Next Issue
Previous Issue

E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Table of Contents

Water, Volume 9, Issue 9 (September 2017)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Cover Story Groundwater resources of low-lying atoll islands are threatened due to changes in rainfall, wave [...] Read more.
View options order results:
result details:
Displaying articles 1-97
Export citation of selected articles as:

Research

Jump to: Review, Other

Open AccessArticle Sponge City Construction in China: A Survey of the Challenges and Opportunities
Water 2017, 9(9), 594; doi:10.3390/w9090594
Received: 15 June 2017 / Revised: 3 August 2017 / Accepted: 7 August 2017 / Published: 28 August 2017
Cited by 2 | PDF Full-text (3112 KB) | HTML Full-text | XML Full-text
Abstract
Rapid urbanization in China has caused severe water and environmental problems in recent years. To resolve the issues, the Chinese government launched a sponge city construction program in 2015. While the sponge city construction initiative is drawing attention and is spreading fast nationwide,
[...] Read more.
Rapid urbanization in China has caused severe water and environmental problems in recent years. To resolve the issues, the Chinese government launched a sponge city construction program in 2015. While the sponge city construction initiative is drawing attention and is spreading fast nationwide, some challenges and risks remain. This study surveyed progress of all 30 pilot sponge cities and identified a broad array of challenges from technical, physical, regulatory, and financial, to community and institutional. The most dominant challenges involve uncertainties and risks. To resolve the issues, this study also identified various opportunities to improve China’s sponge city construction program. Based on the results, recommendations are proposed including urging local governments to adopt sponge city regulations and permits to alleviate water quality and urban pluvial flooding issues, fully measuring and accounting for economic and environmental benefits, embracing regional flexibility and results-oriented approaches, and focusing on a wider range of funding resources to finance the sponge city program. Coordination among other government agencies is critical, and this is true at all level of governments. Only through greater coordination, education, and broader funding could the sponge city program be advanced meaningfully and sustainably. Full article
(This article belongs to the Special Issue Urban Water Cycle Modelling and Management)
Figures

Figure 1

Open AccessArticle Reconstruction of an Acid Water Spill in a Mountain Reservoir
Water 2017, 9(9), 613; doi:10.3390/w9090613
Received: 23 June 2017 / Revised: 28 July 2017 / Accepted: 2 August 2017 / Published: 1 September 2017
PDF Full-text (5307 KB) | HTML Full-text | XML Full-text
Abstract
The Olivargas Reservoir is located in a remote and scarcely monitored area in the Odiel River Basin (Southwest Spain) and is used for domestic, agricultural and mining water supplies. In contrast with highly monitored reservoirs, this paper explores the application of the CE-QUAL-W2
[...] Read more.
The Olivargas Reservoir is located in a remote and scarcely monitored area in the Odiel River Basin (Southwest Spain) and is used for domestic, agricultural and mining water supplies. In contrast with highly monitored reservoirs, this paper explores the application of the CE-QUAL-W2 model, that was designed by Cole and Wells in 2005, to a poorly monitored reservoir and the utility of the results obtained. The model satisfactorily reproduced the water head measured continuously over three years, temperature (T), total dissolved solids (TDS), dissolved oxygen (DO) and pH measured bimonthly in a depth profile near the dam. A significant increase in TDS and decrease in DO and pH profiles were observed for four months, especially in the hypolimnion. The model reproduced changes in the parameters by assuming the occurrence of an acid water spill into the reservoir. A comparison of calculated results and measured TDS and DO prompted the conclusion that the spill consisted of approximately 3000 t of TDS (mainly sulfates) and 26 t of Fe(II) flowing into the reservoir for approximately 15 days at rates of approximately two and 0.02 kg/s, respectively. Full article
(This article belongs to the Special Issue Water Quality Monitoring and Modeling in Lakes)
Figures

Figure 1

Open AccessArticle A Comparative Study of GRACE with Continental Evapotranspiration Estimates in Australian Semi-Arid and Arid Basins: Sensitivity to Climate Variability and Extremes
Water 2017, 9(9), 614; doi:10.3390/w9090614
Received: 27 January 2017 / Revised: 2 May 2017 / Accepted: 30 July 2017 / Published: 5 September 2017
Cited by 2 | PDF Full-text (7236 KB) | HTML Full-text | XML Full-text
Abstract
This study examines the dynamics and robustness of large-scale evapotranspiration products in water-limited environments. Four types of ET products are tested against rainfall in two large semi-arid to arid Australian basins from 2003 to 2010: two energy balance ET methods which are forced
[...] Read more.
This study examines the dynamics and robustness of large-scale evapotranspiration products in water-limited environments. Four types of ET products are tested against rainfall in two large semi-arid to arid Australian basins from 2003 to 2010: two energy balance ET methods which are forced by optical satellite retrievals from MODIS; a newly developed land surface model (AWRA); and one approach based on observations from the Gravity Recovery and Climate Experiment (GRACE) and rainfall data. The two basins are quasi (Murray-Darling Basin: 1.06 million km2) and completely (Lake Eyre Basin: 1.14 million km2) endorheic. During the study period, two extreme climatic events—the Millennium drought and the strongest La Niña event—were recorded in the basins and are used in our assessment. The two remotely-sensed ET products constrained by the energy balance tended to overestimate ET flux over water-stressed regions. They had low sensitivity to climatic extremes and poor capability to close the water balance. However, these two remotely-sensed and energy balance products demonstrated their superiority in capturing spatial features including over small-scale and complicated landscapes. AWRA and GRACE formulated in the water balance framework were more sensitive to rainfall variability and yielded more realistic ET estimates during climate extremes. GRACE demonstrated its ability to account for seasonal and inter-annual change in water storage for ET evaluation. Full article
(This article belongs to the Special Issue The Use of Remote Sensing in Hydrology)
Figures

Figure 1

Open AccessFeature PaperArticle Photodynamic Action against Wastewater Microorganisms and Chemical Pollutants: An Effective Approach with Low Environmental Impact
Water 2017, 9(9), 630; doi:10.3390/w9090630
Received: 21 June 2017 / Revised: 12 August 2017 / Accepted: 12 August 2017 / Published: 23 August 2017
PDF Full-text (3245 KB) | HTML Full-text | XML Full-text
Abstract
Wastewater (WW) from urban and industrial activities is often contaminated with microorganisms and chemical pollutants. To reduce the concentration of microorganisms in WW to levels comparable to those found in natural waters, the sewage effluent is usually subjected to disinfection with chlorine, ozone,
[...] Read more.
Wastewater (WW) from urban and industrial activities is often contaminated with microorganisms and chemical pollutants. To reduce the concentration of microorganisms in WW to levels comparable to those found in natural waters, the sewage effluent is usually subjected to disinfection with chlorine, ozone, or ultraviolet light, which may lead to the formation of toxic products and contribute to the selection of resistant genes. Moreover, the changing patterns of infectious diseases and the emerging of multidrug resistant microbial strains entail the development of new technologies for WW decontamination. Microbial photodynamic inactivation (PDI) with photosensitizers, oxygen, and visible light has demonstrated to be effective in the inactivation of microorganisms via photogeneration of reactive oxygen species able to induce microbial damage at the external structures level. The promising results of PDI suggest that this principle can be applied to WW treatment to inactivate microorganisms but also to photodegrade chemical pollutants. The aim of this study was to assess the applicability of PDI for the microbial and chemical decontamination of secondarily treated WW. To evaluate the efficiency of bacterial inactivation in WW, experiments were done in both phosphate buffer saline (PBS) and filtered WW with the bioluminescent Escherichia coli, using small and large volumes of WW. The potential of PDI to inactivate the native bacteria (E. coli and Enterococcus) present in WW was tested and assays without the adding of bacteria to the WW were performed. It was also tested if the same PDI protocol was able to induce phototransformation of phenol. The cationic porphyrin 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetra-iodide (Tetra-Py+-Me) was shown to be effective against both bacterial groups representing both Gram-negative and Gram-positive bacteria used as microbiological parameters to instigate water quality and even showing the power to photooxidate organic compounds. As the photosensitizer when immobilized on solid matrixes can be easily removed, recovered, and reused, an effective, less-expensive, easy-applicable, and environmentally friendly technology can be applied to treat WW, inactivating microorganisms and degrading chemical contaminants at the same time. Full article
(This article belongs to the Special Issue New Advances in Disinfection of Wastewater)
Figures

Figure 1

Open AccessArticle Delineation of Salt Water Intrusion through Use of Electromagnetic-Induction Logging: A Case Study in Southern Manhattan Island, New York
Water 2017, 9(9), 631; doi:10.3390/w9090631
Received: 12 May 2017 / Revised: 17 August 2017 / Accepted: 19 August 2017 / Published: 23 August 2017
PDF Full-text (8894 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Groundwater with chloride concentrations up to 15,000 mg/L has intruded the freshwater aquifer underlying southern Manhattan Island, New York. Historical (1940–1950) chloride concentration data of glacial aquifer wells in the study area indicate the presence of four wedges of saltwater intrusion that may
[...] Read more.
Groundwater with chloride concentrations up to 15,000 mg/L has intruded the freshwater aquifer underlying southern Manhattan Island, New York. Historical (1940–1950) chloride concentration data of glacial aquifer wells in the study area indicate the presence of four wedges of saltwater intrusion that may have been caused by industrial pumpage. The limited recharge capability of the aquifer, due to impervious surfaces and the 22.7 million liters per day (mld) of reported industrial pumpage early in the 20th Century was probably the cause for the saltwater intrusion and the persistence of the historical saltwater intrusion wedges over time. Recent drilling of wells provided new information on the hydrogeology and extent of saltwater intrusion of the glacial aquifer overlying bedrock. The new observation wells provided ground-water level, chloride concentration, hydraulic conductivity, and borehole geophysical data of the glacial aquifer. The glacial sediments range in thickness from less than 0.3 m to more than 76.2 m within the study area. A linear relation between Electromagnetic-induction (EM) conductivity log response and measured chloride concentration was determined. Using this relation, chloride concentration was estimated in parts of the glacial aquifer where sampling was not possible. EM logging is an effective tool to monitor changes in saltwater intrusion wedges. Full article
Figures

Figure 1

Open AccessArticle An Entropy-Based Investigation into Bivariate Drought Analysis in China
Water 2017, 9(9), 632; doi:10.3390/w9090632
Received: 17 June 2017 / Revised: 17 August 2017 / Accepted: 20 August 2017 / Published: 23 August 2017
PDF Full-text (17369 KB) | HTML Full-text | XML Full-text
Abstract
Because of the high correlation between random variables of drought duration and severity, their joint distribution is difficult to obtain by traditional mathematical methods. However, the copula method has proved to be a useful tool for analyzing the frequency of drought duration and
[...] Read more.
Because of the high correlation between random variables of drought duration and severity, their joint distribution is difficult to obtain by traditional mathematical methods. However, the copula method has proved to be a useful tool for analyzing the frequency of drought duration and severity. Most studies have used different marginal distribution functions to fit the drought duration and severity distributions. This requires a great deal of contrast analysis, and sometimes two or more distributions fit the data well. Based on entropy theory, however, a unified probability distribution function is derived which reduces complex contrast analysis and improves the filtering distribution function. Based on monthly precipitation data at 162 stations in China for 1961–2015, the monthly standardized precipitation index was calculated and used to extract drought duration and severity. Then the entropy distribution was used to fit the distributions of drought duration and severity, and to establish the correspondence between them. The probabilities of the interval and return periods were then determined using the copula method. An analysis of the discrepancy between the conventional and entropy-based methods indicated that the entropy distribution showed a better fit than conventional methods for drought duration distribution, although no obvious difference was found in drought severity distribution. The entropy-based results were more consistent with the empirical data, whereas conventional methods showed apparent deviation in some drought types. Hence, the entropy-based method is proposed as an alternative method of deriving the marginal distributions of drought duration and severity, and for analyzing the interval probability and return period in China. Full article
(This article belongs to the Special Issue Drought Monitoring, Forecasting, and Risk Assessment)
Figures

Figure 1

Open AccessArticle BMP Optimization to Improve the Economic Viability of Farms in the Upper Watershed of Miyun Reservoir, Beijing, China
Water 2017, 9(9), 633; doi:10.3390/w9090633
Received: 18 May 2017 / Revised: 18 July 2017 / Accepted: 21 July 2017 / Published: 24 August 2017
PDF Full-text (3680 KB) | HTML Full-text | XML Full-text
Abstract
Best management practices (BMPs) are being implemented to reduce non-point sources pollution in China and worldwide. There are many types of agricultural BMPs, but their effectiveness differs from farm to farm, depending on where they are applied, how they are applied, and how
[...] Read more.
Best management practices (BMPs) are being implemented to reduce non-point sources pollution in China and worldwide. There are many types of agricultural BMPs, but their effectiveness differs from farm to farm, depending on where they are applied, how they are applied, and how they are impacted by weather. Two farms (village Nan Wayao, VNWY and village Liu Jianfang, VLJF) with differing farm systems (crop-based mixed farm and dairy-based farms) located in the upper watershed of Miyun reservoir, Beijing, China were selected. We used the Integrated Farming System Model (IFSM) based on these two farms information to estimate total phosphorus (TP) and total nitrogen (TN) loss from 2000 to 2014, to identify (1) causes of farm nutrient imbalances, (2) key factors causing the imbalances, and (3) viable BMPs to reduce source and TN runoff at the farm scale. Results indicated that these farms had TP losses ranging from 8.2 to 160 kg/ha/year and TN losses from 73.7 to 1391.6 kg/ha/year. Using IFSM, physical (i.e., soil bulk density, available water content, and soil-P) and economic (i.e., diesel and farm loan interest rates) factors are more influential in determining nutrient loss from VNWY than VLJF. Rainfall patterns had a little effect on nutrient use and loss on the dairy farm in VLJF. Changes in available water content and soil bulk density had greater impact on the return for VNWY than VLJF, while changes in loan interest rates were more influential on VLJF. Maximum reductions in nutrient loss were obtained with implementation of the BMPs conservation tillage, reduced fertilizer and manure applications, buffer strips, and storage of poultry manure. Full article
(This article belongs to the collection Water Policy Collection)
Figures

Figure 1

Open AccessArticle Two Dimension Reduction Methods for Multi-Dimensional Dynamic Programming and Its Application in Cascade Reservoirs Operation Optimization
Water 2017, 9(9), 634; doi:10.3390/w9090634
Received: 16 July 2017 / Revised: 11 August 2017 / Accepted: 18 August 2017 / Published: 24 August 2017
PDF Full-text (2882 KB) | HTML Full-text | XML Full-text
Abstract
An efficient reservoir operation technique plays a very important role in improving the water resources and energy efficiency of reservoirs. In order to effectively avoid or alleviate the “curse of dimensionality” of Multi-dimensional Dynamic Programming (MDP) in the application of cascade reservoirs operation
[...] Read more.
An efficient reservoir operation technique plays a very important role in improving the water resources and energy efficiency of reservoirs. In order to effectively avoid or alleviate the “curse of dimensionality” of Multi-dimensional Dynamic Programming (MDP) in the application of cascade reservoirs operation optimization (CROO) and keep a global convergence at the same time, two dimension reduction methods are proposed in this paper. One is a hybrid algorithm of MDP and a Progressive Optimality Algorithm (POA), named MDP-POA, which combines the global convergence of MDP and the strong local search ability of POA. MDP-POA first takes the global optimal trajectory of MDP in a low discrete degree as the initial trajectory of the POA, and then implements further optimization to the obtained initial trajectory by the POA with a high discrete degree, so as to avoid the “curse of dimensionality” of MDP in high discrete degree and the dependency of the POA for the initial trajectory. The other is an improved MDP (IMDP), which first constructs a corridor by the optimal trajectory of MDP in a lower discrete degree, and then implements further optimization in the corridor by MDP with a relatively high discrete degree, so as to avoid a large number of unnecessary calculations, and shorten the run-time effectively. In a case study, the results of MDP-POA, IMDP, and MDP are compared and analyzed from the aspects of power generation and run-time. The analysis indicates that the proposed MDP-POA and IMDP both have a good application effect and are worthy of further promotion. Full article
Figures

Figure 1

Open AccessArticle Comparative Study on Influences of Bank Slope Ecological Revetments on Water Quality Purification Pretreating Low-Polluted Waters
Water 2017, 9(9), 636; doi:10.3390/w9090636
Received: 12 July 2017 / Revised: 4 August 2017 / Accepted: 21 August 2017 / Published: 24 August 2017
PDF Full-text (9959 KB) | HTML Full-text | XML Full-text
Abstract
To improve aquatic environmental quality and maintain channel stability against soil erosion, ecological bank slope revetments for surface water bodies were developed using a combination of prefabricated porous concrete spheres and vegetation methods, and a model set-up consisting of two equal-sized ditches with
[...] Read more.
To improve aquatic environmental quality and maintain channel stability against soil erosion, ecological bank slope revetments for surface water bodies were developed using a combination of prefabricated porous concrete spheres and vegetation methods, and a model set-up consisting of two equal-sized ditches with different types of bank slope revetments was constructed to evaluate the purification effects of ecological and hard revetments on water quality. The slope of one ditch was embanked with ecological revetments as an experimental treatment, while the other was embanked with hard revetments as a control. Pollutant removal from the ecological bank revetment ditch was significantly better in terms of the overall removal efficiencies of the chemical oxygen demand of manganese (CODMn), ammonia, total nitrogen (TN), and total phosphorus (TP), with two- to four-fold greater removal compared with that from hard slope revetments under the same operational conditions. Nutrient pollutants, including ammonia, TN, and TP had higher removal efficiencies than that for CODMn in both experimental ditches. The dependence of the first-order rate constant (k20) and temperature coefficient () obtained from the Arrhenius equation indicated that the removal efficiencies for ammonia, TN, and TP were higher with greater rate constants (k20) in the experimental ditch. In the ecological revetment ditch, the k20 values for CODMn, ammonia, TN, and TP were 0.054, 0.378, 0.222, and 0.266 respectively, around three-fold the values observed in the hard revetment ditch, but there was no obvious difference in values between the two ditches. The k20 values of TN and TP in both ditches showed significant positive correlations with seasonal shifts, as the removal of nutrient pollutants is highly sensitive to water temperatures. Full article
Figures

