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Water, Volume 9, Issue 12 (December 2017)

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Editorial

Jump to: Research, Review, Other

Open AccessEditorial Recent Advances in Modelling and Implementation of Rainwater Harvesting Systems towards Sustainable Development
Water 2017, 9(12), 959; doi:10.3390/w9120959
Received: 9 October 2017 / Revised: 27 November 2017 / Accepted: 6 December 2017 / Published: 8 December 2017
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Abstract
Rainwater harvesting (RWH) is perhaps the most ancient practice to meet water supply needs. It has received renewed attention since the 1970s as a productive water source, water savings and conservation means, and sustainable development tool. In RWH, it is important to know
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Rainwater harvesting (RWH) is perhaps the most ancient practice to meet water supply needs. It has received renewed attention since the 1970s as a productive water source, water savings and conservation means, and sustainable development tool. In RWH, it is important to know how much water can be harvested at a given location from a given catchment size, whether the harvested water meets the intended water quality, whether the RWH system is economically viable and whether the state regulations favor the RWH. Furthermore, the selected RWH system should be suitable to local rainfall and field conditions, downstream impacts, and socio-economic and cultural characteristics. In this regard, this paper provides an overview of the special issue on “Rainwater Harvesting: Quantity, Quality, Economics and State Regulations”. The selected papers cover a wide range of issues that are relevant to RWH such as regionalization of design curves, use of spatial technology, urban agriculture, arid-region water supply, multi criteria analysis and application of artificial neural networks. Full article

Research

Jump to: Editorial, Review, Other

Open AccessArticle Delineating the Drainage Structure and Sources of Groundwater Flux for Lake Basaka, Central Rift Valley Region of Ethiopia
Water 2017, 9(12), 797; doi:10.3390/w9120797
Received: 15 September 2017 / Revised: 30 September 2017 / Accepted: 10 October 2017 / Published: 29 November 2017
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Abstract
As opposed to most of the other closed basin type rift valley lakes in Ethiopia, Lake Basaka is found to be expanding at an alarming rate. Different studies indicated that the expansion of the lake is challenging the socio-economics and environment of the
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As opposed to most of the other closed basin type rift valley lakes in Ethiopia, Lake Basaka is found to be expanding at an alarming rate. Different studies indicated that the expansion of the lake is challenging the socio-economics and environment of the region significantly. This study result and previous reports indicated that the lake’s expansion is mostly due to the increased groundwater (GW) flux to the lake. GW flux accounts for about 56% of the total inflow in recent periods (post 2000) and is found to be the dominant factor for the hydrodynamics and existence of the lake. The analysis of the drainage network for the area indicates the existence of a huge recharge area on the western and upstream side of the catchment. This catchment has no surface outlet; hence most of the incoming surface runoff recharges the GW system. The recharge area is the main source of GW flux to the lake. In addition to this, the likely sources/causes of GW flux to the lake could be: (i) an increase of GW recharge following the establishment of irrigation schemes in the region; (ii) subsurface inflow from far away due to rift system influence, and (iii) lake neotectonism. Overall, the lake’s expansion has damaging effect to the region, owing to its poor water quality; hence the identification of the real causes of GW flux and mitigation measures are very important for sustainable lake management. Therefore a comprehensive and detailed investigation of the parameters related to GW flux and the interaction of the lake with the GW system of the area is highly recommended. Full article
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Open AccessArticle Building Blocks: A Quantitative Approach for Evaluating Coastal Vulnerability
Water 2017, 9(12), 905; doi:10.3390/w9120905
Received: 23 August 2017 / Revised: 28 October 2017 / Accepted: 6 November 2017 / Published: 25 November 2017
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Abstract
Climate change and associated factors such as global and regional sea-level rise; the upsurge in high-intensity flooding events; and coastal erosion are pulse and press disturbances that threaten to increase landslides in coastal regions. Under these circumstances; a rigorous framework is required to
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Climate change and associated factors such as global and regional sea-level rise; the upsurge in high-intensity flooding events; and coastal erosion are pulse and press disturbances that threaten to increase landslides in coastal regions. Under these circumstances; a rigorous framework is required to evaluate coastal vulnerability in order to plan for future climate change scenarios. A vast majority of coastal vulnerability assessments across the globe are evaluated at the macro level (city scale) but not at the micro level (small town scale); particularly in the United Kingdom (UK). In order to fill this vital research gap; the current study established a coastal vulnerability index termed here as the Micro Town Coastal Vulnerability Index (MTCVI) and then applied it to Barton-on-Sea; which is a small coastal town of the Hampshire region; England; UK. MTCVI was evaluated for Barton-on-Sea coastal vulnerability by integrating both novel and existing parameters. Results suggest that the entire shoreline frontage (2 km) exhibits very high coastal vulnerability and is prone to various coastal hazards such as landslides; erosion; and wave intrusion. This suggests that Barton-on-Sea coastal amenities will require a substantial improvement in shoreline protection measures. In this study; GIS (geographic information system) coastal vulnerability and landslide maps were generated; and these maps can be used by the local authorities; district councils; coastal engineers; and planners to improve and design coastal management strategies under the climate change scenarios. Meanwhile; the methodology used in this study could also be applied to any other suitable location in the world depending on the availability of the data. Full article
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Open AccessArticle Physical Experiment and Numerical Simulation of the Artificial Recharge Effect on Groundwater Reservoir
Water 2017, 9(12), 908; doi:10.3390/w9120908
Received: 4 October 2017 / Revised: 17 November 2017 / Accepted: 20 November 2017 / Published: 23 November 2017
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Abstract
To improve the efficiency of utilizing water resources in arid areas, the mechanism of artificial recharge effecting on groundwater reservoir was analyzed in this research. Based on a generalized groundwater reservoir in a two-dimensional sand tank model, different scenarios of the infiltration basin
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To improve the efficiency of utilizing water resources in arid areas, the mechanism of artificial recharge effecting on groundwater reservoir was analyzed in this research. Based on a generalized groundwater reservoir in a two-dimensional sand tank model, different scenarios of the infiltration basin location and recharge intensity are designed to study how to improve the efficiency of groundwater reservoir artificial recharge. The effective storage capacity and the effective storage rate are taken as the main parameters to analyze the relation between recharge water volume and storage capacity. By combining with groundwater flow system theory, FEFLOW (Finite Element subsurface FLOW system) is adopted to set up the groundwater numerical model. It is used to verify the experiment results and to make deep analysis on the rule of water table fluctuations and groundwater movement in the aquifer. Based on the model, different scenarios are designed to examine the combined effect of recharge intensity and intermittent periods. The research results show that: the distance between infiltration basin and pumping well should be shortened appropriately, but not too close; increasing recharge intensity helps to enlarge the effective storage capacity, but it can also reduce the effective storage rate, which goes against the purpose of effective utilization of water resources; and, the recharge intensity and recharge duration should be given full consideration by the actual requirements when we take the approach of intermittent recharge to make a reasonable choice. Full article
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Open AccessArticle Unraveling the Long-Term Effects of Cr(VI) on the Performance and Microbial Community of Nitrifying Activated Sludge System
Water 2017, 9(12), 909; doi:10.3390/w9120909
Received: 30 October 2017 / Revised: 20 November 2017 / Accepted: 21 November 2017 / Published: 23 November 2017
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Abstract
The long-term effects of different influent Cr(VI) concentrations (0–0.5 mg L−1) on the nitrification activities and microbial community structures of nitrifying activated sludge system were investigated in this study. Results showed that the performance of ammonia oxidation was significantly inhibited, and
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The long-term effects of different influent Cr(VI) concentrations (0–0.5 mg L−1) on the nitrification activities and microbial community structures of nitrifying activated sludge system were investigated in this study. Results showed that the performance of ammonia oxidation was significantly inhibited, and the effluent concentration of ammonia nitrogen (NH4+-N) increased markedly when the influent Cr(VI) loading was equal or greater than 0.2 mg L−1. The specific oxygen utilization rate (SOUR), specific ammonium oxidation rate (SAOR), and specific nitrite oxidation rate (SNOR) of the system decreased from 53.24, 6.31, and 7.33 mg N g−1 VSS h−1 to 18.17, 1.68, and 2.88 mg N g−1 VSS h−1, respectively, with an increase of Cr(VI) concentration from 0 to 0.5 mg L−1. The protein/polysaccharide (PN/PS) ratio increased with the increasing Cr(VI) concentration, indicating that excessive PN secreted by microorganisms was conducive to resisting the toxicity of Cr(VI). High-throughput sequencing revealed that the relative abundance of ammonia-oxidizing bacteria (Nitrospira) and nitrite-oxidizing bacteria (Nitrosomonas and Nitrosospira) all decreased with the increasing Cr(VI) concentration, and ammonia-oxidizing bacteria were more sensitive to heavy metal toxicity than nitrite-oxidizing bacteria. The activities of nitrifying activated sludge system could not be completely recovered after a 30-d recovery process. Full article
(This article belongs to the Special Issue Heavy Metals and Potentially Toxic Elements (PTEs) in Water)
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Open AccessFeature PaperArticle Evolution of Uranium Isotopic Compositions of the Groundwater and Rock in a Sandy-Clayey Aquifer
Water 2017, 9(12), 910; doi:10.3390/w9120910
Received: 4 October 2017 / Revised: 3 November 2017 / Accepted: 20 November 2017 / Published: 23 November 2017
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Abstract
Uranium isotopes have been used as mechanistic or time scale tracers of natural processes. This paper describes the occurrence and redistribution of U in the Vendian aquifer of a paleo-valley in NW Russia. Forty-four rock samples were collected from nine boreholes with depths
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Uranium isotopes have been used as mechanistic or time scale tracers of natural processes. This paper describes the occurrence and redistribution of U in the Vendian aquifer of a paleo-valley in NW Russia. Forty-four rock samples were collected from nine boreholes with depths up to 160 m, and 25 groundwater samples were collected from 23 boreholes with depths up to 300 m. The U, Fe concentration, and 234U/238U activity ratio were determined in the samples. Estimations were made of the 14C and 234U-238U residence time of groundwater in the aquifer. It has been established that the processes of chemical weathering of Vendian deposits led to the formation of a strong oxidation zone, developed above 250 m.b.s.l. The inverse correlation between the concentrations of uranium and iron is a result of removal of U from paleo-valley slopes in oxidizing conditions, accumulation of U at the bottom of the paleo-valley in reducing conditions, and accumulation of Fe on the slopes and removal from the bottom of the paleo-valley. Almost all U on the slopes has been replaced by a newly formed hydrogenic U with a higher 234U/238U activity ratio. After, dissolution and desorption of hydrogenic U occurred from the slopes during periods with no glaciations and marine transgressions. Elevated concentrations of U are preserved in reduced lenses at the paleo-valley bottom. In these areas, the most dangerous aspect is the flow of groundwater from the underlying horizons, since during the operation of water supply wells it can lead to the creation of local zones of oxidizing conditions in the perforated screens zone and the transition of uranium into solution. For groundwater under oxidizing conditions, an increase in the concentration of uranium is characteristic of an increase in the residence time (age) of water in the aquifer. Also, the 234U/238U activity ratio increases with increasing radioactivity of groundwater. Therefore, the most rational approach is to use groundwater for drinking water supply from the slopes of the Northern Dvina basin. Full article
(This article belongs to the Special Issue Isotopes in Hydrology and Hydrogeology)
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Open AccessArticle Optimal Allocation Method of Irrigation Water from River and Lake by Considering the Field Water Cycle Process
Water 2017, 9(12), 911; doi:10.3390/w9120911
Received: 29 September 2017 / Revised: 20 November 2017 / Accepted: 20 November 2017 / Published: 23 November 2017
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Abstract
At present, the shortage of water resources has become a serious constraint to the further development of social economy. The optimal allocation of multi-water resources is valuable for agricultural water management in arid and semi-arid regions. However, traditional deterministic programming does not solve
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At present, the shortage of water resources has become a serious constraint to the further development of social economy. The optimal allocation of multi-water resources is valuable for agricultural water management in arid and semi-arid regions. However, traditional deterministic programming does not solve the complex water resources allocation in irrigation systems. Furthermore, previous allocation methods of irrigation water seldom considered the water cycle process, especially for multi-sources of irrigation. In this study, we develop an inexact fuzzy stochastic simulation-optimization programming (IFSSOP) model for the irrigation water optimal allocation of two water sources. The model combines the crop water model and the field water cycle model with an uncertainty optimization model, which considers the contribution of groundwater to crop water consumption. As a case study, the developed model is used in an arid area with two irrigation water sources: a river and a lake. Accordingly, the total optimal allocation irrigation water amounts of river and lake water under different violation probabilities in various hydrological years were obtained. By comparing the IFSSOP model with the IFSSOP model without considering the contribution of shallow groundwater (IFSSOP-NG model), it can be shown that the system benefits of the developed model are higher. With the lake water source from flood water, the region can save 30–34% of the river water, maintaining the original crop water deficit irrigation ratio. Consequently, application of the IFSSOP model in irrigation scheduling will provide effective water allocation patterns to save more water in an arid region with shallow groundwater. Full article
