
Water 2017, 9(6), 443; doi:10.3390/w9060443
Received: 30 March 2017 / Revised: 13 June 2017 / Accepted: 15 June 2017 / Published: 20 June 2017
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Abstract
Petroleum is an essential resource for the development of society and its production is huge. There is a great risk of leakage of oil during production, refining, and transportation. After entering the environment, the oil pollutants will be a great threat to the
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Petroleum is an essential resource for the development of society and its production is huge. There is a great risk of leakage of oil during production, refining, and transportation. After entering the environment, the oil pollutants will be a great threat to the environment and may endanger human health. Therefore, it is very important to remediate oil pollution in the subsurface. However, it is necessary to choose the appropriate remediation technology. In this paper, 18 technologies are evaluated through constructing a parameter matrix with each technology and seven performance indicators, and a comprehensive analysis model is presented. In this model, four MCDA methods are used. They are SWA (Simple Weighted Addition Method), WP (Weighted Product Method), CGT (Cooperative Game Theory), and TOPSIS (Technique for Order Preference by Similarity to Ideal Solution). Mean ranking and Borda ranking methods are used to integrate the results of SWA, WP, CGT, and TOPSIS. Then two selection priorities of each method (mean ranking and Borda ranking) are obtained. The model is proposed to help decide the best choice of remediation technologies. It can effectively reduce contingency, subjectivity, one-sidedness of the traditional methods and provide scientific reference for effective decision-making. Full article
(This article belongs to the Special Issue Modeling of Water Systems)
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Open AccessArticle Spatial Variation, Pollution Assessment and Source Identification of Major Nutrients in Surface Sediments of Nansi Lake, China
Water 2017, 9(6), 444; doi:10.3390/w9060444
Received: 12 May 2017 / Revised: 10 June 2017 / Accepted: 12 June 2017 / Published: 20 June 2017
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Abstract
Nansi Lake has been seriously affected by intensive anthropogenic activities in recent years. In this study, an extensive survey on spatial variation, pollution assessment as well as the possible sources identification of major nutrients (Total phosphorus: TP, Total nitrogen: TN, and Total organic
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Nansi Lake has been seriously affected by intensive anthropogenic activities in recent years. In this study, an extensive survey on spatial variation, pollution assessment as well as the possible sources identification of major nutrients (Total phosphorus: TP, Total nitrogen: TN, and Total organic carbon: TOC) in the surface sediments of Nansi Lake was conducted. Results showed that the mean contents of TP, TN and TOC were 1.13-, 5.40- and 2.50- fold higher than their background values respectively. Most of the TN and TOC contents in the surface sediments of Nansi Lake were four times as high or higher and twice as high or higher than the background values except the Zhaoyang sub-lake, and the spatial distribution of TN and TOC contents were remarkably similar over a large area. Nearly all the TP contents in the surface sediments of Nansi Lake were all higher than its background values except most part of the Zhaoyang sub-lake. Based on the enrichment factor (EF) and the organic pollution evaluation index (Org-index), TP, TOC and TN showed minor enrichment (1.13), minor enrichment (2.50) and moderately severe enrichment (5.40), respectively, and most part of the Dushan sub-lake and the vicinity of the Weishan island were in moderate or heavy sediments organic pollution, while the other parts were clean. Moreover, according to the results of multivariate statistical analysis, we deduced that anthropogenic TN and TOC were mainly came from industrial sources including enterprises distributed in Jining, Yanzhou and Zoucheng along with iron and steel industries distributed in the southern of the Weishan sub-lake, whereas TP mainly originated from runoff and soil erosion coming from agricultural lands located in Heze city and Weishan island, the local aquacultural activities as well as the domestic sewage discharge of Jining city. Full article
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Open AccessArticle Urban Flood Simulation Using MODCEL—An Alternative Quasi-2D Conceptual Model
Water 2017, 9(6), 445; doi:10.3390/w9060445
Received: 24 March 2017 / Revised: 11 June 2017 / Accepted: 13 June 2017 / Published: 21 June 2017
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Abstract
Urban flood modelling has been evolving in recent years, due to computational facilities as well as to the possibility of obtaining detailed terrain data. Flood control techniques have also been evolving to integrate both urban flood and urban planning issues. Land use control
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Urban flood modelling has been evolving in recent years, due to computational facilities as well as to the possibility of obtaining detailed terrain data. Flood control techniques have also been evolving to integrate both urban flood and urban planning issues. Land use control and flow generation concerns, as well as a set of possible distributed measures favouring storage and infiltration over the watershed, also gained importance in flood control projects, reinforcing the need to model the entire basin space. However, the use of 2D equations with highly detailed digital elevation models do not guarantee good results by their own. Urban geometry, including buildings shapes, walls, earth fills, and other structures may cause significant interference on flood paths. In this context, this paper presents an alternative urban flood model, focusing on the system behaviour and its conceptual interpretation. Urban Flood Cell Model-MODCEL is a hydrological-hydrodynamic model proposed to represent a complex flow network, with a set of relatively simple information, using average values to represent urban landscape through the flow-cell concept. In this work, to illustrate model capabilities, MODCEL is benchmarked in a test proposed by the British Environmental Agency. Then, its capability to represent storm drains is verified using measured data and a comparison with Storm Water Management Model (SWMM). Finally, it is applied in a lowland area of the Venetian continental plains, representing floods in a complex setup at the city of Noale and in its surroundings. Full article
(This article belongs to the Special Issue Modeling of Water Systems)
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Open AccessCommunication Effects of Thinning on Flow Peaks in a Forested Headwater Catchment in Western Japan
Water 2017, 9(6), 446; doi:10.3390/w9060446
Received: 25 April 2017 / Revised: 16 June 2017 / Accepted: 18 June 2017 / Published: 21 June 2017
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Abstract
This study examined the changes in rainfall-runoff characteristics in the year prior to and after intensive thinning of 50% in number in a steep headwater catchment, covered with 46-year-old Japanese cedar and cypress in western Japan. The magnitude of event peak flow, event
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This study examined the changes in rainfall-runoff characteristics in the year prior to and after intensive thinning of 50% in number in a steep headwater catchment, covered with 46-year-old Japanese cedar and cypress in western Japan. The magnitude of event peak flow, event quick flow, event water yield, and event response time did not change after thinning. Because 70% of rainfall events had multiple flow peaks, relationships between each flow peak and the rainfall just prior to that peak were also analyzed. The increases in accumulated quick flow, flow rise and flow drop were significant after thinning. The flow drop following each flow peak increased, and led to a lower initial flow in subsequent peaks, resulting in no increase in peak size. The flow peaks in events with over 30 mm rainfall amount and over 2 mm/h average rainfall intensity showed significant increases in flow peak, flow rise, flow drop, and accumulated quick flow, which suggests that the catchment exhibited more shallow flow paths during large rainfall amounts after thinning. No changes were identified using event-based analysis, but changes in flow peaks were detected, which indicates the importance of examining all flow peaks when investigating rainfall-runoff characteristics of headwater catchments. Full article
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Open AccessArticle Beach Response to Wave Forcing from Event to Inter-Annual Time Scales at Grand Popo, Benin (Gulf of Guinea)
Water 2017, 9(6), 447; doi:10.3390/w9060447
Received: 31 March 2017 / Revised: 14 June 2017 / Accepted: 16 June 2017 / Published: 21 June 2017
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Abstract
This paper assesses the morphological storm-event impact, seasonal cycles, trends of wave forcing, and beach’s response at the coastal area of Grand Popo, Benin. Three and a half years’ worth of data were collected from 2013 to 2016, using a video system calibrated
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This paper assesses the morphological storm-event impact, seasonal cycles, trends of wave forcing, and beach’s response at the coastal area of Grand Popo, Benin. Three and a half years’ worth of data were collected from 2013 to 2016, using a video system calibrated with field data collected during a 10 day experiment. A comparison was carried out with Wavewatch III IOWAGA wave hindcast data. The along-shore-averaged shoreline position exhibited a seasonal pattern, which was related more to the average wave height than the average storm intensity. Storms occur in austral winter (June, July, August, and September). Based on 12 storms, the results revealed that the average storm duration was 1.6 days, with a mean erosion of 3.1 m. The average post-storm beach recovery duration was 15 days, and the average recovery rate was 0.4 m/day. The impact of storms was more or less amplified depending on the eroding and accreting periods of the wave climate. There was an inter-annual eroding trend of about −1.6 m/year, but the causes of this trend could not be explained. Full article
(This article belongs to the Special Issue Sediment Transport in Coastal Waters)
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Open AccessArticle Model of Suspended Solids Removal in the Primary Sedimentation Tanks for the Treatment of Urban Wastewater
Water 2017, 9(6), 448; doi:10.3390/w9060448
Received: 24 May 2017 / Revised: 13 June 2017 / Accepted: 14 June 2017 / Published: 21 June 2017
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Abstract
Primary settling tanks are used to remove solids at wastewater treatment plants and are considered a fundamental part in their joint operation with the biological and sludge treatment processes. The aim of this study was to obtain a greater understanding of the influence
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Primary settling tanks are used to remove solids at wastewater treatment plants and are considered a fundamental part in their joint operation with the biological and sludge treatment processes. The aim of this study was to obtain a greater understanding of the influence of operational parameters, such as surface overflow rate, hydraulic retention time, and temperature, on the removal efficiency of suspended solids and organic matter by the measurement of chemical oxygen demand and biochemical oxygen demand in the primary sedimentation process. The research was carried out in a semi-technical primary settling tank which was fed with real wastewater from a wastewater treatment plant. The physical process was strictly controlled and without the intervention of chemical additives. Three cycles of operation were tested in relation to the surface overflow rate, in order to check their influence on the different final concentrations. The results obtained show that the elimination efficiency can be increased by 11% for SS and 9% for chemical oxygen demand and biochemical oxygen demand, for variations in the surface overflow rate of around ±0.6 m3/m2·h and variations in hydraulic retention time of around ±2 h. The results also show that current design criteria are quite conservative. An empirical mathematical model was developed in this paper relating SS removal efficiency to q, influent SS concentration, and sewage temperature. Full article
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Open AccessArticle Dissipation of Micropollutants in a Rewetted Fen Peatland: A Field Study Using Treated Wastewater
Water 2017, 9(6), 449; doi:10.3390/w9060449
Received: 25 April 2017 / Revised: 7 June 2017 / Accepted: 12 June 2017 / Published: 21 June 2017
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Abstract
In the present study, a mixture of treated wastewater and surface water was used to rewet a degraded fen peatland site during a three-year rewetting experiment. We studied the behavior and effects of micropollutants by means of hydrological, physico-chemical, microbiological and ecotoxicological monitoring.
