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Water, Volume 7, Issue 9 (September 2015) , Pages 4593-5202

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Open AccessArticle
Optimal Spatial Design of Capacity and Quantity of Rainwater Harvesting Systems for Urban Flood Mitigation
Water 2015, 7(9), 5173-5202; https://doi.org/10.3390/w7095173 - 23 Sep 2015
Cited by 24 | Viewed by 2948
Abstract
This study adopts rainwater harvesting systems (RWHS) into a stormwater runoff management model (SWMM) for the spatial design of capacities and quantities of rain barrel for urban flood mitigation. A simulation-optimization model is proposed for effectively identifying the optimal design. First of all, [...] Read more.
This study adopts rainwater harvesting systems (RWHS) into a stormwater runoff management model (SWMM) for the spatial design of capacities and quantities of rain barrel for urban flood mitigation. A simulation-optimization model is proposed for effectively identifying the optimal design. First of all, we particularly classified the characteristic zonal subregions for spatial design by using fuzzy C-means clustering with the investigated data of urban roof, land use and drainage system. In the simulation method, a series of regular spatial arrangements specification are designed by using statistical quartiles analysis for rooftop area and rainfall frequency analysis; accordingly, the corresponding reduced flooding circumstances can be simulated by SWMM. Moreover, the most effective solution for the simulation method is identified from the calculated net benefit, which is equivalent to the subtraction of the facility cost from the decreased inundation loss. It serves as the initially identified solution for the optimization model. In the optimization method, backpropagation neural network (BPNN) are first applied for developing a water level simulation model of urban drainage systems to substitute for SWMM to conform to newly considered interdisciplinary multi-objective optimization model, and a tabu search-based algorithm is used with the embedded BPNN-based SWMM to optimize the planning solution. The developed method is applied to the Zhong-He District, Taiwan. Results demonstrate that the application of tabu search and the BPNN-based simulation model into the optimization model can effectively, accurately and fast search optimal design considering economic net benefit. Furthermore, the optimized spatial rain barrel design could reduce 72% of inundation losses according to the simulated flood events. Full article
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Open AccessCase Report
Flood-Runoff in Semi-Arid and Sub-Humid Regions, a Case Study: A Simulation of Jianghe Watershed in Northern China
Water 2015, 7(9), 5155-5172; https://doi.org/10.3390/w7095155 - 22 Sep 2015
Cited by 11 | Viewed by 2054
Abstract
This paper presents a modeling application of surface runoff using the Hydrologic Modelling System (HEC-HMS). A case study was carried out for the Jianghe watershed, a typical semi-arid and sub-humid geo-climatic region in northern China. Two modeling schemes using different descriptive sub-mechanism models [...] Read more.
This paper presents a modeling application of surface runoff using the Hydrologic Modelling System (HEC-HMS). A case study was carried out for the Jianghe watershed, a typical semi-arid and sub-humid geo-climatic region in northern China. Two modeling schemes using different descriptive sub-mechanism models provided by HEC-HMS for runoff volume, direct runoff and routing (channel flow) were investigated. The modeling results were compared with historical observation data. This work shows that HEC-HMS can be a suitable modeling tool for specific situations in China. With the appropriate selection of the sub-mechanism models, HEC-HMS can be applied to various situations, including the typical semi-arid and sub-humid conditions in northern China. Full article
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Open AccessCorrection
Yaya-Beas, R.-E., et al. Helminth Egg Removal Capacity of UASB Reactors under Subtropical Conditions. Water 2015, 7, 2402–2421
Water 2015, 7(9), 5152-5154; https://doi.org/10.3390/w7095152 - 22 Sep 2015
Cited by 1 | Viewed by 1704
Abstract
The authors wish to make the following corrections to their paper [1]: [...] Full article
Open AccessArticle
The Probability Density Evolution Method for Flood Frequency Analysis: A Case Study of the Nen River in China
Water 2015, 7(9), 5134-5151; https://doi.org/10.3390/w7095134 - 22 Sep 2015
Cited by 3 | Viewed by 1991
Abstract
A new approach for flood frequency analysis based on the probability density evolution method (PDEM) is proposed. It can avoid the problem of linear limitation for flood frequency analysis in a parametric method and avoid the complex process for choosing the kernel function [...] Read more.
A new approach for flood frequency analysis based on the probability density evolution method (PDEM) is proposed. It can avoid the problem of linear limitation for flood frequency analysis in a parametric method and avoid the complex process for choosing the kernel function and window width in the nonparametric method. Based on the annual maximum peak discharge (AMPD) in 54 years from the Dalai hydrologic station which is located on the downstream of Nen River in Heilongjiang Province of China, a joint probability density function (PDF) model about AMPD is built by the PDEM. Then, the numerical simulation results of the joint PDF model are given by adopting the one-sided difference scheme which has the property of direction self-adaptive. After that, according to the relationship between the marginal function and joint PDF, the PDF of AMPD can be obtained. Finally, the PDF is integrated and the frequency curve could be achieved. The results indicate that the flood frequency curve obtained by the PDEM has a better agreement with the empirical frequency than that of the parametric method widely used at present. The method based on PDEM is an effective way for hydrologic frequency analysis. Full article
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Open AccessArticle
Hydraulic Jump and Energy Dissipation with Sluice Gate
Water 2015, 7(9), 5115-5133; https://doi.org/10.3390/w7095115 - 22 Sep 2015
Cited by 4 | Viewed by 3550
Abstract
Movable weirs have been developed to address the weaknesses of conventional fixed weirs. However, the structures for riverbed protection downstream of movable weirs are designed using the criteria of fixed weirs in most cases, and these applications cause problems, such as scour and [...] Read more.