(This article belongs to the Special Issue Advances in Agriculture Water Efficiency)
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Open AccessArticle The Source, Flow Rates, and Hydrochemical Evolution of Groundwater in an Alluvial Fan of Qilian Mountain, Northwest China
Water 2017, 9(12), 912; doi:10.3390/w9120912
Received: 31 October 2017 / Revised: 19 November 2017 / Accepted: 21 November 2017 / Published: 23 November 2017
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Abstract
Major ions and selected environmental tracers (D, 18O, 3H and chlorofluorocarbons (CFCs)) were employed to determine the source, flow rates, and hydrochemical evolution of groundwater in an alluvial fan along the front of the Qilian Mountains, which serves as an important
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Major ions and selected environmental tracers (D, 18O, 3H and chlorofluorocarbons (CFCs)) were employed to determine the source, flow rates, and hydrochemical evolution of groundwater in an alluvial fan along the front of the Qilian Mountains, which serves as an important groundwater reservoir in northwest China. Temporal and spatial variations in ion concentrations were limited near the upper portion of the alluvial fan. However, groundwater quality deteriorated along the flow path as concentrations of Mg2+, Na+, SO42−, and Cl increased toward the fan toe and into the center of the valley. The relative abundance of the major cations and anions also changed down-fan from Ca2+ to Na+ and Mg2+, and from HCO3 to SO42− and Cl, respectively. Isotopic data suggests that precipitation within the Qilian Mountains, which recharged the alluvial deposits near the mountain front, was the primary source of groundwater. Apparent groundwater ages determined by CFCs varied from 23 to 40 years, and in general, increased in age from south to north (down-fan). It is concluded that groundwater in the study area was recharged by the Qilian Mountains, flowed through the alluvial fan from south to north, and was subsequently discharged several decades later from springs located along the toe of the fan, after which it re-entered the Shule River. Full article
(This article belongs to the Special Issue Isotopes in Hydrology and Hydrogeology)
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Open AccessArticle In Situ and Satellite Observation of CDOM and Chlorophyll-a Dynamics in Small Water Surface Reservoirs in the Brazilian Semiarid Region
Water 2017, 9(12), 913; doi:10.3390/w9120913
Received: 17 October 2017 / Revised: 12 November 2017 / Accepted: 20 November 2017 / Published: 4 December 2017
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Abstract
We analyzed chlorophyll-a and Colored Dissolved Organic Matter (CDOM) dynamics from field measurements and assessed the potential of multispectral satellite data for retrieving water-quality parameters in three small surface reservoirs in the Brazilian semiarid region. More specifically, this work is comprised of: (i)
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We analyzed chlorophyll-a and Colored Dissolved Organic Matter (CDOM) dynamics from field measurements and assessed the potential of multispectral satellite data for retrieving water-quality parameters in three small surface reservoirs in the Brazilian semiarid region. More specifically, this work is comprised of: (i) analysis of Chl-a and trophic dynamics; (ii) characterization of CDOM; (iii) estimation of Chl-a and CDOM from OLI/Landsat-8 and RapidEye imagery. The monitoring lasted 20 months within a multi-year drought, which contributed to water-quality deterioration. Chl-a and trophic state analysis showed a highly eutrophic status for the perennial reservoir during the entire study period, while the non-perennial reservoirs ranged from oligotrophic to eutrophic, with changes associated with the first events of the rainy season. CDOM characterization suggests that the perennial reservoir is mostly influenced by autochthonous sources, while allochthonous sources dominate the non-perennial ones. Spectral-group classification assigned the perennial reservoir as a CDOM-moderate and highly eutrophic reservoir, whereas the non-perennial ones were assigned as CDOM-rich and oligotrophic-dystrophic reservoirs. The remote sensing initiative was partially successful: the Chl-a was best modelled using RapidEye for the perennial one; whereas CDOM performed best with Landsat-8 for non-perennial reservoirs. This investigation showed potential for retrieving water quality parameters in dry areas with small reservoirs. Full article
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Open AccessArticle An Assessment of Ice Effects on Indices for Hydrological Alteration in Flow Regimes
Water 2017, 9(12), 914; doi:10.3390/w9120914
Received: 31 October 2017 / Revised: 18 November 2017 / Accepted: 21 November 2017 / Published: 23 November 2017
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Abstract
Preserving hydrological variability is important when developing environmental flow regimes, and a number of tools have been developed to support this process. A commonly applied method is the index of hydrological alteration (IHA), which describes a set of indices that can be used
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Preserving hydrological variability is important when developing environmental flow regimes, and a number of tools have been developed to support this process. A commonly applied method is the index of hydrological alteration (IHA), which describes a set of indices that can be used to assess changes in flow regimes. In cold climate regions, river ice can have large effects on flow regimes through frazil and anchor ice formation, ice cover formation, and ice break-up, and the impact of this is usually not included in the commonly used indexes. However, to understand the effect of ice formation and the break-up on the flow regime, the ice effects on the hydrology should be considered when assessing winter alteration indexes. This paper looks at the effects of river ice on winter flow conditions using data from Norwegian rivers, and discusses these effects in relation to hydrological variability. This paper also shows how indexes can be used to classify ice-induced variability, how this should be used to avoid ice-induced effects in the current analysis, and how this can be combined with the current indices to improve the winter flow regime classification. The findings from this paper show that frazil- and anchor-induced raises of the water level have a large impact on the perceived flow in winter, producing higher flow and deeper water than what the open water conditions discharge could do. Corresponding to this, winter lows connected to ice-induced high flows at other locations are also common. Finally, issues related to the assessment of the temporal and spatial effects of ice formation are discussed. Full article
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Open AccessArticle 200 kHz Sonication of Mixed-Algae Suspension from a Eutrophic Lake: The Effect on the Caution vs. Outbreak Bloom Alert Levels
Water 2017, 9(12), 915; doi:10.3390/w9120915
Received: 23 October 2017 / Revised: 20 November 2017 / Accepted: 22 November 2017 / Published: 24 November 2017
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Abstract
For effective ultrasonic algae removal, several studies have considered the ultrasound equipment linked factors, such as power and frequency. However, studies on the response of mixed algal cultures and associated water quality parameters to ultrasound are limited. In this lab-scale sonication, the removal
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For effective ultrasonic algae removal, several studies have considered the ultrasound equipment linked factors, such as power and frequency. However, studies on the response of mixed algal cultures and associated water quality parameters to ultrasound are limited. In this lab-scale sonication, the removal of cyanobacteria at a pre-set frequency of 200 kHz on mixed algae suspensions collected from a eutrophic lake was investigated. The caution (17.5 µg/L) and outbreak (1450 µg/L) alert levels in terms of chlorophyll-a (Chl-a) concentrations of the initial samples were each sonicated for 10, 15, and 20 min, and then kept in an incubator. Fifteen minutes of sonication resulted in best removal efficiency of 0.94 and 0.77, at an ultrasonic dose of 30 kWh/m3 at the outbreak and caution level concentrations, respectively. Immediately after 15 min sonication, and after standing in the incubator for a day, chlorophyll-a removal efficiencies of 0.28 and 0.90 were achieved in the outbreak level, respectively, and the matching removal efficiencies for the caution level were 0.23 and 0.64. Even though the removal was substantial in both cases, the final 147 µg/L chlorophyll-a concentration of the outbreak, which is itself still in the outbreak level range, shows that ultrasonication is not effective to satisfactorily remove algae from a concentrated suspension. Total dissolved nitrogen and chemical oxygen demand were reduced, overall, due to sonication. However, total dissolved phosphorus of the concentrated level was increased during the treatment. Although sonication needs further replicated experimental testing in whole-lake systems, our results show that 200 kHz sonication was able to reduce chlorophyll-a concentrations in small-scale laboratory tests. Full article
(This article belongs to the Special Issue Eutrophication of Waterways: An Old Problem with Modern Consequences)
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Open AccessFeature PaperArticle Water Saving and Cost Analysis of Large-Scale Implementation of Domestic Rain Water Harvesting in Minor Mediterranean Islands
Water 2017, 9(12), 916; doi:10.3390/w9120916
Received: 20 October 2017 / Revised: 16 November 2017 / Accepted: 22 November 2017 / Published: 25 November 2017
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Abstract
This paper describes a novel methodology to evaluate the benefits of large-scale installation of domestic Rain Water Harvesting (RWH) systems in multi-story buildings. The methodology was specifically developed for application to small settlements of the minor Mediterranean islands characterized by sharp fluctuations in
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This paper describes a novel methodology to evaluate the benefits of large-scale installation of domestic Rain Water Harvesting (RWH) systems in multi-story buildings. The methodology was specifically developed for application to small settlements of the minor Mediterranean islands characterized by sharp fluctuations in precipitation and water demands between winter and summer periods. The methodology is based on the combined use of regressive models for water saving evaluation and of geospatial analysis tools for semi-automatic collection of spatial information at the building/household level. An application to the old town of Lipari (Aeolian islands) showed potential for high yearly water savings (between 30% and 50%), with return on investment in less than 15 years for about 50% of the installed RWH systems. Full article
(This article belongs to the Special Issue Development of Alternative Water Sources in the Urban Sector)
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Open AccessArticle Propagation of Solitary Waves over Double Submerged Barriers
Water 2017, 9(12), 917; doi:10.3390/w9120917
Received: 23 October 2017 / Revised: 22 November 2017 / Accepted: 24 November 2017 / Published: 26 November 2017
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Abstract
Protection of nearshore area by means of artificial structure is an important issue for coastal engineering community. In this study, we aim to investigate wave hydrodynamics and hydrodynamic performance due to solitary waves interacting with double submerged barriers. Double barriers, put bottom-mounted vertically
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Protection of nearshore area by means of artificial structure is an important issue for coastal engineering community. In this study, we aim to investigate wave hydrodynamics and hydrodynamic performance due to solitary waves interacting with double submerged barriers. Double barriers, put bottom-mounted vertically on the flat seafloor and also paralleled to each other, are considered as a wave absorber. New experiments are carried out to provide measured data for model validation. Numerical simulations are performed using a depth- and phase-resolving model, based on the Reynolds-Averaged Navier–Stokes equations with a non-linear k-ɛ turbulence closure model. Model–data comparisons show good agreements in terms of free surface fluctuations in time histories and error analyses are performed. Numerical results are then used to study the variations of the free surface motions of breaking waves and the flow fields. In particular, the model results reveal that the optimal horizontal distance, judged as minimum wave transmission, between two submerged barriers is approximately 2.5 times the still water depth for present wave conditions and obstacle geometries. Furthermore, numerical model is extended to evaluate the functional efficiency of a dual-slotted-barrier system with different obstacle configurations under various conditions of solitary waves by means of energy reflection, transmission and dissipation coefficients. Full article
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Open AccessArticle Comparison of the Results from Microscopic Tests Concerning the Quality of Activated Sludge and Effluent
Water 2017, 9(12), 918; doi:10.3390/w9120918
Received: 30 September 2017 / Revised: 20 November 2017 / Accepted: 23 November 2017 / Published: 26 November 2017
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Abstract
Physicochemical studies on wastewater quality and microscopic analyses of activated sludge are necessary to properly evaluate the condition of activated sludge. The aim of this study was to evaluate the application of the sludge biotic index to determine when a change in treatment
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Physicochemical studies on wastewater quality and microscopic analyses of activated sludge are necessary to properly evaluate the condition of activated sludge. The aim of this study was to evaluate the application of the sludge biotic index to determine when a change in treatment quality is short-lived, caused by, e.g., a change in influent quality or quantity, and when it indicates adverse changes in the biocenosis of activated sludge, which would very likely result in the lower efficiency of wastewater treatment in the near future. The objects of the study were two identical parallel running small wastewater treatment plants. The following indicators of contamination were analyzed: the chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and total suspended solids (TSS). The authors additionally carried out a microscopic analysis. The study confirmed a correlation between the sludge biotic index and the removal efficiency of COD and BOD5; however, no correlation was found between the sludge biotic index and the removal efficiency of total suspended solids. The presence of metazoan microorganisms coincided in time with a good effluent treatment efficiency. When their quantity declined, a decrease in the efficiency of wastewater treatment was also observed. Full article
(This article belongs to the Special Issue Biological Treatment of Wastewater)
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Open AccessFeature PaperArticle Potential Impact on Freshwater Resources from Agrofuel Feedstock Cultivation in Thailand: Implications of the Alternative Energy Development Plan 2015
Water 2017, 9(12), 919; doi:10.3390/w9120919
Received: 18 October 2017 / Revised: 22 November 2017 / Accepted: 24 November 2017 / Published: 26 November 2017
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Abstract
The impact of water use in areas with abundant freshwater resources should not be the same as areas with limited resources. This impact is quantified as water scarcity footprint. The monthly water stress index with reference to environmental water requirement is proposed as