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In the present study, a mixture of treated wastewater and surface water was used to rewet a degraded fen peatland site during a three-year rewetting experiment. We studied the behavior and effects of micropollutants by means of hydrological, physico-chemical, microbiological and ecotoxicological monitoring. The highest concentrations of micropollutants in the treated wastewater were found for the pharmaceuticals carbamazepine and diclofenac, some metabolites, the sweetener acesulfame, tolyl- and benzotriazole and diatrizoate. In the underlying, shallow groundwater where treated wastewater application for rewetting had been expected to have the greatest impact due to seeping and evapotranspiration processes, only a sporadic occurrence of micropollutants was found. The influence of dilution by groundwater movements was examined by applying a geohydrological model. The sorption of micropollutants onto the peaty soil also played a role, as found for carbamazepine. Further processes such as photolysis, microbial decay under low redox conditions and plant uptake can be assumed to be relevant for the removal of many substances. Ecotoxicity tests with the soil before and after rewetting did not indicate any negative impact on the soil habitat quality by wastewater application, but clearly pointed at ecotoxicologically relevant geogenic arsenic concentrations at the study site. Although a positive effect on receiving surface water systems is expected if wastewater is applied on land instead of discharged to water bodies, the rewetted soil may turn into a sink for micropollutants in the long term. Hence, the findings of the present field study encourage further investigations in order to identify the governing processes in the elimination of micropollutants in rewetted peatlands flooded with treated wastewater. Full article
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Open AccessArticle Application of GIS-Interval Rough AHP Methodology for Flood Hazard Mapping in Urban Areas
Water 2017, 9(6), 360; doi:10.3390/w9060360
Received: 26 February 2017 / Revised: 4 May 2017 / Accepted: 18 May 2017 / Published: 24 May 2017
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Abstract
Floods are natural disasters with significant socio-economic consequences. Urban areas with uncontrolled urban development, rapid population growth, an unregulated municipal system and an unplanned change of land use belong to the highly sensitive areas where floods cause devastating economic and social losses. The
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Floods are natural disasters with significant socio-economic consequences. Urban areas with uncontrolled urban development, rapid population growth, an unregulated municipal system and an unplanned change of land use belong to the highly sensitive areas where floods cause devastating economic and social losses. The aim of this paper is to present a reliable GIS multi-criteria methodology for hazard zones’ mapping of flood-prone areas in urban areas. The proposed methodology is based on the combined application of geographical information systems (GIS) and multi-criteria decision analysis (MCDA). The methodology considers six factors that are relevant to the hazard of flooding in urban areas: the height, slope, distance to the sewage network, the distance from the water surface, the water table and land use. The expert evaluation takes into account the nature and severity of observed criteria, and it is tested using three scenarios: the modalities of the analytic hierarchy process (AHP). The first of them uses a new approach to the exploitation of uncertainty in the application of the AHP technique, the interval rough numbers (IR’AHP). The second one uses the fuzzy technique for the exploitation of uncertainty with the AHP method (F’AHP), and the third scenario contemplates the use of the traditional (crisp) AHP method. The proposed methodology is demonstrated in Palilula Municipality, Belgrade, Serbia. In the last few decades, Palilula Municipality has been repeatedly devastated by extreme flood events. These floods severely affected the transportation networks and other infrastructure. Historical flood inundation data have been used in the validation process. The final urban flood hazard map proves a satisfactory agreement between the flood hazard zones and the spatial distribution of historical floods that happened in the last 58 years. The results indicate that the scenario in which the IR’AHP methodology is used provides the highest level of compatibility with historical data on floods. The produced map showed that the areas of very high flood hazard are located on the left Danube River bank. These areas are characterized by lowland morphology, gentle slope, sewage network, expansion of impermeable locations and intense urbanization. The proposed GIS-IR’AHP methodology and the results of this study provide a good basis for developing a system of flood hazard management in urban areas and can be successfully used for spatial city development policy. Full article
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Open AccessFeature PaperArticle Shoreline Response to a Sequence of Typhoon and Monsoon Events
Water 2017, 9(6), 364; doi:10.3390/w9060364
Received: 11 April 2017 / Revised: 16 May 2017 / Accepted: 18 May 2017 / Published: 23 May 2017
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Abstract
Shoreline continuously adapts to changing multi-scale wave forcing. This study investigates the shoreline evolution of tropical beaches exposed to monsoon events and storms with a case study in Vietnam, facing the South China Sea, over the particularly active 2013–2014 season, including the Cat-5
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Shoreline continuously adapts to changing multi-scale wave forcing. This study investigates the shoreline evolution of tropical beaches exposed to monsoon events and storms with a case study in Vietnam, facing the South China Sea, over the particularly active 2013–2014 season, including the Cat-5 Haiyan typhoon. Our continuous video observations show for the first time that long-lasting monsoon events have more persistent impact (longer beach recovery phase) than typhoons. Using a shoreline equilibrium model, we estimate that the seasonal shoreline behavior is driven by the envelope of intra-seasonal events rather than monthly-averaged waves. Finally, the study suggests that the interplay between intra-seasonal event intensity and duration on the one hand and recovery conditions on the other might be of key significance. Their evolution in a variable or changing climate should be considered. Full article
(This article belongs to the Special Issue Sediment Transport in Coastal Waters)
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Open AccessArticle Study of the Removal of Aniline from Wastewater via MEUF Using Mixed Surfactants
Water 2017, 9(6), 365; doi:10.3390/w9060365
Received: 15 April 2017 / Revised: 10 May 2017 / Accepted: 19 May 2017 / Published: 23 May 2017
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Abstract
In this paper, the anionic surfactant sodium dodecyl sulfate (SDS) and the bio-surfactant rhamnolipid are mixed to achieve micellar-enhanced ultrafiltration, and the associated aniline removal efficiency is investigated. The impacts of five factors, including the mixing ratio of the SDS concentration to the
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In this paper, the anionic surfactant sodium dodecyl sulfate (SDS) and the bio-surfactant rhamnolipid are mixed to achieve micellar-enhanced ultrafiltration, and the associated aniline removal efficiency is investigated. The impacts of five factors, including the mixing ratio of the SDS concentration to the rhamnolipid concentration, the pH, the salinity, the operating pressure, and the aniline concentration in the feed solution, on the aniline rejection and the membrane permeation flux are explored. The aniline rejection mechanism of the rhamnolipid mixture surfactant is analyzed. This study shows that the effect of these factors on the aniline rejection is in the order of pH > mixing ratio > operating pressure > aniline concentration > salinity; the factors that affect the membrane permeation flux are in the order of mixing ratio > operating pressure > salinity > pH > aniline concentration. Under the optimal test conditions (i.e., SDS:rhamnolipid = 8:2, pH = 5, salinity = 250 mmol/L, operating pressure = 3.5 bar, aniline concentration = 1.5 mM), the verification test results showed an aniline rejection of 78.36%. Full article
(This article belongs to the Special Issue Modeling of Water Systems)
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Open AccessArticle Surface Water Monitoring within Cambodia and the Vietnamese Mekong Delta over a Year, with Sentinel-1 SAR Observations
Water 2017, 9(6), 366; doi:10.3390/w9060366
Received: 24 March 2017 / Revised: 17 May 2017 / Accepted: 19 May 2017 / Published: 23 May 2017
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Abstract
This study presents a methodology to detect and monitor surface water with Sentinel-1 Synthetic Aperture Radar (SAR) data within Cambodia and the Vietnamese Mekong Delta. It is based on a neural network classification trained on Landsat-8 optical data. Sensitivity tests are carried out
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This study presents a methodology to detect and monitor surface water with Sentinel-1 Synthetic Aperture Radar (SAR) data within Cambodia and the Vietnamese Mekong Delta. It is based on a neural network classification trained on Landsat-8 optical data. Sensitivity tests are carried out to optimize the performance of the classification and assess the retrieval accuracy. Predicted SAR surface water maps are compared to reference Landsat-8 surface water maps, showing a true positive water detection of ∼90% at 30 m spatial resolution. Predicted SAR surface water maps are also compared to floodability maps derived from high spatial resolution topography data. Results show high consistency between the two independent maps with 98% of SAR-derived surface water located in areas with a high probability of inundation. Finally, all available Sentinel-1 SAR observations over the Mekong Delta in 2015 are processed and the derived surface water maps are compared to corresponding MODIS/Terra-derived surface water maps at 500 m spatial resolution. Temporal correlation between these two products is very high (99%) with very close water surface extents during the dry season when cloud contamination is low. This study highlights the applicability of the Sentinel-1 SAR data for surface water monitoring, especially in a tropical region where cloud cover can be very high during the rainy seasons. Full article
(This article belongs to the Special Issue The Use of Remote Sensing in Hydrology)
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Open AccessArticle Modeling the Multi-Seasonal Link between the Hydrodynamics of a Reservoir and Its Hydropower Plant Operation
Water 2017, 9(6), 367; doi:10.3390/w9060367
Received: 9 January 2017 / Revised: 10 May 2017 / Accepted: 18 May 2017 / Published: 24 May 2017
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Abstract
The hydrodynamics of many hydropower reservoirs are controlled by the operation of their power plant, but the associated water quality impact is often poorly understood. In particular, significant hydropeaking operations by hydropower plants affect not only the downstream ecosystem but also the reservoir
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The hydrodynamics of many hydropower reservoirs are controlled by the operation of their power plant, but the associated water quality impact is often poorly understood. In particular, significant hydropeaking operations by hydropower plants affect not only the downstream ecosystem but also the reservoir water temperature. This paper contributes to understanding that link. For this, we coupled a hydrodynamic model (Estuary, Lake and Coastal Ocean Model, ELCOM) to a grid-wide power system scheduling model. In a case study (Rapel, Chile), we observe the behavior of variables related to the flow regime and water quality (including sub-daily hydrologic alteration, seasonal and sub-daily thermal pollution of the downstream river, and vertical mixing in the reservoir). Additionally, we evaluate how environmental constraints (ECs) can improve the conditions for a wet, normal and dry water-type year. We found that the unconstrained operation produces a strong sub-daily hydrologic alteration as well as an intense thermal pollution of the outflow. We show that these effects can clearly be avoided when implementing ECs. The current (unconstrained) vertical mixing makes the reservoir susceptible to algae blooms. Implementing ECs may intensify the stratification in the reservoir near the dam in some scenarios. The grid-wide economic cost of Rapel’s ECs is a modest 0.3%. Full article
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Open AccessArticle Optimizing Sediment Diversion Operations: Working Group Recommendations for Integrating Complex Ecological and Social Landscape Interactions
Water 2017, 9(6), 368; doi:10.3390/w9060368
Received: 11 April 2017 / Revised: 11 May 2017 / Accepted: 11 May 2017 / Published: 24 May 2017
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Abstract
Future conditions of coastal Louisiana are highly uncertain due to the dynamic nature of deltas, climate change, tropical storms, and human reliance on natural resources and ecosystem services. Managing a system in which natural and socio-economic components are highly integrated is inherently difficult.