Movable weirs have been developed to address the weaknesses of conventional fixed weirs. However, the structures for riverbed protection downstream of movable weirs are designed using the criteria of fixed weirs in most cases, and these applications cause problems, such as scour and deformation of structures, due to misunderstanding the difference between different types of structures. In this study, a hydraulic experiment was conducted to examine weir type-specific hydraulic phenomena, compare hydraulic jumps and downstream flow characteristics according to different weir types, and analyze hydraulic characteristics, such as changes in water levels, velocities and energy. Additionally, to control the flow generated by a sluice gate, energy dissipators were examined herein for their effectiveness in relation to different installation locations and heights. As a result, it was found that although sluice gates generated hydraulic jumps similar to those of fixed weirs, their downstream supercritical flow increased to eventually elongate the overall hydraulic jumps. In energy dissipator installation, installation heights were found to be sensitive to energy dissipation. The most effective energy dissipator height was 10% of the downstream free surface water depth in this experiment. Based on these findings, it seems desirable to use energy dissipators to reduce energy, as such dissipators were found to be effective in reducing hydraulic jumps and protecting the riverbed under sluice gates. Full article
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Open AccessArticle
An Integrated Approach to Identify Water Resources for Human Consumption in an Area Affected by High Natural Arsenic Content
Water 2015, 7(9), 5091-5114; https://doi.org/10.3390/w7095091 - 18 Sep 2015
Cited by 8 | Viewed by 1976
Abstract
This study concerns the occurrence of arsenic in the groundwater system of the Cimino-Vico volcanic area (central Italy), different parts of which are currently widely used for local drinking water supply and for irrigation. The system shows a complex groundwater circulation, including a [...] Read more.
This study concerns the occurrence of arsenic in the groundwater system of the Cimino-Vico volcanic area (central Italy), different parts of which are currently widely used for local drinking water supply and for irrigation. The system shows a complex groundwater circulation, including a continuous basal aquifer, discontinuous perched aquifers, groundwater flows at high altitude, and local interactions with rising thermal fluids. Data on arsenic contents in 250 water samples from springs and wells and in 68 samples from rock outcrops were measured and combined with already existing information. Results highlight that arsenic concentrations of groundwater are influenced by type of aquifer, groundwater flow path, arsenic content of the aquifer rocks, and interaction with fluids rising from depth. Waters circulating in the Vico volcanics, one of the prominent rock units of the area, have high concentrations of arsenic, both for the basal and the perched aquifers. A large fraction of the waters associated with this rock unit have arsenic contents higher than 10 μg/L (82 percent for basal, 40 percent for perched). In contrast, waters circulating in the Cimino volcanics have lower arsenic contents: 30 percent of the basal and 10 percent of the perched aquifers have arsenic concentrations greater than 10 μg/L. Through an integrated approach, including leaching tests to investigate the arsenic behavior concerning the water-rock interaction and a geostatistical modeling of data, it has been possible to identify and tentatively quantify suitable water resources that have arsenic content not exceeding the quality standards for human consumption. Full article
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Open AccessArticle
Controlling River Eutrophication under Conflicts of Interests—A GIS Modeling Approach
Water 2015, 7(9), 5078-5090; https://doi.org/10.3390/w7095078 - 18 Sep 2015
Cited by 3 | Viewed by 1582
Abstract
Stream networks are highly complex systems, in which spatially complicated and temporally varying water quality patterns develop. River eutrophication is underlain by nutrient inputs across the entire stream network and is controlled by many interacting factors in an ever moving and renewing medium. [...] Read more.
Stream networks are highly complex systems, in which spatially complicated and temporally varying water quality patterns develop. River eutrophication is underlain by nutrient inputs across the entire stream network and is controlled by many interacting factors in an ever moving and renewing medium. These complex features must be perceived as a whole entity to control river eutrophication. The Szamos River is one of the largest tributaries of the Tisza River in Eastern Europe. It delivers high loads of nutrients and algal biomass and fundamentally influences the hydro-morphological, chemical and ecological status of the Tisza River. To improve the ecological status of the recipient river, nutrient and phytoplankton inputs from the tributary should be controlled, yet the two rivers belong to different countries, which are reluctant to harmonize management plans. This study aims at modeling trophic status of the tributary with the PhosFate nutrient emission model to outline a set of management measures that would satisfy both countries. Four management alternatives are analysed with altered landuse patterns, and management options. Each of these alternatives is evaluated against the present conditions. Full article
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Open AccessArticle
Combining Field and Laboratory Measurements to Determine the Erosion Risk of Cohesive Sediments Best
Water 2015, 7(9), 5061-5077; https://doi.org/10.3390/w7095061 - 18 Sep 2015
Cited by 14 | Viewed by 2323
Abstract
In contrast to non-cohesive sediments, the incipient motion of cohesive sediments is characterized by much more complex interactions between several sedimentary, biological, and chemical parameters. Thus, site-specific investigations are required to obtain information about the erosion stability of cohesive materials. This becomes even [...] Read more.
In contrast to non-cohesive sediments, the incipient motion of cohesive sediments is characterized by much more complex interactions between several sedimentary, biological, and chemical parameters. Thus, site-specific investigations are required to obtain information about the erosion stability of cohesive materials. This becomes even more relevant for contaminated sediments, stored in riverine sediments as a “burden of the past”, because of their remobilization potential during flood events. This article represents a twofold measuring strategy for the detection of erosion thresholds: an in situ device for determination of critical shear stresses in the field, and a laboratory approach where sediment cores are withdrawn and subsequently analyzed over depth. The combined measuring strategy was applied in the River Elbe and at selected sites of the catchment of the River Saale. The results show a great variety of erosion thresholds over depth, demonstrating the need to conduct vertical analyses, especially when addressing buried layers with contaminations. The latter is only possible in the laboratory but the in situ device revealed clear benefits in capturing the loose flocculent layer on top of the sediment that might be easily lost during sediment retrieval and transport. Consequently, it is ideal to combine both approaches for a comprehensive insight into sediment stability. Full article
(This article belongs to the Special Issue Recent Advances in Riverflow Research)
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Open AccessReview
Evolution of Water Lifting Devices (Pumps) over the Centuries Worldwide
Water 2015, 7(9), 5031-5060; https://doi.org/10.3390/w7095031 - 17 Sep 2015
Cited by 216 | Viewed by 10187
Abstract
The evolution of the major achievements in water lifting devices with emphasis on the major technologies over the centuries is presented and discussed. Valuable insights into ancient water lifting technologies with their apparent characteristics of durability, adaptability, and sustainability are provided. A comparison [...] Read more.