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The impact of water use in areas with abundant freshwater resources should not be the same as areas with limited resources. This impact is quantified as water scarcity footprint. The monthly water stress index with reference to environmental water requirement is proposed as a characterization factor. The biofuel policies of Thailand—cassava and sugarcane for bioethanol, and oil palm for biodiesel—were selected for the assessment based on land expansion and displacement scenarios. Cultivation was found to be the most water intensive phase in producing both biodiesel and bioethanol. Thus, the proposed index was applied for assessing and selecting areas having low values of the water scarcity footprint. The results showed low values for expanding oil palm plantations on abandoned land and displacing plantation areas with low yields of maize and pineapple with sugarcane and cassava. Additionally, shifting the crop calendar could be considered to reduce the stress situation such as the central region can avoid the water scarcity footprint by 38% from shifting sugarcane cultivation. Consequently mitigating this potential impact and threats to the ecosystem based on specific circumstances and context would be achieved through applying the proposed index in water resource and land suitability planning. Full article
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Open AccessArticle Laboratory Tests of Substrate Physical Properties May Not Represent the Retention Capacity of Green Roof Substrates In Situ
Water 2017, 9(12), 920; doi:10.3390/w9120920
Received: 29 September 2017 / Revised: 22 November 2017 / Accepted: 23 November 2017 / Published: 27 November 2017
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Abstract
Green roofs can be used to reduce the volume of polluted stormwater that is generated by cities. Modelling rainfall retention is critical, but green roof water balance models often rely on the physical properties of substrates. In these models, substrate water holding capacity
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Green roofs can be used to reduce the volume of polluted stormwater that is generated by cities. Modelling rainfall retention is critical, but green roof water balance models often rely on the physical properties of substrates. In these models, substrate water holding capacity (WHC) determines the depth of water which can be stored before runoff is generated; whereas, the permanent wilting point (PWP) limits evapotranspiration. The WHC and PWP, as well as plant available water (PAW; where PAW = WHCPWP), as determined from laboratory tests, may not truly reflect how substrates perform on green roofs. We therefore ran a simulated rainfall experiment on green roof modules to (i) compare the rainfall retention of vegetated and non-vegetated substrates with different WHC and PAW, and (ii) relate retention to substrate storage capacity, as calculated from laboratory measures of WHC and PAW. We found that the PAW of a substrate is a better indicator of evapotranspiration and retention when compared with WHC. However, we also found that substrates always retained less water than their calculated storage capacity would suggest, most likely being due to their high permeability. Our results indicate that using laboratory-derived measures of WHC and PAW in green roof models may be over-estimating both evapotranspiration and rainfall retention. Full article
(This article belongs to the Special Issue Hydrological Performance of Green Roofs)
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Open AccessArticle Distribution Patterns of the Freshwater Oligochaete Limnodrilus hoffmeisteri Influenced by Environmental Factors in Streams on a Korean Nationwide Scale
Water 2017, 9(12), 921; doi:10.3390/w9120921
Received: 29 September 2017 / Revised: 8 November 2017 / Accepted: 14 November 2017 / Published: 27 November 2017
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Abstract
Aquatic oligochaetes are very common in streams, and are used as biological assessment indicators as well as in the biological management of organic-enriched systems. In this study, we analyzed the effects of environmental factors influencing the distribution of aquatic oligochaetes Limnodrilus hoffmeisteri in
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Aquatic oligochaetes are very common in streams, and are used as biological assessment indicators as well as in the biological management of organic-enriched systems. In this study, we analyzed the effects of environmental factors influencing the distribution of aquatic oligochaetes Limnodrilus hoffmeisteri in streams. We used 13 environmental factors in three categories (i.e., geography, hydrology, and physicochemistry). Data on the distribution of oligochaetes and environmental factors were obtained from 1159 sampling sites throughout Korea on a nationwide scale. Hierarchical cluster analysis (HCA) and nonmetric multidimensional scaling (NMDS) were performed to analyze the relationships between the occurrence of aquatic oligochaetes and environmental factors. A random forest model was used to evaluate the relative importance of the environmental factors affecting the distribution of oligochaetes. HCA classified sampling sites into four groups according to differences in environmental factors, and NMDS ordination reflected the differences of environmental factors, in particular, water depth, velocity, and altitude, among the four groups defined in the HCA. Furthermore, using a random forest model, turbidity and water velocity were evaluated as highly important factors influencing the distribution of L. hoffmeisteri. Full article
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Open AccessArticle Precipitation Trends over Slovakia in the Period 1981–2013
Water 2017, 9(12), 922; doi:10.3390/w9120922
Received: 22 October 2017 / Revised: 17 November 2017 / Accepted: 20 November 2017 / Published: 27 November 2017
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Abstract
The objective of this paper was to analyze the temporal and spatial trends in annual and seasonal precipitation in Slovakia utilizing 487 gauging station data collected statewide in the period from 1981 to 2013. The nonparametric Mann–Kendall (MK) statistical test, which has been
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The objective of this paper was to analyze the temporal and spatial trends in annual and seasonal precipitation in Slovakia utilizing 487 gauging station data collected statewide in the period from 1981 to 2013. The nonparametric Mann–Kendall (MK) statistical test, which has been widely used to assess the significance of trends in hydrological time series, was applied to detect the significant trends. The Theil–Sen (TS) approach was applied to quantify the trend magnitude, and the Sequential Mann–Kendall (SQMK) test was used to detect abrupt temporal trend shifts. In general, precipitation data in the study area have not changed during the last 33 years, and there are no big gaps. However, predominantly increasing trends in precipitation time series were found at most of the gauging stations in Slovakia. The results corroborate previous climatic studies in the area of central Europe. In Slovakia, there is evidence of different rain distribution from the monthly point of view. Decreasing trends were detected in December in the northern part of Slovakia, while the central and southern parts revealed increasing trends. Most of the stations showed increasing summer precipitation trends, especially in July. It is expected that the findings of this comprehensive study of precipitation trends over Slovakia will produce more insights for the understanding of the regional hydrological behavior in Slovakia over the last several decades. Full article
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Open AccessArticle A Regional Water Optimal Allocation Model Based on the Cobb-Douglas Production Function under Multiple Uncertainties
Water 2017, 9(12), 923; doi:10.3390/w9120923
Received: 17 October 2017 / Revised: 20 November 2017 / Accepted: 22 November 2017 / Published: 8 December 2017
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Abstract
To optimize the water distribution of three industries based on the water demand prediction under multiple uncertainties, a fuzzy credibility-constrained interval two-stage stochastic programming (FCITSP) model base on the Cobb-Douglas production (CD) function was developed. The CD-FCITSP model integrated fuzzy credibility-constrained programming (FCP),
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To optimize the water distribution of three industries based on the water demand prediction under multiple uncertainties, a fuzzy credibility-constrained interval two-stage stochastic programming (FCITSP) model base on the Cobb-Douglas production (CD) function was developed. The CD-FCITSP model integrated fuzzy credibility-constrained programming (FCP), an interval two-stage stochastic programming (ITSP) method and CD function. The developed model could deal with uncertainties with interval, random, and fuzzy features, reflect tradeoffs between different water use sectors, and provide water managers in arid regions with sustainable and reasonable water-allocation schemes under different credibility scenarios of local policies. Moreover, the relationships between economic benefits and water consumption were taken into consideration via the Cobb-Douglas production function. The developed model was applied to support the optimal allocation of limited water resources in Minqin County, northwest China. The obtained solution demonstrated that the developed method could help local water managers to effectively allocate limited water under multiple uncertainties and different credibility scenarios. In addition, water use efficiency could be promoted and the emissions of major pollutants could be reduced. The developed method could be extended to water management practices in other arid regions. Full article
(This article belongs to the collection Water Policy Collection)
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Open AccessArticle Estimating Sediment Flushing Efficiency of a Shaft Spillway Pipe and Bed Evolution in a Reservoir
Water 2017, 9(12), 924; doi:10.3390/w9120924
Received: 9 October 2017 / Revised: 22 November 2017 / Accepted: 22 November 2017 / Published: 28 November 2017
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Abstract
Control of reservoir sedimentation in order to ensure their sustainable use has drawn attention among water engineers and water resource managers. Several methods have been proposed, but most of the developed methodologies are incapable of modelling bed evolutions, while at the same time,
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Control of reservoir sedimentation in order to ensure their sustainable use has drawn attention among water engineers and water resource managers. Several methods have been proposed, but most of the developed methodologies are incapable of modelling bed evolutions, while at the same time, compute sediment flushing efficiency. In this study a two-dimensional bed evolution model is proposed to estimate sediment distribution, bed evolution and sediment flushing efficiency of reservoirs. A-Gong-Dian reservoir, in southern Taiwan, is used as an illustrative example. Typhoon events were used to verify the proposed model. Simulations were conducted for one and two-day storm events under return periods, 2, 5, 10, 25, 50, 100, and 200-year. The results indicated that the average sediment flushing efficiency of the shaft spillway under one and two-day storms were close, 58.50% and 59.39%, respectively. These results were similar to observed laboratory tests experiments, where an efficiency of 65.34% was obtained. This study suggests that the applied model could be adopted to ensure the sustainable use of reservoirs, and also to find an optimal area for the location of a shaft spillway pipe. Therefore, the proposed model could serve as a reference to the reservoir management personnel. Full article
(This article belongs to the Special Issue Adaptive Catchment Management and Reservoir Operation)
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Open AccessArticle Urban Flood Simulation Using Synthetic Storm Drain Networks
Water 2017, 9(12), 925; doi:10.3390/w9120925
Received: 28 September 2017 / Revised: 22 November 2017 / Accepted: 24 November 2017 / Published: 28 November 2017
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Abstract
Recent developments in urban drainage modelling allow for a more realistic coupling of the two-dimensional (2D) surface and one-dimensional (1D) sub-surface drainage domain exchanging water through storm drain inlets instead of a sub-catchment approach based on manholes. Experience has shown, however, that comprehensive
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Recent developments in urban drainage modelling allow for a more realistic coupling of the two-dimensional (2D) surface and one-dimensional (1D) sub-surface drainage domain exchanging water through storm drain inlets instead of a sub-catchment approach based on manholes. Experience has shown, however, that comprehensive records of storm drain inlet locations are often missing or incomplete, preventing users accessing the full benefit of these modelling capabilities. Therefore, this study developed a GIS routine to generate synthetic storm drain inlet locations for the purpose of urban flood modelling. Hydrodynamic model results for a synthetically generated and surveyed storm drain inlet network were obtained using the CityCAT 1D/2D system. On a catchment scale the flow field (surface and flow captured by inlets) simulated by the network of synthetic storm drainage inlets shows satisfactory results when compared with that simulated using the actual network. The results also highlight the sensitivity of the inflows to relatively small changes in terms of the location of storm drain inlets and the effectiveness of storm drain inlets in ponding areas. Full article
(This article belongs to the Special Issue Urban Water Cycle Modelling and Management)
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Open AccessArticle Impact of Spatiotemporal Characteristics of Rainfall Inputs on Integrated Catchment Dissolved Oxygen Simulations
Water 2017, 9(12), 926; doi:10.3390/w9120926
Received: 23 October 2017 / Revised: 17 November 2017 / Accepted: 23 November 2017 / Published: 28 November 2017
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Abstract
Integrated Catchment Modelling aims to simulate jointly urban drainage systems, wastewater treatment plant and rivers. The effect of rainfall input uncertainties in the modelling of individual urban drainage systems has been discussed in several studies already. However, this influence changes when simultaneously simulating
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Integrated Catchment Modelling aims to simulate jointly urban drainage systems, wastewater treatment plant and rivers. The effect of rainfall input uncertainties in the modelling of individual urban drainage systems has been discussed in several studies already. However, this influence changes when simultaneously simulating several urban drainage subsystems and their impact on receiving water quality. This study investigates the effect of the characteristics of rainfall inputs on a large-scale integrated catchment simulator for dissolved oxygen predictions in the River Dommel (The Netherlands). Rainfall products were generated with varying time-aggregation (10, 30 and 60 min) deriving from different sources of data with increasing spatial information: (1) Homogeneous rainfall from a single rain gauge; (2) block kriging from 13 rain gauges; (3) averaged C-Band radar estimation and (4) kriging with external drift combining radar and rain gauge data with change of spatial support. The influence of the different rainfall inputs was observed at combined sewer overflows (CSO) and dissolved oxygen (DO) dynamics in the river. Comparison of the simulations with river monitoring data showed a low sensitivity to temporal aggregation of rainfall inputs and a relevant impact of the spatial scale with a link to the storm characteristics to CSO and DO concentration in the receiving water. Full article
(This article belongs to the Special Issue Quantifying Uncertainty in Integrated Catchment Studies)
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Open AccessArticle An Experimental Study of Two-Phase Pulse Flushing Technology in Water Distribution Systems
Water 2017, 9(12), 927; doi:10.3390/w9120927
Received: 17 October 2017 / Revised: 20 November 2017 / Accepted: 21 November 2017 / Published: 5 December 2017
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Abstract
The deterioration of drinking water during distribution process is caused by many factors. The microorganisms and substances peeling off from the “growth-ring” make the secondary pollution in drinking water distribution systems. To reduce the secondary pollution, two-phase pulse flushing technology is introduced to