Figure 1

Open AccessArticle A Semi-Analytical Model for the Hydraulic Resistance Due to Macro-Roughnesses of Varying Shapes and Densities
Water 2017, 9(9), 637; doi:10.3390/w9090637
Received: 21 June 2017 / Revised: 27 July 2017 / Accepted: 21 August 2017 / Published: 25 August 2017
PDF Full-text (1675 KB) | HTML Full-text | XML Full-text
Abstract
A friction model resulting from investigations into macro-roughness elements in fishways has been compared with a broad range of studies in the literature under very different bed configurations. In the context of flood modelling or aquatic habitats, the aim of the study is
[...] Read more.
A friction model resulting from investigations into macro-roughness elements in fishways has been compared with a broad range of studies in the literature under very different bed configurations. In the context of flood modelling or aquatic habitats, the aim of the study is to show that the formulation is applicable to both emergent or submerged obstacles with either low or high obstacle concentrations. In the emergent case, the model takes into account free surface variations at large Froude numbers. In the submerged case, a vegetation model based on the double-averaging concept is used with a specific turbulence closure model. Calculation of the flow in the roughness elements gives the total hydraulic resistance uniquely as a function of the obstacles’ drag coefficient. The results show that the model is highly robust for all the rough beds tested. The averaged accuracy of the model is about 20% for the discharge calculation. In particular, we obtain the known values for the limiting cases of low confinement, as in the case of sandy beds. Full article
Figures

Figure 1

Open AccessArticle Experimental Study on Erosion and Sedimentation Patterns Downstream of a W-weir in a Sinusoidal Mild Bend
Water 2017, 9(9), 638; doi:10.3390/w9090638
Received: 18 June 2017 / Revised: 19 August 2017 / Accepted: 23 August 2017 / Published: 29 August 2017
PDF Full-text (3252 KB) | HTML Full-text | XML Full-text
Abstract
Erosion in river bends causes loss of agricultural lands, adjacent facilities, and fish habitat. W-weir structures are recommended for controlling and reducing soil erosion as well as developing habitat for fish and other aquatic organisms. This paper presents the results of an experimental
[...] Read more.
Erosion in river bends causes loss of agricultural lands, adjacent facilities, and fish habitat. W-weir structures are recommended for controlling and reducing soil erosion as well as developing habitat for fish and other aquatic organisms. This paper presents the results of an experimental study carried out to investigate the effect of a W-weir structure on a sinusoidal channel with a sinuosity of 1.12 on the scour volume and type. The W-weir was applied in three heights (0.5, 1, and 1.5) with H o / h ratio (the height of weir to flow depth ratio) and different hydraulic conditions (inflow Froude numbers 0.107, 0.142, and 0.178) tested for each structure. Bed topography was measured at the end of each experiment, and from that the types of scouring, maximum scour depth and length, as well as maximum ripple height and length were computed. Furthermore, by decreasing the height of W-weir from H o / h = 1.5 to H o / h = 0.5, the scour volume decreased from 24 to 78 percent on average for different inflow Froude numbers. The angle of inner arms of W-weir was chosen as 50°, 64°, 86°, and 124°. Minimum scour volume occurred in the angle of inner arms of w-weir 64° for different heights of W-weir tested. Finally, two scour morphologies were observed. This study provides insights to guide and design W-weir structures for river restoration projects. Full article
Figures

Figure 1

Open AccessArticle Simulink Implementation of a Hydrologic Model: A Tank Model Case Study
Water 2017, 9(9), 639; doi:10.3390/w9090639
Received: 15 June 2017 / Revised: 19 August 2017 / Accepted: 22 August 2017 / Published: 25 August 2017
PDF Full-text (4397 KB) | HTML Full-text | XML Full-text
Abstract
Simulink, an extension of MATLAB, is a graphics-based model development environment for system modeling and simulation. Simulink’s user-friendly features, including block (data process) and arrow (data transfer) objects, a large number of existing blocks, no need to write codes, and a drag and
[...] Read more.
Simulink, an extension of MATLAB, is a graphics-based model development environment for system modeling and simulation. Simulink’s user-friendly features, including block (data process) and arrow (data transfer) objects, a large number of existing blocks, no need to write codes, and a drag and drop interface, provide modelers with an easy development environment. In this study, a Tank model was developed using Simulink and applied to a rainfall-runoff simulation for a study watershed to demonstrate the potential of Simulink as a tool for hydrological analysis. In the example given here, the Tank model was extended by two sub-modules representing evapotranspiration and storage-runoff distribution. In addition, model pre- and post-processing, such as input data preparation and results plotting, was carried out in MATLAB. Moreover, model parameters were calibrated using MATLAB optimization tools without any additional programming for linking the calibration algorithms and the model. The graphical representation utilized in the Simulink version of the Tank model helped us to understand the hydrological interactions described in the model, and the modular structure of the program facilitated the addition of new modules and the modification of existing modules as needed. From the study, we found that Simulink could be a useful and convenient environment for hydrological analysis and model development. Full article
Figures

Figure 1

Open AccessArticle PEPSO: Reducing Electricity Usage and Associated Pollution Emissions of Water Pumps
Water 2017, 9(9), 640; doi:10.3390/w9090640
Received: 1 July 2017 / Revised: 20 August 2017 / Accepted: 21 August 2017 / Published: 26 August 2017
PDF Full-text (1459 KB) | HTML Full-text | XML Full-text
Abstract
Using metaheuristic optimization methods has enabled researchers to reduce the electricity consumption cost of small water distribution systems (WDSs). However, dealing with complicated WDSs and reducing their environmental footprint remains a challenge. In this study a multi-objective version of Pollution Emission Pump Station
[...] Read more.
Using metaheuristic optimization methods has enabled researchers to reduce the electricity consumption cost of small water distribution systems (WDSs). However, dealing with complicated WDSs and reducing their environmental footprint remains a challenge. In this study a multi-objective version of Pollution Emission Pump Station Optimization tool (PEPSO) is introduced that can reduce the electricity cost and pollution emissions (associated with the energy consumption) of pumps of WDSs. PEPSO includes a user-friendly graphical interface and a customized version of the non-dominated sorting genetic algorithm. A measure that is called “Undesirability Index” (UI) is defined to assist the search for a promising optimization path. The UI also ensures that the final results are desirable and practical. The various features of PEPSO are tested under six scenarios for optimizing the WDS of Monroe City, MI, and Richmond, UK. The test results indicate that in a reasonable amount of time, PEPSO can optimize and provide practical results for both WDSs. Full article
Figures

Open AccessArticle Geometry Defeaturing Effects in CFD Model-Based Assessment of an Open-Channel-Type UV Wastewater Disinfection System
Water 2017, 9(9), 641; doi:10.3390/w9090641
Received: 25 July 2017 / Revised: 13 August 2017 / Accepted: 25 August 2017 / Published: 27 August 2017
PDF Full-text (8517 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Computational fluid dynamics (CFD) is a popular tool in the water industry for assessing ultraviolet (UV) reactor performance. However, due to the size of open-channel-type UV reactor systems, the CFD model requires significant computational time. Thus, most evaluations have been conducted using very
[...] Read more.
Computational fluid dynamics (CFD) is a popular tool in the water industry for assessing ultraviolet (UV) reactor performance. However, due to the size of open-channel-type UV reactor systems, the CFD model requires significant computational time. Thus, most evaluations have been conducted using very simplified models. In order to ensure the reliability of this simplified CFD model, precise numerical modeling and validation by measurements are necessary considering the geometry defeaturing level. Therefore, simplified geometries in four defeatured levels were prepared for the CFD model, and simulations were performed to determine the level of geometric simplicity required to derive reliable results. A bioassay test was also conducted for a pilot-scale open-channel-type UV reactor that has the same geometrical configuration as the CFD model. Good agreement was observed between the bioassay test and CFD model results. It was found that the reduction equivalent dose (RED) is not significantly affected by geometry defeaturing under the assumption that the inlet flow conditions are relatively uniform. In multiple bank operation, the addition of banks yields a linear increment of the RED in the CFD model, however, a lower RED than the measured value was presented, especially for serial bank addition. The related aspects of the detailed flow physics and disinfection characteristics were also presented. These results are expected to provide useful information for CFD modeling, reactor design, and the assessment of the open-channel-type UV reactors. Full article
Figures

Figure 1

Open AccessArticle Numerical Investigation of the Influence of Water Jumping on the Local Scour beneath a Pipeline under Steady Flow
Water 2017, 9(9), 642; doi:10.3390/w9090642
Received: 11 June 2017 / Revised: 12 August 2017 / Accepted: 21 August 2017 / Published: 28 August 2017
PDF Full-text (5549 KB) | HTML Full-text | XML Full-text
Abstract
Rigid-lid approximation is usually used to replace the free surface in scour simulation. The influence of the rigid lid assumption on the prediction precision of scour hole in steady flow is studied in this paper. Firstly, a local scour model was constructed based
[...] Read more.
Rigid-lid approximation is usually used to replace the free surface in scour simulation. The influence of the rigid lid assumption on the prediction precision of scour hole in steady flow is studied in this paper. Firstly, a local scour model was constructed based on the open sources Computational Fluid Dynamics (CFD) model OpenFOAM, where both the bed load and suspended load were considered. In the present model, the bed shear stress was calculated by the Newton shear stress formula, instead of the traditional calculation method with the assumption that the flow velocity in vertical direction complies with a logarithmic distribution. The Volume of Fluid (VOF) method was used to capture the free surface and a moving-mesh method was used to track the change of bed surface. Then, several experiments were chosen to validate the model, and the modeling results fitted well with the measured data. Lastly, the effect of the rigid lid assumption on surface elevation, bed shear stress and the profile of the scour hole in steady flow are studied. The result shows that the surface elevation suffers a drop above the pipeline, and the difference of surface elevation between the upstream and downstream increases with decreasing dimensionless depth. Compared with the free surface condition, the bed shear stress and scour hole depth computed with the rigid lid approximation were underestimated. Full article
Figures

Figure 1

Open AccessArticle Enhanced Two Dimensional Hydrodynamic and Water Quality Model (CE-QUAL-W2) for Simulating Mercury Transport and Cycling in Water Bodies
Water 2017, 9(9), 643; doi:10.3390/w9090643
Received: 21 July 2017 / Revised: 15 August 2017 / Accepted: 21 August 2017 / Published: 28 August 2017
PDF Full-text (4488 KB) | HTML Full-text | XML Full-text
Abstract
CE-QUAL-W2 (W2) is a widely-used two-dimensional, laterally averaged, longitudinal/vertical, hydrodynamic and water quality model. This model was modified and enhanced to include a mercury (Hg) simulation module for simulating Hg transport and cycling in water bodies. The Hg simulation module in W2 is
[...] Read more.
CE-QUAL-W2 (W2) is a widely-used two-dimensional, laterally averaged, longitudinal/vertical, hydrodynamic and water quality model. This model was modified and enhanced to include a mercury (Hg) simulation module for simulating Hg transport and cycling in water bodies. The Hg simulation module in W2 is able to model the physical and biochemical processes including adsorption and desorption of Hg species on multi-solids, settling and resuspension, sediment burial of adsorbed Hg, diffusive exchange between water column and sediment layer, volatilization, and biogeochemical transformations among Hg species. This paper describes the Hg simulation module, W2 model validation and its application to the Xiaxi River, China, a historical Hg contaminated water body. The W2 model was evaluated using the Xiaxi River data collected in 2007 and 2008. Model results show that W2 was able to predict the total Hg and methylmercury concentrations observed for the Xiaxi River. The Xiaxi River W2 model also provides a foundation for the future investigations of Hg contamination in the Xiaxi River. This application demonstrated the W2 model capability in predicting complex transport and cycling of Hg species in water bodies. Full article
Figures

Figure 1

Open AccessArticle Hourly Water Level Forecasting at Tributary Affected by Main River Condition
Water 2017, 9(9), 644; doi:10.3390/w9090644
Received: 18 August 2017 / Revised: 18 August 2017 / Accepted: 21 August 2017 / Published: 28 August 2017
PDF Full-text (5543 KB) | HTML Full-text | XML Full-text
Abstract
This study develops hourly water level forecasting models with lead-times of 1 to 3 h using an artificial neural network (ANN) for Anyangcheon stream, one of the major tributaries of the Han River, South Korea. To consider the backwater effect from this river,
[...] Read more.
This study develops hourly water level forecasting models with lead-times of 1 to 3 h using an artificial neural network (ANN) for Anyangcheon stream, one of the major tributaries of the Han River, South Korea. To consider the backwater effect from this river, an enhanced tributary water level forecasting model is proposed by adding multiple water level data on the main river as input variables into the conventional ANN structure which often uses rainfall and upstream water level data. Four types of ANN models per each lead-time are built with increasing complexity of the input vector, and their performances are compared. The results indicate that the inclusion of multiple water level data on the main river to the network provides water level forecasts with greater accuracy at the Ogeumgyo gauging station of interest. The final best ANN models for water level forecasts with lead-times of 1 to 2 h show good performance with root mean square errors (RMSE) below 0.06 m and 0.12 m, respectively. However, the final best ANN model for forecasting 3 h ahead was unsatisfactory, showing underestimation at many rising parts of the hydrograph. Full article
Figures

Figure 1

Open AccessArticle Study of Self-Induced Sloshing in Model Test of a Water Retaining Weir
Water 2017, 9(9), 646; doi:10.3390/w9090646
Received: 11 July 2017 / Revised: 20 August 2017 / Accepted: 25 August 2017 / Published: 30 August 2017
PDF Full-text (5706 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents for the first time observations of a self-induced sloshing phenomenon in the water-retaining weir model. Fast Fourier Transform method is used to detect the dominant frequency for the sloshing water. The characteristics of the sloshing water in terms of sloshing
[...] Read more.
This paper presents for the first time observations of a self-induced sloshing phenomenon in the water-retaining weir model. Fast Fourier Transform method is used to detect the dominant frequency for the sloshing water. The characteristics of the sloshing water in terms of sloshing strength and frequency are experimentally studied for six different cases. Results show that both sloshing regions and sloshing strength depends on not only the water levels but also the inlet velocities, and the relationship between them is displayed in this paper. Different prediction models for sloshing frequencies are built and compared with the experimental results, with discussions of the differences between them. For higher water level sloshing region, a new factor is introduced to the Faltinsen’s prediction formula, leading to a better agreement between prediction and experimental results. The mechanism of the self-induced sloshing is also discussed in this paper. Full article
Figures

Figure 1

Open AccessArticle Integrating Topography and Soil Properties for Spatial Soil Moisture Storage Modeling
Water 2017, 9(9), 647; doi:10.3390/w9090647
Received: 14 July 2017 / Revised: 15 August 2017 / Accepted: 24 August 2017 / Published: 30 August 2017
PDF Full-text (4108 KB) | HTML Full-text | XML Full-text
Abstract
The understanding of the temporal and spatial dynamics of soil moisture and hydraulic property of soil is crucial to the study of hydrological and ecological processes. The purpose of this study was to derive equations that describe spatial soil water storage deficit based
[...] Read more.
The understanding of the temporal and spatial dynamics of soil moisture and hydraulic property of soil is crucial to the study of hydrological and ecological processes. The purpose of this study was to derive equations that describe spatial soil water storage deficit based on topography and soil properties. This storage deficit together with the topographical index can be used to conclude the spatial distribution curve of storage capacity in a (sub-) basin for developing hydrological model. The established model was able to match spatial and temporal variations of water balance components (i.e., soil moisture content (SMC), evapotranspiration, and runoff) over the Ziluoshan basin. Explicit expression of the soil moisture storage capacity (SMSC) in the model reduced parameters, which provides a method for hydrological simulation in ungauged basins. Full article
(This article belongs to the Special Issue Soil Water Conservation: Dynamics and Impact)
Figures

Figure 1

Open AccessArticle Stimulating Learning through Policy Experimentation: A Multi-Case Analysis of How Design Influences Policy Learning Outcomes in Experiments for Climate Adaptation
Water 2017, 9(9), 648; doi:10.3390/w9090648
Received: 31 May 2017 / Revised: 20 July 2017 / Accepted: 10 August 2017 / Published: 30 August 2017
Cited by 1 | PDF Full-text (901 KB) | HTML Full-text | XML Full-text
Abstract
Learning from policy experimentation is a promising way to approach the “wicked problem” of climate adaptation, which is characterised by knowledge gaps and contested understandings of future risk. However, although the role of learning in shaping public policy is well understood, and experiments
[...] Read more.
Learning from policy experimentation is a promising way to approach the “wicked problem” of climate adaptation, which is characterised by knowledge gaps and contested understandings of future risk. However, although the role of learning in shaping public policy is well understood, and experiments are expected to facilitate learning, little is known about how experiments produce learning, what types of learning, and how they can be designed to enhance learning effects. Using quantitative research methods, we explore how design choices influence the learning experiences of 173 participants in 18 policy experiments conducted in the Netherlands between 1997 and 2016. The experiments are divided into three “ideal types” that are expected to produce different levels and types of learning. The findings show that policy experiments produce cognitive and relational learning effects, but less normative learning, and experiment design influenced three of six measured dimensions of learning, especially the cognitive learning dimensions. This reveals a trade-off between designing for knowledge development and designing for normative or relational changes; choices that experiment designers should make in the context of their adaptation problem. Our findings also show the role leadership plays in building trust. Full article
(This article belongs to the Special Issue Adaptation Strategies to Climate Change Impacts on Water Resources)
Figures

Figure 1

Open AccessArticle Long-Term Assessment of Climate Change Impacts on Tennessee Valley Authority Reservoir Operations: Norris Dam
Water 2017, 9(9), 649; doi:10.3390/w9090649
Received: 6 February 2017 / Revised: 25 July 2017 / Accepted: 25 August 2017 / Published: 30 August 2017
PDF Full-text (2263 KB) | HTML Full-text | XML Full-text
Abstract
Norris Reservoir is the oldest and largest reservoir maintained and operated by the Tennessee Valley Authority (TVA). Norris Dam received a new operating guide in 2004; however, this new guide did not consider projected climate change. In an aging infrastructure, the necessity to
[...] Read more.
Norris Reservoir is the oldest and largest reservoir maintained and operated by the Tennessee Valley Authority (TVA). Norris Dam received a new operating guide in 2004; however, this new guide did not consider projected climate change. In an aging infrastructure, the necessity to assess the potential impacts of climate change on water resources planning and management is increasing. This study used a combined monthly hydrologic model and a general circulation model’s (GCM) outcome to project inflows for three future time spans: 2030s, 2050s, and 2070s. The current operating guide was then assessed and optimized using penalty-function-driven genetic algorithms to gain insight for how the current guide will respond to climate change, and if it can be further optimized. The results showed that the current operating guide could sufficiently handle the increased projected runoff without major risk of dam failure or inundation, but the optimized operating guides decreased operational penalties ranging from 22 to 37 percent. These findings show that the framework used here provides water resources planning and management a methodology for assessing and optimizing current systems, and emphasizes the need to consider projected climate change as an assessment tool for reservoir operations. Full article
Figures