The evolution of the major achievements in water lifting devices with emphasis on the major technologies over the centuries is presented and discussed. Valuable insights into ancient water lifting technologies with their apparent characteristics of durability, adaptability, and sustainability are provided. A comparison of the relevant technological developments in several early civilizations is carried out. These technologies are the underpinning of modern achievements in water engineering. They represent the best paradigm of probing the past and facing the future. A timeline of the historical development of water pumps worldwide through the last 5500 years of the history of mankind is presented. A chronological order is followed with emphasis on the major civilizations. Full article
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Open AccessArticle
Water Quality of Four Major Lakes in Mississippi, USA: Impacts on Human and Aquatic Ecosystem Health
Water 2015, 7(9), 4999-5030; https://doi.org/10.3390/w7094999 - 15 Sep 2015
Cited by 8 | Viewed by 3126
Abstract
Harmful algal blooms (HABs), harmful microorganisms (pathogens) and toxic metals represent three major agents of water quality deterioration. Water quality of three northern lakes (Sardis, Enid, and Grenada) and a central lake (Ross Barnett Reservoir) of Mississippi, USA were examined in this study. [...] Read more.
Harmful algal blooms (HABs), harmful microorganisms (pathogens) and toxic metals represent three major agents of water quality deterioration. Water quality of three northern lakes (Sardis, Enid, and Grenada) and a central lake (Ross Barnett Reservoir) of Mississippi, USA were examined in this study. While all these lakes are heavily used for recreational purposes, the Ross Barnett Reservoir serves additionally as the primary water supply for the City of Jackson, the capital city of Mississippi. The main goal of this study was to comprehensively assess the water quality of these lakes employing field and satellite data, and evaluate the potential human and aquatic health impacts. A time-series of true color images derived from satellite data indicated that algal blooms have been a recurring phenomenon in these lakes. Cyanobacteria, the algal group that predominantly occur in freshwater and form toxic blooms, were always present in these lakes and were most abundant on many occasions. The most toxic cyanotoxin, microcystin-LR, was found in all lakes, and its concentrations exceeded federal drinking water guidelines for children under six years of age many times. Potential bioaccumulation and biomagnification of microcystin-LR may pose serious risk to the aquatic ecosystem and human health including adults. Nutrient measurements indicated that all four lakes were eutrophic. Among bacterial populations, total coliforms and enterococci exceeded guideline values on several occasions. Arsenic, cadmium, chromium, and lead were found in the water of all the lakes, with arsenic exceeding the guideline values at two sites in Ross Barnett Reservoir. While it is apparent from this study that these lakes face many water quality issues, data across all seasons will be required to document potential trends and to devise management strategies. Use of remote sensing technology is recommended to monitor some of the water quality parameters such as suspended particulate matter and algal blooms, especially cyanobacterial blooms. Full article
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Open AccessArticle
Territorial Vulnerability Assessment Supporting Risk Managing Coastal Areas Due to Tsunami Impact
Water 2015, 7(9), 4971-4998; https://doi.org/10.3390/w7094971 - 15 Sep 2015
Cited by 8 | Viewed by 1939
Abstract
Portugal’s coastline extends 1187 km. It is characterized by social, economic and physical conditions that differentiate it from the rest of the territory, including population density, location of infrastructure and support of tourism activities. Therefore, it has a significant exposure if a tsunami [...] Read more.
Portugal’s coastline extends 1187 km. It is characterized by social, economic and physical conditions that differentiate it from the rest of the territory, including population density, location of infrastructure and support of tourism activities. Therefore, it has a significant exposure if a tsunami occurs. Six coastal study sites with varying characteristics were selected for evaluation in this paper, including two core beach-use areas, two residential areas and two industrial areas. These sites are located in the municipalities of Figueira da Foz, Setúbal and Vila do Bispo. The analysis began with the calculation of the potential tsunami inundation area for each site using the 1755 Lisbon tsunami. Next, a methodology distinguished by its multidimensional character was applied to assess local vulnerability to tsunamis. This methodology assesses vulnerabilities associated with morphological, structural, social and tax factors. These four vulnerability components were combined to obtain a Composite Vulnerability Index (CVI), which enabled us to identify the most vulnerable areas and to determine the distinguishing characteristics of each area. Full article
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Open AccessArticle
Dynamic Lift on an Artificial Static Armor Layer During Highly Unsteady Open Channel Flow
Water 2015, 7(9), 4951-4970; https://doi.org/10.3390/w7094951 - 14 Sep 2015
Cited by 6 | Viewed by 2222
Abstract
The dynamic lift acting on a 100 mm × 100 mm section of a static armor layer during unsteady flow is directly measured in a series of physical experiments. The static armor layer is represented by an artificial streambed mold, made from an [...] Read more.