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Future conditions of coastal Louisiana are highly uncertain due to the dynamic nature of deltas, climate change, tropical storms, and human reliance on natural resources and ecosystem services. Managing a system in which natural and socio-economic components are highly integrated is inherently difficult. Sediment diversions are a unique restoration tool that would reconnect the Mississippi River to its deltaic plain to build and sustain land. Diversions are innately adaptable as operations can be modified over time. An expert working group was formed to explore how various operational strategies may affect the complex interactions of coastal Louisiana’s ecological and social landscape and provide preliminary recommendations for further consideration and research. For example, initial operations should be gradually increased over 5 to 10 years to facilitate the development of a distributary channel network, reduce flood risk potential to communities, limit erosion of adjacent marshes and reduce stress to vegetation and fish and wildlife species. Diversions should operate over winter peaks to capture the highest sediment concentration, reduce vegetation loss while dormant, and reduce detrimental effects to fish and wildlife. Operations during the spring/summer should occur over shorter periods to capture the highest sediment load during the rising limb of the flood peak and minimize impacts to the ecosystem. Operational strategies should strive to build and sustain as much of the coastal landscape as possible while also balancing the ecosystem and community needs. Full article
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Open AccessArticle Assessing the Integration of Wetlands along Small European Waterways to Address Diffuse Nitrate Pollution
Water 2017, 9(6), 369; doi:10.3390/w9060369
Received: 31 March 2017 / Revised: 16 May 2017 / Accepted: 22 May 2017 / Published: 24 May 2017
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Abstract
Nitrate concentrations in numerous European fresh watercourses have decreased due to end-of-pipe measures towards manure and fertilization management, but fail to meet the environmental objectives. The implementation of complementary measures to attenuate diffuse nitrate pollution in densely populated regions characterised by limited available
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Nitrate concentrations in numerous European fresh watercourses have decreased due to end-of-pipe measures towards manure and fertilization management, but fail to meet the environmental objectives. The implementation of complementary measures to attenuate diffuse nitrate pollution in densely populated regions characterised by limited available area has been barely studied. To tackle this issue, this study evaluates the feasibility of integrating Constructed Wetlands (CWs) along waterways as a promising tool to facilitate compliance with the nitrate regulations. The aim is to calculate the required area of land alongside a specific watercourse to integrate CWs to reduce nitrate concentrations consistently below the 11.3 and 5.65 mgNO3-N/L levels, according to the Nitrates Directive and the Flemish Environmental Regulations. Nitrate-nitrogen removal efficiencies achieved at case study CWs were compared and validated with reported values to estimate the needed wetland areas. In addition, the removal efficiencies and areas needed to meet the standards were calculated via the kinetic model by Kadlec and Knight. The predicted areas by both methods indicated that CWs of 1.4–3.4 ha could be implemented in certain regions, such as Flanders (Belgium), with restricted available land. To conclude, three designs for ICWs (Integrated Constructed Wetlands) are proposed and evaluated, assessing the feasibility of their implementation. Full article
(This article belongs to the Special Issue Treatment Wetlands for Nutrient Removal)
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Open AccessArticle The Critical Depth of Freeze-Thaw Soil under Different Types of Snow Cover
Water 2017, 9(6), 370; doi:10.3390/w9060370
Received: 17 February 2017 / Revised: 19 May 2017 / Accepted: 22 May 2017 / Published: 25 May 2017
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Abstract
Snow cover is the most common upper boundary condition influencing the soil freeze-thaw process in the black soil farming area of northern China. Snow is a porous dielectric cover, and its unique physical properties affect the soil moisture diffusion, heat conduction, freezing rate
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Snow cover is the most common upper boundary condition influencing the soil freeze-thaw process in the black soil farming area of northern China. Snow is a porous dielectric cover, and its unique physical properties affect the soil moisture diffusion, heat conduction, freezing rate and other variables. To understand the spatial distribution of the soil water-heat and the variable characteristics of the critical depth of the soil water and heat, we used field data to analyze the freezing rate of soil and the extent of variation in soil water-heat in a unit soil layer under bare land (BL), natural snow (NS), compacted snow (CS) and thick snow (TS) treatments. The critical depth of the soil water and heat activity under different snow covers were determined based on the results of the analysis, and the variation fitting curve of the difference sequences on the soil temperature and water content between different soil layers and the surface 5-cm soil layer were used to verify the critical depth. The results were as follows: snow cover slowed the rate of soil freezing, and the soil freezing rate under the NS, CS and TS treatments decreased by 0.099 cm/day, 0.147 cm/day and 0.307 cm/day, respectively, compared with that under BL. In addition, the soil thawing time was delayed, and the effect was more significant with increased snow cover. During freeze-thaw cycles, the extent of variation in the water and heat time series in the shallow soil was relatively large, while there was less variation in the deep layer. There was a critical stratum in the vertical surface during hydrothermal migration, wherein the critical depth of soil water and heat change gradually increased with increasing snow cover. The variance in differences between the surface layer and both the soil water and heat in the different layers exhibited “steady-rising-steady” behavior, and the inflection point of the curve is the critical depth of soil freezing and thawing. This critical layer is a demarcation point between frozen soil and non-frozen soil, delineating the boundary between soil water and heat migration and non-migration. Furthermore, with increasing snow cover thickness and increasing density, the critical depth gradually increased. Full article
(This article belongs to the Special Issue Water-Soil-Vegetation Dynamic Interactions in Changing Climate)
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Open AccessFeature PaperArticle Improving the Viability of Stormwater Harvesting through Rudimentary Real Time Control
Water 2017, 9(6), 371; doi:10.3390/w9060371
Received: 27 March 2017 / Revised: 12 May 2017 / Accepted: 22 May 2017 / Published: 25 May 2017
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Abstract
Stormwater Harvesting (SWH) to alleviate water scarcity is often hindered by the lack of suitable available storage in urban areas. This research aimed to discover an economically viable strategy of storing runoff in existing stormwater ponds with the assistance of rudimentary Real Time
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Stormwater Harvesting (SWH) to alleviate water scarcity is often hindered by the lack of suitable available storage in urban areas. This research aimed to discover an economically viable strategy of storing runoff in existing stormwater ponds with the assistance of rudimentary Real Time Control (RTC) techniques to increase the effective storage capacity. The Diep River sub-catchment situated in the southern suburbs of Cape Town, South Africa, that has several stormwater ponds that were largely constructed for the purposes of flood mitigation, was used as a case study. Six SWH scenarios utilising three distinct RTC strategies coupled with two alternative water demand alternatives were simulated with the aid of 10 years’ of historical rainfall data with a view to determining the unit cost of supplying selected developments with non-potable water. The use of RTC to increase the effective storage of the ponds was shown to improve the volumetric yield without significantly impairing the flood mitigation provided by the system at a cost that was comparable to what the local residents were already paying for potable water. This finding is important as it suggests a cost-effective way of overcoming one of the greatest limitations associated with stormwater harvesting. Full article
(This article belongs to the Special Issue Advances on Urban Stormwater Harvesting Strategies)
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Open AccessArticle Evaluation and Inter-Comparison of Satellite Soil Moisture Products Using In Situ Observations over Texas, U.S.