Figure 1

Open AccessArticle Atoll Groundwater Movement and Its Response to Climatic and Sea-Level Fluctuations
Water 2017, 9(9), 650; doi:10.3390/w9090650
Received: 26 July 2017 / Revised: 19 August 2017 / Accepted: 22 August 2017 / Published: 30 August 2017
Cited by 1 | PDF Full-text (6935 KB) | HTML Full-text | XML Full-text
Abstract
Groundwater resources of low-lying atoll islands are threatened due to short-term and long-term changes in rainfall, wave climate, and sea level. A better understanding of how these forcings affect the limited groundwater resources was explored on Roi-Namur in the Republic of the Marshall
[...] Read more.
Groundwater resources of low-lying atoll islands are threatened due to short-term and long-term changes in rainfall, wave climate, and sea level. A better understanding of how these forcings affect the limited groundwater resources was explored on Roi-Namur in the Republic of the Marshall Islands. As part of a 16-month study, a rarely recorded island-overwash event occurred and the island’s aquifer’s response was measured. The findings suggest that small-scale overwash events cause an increase in salinity of the freshwater lens that returns to pre-overwash conditions within one month. The overwash event is addressed in the context of climate-related local sea-level change, which suggests that overwash events and associated degradations in freshwater resources are likely to increase in severity in the future due to projected rises in sea level. Other forcings, such as severe rainfall events, were shown to have caused a sudden freshening of the aquifer, with salinity levels retuning to pre-rainfall levels within three months. Tidal forcing of the freshwater lens was observed in electrical resistivity profiles, high-resolution conductivity, groundwater-level well measurements and through submarine groundwater discharge calculations. Depth-specific geochemical pore water measurements further assessed and confirmed the distinct boundaries between fresh and saline water masses in the aquifer. The identification of the freshwater lens’ saline boundaries is essential for a quantitative evaluation of the aquifers freshwater resources and help understand how these resources may be impacted by climate change and anthropogenic activities. Full article
Figures

Figure 1

Open AccessArticle Preparation of a Thermally Modified Diatomite and a Removal Mechanism for 1-Naphthol from Solution
Water 2017, 9(9), 651; doi:10.3390/w9090651
Received: 28 June 2017 / Revised: 11 August 2017 / Accepted: 28 August 2017 / Published: 30 August 2017
PDF Full-text (3551 KB) | HTML Full-text | XML Full-text
Abstract
The adsorption of 1-naphthol (NAP) in aqueous solution was investigated using unmodified and modified diatomite at different temperature, pH, adsorbent mass and contact time. The adsorption capacity of the modified diatomite significantly improved (about 2 times at 298 K) compared to the unmodified
[...] Read more.
The adsorption of 1-naphthol (NAP) in aqueous solution was investigated using unmodified and modified diatomite at different temperature, pH, adsorbent mass and contact time. The adsorption capacity of the modified diatomite significantly improved (about 2 times at 298 K) compared to the unmodified diatomite. The adsorption showed a good fit with the Langmuir model. The further data analysis demonstrated that the adsorption of 1-NAP on both materials could be best described by the pseudo second-order kinetic model. The thermodynamic parameters, including Gibbs’ free energy (ΔG), enthalpy (ΔH) and entropy changes (ΔS) were determined. It was observed that the ΔH values (less than 40 kJ/mol) was positive, which indicated that the adsorption process is endothermic, physical adsorption. The ΔG values were negative, indicating that the adsorption of 1-NAP onto raw and modified adsorbent was spontaneous. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Spatio-Temporal Patterns of the 2010–2015 Extreme Hydrological Drought across the Central Andes, Argentina
Water 2017, 9(9), 652; doi:10.3390/w9090652
Received: 1 June 2017 / Revised: 19 August 2017 / Accepted: 23 August 2017 / Published: 30 August 2017
PDF Full-text (8350 KB) | HTML Full-text | XML Full-text
Abstract
During the period 2010–2015, the semi-arid Central Andes in Argentina (CAA) experienced one of the most severe and long-lasting hydrological droughts on record. Since the snowmelt is the most important source of water, the reduced snowfall over the mountains propagated the drought signal
[...] Read more.
During the period 2010–2015, the semi-arid Central Andes in Argentina (CAA) experienced one of the most severe and long-lasting hydrological droughts on record. Since the snowmelt is the most important source of water, the reduced snowfall over the mountains propagated the drought signal through the streamflows in the adjacent foothills east of the Andes ranges. Motivated by the widespread impacts on the socio-economic activities in the region, this study aims to characterize the recent hydrological drought in terms of streamflow deficits. Based on streamflow data from 20 basins, we used the standardized streamflow index (SSI) to characterize hydrological droughts during the period 1971–2016. We found that the regional extent of the 2010–2015 hydrological drought was limited to the basins located north of 38° S, with mean duration of 67 months and maximum drought severity exhibiting a heterogeneous pattern in terms of spatial distribution and time of occurrence. The drought event reached extreme conditions in 14 of the 15 basins in the CAA, being record-breaking drought in six of the basins. This condition was likely driven by a cooling in the tropical Pacific Ocean resembling La Niña conditions, which generated a decrease in snowfall over the Andes due to suppressed frontal activity. Full article
(This article belongs to the Special Issue Drought Monitoring, Forecasting, and Risk Assessment)
Figures

Figure 1

Open AccessArticle Design of Indicators of Circular Economy as Instruments for the Evaluation of Sustainability and Efficiency in Wastewater from Pig Farming Industry
Water 2017, 9(9), 653; doi:10.3390/w9090653
Received: 26 July 2017 / Revised: 20 August 2017 / Accepted: 28 August 2017 / Published: 31 August 2017
Cited by 1 | PDF Full-text (964 KB) | HTML Full-text | XML Full-text
Abstract
Circular economy intends to turn waste into resources that can be reintroduced into the production process, eliminating the negative externalities from it. The impact of pig manure on the environment is one of the main challenges in agriculture. The high amount of pig
[...] Read more.
Circular economy intends to turn waste into resources that can be reintroduced into the production process, eliminating the negative externalities from it. The impact of pig manure on the environment is one of the main challenges in agriculture. The high amount of pig manure coming from the pig farming industry complicates the management of this type of effluents, leading to a serious impact on the environment, as it pollutes the soil, the water, and the air. The concept of the indicator of circular economy was introduced to evaluate the degree of approximation of the pig manure treatment process to the circular economy model. In light of this, these indicators showed the possibility of obtaining 0.97 m3 water h−1, 49.40 kg biofertilizer h−1, and 5.33 m3 biogas h−1 per 1 m3 pig manure h−1 treated, allowing us to assess the minimization of waste generation and the efficiency of the use of resources. By applying an anaerobic digestion process to treat pig manure, reductions of water and natural gas consumptions were 47.01% and 5.33%, respectively, which leads to a reduction in emissions of 171.98 kg CO2 h−1. Consequently, pig manure can be considered as a technological nutrient that is reintroduced into the productive system, enabling the recovery of energy, water, and biofertilizer contained therein. Full article
Figures

Figure 1

Open AccessArticle Computational Modeling of Flow and Scour around Two Cylinders in Staggered Array
Water 2017, 9(9), 654; doi:10.3390/w9090654
Received: 26 July 2017 / Revised: 24 August 2017 / Accepted: 28 August 2017 / Published: 31 August 2017
PDF Full-text (11129 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a numerical study on flow and local scour around two identical cylinders with diverse spacing ratios (s/D) and alignment angles (α). The spacing ratio of center-to-center distance between cylinders (s) to the
[...] Read more.
This paper presents a numerical study on flow and local scour around two identical cylinders with diverse spacing ratios (s/D) and alignment angles (α). The spacing ratio of center-to-center distance between cylinders (s) to the cylinder diameter (D) varied from 1.25 to 5.0, including five alignment angles ranged from 0° to 90°. The detailed scour processes and information were obtained in a physics-based way by using large eddy simulation coupled with sediment transport in a Lagrangian framework and a morphodynamic model. Turbulent flow properties around two cylinders in staggered array are significantly concerned by the spacing ratio and the alignment angle which reflect complex features of evolution of scour and scour depth. The computed results exhibited the scour depth is associated with the spacing ratio and alignment angles especially at the rear cylinder. For small alignment angles, the growth rate at the rear cylinder increased as the spacing ratio increased, due to a decrease in shielding effect. As the alignment angle increased, the scour depth around the rear cylinder increased until the angle reached approximately 45°–60°. Subsequently, the scour depth decreased with the alignment angle. It also revealed that the spacing ratio was more sensitive to the maximum scour than that of the alignment angle. For (s-D)/D > 2.0, the maximum scour depth only depended on the spacing ratio. Full article
Figures

Figure 1

Open AccessArticle Challenges to Water Security along the “Emerald Coast”: A Political Ecology of Local Water Governance in Nicaragua
Water 2017, 9(9), 655; doi:10.3390/w9090655
Received: 17 July 2017 / Revised: 18 August 2017 / Accepted: 24 August 2017 / Published: 31 August 2017
PDF Full-text (1580 KB) | HTML Full-text | XML Full-text
Abstract
Despite being a water-rich country, Nicaragua struggles to secure clean water access for many of its residents. In addition to distributional and water quality issues, a prolonged drought affecting all regions of the country has compounded preexisting governance challenges to ensuring rural water
[...] Read more.
Despite being a water-rich country, Nicaragua struggles to secure clean water access for many of its residents. In addition to distributional and water quality issues, a prolonged drought affecting all regions of the country has compounded preexisting governance challenges to ensuring rural water needs. This article focuses on a rural community along the southwest Pacific Coast of Tola, Nicaragua, where tourism development and drought converge to produce and exacerbate water insecurity. This article examines this water insecurity in the context of two recent national water laws in Nicaragua (passed in 2007 and 2010 respectively) that sought to provide a more comprehensive legal framework for freshwater water governance. Drawing upon semi-structured interviews and groundwater and meteorological data, we contend that water laws have not effectively mediated the hydrological effects of prolonged drought and tourism development, resulting in pronounced water insecurity for local populations in Tola. We cast the findings of this research as relevant to other water insecure areas in Latin America where industry development and weak policy implementation impact the creation and resolution of local water security—including insecurity compounded by increased climatic variability. Full article
(This article belongs to the collection Water Policy Collection)
Figures

Figure 1

Open AccessFeature PaperArticle Effect of Roughness on Conservative Solute Transport through Synthetic Rough Single Fractures
Water 2017, 9(9), 656; doi:10.3390/w9090656
Received: 31 July 2017 / Revised: 26 August 2017 / Accepted: 29 August 2017 / Published: 1 September 2017
PDF Full-text (5653 KB) | HTML Full-text | XML Full-text
Abstract
Understanding solute transport in fractured rocks is of particular importance in many applications. Aperture values ranging from 4.7 to 8.7 mm and Reynolds number (Re) values at 9.38~1743.8 were set for investigating fluid flow through synthetic horizontal single smooth and
[...] Read more.
Understanding solute transport in fractured rocks is of particular importance in many applications. Aperture values ranging from 4.7 to 8.7 mm and Reynolds number (Re) values at 9.38~1743.8 were set for investigating fluid flow through synthetic horizontal single smooth and rough fractures. The Brilliant Blue FCF dye was chosen as the tracer to visualize the transport process. This paper focuses on the dispersion process in rough single fractures under non-Darcian flow conditions. Non-Darcian flow existed in both smooth and rough single fractures and the average flow velocity–hydraulic gradient (VJ) relationships were best described by the Forchheimer equation. The main objectives were to check the existing flow and transport models and to study possible correlations between fitting parameters and heterogeneities. The classical advection dispersion equation (ADE) model failed to capture the long-tailing of breakthrough curves (BTCs). Instead, the continuous time random walk (CTRW) model was better at explaining BTCs in both smooth and rough fractures, especially in capturing the long-tailing feature. The non-Darcian coefficient βc in the Forchheimer equation and the coefficient β in the CTRW model appeared to be most relevant for characterizing the heterogeneity of the rough single fractures. Full article
Figures

Figure 1

Open AccessArticle Coupling the Modified Linear Spectral Mixture Analysis and Pixel-Swapping Methods for Improving Subpixel Water Mapping: Application to the Pearl River Delta, China
Water 2017, 9(9), 658; doi:10.3390/w9090658
Received: 7 July 2017 / Revised: 24 August 2017 / Accepted: 25 August 2017 / Published: 1 September 2017
PDF Full-text (20154 KB) | HTML Full-text | XML Full-text
Abstract
High-resolution water mapping with remotely sensed data is essential to monitoring of rainstorm waterlogging and flood disasters. In this study, a modified linear spectral mixture analysis (LSMA) method is proposed to extract high-precision water fraction maps. In the modified LSMA, the pure water
[...] Read more.
High-resolution water mapping with remotely sensed data is essential to monitoring of rainstorm waterlogging and flood disasters. In this study, a modified linear spectral mixture analysis (LSMA) method is proposed to extract high-precision water fraction maps. In the modified LSMA, the pure water and mixed water-land pixels, which are extracted by the Otsu method and a morphological dilation operation, are used to improve the accuracy of water fractions. The modified LSMA is applied to the 18 October 2015 Landsat 8 OLI image of the Pearl River Delta for the extraction of water fractions. Based on the water fraction maps, a modified subpixel mapping method (MSWM) based on a pixel-swapping algorithm is proposed for obtaining the spatial distribution information of water at subpixel scale. The MSWM includes two steps in subpixel water mapping. The MSWM considers the inter-subpixel/pixel and intra-subpixel/subpixel spatial attractions. Subpixel water mapping is first implemented with the inter-subpixel/pixel spatial attractions, which are estimated using the distance between a given subpixel and its surrounding pixels and the water fractions of the surrounding pixels. Based on the initialized subpixel water mapping results, the final subpixel water maps are determined by a modified pixel-swapping algorithm, in which the intra-subpixel/subpixel spatial attractions are estimated using the initialized subpixel water maps and an inverse-distance weighted function of the current subpixel at the centre of a moving window with its surrounding subpixels within the window. The subpixel water mapping performance of the MSWM is compared with that of subpixel mapping for linear objects (SPML) and that of the subpixel/pixel spatial attraction model (SPSAM) using the GF-1 reference image from 20 October 2015. The experimental results show that the MSWM shows better subpixel water mapping performance and obtains more details than SPML and SPSAM, as it has the largest overall accuracy values and Kappa coefficients. Furthermore, the MSWM can significantly eliminate the phenomenon of jagged edges and has smooth continuous edges. Full article
Figures

Figure 1

Open AccessArticle Methane Emissions in Spanish Saline Lakes: Current Rates, Temperature and Salinity Responses, and Evolution under Different Climate Change Scenarios
Water 2017, 9(9), 659; doi:10.3390/w9090659
Received: 2 August 2017 / Revised: 24 August 2017 / Accepted: 28 August 2017 / Published: 1 September 2017
PDF Full-text (2279 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Wetlands are among the most biologically active ecosystems on Earth, playing an important role in the global carbon cycle. Methane production in wetlands, resulting from anaerobic respiration of organic matter, accounts for an important part of natural sources of methane. In this work,
[...] Read more.
Wetlands are among the most biologically active ecosystems on Earth, playing an important role in the global carbon cycle. Methane production in wetlands, resulting from anaerobic respiration of organic matter, accounts for an important part of natural sources of methane. In this work, we have evaluated the methane release rates of saline shallow lakes located in Central Spain, some of which maintain natural conditions, whereas others are hydrologically altered, with lowered salinity, or even presenting trophic alterations. We used sediment core plus water incubations to determine the release of methane from the studied lakes to the atmosphere, integrating both diffusion and ebullition processes, as well as the effects of temperature and salinity on methane production. The studied hypersaline lakes released methane at rates within the lowest range reported for temperate lakes and wetlands, whereas in hydrologically altered lakes that have dropped their salinity these rates were markedly higher. Models built with the specific response of methane release rates to temperature regarding the temperature changes expected according to the RCP climate scenarios predicted significant increases of these rates for the future, which could almost double current methane release for some of the studied lakes under the most pessimistic mitigation scenario (RCP8.5). Full article
(This article belongs to the Special Issue Ecological Responses of Lakes to Climate Change)
Figures

Figure 1

Open AccessArticle Changes of Permeability of Nonwoven Geotextiles due to Clogging and Cyclic Water Flow in Laboratory Conditions
Water 2017, 9(9), 660; doi:10.3390/w9090660
Received: 1 August 2017 / Revised: 23 August 2017 / Accepted: 30 August 2017 / Published: 1 September 2017
PDF Full-text (5472 KB) | HTML Full-text | XML Full-text
Abstract
The use of geotextile filters has been a common application in geo-environmental and geotechnical engineering for decades. The purpose of the present paper is to assess the influence of artificial physical clogging and cyclic water flow on the water permeability characteristics of nonwoven
[...] Read more.
The use of geotextile filters has been a common application in geo-environmental and geotechnical engineering for decades. The purpose of the present paper is to assess the influence of artificial physical clogging and cyclic water flow on the water permeability characteristics of nonwoven geotextiles used commonly in filter and drainage systems. Despite many studies examining the behavior of soil-geosynthetics, the mechanism of physical clogging is not fully understood yet and remains incompletely defined. Artificial clogging and cyclic water flow tests have been conducted according to a procedure created by the authors. Three nonwoven geotextiles and silty sand were employed in the test series. Hydraulic properties of the tested geosynthetics were determined according to the ISO standard. Filter design criteria are also discussed. The paper also presents the changes of water permeability characteristics due to clogging and cyclic water flow. The results show significant decrease of water permeability coefficients of the tested nonwoven geotextiles after artificial clogging and under cyclic water flow. Furthermore, the clogging mechanism was observed and confirmed by three-dimensional computed tomography. Full article
Figures