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The deterioration of drinking water during distribution process is caused by many factors. The microorganisms and substances peeling off from the “growth-ring” make the secondary pollution in drinking water distribution systems. To reduce the secondary pollution, two-phase pulse flushing technology is introduced to quickly remove the “growth-ring”. In this study, experiment is undertaken for investigating the efficiency of the two-phase pulse flushing and finding the best setting combination. A case study is undertaken to compare the efficiencies between the two-phase pulse and the single-phase flushing. The best setting combination of the two-phase pulse flushing is at the frequency 4 s–6 s (air inflow time is 4 s and air cut off time is 6 s) and the round air inflow nozzle is set at the bottom of the pipe. Two-phase pulse flushing technology can save 95% of water and 6 h 40 min flushing time. Full article
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Open AccessArticle Peat as Substrate for Small-Scale Constructed Wetlands Polishing Secondary Effluents from Municipal Wastewater Treatment Plant
Water 2017, 9(12), 928; doi:10.3390/w9120928
Received: 2 November 2017 / Revised: 18 November 2017 / Accepted: 21 November 2017 / Published: 28 November 2017
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Abstract
With the recent development of constructed wetland technology, it has become a mainstream treatment technology for the mitigation of a variety of wastewaters. This study reports on the treatment performance and pH attenuation capacity of three different configurations of small-scale on-site surface flow
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With the recent development of constructed wetland technology, it has become a mainstream treatment technology for the mitigation of a variety of wastewaters. This study reports on the treatment performance and pH attenuation capacity of three different configurations of small-scale on-site surface flow constructed wetlands (SFCW): T1 (Peat + Typha latifolia), T2 (T. latifolia alone), and T3 (Peat alone) treating secondary effluent from the Amherstview Water Pollution Control Plant (WPCP) for two treatment periods (start-up period and operational period). The aim of this study was to compare the nutrients removal efficiencies between the different treatments, as well as to evaluate the effects of substrate and vegetation on the wetland system. For a hydraulic retention time of 2.5 days, the results showed that all treatment systems could attenuate the pH level during both the start-up and operational periods, while significant nutrient removal performance could only be observed during the operational period. Peat was noted to be a better SFCW substrate in promoting the removal of nitrate (NO3-N), total nitrogen (TN), and phosphorus. The addition of T. latifolia further enhanced NO3-N and TN removal efficiencies, but employing T. latifolia alone did not yield effluents that could meet the regulatory discharge limit (1.0 mg/L) for phosphorus. Full article
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Open AccessArticle Simulating Flash Floods at Hourly Time-Step Using the SWAT Model
Water 2017, 9(12), 929; doi:10.3390/w9120929
Received: 6 October 2017 / Revised: 8 November 2017 / Accepted: 23 November 2017 / Published: 28 November 2017
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Abstract
Flash floods are natural phenomena with environmental, social and economic impacts. To date, few numerical models are able to simulate hydrological processes at catchment scale at a reasonable time scale to describe flash events with accurate details. Considering a ~810 km2 Mediterranean
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Flash floods are natural phenomena with environmental, social and economic impacts. To date, few numerical models are able to simulate hydrological processes at catchment scale at a reasonable time scale to describe flash events with accurate details. Considering a ~810 km2 Mediterranean river coastal basin (southwestern France) as a study case, the objective of the present study was to assess the ability of the sub-daily module of the lumped Soil and Water Assessment Tool (SWAT) to simulate discharge (1) time-continuously, by testing two sub-basin delineation schemes, two catchment sizes, and two output time-steps; and (2) at flood time-scale, by comparing the performances of SWAT to the performances of the event-based fully distributed MARINE model when simulating flash flood events. We showed that there was no benefit of decreasing the size of the minimum drainage area (e.g., from ~15 km2 down to ~1 km2) when delineating sub-basins in SWAT. We also showed that both the MARINE and SWAT models were equally able to reproduce peak discharge, flood timing and volume, and that they were both limited by rainfall and soil data. Hence, the SWAT model appears to be a reliable modelling tool to predict discharge over long periods of time in large flash-flood-prone basins. Full article
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Open AccessArticle Quantifying Effectiveness of Streambank Stabilization Practices on Cedar River, Nebraska
Water 2017, 9(12), 930; doi:10.3390/w9120930
Received: 15 September 2017 / Revised: 20 November 2017 / Accepted: 26 November 2017 / Published: 29 November 2017
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Abstract
Excessive sediment is a major pollutant to surface waters worldwide. In some watersheds, streambanks are a significant source of this sediment, leading to the expenditure of billions of dollars in stabilization projects. Although costly streambank stabilization projects have been implemented worldwide, long-term monitoring
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Excessive sediment is a major pollutant to surface waters worldwide. In some watersheds, streambanks are a significant source of this sediment, leading to the expenditure of billions of dollars in stabilization projects. Although costly streambank stabilization projects have been implemented worldwide, long-term monitoring to quantify their success is lacking. There is a critical need to document the long-term success of streambank restoration projects. The objectives of this research were to (1) quantify streambank retreat before and after the stabilization of 18 streambanks on the Cedar River in North Central Nebraska, USA; (2) assess the impact of a large flood event; and (3) determine the most cost-efficient stabilization practice. The stabilized streambanks included jetties (10), rock-toe protection (1), slope reduction/gravel bank (1), a retaining wall (1), rock vanes (2), and tree revetments (3). Streambank retreat and accumulation were quantified using aerial images from 1993 to 2016. Though streambank retreat has been significant throughout the study period, a breached dam in 2010 caused major flooding and streambank erosion on the Cedar River. This large-scale flood enabled us to quantify the effect of one extreme event and evaluate the effectiveness of the stabilized streambanks. With a 70% success rate, jetties were the most cost-efficient practice and yielded the most deposition. If minimal risk is unacceptable, a more costly yet immobile practice such as a gravel bank or retaining wall is recommended. Full article
(This article belongs to the Special Issue Streambank Erosion: Monitoring, Modeling and Management)
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Open AccessArticle Effects of Using High-Density Rain Gauge Networks and Weather Radar Data on Urban Hydrological Analyses
Water 2017, 9(12), 931; doi:10.3390/w9120931
Received: 7 October 2017 / Revised: 27 November 2017 / Accepted: 28 November 2017 / Published: 29 November 2017
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Abstract
Flood prediction is difficult in urban areas because only sparse gauge data and radar data of low accuracy are usually used to analyze flooding and inundation. Sub-basins of urban areas are extremely small, so rainfall data of high spatial resolution are required for
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Flood prediction is difficult in urban areas because only sparse gauge data and radar data of low accuracy are usually used to analyze flooding and inundation. Sub-basins of urban areas are extremely small, so rainfall data of high spatial resolution are required for analyzing complex drainage systems with high spatial variability. This study aimed to produce three types of quantitative precipitation estimation (QPE) products using rainfall data that was derived from 190 gauges, including the new high-density rain-gauge network operated by the SK Planet company, and the automated weather stations of the Korea Meteorological Administration, along with weather radar data. This study also simulated urban runoff for the Gangnam District of Seoul, South Korea, using the obtained QPE products to evaluate hydraulic and hydrologic impacts according to three rainfall fields. The accuracy of this approach was assessed in terms of the amount and spatial distribution of rainfall in an urban area. The QPE products provided highly accurate results and simulations of peak runoff and overflow phenomena. They also accurately described the spatial variability of the rainfall fields. Overall, the integration of high-density gauge data with radar data proved beneficial for quantitative rainfall estimation. Full article
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Open AccessArticle Ecological Effects of Grazing in the Northern Tianshan Mountains
Water 2017, 9(12), 932; doi:10.3390/w9120932
Received: 17 September 2017 / Revised: 17 November 2017 / Accepted: 25 November 2017 / Published: 29 November 2017
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Abstract
Identifying the effects of grazing is critical for the conservation, protection and sustainable use of arid grassland ecosystems. However, research regarding the ecological effects of grazing along mountainous elevation gradients is limited in arid areas, particularly at the regional scale. Using the Biome-BGC
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Identifying the effects of grazing is critical for the conservation, protection and sustainable use of arid grassland ecosystems. However, research regarding the ecological effects of grazing along mountainous elevation gradients is limited in arid areas, particularly at the regional scale. Using the Biome-BGC grazing model, we explored the effects of grazing on grassland net primary productivity (NPP), evapotranspiration (ET) and water use efficiency (WUE) from 1979 to 2012 along an elevation gradient in the northern Tianshan Mountains. The NPP, ET and WUE values were generally lower under the grazing scenario than under the ungrazed scenario; the differences between the grazing and ungrazed scenarios showed increasing trends over time; and distinct spatial heterogeneity in these differences was observed. Distinct decreases in NPP and WUE under the grazing scenario mainly occurred in regions with high livestock consumption. The decrease in ET was greater in mountainous areas with high grazing intensity due to decreased transpiration and increased surface runoff. This study contributes to a better understanding of the ecological effects of grazing along an elevation gradient in the northern Tianshan Mountains and provides data to support the scientific management of grassland ecosystems. Full article
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Open AccessArticle The Pluralistic Water Research Concept: A New Human-Water System Research Approach
Water 2017, 9(12), 933; doi:10.3390/w9120933
Received: 2 November 2017 / Revised: 15 November 2017 / Accepted: 22 November 2017 / Published: 30 November 2017
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Abstract
The use and management of water systems is influenced by a number of factors, such as economic growth, global change (e.g., urbanization, hydrological-climatic changes), politics, history and culture. Despite noteworthy efforts to develop integrative approaches to analyze water-related problems, human-water research remains a
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The use and management of water systems is influenced by a number of factors, such as economic growth, global change (e.g., urbanization, hydrological-climatic changes), politics, history and culture. Despite noteworthy efforts to develop integrative approaches to analyze water-related problems, human-water research remains a major challenge for scholars and decision makers due to the increasing complexity of human and water systems interactions. Although existing concepts try to integrate the social and water dimensions, they usually have a disciplinary starting point and perspective, which can represent an obstacle to true integration in human-water research. Hence, a pluralistic approach is required to better understand the interactions between human and water systems. This paper discusses prominent human-water concepts (Integrated Water Resources Management (IWRM), socio-hydrology, and political ecology/hydrosocial approach) and presents a newly developed concept termed pluralistic water research (PWR). This is not only a pluralistic but also an integrative and interdisciplinary approach which aims to coherently and comprehensively integrate human-water dimensions. The different concepts are illustrated in a synopsis, and diverse framing of research questions are exemplified. The PWR concept integrates physical and social sciences, which enables a comprehensive analysis of human-water interactions and relations. This can lead to a better understanding of water-related issues and potentially sustainable trajectories. Full article
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Open AccessArticle Water Security in Times of Climate Change and Intractability: Reconciling Conflict by Transforming Security Concerns into Equity Concerns
Water 2017, 9(12), 934; doi:10.3390/w9120934
Received: 30 August 2017 / Revised: 17 November 2017 / Accepted: 25 November 2017 / Published: 1 December 2017
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Abstract
This paper considers how to achieve equitable water governance and the flow-on effects it has in terms of supporting sustainable development, drawing on case studies from the international climate change adaptation and governance project (CADWAGO). Water governance, like many other global issues, is
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This paper considers how to achieve equitable water governance and the flow-on effects it has in terms of supporting sustainable development, drawing on case studies from the international climate change adaptation and governance project (CADWAGO). Water governance, like many other global issues, is becoming increasingly intractable (wicked) with climate change and is, by the international community, being linked to instances of threats to human security, the war in the Sudanese Darfur and more recently the acts of terrorism perpetuated by ISIS. In this paper, we ask the question: how can situations characterized by water controversy (exacerbated by the uncertainties posed by climate change) be reconciled? The main argument is based on a critique of the way the water security discourse appropriates expert (normal) claims about human-biophysical relationships. When water challenges become increasingly securitized by the climate change discourse it becomes permissible to enact processes that legitimately transgress normative positions through post-normal actions. In contrast, the water equity discourse offers an alternative reading of wicked and post-normal water governance situations. We contend that by infusing norm critical considerations into the process of securitization, new sub-national constellations of agents will be empowered to enact changes; thereby bypassing vicious cycles of power brokering that characterize contemporary processes intended to address controversies. Full article
Open AccessFeature PaperArticle Lignin Biodegradation in Pulp-and-Paper Mill Wastewater by Selected White Rot Fungi
Water 2017, 9(12), 935; doi:10.3390/w9120935
Received: 20 October 2017 / Revised: 27 November 2017 / Accepted: 29 November 2017 / Published: 2 December 2017
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Abstract
An investigation has been carried out to explore the lignin-degrading ability of white rot fungi, as B. adusta and P. crysosporium, grown in different media containing (i) glucose and mineral salts; (ii) a dairy residue; (iii) a dairy residue and mineral salts.