Water 2017, 9(6), 372; doi:10.3390/w9060372
Received: 1 March 2017 / Revised: 10 May 2017 / Accepted: 18 May 2017 / Published: 25 May 2017
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Abstract
The main goal of this study was to evaluate four major remote sensing soil moisture (SM) products over the state of Texas. These remote sensing products are: (i) the Advanced Microwave Scanning Radiometer—Earth Observing System (AMSR-E) (2002–September 2011); (ii) the Soil Moisture Ocean
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The main goal of this study was to evaluate four major remote sensing soil moisture (SM) products over the state of Texas. These remote sensing products are: (i) the Advanced Microwave Scanning Radiometer—Earth Observing System (AMSR-E) (2002–September 2011); (ii) the Soil Moisture Ocean Salinity system (SMOS, 2010–present); (iii) AMSR2 (2012–present); and (iv) the Soil Moisture Active Passive system (SMAP, 2015–present). The quality of the generated SM data is influenced by the accuracy and precision of the sensors and the retrieval algorithms used in processing raw data. Therefore, it is important to evaluate the quality of these satellite SM products using in situ measurements and/or by inter-comparing their data during overlapping periods. In this study, these two approaches were used where we compared each satellite SM product to in situ soil moisture measurements and we also conducted an inter-comparison of the four satellite SM products at 15 different locations in Texas over six major land cover types (cropland, shrub, grassland, forest, pasture and developed) and eight climate zones along with in situ SM data from 15 Mesonet, USCRN and USDA-NRCS Scan stations. Results show that SM data from SMAP had the best correlation coefficients range from 0.37 to 0.92 with in situ measurements among the four tested satellite surface SM products. On the other hand, SM data from SMOS, AMSR2 and AMSR-E had moderate to low correlation coefficients ranges with in situ data, respectively, from 0.24–0.78, 0.07–0.62 and 0.05–0.52. During the overlapping periods, average root mean square errors (RMSEs) of the correlations between in situ and each satellite data were 0.13 (AMSR-E) and 0.13 (SMOS) cm3/cm3 (2010–2011), 0.16 (AMSR2) and 0.14 (SMOS) cm3/cm3 (2012–2016) and 0.13, 0.16, 0.14 (SMAP, AMSR2, SMOS) cm3/cm3 (2015–2016), respectively. Despite the coarser spatial resolution of all four satellite products (25–36 km), their SM measurements are considered reasonable and can be effectively used for different applications, e.g., flood forecasting, and drought prediction; however, further evaluation of each satellite product is recommended prior to its use in practical applications. Full article
(This article belongs to the Special Issue Remote Sensing of Soil Moisture)
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Open AccessArticle Effect of Sewage and Industrial Effluents on Bacterial and Archaeal Communities of Creek Sediments in the Taihu Basin
Water 2017, 9(6), 373; doi:10.3390/w9060373
Received: 9 March 2017 / Revised: 5 May 2017 / Accepted: 16 May 2017 / Published: 25 May 2017
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Abstract
Different characteristics of wastewater have different effects on the diversity and abundance of bacteria and archaea in rivers. There are many creeks around Taihu Lake, and they receive a large volume of industrial wastewater and domestic sewage, which is discharged into these creeks,
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Different characteristics of wastewater have different effects on the diversity and abundance of bacteria and archaea in rivers. There are many creeks around Taihu Lake, and they receive a large volume of industrial wastewater and domestic sewage, which is discharged into these creeks, and finally into Taihu Lake. The present study determined Illumina reads (16S rRNA gene amplicons) to analyze the effects of industrial wastewater and domestic sewage on the bacterial and archaeal communities at the different sampling sites along two creeks. The bacterial and archaeal diversity of the creek receiving sewage was higher than that of the creek receiving industrial waste. Proteobacteria dominated the microbial communities of all samples in both creeks. Betaproteobacteria dominated in the sewage creek, and its abundance declined along the creek. Certain pollutant-resistant classes were more abundant at the site near to the pollution source of the industry creek (e.g., Epsilonproteobacteria and Flavobacteria). Halobacteria belonging to the phylum Euryarchaeota was the dominant archaea at all sites in both creeks, while Methanobacteria was more abundant in the industry creek. The bacterial community was more affected by the distance between the sampling site and the pollutant source than the archaeal community, indicating that bacterial diversity and abundance could be a good index to distinguish domestic and industrial pollution, especially when the main pollution sources are difficult to identify. Full article
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Open AccessFeature PaperArticle The Performance and Potentials of the CryoSat-2 SAR and SARIn Modes for Lake Level Estimation
Water 2017, 9(6), 374; doi:10.3390/w9060374
Received: 28 February 2017 / Revised: 5 May 2017 / Accepted: 19 May 2017 / Published: 25 May 2017
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Abstract
Over the last few decades, satellite altimetry has proven to be valuable for monitoring lake levels. With the new generation of altimetry missions, CryoSat-2 and Sentinel-3, which operate in Synthetic Aperture Radar (SAR) and SAR Interferometric (SARIn) modes, the footprint size is reduced
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Over the last few decades, satellite altimetry has proven to be valuable for monitoring lake levels. With the new generation of altimetry missions, CryoSat-2 and Sentinel-3, which operate in Synthetic Aperture Radar (SAR) and SAR Interferometric (SARIn) modes, the footprint size is reduced to approximately 300 m in the along-track direction. Here, the performance of these new modes is investigated in terms of uncertainty of the estimated water level from CryoSat-2 data and the agreement with in situ data. The data quality is compared to conventional low resolution mode (LRM) altimetry products from Envisat, and the performance as a function of the lake area is tested. Based on a sample of 145 lakes with areas ranging from a few to several thousand km 2 , the CryoSat-2 results show an overall superior performance. For lakes with an area below 100 km 2 , the uncertainty of the lake levels is only half of that of the Envisat results. Generally, the CryoSat-2 lake levels also show a better agreement with the in situ data. The lower uncertainty of the CryoSat-2 results entails a more detailed description of water level variations. Full article
(This article belongs to the Special Issue The Use of Remote Sensing in Hydrology)
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Open AccessArticle Water versus Wireless Coverage in Rural Mali: Links and Paradoxes
Water 2017, 9(6), 375; doi:10.3390/w9060375
Received: 20 March 2017 / Revised: 24 April 2017 / Accepted: 19 May 2017 / Published: 26 May 2017
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Abstract
Water and wireless coverage were evaluated in a rural commune of southern Mali. All improved water sources in the area were checked for operability, accessibility, and water quality, while wireless coverage was tested by means of smartphones, phone calls, and instant messaging applications.
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Water and wireless coverage were evaluated in a rural commune of southern Mali. All improved water sources in the area were checked for operability, accessibility, and water quality, while wireless coverage was tested by means of smartphones, phone calls, and instant messaging applications. Theoretical water coverage exceeded 82% of the total village surface area, thus beating the national and sub-Saharan African averages, but dropped to just 39% when considering only serviceable and contamination-free sources. In contrast, wireless coverage exceeded 90%. These outcomes highlight a triple paradox: (1) water from theoretically safe (i.e., improved) water sources is often unsafe to drink; (2) wireless access is better than water access even though water is essential for human survival and telecommunications are not; and (3) excellent Internet coverage does not help a large number of people, who lack the skills, devices, or need to access it. While telecommunications seem to be making inroads towards universal access faster than the water sector, a survey of water committees uncovered a hidden nexus between both resources, revealing that increased wireless access is actually contributing to underpin water coverage in a variety of ways. Full article
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Open AccessFeature PaperArticle Verification of Calculation Method Using Monte Carlo Method for Water Supply Demands of Office Building
Water 2017, 9(6), 376; doi:10.3390/w9060376
Received: 7 February 2017 / Revised: 18 May 2017 / Accepted: 19 May 2017 / Published: 26 May 2017
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Abstract
In Japan, there are four methods of calculating water supply demands for office buildings based on SHASE-S 206 and two methods based on the design standard of Ministry of Land, Infrastructure, Transport and Tourism (MLIT). However, these methods were found to produce overestimated
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In Japan, there are four methods of calculating water supply demands for office buildings based on SHASE-S 206 and two methods based on the design standard of Ministry of Land, Infrastructure, Transport and Tourism (MLIT). However, these methods were found to produce overestimated values when applied to recent sanitary fixtures with advanced water saving features. To cope with this problem, Murakawa’s Simulation for Water Consumption (MSWC), which utilizes the Monte Carlo method to calculate water usage dynamically has been developed. In this study, we evaluated the validity of MSWC on water consumption of an office building. Actual water consumption data were collected from a six story office building. Water consumption estimates calculated by the six conventional methods and MSWC were compared with the actual measurement values. Though the calculations based on the conventional methods significantly deviated from the actual measurement values, those made by MSWC closely resembled them. Full article
(This article belongs to the Special Issue Water Supply and Drainage for Sustainable Built Environment)
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Open AccessArticle Evaluation of the SMOS-Derived Soil Water Deficit Index as Agricultural Drought Index in Northeast of Brazil
Water 2017, 9(6), 377; doi:10.3390/w9060377
Received: 13 March 2017 / Revised: 27 April 2017 / Accepted: 24 May 2017 / Published: 27 May 2017
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Abstract
Northeast Brazil (NEB) has recently experienced one of its worst droughts in the last decades, with large losses on rainfed agriculture. Soil moisture is the main variable to monitor agricultural drought. The remote sensing approach for drought monitoring has been enriched with the
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Northeast Brazil (NEB) has recently experienced one of its worst droughts in the last decades, with large losses on rainfed agriculture. Soil moisture is the main variable to monitor agricultural drought. The remote sensing approach for drought monitoring has been enriched with the launch of the Soil Moisture and Ocean Salinity (SMOS) in November 2009 by European Space Agency (ESA). In this work, the Soil Water Deficit Index (SWDI) was calculated using the SMOS L2 soil moisture in the NEB. The SMOS-derived SWDI data (SWDIS) were evaluated against the atmospheric water deficit (AWD) calculated from in situ observations. Comparisons were made at seven-day and 0.25° scales, over the time-span of June 2010 to December 2013. It was found that the SWDIS has a reasonably good overall performance in terms of the drought-weeks detection (skill = 0.986) and capture of the upper soil moisture temporal dynamic (r = 0.652), implying that the SWDIS could be used to track agricultural droughts. Furthermore, SWDIS shows poor performance at sites located in mountains regions affected by severe droughts (−0.10 ≤ r ≤ 0.10). It is also noted that the vegetal cover/use, climate regime, and soil texture have little influence on the AWD-SWDIS coupling. Full article
(This article belongs to the Special Issue Drought Monitoring, Forecasting, and Risk Assessment)
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Open AccessArticle A Stochastic Multi-Objective Chance-Constrained Programming Model for Water Supply Management in Xiaoqing River Watershed