Figure 1

Open AccessArticle Effect by Alkaline Flocculation of Algae and Phosphorous from Water Using a Calcined Waste Oyster Shell
Water 2017, 9(9), 661; doi:10.3390/w9090661
Received: 7 August 2017 / Revised: 16 August 2017 / Accepted: 30 August 2017 / Published: 6 September 2017
PDF Full-text (2317 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Alkaline flocculation has been considered as a potential candidate to remove algae and eutrophic substances from water. A number of researches using low-cost and environmentally friendly methods have been suggested to optimize removal efficiency. In this study, a calcium-containing waste oyster shell, as
[...] Read more.
Alkaline flocculation has been considered as a potential candidate to remove algae and eutrophic substances from water. A number of researches using low-cost and environmentally friendly methods have been suggested to optimize removal efficiency. In this study, a calcium-containing waste oyster shell, as an environmentally friendly substance, has been used to treat phosphorous, a eutrophic substance, and to remove algae from the fresh water simultaneously. The X-ray Fluorescence (XRF) analysis showed that CaO was a major phase in a raw oyster shell, which played an important role for flocculation of phosphorous as well as algae. In order to eliminate the algae or phosphorous effectively, oyster shell was calcined at 1000 °C and hydrated in water. The slurry of hydrated calcined oyster shell, from 5 g/L to 12.5 g/L, was utilized in this experiment, where the experimental results were compared with that of dolomite. A series of experimental investigations, such as pH and turbidity changes using the water quality analyzer and UV-Visible spectroscopy (UV-Vis), demonstrated that the algae were efficiently removed. In addition, total phosphorous (TP) and total nitrogen (TN) analyses at different amounts of slurries of the hydrated calcined oyster shell showed that almost all the phosphorous was removed at 7.5 g/L of hydrated oyster shell, but due to the high solubility of nitrogen compounds, no obvious effect for the removal of nitrogen was observed. Furthermore, powder X-ray diffractions (PXRD) showed that Ca(OH)2 compounds were transformed to the phosphate compound, suggesting that the oyster shell caused flocculation by chemically forming with phosphorous ions. Full article
Figures

Figure 1

Open AccessArticle Legionella Survey in the Plumbing System of a Sparse Academic Campus: A Case Study at the University of Perugia
Water 2017, 9(9), 662; doi:10.3390/w9090662
Received: 30 June 2017 / Revised: 5 August 2017 / Accepted: 29 August 2017 / Published: 1 September 2017
PDF Full-text (1859 KB) | HTML Full-text | XML Full-text
Abstract
We have monitored the presence of bacteria belonging to the genus Legionella in the plumbing of buildings at the University of Perugia (Italy). More than 300 water samples were collected from 156 control-point taps in 41 buildings comprised in the eight campuses of
[...] Read more.
We have monitored the presence of bacteria belonging to the genus Legionella in the plumbing of buildings at the University of Perugia (Italy). More than 300 water samples were collected from 156 control-point taps in 41 buildings comprised in the eight campuses of the University. Legionella was absent in most samples, while it was found in only 12 buildings (29% of the total). Molecular analysis indicated the presence of L. pneumophila (serogroups 1, 8 and 6–10), L. taurinensis and L. anisa. In only three cases contamination levels were above the limit at which remedial actions are required, according to international guidelines. In two buildings, where the water temperature could be raised and maintained above 60 °C, thermal disinfection was effective in eradicating Legionella. Conversely, in buildings where contaminations were caused by heat exchangers that produced hot water at a maximum temperature of 50 °C, a chemical disinfection with silver hydrogen peroxide was carried out but was effective only in the short term. In this case study, Legionella contaminations and remediation effectiveness strongly depended on the network and heating-system characteristics, indicating how a multidisciplinary approach that integrates microbiological analysis with hydraulic surveys is necessary for an effective definition of Legionella prevention and control strategies. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Modelling Extreme Wave Overtopping at Aberystwyth Promenade
Water 2017, 9(9), 663; doi:10.3390/w9090663
Received: 29 June 2017 / Accepted: 24 August 2017 / Published: 14 September 2017
PDF Full-text (3566 KB) | HTML Full-text | XML Full-text
Abstract
The work presents a methodology to assess the coastal impacts during a storm event which caused significant damage along the promenade at Aberystwyth, Wales on the 3 January 2014. Overtopping was analysed in detail for a section of promenade by downscaling offshore wave
[...] Read more.
The work presents a methodology to assess the coastal impacts during a storm event which caused significant damage along the promenade at Aberystwyth, Wales on the 3 January 2014. Overtopping was analysed in detail for a section of promenade by downscaling offshore wave conditions to force a surf zone hydrodynamic model, NEWRANS. Overtopping discharges are computed and were in qualitative agreement with published discharges for the level of damage observed along the promenade. Peak storm conditions were observed to arrive just before and during high tide at Aberystwyth, which in addition to a storm surge and wave-setup, contributed to the damage observed. A high frequency of overtopping occurs during peak high tide, with overtopping also occurring in the hour leading up to and following high tide. Finally, comparisons to design methods for the estimation of overtopping discharge were made. Current empirical formulae underestimated the peak overtopping event at high tide. The methodology applied is generic and applicable to any location. Full article
Figures

Figure 1

Open AccessArticle The Effect of a Spiral Gradient Magnetic Field on the Ionic Conductivity of Water
Water 2017, 9(9), 664; doi:10.3390/w9090664
Received: 23 June 2017 / Revised: 21 August 2017 / Accepted: 31 August 2017 / Published: 2 September 2017
PDF Full-text (1888 KB) | HTML Full-text | XML Full-text
Abstract
We discuss the experimental verification of changes in the structure of a liquid water sample inserted in a special spiral “gradient” magnetic field. The magnetic flux components are characterized by a high degree of inhomogeneity; thus, a gradient is found in the monitored
[...] Read more.
We discuss the experimental verification of changes in the structure of a liquid water sample inserted in a special spiral “gradient” magnetic field. The magnetic flux components are characterized by a high degree of inhomogeneity; thus, a gradient is found in the monitored section of space. The relevant measurement of the modified, rearranged water sample pointed to a specific ion conductivity lower than that of the untreated water. The results of the experiment, where a sample of demineralized water was exposed to a spiral “gradient“ magnetic field for the period of 5 min, show decreased ion conductivity in the examined samples. Full article
(This article belongs to the Special Issue Electrohydrodynamic Liquid Bridges and Electrified Water)
Figures

Figure 1

Open AccessArticle Modeling the Dispersion of E. coli in Waterbodies Due to Urban Sources: A Spatial Approach
Water 2017, 9(9), 665; doi:10.3390/w9090665
Received: 7 August 2017 / Revised: 17 August 2017 / Accepted: 29 August 2017 / Published: 2 September 2017
PDF Full-text (2420 KB) | HTML Full-text | XML Full-text
Abstract
In the United States, pathogens are the leading cause for rivers and streams to exceed water quality standards. The Spatially Explicit Load Enrichment Calculation Tool (SELECT) was developed to estimate bacterially contaminated water bodies based on spatial factors such as land use, soil,
[...] Read more.
In the United States, pathogens are the leading cause for rivers and streams to exceed water quality standards. The Spatially Explicit Load Enrichment Calculation Tool (SELECT) was developed to estimate bacterially contaminated water bodies based on spatial factors such as land use, soil, and population density. SELECT was originally automated using Visual Basics for Applications (VBA), which is no longer supported by the current version of ArcGIS. The aim of this research was to develop a new SELECT interface, pySELECT, using the Python programming language and to incorporate a rainfall-runoff E. coli transport module to simulate E. coli loads resulting from urban sources, such as dogs and on-site wastewater treatment systems. The pySELECT tool was applied to Lavon Lake, a semi urban study watershed in Northeast Texas. The highest potential E. coli loads were in the areas closest to the Dallas-Fort Worth metroplex, and the highest transported loads were located downstream from those identified hotspots or where the most runoff was generated. Watershed managers can use pySELECT to develop best management practices on the specific areas and fecal sources that contribute fecal contamination into a waterbody. Full article
Figures

Figure 1

Open AccessArticle Identification of the Factors Influencing the Baseflow in the Permafrost Region of the Northeastern Qinghai-Tibet Plateau
Water 2017, 9(9), 666; doi:10.3390/w9090666
Received: 4 August 2017 / Revised: 1 September 2017 / Accepted: 1 September 2017 / Published: 6 September 2017
PDF Full-text (3667 KB) | HTML Full-text | XML Full-text
Abstract
Baseflow is an essential component of river runoff. Accurate measurements and analyses of baseflow change are challenging in permafrost-covered regions. In this paper, the upper reaches of the Shule River were selected as the study area, in which to study the baseflow change
[...] Read more.
Baseflow is an essential component of river runoff. Accurate measurements and analyses of baseflow change are challenging in permafrost-covered regions. In this paper, the upper reaches of the Shule River were selected as the study area, in which to study the baseflow change regulation and causes. The variable infiltration capacity (VIC) model, based on the ARNO baseflow formulation, was used to simulate the baseflow. Simulated baseflow was validated by the isotopic baseflow separation results and measured runoff in the recession periods throughout an entire year. It was found that approximately 63.1% of the river runoff was sourced by baseflow in the study region; the baseflow change was relatively smooth throughout the year, and it lagged a few days behind the river runoff. Approximately 80% of the total baseflow was generated in the 3500–4500 m alpine regions, with mainly low-temperature and mid-temperature permafrost. Based on the climate, runoff, land use, soil temperature and moisture data of the permafrost active layer, the mechanism of baseflow change in the permafrost zone was analysed. Precipitation and temperature positively enhanced the baseflow in the permafrost region throughout a year, but the baseflow was more influenced by the temperature than precipitation. In the study area, the cold desert and alpine grassland had the largest regulation capacity for baseflow. Affected by the permafrost freeze-thaw process, a baseflow peak occurred in the spring and the baseflow recession slowed in the autumn. This lead to a more uniform distribution of baseflow and runoff throughout the year. Full article
Figures

Figure 1

Open AccessArticle Assessing Thermally Stressful Events in a Rhode Island Coldwater Fish Habitat Using the SWAT Model
Water 2017, 9(9), 667; doi:10.3390/w9090667
Received: 30 June 2017 / Revised: 23 August 2017 / Accepted: 29 August 2017 / Published: 4 September 2017
PDF Full-text (3792 KB) | HTML Full-text | XML Full-text
Abstract
It has become increasingly important to recognize historical water quality trends so that the future impacts of climate change may be better understood. Climate studies have suggested that inland stream temperatures and average streamflow will increase over the next century in New England,
[...] Read more.
It has become increasingly important to recognize historical water quality trends so that the future impacts of climate change may be better understood. Climate studies have suggested that inland stream temperatures and average streamflow will increase over the next century in New England, thereby putting aquatic species sustained by coldwater habitats at risk. In this study we evaluated two different approaches for modeling historical streamflow and stream temperature in a Rhode Island, USA, watershed with the Soil and Water Assessment Tool (SWAT), using (i) original SWAT and (ii) SWAT plus a hydroclimatological model component that considers both hydrological inputs and air temperature. Based on daily calibration results with six years of measured streamflow and four years of stream temperature data, we examined occurrences of stressful conditions for brook trout (Salvelinus fontinalis) using the hydroclimatological model. SWAT with the hydroclimatological component improved modestly during calibration (NSE of 0.93, R2 of 0.95) compared to the original SWAT (NSE of 0.83, R2 of 0.93). Between 1980–2009, the number of stressful events, a moment in time where high or low flows occur simultaneously with stream temperatures exceeding 21 °C, increased by 55% and average streamflow increased by 60%. This study supports using the hydroclimatological SWAT component and provides an example method for assessing stressful conditions in southern New England’s coldwater habitats. Full article
Figures

Figure 1

Open AccessArticle Velocity Distribution and 3D Turbulence Characteristic Analysis for Flow over Water-Worked Rough Bed
Water 2017, 9(9), 668; doi:10.3390/w9090668
Received: 31 July 2017 / Revised: 31 August 2017 / Accepted: 1 September 2017 / Published: 8 September 2017
Cited by 1 | PDF Full-text (3517 KB) | HTML Full-text | XML Full-text
Abstract
To reproduce the natural flow topography in a laboratory environment, it is crucial to recapture its bed condition in order to ensure the accurate representation. Water-worked bed represents a state-of-the-art experimentally formed bed to imitate the natural-formed channel in most rivers or natural
[...] Read more.
To reproduce the natural flow topography in a laboratory environment, it is crucial to recapture its bed condition in order to ensure the accurate representation. Water-worked bed represents a state-of-the-art experimentally formed bed to imitate the natural-formed channel in most rivers or natural streams. Recently, this technique has been intensively studied through experimental and computational approaches; however, its actual influence towards the near-bed flow as compared to experimentally prepared rough bed in well-packed bedform order are still yet to be investigated deeply. This experimental study systematically investigated and compared the differences in velocity distribution and three-dimensional (3D) turbulence characteristics, including turbulence intensities and Reynolds stresses, between uniform smooth bed, laboratory-prepared rough bed and water-worked bed open channel flows. The flow comparisons were concentrated at near-bed region where clear flow behaviour change can be observed. Through these comparisons, the study inspected the characteristics of water-worked bedform thoroughly, in order to inform future experimental research that tries to reproduce natural stream behaviours. Full article
Figures

Figure 1

Open AccessArticle Debris Flow Susceptibility Assessment in the Wudongde Dam Area, China Based on Rock Engineering System and Fuzzy C-Means Algorithm
Water 2017, 9(9), 669; doi:10.3390/w9090669
Received: 29 March 2017 / Revised: 15 June 2017 / Accepted: 17 June 2017 / Published: 4 September 2017
PDF Full-text (5024 KB) | HTML Full-text | XML Full-text
Abstract
Debris flows in the Wudongde dam area, China could pose a huge threat to the running of the power station. Therefore, it is of great significance to carry out a susceptibility analysis for this area. This paper presents an application of the rock
[...] Read more.
Debris flows in the Wudongde dam area, China could pose a huge threat to the running of the power station. Therefore, it is of great significance to carry out a susceptibility analysis for this area. This paper presents an application of the rock engineering system and fuzzy C-means algorithm (RES_FCM) for debris flow susceptibility assessment. The watershed of the Jinsha River close to the Wudongde dam site in southwest China was taken as the study area, where a total of 22 channelized debris flow gullies were mapped by field investigations. Eight environmental parameters were selected for debris flow susceptibility assessment, namely, lithology, watershed area, slope angle, stream density, length of the main stream, curvature of the main stream, distance from fault and vegetation cover ratio. The interactions among these parameters and their weightings were determined using the RES method. A debris flow susceptibility map was produced by dividing the gullies into three categories of debris flow susceptibility based on the susceptibility index (SI) using the FCM algorithm. The results show that the susceptibility levels for nine of the debris flow gullies are high, nine are moderate and four are low, respectively. The RES based K-means algorithm (RES_KM) was used for comparison. The results suggest that the RES_FCM method and the RES_KM method provide very close evaluation results for most of the debris flow gullies, which also agree well with field investigations. The prediction accuracy of the new method is 90.9%, larger than that obtained by the RES_KM method (86.4%). Therefore, the RES_FCM method performs better than the RES_KM method for assessing the susceptibility of debris flows. Full article
(This article belongs to the Special Issue Hillslope and Watershed Hydrology)
Figures

Figure 1

Open AccessArticle Sulfide Precipitation in Wastewater at Short Timescales
Water 2017, 9(9), 670; doi:10.3390/w9090670
Received: 3 July 2017 / Revised: 28 August 2017 / Accepted: 1 September 2017 / Published: 5 September 2017
Cited by 1 | PDF Full-text (1056 KB) | HTML Full-text | XML Full-text
Abstract
Abatement of sulfides in sewer systems using iron salts is a widely used strategy. When dosing at the end of a pumping main, the reaction kinetics of sulfide precipitation becomes important. Traditionally the reaction has been assumed to be rapid or even instantaneous.
[...] Read more.
Abatement of sulfides in sewer systems using iron salts is a widely used strategy. When dosing at the end of a pumping main, the reaction kinetics of sulfide precipitation becomes important. Traditionally the reaction has been assumed to be rapid or even instantaneous. This work shows that this is not the case for sulfide precipitation by ferric iron. Instead, the reaction time was found to be on a timescale where it must be considered when performing end-of-pipe treatment. For real wastewaters at pH 7, a stoichiometric ratio around 14 mol Fe(II) (mol S(−II))−1 was obtained after 1.5 s, while the ratio dropped to about 5 mol Fe(II) (mol S(−II))−1 after 30 s. Equilibrium calculations yielded a theoretic ratio of 2 mol Fe(II) (mol S(−II))−1, indicating that the process had not equilibrated within the span of the experiment. Correspondingly, the highest sulfide conversion only reached 60%. These findings differed significantly from what has been demonstrated in previous studies and what is attained from theoretical equilibrium conditions. Full article
(This article belongs to the Special Issue Recent Advances in Water Management: Saving, Treatment and Reuse)
Figures

Figure 1

Open AccessArticle Experimental Research on an Improved Slope Protection Structure in the Plunge Pool of a High Dam
Water 2017, 9(9), 671; doi:10.3390/w9090671
Received: 24 July 2017 / Revised: 31 August 2017 / Accepted: 31 August 2017 / Published: 5 September 2017
PDF Full-text (11994 KB) | HTML Full-text | XML Full-text
Abstract
Due to impinging jets, the hydraulic load in a plunge pool can be very large and may cause serious damage to the slope and bottom protection structures. Conventional research mainly focuses on the stability of the plunge pool floor, and studies on slope
[...] Read more.
Due to impinging jets, the hydraulic load in a plunge pool can be very large and may cause serious damage to the slope and bottom protection structures. Conventional research mainly focuses on the stability of the plunge pool floor, and studies on slope protection safety are still lacking. Based on the Wudongde project, a physical model (that does not consider the plunge pool floor) was established. A series of experiments were conducted to investigate the protective measures for slope protection. Experimental results showed that the high seepage pressure on the back surface of the slope lining plate and poor correlation between the fluctuating pressures on both plate surfaces may cause large pressure differences that seriously threaten the stability of the slope lining plate. Therefore, a self-drainage slope protection structure was proposed to reduce the hydraulic load on a slope lining plate. It must be noted that the slope lining plate with the most violent water level fluctuation and adverse operating conditions (when the drainage system and part of the waterstops were invalid) were considered in the model tests. Test results indicated that self-drainage slope protection could enhance the synchronism of the pressure and water-level fluctuations on both plate surfaces. Therefore, the proposed slope protection structure could effectively reduce the total pressure on the plate and significantly increase the operational safety of the plunge pool. Full article
Figures