The dynamic lift acting on a 100 mm × 100 mm section of a static armor layer during unsteady flow is directly measured in a series of physical experiments. The static armor layer is represented by an artificial streambed mold, made from an actual gravel bed. Data from a total of 190 experiments are presented, undertaken in identical conditions. Results show that during rapid discharge increases, the dynamic lift on the streambed repeatedly exhibits three clear peaks. The magnitude of the observed lift depends on the following hydrograph characteristics: (1) the initial flow depth; (2) the ramping duration and therefore the ramping rate; and (3) the total discharge increase. An adjusted unsteadiness parameter combines those three hydrograph characteristics for rapid discharge increases. Direct correlations between the unsteadiness parameter and the measured dynamic lift during unsteady flow are presented. In addition, the armor layer porosity showed a major impact on the observed effects. It is shown that increasing bed porosity leads to decreasing dynamic lift. Full article
(This article belongs to the Special Issue Recent Advances in Riverflow Research)
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Open AccessArticle
Pollutant Dispersion Modeling in Natural Streams Using the Transmission Line Matrix Method
Water 2015, 7(9), 4932-4950; https://doi.org/10.3390/w7094932 - 09 Sep 2015
Cited by 3 | Viewed by 1620
Abstract
Numerical modeling has become an indispensable tool for solving various physical problems. In this context, we present a model of pollutant dispersion in natural streams for the far field case where dispersion is considered longitudinal and one-dimensional in the flow direction. The Transmission [...] Read more.
Numerical modeling has become an indispensable tool for solving various physical problems. In this context, we present a model of pollutant dispersion in natural streams for the far field case where dispersion is considered longitudinal and one-dimensional in the flow direction. The Transmission Line Matrix (TLM), which has earned a reputation as powerful and efficient numerical method, is used. The presented one-dimensional TLM model requires a minimum input data and provides a significant gain in computing time. To validate our model, the results are compared with observations and experimental data from the river Severn (UK). The results show a good agreement with experimental data. The model can be used to predict the spatiotemporal evolution of a pollutant in natural streams for effective and rapid decision-making in a case of emergency, such as accidental discharges in a stream with a dynamic similar to that of the river Severn (UK). Full article
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Open AccessArticle
Evapotranspiration in the Nile Basin: Identifying Dynamics and Drivers, 2002–2011
Water 2015, 7(9), 4914-4931; https://doi.org/10.3390/w7094914 - 09 Sep 2015
Cited by 5 | Viewed by 2081
Abstract
Analysis of the relationship between evapotranspiration (ET) and its natural and anthropogenic drivers is critical in water-limited basins such as the Nile. The spatiotemporal relationships of ET with rainfall and vegetation dynamics in the Nile Basin during 2002–2011 were analyzed using satellite-derived data. [...] Read more.
Analysis of the relationship between evapotranspiration (ET) and its natural and anthropogenic drivers is critical in water-limited basins such as the Nile. The spatiotemporal relationships of ET with rainfall and vegetation dynamics in the Nile Basin during 2002–2011 were analyzed using satellite-derived data. Non-parametric statistics were used to quantify ET-rainfall interactions and trends across land cover types and subbasins. We found that 65% of the study area (2.5 million km2) showed significant (p < 0.05) positive correlations between monthly ET and rainfall, whereas 7% showed significant negative correlations. As expected, positive ET-rainfall correlations were observed over natural vegetation, mixed croplands/natural vegetation, and croplands, with a few subbasin-specific exceptions. In particular, irrigated croplands, wetlands and some forests exhibited negative correlations. Trend tests revealed spatial clusters of statistically significant trends in ET (6% of study area was negative; 12% positive), vegetation greenness (24% negative; 12% positive) and rainfall (11% negative; 1% positive) during 2002–2011. The Nile Delta, Ethiopian highlands and central Uganda regions showed decline in ET while central parts of Sudan, South Sudan, southwestern Ethiopia and northeastern Uganda showed increases. Except for a decline in ET in central Uganda, the detected changes in ET (both positive and negative) were not associated with corresponding changes in rainfall. Detected declines in ET in the Nile delta and Ethiopian highlands were found to be attributable to anthropogenic land degradation, while the ET decline in central Uganda is likely caused by rainfall reduction. Full article
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Open AccessArticle
Secondary Currents and Turbulence over a Non-Uniformly Roughened Open-Channel Bed
Water 2015, 7(9), 4896-4913; https://doi.org/10.3390/w7094896 - 09 Sep 2015
Cited by 16 | Viewed by 2276
Abstract
Large-eddy simulations (LES) of the flow over a non-uniformly roughened channel bed are carried out to study the effect of non-uniform bed roughness on turbulence driven secondary currents and turbulence statistics. The channel bed is comprised of alternating rough and smooth strips, the [...] Read more.
Large-eddy simulations (LES) of the flow over a non-uniformly roughened channel bed are carried out to study the effect of non-uniform bed roughness on turbulence driven secondary currents and turbulence statistics. The channel bed is comprised of alternating rough and smooth strips, the width of which corresponds to the water depth. The Reynolds number based on hydraulic radius and bulk velocity is 34,000. The LES are successfully validated using experimental data. The secondary flow and bed roughness have a significant effect on the streamwise velocity and second order turbulence statistics. Turbulence is enhanced over rough strips and suppressed over smooth strips. Significant lateral momentum transfer takes place due to both advection and turbulence. The bed shear stresses over the smooth strips are approximately four times less than over the rough strips a result of near bed low momentum fluid being transported from the rough strips to the smooth strips and high momentum fluid being convected from the surface towards the bed. The most significant terms in the streamwise momentum equation are quantified and discussed with regard to momentum transfer. Full article
(This article belongs to the Special Issue Recent Advances in Riverflow Research)
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Open AccessEditorial
Wastewater Treatment and Reuse: Past, Present, and Future
Water 2015, 7(9), 4887-4895; https://doi.org/10.3390/w7094887 - 09 Sep 2015
Cited by 34 | Viewed by 4166
Abstract
This paper provides an overview of the Special Issue on Wastewater Treatment and Reuse: Past, Present, and Future. The papers selected for publication include advanced wastewater treatment and monitoring technologies, such as membrane bioreactors, electrochemical systems; denitrifying biofilters, and disinfection technologies. The Issue [...] Read more.