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An investigation has been carried out to explore the lignin-degrading ability of white rot fungi, as B. adusta and P. crysosporium, grown in different media containing (i) glucose and mineral salts; (ii) a dairy residue; (iii) a dairy residue and mineral salts. Both fungi were then used as inoculum to treat synthetic and industrial pulp-and-paper mill wastewater. On synthetic wastewater, up to 97% and 74% of lignin degradation by B. adusta and P. crysosporium, respectively, have been reached. On industrial wastewater, both fungal strains were able to accomplish 100% delignification in 8–10 days, independent from pH control, with a significant reduction of total organic carbon (TOC) of the solution. Results have confirmed the great biotechnological potential of both B. adusta and P. crysosporium for complete lignin removal in industrial wastewater, and can open the way to next industrial applications on large scale. Full article
(This article belongs to the Special Issue Recent Advances in Water Management: Saving, Treatment and Reuse)
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Open AccessArticle Hydraulic Parameter Generation Technique Using a Discrete Fracture Network with Bedrock Heterogeneity in Korea
Water 2017, 9(12), 937; doi:10.3390/w9120937
Received: 14 September 2017 / Revised: 19 November 2017 / Accepted: 28 November 2017 / Published: 1 December 2017
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Abstract
In instances of damage to engineered barriers containing nuclear waste material, surrounding bedrock is a natural barrier that retards radionuclide movement by way of adsorption and delay due to groundwater flow through highly tortuous fractured rock pathways. At the Gyeongju nuclear waste disposal
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In instances of damage to engineered barriers containing nuclear waste material, surrounding bedrock is a natural barrier that retards radionuclide movement by way of adsorption and delay due to groundwater flow through highly tortuous fractured rock pathways. At the Gyeongju nuclear waste disposal site, groundwater mainly flows through granitic and sedimentary rock fractures. Therefore, to understand the nuclide migration path, it is necessary to understand discrete fracture networks based on heterogeneous fracture orientations, densities, and size characteristics. In this study, detailed heterogeneous fracture distribution, including the density and orientation of the fractures, was considered for a region that has undergone long periods of change from various geological activities at and around the Gyeongju site. A site-scale discrete fracture network (DFN) model was constructed taking into account: (i) regional fracture heterogeneity constrained by a multiple linear regression analysis of fracture intensity on faults and electrical resistivity; and (ii) the connectivity of conductive fractures having fracture hydraulic parameters, using transient flow simulation. Geometric and hydraulic heterogeneity of the DFN was upscaled into equivalent porous media for flow and transport simulation for a large-scale model. Full article
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Open AccessArticle Characteristics and Factors Influencing the Hysteresis of Water Area–Stage Curves for Poyang Lake
Water 2017, 9(12), 938; doi:10.3390/w9120938
Received: 22 October 2017 / Revised: 28 November 2017 / Accepted: 29 November 2017 / Published: 7 December 2017
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Abstract
Flood dynamics of large lake floodplain systems are typically complex. This paper analyses the characteristics and factors that influence the hysteresis of water area–stage curves for Poyang Lake, the largest freshwater lake in China characterized by complex geomorphology and upstream–downstream exchange conditions. For
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Flood dynamics of large lake floodplain systems are typically complex. This paper analyses the characteristics and factors that influence the hysteresis of water area–stage curves for Poyang Lake, the largest freshwater lake in China characterized by complex geomorphology and upstream–downstream exchange conditions. For this purpose, a two-dimensional hydrodynamic model (EFDC) based on seven scenarios is established. The results indicate that the area–stage curve presents significant hysteretic characteristics due to different water surface gradients that emerge during the water-rising and water-falling periods. Counter-clockwise, clockwise, and splayed hysteresis directions observed at the northern, southern, and central hydrometric stations, respectively, are found in Poyang Lake for the first time. Upstream catchment inflows and Hukou stage reflecting the downstream condition are the main factors that influence hysteresis. The temporal fluctuation of catchment inflows and Hukou stage has a remarkably positive impact on hysteresis, namely, an increase in fluctuation brings about a larger hysteresis. The effects of magnitude change in the two factors on hysteresis are opposing. Catchment inflows are positively related, while the decline of the Hukou stage will produce a more pronounced hysteresis. The outcomes of this study will benefit the water management of Poyang Lake and other similar large lakes. Full article
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Open AccessFeature PaperArticle Scoping for the Operation of Agile Urban Adaptation for Secondary Cities of the Global South: Possibilities in Pune, India
Water 2017, 9(12), 939; doi:10.3390/w9120939
Received: 8 November 2017 / Revised: 27 November 2017 / Accepted: 29 November 2017 / Published: 2 December 2017
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Abstract
Urban areas, especially in developing countries, are adapting to deficits in infrastructure and basic services (Type I adaptation) and to adaptation gaps in response to current and future climatic, societal and economic change (Type II adaptation). The responses to these adaptations needs can
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Urban areas, especially in developing countries, are adapting to deficits in infrastructure and basic services (Type I adaptation) and to adaptation gaps in response to current and future climatic, societal and economic change (Type II adaptation). The responses to these adaptations needs can be integrated and implemented using an “agile urban adaptation process”, i.e., an adaptive planning process quickly adapting to change in a flexible manner in short planning horizons, where the requirements and responses evolve through evolutionary development, early delivery, continuous improvement and collaboration between self-organizing and cross-functional teams. This paper focuses on how to move from the current conceptual stage to developing practical knowledge for the operation of agile urban adaptation. Scoping methodology comprises (i) understanding and structuring the adaptation context; (ii) exploring the four agile elements—balancing type I & II adaptation needs, flexibility, range of scenarios and involvement of stakeholders—in the adaptation context; (iii) a detailed SWOT analysis (strength, weakness, opportunities and threat) of adaptation responses; (iv) mapping relationships and synergies between the adaptation responses; and (v) preparing agility score cards for adaptation responses. The scoping exercise revealed that the agile adaptation process can move from concept to operation in Pune, India where the city is improving the basic services and adapting to climate change. For example: conventional adaptation responses such as city greening and check-dams across the rivers have agile characteristics; these responses are synergetic with other adaptation responses; and, there is a possibility to compare conventional adaptation responses based on agile characteristics. This scoping exercise also reveals that urban agile adaptation is not about implementing novel adaptation responses but understanding, planning and implementing conventional adaptation responses using an agile perspective. Urban agile adaptation is also about mainstreaming agile ideas using traditional adaptation responses. Hence, it is possible to apply agile the urban adaptation process using conventional adaptation responses in urban areas which address adaptation deficits related to infrastructure development as well as climate and socio-economic adaptation. Full article
(This article belongs to the Special Issue Sponge Cities: Emerging Approaches, Challenges and Opportunities)
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Open AccessArticle Should We Leave? Attitudes towards Relocation in Response to Sea Level Rise
Water 2017, 9(12), 941; doi:10.3390/w9120941
Received: 9 October 2017 / Revised: 21 November 2017 / Accepted: 1 December 2017 / Published: 4 December 2017
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Abstract
The participation of individuals contributes significantly to the success of sea level rise adaptation. This study therefore addresses what influences people’s likelihood of relocating away from low-lying areas in response to rising sea levels. The analysis was based on a survey conducted in
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The participation of individuals contributes significantly to the success of sea level rise adaptation. This study therefore addresses what influences people’s likelihood of relocating away from low-lying areas in response to rising sea levels. The analysis was based on a survey conducted in the City of Panama Beach in Florida (USA). Survey items relate to people’s risk perception, hazard experience, threat appraisal, and coping appraisal, whose theoretical background is Protection Motivation Theory. Descriptive and correlation analysis was first performed to highlight critical factors which were then examined by a multinomial Logit model. Results show that sea level rise awareness is the major explanatory variable. Coping appraisal is qualitatively viewed as a strong predictor for action, while threat appraisal is statistically significant in driving relocation intention. These factors should be integrated in current risk communication regarding sea level rise. Full article
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Open AccessArticle Comparison of Saturated Hydraulic Conductivity Estimated by Three Different Methods
Water 2017, 9(12), 942; doi:10.3390/w9120942
Received: 7 November 2017 / Revised: 29 November 2017 / Accepted: 1 December 2017 / Published: 4 December 2017
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Abstract
This study compares saturated hydraulic conductivities (Ks) of three sandy soils such as coarse, medium and fine sand. The Ks was obtained using three different methods: empirical methods based on the grain size analysis, the relative effective porosity model
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This study compares saturated hydraulic conductivities ( K s ) of three sandy soils such as coarse, medium and fine sand. The K s was obtained using three different methods: empirical methods based on the grain size analysis, the relative effective porosity model (REPM), and breakthrough curve analyses based on tracer tests. Column drainage tests were performed to characterize the water retention properties of the samples, which are required in the REPM. Bench scale tracer tests with various conditions were conducted to obtain reasonable linear velocities of the samples using breakthrough curve analyses and then K s was estimated using Darcy’s law. For the REPM, the differences of K s for the coarse and fine sand soils were less than one order of magnitude; however, the difference of K s values between the empirical methods and the breakthrough curve analyses was larger than one order of magnitude. The comparison results suggest that the REPM can be a reliable method for estimating K s for soil grains, and is cost effective due to its experimental simplicity. Full article
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Open AccessArticle Changes in Extreme Precipitation: A Case Study in the Middle and Lower Reaches of the Yangtze River in China
Water 2017, 9(12), 943; doi:10.3390/w9120943
Received: 20 September 2017 / Revised: 29 November 2017 / Accepted: 30 November 2017 / Published: 4 December 2017
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Abstract
Monitoring extreme climate events is of great importance, mainly due to increasingly severe impacts of extreme climate on nature and humanity. However, the characteristics of extreme climate events, especially extreme precipitation, frequently show complex variations in the context of climate change. Taking the
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Monitoring extreme climate events is of great importance, mainly due to increasingly severe impacts of extreme climate on nature and humanity. However, the characteristics of extreme climate events, especially extreme precipitation, frequently show complex variations in the context of climate change. Taking the middle and lower reaches of the Yangtze River (MLR-YR) in China as a case study, extreme daily precipitation during 1961–2012 was analyzed from the aspects of frequency and intensity. The changes in extreme daily precipitation in the MLR-YR were further attributed to several factors, including large-scale circulation, hydrologic engineering and local topography. Our analyses indicate that both frequency and intensity of the extreme daily precipitation in the MLR-YR showed overall increasing trends from 1961 to 2012. The increase could be associated with weakened East Asian summer monsoon in past decades. In addition, inverse trends could also be found locally between the frequency and the intensity. For instance, extreme precipitation intensity revealed an enhanced trend in the western part of the middle reach of the Yangtze River, while extreme precipitation frequency showed decreasing trends in this region. These phenomena could be associated with the effects of some local factors (e.g., lake regulation, hydropower engineering, topography). Our study highlights the important role of local factors on extreme precipitation changes. Full article
(This article belongs to the Special Issue Impact of Climate on Hydrological Extremes)
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Open AccessFeature PaperArticle Quantifying Roughness Coefficient Uncertainty in Urban Flooding Simulations through a Simplified Methodology
Water 2017, 9(12), 944; doi:10.3390/w9120944
Received: 10 October 2017 / Revised: 29 November 2017 / Accepted: 30 November 2017 / Published: 4 December 2017
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Abstract
A methodology is presented which can be used in the evaluation of parametric uncertainty in urban flooding simulation. Due to the fact that such simulations are time consuming, the following methodology is proposed: (a) simplification of the description of the physical process; (b)