Figure 1

Open AccessArticle Phosphate Removal from Agricultural Tile Drainage with Iron Enhanced Sand
Water 2017, 9(9), 672; doi:10.3390/w9090672
Received: 14 July 2017 / Revised: 25 August 2017 / Accepted: 29 August 2017 / Published: 6 September 2017
PDF Full-text (3820 KB) | HTML Full-text | XML Full-text
Abstract
Can iron enhanced sand filtration capture total phosphorus and soluble phosphorus (phosphate) from agricultural tile drainage? A monitoring study measured the total phosphorus and phosphate capture performance of an iron enhanced sand filter (IESF) installed to treat agricultural tile drainage in Wright County,
[...] Read more.
Can iron enhanced sand filtration capture total phosphorus and soluble phosphorus (phosphate) from agricultural tile drainage? A monitoring study measured the total phosphorus and phosphate capture performance of an iron enhanced sand filter (IESF) installed to treat agricultural tile drainage in Wright County, MT, USA. Overall, for natural rainfall-induced tile drainage events monitored between June and November 2015 and again in 2016, the IESF captured 66% ± 7% (α = 0.05, n = 21) of the influent total phosphorus mass and 64% ± 8% (α = 0.05, n = 31) of the influent phosphate mass. Removal of total phosphorus and phosphate was approximately uniform for large and small rainfall-induced tile drainage events and varied from 42% to 95% for total phosphorus and 9% to 87% for phosphate. The IESF treated 290 m of treated depth since installation, and results indicate that performance is similar or better than constructed wetlands or other IESFs, though not as good as laboratory experiments of IESFs. Routine and non-routine maintenance was performed throughout the project to ensure adequate phosphorus capture and flow rate through the IESF. Full article
(This article belongs to the Special Issue Additives in Stormwater Filters for Enhanced Pollutant Removal)
Figures

Figure 1

Open AccessArticle Bivariate Return Period for Design Hyetograph and Relationship with T-Year Design Flood Peak
Water 2017, 9(9), 673; doi:10.3390/w9090673
Received: 13 July 2017 / Revised: 18 August 2017 / Accepted: 31 August 2017 / Published: 6 September 2017
PDF Full-text (3084 KB) | HTML Full-text | XML Full-text
Abstract
This study focuses on the return period evaluation for design hyetographs, which is usually estimated by adopting a univariate statistical approach. Joint Return Period (JRP) and copula-based multivariate analysis are used in this work to better define T-year synthetic rainfall patterns which can
[...] Read more.
This study focuses on the return period evaluation for design hyetographs, which is usually estimated by adopting a univariate statistical approach. Joint Return Period (JRP) and copula-based multivariate analysis are used in this work to better define T-year synthetic rainfall patterns which can be used as input for design flood peak estimation by means of hydrological simulation involving rainfall-runoff (RR) models. Specifically, a T-year Design Hyetograph (DH) is assumed to be characterized by its peak H, at the chosen time resolution Δt, and by the total rainfall height W, cumulated on its critical duration dCri, which has been a priori fixed. As stated in technical literature, the choice of the expression for JRP depends on which event is deemed as critical for the investigated system; the most important cases are: (i) all the variables must exceed a certain magnitude to achieve critical conditions; or (ii) at least one variable must be greater than a threshold; or (iii) critical conditions are induced by all the events with a joint Cumulative Density Function (CDF) overcoming an assigned probability threshold. Once the expression for JRP was chosen, the relationship among multivariate T-year design hyetographs and T-year design flood peak was investigated for a basin located in Calabria region (southern Italy). Specifically, for the selected case study, a summary diagram was obtained as final result, which allows the main characteristics of T-year DHs to be estimated, considering both the univariate and the copula based multivariate analysis, and the associated T-year design flood peaks obtained through the simulation with a RR model. Full article
Figures

Figure 1

Open AccessArticle Comparison of Potential Risk on Two Managed Aquifer Recharge Sites from River Basin
Water 2017, 9(9), 674; doi:10.3390/w9090674
Received: 26 June 2017 / Revised: 30 August 2017 / Accepted: 2 September 2017 / Published: 6 September 2017
PDF Full-text (6521 KB) | HTML Full-text | XML Full-text
Abstract
Drinking water production facilities are designed to filter contaminants that are ever-present in raw water. These facilities, however, pose risks of tap water contamination or water supply discontinuation in the event of a massive chemical spill. A managed aquifer recharge (MAR) offers the
[...] Read more.
Drinking water production facilities are designed to filter contaminants that are ever-present in raw water. These facilities, however, pose risks of tap water contamination or water supply discontinuation in the event of a massive chemical spill. A managed aquifer recharge (MAR) offers the advantage of purifying surface water as well as maintaining water underground for extended periods of time, thus securing sufficient time for a response to contaminant infiltration and dramatically increasing consumer safety. However, contaminated aquifers are difficult to recover; accordingly, it is important that MAR sites engage in preemptive responses to chemical spills in order to protect their aquifers. This study assesses potential risks in order to quantify the detrimental impacts of chemical spills in cities located in river basins on drinking water supply facilities. The targets of analysis are two MAR sites in South Korea. The potential risk analysis offers grounds upon which aggressive basin management can be implemented to ensure water supply facility operation safety. The lack of data for available for analysis is addressed using a stochastic methodology that ranks cities in which MAR sites are endangered based on the cities’ potential risk probability distributions. The results of the analysis show that water supply facilities surrounded by larger cities have relatively higher potential risks, and would, therefore, need to handle more management targets to prevent chemical spills. Furthermore, the proposed methodology contributes not only to potential risk management of existing water supply facilities, but also to MAR site selection. Full article
(This article belongs to the Special Issue New Advances in Integrated River Basin Management)
Figures

Figure 1

Open AccessArticle Refuge Lake Reclassification in 620 Minnesota Cisco Lakes under Future Climate Scenarios
Water 2017, 9(9), 675; doi:10.3390/w9090675
Received: 2 August 2017 / Revised: 1 September 2017 / Accepted: 4 September 2017 / Published: 7 September 2017
PDF Full-text (2825 KB) | HTML Full-text | XML Full-text
Abstract
Cisco (Coregonus artedi) is the most common coldwater stenothermal fish in Minnesota lakes. Water temperature (T) and dissolved oxygen (DO) in lakes are important controls of fish growth and reproduction and likely change with future climate warming. Built upon a previous
[...] Read more.
Cisco (Coregonus artedi) is the most common coldwater stenothermal fish in Minnesota lakes. Water temperature (T) and dissolved oxygen (DO) in lakes are important controls of fish growth and reproduction and likely change with future climate warming. Built upon a previous study, this study uses a modified method to identify which of 620 cisco lakes in Minnesota can still support cisco populations under future climate and therefore be classified as cisco refuge lakes. The previous study used oxythermal stress parameter TDO3, the temperature at DO of 3 mg/L, simulated only from deep virtual lakes to classify 620 cisco lakes. Using four categories of virtual but representative cisco lakes in modified method, a one-dimensional water quality model MINLAKE2012 was used to simulate daily T and DO profiles in 82 virtual lakes under the past (1961–2008) and two future climate scenarios. A multiyear average of 31-day largest TDO3 over variable benchmark (VB) periods, AvgATDO3VB, was calculated from simulated T and DO profiles using FishHabitat2013. Contour plots of AvgATDO3VB for four categories of virtual lakes were then developed to reclassify 620 cisco lakes into Tier 1 (AvgATDO3VB < 11 °C) or Tier 2 refuge lakes, and Tier 3 non-refuge lakes (AvgATDO3VB > 17 °C). About 20% of 620 cisco lakes are projected to be refuge lakes under future climate scenarios, which is a more accurate projection (improving the prediction accuracy by ~6.5% from the previous study) since AvgATDO3VB was found to vary by lake categories. Full article
(This article belongs to the Special Issue Water Quality Monitoring and Modeling in Lakes)
Figures

Figure 1

Open AccessArticle Laboratory Investigation of the Effect of Slenderness Effect on the Non-Darcy Groundwater Flow Characteristics in Bimsoils
Water 2017, 9(9), 676; doi:10.3390/w9090676
Received: 1 June 2017 / Revised: 2 September 2017 / Accepted: 5 September 2017 / Published: 7 September 2017
PDF Full-text (6962 KB) | HTML Full-text | XML Full-text
Abstract
A series of experimental flow tests for artificial block-in-matrix-soils (bimsoils) samples with various slenderness ratios were performed to study the Non-Darcy groundwater flow characteristics. The variations of seepage velocity, permeability coefficient, critical sample height, and non-Darcy flow factor for samples against slenderness ratios
[...] Read more.
A series of experimental flow tests for artificial block-in-matrix-soils (bimsoils) samples with various slenderness ratios were performed to study the Non-Darcy groundwater flow characteristics. The variations of seepage velocity, permeability coefficient, critical sample height, and non-Darcy flow factor for samples against slenderness ratios were investigated. A servo-controlled flow testing system that was developed by the authors was adopted to conduct the flow test. Cylindrical bimsoil samples (50 mm diameter and various heights) with staggered rock block percentages (RBPs) (30, 40, 50, and 60%, by mass) were prepared by compaction tests to roughly insure the same porosity of the soil matrix. The testing results show that flow the distance has a strong influence on the flow characteristics of bimsoil, and the relationship between the permeability coefficient and slenderness ratio is proposed. In addition, the critical sample height to eliminate the slenderness effect was determined, and the relationship between the critical sample height and RBP was established. Moreover, the responses of non-Darcy flow were studied by using an index of non-Darcy βfactor, which reveals the internal mechanism of the effect of flow distance on groundwater flow characteristics. The research results can be useful to the prediction of flow piping disaster for geological body made up of bimsoils. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Effects of Climate Change on Lake Thermal Structure and Biotic Response in Northern Wilderness Lakes
Water 2017, 9(9), 678; doi:10.3390/w9090678
Received: 2 August 2017 / Revised: 1 September 2017 / Accepted: 3 September 2017 / Published: 7 September 2017
PDF Full-text (5399 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Climate disrupts aquatic ecosystems directly through changes in temperature, wind, and precipitation, and indirectly through watershed effects. Climate-induced changes in northern lakes include longer ice-free season, stronger stratification, browning, shifts in algae, and more cyanobacterial blooms. We compared retrospective temperature-depth relationships modeled using
[...] Read more.
Climate disrupts aquatic ecosystems directly through changes in temperature, wind, and precipitation, and indirectly through watershed effects. Climate-induced changes in northern lakes include longer ice-free season, stronger stratification, browning, shifts in algae, and more cyanobacterial blooms. We compared retrospective temperature-depth relationships modeled using MINLAKE2012 with biogeochemical changes recorded in sediment cores. Four lakes in Voyageurs National Park (VOYA) and four lakes in Isle Royale National Park (ISRO) were studied. Meteorological data from International Falls and Duluth, Minnesota, were used for VOYA and ISRO, respectively. Model output was processed to analyze epilimnetic and hypolimnetic water temperatures and thermal gradients between two periods (1962–1986, 1987–2011). Common trends were increased summer epilimnion temperatures and, for deep lakes, increased frequency and duration of thermoclines. Changes in diatom communities differed between shallow and deep lakes and the parks. Based on changes in benthic and tychoplanktonic communities, shallow lake diatoms respond to temperature, mixing events, pH, and habitat. Changes in deep lakes are evident in the deep chlorophyll layer community of Cyclotella and Discostella species, mirroring modeled changes in thermocline depth and stability, and in Asterionella and Fragilaria species, reflecting the indirect effects of in-lake and watershed nutrient cycling and spring mixing. Full article
(This article belongs to the Special Issue Water Quality Monitoring and Modeling in Lakes)
Figures

Figure 1

Open AccessArticle Analysis of Changes in Spatio-Temporal Patterns of Drought across South Korea
Water 2017, 9(9), 679; doi:10.3390/w9090679
Received: 26 July 2017 / Revised: 4 September 2017 / Accepted: 6 September 2017 / Published: 7 September 2017
PDF Full-text (10960 KB) | HTML Full-text | XML Full-text
Abstract
Since the climatic features of South Korea are highly complex and time variable, spatio-temporal-based drought frequency analysis is a prerequisite for drought risk management. The spatial extent of drought risk analysis in a bivariate framework has scarcely been applied in South Korea before.
[...] Read more.
Since the climatic features of South Korea are highly complex and time variable, spatio-temporal-based drought frequency analysis is a prerequisite for drought risk management. The spatial extent of drought risk analysis in a bivariate framework has scarcely been applied in South Korea before. In this study, the spatio-temporal changes in drought events are investigated at 55 stations across South Korea during 1980–2015. A variety of probability distributions and copulas are applied, and the best fitted is selected on the basis the goodness of fit. The spatial distributions of primary and secondary return periods showed a high risk of drought due to the unusual precipitation pattern in the western coast areas and at Uljin station and a relative low risk of drought in the northwestern portion and surrounding areas of Yeongju, Uiseong, Boeun and Daejeon stations. Overall, the spatial distribution patterns of primary and secondary (Kendall) return periods are similar. However, their applicability changes according to the type of drought risk to be considered. The spatio-temporal quantification of the return period can be used for establishing the proper water demand and supply system and helps to overcome the challenges faced in the hydrometeorological regulations of reservoirs in the southwest coast. Full article
Figures

Figure 1

Open AccessArticle Climate Change Impacts on Sediment Quality of Subalpine Reservoirs: Implications on Management
Water 2017, 9(9), 680; doi:10.3390/w9090680
Received: 8 August 2017 / Revised: 4 September 2017 / Accepted: 5 September 2017 / Published: 7 September 2017
PDF Full-text (1249 KB) | HTML Full-text | XML Full-text
Abstract
Reservoirs are characterized by accumulation of sediments where micropollutants may concentrate, with potential toxic effects on downstream river ecosystems. However, sediment management such as flushing is needed to maintain storage capacity. Climate change is expected to increase sediment loads, but potential effects on
[...] Read more.
Reservoirs are characterized by accumulation of sediments where micropollutants may concentrate, with potential toxic effects on downstream river ecosystems. However, sediment management such as flushing is needed to maintain storage capacity. Climate change is expected to increase sediment loads, but potential effects on their quality are scarcely known. In this context, sediment contamination by trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and organics (Polycyclic Aromatic Hydrocarbons PAHs, Polychlorinated Biphenyls PCBs and C > 12 hydrocarbons) was analyzed in 20 reservoirs located in Italian Central Alps. A strong As and a moderate Cd, Hg and Pb enrichment was emphasized by Igeo, with potential ecotoxicological risk according to Probable Effect Concentration quotients. Sedimentation rate, granulometry, total organic carbon (TOC) and altitude resulted as the main drivers governing pollutant concentrations in sediments. According to climate change models, expected increase of rainfall erosivity will enhance soil erosion and consequently the sediment flow to reservoirs, potentially increasing coarse grain fractions and thus potentially diluting pollutants. Conversely, increased weathering may enhance metal fluxes to reservoirs. Increased vegetation cover will potentially result in higher TOC concentrations, which may contrast contaminant bioavailability and thus toxicity. Our results may provide elements for a proper management of contaminated sediments in a climate change scenario aiming at preserving water quality and ecosystem functioning. Full article
(This article belongs to the Special Issue Adaptation Strategies to Climate Change Impacts on Water Resources)
Figures

Open AccessArticle Pseudomonas aeruginosa Psl Exopolysaccharide Interacts with the Antimicrobial Peptide LG21
Water 2017, 9(9), 681; doi:10.3390/w9090681
Received: 9 June 2017 / Revised: 30 August 2017 / Accepted: 4 September 2017 / Published: 16 September 2017
PDF Full-text (3849 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Biofilm formation by opportunistic pathogens serves as one of the major causes of chronic and persistent infections. Bacterial cells in the biofilms are embedded in their self-generated protective extracellular polymeric substances (EPS), which include exopolysaccharides, large adhesin proteins and extracellular DNA. In this
[...] Read more.
Biofilm formation by opportunistic pathogens serves as one of the major causes of chronic and persistent infections. Bacterial cells in the biofilms are embedded in their self-generated protective extracellular polymeric substances (EPS), which include exopolysaccharides, large adhesin proteins and extracellular DNA. In this study, we identified an antimicrobial peptide (AMP) LG21 that is able to interact specifically with the Psl exopolysaccharide of Pseudomonas aeruginosa, thus it can be used as a diagnostic tool for P. aeruginosa biofilms. Molecular dynamics simulation analysis showed that residues numbered from 15 to 21 (WKRKRFG) in LG21 are involved in interacting with Psl. Our study indicates that host immune systems might detect and interact with microbial biofilms through AMPs. Engineering biofilm EPS-targeting AMPs might provide novel strategies for biofilm detection and treatment. Full article
(This article belongs to the Special Issue Antimicrobial Resistance in Environmental Waters)
Figures

Figure 1

Open AccessArticle Study on the Climate Adaption Planning for an Industrial Company with Regional Risk of the Water Supply System—A Case in Taiwan
Water 2017, 9(9), 682; doi:10.3390/w9090682
Received: 18 July 2017 / Revised: 1 September 2017 / Accepted: 1 September 2017 / Published: 8 September 2017
PDF Full-text (5656 KB) | HTML Full-text | XML Full-text
Abstract
Extreme uneven spatial and temporal distributions of rainfall pose the risk of water shortage to the industries in Taiwan, particularly during dry seasons, which may be worsen under climate change. This study aims to develop adaptation actions for an industrial company to reduce
[...] Read more.
Extreme uneven spatial and temporal distributions of rainfall pose the risk of water shortage to the industries in Taiwan, particularly during dry seasons, which may be worsen under climate change. This study aims to develop adaptation actions for an industrial company to reduce the risk of droughts. The Formosa Plastics Corporation (FPC) in Chuoshui River watershed is selected as a study case and an integrated risk assessment tool of water resources TaiWAP is used. The water shortage of FPC is mainly in the dry seasons because the water rights of public and agricultural uses are prioritized over industrial use. The considered adaptation options including water reuse, a desalination plant, smart agricultural water management, and rainwater harvesting. The results show that the waste-water reuse and sea-water desalination are the most effective adaptation options, which reduces the water shortage risks 33–44% per day in the return period of ten years. The results are generalized for the reference of other studies. The risk assessment and adaptation measure identification of the company require regional information. Moreover, some adaptation measures that the company implements help reduce the water shortage of the region and are consequently beneficial to the company, e.g., smart agricultural water management. Full article
Figures