This paper provides an overview of the Special Issue on Wastewater Treatment and Reuse: Past, Present, and Future. The papers selected for publication include advanced wastewater treatment and monitoring technologies, such as membrane bioreactors, electrochemical systems; denitrifying biofilters, and disinfection technologies. The Issue also contains articles related to best management practices of biosolids, the influence of organic matter on pathogen inactivation and nutrient removal. Collectively, the Special Issue presents an evolution of technologies, from conventional through advanced, for reliable and sustainable wastewater treatment and reuse. Full article
(This article belongs to the Special Issue Wastewater Treatment and Reuse)
Open AccessArticle
Impact Analysis of Lakefront Land Use Changes on Lake Area in Wuhan, China
Water 2015, 7(9), 4869-4886; https://doi.org/10.3390/w7094869 - 08 Sep 2015
Cited by 11 | Viewed by 2147
Abstract
Wuhan, the central city in the middle reach of the Yangtze River of China, is famous for its lake resources. However, the city’s lake area decreased by 37.4% from 1991 to 2005. This study aims to analyze the relationships between lake area reduction [...] Read more.
Wuhan, the central city in the middle reach of the Yangtze River of China, is famous for its lake resources. However, the city’s lake area decreased by 37.4% from 1991 to 2005. This study aims to analyze the relationships between lake area reduction and lakefront land use changes in Wuhan. In this paper, the connections between the spatial changes of lake areal extent and land use changes in the lakefront were established with mathematical models such as Moran’s I and spatial analysis models such as transition matrix. Regarding the impacts of lakefront land use changes on lake area in the urban and suburban districts of Wuhan City, it can be concluded that: (1) the loss rate of lake area would be increased if the proportions of lakefront land use changes transformed into developed or agricultural land from other land use categories became higher; (2) the higher spatial autocorrelation of lakefront land use classifications (Moran’s I > 0.25) could be an indicator for the loss rate of lake area in urban district of the city; and (3) the vector sum of lakefront land use changes was related to the displacement of lake center. Full article
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Open AccessTechnical Note
A Web-Based Tool to Estimate Pollutant Loading Using LOADEST
Water 2015, 7(9), 4858-4868; https://doi.org/10.3390/w7094858 - 08 Sep 2015
Cited by 9 | Viewed by 2290
Abstract
Collecting and analyzing water quality samples is costly and typically requires significant effort compared to streamflow data, thus water quality data are typically collected at a low frequency. Regression models, identifying a relationship between streamflow and water quality data, are often used to [...] Read more.
Collecting and analyzing water quality samples is costly and typically requires significant effort compared to streamflow data, thus water quality data are typically collected at a low frequency. Regression models, identifying a relationship between streamflow and water quality data, are often used to estimate pollutant loads. A web-based tool using LOAD ESTimator (LOADEST) as a core engine with four modules was developed to provide user-friendly interfaces and input data collection via web access. The first module requests and receives streamflow and water quality data from the U.S. Geological Survey. The second module retrieves watershed area for computation of pollutant loads per unit area. The third module examines potential error of input datasets for LOADEST runs, and the last module computes estimated and allowable annual average pollutant loads and provides tabular and graphical LOADEST outputs. The web-based tool was applied to two watersheds in this study, one agriculturally-dominated and one urban-dominated. It was found that annual sediment load at the urban-dominant watershed exceeded the target load; therefore, the web-based tool identified correctly the watershed requiring best management practices to reduce pollutant loads. Full article
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Open AccessArticle
Reclaimed Water Use in Biofuel Production
Water 2015, 7(9), 4848-4857; https://doi.org/10.3390/w7094848 - 04 Sep 2015
Cited by 1 | Viewed by 2152
Abstract
Jatropha curcas L., a toxic species that does not interfere with the food chain, produces biodiesel of better environmental quality than mineral oils. However, in order to cultivate it sustainably, it is necessary to optimize the limited resources used, mainly water and soil. [...] Read more.
Jatropha curcas L., a toxic species that does not interfere with the food chain, produces biodiesel of better environmental quality than mineral oils. However, in order to cultivate it sustainably, it is necessary to optimize the limited resources used, mainly water and soil. Therefore, in arid areas, it is necessary to cultivate under intensive conditions, irrigate with reclaimed water and cut production costs. To optimize water consumption, partial root-zone drying (PRD), which keeps a part of the root system dry, was used. This water management strategy, employed successfully in other oil crops, yielded less fruit per bunch, but more fruit bunches per plant. This fact will probably allow to establish higher planting density and, consequently, higher productivity per surface unit. This is one of the few available options for improving profitability as production per tree is stable (1.25 kg seed plant−1 year−1 for the most productive trees, with excellent climate and soil, and no limitations water use). A high percentage of fruit lying on the ground (24%) and non-uniform timing in fruit production (except some specimens) greatly hinder its mechanization. Although this crop’s environmental and socio-economic benefits are not taken into account, it is very difficult, with only the calculated water consumption (15.5 m3 water per L of oil or 5.6 m3 water per L of oil according to our best estimations), to consider it a profitable option. Full article
(This article belongs to the Special Issue Study, Development and Management of Water in Volcanic Areas)
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Open AccessArticle
Genetic Algorithm-Based Fuzzy Comprehensive Evaluation of Water Quality in Dongzhaigang
Water 2015, 7(9), 4821-4847; https://doi.org/10.3390/w7094821 - 02 Sep 2015
Cited by 9 | Viewed by 1975
Abstract
The concentrations of dissolved inorganic nitrogen (DIN; NO2–N, NH3–N, and NO3–N), PO43−–P, dissolved oxygen (DO), chemical oxygen demand (COD), five-day biological oxygen demand (BOD5), oil, Si, and seven heavy metals [...] Read more.