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A methodology is presented which can be used in the evaluation of parametric uncertainty in urban flooding simulation. Due to the fact that such simulations are time consuming, the following methodology is proposed: (a) simplification of the description of the physical process; (b) derivation of a training data set; (c) development of a data-driven surrogate model; (d) use of a forward uncertainty propagation scheme. The simplification comprises the following steps: (a) unit hydrograph derivation using a 2D hydrodynamic model; (b) calculation of the losses in order to determine the effective rainfall depth; (c) flood event simulation using the principle of the proportionality and superposition. The above methodology was implemented in an urban catchment located in the city of Athens, Greece. The model used for the first step of the simplification was FLOW-R2D, whereas the well-known SWMM software (US Environmental Protection Agency, Washington, DC, USA) was used for the second step of the simplification. For the training data set derivation, an ensemble of 100 Unit Hydrographs was derived with the FLOW-R2D model. The parameters which were modified in order to produce this ensemble were the Manning coefficients in the two friction zones (residential and urban open space areas). The surrogate model used to replicate the unit hydrograph derivation, using the Manning coefficients as an input, was based on the Polynomial Chaos Expansion technique. It was found that, although the uncertainties in the derived results have to be taken into account, the proposed methodology can be a fast and efficient way to cope with dynamic flood simulation in an urban catchment. Full article
(This article belongs to the Special Issue Quantifying Uncertainty in Integrated Catchment Studies)
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Open AccessArticle An Experimental Study of Hydraulic Jump in a Gradually Expanding Rectangular Stilling Basin with Roughened Bed
Water 2017, 9(12), 945; doi:10.3390/w9120945
Received: 25 August 2017 / Revised: 28 November 2017 / Accepted: 30 November 2017 / Published: 7 December 2017
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Abstract
The paper presents the results of an experimental study carried out to investigate the effect of geometric and hydraulic parameters on energy dissipation and location of the hydraulic jump, with a change in the height of roughness elements and the divergence of walls
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The paper presents the results of an experimental study carried out to investigate the effect of geometric and hydraulic parameters on energy dissipation and location of the hydraulic jump, with a change in the height of roughness elements and the divergence of walls in different discharges. Experiments were conducted in a horizontal rectangular basin with gradual expansion 0.5 m wide and 10 m long. Four physical models were fixed in the flume. The measured characteristics of the hydraulic jump with different divergences ratio (B = b1/b2 = 0.4, 0.6, 0.8, 1) and the inflow Froude numbers (6 < Fr1 < 12) were compared with each other and with the corresponding values measured for the classical hydraulic jump. The results showed that the tailwater depth required to form a hydraulic jump and also the roller length of the hydraulic jump and the length of the hydraulic jump on a gradual expansion basin with the rough bed were appreciably smaller than that of the corresponding hydraulic jumps in a rectangular basin with smooth and rough bed. With the experimental data, empirical formulae were developed to express the hydraulic jump characteristics relating to roughness elements height and divergence ratio of wall. Also, the applicability of some empirical relationships for estimating the roller length was tested. Full article
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Open AccessArticle A Statistical Method to Predict Flow Permanence in Dryland Streams from Time Series of Stream Temperature
Water 2017, 9(12), 946; doi:10.3390/w9120946
Received: 12 October 2017 / Revised: 30 November 2017 / Accepted: 1 December 2017 / Published: 5 December 2017
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Abstract
Intermittent and ephemeral streams represent more than half of the length of the global river network. Dryland freshwater ecosystems are especially vulnerable to changes in human-related water uses as well as shifts in terrestrial climates. Yet, the description and quantification of patterns of
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Intermittent and ephemeral streams represent more than half of the length of the global river network. Dryland freshwater ecosystems are especially vulnerable to changes in human-related water uses as well as shifts in terrestrial climates. Yet, the description and quantification of patterns of flow permanence in these systems is challenging mostly due to difficulties in instrumentation. Here, we took advantage of existing stream temperature datasets in dryland streams in the northwest Great Basin desert, USA, to extract critical information on climate-sensitive patterns of flow permanence. We used a signal detection technique, Hidden Markov Models (HMMs), to extract information from daily time series of stream temperature to diagnose patterns of stream drying. Specifically, we applied HMMs to time series of daily standard deviation (SD) of stream temperature (i.e., dry stream channels typically display highly variable daily temperature records compared to wet stream channels) between April and August (2015–2016). We used information from paired stream and air temperature data loggers as well as co-located stream temperature data loggers with electrical resistors as confirmatory sources of the timing of stream drying. We expanded our approach to an entire stream network to illustrate the utility of the method to detect patterns of flow permanence over a broader spatial extent. We successfully identified and separated signals characteristic of wet and dry stream conditions and their shifts over time. Most of our study sites within the entire stream network exhibited a single state over the entire season (80%), but a portion of them showed one or more shifts among states (17%). We provide recommendations to use this approach based on a series of simple steps. Our findings illustrate a successful method that can be used to rigorously quantify flow permanence regimes in streams using existing records of stream temperature. Full article
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Open AccessArticle Measurement and Simulation of Soil Water Contents in an Experimental Field in Delta Plain
Water 2017, 9(12), 947; doi:10.3390/w9120947
Received: 8 October 2017 / Revised: 27 November 2017 / Accepted: 2 December 2017 / Published: 6 December 2017
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Abstract
Variation in soil water content in the delta plain has its own particularity and is significant for agricultural improvement, the utilization of water resources and flood risk mitigation. In this study, experimental data collected from a plot of farmland located in the Taihu
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Variation in soil water content in the delta plain has its own particularity and is significant for agricultural improvement, the utilization of water resources and flood risk mitigation. In this study, experimental data collected from a plot of farmland located in the Taihu Basin were used to investigate the temporal and vertical variation of soil water content, as well as the effects of individual rainfall on soil water and shallow groundwater and their interaction. The results showed that the variation of soil water content is dependent on the comprehensive influence of soil hydraulic properties, meteorological factors and shallow groundwater and the correlation to the groundwater table is the strongest due to the significant capillary action in the delta plain. A saturated-unsaturated three-dimensional soil water numerical model was developed for the study area in response to rainfall and evapotranspiration. Scenario simulations were performed with different soil depths for soil water content and the error source was analyzed to improve the model. The average RMSE, RE and R2 values of the soil water content at the five depths between the measured and simulated results were 0.0192 cm3·cm−3, 2.09% and 0.8119, respectively. The results indicated that the developed model could estimate vertical soil water content and its dynamics over time at the study site at an acceptable level. Moreover, further research and application to other sites in delta plains are necessary to verify and improve the model. Full article
(This article belongs to the Special Issue Soil Water Conservation: Dynamics and Impact)
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Open AccessArticle Estimating Aquifer Transmissivity Using the Recession-Curve-Displacement Method in Tanzania’s Kilombero Valley
Water 2017, 9(12), 948; doi:10.3390/w9120948
Received: 27 October 2017 / Revised: 28 November 2017 / Accepted: 2 December 2017 / Published: 6 December 2017
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Abstract
Information on aquifer processes and characteristics across scales has long been a cornerstone for understanding water resources. However, point measurements are often limited in extent and representativeness. Techniques that increase the support scale (footprint) of measurements or leverage existing observations in novel ways
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Information on aquifer processes and characteristics across scales has long been a cornerstone for understanding water resources. However, point measurements are often limited in extent and representativeness. Techniques that increase the support scale (footprint) of measurements or leverage existing observations in novel ways can thus be useful. In this study, we used a recession-curve-displacement method to estimate regional-scale aquifer transmissivity (T) from streamflow records across the Kilombero Valley of Tanzania. We compare these estimates to local-scale estimates made from pumping tests across the Kilombero Valley. The median T from the pumping tests was 0.18 m2/min. This was quite similar to the median T estimated from the recession-curve-displacement method applied during the wet season for the entire basin (0.14 m2/min) and for one of the two sub-basins tested (0.16 m2/min). On the basis of our findings, there appears to be reasonable potential to inform water resource management and hydrologic model development through streamflow-derived transmissivity estimates, which is promising for data-limited environments facing rapid development, such as the Kilombero Valley. Full article
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Open AccessArticle Stormwater Biofilters as Barriers against Campylobacter jejuni, Cryptosporidium Oocysts and Adenoviruses; Results from a Laboratory Trial
Water 2017, 9(12), 949; doi:10.3390/w9120949
Received: 24 September 2017 / Revised: 22 November 2017 / Accepted: 1 December 2017 / Published: 6 December 2017
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Abstract
Biofilters are a widely used stormwater treatment technology. However; other than some evidence regarding non-pathogenic indicator microorganisms; there are significant knowledge gaps in the capacity of stormwater biofilters to remove actual pathogens and how this removal is impacted by biofilter design elements and
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Biofilters are a widely used stormwater treatment technology. However; other than some evidence regarding non-pathogenic indicator microorganisms; there are significant knowledge gaps in the capacity of stormwater biofilters to remove actual pathogens and how this removal is impacted by biofilter design elements and operational conditions. In this study; we explored the capacity of stormwater biofilters to remove three reference pathogens (Campylobacter spp.; adenovirus and Cryptosporidium oocysts) and compared these to commonly used indicator microorganisms (E. coli; FRNA coliphages and Clostridium perfringens). Two different biofilter designs; each having a submerged zone (SZ); were tested under extended dry weather periods (up to 4 weeks) and different event volumes (the equivalent of 1–2 pore volumes) in a laboratory trial. These systems were able to consistently reduce the concentrations of all tested reference pathogens (average log reduction in Campylobacter spp. = 0.7; adenovirus = 1.0 and Cryptosporidium oocysts = 1.7) and two of the indicators (average log reduction in E. coli = 1.2 and C. perfringens = 2.1). However; none of the tested indicators consistently mimicked the removal performance of their corresponding reference pathogens after extended dry weather periods and during larger simulated storm events. This indicates that the behaviour of these pathogens in stormwater biofilters are not adequately represented by their corresponding indicator microorganisms and that to optimise biofilter designs for pathogen removal it is critical to further study pathogen removal processes in these systems. Full article
(This article belongs to the Special Issue Advances on Urban Stormwater Harvesting Strategies)
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Open AccessFeature PaperArticle Modeling Stream Bank Erosion: Practical Stream Results and Future Needs
Water 2017, 9(12), 950; doi:10.3390/w9120950
Received: 12 October 2017 / Revised: 29 November 2017 / Accepted: 30 November 2017 / Published: 6 December 2017
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Abstract
Coupled two-dimensional (2D) morphodynamic and bank erosion models are gaining attentions in recent years. It has been shown that such models have advantages over the one-dimensional (1D) modeling approaches. In this paper, a previous 2D bank erosion model with the moving mesh method
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Coupled two-dimensional (2D) morphodynamic and bank erosion models are gaining attentions in recent years. It has been shown that such models have advantages over the one-dimensional (1D) modeling approaches. In this paper, a previous 2D bank erosion model with the moving mesh method is extended to include the fixed mesh approach. Further, two practical streams with differing complexity are simulated to demonstrate the extended model. Both the moving mesh and fixed mesh methods are used in the modeling. The model consists of two components: a 2D flow and mobile-bed model for vertical bed changes and hydraulic forces acting on a bank and a lateral bank retreat model. The 2D vertical model and the lateral bank erosion model are coupled together spatially and temporally through a special procedure and a common mesh. With the experiences gained with practical stream modeling, the modeling procedure and key model input parameters are described. The study shows that the moving and fixed mesh methods together make the extended bank erosion model numerically robust and capable of predicting both the vertical bed changes and the lateral stream bank erosion for complex streams. Each individual method, however, has its own limitations in terms of model accuracy and efficiency. The moving mesh works well if bank retreat is relatively small, e.g., less than one channel width, and produces more accurate results than the fixed mesh method. The fixed mesh may be needed for ensuring numerical stability if a bank may be subject to significant retreat (e.g., more than one channel width). The fixed mesh method, however, is less accurate than the moving mesh method and a much refined mesh may be needed. Both methods need future research and improvements in terms of their model accuracy. Full article
(This article belongs to the Special Issue Streambank Erosion: Monitoring, Modeling and Management)
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Open AccessArticle Effect of Temperature Rising on the Stygobitic Crustacean Species Diacyclops belgicus: Does Global Warming Affect Groundwater Populations?