Figure 1

Open AccessArticle Estimation of Sediment Yield Change in a Loess Plateau Basin, China
Water 2017, 9(9), 683; doi:10.3390/w9090683
Received: 19 July 2017 / Revised: 30 August 2017 / Accepted: 5 September 2017 / Published: 8 September 2017
PDF Full-text (9702 KB) | HTML Full-text | XML Full-text
Abstract
Soil erosion is one of the most serious land degradation problems and the primary environmental issue in the Loess Plateau region of China. To identify the critical sub-basins and assess the impacts of land use change and climatic variability change on soil loss,
[...] Read more.
Soil erosion is one of the most serious land degradation problems and the primary environmental issue in the Loess Plateau region of China. To identify the critical sub-basins and assess the impacts of land use change and climatic variability change on soil loss, this study tested the feasibility of the Soil and Water Assessment Tool (SWAT) model on sediment load simulation in the upper Sang-kan (USK) River basin. Based on a land use map of 1986, the SWAT model (Scenario 0) was calibrated at a monthly step using climate data from 1979 to 1985; then it was validated using climate data from 1986 to 1990. The monthly sediment simulation results indicated that the model did not work as well as streamflow simulation, indicating lower NS (Nash-Sutcliffe Efficiency) and r2 values of 0.68, 0.69 and 0.61, 0.59 for the calibration period and validation period, respectively. This model could perform well under relatively low rainfall events, but it underestimated or overestimated the sediment load under high rainfall events. Comparing the results of scenarios with different land use maps (year of 1986 vs. 2012) and climate periods (1979–1990 vs. 2001–2012), it can be concluded that: (i) extreme and severe erosion almost always happened in FRST (forest land) and RNGE (grassland) in the hilly area; (ii) long-term traditional farming weakens the soil anti-erosion capability of land, leading to higher soil erosion, while forest can improve the soil structure, enhance the soil anti-erosion capability, and reduce soil erosion; (iii) both land use change and climatic change have led to the sediment yield decrease in the USK basin. Acting as the major influencing factor, land use change contributed to about 64.9% of the sediment yield reduction in the USK river basin. Full article
(This article belongs to the Special Issue Soil Erosion by Water)
Figures

Figure 1

Open AccessArticle Assessment of Hydrologic Alterations in Elbe and Rhine Rivers, Germany
Water 2017, 9(9), 684; doi:10.3390/w9090684
Received: 2 August 2017 / Revised: 3 September 2017 / Accepted: 5 September 2017 / Published: 8 September 2017
PDF Full-text (6477 KB) | HTML Full-text | XML Full-text
Abstract
In light of recent anthropogenic-induced climate change, a burning question at present is how these changes influence the water regime of rivers, which are of vital importance for humans as well as for biota. In this study, we investigate the changes in the
[...] Read more.
In light of recent anthropogenic-induced climate change, a burning question at present is how these changes influence the water regime of rivers, which are of vital importance for humans as well as for biota. In this study, we investigate the changes in the hydrologic regime of two major German rivers, Elbe and Rhine, after the middle of the 20th century. Here, we use the widely adopted Range of Variability Approach (RVA) method on daily streamflow data from five (Elbe) and seven (Rhine) hydrological stations to determine the variability and spatial pattern of hydrologic alterations. We discuss the potential effect of climate change on the water regime of these two rivers, as well as other potential causes. For both rivers, we find that some hydrologic parameters are highly altered, especially the number of reversals, indicating higher variability. The highest impact is found at Ems hydrological station on Rhine River. The order of affected hydrological stations follows mostly the downstream course of both rivers. Our study indicates that the hydrological behavior of Elbe and Rhine Rivers has altered since the middle of the 20th century, a probable consequence of climate change. These hydrologic alterations can lead to undesirable ecological effects on local biota. Full article
Figures

Figure 1

Open AccessArticle Modelling Crop Pattern Changes and Water Resources Exploitation: A Case Study
Water 2017, 9(9), 685; doi:10.3390/w9090685
Received: 29 June 2017 / Revised: 31 August 2017 / Accepted: 6 September 2017 / Published: 8 September 2017
Cited by 2 | PDF Full-text (2473 KB) | HTML Full-text | XML Full-text
Abstract
Agriculture and farming worldwide are responsible for numerous environmental threats, including degradation of land and water resource depletion. Underlining the dynamic interaction between bio-physical and socio-economic drivers is the key towards a more sustainable land and water management. With regard to a highly-developed
[...] Read more.
Agriculture and farming worldwide are responsible for numerous environmental threats, including degradation of land and water resource depletion. Underlining the dynamic interaction between bio-physical and socio-economic drivers is the key towards a more sustainable land and water management. With regard to a highly-developed agricultural area in Southern Italy, multi-regression models were developed to provide an ex-post interpretation of the observed inter-annual variability of cropped land. The main drivers related to Common Agricultural Policy support, product market prices, crop yield, and irrigation water availability were investigated. The adopted models revealed the different weights of each driver. The findings reported the role that direct payments played in supporting the extension of irrigated crops, such as processing tomato. Likewise, the models pointed out the decoupled payment scheme as the most important driver of change in the crop pattern over the last years. Full article
(This article belongs to the Special Issue Water Economics and Policy)
Figures

Figure 1

Open AccessArticle Simulating Laboratory Braided Rivers with Bed-Load Sediment Transport
Water 2017, 9(9), 686; doi:10.3390/w9090686
Received: 12 June 2017 / Revised: 27 August 2017 / Accepted: 5 September 2017 / Published: 8 September 2017
PDF Full-text (12585 KB) | HTML Full-text | XML Full-text
Abstract
Numerical models provide considerable assistance in the investigation of complicated processes in natural rivers. In the present study, a physics-based two-dimensional model has been developed to simulate the braiding processes and morphodynamic changes in braided rivers. The model applies the basic hydrodynamic and
[...] Read more.
Numerical models provide considerable assistance in the investigation of complicated processes in natural rivers. In the present study, a physics-based two-dimensional model has been developed to simulate the braiding processes and morphodynamic changes in braided rivers. The model applies the basic hydrodynamic and sediment transport principles with bed morphology deformation and a TVD (Total Variation Diminishing) scheme to predict trans-critical flows and bed morphology deformation. The non-equilibrium transport process of graded bed load sediment is simulated, with non-uniform sediments, secondary flows, and sheltering effects being included. A multiple bed layer technique is adopted to represent the vertical sediment sorting process. The model has been applied to simulate the bed evolution process in an experimental river with bed load transport. Comparisons between the experimental river and predicted river are analysed, including their pattern evolution processes, important braiding phenomena, and statistical characteristics. Avulsion activities have been found in the braiding evolution process, representing the primary ways in which channels form and disappear in braided rivers. The increases in the active braiding intensity and total braiding intensity show similar trends to those observed in the experimental river. Statistical methods are applied to assess the scale-invariant topographic properties of the simulated river and real rivers. The model demonstrated its potential to predict the morphodynamics in natural rivers. Full article
Figures

Figure 1

Open AccessArticle Virtual Water Flows at the County Level in the Heihe River Basin, China
Water 2017, 9(9), 687; doi:10.3390/w9090687
Received: 29 June 2017 / Revised: 1 September 2017 / Accepted: 5 September 2017 / Published: 14 September 2017
PDF Full-text (2588 KB) | HTML Full-text | XML Full-text
Abstract
Water scarcity in arid regions can be addressed by using the virtual water concept in water resources management. This research used a compiled county-level input–output table to analyze virtual water flows for the Heihe River Basin in 2012 by applying a multi-regional input–output
[...] Read more.
Water scarcity in arid regions can be addressed by using the virtual water concept in water resources management. This research used a compiled county-level input–output table to analyze virtual water flows for the Heihe River Basin in 2012 by applying a multi-regional input–output (MRIO) model. The results showed that the Heihe River Basin is a net virtual water exporter at a scale of 1.05 billion m3, which accounts for one third of the total amount of the basin’s water resources. The midstream area of the basin imports 96.31% of virtual water (2.04 billion m3) and exports 88.84% of virtual water (0.94 billion m3). In contrast, the upstream and downstream parts have limited virtual water flows. The agricultural sector largely consumes water in each county; maize or wheat production accounts for approximately 50% of the total water consumption. For most sectors, the virtual water content from surface water is greater than that from groundwater. The ratio of virtual surface water to virtual groundwater ranges from 1.20 to 2.91. The results for the water stress index indicated that most counties experienced water stress due to maize production. Greater attention needs to be paid to the adaptation and assessment of virtual water strategies in arid regions. Full article
(This article belongs to the Special Issue Sustainable Water Management within Inland River Watershed)
Figures

Figure 1

Open AccessCommunication On the Influence of Input Data Quality to Flood Damage Estimation: The Performance of the INSYDE Model
Water 2017, 9(9), 688; doi:10.3390/w9090688
Received: 18 July 2017 / Revised: 21 August 2017 / Accepted: 5 September 2017 / Published: 8 September 2017
PDF Full-text (2605 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
IN-depth SYnthetic Model for Flood Damage Estimation (INSYDE) is a model for the estimation of flood damage to residential buildings at the micro-scale. This study investigates the sensitivity of INSYDE to the accuracy of input data. Starting from the knowledge of input parameters
[...] Read more.
IN-depth SYnthetic Model for Flood Damage Estimation (INSYDE) is a model for the estimation of flood damage to residential buildings at the micro-scale. This study investigates the sensitivity of INSYDE to the accuracy of input data. Starting from the knowledge of input parameters at the scale of individual buildings for a case study, the level of detail of input data is progressively downgraded until the condition in which a representative value is defined for all inputs at the census block scale. The analysis reveals that two conditions are required to limit the errors in damage estimation: the representativeness of representatives values with respect to micro-scale values and the local knowledge of the footprint area of the buildings, being the latter the main extensive variable adopted by INSYDE. Such a result allows for extending the usability of the model at the meso-scale, also in different countries, depending on the availability of aggregated building data. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Climate Change Adaptation in a Mediterranean Semi-Arid Catchment: Testing Managed Aquifer Recharge and Increased Surface Reservoir Capacity
Water 2017, 9(9), 689; doi:10.3390/w9090689
Received: 7 August 2017 / Revised: 30 August 2017 / Accepted: 5 September 2017 / Published: 8 September 2017
Cited by 2 | PDF Full-text (3103 KB) | HTML Full-text | XML Full-text
Abstract
Among different uses of freshwater, irrigation is the most impacting groundwater resource, leading to water table depletion and possible seawater intrusion. The unbalance between the availability of water resources and demand is currently exacerbated and could become worse in the near future in
[...] Read more.
Among different uses of freshwater, irrigation is the most impacting groundwater resource, leading to water table depletion and possible seawater intrusion. The unbalance between the availability of water resources and demand is currently exacerbated and could become worse in the near future in accordance with climate change observations and scenarios provided by Intergovernmental Panel on Climate Change (IPCC). In this context, Increasing Maximum Capacity of the surface reservoir (IMC) and Managed Aquifer Recharge (MAR) are adaptation measures that have the potential to enhance water supply systems resiliency. In this paper, a multiple-users and multiple-resources-Water Supply System (WSS) model is implemented to evaluate the effectiveness of these two adaptation strategies in a context of overexploited groundwater under the RCP 4.5 and the RCP 8.5 IPCC scenarios. The presented a case study that is located in the Puglia, a semi-arid region of South Italy characterized by a conspicuous water demand for irrigation. We observed that, although no significant long-term trend affects the proposed precipitation scenarios, the expected temperature increase highly impacts the WSS resources due to the associated increase of water demand for irrigation purposes. Under the RCP 4.5 the MAR scenario results are more effective than the IMC during long term wet periods (typically 5 years) and successfully compensates the impact on the groundwater resources. Differently, under RCP 8.5, due to more persistent dry periods, both adaptation scenarios fail and groundwater resource become exposed to massive sea water intrusion during the second half of the century. We conclude that the MAR scenario is a suitable adaptation strategy to face the expected future changes in climate, although mitigation actions to reduce green-house gases are strongly required. Full article
(This article belongs to the Special Issue Adaptation Strategies to Climate Change Impacts on Water Resources)
Figures

Figure 1

Open AccessFeature PaperCommunication Wheat Straw as a Bio-Sorbent for Arsenate, Chromate, Fluoride, and Nickel
Water 2017, 9(9), 690; doi:10.3390/w9090690
Received: 2 July 2017 / Revised: 5 September 2017 / Accepted: 7 September 2017 / Published: 9 September 2017
PDF Full-text (627 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Batch-type experiments were used to study As(V), Cr(VI), F, and Ni2+ sorption/desorption on wheat straw. For the lowest concentration added (0.5 mmol·L−1), the sorption sequence was F > Ni2+ > Cr(VI) >> As(V) (93%, 61%, 29%,
[...] Read more.
Batch-type experiments were used to study As(V), Cr(VI), F, and Ni2+ sorption/desorption on wheat straw. For the lowest concentration added (0.5 mmol·L−1), the sorption sequence was F > Ni2+ > Cr(VI) >> As(V) (93%, 61%, 29%, 0.3%), but changed to Ni2+ > F > Cr(VI) >> As(V) when 3.0 and 6.0 mmol·L−1 were added (with 65%, 54%, 25%, 0%, and 68%, 52%, 27%, 0% sorption, respectively). Overall, As(V) showed the lowest sorption, whereas it was 25–37% for Cr(VI), 61–68% for Ni2+, and 52–93% for F. For As(V), pH in the equilibrium solution was always above the pH of the point of zero charge (pHPZC) for wheat straw, decreasing sorption efficiency. For Cr(VI), pH was below pHPZC, but not enough to reach high sorption. For F, pH in the equilibrium was above pHPZC, which could reduce sorption. For Ni2+, pH in the equilibrium was always below pHPZC, which made sorption difficult. The satisfactory fitting of Cr(VI), F, and Ni2+ data to the Freundlich model suggests multilayer-type adsorption. Desorption was high for F, whereas Ni2+ showed the lowest desorption. This research could be especially relevant when focusing on the use of wheat straw as a bio-sorbent, and in cases where straw mulching is used. Full article
(This article belongs to the Special Issue Heavy Metals and Potentially Toxic Elements (PTEs) in Water)
Figures

Figure 1

Open AccessArticle Adapting the Relaxed Tanks-in-Series Model for Stormwater Wetland Water Quality Performance
Water 2017, 9(9), 691; doi:10.3390/w9090691
Received: 15 July 2017 / Revised: 18 August 2017 / Accepted: 4 September 2017 / Published: 9 September 2017
Cited by 1 | PDF Full-text (2414 KB) | HTML Full-text | XML Full-text
Abstract
Across the globe, water quality standards have been implemented to protect receiving waters from stormwater pollution, motivating regulators (and consequently designers) to develop tools to predict the performance of stormwater control measures such as constructed stormwater wetlands (CSWs). The goal of this study
[...] Read more.
Across the globe, water quality standards have been implemented to protect receiving waters from stormwater pollution, motivating regulators (and consequently designers) to develop tools to predict the performance of stormwater control measures such as constructed stormwater wetlands (CSWs). The goal of this study was to determine how well the relaxed tanks-in-series (P-k-C*) model described the performance of CSWs in North Carolina. Storm events monitored at 10 CSWs in North Carolina were used for calibrating the model, and statistical evaluations concluded the model could adequately predict the performance for all pollutants except organic nitrogen. Nash–Sutcliff calibration/validation values were determined to be 0.72/0.78, 0.78/0.74, 0.91/0.87, 0.72/0.62, 0.88/0.73, and 0.91/0.63 for total nitrogen, total ammoniacal nitrogen, oxidized nitrogen, organic nitrogen, total phosphorus, and total suspended solids, respectively. Sensitivity analysis revealed only one calibration parameter with strong sensitivity, the Arrhenius coefficient (temperature dependent model coefficient). With this model, CSWs can be optimized to treat watershed-specific influent concentrations to meet effluent targets. In general, the current design technique used in North Carolina and many other locations (a first flush volume detention method) oversizes CSWs for water quality vis-à-vis the method herein, suggesting improved designs for water quality may be possible through scientifically-informed methods. Full article
(This article belongs to the Special Issue Treatment Wetlands for Nutrient Removal)
Figures

Figure 1

Open AccessArticle Assessment of the Combined Effects of Threshold Selection and Parameter Estimation of Generalized Pareto Distribution with Applications to Flood Frequency Analysis
Water 2017, 9(9), 692; doi:10.3390/w9090692
Received: 29 July 2017 / Revised: 2 September 2017 / Accepted: 7 September 2017 / Published: 10 September 2017
PDF Full-text (1667 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Floods are costly natural disasters that are projected to increase in severity and frequency into the future. Exceedances over a high threshold and analysis of their distributions, as determined through the Peak Over Threshold (POT) method and approximated by a Generalized Pareto Distribution
[...] Read more.
Floods are costly natural disasters that are projected to increase in severity and frequency into the future. Exceedances over a high threshold and analysis of their distributions, as determined through the Peak Over Threshold (POT) method and approximated by a Generalized Pareto Distribution (GPD), respectively, are widely used for flood frequency analysis. This study investigates the combined effects of threshold selection and GPD parameter estimation on the accuracy of flood quantile estimates, and develops a new, widely-applicable framework that significantly improves the accuracy of flood quantile estimations. First, the performance of several parameter estimators (i.e., Maximum Likelihood; Probability Weighted Moments; Maximum Goodness of Fit; Likelihood Moment; Modified Likelihood Moment; and Nonlinear Weighted Least Square Error) for the GPD was compared through Monte Carlo simulation. Then, a calibrated Soil and Water Assessment Tool (SWAT) model for the province of Alberta, Canada, was used to reproduce daily streamflow series for 47 watersheds distributed across the province, and the POT was applied to each. The Goodness of Fit for the resulting flood frequency models was measured by the upper tail Anderson-Darling (AD) test and the root-mean-square error (RMSE) and demonstrated improvements for more than one-third of stations by averages of 65% (AD) and 47% (RMSE), respectively. Full article
Figures