Water 2017, 9(6), 378; doi:10.3390/w9060378
Received: 23 March 2017 / Revised: 24 May 2017 / Accepted: 24 May 2017 / Published: 27 May 2017
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Abstract
In this paper, a stochastic multi-objective chance-constrained programming model (SMOCCP) was developed for tackling the water supply management problem. Two objectives were included in this model, which are the minimization of leakage loss amounts and total system cost, respectively. The traditional SCCP model
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In this paper, a stochastic multi-objective chance-constrained programming model (SMOCCP) was developed for tackling the water supply management problem. Two objectives were included in this model, which are the minimization of leakage loss amounts and total system cost, respectively. The traditional SCCP model required the random variables to be expressed in the normal distributions, although their statistical characteristics were suitably reflected by other forms. The SMOCCP model allows the random variables to be expressed in log-normal distributions, rather than general normal form. Possible solution deviation caused by irrational parameter assumption was avoided and the feasibility and accuracy of generated solutions were ensured. The water supply system in the Xiaoqing River watershed was used as a study case for demonstration. Under the context of various weight combinations and probabilistic levels, many types of solutions are obtained, which are expressed as a series of transferred amounts from water sources to treated plants, from treated plants to reservoirs, as well as from reservoirs to tributaries. It is concluded that the SMOCCP model could reflect the sketch of the studied region and generate desired water supply schemes under complex uncertainties. The successful application of the proposed model is expected to be a good example for water resource management in other watersheds. Full article
(This article belongs to the Special Issue Modeling of Water Systems)
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Open AccessArticle Implementing the Prepaid Smart Meter System for Irrigated Groundwater Production in Northern China: Status and Problems
Water 2017, 9(6), 379; doi:10.3390/w9060379
Received: 10 March 2017 / Revised: 22 May 2017 / Accepted: 23 May 2017 / Published: 28 May 2017
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Abstract
To reduce the gap between groundwater demand and supply caused by agricultural groundwater over-exploitation, the Prepaid Smart Meter System (PSMS) is being strongly implemented by the Chinese government in northern China. This study reports the analysis and results of PSMS field surveys in
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To reduce the gap between groundwater demand and supply caused by agricultural groundwater over-exploitation, the Prepaid Smart Meter System (PSMS) is being strongly implemented by the Chinese government in northern China. This study reports the analysis and results of PSMS field surveys in six typical provinces in northern China as well as domestic literature reviews. Based on the architecture and implementation policies of the system, the implementation differences between areas and the influencing factors were analyzed, particularly the acknowledgment of farmers, the installation proportion of tube wells, the social benefits. Great achievements have been gained in the implementation, and the management targets have been achieved, including accurately metering overall irrigation groundwater production, assisting in the total amount control and quota management, reducing groundwater exploitation, and improving water use efficiency. However, shortcomings remain in the implementation process, such as single initial investment channels, imperfect policy system construction, a lack of retrieving and analyzing data, and the unbalanced development between areas. Countermeasures and suggestions for these problems are discussed in this article. Full article
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Open AccessArticle Effects of Dredging and Lanthanum-Modified Clay on Water Quality Variables in an Enclosure Study in a Hypertrophic Pond
Water 2017, 9(6), 380; doi:10.3390/w9060380
Received: 21 March 2017 / Revised: 19 May 2017 / Accepted: 19 May 2017 / Published: 27 May 2017
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Abstract
An enclosure experiment was conducted between July and September 2009 to compare the effectiveness of a phosphate fixative, the lanthanum-modified bentonite clay Phoslock® (LMB), dredging, and their combination in controlling eutrophication in a hypertrophic urban pond in Heesch, The Netherlands. In total,
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An enclosure experiment was conducted between July and September 2009 to compare the effectiveness of a phosphate fixative, the lanthanum-modified bentonite clay Phoslock® (LMB), dredging, and their combination in controlling eutrophication in a hypertrophic urban pond in Heesch, The Netherlands. In total, 25 water quality variables were monitored. Multivariate analysis revealed that the combination LMB-treated and dredged enclosures deviated most from the pond (reference) and the controls, and showed the strongest eutrophication reduction. Overall, dredging significantly increased transparency, lowered turbidity, and improved the oxygen conditions in the enclosures compared to non-dredged ones. Nonetheless, one dredged enclosure deviated dramatically from the others, which might reflect methodological issues with dredging. The LMB treatment appeared to be less effective at mitigating eutrophication than dredging, and phosphate concentrations even increased during the experiment in the LMB-treated enclosures. Chemical equilibrium modeling suggested that humic substances could have formed complexes with lanthanum (La) from the LMB, rendering it unavailable for intercepting P over the course of the enclosure experiment. Residual lanthanum concentrations in combination dredging and LMB treatments exceeded the Dutch standard 10-fold. Total zooplankton abundance, and particularly Cladocera, increased in all enclosures over the course of the experiment. The limited effect of LMB in the enclosure experiment and the violation of the Dutch La standard when combined with dredging disqualify LMB as an intervention agent in the restoration of the pond. Full article
(This article belongs to the Special Issue Water Quality Monitoring and Modeling in Lakes)
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Open AccessFeature PaperArticle Optimising Fuzzy Neural Network Architecture for Dissolved Oxygen Prediction and Risk Analysis
Water 2017, 9(6), 381; doi:10.3390/w9060381
Received: 30 March 2017 / Revised: 17 May 2017 / Accepted: 24 May 2017 / Published: 28 May 2017
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Abstract
A fuzzy neural network method is proposed to predict minimum daily dissolved oxygen concentration in the Bow River, in Calgary, Canada. Owing to the highly complex and uncertain physical system, a data-driven and fuzzy number based approach is preferred over traditional approaches. The
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A fuzzy neural network method is proposed to predict minimum daily dissolved oxygen concentration in the Bow River, in Calgary, Canada. Owing to the highly complex and uncertain physical system, a data-driven and fuzzy number based approach is preferred over traditional approaches. The inputs to the model are abiotic factors, namely water temperature and flow rate. An approach to select the optimum architecture of the neural network is proposed. The total uncertainty of the system is captured in the fuzzy numbers weights and biases of the neural network. Model predictions are compared to the traditional, non-fuzzy approach, which shows that the proposed method captures more low DO events. Model output is then used to quantify the risk of low DO for different conditions. Full article
(This article belongs to the Special Issue Modeling of Water Systems)
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Open AccessArticle Analysis of Pneumatic Pressure Vibration Affected by Connecting WCs and Discharge Load Types
Water 2017, 9(6), 382; doi:10.3390/w9060382
Received: 7 February 2017 / Revised: 24 May 2017 / Accepted: 26 May 2017 / Published: 29 May 2017
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Abstract
In the design of a drainage system, allowable drainage flow quantity (drainage capability) is defined for each pipe diameter in order to prevent seal water from breaking. In Japan, SHASE-S 218 (Heating, Air-Conditioning, and Sanitary Standard) stipulates the evaluation standard for drainage capability.
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In the design of a drainage system, allowable drainage flow quantity (drainage capability) is defined for each pipe diameter in order to prevent seal water from breaking. In Japan, SHASE-S 218 (Heating, Air-Conditioning, and Sanitary Standard) stipulates the evaluation standard for drainage capability. Regardless of the presence or absence of connection of the traps, there are two types of test criteria. One is that pressure in the pipe should fall within ±400 Pa, and the other is that the seal loss should be less than 25 mm. Nevertheless, recent studies revealed that the connecting of traps attenuates pneumatic pressure in pipes and causes a tendency of the power spectrum distribution to change. This phenomenon may be attributable to the fact that seal water vibration is a response phenomenon to pneumatic pressure vibration, and that they affect each other. In view of this, we conducted discharge experiments based on SHASE-S 218 with and without traps (including water-saving toilet bowl (hereinafter, referred to as “WC”) using a real size drainage experimental system to clarify how the connection of WC might influence pneumatic pressure. We revealed that as the number of toilets connected to the drainage system increases, the pneumatic pressure and seal water loss decrease. Full article
(This article belongs to the Special Issue Water Supply and Drainage for Sustainable Built Environment)
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Open AccessArticle An Analysis of Terrestrial and Aquatic Environmental Controls of Riverine Dissolved Organic Carbon in the Conterminous United States
Water 2017, 9(6), 383; doi:10.3390/w9060383
Received: 20 February 2017 / Revised: 25 May 2017 / Accepted: 25 May 2017 / Published: 29 May 2017
PDF Full-text (1814 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Analyses of environmental controls on riverine carbon fluxes are critical for improved understanding of the mechanisms regulating carbon cycling along the terrestrial-aquatic continuum. Here, we compile and analyze riverine dissolved organic carbon (DOC) concentration data from 1402 United States Geological Survey (USGS) gauge
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Analyses of environmental controls on riverine carbon fluxes are critical for improved understanding of the mechanisms regulating carbon cycling along the terrestrial-aquatic continuum. Here, we compile and analyze riverine dissolved organic carbon (DOC) concentration data from 1402 United States Geological Survey (USGS) gauge stations to examine the spatial variability and environmental controls of DOC concentrations in the United States (U.S.) surface waters. DOC concentrations exhibit high spatial variability in the U.S., with an average of 6.42 ± 6.47 mg C/L (Mean ± Standard Deviation). High DOC concentrations occur in the Upper Mississippi River basin and the southeastern U.S., while low concentrations are mainly distributed in the western U.S. Soil properties such as soil organic matter, soil water content, and soil sand content mainly show positive correlations with DOC concentrations; forest and shrub land have positive correlations with DOC concentrations, but urban area and cropland demonstrate negative impacts; and total instream phosphorus and dam density correlate positively with DOC concentrations. Notably, the relative importance of these environmental controls varies substantially across major U.S. water resource regions. In addition, DOC concentrations and environmental controls also show significant variability from small streams to large rivers. In sum, our results reveal that general multi-linear regression of twenty environmental factors can partially explain (56%) the DOC concentration variability. This study also highlights the complexity of the interactions among these environmental factors in determining DOC concentrations, thus calls for processes-based, non-linear methodologies to constrain uncertainties in riverine DOC cycling. Full article