Water 2017, 9(12), 951; doi:10.3390/w9120951
Received: 27 October 2017 / Revised: 23 November 2017 / Accepted: 4 December 2017 / Published: 7 December 2017
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Abstract
The average global temperature is predicted to increase by 3 °C by the end of this century due to human-induced climate change. The overall metabolism of the aquatic biota will be directly affected by rising temperatures and associated changes. Since thermal stability is
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The average global temperature is predicted to increase by 3 °C by the end of this century due to human-induced climate change. The overall metabolism of the aquatic biota will be directly affected by rising temperatures and associated changes. Since thermal stability is a characteristic of groundwater ecosystems, global warming is expected to have a profound effect on the groundwater fauna. The prediction that stygobitic (obligate groundwater dweller) species are vulnerable to climate change includes assumptions about metabolic effects that can only be tested by comparisons across a thermal gradient. To this end, we investigated the effects of two different thermal regimes on the metabolism of the stygobitic copepod species Diacyclops belgicus (Kiefer, 1936). We measured the individual-based oxygen consumption of this species as a proxy of possible metabolic reactions to temperature rising from 14 to 17 °C. We used a sealed glass microplate equipped with planar oxygen sensor spots with optical isolation glued onto the bottom of 80-μL wells integrated with a 24-channel fluorescence-based respirometry system. The tests have provided controversial results according to which the D. belgicus populations should be prudently considered at risk under a global warming scenario. Full article
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Open AccessArticle Simulation of Pan Evaporation and Application to Estimate the Evaporation of Juyan Lake, Northwest China under a Hyper-Arid Climate
Water 2017, 9(12), 952; doi:10.3390/w9120952
Received: 30 October 2017 / Revised: 1 December 2017 / Accepted: 5 December 2017 / Published: 7 December 2017
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Abstract
Because of its nature, lake evaporation (EL) is rarely measured directly. The most common method used is to apply a pan coefficient (Kp) to the measured pan evaporation (Ep). To reconstruct the long sequence
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Because of its nature, lake evaporation (EL) is rarely measured directly. The most common method used is to apply a pan coefficient (Kp) to the measured pan evaporation (Ep). To reconstruct the long sequence dataset of Ep, this study firstly determined the conversion coefficients of Ep of two pans (φ20 and E601, each applied to a different range of years) measured synchronously at the nearest meteorological station during the unfrozen period through 1986 to 2001, and then Ep was estimated by the PenPan model that developed to the Class A pan and applied to quantify the EL of the Juyan Lake, located in the hyper-arid area of northwest China. There was a significantly linear relationship between the E601 and φ20 with the conversion coefficients of 0.60 and 0.61 at daily and monthly time scales, respectively. The annual Ep based on monthly conversion coefficients was estimated at 2240.5 mm and decreased by 6.5 mm per year, which was consistent with the declining wind speed (U) during the 60 years from 1957 to 2016. The Ep simulated by the PenPan model with the modified net radiation (Rn) had better performance (compared to Ep measured by E601) than the original PenPan model, which may be attributed to the overestimated Rn under the surface of E601 that was embedded in the soil rather than above the ground similar to the Class A and φ20. The measured monthly EL and Ep has a significantly linear relationship during the unfrozen period in 2014 and 2015, but the ratio of Ep to EL, i.e., Kp varied within the year, with an average of 0.79, and was logarithmically associated with U. The yearly mean EL with full lake area from 2005 to 2015 was 1638.5 mm and 1385.6 mm, calculated by the water budget and the PenPan model with the modified Rn, respectively; the latter was comparable to the surface runoff with an average of 1462.9 mm. In conclusion, the PenPan model with the modified Rn has good performance in simulating Ep of the E601, and by applying varied Kp to the model we can improve the estimates of lake evaporation. Full article
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Open AccessArticle Spatial Evaluation of Multiple Benefits to Encourage Multi-Functional Design of Sustainable Drainage in Blue-Green Cities
Water 2017, 9(12), 953; doi:10.3390/w9120953
Received: 4 October 2017 / Revised: 27 November 2017 / Accepted: 4 December 2017 / Published: 7 December 2017
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Abstract
Urban drainage systems that incorporate elements of green infrastructure (SuDS/GI) are central features in Blue-Green and Sponge Cities. Such approaches provide effective control of stormwater management whilst generating a range of other benefits. However these benefits often occur coincidentally and are not developed
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Urban drainage systems that incorporate elements of green infrastructure (SuDS/GI) are central features in Blue-Green and Sponge Cities. Such approaches provide effective control of stormwater management whilst generating a range of other benefits. However these benefits often occur coincidentally and are not developed or maximised in the original design. Of all the benefits that may accrue, the relevant dominant benefits relating to specific locations and socio-environmental circumstances need to be established, so that flood management functions can be co-designed with these wider benefits to ensure both are achieved during system operation. The paper reviews a number of tools which can evaluate the multiple benefits of SuDS/GI interventions in a variety of ways and introduces new concepts of benefit intensity and benefit profile. Examples of how these concepts can be applied is provided in a case study of proposed SuDS/GI assets in the central area of Newcastle; UK. Ways in which SuDS/GI features can be actively extended to develop desired relevant dominant benefits are discussed; e.g., by (i) careful consideration of tree and vegetation planting to trap air pollution; (ii) extending linear SuDS systems such as swales to enhance urban connectivity of green space; and (iii) managing green roofs for the effective attenuation of noise or carbon sequestration. The paper concludes that more pro-active development of multiple benefits is possible through careful co-design to achieve the full extent of urban enhancement SuDS/GI schemes can offer. Full article
(This article belongs to the Special Issue Sponge Cities: Emerging Approaches, Challenges and Opportunities)
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Open AccessArticle Transient Modeling of Flow in Unsaturated Soils Using a Novel Collocation Meshless Method
Water 2017, 9(12), 954; doi:10.3390/w9120954
Received: 1 November 2017 / Revised: 1 December 2017 / Accepted: 4 December 2017 / Published: 7 December 2017
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Abstract
In this paper, a novel meshless method for the transient modeling of subsurface flow in unsaturated soils was developed. A linearization process for the nonlinear Richards equation using the Gardner exponential model to analyze the transient flow in the unsaturated zone was adopted.
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In this paper, a novel meshless method for the transient modeling of subsurface flow in unsaturated soils was developed. A linearization process for the nonlinear Richards equation using the Gardner exponential model to analyze the transient flow in the unsaturated zone was adopted. For the transient modeling, we proposed a pioneering work using the collocation Trefftz method and utilized the coordinate system in Minkowski spacetime instead of that in the original Euclidean space. The initial value problem for transient modeling of subsurface flow in unsaturated soils can then be transformed into the inverse boundary value problem. A numerical solution obtained in the spacetime coordinate system was approximated by superpositioning Trefftz basis functions satisfying the governing equation for boundary collocation points on partial problem domain boundary in the spacetime coordinate system. As a result, the transient problems can be solved without using the traditional time-marching scheme. The validity of the proposed method is established for several test problems. Numerical results demonstrate that the proposed method is highly accurate and computationally efficient. The results also reveal that it has great numerical stability for the transient modeling of subsurface flow in unsaturated soils. Full article
(This article belongs to the Special Issue Soil Water Conservation: Dynamics and Impact)
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Open AccessArticle Influence of Extreme Strength in Water Quality of the Jucazinho Reservoir, Northeastern Brazil, PE
Water 2017, 9(12), 955; doi:10.3390/w9120955
Received: 28 August 2017 / Revised: 22 November 2017 / Accepted: 27 November 2017 / Published: 7 December 2017
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Abstract
The Jucazinho reservoir was built in the State of Pernambuco, Northeastern Brazil, to water supply in a great part of the population that live in the semi-arid of Pernambuco. This reservoir controls the high part of Capibaribe river basin, area affected several actions
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The Jucazinho reservoir was built in the State of Pernambuco, Northeastern Brazil, to water supply in a great part of the population that live in the semi-arid of Pernambuco. This reservoir controls the high part of Capibaribe river basin, area affected several actions that can compromise the reservoir water quality such as disposal of domestic sewage, industrial wastewater and agriculture with use of fertilizers. This study aimed to identify the factors that lead to water quality of the Jucazinho reservoir using a database containing information of nine years of reservoir water quality monitoring in line with a multivariate statistical technique known as Principal Component Analysis (PCA). To use this technique, it was selected two components which determine the quality of the reservoir water. The first principal component, ranging from an annual basis, explained the relationship between the development of cyanobacteria, the concentration of dissolved solids and electrical conductivity, comparing it with the variation in the dam volume, total phosphorus levels and turbidity. The second principal component, ranging from a mensal basis, explained the photosynthetic activity performed by cyanobacteria confronting with the variation in the dam volume. It observed the relationship between water quality parameters with rainfall, featuring an annual and seasonal pattern that can be used as reference to behaviour studies of this reservoir. Full article
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Open AccessArticle Characteristics of Bacterial Communities in Cyanobacteria-Blooming Aquaculture Wastewater Influenced by the Phytoremediation with Water Hyacinth
Water 2017, 9(12), 956; doi:10.3390/w9120956
Received: 14 September 2017 / Revised: 26 November 2017 / Accepted: 1 December 2017 / Published: 7 December 2017
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Abstract
Cyanobacterial blooms often occur in aquaculture wastewater in China. A floating plant, water hyacinth has been widely used to treat this wastewater. Little is known, however, about bacterial community characteristics and the risk of potential pathogens in cyanobacteria-blooming aquaculture wastewater remediated by water
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Cyanobacterial blooms often occur in aquaculture wastewater in China. A floating plant, water hyacinth has been widely used to treat this wastewater. Little is known, however, about bacterial community characteristics and the risk of potential pathogens in cyanobacteria-blooming aquaculture wastewater remediated by water hyacinth. In wastewater treated with water hyacinth, we used culture enumeration and high-throughput sequencing to explore the characteristics of bacterial communities, the status of coliform bacteria, and pathogenic bacteria potentially conducive to human disease. Our results indicated that the relative abundance of Acidobacteria, Planctomycetes, Actinobacteria, Chlorobi, Cyanobacteria, Proteobacteria, and phylum OD1 in cyanobacteria-blooming aquaculture wastewater were significantly influenced by water hyacinth. After 30 days, the relative abundance of Proteobacteria and phylum OD1 in the water hyacinth treatments increased remarkably, while the relative abundance of the other 5 phyla in treatment was significantly reduced compared with the controls. In 21 major families, the relative abundance of Comamonadaceae, Oxalobacteraceae, Rhodocylclaceae, and an unnamed group from phylum OD1 increased significantly in the water hyacinth treatments compared with the controls. The number of total coliforms in wastewater treated by water hyacinth was significantly elevated and higher than controls during the first 6–18 days, with the maximum reaching 23,800 MPN/L. The level of potential pathogenic bacteria in wastewater treated by water hyacinth significantly reduced compared with the controls after 18 days, but it significantly increased from the initial level. It appears that water hyacinth by itself is not an effective treatment for reducing potential pathogens in aquaculture water. Full article
(This article belongs to the Special Issue Biological Treatment of Wastewater)
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Open AccessArticle Impacts of Climate Change and Human Activities on the Three Gorges Reservoir Inflow
Water 2017, 9(12), 957; doi:10.3390/w9120957
Received: 10 November 2017 / Revised: 1 December 2017 / Accepted: 4 December 2017 / Published: 7 December 2017
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Abstract