Figure 1

Open AccessArticle Model and Growth Stage Based Variability of the Irrigation Demand of Onion Crops with Predicted Climate Change
Water 2017, 9(9), 693; doi:10.3390/w9090693
Received: 31 May 2017 / Revised: 6 September 2017 / Accepted: 7 September 2017 / Published: 11 September 2017
PDF Full-text (1418 KB) | HTML Full-text | XML Full-text
Abstract
Predicted climate change will affect agricultural water resources. Particularly vegetable crops will be concerned due to high water demand and high vulnerability to water scarcity. Present vegetable production already requires irrigation water. To assess future irrigation demand, the impact of climate change needs
[...] Read more.
Predicted climate change will affect agricultural water resources. Particularly vegetable crops will be concerned due to high water demand and high vulnerability to water scarcity. Present vegetable production already requires irrigation water. To assess future irrigation demand, the impact of climate change needs to be revealed region- and crop-specifically. For robust predictions, a wide range of scenarios has to be simulated using different climate models. The aim of this study is to identify the climate change impact on water availability, precipitation-free periods and irrigation demand of onion crops cultivated in a German model region. Focus is on crop-specific climatic water balance, considering soil characteristics and temperature-driven plant growth. Simulated climate parameters vary between four climate models. However, in all scenarios climate parameters indicate an increasing water demand until 2100. While amount of irrigation water will not increase tremendously, occurrence and duration of dry periods will require efficient irrigation infrastructure and management. Full article
Figures

Figure 1

Open AccessArticle Spatial and Seasonal Variation of Biomineral Suspended Particulate Matter Properties in High-Turbid Nearshore and Low-Turbid Offshore Zones
Water 2017, 9(9), 694; doi:10.3390/w9090694
Received: 3 August 2017 / Revised: 7 September 2017 / Accepted: 11 September 2017 / Published: 12 September 2017
PDF Full-text (3589 KB) | HTML Full-text | XML Full-text
Abstract
Suspended particulate matter (SPM) is abundant and essential in marine and coastal waters, and comprises a wide variety of biomineral particles, which are practically grouped into organic biomass and inorganic sediments. Such biomass and sediments interact with each other and build large biomineral
[...] Read more.
Suspended particulate matter (SPM) is abundant and essential in marine and coastal waters, and comprises a wide variety of biomineral particles, which are practically grouped into organic biomass and inorganic sediments. Such biomass and sediments interact with each other and build large biomineral aggregates via flocculation, therefore controlling the fate and transport of SPM in marine and coastal waters. Despite its importance, flocculation mediated by biomass-sediment interactions is not fully understood. Thus, the aim of this research was to explain biologically mediated flocculation and SPM dynamics in different locations and seasons in marine and coastal waters. Field measurement campaigns followed by physical and biochemical analyses had been carried out from 2004 to 2011 in the Belgian coastal area to investigate bio-mediated flocculation and SPM dynamics. Although SPM had the same mineralogical composition, it encountered different fates in the turbidity maximum zone (TMZ) and in the offshore zone (OSZ), regarding bio-mediated flocculation. SPM in the TMZ built sediment-enriched, dense, and settleable biomineral aggregates, whereas SPM in the OSZ composed biomass-enriched, less dense, and less settleable marine snow. Biological proliferation, such as an algal bloom, was also found to facilitate SPM in building biomass-enriched marine snow, even in the TMZ. In short, bio-mediated flocculation and SPM dynamics varied spatially and seasonally, owing to biomass-sediment interactions and bio-mediated flocculation. Full article
(This article belongs to the Special Issue Sediment Transport in Coastal Waters)
Figures

Figure 1

Open AccessArticle Evaluating the Drivers of Seasonal Streamflow in the U.S. Midwest
Water 2017, 9(9), 695; doi:10.3390/w9090695
Received: 3 August 2017 / Revised: 30 August 2017 / Accepted: 8 September 2017 / Published: 12 September 2017
PDF Full-text (4835 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Streamflows have increased notably across the U.S. Midwest over the past century, fueling a debate on the relative influences of changes in precipitation and land cover on the flow distribution. Here, we propose a simple modeling framework to evaluate the main drivers of
[...] Read more.
Streamflows have increased notably across the U.S. Midwest over the past century, fueling a debate on the relative influences of changes in precipitation and land cover on the flow distribution. Here, we propose a simple modeling framework to evaluate the main drivers of streamflow rates. Streamflow records from 290 long-term USGS stream gauges were modeled using five predictors: precipitation, antecedent wetness, temperature, agriculture, and population density. We evaluated which predictor combinations performed best for every site, season and streamflow quantile. The goodness-of-fit of our models is generally high and varies by season (higher in the spring and summer than in the fall and winter), by streamflow quantile (best for high flows in the spring and winter, best for low flows in the fall, and good for all flow quantiles in summer), and by region (better in the southeastern Midwest than in the northwestern Midwest). In terms of predictors, we find that precipitation variability is key for modeling high flows, while antecedent wetness is a crucial secondary driver for low and median flows. Temperature improves model fits considerably in areas and seasons with notable snowmelt or evapotranspiration. Finally, in agricultural and urban basins, harvested acreage and population density are important predictors of changing streamflow, and their influence varies seasonally. Thus, any projected changes in these drivers are likely to have notable effects on future streamflow distributions, with potential implications for basin water management, agriculture, and flood risk management. Full article
Figures

Figure 1

Open AccessArticle Implication of Directly Connected Impervious Areas to the Mitigation of Peak Flows in Urban Catchments
Water 2017, 9(9), 696; doi:10.3390/w9090696
Received: 18 July 2017 / Revised: 23 August 2017 / Accepted: 1 September 2017 / Published: 12 September 2017
PDF Full-text (9427 KB) | HTML Full-text | XML Full-text
Abstract
The existence of impervious areas is one of the most distinguishing characteristics of urban catchments. They decrease infiltration and increase direct runoff in urban catchments. The recent introduction of green infrastructure in urban catchments for the purpose of sustainable development has contributed to
[...] Read more.
The existence of impervious areas is one of the most distinguishing characteristics of urban catchments. They decrease infiltration and increase direct runoff in urban catchments. The recent introduction of green infrastructure in urban catchments for the purpose of sustainable development has contributed to the decrease in directly connected impervious areas (DCIA) by isolating existing impervious areas, and consequently, has also contributed to flood risk mitigation. This study coupled the width function-based instantaneous hydrograph (WFIUH), which is able to handle the spatial distribution of the impervious areas, with the concept of the DCIA to assess the impact of decreasing DCIA on the shape of direct runoff hydrographs. Using several scenarios for typical green infrastructure and the corresponding changes of DCIA for a test catchment in Seoul, South Korea, this study evaluated the effect of green infrastructure on the shape of the resulting direct runoff hydrographs and reducing peak flows. The results showed that the changes in the DCIA immediately affect the shape of the direct runoff hydrograph, and decrease peak flows by up to 12% depending on spatial implementation scenarios in the test catchment. This study demonstrates the importance of the DCIA concept for the evaluation of green infrastructures in urban catchments, enabling quantitative assessment of the spatial distribution of impervious areas, and also changes to the DCIA by various types of green infrastructure. The results of this study also suggest that more effective and well-planned green infrastructures could be introduced in urban environments for the purpose of flood risk management. Full article
Figures

Figure 1

Open AccessArticle Combined Coagulation and Ultrafiltration Process to Counteract Increasing NOM in Brown Surface Water
Water 2017, 9(9), 697; doi:10.3390/w9090697
Received: 14 August 2017 / Revised: 6 September 2017 / Accepted: 7 September 2017 / Published: 13 September 2017
PDF Full-text (11978 KB) | HTML Full-text | XML Full-text
Abstract
Membrane hybrid processes—coagulation coupled with ultrafiltration (UF)—have become a common method to comply with the legal, chemical, and microbiological requirements for drinking water. The main advantages of integrating coagulation with membrane filtration are the enhanced removal of natural organic matter (NOM) and reduced
[...] Read more.
Membrane hybrid processes—coagulation coupled with ultrafiltration (UF)—have become a common method to comply with the legal, chemical, and microbiological requirements for drinking water. The main advantages of integrating coagulation with membrane filtration are the enhanced removal of natural organic matter (NOM) and reduced membrane fouling. With in-line coagulation, coagulants are patched into the feed stream directly prior to the membrane process, without removing the coagulated solids. Compared with conventional coagulation/sedimentation, in-line coagulation/membrane reduces the treatment time and footprint. Coagulant dosing could be challenging in raw water of varying quality; however, with relatively stable specific ultraviolet absorbance (SUVA), dosing can be controlled. Recent studies indicate that UV absorbance correlates well with humic substances (HS), the major fraction to be removed during coagulation. This paper describes and evaluates a 30-month UF pilot trial on the surface water of Lake Neden (Sweden), providing drinking water to 60,000 residents. In this study, automatic coagulant dosing based on online measurement was successfully applied. Online sensor data were used to identify the current optimal aluminium coagulation conditions (0.5–0.7 mg L−1) and the potential boundaries (0.9–1.2 mg L−1) for efficient future (2040) NOM removal. The potential increase in NOM could affect the Al dose and drinking water quality significantly within 20 years, should the current trends in dissolved organic carbon (DOC) prevail. UV absorbance, the freshness index, and liquid chromatography-organic carbon detection (LC-OCD) measurements were used to optimise the process. Careful cross-calibration of raw and filtered samples is recommended when using online sensor data for process optimisation, even in low-turbidity water (formazin nephelometric unit (FNU) < 5). Full article
Figures

Figure 1

Open AccessFeature PaperArticle Incorporating the Vadose Zone into the Budyko Framework
Water 2017, 9(9), 698; doi:10.3390/w9090698
Received: 27 June 2017 / Revised: 15 August 2017 / Accepted: 30 August 2017 / Published: 13 September 2017
PDF Full-text (231 KB) | HTML Full-text | XML Full-text
Abstract
The Budyko framework provides a quantitative description of long-term average annual evapotranspiration at catchment scales in terms of macro-climatic variables. This framework, however, makes no reference to the vadose zone because it neglects changes in ubsurface storage in the catchment water balance. Recent
[...] Read more.
The Budyko framework provides a quantitative description of long-term average annual evapotranspiration at catchment scales in terms of macro-climatic variables. This framework, however, makes no reference to the vadose zone because it neglects changes in ubsurface storage in the catchment water balance. Recent studies have shown clearly that vadose-zone water storage cannot be neglected at sub-catchment or sub-annual space and time scales, resulting in numerous model attempts to extend the original Budyko framework to incorporate the full water balance equation. Here we apply the approach taken in a companion paper on the original Budyko framework to show that it can be generalized rigorously to include changes in vadose-zone water storage in a manner that is both parsimonious in hypotheses and broad in scope. Full article
(This article belongs to the Special Issue Water and Solute Transport in Vadose Zone)
Open AccessArticle Applications of Mobile Augmented Reality to Water Resources Management
Water 2017, 9(9), 699; doi:10.3390/w9090699
Received: 23 June 2017 / Revised: 19 August 2017 / Accepted: 6 September 2017 / Published: 13 September 2017
PDF Full-text (4477 KB) | HTML Full-text | XML Full-text
Abstract
The present paper proposes a mobile prototype platform, based on Augmented Reality and multimedia smart-phone technology, which operates on a combination of real environment and computer-generated data in order to increase the human perception of a scene in real time. By enhancing visible
[...] Read more.
The present paper proposes a mobile prototype platform, based on Augmented Reality and multimedia smart-phone technology, which operates on a combination of real environment and computer-generated data in order to increase the human perception of a scene in real time. By enhancing visible details and displaying invisible or inexistent objects, this platform could improve water monitoring activities as well as the understanding of physical processes by technical and non-technical mobile workforces. At the same time, such a tool might support decision-makers in choosing strategies and actions aimed at forecasting, preventing, and mitigating environmental risks. A preliminary validation of the prototype performance was carried out in the field of water management, specifically for sample basin of Southern Italy. During the testing phase, this innovative application showed its ability to speed up field surveys, easily move around in unknown or remote places, and allow the employment of less-specialised users. These results could help reduce the time and costs of water monitoring activities, which would be perceived as essential by local administrators, contributing thus to the safeguard and the correct use of water resources. Full article
Figures

Figure 1

Open AccessArticle Effects on Infiltration and Evaporation When Adding Rapeseed-Oil Residue or Wheat Straw to a Loam Soil
Water 2017, 9(9), 700; doi:10.3390/w9090700
Received: 11 July 2017 / Revised: 8 September 2017 / Accepted: 11 September 2017 / Published: 14 September 2017
PDF Full-text (1001 KB) | HTML Full-text | XML Full-text
Abstract
The application of additives (e.g., wheat straw (WS) or rapeseed-oil residue (RR)) to soils is a common agronomic practice, used for improving soil water retention. Through a laboratory investigation, this study examined the effects of RR and WS on infiltration, evaporation, water distribution,
[...] Read more.
The application of additives (e.g., wheat straw (WS) or rapeseed-oil residue (RR)) to soils is a common agronomic practice, used for improving soil water retention. Through a laboratory investigation, this study examined the effects of RR and WS on infiltration, evaporation, water distribution, and water retention. The results indicated that the migration rate of the wetting front, as well as the accumulative infiltration and evaporation, decreased with the amount of applied additives. RR was more effective than WS for infiltration and evaporation suppression. Furthermore, in the Kostiakov model, the value of a decreased with an increasing amount of additive, becoming smaller than the corresponding control treatment (CK) value; by contrast, the value of n decreased with increasing amount of applied additive, remaining larger than the CK value. In the Rose model, the values of A for the soils mixed with additives were smaller than those of the CK, and decreased with increasing amount of additive. Moreover, compared with the CK, the maximum water content for the RR-applied soils increased by 17.84% after infiltration and by 47.66% after evaporation. In addition, the water retention coefficients (calculated as the soil moisture after evaporation divided by that after infiltration) for soils mixed with RR were the highest, indicating that RR is more effective than WS for improving the water retention of the soil layer. Full article
(This article belongs to the Special Issue Water and Solute Transport in Vadose Zone)
Figures

Figure 1

Open AccessArticle The Current Status and Future of Central Asia’s Fish and Fisheries: Confronting a Wicked Problem
Water 2017, 9(9), 701; doi:10.3390/w9090701
Received: 16 August 2017 / Revised: 8 September 2017 / Accepted: 11 September 2017 / Published: 14 September 2017
PDF Full-text (2025 KB) | HTML Full-text | XML Full-text
Abstract
Central Asia’s arid lowland ecosystems are dependent on water that originates in nearby mountains and is carried by rivers to terminal lakes and freshwater seas with no outlets to the ocean. Fish traditionally thrived in these waterways, but they have become increasingly jeopardized
[...] Read more.
Central Asia’s arid lowland ecosystems are dependent on water that originates in nearby mountains and is carried by rivers to terminal lakes and freshwater seas with no outlets to the ocean. Fish traditionally thrived in these waterways, but they have become increasingly jeopardized by water impoundment and diversion for energy and crop production. Fish capture in the five new Central Asian republics consequently entered a period of long decline, a trend that was accelerated by removal of the centralized controls imposed by the former Soviet Union. Production levels have recovered during the past decade, but only in some countries. A similar trend is evident with aquaculture, which reached its lowest production levels in 2003–2008 but now is partially recovering. In both cases, progress is most evident in water-deficient Uzbekistan. Fish capture in Kazakhstan’s Ili River ecosystem, including Kapchagay Reservoir and Lake Balkhash, is now dropping precipitously. Effects on the lake’s fisheries have been magnified by the disproportionate rates of disappearance of valuable carp and pike-perch. The interrelationships between water, energy, and food underlie these threats to Central Asia’s fish and define a classic “wicked problem” that must be addressed regionally with explicit attention given to fish as important components of the ecosystem. Recent developments, although not all positive, give reason for cautious optimism that the region’s fisheries and aquaculture industries can be stabilized. Full article
(This article belongs to the Special Issue The Future of Water Management in Central Asia)
Figures

Figure 1

Open AccessArticle Factors Affecting Tufa Degradation in Jiuzhaigou National Nature Reserve, Sichuan, China
Water 2017, 9(9), 702; doi:10.3390/w9090702
Received: 21 July 2017 / Revised: 31 August 2017 / Accepted: 12 September 2017 / Published: 14 September 2017
PDF Full-text (27738 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Water and tufa samples were collected from Arrow Bamboo Lake, the stream from Panda Lake to Five-Color Lake, Pearl Shoal and Shuzheng Lakes in Jiuzhaigou National Nature Reserve, China, between October 2013 and September 2014, to investigate tufa growth rate and water environment
[...] Read more.
Water and tufa samples were collected from Arrow Bamboo Lake, the stream from Panda Lake to Five-Color Lake, Pearl Shoal and Shuzheng Lakes in Jiuzhaigou National Nature Reserve, China, between October 2013 and September 2014, to investigate tufa growth rate and water environment (water temperature, pH, electric conductivity, major ions and nutrients), and analyzed to explore the main causes of tufa degradation. The mean annual rate of tufa growth was low and varied within lakes, with the maximum deposit thickness of 332 μm/y. The calcite saturation index ranged from 0.65 to 0.83. Scanning electron microscope images showed that the tufa deposits had non-isopachous structures, and diatoms were the dominant microorganisms that participated in tufa deposition. Porous and crystalline structures of deposits were linked with a high tufa growth and small amounts of diatoms. Conversely, tufa deposits with amorphous and loose structures showed a low crystal growth rate and a high number of diatoms. A one-way analysis of variance and a least significant difference test were applied to identify site differences in water chemistry. Linear correlations indicated that nitrate, phosphate and sulfate inhibit tufa growth (p < 0.05). Increased nitrogen and phosphorus concentrations that originate mainly from atmospheric pollution and tourist activities at scenic attractions could trigger excessive diatom growth, which inhibits tufa precipitation. A series of measures should be implemented (e.g., the visitor number and vehicles should be regulated and controlled) to minimize tufa degradation in the Jiuzhaigou National Nature Reserve. Full article
Figures