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Open AccessArticle Sensitivity of Calibrated Parameters and Water Resource Estimates on Different Objective Functions and Optimization Algorithms
Water 2017, 9(6), 384; doi:10.3390/w9060384
Received: 31 March 2017 / Revised: 21 May 2017 / Accepted: 24 May 2017 / Published: 30 May 2017
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Abstract
The successful application of hydrological models relies on careful calibration and uncertainty analysis. However, there are many different calibration/uncertainty analysis algorithms, and each could be run with different objective functions. In this paper, we highlight the fact that each combination of optimization algorithm-objective
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The successful application of hydrological models relies on careful calibration and uncertainty analysis. However, there are many different calibration/uncertainty analysis algorithms, and each could be run with different objective functions. In this paper, we highlight the fact that each combination of optimization algorithm-objective functions may lead to a different set of optimum parameters, while having the same performance; this makes the interpretation of dominant hydrological processes in a watershed highly uncertain. We used three different optimization algorithms (SUFI-2, GLUE, and PSO), and eight different objective functions (R2, bR2, NSE, MNS, RSR, SSQR, KGE, and PBIAS) in a SWAT model to calibrate the monthly discharges in two watersheds in Iran. The results show that all three algorithms, using the same objective function, produced acceptable calibration results; however, with significantly different parameter ranges. Similarly, an algorithm using different objective functions also produced acceptable calibration results, but with different parameter ranges. The different calibrated parameter ranges consequently resulted in significantly different water resource estimates. Hence, the parameters and the outputs that they produce in a calibrated model are “conditioned” on the choices of the optimization algorithm and objective function. This adds another level of non-negligible uncertainty to watershed models, calling for more attention and investigation in this area. Full article
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Open AccessArticle Simulating the Fate and Transport of Coal Seam Gas Chemicals in Variably-Saturated Soils Using HYDRUS
Water 2017, 9(6), 385; doi:10.3390/w9060385
Received: 16 April 2017 / Revised: 11 May 2017 / Accepted: 22 May 2017 / Published: 30 May 2017
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Abstract
The HYDRUS-1D and HYDRUS (2D/3D) computer software packages are widely used finite element models for simulating the one-, and two- or three-dimensional movement of water, heat, and multiple solutes in variably-saturated media, respectively. While the standard HYDRUS models consider only the fate and
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The HYDRUS-1D and HYDRUS (2D/3D) computer software packages are widely used finite element models for simulating the one-, and two- or three-dimensional movement of water, heat, and multiple solutes in variably-saturated media, respectively. While the standard HYDRUS models consider only the fate and transport of individual solutes or solutes subject to first-order degradation reactions, several specialized HYDRUS add-on modules can simulate far more complex biogeochemical processes. The objective of this paper is to provide a brief overview of the HYDRUS models and their add-on modules, and to demonstrate possible applications of the software to the subsurface fate and transport of chemicals involved in coal seam gas extraction and water management operations. One application uses the standard HYDRUS model to evaluate the natural soil attenuation potential of hydraulic fracturing chemicals and their transformation products in case of an accidental release. By coupling the processes of retardation, first-order degradation and convective-dispersive transport of the biocide bronopol and its degradation products, we demonstrated how natural attenuation reduces initial concentrations by more than a factor of hundred in the top 5 cm of the soil. A second application uses the UnsatChem module to explore the possible use of coal seam gas produced water for sustainable irrigation. Simulations with different irrigation waters (untreated, amended with surface water, and reverse osmosis treated) provided detailed results regarding chemical indicators of soil and plant health, notably SAR, EC and sodium concentrations. A third application uses the HP1 module to analyze trace metal transport involving cation exchange and surface complexation sorption reactions in a soil leached with coal seam gas produced water following some accidental water release scenario. Results show that the main process responsible for trace metal migration in soil is complexation of naturally present trace metals with inorganic ligands such as (bi)carbonate that enter the soil upon infiltration with alkaline produced water. The examples were selected to show how users can tailor the required model complexity to specific needs, such as for rapid screening or risk assessments of various chemicals nder generic soil conditions, or for more detailed site-specific analyses of actual subsurface pollution problems. Full article
(This article belongs to the Special Issue Water and Solute Transport in Vadose Zone)
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Open AccessArticle Distribution and Removal of Nonylphenol Ethoxylates and Nonylphenol from Textile Wastewater—A Comparison of a Cotton and a Synthetic Fiber Factory in Vietnam
Water 2017, 9(6), 386; doi:10.3390/w9060386
Received: 16 March 2017 / Revised: 19 May 2017 / Accepted: 20 May 2017 / Published: 31 May 2017
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Abstract
The textile industry is a significant source of nonyphenol and their ethoxylates, which are suggested to be responsible for endocrine disruption in wildlife and humans. This study is a comparison of two conventional wastewater treatment processes in a cotton and a synthetic fiber
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The textile industry is a significant source of nonyphenol and their ethoxylates, which are suggested to be responsible for endocrine disruption in wildlife and humans. This study is a comparison of two conventional wastewater treatment processes in a cotton and a synthetic fiber factory in Vietnam, with regard to the distribution and removal of nonyphenol ethoxylates and nonyphenol throughout each process. Diverse trends in the distribution of nonyphenol ethoxylates in wastewater from factories, distinguished by their raw materials, could be revealed. Primary coagulation might not perfectly facilitate nitrification in the secondary activated sludge process regarding pH. Nevertheless, satisfactory removals were achieved during coagulation and activated sludge processes in both systems. The roles of long hydraulic retention times (21 and 16 h, respectively), low organic loadings (0.1 and 0.2 gCOD/gMLVSS.day, respectively), extended solids retention times (61 and 66 days, respectively), and mixed liquor suspended solids of greater than 2000 mg/L have been demonstrated. The findings provide evidence and a better understanding of nonyphenol ethoxylate and nonyphenol removal efficacy as well as influencing factors in Vietnamese textile wastewater treatment. The results are beneficial for the textile industry in Vietnam regarding investment decisions for wastewater treatment. Full article
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Open AccessArticle SWE-SPHysics Simulation of Dam Break Flows at South-Gate Gorges Reservoir
Water 2017, 9(6), 387; doi:10.3390/w9060387
Received: 7 April 2017 / Revised: 19 May 2017 / Accepted: 28 May 2017 / Published: 31 May 2017
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Abstract
This paper applied a Smoothed Particle Hydrodynamics (SPH) approach to solve Shallow Water Equations (SWEs) to study practical dam-break flows. The computational program is based on the open source code SWE-SPHysics, where a Monotone Upstream-centered Scheme for Conservation Laws (MUSCL) reconstruction method is
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This paper applied a Smoothed Particle Hydrodynamics (SPH) approach to solve Shallow Water Equations (SWEs) to study practical dam-break flows. The computational program is based on the open source code SWE-SPHysics, where a Monotone Upstream-centered Scheme for Conservation Laws (MUSCL) reconstruction method is used to improve the Riemann solution with Lax-Friedrichs flux. A virtual boundary particle method is applied to treat the solid boundary. The model is first tested on two benchmark collapses of water columns with the existence of downstream obstacle. Subsequently the model is applied to forecast a prototype dam-break flood, which might occur in South-Gate Gorges Reservoir area of Qinghai Province, China. It shows that the SWE-SPH modeling approach could provide a promising simulation tool for practical dam-break flows in engineering scale. Full article
(This article belongs to the Special Issue Modeling of Water Systems)
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Open AccessFeature PaperArticle The Rocky Path to Source Water Protection: A Cross-Case Analysis of Drinking Water Crises in Small Communities in Canada
Water 2017, 9(6), 388; doi:10.3390/w9060388
Received: 29 March 2017 / Revised: 19 May 2017 / Accepted: 25 May 2017 / Published: 1 June 2017
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Abstract
Source water protection (SWP) is increasingly seen as effective in reducing the incidence and extent of drinking water crises, yet its facilitation requires certain measures. Canada has one of the most decentralized water governance systems in the world. We sought to understand the
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Source water protection (SWP) is increasingly seen as effective in reducing the incidence and extent of drinking water crises, yet its facilitation requires certain measures. Canada has one of the most decentralized water governance systems in the world. We sought to understand the experience and impacts of drinking water crises at community and government levels in a decentralized context: the Canadian province of Newfoundland and Labrador through cross-case analysis. We selected our three study communities through a database of media reports in 2014 followed by invitations to community leaders. We used descriptive and qualitative methods, specifically structured interview schedules with both closed- and open-ended questions, and interviewed four community leaders and three provincial government officials. We used NVivo in data analysis, especially in the identification of themes. While government officials defined water crises largely in terms of SWP, this was not the same for communities, whose concern was mainly water access, specifically water shortages. Thus, while the prioritizing of SWP can be useful, the current focus on SWP has the potential to overlook aspects of water security, particularly in some rural and Indigenous communities in Canada. If we envision water security as a ladder representing a hierarchy of needs, some communities are too far down on the ladder to operationalize SWP because their water problems are more extreme. Full article
(This article belongs to the Special Issue Source Water Protection: State of the Art and Science)
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Open AccessFeature PaperArticle Effect of Organic Matter on Cr(VI) Removal from Groundwaters by Fe(II) Reductive Precipitation for Groundwater Treatment
Water 2017, 9(6), 389; doi:10.3390/w9060389
Received: 21 April 2017 / Revised: 25 May 2017 / Accepted: 27 May 2017 / Published: 1 June 2017
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Abstract
Due to its toxicity, Cr(VI) is undesirable in groundwater. Its chemical reduction to Cr(III) species, followed by precipitation is the most widely practiced treatment technique for the removal of Cr(VI) from polluted waters. The resulting Cr(III) species present low solubility, is much less