The concentrations of dissolved inorganic nitrogen (DIN; NO2–N, NH3–N, and NO3–N), PO43−–P, dissolved oxygen (DO), chemical oxygen demand (COD), five-day biological oxygen demand (BOD5), oil, Si, and seven heavy metals (Hg, Cr, Cu, As, Zn, Pb, and Cd) in seawater from the Dongzhaigang National Mangrove Nature Reserve of China in 2013 were determined. Except for the concentrations of the COD, BOD5, Cr, Hg, Cu, As, and Cd, each index in seawater were found to be over the limits of I-Class seawater standards. The index of organic pollution showed that the pollution level in this study area reached level 6; eutrophication levels indicated that the nutritional level reached level 4. According to the water quality index model, the sea area was slightly polluted by heavy metals. In a genetic algorithm-based fuzzy comprehensive evaluation, the results for organic pollutants, nutrients, and heavy metal pollution can be combined to evaluate the water quality as a whole. Results showed that the sea area in Dongzhaigang did not have a healthy water environment, but was seriously polluted by organic pollutants and nutrients. Full article
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Open AccessArticle
Applying a Correlation Analysis Method to Long-Term Forecasting of Power Production at Small Hydropower Plants
Water 2015, 7(9), 4806-4820; https://doi.org/10.3390/w7094806 - 02 Sep 2015
Cited by 5 | Viewed by 2064
Abstract
Forecasting long-term power production of small hydropower (SHP) plants is of great significance for coordinating with large-medium hydropower (LHP) plants. Accurate forecasting can solve the problems of waste-water and abandoned electricity and ensure the safe operation of the power system. However, it faces [...] Read more.
Forecasting long-term power production of small hydropower (SHP) plants is of great significance for coordinating with large-medium hydropower (LHP) plants. Accurate forecasting can solve the problems of waste-water and abandoned electricity and ensure the safe operation of the power system. However, it faces a series of challenges, such as lack of sufficient data, uncertainty of power generation, no regularity of a single station and poor forecasting models. It is difficult to establish a forecasting model based on classical and mature prediction models. Therefore, this paper introduces a correlation analysis method for forecasting power production of SHP plants. By analyzing the correlation between SHP and LHP plants, a safe conclusion can be drawn that the power production of SHP plants show similar interval inflow to LHP plants in the same region. So a regression model is developed to forecast power production of SHP plants by using the forecasting inflow values of LHP plants. Taking the SHP plants in Yunnan province as an example, the correlation between SHP and LHP plants in a district or county are analyzed respectively. The results show that this correlation method is feasible. The proposed forecasting method has been successfully applied to forecast long-term power production of SHP plants in the 13 districts of the Yunnan Power Grid. From the results, the rationality, accuracy and generality of this method have been verified. Full article
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Open AccessArticle
Sharing Benefits in Transboundary Rivers: An Experimental Case Study of Central Asian Water-Energy-Agriculture Nexus
Water 2015, 7(9), 4778-4805; https://doi.org/10.3390/w7094778 - 02 Sep 2015
Cited by 19 | Viewed by 2704
Abstract
Cooperation in transboundary river basins is challenged by the riparian countries’ differing needs for water use. This is the case especially in Amu Darya Basin in Central Asia, where upstream Tajikistan is building the Rogun Hydropower Plant (RHP) to increase its energy security, [...] Read more.
Cooperation in transboundary river basins is challenged by the riparian countries’ differing needs for water use. This is the case especially in Amu Darya Basin in Central Asia, where upstream Tajikistan is building the Rogun Hydropower Plant (RHP) to increase its energy security, while the downstream countries oppose the plant due to the feared negative impacts to their irrigated agriculture. Several experimental scenarios illustrate how the concept of benefit sharing could be used as a framework to investigate these water-energy-agriculture linkages in a transboundary context. Using a hydro-economic model, we investigate the economic benefits of various scenarios emphasizing agricultural and/or energy production, thus benefiting the riparian countries uniquely. Subsequently, we discuss how benefit-sharing arrangements with different forms of compensations could be used as a mechanism to facilitate transboundary cooperation. Our results indicate that several scenarios have a potential to increase the total energy-agriculture benefits in the basin. Yet, agreeing on the actual benefit-sharing mechanism between the countries poses special challenges as each may require countries to give up some of their anticipated maximum potential benefits. The presented scenarios provide a potential starting point for debates over benefit-sharing arrangements across countries needing to address the water-energy-agriculture nexus. Full article
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Open AccessArticle
Integrated River and Coastal Flow, Sediment and Escherichia coli Modelling for Bathing Water Quality
Water 2015, 7(9), 4752-4777; https://doi.org/10.3390/w7094752 - 01 Sep 2015
Cited by 7 | Viewed by 2154
Abstract
Due to the increasing economic and cultural value of bathing waters and the shellfish industry in the UK and worldwide, water quality in estuarine and coastal waters has attracted considerable public attention in recent years. To obtain accurate predictions of the concentration distributions [...] Read more.