Figure 1

Open AccessArticle A New Approach to Quantify Shallow Water Hydrologic Exchanges in a Large Regulated River Reach
Water 2017, 9(9), 703; doi:10.3390/w9090703
Received: 10 May 2017 / Revised: 7 September 2017 / Accepted: 11 September 2017 / Published: 15 September 2017
PDF Full-text (9690 KB) | HTML Full-text | XML Full-text
Abstract
Hydrologic exchange is a crucial component of the water cycle. The strength of the exchange directly affects the biogeochemical and ecological processes that occur in the hyporheic zone and aquifer from micro to reach scales. Hydrologic exchange fluxes (HEFs) can be quantified using
[...] Read more.
Hydrologic exchange is a crucial component of the water cycle. The strength of the exchange directly affects the biogeochemical and ecological processes that occur in the hyporheic zone and aquifer from micro to reach scales. Hydrologic exchange fluxes (HEFs) can be quantified using many field measurement approaches, however, in a relatively large river (scale > 103 m), these approaches are limited by site accessibility, the difficulty of performing representative sampling, and the complexity of geomorphologic features and subsurface properties. In rivers regulated by hydroelectric dams, quantifying HEF rates becomes more challenging because of frequent hydropeaking events, featuring hourly to daily variations in flow and river stages created by dam operations. In this study, we developed and validated a new approach based on field measurements to estimate shallow water HEF rates across the river bed along the shoreline of the Columbia River, USA. Vertical thermal profiles measured by self-recording thermistors were combined with time series of hydraulic gradients derived from river stages and inland water levels to estimate the HEF rates. The results suggest that the HEF rates had high spatial and temporal heterogeneities over the riverbed, with predicted flux rates varied from +1 × 10−6 m s−1 to −1.5 × 10−6 m s−1 under different flow conditions. Full article
Figures

Figure 1

Open AccessArticle Optimization of a Water Quality Monitoring Network Using a Spatially Referenced Water Quality Model and a Genetic Algorithm
Water 2017, 9(9), 704; doi:10.3390/w9090704
Received: 14 June 2017 / Revised: 25 August 2017 / Accepted: 12 September 2017 / Published: 15 September 2017
PDF Full-text (1459 KB) | HTML Full-text | XML Full-text
Abstract
The monitoring network for a river system is designed to provide information about water quantity and quality. The development of Watershed Protection Plans and Total Maximum Daily Loads require systematic monitoring of waterbodies. In this study, optimum water quality monitoring networks were selected
[...] Read more.
The monitoring network for a river system is designed to provide information about water quantity and quality. The development of Watershed Protection Plans and Total Maximum Daily Loads require systematic monitoring of waterbodies. In this study, optimum water quality monitoring networks were selected to assess E. coli loads in the Guadalupe River and San Antonio River basins. A Genetic Algorithm (GA) was applied to select monitoring stations using the mean annual E. coli flux from the Spatially Referenced Regression Model on Watershed Attributes (SPARROW). The objectives of the GA were to minimize the number of monitoring stations, include large values of the mean annual E. coli flux, and minimize uncertainty of the flux estimations. Constraints related to the monitoring of critical locations were included in a multi-objective optimization problem. The SPARROW model was applied to the optimized GA solution sets, which were compared using the objective values and statistical indices. The best GA-generated alternative set adequately represented the San Antonio River basin, in good agreement with a previous study conducted using only SPARROW. The application of the GA ensured the inclusion of the monitoring stations with large values of E. coli flux, which reflected high-risk areas within the watershed. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Flood Inundation Modelling of Flash Floods in Steep River Basins and Catchments
Water 2017, 9(9), 705; doi:10.3390/w9090705
Received: 31 July 2017 / Revised: 4 September 2017 / Accepted: 12 September 2017 / Published: 15 September 2017
PDF Full-text (3685 KB) | HTML Full-text | XML Full-text
Abstract
The potential flood inundation extent can be estimated with flood inundation models, which can differ in the level of physical and numerical modelling complexity included in the solution procedure. In recent years, several studies have highlighted the benefits of shock-capturing flood inundation models,
[...] Read more.
The potential flood inundation extent can be estimated with flood inundation models, which can differ in the level of physical and numerical modelling complexity included in the solution procedure. In recent years, several studies have highlighted the benefits of shock-capturing flood inundation models, particularly when modelling a high Froude number or supercritical flows, or in areas prone to the occurrence of rapidly varying flood events, such as flash floods. Nonetheless, decision makers are often reluctant to implement more complex modelling tools into practical flood inundation modelling studies, unless evidence is provided to establish when such refined modelling tools should be used. The main objective of this study was to determine a general threshold value of the bottom slope that could be used by decision makers as an orientation guide to ascertain when to use a specific type of flood inundation model. The results obtained suggest that in torrential river basins or catchments (i.e., river basins and catchments with a bed slope generally greater than 1%), the flood inundation modelling should be conducted by using a flood inundation model that include shock-capturing algorithms in the model solution procedure. Full article
Figures

Figure 1

Open AccessArticle Local- and Plot-Scale Measurements of Soil Moisture: Time and Spatially Resolved Field Techniques in Plain, Hill and Mountain Sites
Water 2017, 9(9), 706; doi:10.3390/w9090706
Received: 2 June 2017 / Revised: 8 September 2017 / Accepted: 11 September 2017 / Published: 15 September 2017
PDF Full-text (12756 KB) | HTML Full-text | XML Full-text
Abstract
Soil moisture measurement is essential to validate hydrological models and satellite data. In this work we provide an overview of different local and plot scale soil moisture measurement techniques applied in three different conditions in terms of altitude, land use, and soil type,
[...] Read more.
Soil moisture measurement is essential to validate hydrological models and satellite data. In this work we provide an overview of different local and plot scale soil moisture measurement techniques applied in three different conditions in terms of altitude, land use, and soil type, namely a plain, a mountain meadow and a hilly vineyard. The main goal is to provide a synoptic view of techniques supported by practical case studies to show that in such different conditions it is possible to estimate a time and spatially resolved soil moisture by the same combination of instruments: contact-based methods (i.e., Time Domain Reflectometry—TDR, and two low frequency probes) for the time resolved, and hydro-geophysical minimally-invasive methods (i.e., Electromagnetic Induction—EMI, Ground Penetrating Radar—GPR, and the Electrical Resistivity Tomography—ERT) for the spatially resolved. Both long-term soil moisture measurements and spatially resolved measurement campaigns are discussed. Technical and operational measures are detailed to allow critical factors to be identified. Full article
(This article belongs to the Special Issue Advances in Hydro-Meteorological Monitoring)
Figures

Figure 1

Open AccessArticle Exploring the Spatial-Seasonal Dynamics of Water Quality, Submerged Aquatic Plants and Their Influencing Factors in Different Areas of a Lake
Water 2017, 9(9), 707; doi:10.3390/w9090707
Received: 5 June 2017 / Revised: 24 August 2017 / Accepted: 13 September 2017 / Published: 15 September 2017
PDF Full-text (2639 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The degradation of water quality in lakes and its negative effects on freshwater ecosystems have become a serious problem worldwide. Exploring the dynamics in the associated factors is essential for water pollution management and control. GIS interpolation, principal component analysis (PCA) and multivariate
[...] Read more.
The degradation of water quality in lakes and its negative effects on freshwater ecosystems have become a serious problem worldwide. Exploring the dynamics in the associated factors is essential for water pollution management and control. GIS interpolation, principal component analysis (PCA) and multivariate statistical techniques were used to identify the main pollution sources in different areas of Honghu Lake. The results indicate that the spatial distribution of the concentrations of total nitrogen (TN), total phosphate (TP), ammonia nitrogen (NH4+–N), and permanganate index (CODMn) have similar characteristics and that their values gradually increased from south to north during the three seasons in Honghu Lake. The major influencing factors of water quality varied across the different areas and seasons. The relatively high concentrations of TN and TP, which might limit the growth of submerged aquatic plants, were mainly caused by anthropogenic factors. Our work suggests that spatial analyses combined with PCA are useful for investigating the factors that influence water quality and submerged aquatic plant biomass in different areas of a lake. These findings provide sound information for the future water quality management of the lake or even the entire lake basin. Full article
(This article belongs to the Special Issue Water Quality Monitoring and Modeling in Lakes)
Figures

Open AccessArticle A Novel Calendar-Based Method for Visualizing Water Quality Change: The Case of the Yangtze River 2006–2015
Water 2017, 9(9), 708; doi:10.3390/w9090708
Received: 17 August 2017 / Revised: 10 September 2017 / Accepted: 13 September 2017 / Published: 15 September 2017
Cited by 1 | PDF Full-text (11905 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Mapping water quality change is helpful in the study of the water environment of a region. Using visual methods, interpretation of water condition and pollution issues can be intuitive and easy to understand. In this paper, we present a map to represent the
[...] Read more.
Mapping water quality change is helpful in the study of the water environment of a region. Using visual methods, interpretation of water condition and pollution issues can be intuitive and easy to understand. In this paper, we present a map to represent the spatial and temporal variation of water quality change in the Yangtze River during the period from 2006 to 2015. The calendar view was developed to explore the water quality condition and water pollutants for sections of the Yangtze River. A “W” construction was proposed to arrange the weekly water quality data in a continuous logic, and qualitative colors were designed to identify the change in major pollutants throughout the period. This map provides a promising visual analytical approach to investigate the water quality status and reveal the spatial and temporal patterns of water quality change in the Yangtze River. Full article
Figures

Figure 1

Open AccessArticle Assessing the Uncertainty of Multiple Input Datasets in the Prediction of Water Resource Components
Water 2017, 9(9), 709; doi:10.3390/w9090709
Received: 27 July 2017 / Revised: 4 September 2017 / Accepted: 7 September 2017 / Published: 16 September 2017
Cited by 2 | PDF Full-text (3667 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A large number of local and global databases for soil, land use, crops, and climate are now available from different sources, which often differ, even when addressing the same spatial and temporal resolutions. As the correct database is unknown, their impact on estimating
[...] Read more.
A large number of local and global databases for soil, land use, crops, and climate are now available from different sources, which often differ, even when addressing the same spatial and temporal resolutions. As the correct database is unknown, their impact on estimating water resource components (WRC) has mostly been ignored. Here, we study the uncertainty stemming from the use of multiple databases and their impacts on WRC estimates such as blue water and soil water for the Karkheh River Basin (KRB) in Iran. Four climate databases and two land use maps were used to build multiple configurations of the KRB model using the soil and water assessment tool (SWAT), which were similarly calibrated against monthly river discharges. We classified the configurations based on their calibration performances and estimated WRC for each one. The results showed significant differences in WRC estimates, even in models of the same class i.e., with similar performance after calibration. We concluded that a non-negligible level of uncertainty stems from the availability of different sources of input data. As the use of any one database among several produces questionable outputs, it is prudent for modelers to pay more attention to the selection of input data. Full article
Figures

Figure 1

Open AccessArticle Ranking of Storm Water Harvesting Sites Using Heuristic and Non-Heuristic Weighing Approaches
Water 2017, 9(9), 710; doi:10.3390/w9090710
Received: 31 July 2017 / Revised: 30 August 2017 / Accepted: 12 September 2017 / Published: 16 September 2017
PDF Full-text (940 KB) | HTML Full-text | XML Full-text
Abstract
Conservation of water is essential as climate change coupled with land use changes influence the distribution of water availability. Stormwater harvesting (SWH) is a widely used conservation measure, which reduces pressure on fresh water resources. However, determining the availability of stormwater and identifying
[...] Read more.
Conservation of water is essential as climate change coupled with land use changes influence the distribution of water availability. Stormwater harvesting (SWH) is a widely used conservation measure, which reduces pressure on fresh water resources. However, determining the availability of stormwater and identifying the suitable sites for SWH require consideration of various socio-economic and technical factors. Earlier studies use demand, ratio of runoff to demand and weighted demand distance, as the screening criteria. In this study, a Geographic Information System (GIS) based screening methodology is adopted for identifying potential suitable SWH sites in urban areas as a first pass, and then a detailed study is done by applying suitability criteria. Initially, potential hotspots are identified by a concept of accumulated catchments and later the sites are screened and ranked using various screening parameters namely demand, ratio of runoff to demand and weighted demand distance. During this process, the opinion of experts for finalizing the suitable SWH sites brings subjectivity in the methodology. To obviate this, heuristic (Saaty Analytic hierarchy process (AHP)) and non-heuristic approaches (Entropy weight, and Principal Component Analysis (PCA) weighing techniques) are adapted for allotting weights to the parameters and applied in the ranking of SWH sites in Melbourne, Australia and Dehradun, India. It is observed that heuristic approach is not effective for the study area as it was affected by the subjectivity in the expert opinion. Results obtained by non-heuristic approach come out to be in a good agreement with the sites finalized for SWH by the water planners of the study area. Hence, the proposed ranking methodology has the potential for application in decision making of suitable storm water harvesting sites. Full article
(This article belongs to the Special Issue Sponge Cities: Emerging Approaches, Challenges and Opportunities)
Figures

Figure 1

Open AccessArticle Variability of Stable Isotope in Lake Water and Its Hydrological Processes Identification in Mt. Yulong Region
Water 2017, 9(9), 711; doi:10.3390/w9090711
Received: 13 July 2017 / Revised: 11 September 2017 / Accepted: 12 September 2017 / Published: 16 September 2017
PDF Full-text (2440 KB) | HTML Full-text | XML Full-text
Abstract
Lakes are regarded as important nodes in water resources, playing pivotal roles in the regional hydrological cycle. However, the systematic study on lake water balance is scarce in Mt. Yulong region. Here, we study the stable isotope compositions of precipitation, inflowing rivers and
[...] Read more.
Lakes are regarded as important nodes in water resources, playing pivotal roles in the regional hydrological cycle. However, the systematic study on lake water balance is scarce in Mt. Yulong region. Here, we study the stable isotope compositions of precipitation, inflowing rivers and lake water to exploit the characteristics of hydrological supply and lake water balance. The results showed that there was a typical spatial distribution of surface isotope in August and April. Relatively high δ18O values with low d-excess were found on the east and west shores of the lake in August and in the middle part of the lake in April. The lowest δ18O with highest d-excess were found in the north and south shores in August and April, respectively. Meanwhile, slight isotopic stratification indicated that the lake water was vertically mixed-well. Subsequently, the evaporation-to-inflow ratios (E/Is) during the two periods were further derived based on the isotope mass balance model. Approximately 51% in August and 12% in April of the water flowing into Lashi Lake underwent evaporation. This study provides a reference for the long-term monitoring and modeling the hydrology processes of the basin, and is important for the regional water resource. Full article
(This article belongs to the Special Issue Isotopes in Hydrology and Hydrogeology)
Figures

Figure 1

Open AccessArticle Incorporating Rainfall-Runoff Events into Nitrate-Nitrogen and Phosphorus Load Assessments for Small Tile-Drained Catchments
Water 2017, 9(9), 712; doi:10.3390/w9090712
Received: 2 June 2017 / Revised: 1 September 2017 / Accepted: 13 September 2017 / Published: 16 September 2017
PDF Full-text (5110 KB) | HTML Full-text | XML Full-text
Abstract
Rainfall-runoff events significantly influence water runoff and the loss of pollutants from tile-drained agricultural land. We monitored ten small (4 to 38 ha) tile-drained catchments in Czechia for three to five years (2012 to 2016). The discharge was measured continuously; a regular 14-day
[...] Read more.
Rainfall-runoff events significantly influence water runoff and the loss of pollutants from tile-drained agricultural land. We monitored ten small (4 to 38 ha) tile-drained catchments in Czechia for three to five years (2012 to 2016). The discharge was measured continuously; a regular 14-day scheme of water quality monitoring was accompanied with event sampling provided by automatic samplers in 20 to 120 min intervals. A new semi-automated algorithm was developed for the identification of runoff events (RE) based on discharge and water temperature changes. We then quantified the share of RE on the total runoff and the N and P losses, and we compared six methods for nutrient load estimation on an annual and monthly basis. The results showed considerable differences among the monitored sites, seasons, and applied methods. The share of RE on N loads was on average 5% to 30% of the total annual load, whereas for P (dissolved and total), the share of RE was on average 10% to 80% on the total annual load. The most precise method for nutrient load estimation included the RE. The methods based on point monitoring of the discharge and water quality underestimated the loads of N by 10% to 20% and of P by 30% to 80%. The acquired findings are crucial for the improvement of nutrient load assessment in tile-drained catchments, as well as for the design of various mitigation measures on tile-drained agricultural land. Full article
Figures

Figure 1

Open AccessArticle Changes in Phytoplankton and Water Quality during Sustainable Restoration of an Urban Lake Used for Recreation and Water Supply
Water 2017, 9(9), 713; doi:10.3390/w9090713
Received: 19 May 2017 / Revised: 8 September 2017 / Accepted: 11 September 2017 / Published: 18 September 2017
PDF Full-text (3746 KB) | HTML Full-text | XML Full-text
Abstract
Groundwater intake near Lake Głębokie, situated in the city of Szczecin in Northwestern Poland, resulted in a distinct decrease in the lake water level. Water intake from a river and a neighboring urban area led to eutrophication and a strong cyanobacterial water bloom.
[...] Read more.
Groundwater intake near Lake Głębokie, situated in the city of Szczecin in Northwestern Poland, resulted in a distinct decrease in the lake water level. Water intake from a river and a neighboring urban area led to eutrophication and a strong cyanobacterial water bloom. Both the water intake and recreation were threatened due to the possible influence of cyanobacterial toxins. The lake was subjected to three sustainable restoration methods: aeration of sediment-water; iron addition to precipitate P, and; biomanipulation. The goal of our study was to determine the changes in the taxonomic composition of phytoplankton and chemical water variables during restoration measures. A comparison of the data obtained during this research with the pre-restoration data showed that, as a result of the treatments orthophosphates decreased, rarely exceeding 0.06 mg P·L−1, and cyanobacterial water blooms disappeared. Cyanobacteria were found in the lake but they were not abundant. Chrysophytes and diatoms were the most abundant in springtime of each year. Green algae, desmids and chrysophytes were particularly abundant in summer, while cryptophytes predominated in autumn. Algae from all these groups do not pose a threat to either recreation or water intake. The deep chlorophyll maximum occurring in summer at a depth of 5 m as a result of restoration confirms the lower trophic status of the lake, alluding to mesotrophic conditions. Full article
Figures