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Due to its toxicity, Cr(VI) is undesirable in groundwater. Its chemical reduction to Cr(III) species, followed by precipitation is the most widely practiced treatment technique for the removal of Cr(VI) from polluted waters. The resulting Cr(III) species present low solubility, is much less toxic, and can be subsequently removed either by precipitation, or by adsorption onto iron oxy-hydroxides and co-precipitation. The effects of several parameters, such as the pH value of water to be treated, the applied Fe(II) dose, and the presence of appropriate mineral surfaces, are well investigated and understood. However, the impact of the presence of humic acids (HAs) in this process has only been considered by rather few studies. The main aim of this study was to determine the effect of humic substances on Fe(II) reductive precipitation of Cr(VI) within a pH range relevant for drinking water treatment. Jar test experiments were performed, using artificial groundwater of defined composition and initial Cr(VI) concentration 100 μg/L, ferrous sulphate dosages 0.25–2 mg Fe(II)/L, and pH values 6.5–8. It was found that Cr(VI) and total chromium (Cr(total)) can be reliably removed in the absence of HAs in the tested pH range with the addition of Fe(II) dosage of 1 mg Fe(II)/L. Further on, the results indicated that the reduction of Cr(VI) is only slightly affected by the presence of HAs. However, increased residual total Cr concentrations were found at lower Fe(II) dosages and/or higher pH values. Additionally, the removal of the Cr(III) species formed during Cr(VI) reduction was strongly inhibited by the presence of HAs under the examined experimental conditions, since residual concentrations higher than 60 μg/L were determined. The results of this study will have implications to the ongoing discussion of a new, stricter, European Union regulation limit, regarding the presence of total chromium in drinking water. Full article
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Open AccessArticle A Study on Coastal Flooding and Risk Assessment under Climate Change in the Mid-Western Coast of Taiwan
Water 2017, 9(6), 390; doi:10.3390/w9060390
Received: 21 March 2017 / Revised: 26 April 2017 / Accepted: 22 May 2017 / Published: 1 June 2017
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Abstract
This study integrated coastal watershed models and combined them with a risk assessment method to develop a methodology to investigate the impact resulting from coastal disasters under climate change. The mid-western coast of Taiwan suffering from land subsidence was selected as the demonstrative
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This study integrated coastal watershed models and combined them with a risk assessment method to develop a methodology to investigate the impact resulting from coastal disasters under climate change. The mid-western coast of Taiwan suffering from land subsidence was selected as the demonstrative area for the vulnerability analysis based on the prediction of sea level rise (SLR), wave run-up, overtopping, and coastal flooding under the scenarios of the years from 2020 to 2039. Databases from tidal gauges and satellite images were used to analyze SLR using Ensemble Empirical Mode Decomposition (EEMD). Extreme wave condition and storm surge were estimated by numerical simulation using the Wind Wave Model (WWM) and the Princeton Ocean Model (POM). Coastal inundation was then simulated via the WASH123D watershed model. The risk map of study areas based on the analyses of vulnerability and disaster were established using the Analytic Hierarchy Process (AHP) technique. Predictions of sea level rise, the maximum wave condition, and storm surge under the scenarios of 2020 to 2039 are presented. The results indicate that the sea level at the mid-western coast of Taiwan will rise by an average of 5.8 cm, equivalent to a rising velocity of 2.8 mm/year. The analysis indicates that the Wuqi, Lukang, Mailiao, and Taixi townships are susceptive, low resistant and low resilient and reach the high-risk level. This assessment provides important information for creating an adaption policy for the mid-western coast of Taiwan. Full article
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Open AccessArticle Flood Simulations and Uncertainty Analysis for the Pearl River Basin Using the Coupled Land Surface and Hydrological Model System
Water 2017, 9(6), 391; doi:10.3390/w9060391
Received: 23 March 2017 / Revised: 24 May 2017 / Accepted: 28 May 2017 / Published: 1 June 2017
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Abstract
The performances of hydrological simulations for the Pearl River Basin in China were analysed using the Coupled Land Surface and Hydrological Model System (CLHMS). Three datasets, including East Asia (EA), high-resolution gauge satellite-merged China Merged Precipitation Analysis (CMPA)-Daily, and the Asian Precipitation Highly-Resolved
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The performances of hydrological simulations for the Pearl River Basin in China were analysed using the Coupled Land Surface and Hydrological Model System (CLHMS). Three datasets, including East Asia (EA), high-resolution gauge satellite-merged China Merged Precipitation Analysis (CMPA)-Daily, and the Asian Precipitation Highly-Resolved Observational Data Integration Towards Evaluation (APHRODITE) daily precipitation were used to drive the CLHMS model to simulate daily hydrological processes from 1998 to 2006. The results indicate that the precipitation data was the most important source of uncertainty in the hydrological simulation. The simulated streamflow driven by the CMPA-Daily agreed well with observations, with a Pearson correlation coefficient (PMC) greater than 0.70 and an index of agreement (IOA) similarity coefficient greater than 0.82 at Liuzhou, Shijiao, and Wuzhou Stations. Comparison of the Nash-Sutcliffe efficiency coefficient (NSE) shows that the peak flow simulation ability of CLHMS driven with the CMPA-Daily rainfall is relatively superior to that with the EA and APHRODITE datasets. The simulation results for the high-flow periods in 1998 and 2005 indicate that the CLHMS is promising for its future application in the flood simulation and prediction. Full article
(This article belongs to the Special Issue Modeling of Water Systems)
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Open AccessFeature PaperArticle European Rice Cropland Mapping with Sentinel-1 Data: The Mediterranean Region Case Study
Water 2017, 9(6), 392; doi:10.3390/w9060392
Received: 7 February 2017 / Revised: 5 May 2017 / Accepted: 26 May 2017 / Published: 1 June 2017
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Abstract
Rice farming is one of the most important activities in the agriculture sector, producing staple food for the majority of the world's growing population. Accurate and up-to-date assessment of the spatial distribution of rice cultivated area is a key information requirement of all
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Rice farming is one of the most important activities in the agriculture sector, producing staple food for the majority of the world's growing population. Accurate and up-to-date assessment of the spatial distribution of rice cultivated area is a key information requirement of all stakeholders including policy makers, rice farmers and consumers. Timely assessment with high precision is, e.g., crucial for water resource management, market prices control and during humanitarian food crisis. Recently, two Sentinel-1 (S-1) satellites carrying a C-band Synthetic Aperture Radar (SAR) sensor were launched by the European Space Agency (ESA) within the homework of the Copernicus program. The advanced data acquisition capabilities of S-1 provide a unique opportunity to monitor different land cover types at high spatial (20 m) and temporal (twice-weekly to biweekly) resolution. The objective of this research is to evaluate the applicability of an existing phenology-based classification method for continental-scale rice cropland mapping using S-1 backscatter time series. In this study, the S-1 images were collected during the rice growing season of 2015 covering eight selected European test sites situated in six Mediterranean countries. Due to the better rice classification capabilities of SAR cross-polarized measurement as compared to co-polarized data, S-1 cross-polarized (VH) data were used. Phenological parameters derived from the S-1 VH backscatter time series were used as an input to a knowledge-based decision-rule classifier in order to classify the input data into rice and non-rice areas. The classification results were evaluated using multiple regions of interest (ROIs) drawn from high-resolution optical remote sensing (SPOT 5) data and the European CORINE land cover (CLC 2012) product. An overall accuracy of more than 70% for all eight study sites was achieved. The S-1 based classification maps reveal much more details compared to the rice field class contained in the CLC 2012 product. These findings demonstrate the potential and feasibility of using S-1 VH data to develop an operational rice crop monitoring framework at the continental scale. Full article
(This article belongs to the Special Issue The Use of Remote Sensing in Hydrology)
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Open AccessArticle Water Use and Yield of Soybean under Various Irrigation Regimes and Severe Water Stress. Application of AquaCrop and SIMDualKc Models
Water 2017, 9(6), 393; doi:10.3390/w9060393
Received: 27 April 2017 / Revised: 25 May 2017 / Accepted: 28 May 2017 / Published: 1 June 2017
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Abstract
Data relative to two soybean seasons, several irrigation scheduling treatments, including moderate and severe deficit irrigation, and rain-fed cropping were used to parameterize and assess the performance of models AquaCrop and SIMDualKc, the latter combined with the Stewart’s yield model. SIMDualKc applies the
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Data relative to two soybean seasons, several irrigation scheduling treatments, including moderate and severe deficit irrigation, and rain-fed cropping were used to parameterize and assess the performance of models AquaCrop and SIMDualKc, the latter combined with the Stewart’s yield model. SIMDualKc applies the FAO56 dual crop coefficient approach for computing and partitioning evapotranspiration (ET) into actual crop transpiration (Tc act) and soil evaporation (Es), while AquaCrop uses an approach that depends on the canopy cover curve. The calibration-validations of models were performed by comparing observed and predicted soil water content (SWC) and grain yield. SIMDualKc showed good accuracy for SWC estimations, with normalized root mean square error (NRMSE) ≤ 7.6%. AquaCrop was less accurate, with NRMSE ≤ 9.2%. Differences between models regarding the water balance terms were notable, and the ET partition revealed a trend for under-estimation of Tc act by AquaCrop, mainly under severe water stress. Yield predictions with SIMDualKc-Stewart models produced NRMSE < 15% while predictions with AquaCrop resulted in NRMSE ≤ 23% due to under-estimation of Tc act, particularly for water stressed treatments. Results show the appropriateness of SIMDualKc to support irrigation scheduling and assessing impacts on yield when combined with Stewart’s model. Full article
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Open AccessArticle Vulnerability of Buildings on Coastal Dikes due to Wave Overtopping
Water 2017, 9(6), 394; doi:10.3390/w9060394
Received: 21 April 2017 / Revised: 19 May 2017 / Accepted: 26 May 2017 / Published: 2 June 2017
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Abstract
The vulnerability of buildings on coastal dikes due to overtopping wave impacts is difficult to assess. A method is developed in this paper to quantify the vulnerability of masonry buildings on a coastal dike exposed to wave overtopping. Using previous studies, the accidental
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The vulnerability of buildings on coastal dikes due to overtopping wave impacts is difficult to assess. A method is developed in this paper to quantify the vulnerability of masonry buildings on a coastal dike exposed to wave overtopping. Using previous studies, the accidental loads due to the extreme wave impacts are characterized. Using the approach from Eurocode 6, the strength of masonry buildings under these loads is assessed. Results from a case study in Belgium show that masonry buildings located 10–15 m away from the seafront would suffer from localized damage, such as windows being broken under a 1000 year storm. The building would collapse under a 10,000-year storm. The method can be used to assess the safety of existing buildings on coastal dikes and to design new buildings. Full article
Open AccessFeature PaperArticle LCA Methodology for the Quantification of the Carbon Footprint of the Integrated Urban Water System
Water 2017, 9(6), 395; doi:10.3390/w9060395
Received: 31 March 2017 / Revised: 23 May 2017 / Accepted: 25 May 2017 / Published: 2 June 2017
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Abstract
In integrated urban water systems, energy consumption, and consequently the amount of produced CO2, depends on many environmental, infrastructural, and management factors such as supply water quality, on which treatment complexity depends, urban area orography, water systems efficiency, and maintenance levels.