Due to the increasing economic and cultural value of bathing waters and the shellfish industry in the UK and worldwide, water quality in estuarine and coastal waters has attracted considerable public attention in recent years. To obtain accurate predictions of the concentration distributions of faecal indicator organisms (FIOs) in coastal waters for better management of bathing water compliance, it is necessary to build an integrated modelling system to predict the complete diffuse and point source inputs from river and catchment basins. In the present paper, details are given of the development of such an integrated modelling system for simulating the transport and decay processes of FIOs, from catchment areas upstream from the coastal region, in which a distributed catchment module, a 1D river network module and a 2D estuarine and coastal module are linked dynamically by boundary inputs and outputs. Extensive measured data from the catchments, river networks and estuaries have been collated to determine the model parameters. Verification results of the distribution of water levels, flows and velocities, and suspended sediment and Escherichia coli concentrations, at controlled monitoring sites are presented, which show that the integrated model predictions generally agree well with the measurements, although locally appreciable errors can occur. The model results also highlight the importance of including the flux of FIOs via sediments being an important factor in terms of assessing the quality of bathing waters. The main factors influencing the relatively high concentration values in the bathing region are analysed, based on the model predictions and measured data, with four categories of FIO concentration levels being reviewed. Full article
(This article belongs to the Special Issue Recent Advances in Riverflow Research)
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Open AccessArticle
Flow Patterns in an Open Channel Confluence with Increasingly Dominant Tributary Inflow
Water 2015, 7(9), 4724-4751; https://doi.org/10.3390/w7094724 - 31 Aug 2015
Cited by 25 | Viewed by 2406
Abstract
Despite the ratio of incoming discharges being recognized as a key parameter in open-channel confluence hydrodynamics, little is known about the flow patterns when the tributary provides more than 90% of the total discharge. This paper offers a systematic study of flow features [...] Read more.
Despite the ratio of incoming discharges being recognized as a key parameter in open-channel confluence hydrodynamics, little is known about the flow patterns when the tributary provides more than 90% of the total discharge. This paper offers a systematic study of flow features when the tributary becomes increasingly dominant in a 90° confluence with a fixed concordant bed. Large-eddy simulations are used to investigate the three-dimensional complex flow patterns for three different discharge ratios. It is found that the tributary flow impinges on the opposing bank when the tributary flow becomes sufficiently dominant, causing a recirculating eddy in the upstream channel of the confluence, which induces significant changes in the incoming velocity distribution. Moreover, it results in stronger helicoidal cells in the downstream channel, along with zones of upwelling flow. In turn, the changed flow patterns also influence the mixing layer and the flow recovery. Finally, intermittent events of stronger upwelling flow are discerned. Improved understanding of flow patterns at confluences where the tributary is dominant is applicable to both engineering and earth sciences. Full article
(This article belongs to the Special Issue Recent Advances in Riverflow Research)
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Open AccessArticle
Pressure-Discharge Law of Local Tanks Connected to a Water Distribution Network: Experimental and Mathematical Results
Water 2015, 7(9), 4701-4723; https://doi.org/10.3390/w7094701 - 28 Aug 2015
Cited by 6 | Viewed by 1968
Abstract
In many Mediterranean countries, users store water resources in private tanks, which are typically located on rooftops. These local reservoirs are generally connected directly to the water distribution network (WDN). This installation scheme causes a disconnection of the WDN from the users, and [...] Read more.
In many Mediterranean countries, users store water resources in private tanks, which are typically located on rooftops. These local reservoirs are generally connected directly to the water distribution network (WDN). This installation scheme causes a disconnection of the WDN from the users, and thus, the users’ water supply is no longer linked to their consumption, which changes the network operating conditions from the designed conditions. For WDNs characterized by the presence of several private tanks, specific models have to be developed to correctly simulate the operation of the WDN while accounting for reservoirs located between the hydraulic network and users. Some mathematical models that are able to reproduce the tank emptying/filling cycles have already been developed, which combine a tank continuity equation with a float valve emitter law. In the present work, a new emitter law is proposed that improves the predictability of actual models. The new formulation takes into account the variation of the emitter coefficient and of the discharge area during the phases of the filling process of private tanks. Specifically, hyperbolic tangent laws were adopted. A comparison between the proposed mathematical model and the experimental data demonstrated the ability of the new law to estimate the flow discharging into private tanks independently of the float valve branch and of the pressure in the network. The developed model can easily be implemented in hydrodynamic models to take private tanks into account. Full article
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Open AccessArticle
Combined ICESat and CryoSat-2 Altimetry for Accessing Water Level Dynamics of Tibetan Lakes over 2003–2014
Water 2015, 7(9), 4685-4700; https://doi.org/10.3390/w7094685 - 27 Aug 2015
Cited by 20 | Viewed by 2053
Abstract
Long-term observations of lake water level are essential to our understanding of the evolution of Tibetan lake system. CryoSat-2 radar altimetry data over the Tibetan Plateau (2010–2014, P2) is used to extend lake level measurements from ICESat laser altimetry (2003–2009, P [...] Read more.
Long-term observations of lake water level are essential to our understanding of the evolution of Tibetan lake system. CryoSat-2 radar altimetry data over the Tibetan Plateau (2010–2014, P2) is used to extend lake level measurements from ICESat laser altimetry (2003–2009, P1). This study evaluates the performance of CryoSat-2 data by comparing with gauge-based water levels that are calibrated by ICESat-observed water level time series, and quantifies the uncertainty of water-level change rate estimates from satellite altimetry measurements. We completely investigate the 131 lakes that were observed by both ICESat and CryoSat-2. The mean change rate of water level for all of examined lakes in P2 (0.19 ± 0.03 m·year–1) is slightly lower than that (0.21 ± 0.02 m·year–1) observed in P1. The extended lake level time series also indicates that, in the past few years, lakes in the Northern Changtang (especially in Hol Xil) showed accelerated growth; and that the extensive lake level rises north to the Gangdise Mountains, during 2003–2009, were found dampened during the CryoSat-2 observation period. The spatio-temporal heterogeneity of precipitation observed from weather stations can be used to partly explain the observed temporal pattern of lake level changes over different sub-zones of the plateau. Full article
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Open AccessArticle
Water Security in the Syr Darya Basin
Water 2015, 7(9), 4657-4684; https://doi.org/10.3390/w7094657 - 27 Aug 2015
Cited by 17 | Viewed by 3417
Abstract
The importance of water security has gained prominence on the international water agenda, but the focus seems to be directed towards water demand. An essential element of water security is the functioning of public organizations responsible for water supply through direct and indirect [...] Read more.