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In integrated urban water systems, energy consumption, and consequently the amount of produced CO2, depends on many environmental, infrastructural, and management factors such as supply water quality, on which treatment complexity depends, urban area orography, water systems efficiency, and maintenance levels. An important factor is related to the presence of significant water losses, which result in an increase in the supply volume and therefore a higher energy consumption for treatment and pumping, without effectively supplying users. The current European environmental strategy is committed to sustainable development by generating action plans to improve the environmental performance of products and services. The analysis of carbon footprints is considered one such improvement, allowing for the evaluation of the environmental impact of single production phases. Using this framework, the aim of the study is to apply a Life Cycle Assessment (LCA) methodology to quantify the carbon footprint of an overall integrated urban water system referring to ISO/TS 14067 (2013). This methodology uses an approach known as “cradle to grave” and presumes to conduct an objective assessment of product units, balancing energy, and matter flows along the production process. The methodology was applied to a real case study, i.e., the integrated urban water system of the Palermo metropolitan area in Sicily (Italy). Each process in the system was characterized and globally evaluated from the point of view of water loss, energy consumption, and CO2 production, and some mitigation strategies are proposed and evaluated to reduce the energy consumption and, consequently, the environmental impact of the system. Full article
(This article belongs to the Special Issue Synergies in Urban Water Infrastructure Modeling)
Open AccessArticle Soil Water and Phreatic Evaporation in Shallow Groundwater during a Freeze–Thaw Period
Water 2017, 9(6), 396; doi:10.3390/w9060396
Received: 12 March 2017 / Revised: 8 May 2017 / Accepted: 26 May 2017 / Published: 2 June 2017
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Abstract
The exchange between shallow groundwater and soil water is unusually strong during freeze-thaw periods. The purpose of this study is to determine the effect of four different groundwater table depths (GTDs) and two soil textures on soil water moisture migration and phreatic evaporation
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The exchange between shallow groundwater and soil water is unusually strong during freeze-thaw periods. The purpose of this study is to determine the effect of four different groundwater table depths (GTDs) and two soil textures on soil water moisture migration and phreatic evaporation during a freeze-thaw period using lysimeters. The results show that a high-moisture zone (HMZ) formed at a depth of 25–35 cm for sandy loam with a soil moisture content of 52%, while no obvious HMZ formed for fine sand when the GTD was 0.5 m. When the GTD was 2.0 m, a HMZ formed at a depth of 50–70 cm for sandy loam at the highest soil moisture content of 22%, while a HMZ formed at a depth of 60–80 cm for fine sand with a soil moisture content of 10%. The cumulative phreatic evaporation increased by a power function on freezing days during the freezing period. The total phreatic evaporation for sandy loam declined linearly with the increasing of GTD, and with the largest evaporation value of 73.6 mm for fine sand when the GTD was 1.0 m during the freeze-thaw period. The research would be significant for water resource assessment, the conversion of farmland water, and the prevention of saline land. Full article
Open AccessFeature PaperArticle Polymer Inclusion Membranes with Strip Dispersion
Water 2017, 9(6), 399; doi:10.3390/w9060399
Received: 13 March 2017 / Revised: 23 May 2017 / Accepted: 28 May 2017 / Published: 3 June 2017
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Abstract
The present work investigated the permeation of indium ions through a polymer inclusion membrane (PIM), prepared with cellulose triacetate (CTA) as the base polymer, tris(2-butoxyethyl) phosphate (TBEP) as the plasticizer and di-(2-ethylhexyl)phosphoric acid (D2EHPA) as the extractant. With 5 M HCl aqueous solution
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The present work investigated the permeation of indium ions through a polymer inclusion membrane (PIM), prepared with cellulose triacetate (CTA) as the base polymer, tris(2-butoxyethyl) phosphate (TBEP) as the plasticizer and di-(2-ethylhexyl)phosphoric acid (D2EHPA) as the extractant. With 5 M HCl aqueous solution as the strip solution, we observed an initial indium permeability of 2.4 × 10−4 m/min. However, the permeability decreases with time, dropping to about 3.4 × 10−5 m/min after 200 min of operation. Evidence was obtained showing that hydrolysis of CTA occurred, causing a dramatic decrease in the feed pH (protons transported from strip to feed solutions) and a loss of extractant and plasticizer from the membrane, and then leading to the loss of indium permeability. To alleviate the problem of hydrolysis, we proposed an operation scheme called polymer inclusion membranes with strip dispersion: dispersing the strip solution in extractant-containing oil and then bringing the dispersion to contact with the polymer membrane. Since the strong acid was dispersed in oil, the membrane did not directly contact the strong acid at all times, and membrane hydrolysis was thus alleviated and the loss of indium permeability was effectively prevented. With the proposed scheme, a stable indium permeability of 2.5 × 10−4 m/min was obtained during the whole time period of the permeation experiment. Full article
(This article belongs to the Special Issue Advanced Membranes for Water Treatment)
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Review

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Open AccessFeature PaperReview Climate–Glacier Dynamics and Topographic Forcing in the Karakoram Himalaya: Concepts, Issues and Research Directions
Water 2017, 9(6), 405; doi:10.3390/w9060405
Received: 31 March 2017 / Revised: 25 May 2017 / Accepted: 1 June 2017 / Published: 6 June 2017
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Abstract
Understanding climate-glacier dynamics in High Mountain Asia is of critical importance to address issues including water resources, sea-level rise, mountain geodynamics, natural hazards and ecosystem sustainability. The Karakoram Himalaya is arguably the least understood region, given its extreme topography, climate-system coupling, and advancing
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Understanding climate-glacier dynamics in High Mountain Asia is of critical importance to address issues including water resources, sea-level rise, mountain geodynamics, natural hazards and ecosystem sustainability. The Karakoram Himalaya is arguably the least understood region, given its extreme topography, climate-system coupling, and advancing and surge-type glaciers that exhibit complex flow patterns. Glacier fluctuations in the Karakoram Himalaya are highly variable in space and time because of numerous controlling factors, including the westerlies, the Indian summer monsoon, various teleconnections, topographic effects, glacier debris-cover characteristics, glacier dynamics, and geological conditions. The influence of the integrative coupling of forcing factors, however, has not been adequately assessed for characterizing the glaciers in the Karakoram Himalaya. Given the scarcity of in-situ data and the difficulty of conducting fieldwork on these glaciers, recent research has focused on utilizing remote sensing, geospatial technologies, and scientific modeling to obtain baseline information about the state of glaciers in the region. This review summarizes our current knowledge of glaciers, climate-glacier interaction, and topographic forcing in the Karakoram Himalaya, and demonstrates the complexities in mountain geodynamics that influence climate-glacier dynamics. Innovative analysis is also presented in support of our review and discussion. Full article
(This article belongs to the Special Issue Global Warming Impacts on Mountain Glaciers and Communities)
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Other

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Open AccessCase Report Impact of Future Climate Change on Regional Crop Water Requirement—A Case Study of Hetao Irrigation District, China
Water 2017, 9(6), 429; doi:10.3390/w9060429
Received: 11 April 2017 / Revised: 6 June 2017 / Accepted: 8 June 2017 / Published: 13 June 2017
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Abstract
Water shortage is a limiting factor for agricultural production in China, and climate change will affect agricultural water use. Studying the effects of climate change on crop irrigation requirement (CIR) would help to tackle climate change, from both food security and sustainable water
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Water shortage is a limiting factor for agricultural production in China, and climate change will affect agricultural water use. Studying the effects of climate change on crop irrigation requirement (CIR) would help to tackle climate change, from both food security and sustainable water resource use perspectives. This paper applied SDSM (Statistical DownScaling Model) to simulate future meteorological parameters in the Hetao irrigation district (HID) in the time periods 2041–2070 and 2071–2099, and used the Penman–Monteith equation to calculate reference crop evapotranspiration (ET0), which was further used to calculate crop evapotranspiration (ETc) and crop water requirement (CWR). CWR and predicted future precipitation were used to calculate CIR. The results show that the climate in the HID will become warmer and wetter; ET0 would would increase by 4% to 7%; ETc and CWR have the same trend as ET0, but different crops have different increase rates. CIR would increase because of the coefficient of the increase of CWR and the decrease of effective precipitation. Based on the current growing area, the CIR would increase by 198 × 106 to 242 × 106 m3 by the year 2041–2070, and by 342 × 106 to 456 × 106 m3 by the years 2071–2099 respectively. Future climate change will bring greater challenges to regional agricultural water use. Full article
(This article belongs to the Special Issue Adaptation Strategies to Climate Change Impacts on Water Resources)
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Open AccessErratum Erratum: Chirindja, F., et al. Borehole Logging and Slug Tests for Evaluating the Applicability of Electrical Resistivity Tomography for Groundwater Exploration in Nampula Complex, Mozambique. Water 2017, 9, 95
Water 2017, 9(6), 435; doi:10.3390/w9060435
Received: 28 April 2017 / Revised: 8 June 2017 / Accepted: 12 June 2017 / Published: 16 June 2017
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Open AccessFeature PaperAddendum Addendum: Montagnier, L.; Aïssa, J.; Capolupo, A.; Craddock, T.J.A.; Kurian, P.; Lavallee, C.; Polcari, A.; Romano, P.; Tedeschi, A.; Vitiello, G. Water Bridging Dynamics of Polymerase Chain Reaction in the Gauge Theory Paradigm of Quantum Fields. Water 2017, 9, 339
Water 2017, 9(6), 436; doi:10.3390/w9060436
Received: 16 June 2017 / Revised: 16 June 2017 / Accepted: 16 June 2017 / Published: 17 June 2017
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(This article belongs to the Special Issue Electrohydrodynamic Liquid Bridges and Electrified Water)
Open AccessShort Note A Simple Method for the Determination of Deposition Coefficient Using the Analytical Solution of Advection-Dispersion-Deposition Equation for Step Input
Water 2017, 9(6), 398; doi:10.3390/w9060398
Received: 14 March 2017 / Revised: 18 May 2017 / Accepted: 30 May 2017 / Published: 2 June 2017
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Abstract
A simple method is proposed for the determination of the deposition coefficient, which plays an important role in bacterial transport in a porous media. The method relies on the analytical solution of an advection-dispersion-deposition equation for the step input of a bacterial solution.
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A simple method is proposed for the determination of the deposition coefficient, which plays an important role in bacterial transport in a porous media. The method relies on the analytical solution of an advection-dispersion-deposition equation for the step input of a bacterial solution. The step input solution can be simplified when time goes to infinity, and thereby the deposition coefficient can be obtained as a function of the maximum concentration and peclet number. The deposition coefficient given by the simple method yields a similar expression to those of previous studies with a slight modification. Comparison of the simple method with other methods revealed that it offers an advantange of a wider application, even to a square pulse input as well as step input of a bacterial solution, and that calculation of bacterial mass fraction is not required. Theoretical validation revealed that the method can be valid for the conditions of pulse duration greater than 0.8 pore volume in the column study with Pe 300–400. Full article
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