The importance of water security has gained prominence on the international water agenda, but the focus seems to be directed towards water demand. An essential element of water security is the functioning of public organizations responsible for water supply through direct and indirect security approaches. Despite this, there has been a tendency to overlook the water security strategies of these organizations as well as constraints on their operation. This paper discusses the critical role of water supply in achieving sustainable water security and presents two case studies from Central Asia on the management of water supply for irrigated agriculture. The analysis concludes that existing water supply bureaucracies need to be revitalized to effectively address key challenges in water security. Full article
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Open AccessArticle
A Multi-Scale Approach in Hydraulic Characterization of a Metamorphic Aquifer: What Can Be Inferred about the Groundwater Abstraction Possibilities
Water 2015, 7(9), 4638-4656; https://doi.org/10.3390/w7094638 - 27 Aug 2015
Cited by 6 | Viewed by 1669
Abstract
Hard-rock aquifers, which constitute a water supply source in many countries, are highly heterogeneous and defining a realistic model of an aquifer can be extremely complex. The objective of this study was to hydraulically characterize a metamorphic aquifer in a representative area of [...] Read more.
Hard-rock aquifers, which constitute a water supply source in many countries, are highly heterogeneous and defining a realistic model of an aquifer can be extremely complex. The objective of this study was to hydraulically characterize a metamorphic aquifer in a representative area of Italy and to identify the most appropriate approach for tapping of groundwater in this challenging environment. The results of surface fracture surveys, injection tests, pumping tests, and a simplified numerical model were compared. From the surface fracture survey, a model of the rock mass characterized by a well-developed discontinuity network and by a high frequency of discontinuities resulted. The injection tests showed the extreme heterogeneity and the lower hydraulic conductivity of the rock mass in comparison with the results of the pumping tests. The independent estimate of the hydraulic parameter resulting from numerical model highlighted a range of values higher than those resulting from the pumping tests. The study demonstrated that the continuum medium approach can be used in the case of hard-rock aquifers with a dense network of discontinuities. The multi-scale approach is recommended for investigating hydraulic heterogeneity and significantly helps to identify the most promising areas for well locations and their characteristics in relation to the style of fracturing. Full article
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Open AccessArticle
Estimating the Rainwater Potential per Household in an Urban Area: Case Study in Central Mexico
Water 2015, 7(9), 4622-4637; https://doi.org/10.3390/w7094622 - 27 Aug 2015
Cited by 7 | Viewed by 1963
Abstract
In cities with problems of aridity and a shortage of drinking water supply, there is an urgent need to establish alternatives for an adequate water management program. This study proposes an estimation through which users can select a rainwater harvesting system for non-drinking [...] Read more.
In cities with problems of aridity and a shortage of drinking water supply, there is an urgent need to establish alternatives for an adequate water management program. This study proposes an estimation through which users can select a rainwater harvesting system for non-drinking water consumption. For the cities of Pachuca and Mineral de la Reforma, State of Hidalgo, Central Mexico, the historical record of rainfall analyzed covers a period of 33 years (1980–2013). We calculated the monthly volume of rainwater harvestable from roof areas (VR, m3) with household roof areas (Hra) of 45 m2, 50 m2, 100 m2 and 200 m2. It is proposed to replace in each single house the flush toilets and washing machine with ecological devices with consumptions of 4.8 L/flush and 70 L/load, respectively. Furthermore, a maximum and a minimum consumption of eight and six flushes/day/person (flush toilets) and five and four loads/week (washing machine), respectively, are proposed. From these considerations, our estimations of the harvestable rainwater showed that households with Hra of 45 m2 and 50 m2 would depend on the water supply system of the public network during part of the year. On the other hand, households with Hra of 100 m2 and 200 m2 might be able to store enough water to meet other needs besides toilet flushing and laundry. Full article
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Open AccessArticle
Improved Drinking Water Disinfection with UVC-LEDs for Escherichia Coli and Bacillus Subtilis Utilizing Quartz Tubes as Light Guide
Water 2015, 7(9), 4605-4621; https://doi.org/10.3390/w7094605 - 25 Aug 2015
Cited by 12 | Viewed by 2729
Abstract
A new approach is investigated utilizing light guidance capabilities of optical pure quartz glass in order to maximize drinking water disinfection efficiency with UVC-light-emitting diodes (LEDs). Two experimental setups consisting of soda-lime AR® glass (VWR, Darmstadt, Germany) or HSQ® 100 quartz [...] Read more.
A new approach is investigated utilizing light guidance capabilities of optical pure quartz glass in order to maximize drinking water disinfection efficiency with UVC-light-emitting diodes (LEDs). Two experimental setups consisting of soda-lime AR® glass (VWR, Darmstadt, Germany) or HSQ® 100 quartz glass (Heraeus, Wasserburg, Germany) reactors were designed to compare disinfection rates with and without total reflection of UVC radiation along the reactor walls. Each reactor was filled with 9 mL bacteria samples containing either E. coli DSM (Deutsche Sammlung von Mikroorganismen) 498 or B. subtilis DSM 402 strains (concentration 1–3 × 106 colony forming units (CFU)/mL) with and without additional mixing and irradiation periods of 10, 40, and 90 s. Disinfection rates were increased up to 0.95 log10 (E. coli) and 0.75 log10 (B. subtilis) by the light guide approach in stagnant samples. The same experiments with mixing of the samples resulted in an increased disinfection efficiency of 3.07 log10 (E. coli) and 1.59 log10 (B. subtilis). Optical calculations determine that total reflection is achieved with the applied UVC-LED’s viewing angle of 15°. Furthermore measurements show that HSQ® 100 quartz has a transmittance of 92% at 280 nm UVC irradiation compared to the transmittance of soda-lime glass of 2% (1 mm wall thickness). Full article
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