Identifying changes in runoff and quantifying the impacts of climate change and human activities are of great significance for water resources planning and management in a river basin. In this study, an inflow series of the Three Gorges Reservoir observed from 1951 to
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Identifying changes in runoff and quantifying the impacts of climate change and human activities are of great significance for water resources planning and management in a river basin. In this study, an inflow series of the Three Gorges Reservoir observed from 1951 to 2016 is used to identify the trend and abrupt change point by using statistical methods. Based on the meteorological data, soil type data, and land use data during the same period, the Soil and Water Assessment Tool (SWAT) model is established to quantitatively attribute changes in the Three Gorges Reservoir inflow to climate change and human activities separately and discuss the differences between the two-stage method, which divides the whole study period into two stages to analyze the reasons for runoff evolution, and multi-stage method, which divides the whole study period into more stages to consider the temporal and spatial variation of land use/cover (LULC). The results show: (1) During the study period, a significant decrease is detected in the Three Gorges Reservoir inflow and the decrease rate is 7.7 km3 per ten years, annual total precipitation decreases by −13.5 mm per ten years, and annual average temperature increases by 0.1 °C per ten years. (2) Contribution of climate change and human activities is around 7:3. Climate change is the main reason for the decrease in the Three Gorges Reservoir inflow. (3) Results of stages in multi-stage method are different from the result of two-stage method. Accumulative results of multi-stage method and result of two-stage method are consistent. There are some changes in results of every stage, which are different from the accumulative results. Full article
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Open AccessArticle A Participatory Approach for Adapting River Basins to Climate Change
Water 2017, 9(12), 958; doi:10.3390/w9120958
Received: 16 June 2017 / Revised: 1 December 2017 / Accepted: 5 December 2017 / Published: 8 December 2017
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Abstract
Climate change is expected to reduce water availability in the Mediterranean region and water management needs to adapt to future conditions. The aims of this study were (1) to develop a participatory approach for identifying and evaluating management options for river basin climate
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Climate change is expected to reduce water availability in the Mediterranean region and water management needs to adapt to future conditions. The aims of this study were (1) to develop a participatory approach for identifying and evaluating management options for river basin climate adaptation and (2) to apply and evaluate the approach in four case-study river basins across the Mediterranean. As part of the approach, a diverse group of stakeholders joined a series of workshops and consultations in four river basins located in Cyprus, Slovenia, Spain and Tunisia. In each river basin, stakeholders expressed their views on challenges in their river basins, as well as options to tackle these challenges. We used the information on challenges, as well as the factors contributing to these challenges to develop a fuzzy cognitive map for each basin. These maps were converted into mathematical models and were used to assess the impact of a total of 102 suggested management options for the four river basins. We linked the options and their estimated impacts with a multi-criteria analysis to identify the most preferred options. The approach was positively evaluated by the participating stakeholders and allowed the link of stakeholders’ knowledge and perceptions about their river basin with their preferences for options to adapt the management of their river basins to future conditions. Full article
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Open AccessArticle A Natural Analogue Approach for Discriminating Leaks of CO2 Stored Underground Using Groundwater Geochemistry Statistical Methods, South Korea
Water 2017, 9(12), 960; doi:10.3390/w9120960
Received: 8 October 2017 / Revised: 2 December 2017 / Accepted: 2 December 2017 / Published: 8 December 2017
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Abstract
Carbon capture and storage (CCS) is one of several useful strategies for capturing greenhouse gases to counter global climate change. In CCS, greenhouse gases such as CO2 that are emitted from stacks are isolated in underground geological storage. Natural analogue studies that
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Carbon capture and storage (CCS) is one of several useful strategies for capturing greenhouse gases to counter global climate change. In CCS, greenhouse gases such as CO2 that are emitted from stacks are isolated in underground geological storage. Natural analogue studies that can provide insights into possible geological CO2 storage sites, can deliver crucial information about the safety and security of geological sequestration, the long-term impact of CO2 storage on the environment, and the field operation and monitoring requirements for geological sequestration. This study adopted a probability density function (PDF) approach for CO2 leakage monitoring by characterizing naturally occurring CO2-rich groundwater as an analogue that can occur around a CO2 storage site due to CO2 dissolving into fresh groundwater. Two quantitative indices, (QItail and QIshift), were estimated from the PDF test and were used to compare CO2-rich and ordinary groundwaters. Key geochemical parameters (pH, electrical conductance, total dissolved solids, HCO3, Ca2+, Mg2+, and SiO2) in different geological regions of South Korea were determined through a comparison of quantitative indices and the respective distribution patterns of the CO2-rich and ordinary groundwaters. Full article
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Open AccessArticle Exploring Numerically the Benefits of Water Discharge Prediction for the Remote RTC of WDNs
Water 2017, 9(12), 961; doi:10.3390/w9120961
Received: 20 October 2017 / Revised: 6 December 2017 / Accepted: 7 December 2017 / Published: 9 December 2017
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Abstract
This paper explores numerically the benefits of water discharge prediction in the real time control (RTC) of water distribution networks (WDNs). An algorithm aimed at controlling the settings of control valves and variable speed pumps, as a function of pressure head signals from
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This paper explores numerically the benefits of water discharge prediction in the real time control (RTC) of water distribution networks (WDNs). An algorithm aimed at controlling the settings of control valves and variable speed pumps, as a function of pressure head signals from remote nodes in the network, is used. Two variants of the algorithm are considered, based on the measured water discharge in the device at the current time and on the prediction of this variable at the new time, respectively. As a result of the prediction, carried out using a polynomial with coefficients determined through linear regression, the RTC algorithm attempts to correct the expected deviation of the controlled pressure head from the set point, rather than the currently measured deviation. The applications concerned the numerical simulation of RTC in a WDN, in which the nodal demands are reconstructed stochastically through the bottom-up approach. The results prove that RTC benefits from the implementation of the prediction, in terms of the closeness of the controlled variable to the set point and of total variations of the device setting. The benefits are more evident when the water discharge features contained random fluctuations and large hourly variations. Full article
(This article belongs to the Special Issue Advances in Water Distribution Networks)
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Open AccessFeature PaperArticle UV Disinfection of Hand-Rinse Greywater and Performance Testing Using Indigenous Staphylococcus spp.
Water 2017, 9(12), 963; doi:10.3390/w9120963
Received: 1 November 2017 / Revised: 4 December 2017 / Accepted: 8 December 2017 / Published: 11 December 2017
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Abstract
Greywater reuse is a feasible solution for decreasing raw water extraction in urban and rural settings. However, pathogen-specific performance guidelines and regulations have only recently been recommended; practical means to assess performance are missing. Here we examine the efficacy of Staphylococcus spp. as
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Greywater reuse is a feasible solution for decreasing raw water extraction in urban and rural settings. However, pathogen-specific performance guidelines and regulations have only recently been recommended; practical means to assess performance are missing. Here we examine the efficacy of Staphylococcus spp. as an endogenous surrogate for greywater pathogen reduction performance testing, by evaluating UV-C irradiation of hand-rinse greywater, and the variability in UV resistance between different wild Staphylococcus species. Hand-rinse greywater samples were collected from five participants, and a collimated UV-C beam (256 nm) was used to assess log10 reductions. Assays of colony-forming units on tryptic soy agar (TSA) were compared to mannitol salt agar (MSA) using LysostaphinTM to confirm Staphylococcus spp. After irradiating raw hand-rinse samples to a dose of 220 mJ·cm−2, log10 reductions of Staphylococcus spp. were similar (2.1 and 2.2, respectively, p = 0.112). The similarity of the reduction based on TSA and Staphylococcus-specific culture assays following UV irradiation and the dominating presence of Staphylococcus spp. suggests that Staphylococcus spp. could be used as an endogenous performance surrogate group for greywater treatment testing. Suspended wild Staphylococcus isolates were irradiated with 256 nm UV-C to compare the variability of different Staphylococcus species. Staphylococcus isolates exhibited significant variance in log10 reduction values when exposed to 11 mJ·cm−2 of UV-C. Staphylococcus hominis subsp. hominis exhibited surprising resistance to UV-C, with only a 1.6-log10 reduction when exposed to 11 mJ·cm−2 of UV-C (most other isolates exhibited > 5-log10 reduction). The efficacy of UV-C was also significantly reduced when the sunscreen oxybenzone was present at a possible endogenous greywater concentration. Full article
(This article belongs to the Special Issue Development of Alternative Water Sources in the Urban Sector)
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Open AccessFeature PaperArticle Spanish Agriculture and Water: Educational Implications of Water Culture and Consumption from the Farmers’ Perspective
Water 2017, 9(12), 964; doi:10.3390/w9120964
Received: 14 October 2017 / Revised: 6 November 2017 / Accepted: 6 December 2017 / Published: 11 December 2017
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Abstract
The responsible management and consumption of water is a challenge that involves all segments of society. Having access to sufficient quality and quantity of water is not only a technological issue, but requires that the adopted measures and programmes take into account the
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The responsible management and consumption of water is a challenge that involves all segments of society. Having access to sufficient quality and quantity of water is not only a technological issue, but requires that the adopted measures and programmes take into account the dimensions of society and education. Spanish agriculture, as in other areas of the world, is a major consumer of water and more so than other sectors, including household consumption. Within the field of environmental education, this study covered the water culture and consumption of Andalusian farmers, based on their own perceptions. For this purpose, a questionnaire was created and validated, and included a sample of 1030 farmers selected with pseudorandom number sampling. An analysis of the data showed relevant results with respect to the values and notions supporting the justification for farmer behaviours, both from a cognitive-representative viewpoint and from an affective-expressive stance, as well as assertions made by the irrigators about other key sectors concerning the responsible management of water usage and water consumption. The findings of this study may assist in the design of environmental education programmes addressing this sector, which could also include other similar populations. Full article
(This article belongs to the Special Issue Recent Advances in Water Management: Saving, Treatment and Reuse)
Open AccessArticle Spatial and Temporal Variations of Snow Cover in the Karoon River Basin, Iran, 2003–2015
Water 2017, 9(12), 965; doi:10.3390/w9120965
Received: 25 September 2017 / Revised: 17 November 2017 / Accepted: 6 December 2017 / Published: 11 December 2017
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Abstract
The Karoon River Basin, with an area of about 67,000 km2, is located in the southern part of Iran and has a complex mountainous terrain. No comprehensive study has been done on the spatial and temporal variations of snow cover in
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The Karoon River Basin, with an area of about 67,000 km2, is located in the southern part of Iran and has a complex mountainous terrain. No comprehensive study has been done on the spatial and temporal variations of snow cover in this region to date. In this paper, daily snow data of Moderate Resolution Imaging Spectroradiometer MODIS Terra (MOD10A1) and MODIS Aqua (MYD10A1) were examined from 1 January 2003 to 31 December 2015, to analyze snow cover variations. Due to difficulties created by cloud cover effects, it was crucial to reduce cloud contamination in the daily time series. Therefore, two common cloud removal methods were applied on the daily data. The results suggested that in winter nearly 43% of the Basin’s area experienced a negative trend, while only 1.4% of the Basin had a positive trend for snow-covered days (SCD); trends in fall and spring were less evident in the data. Using a digital elevation model of the Basin, the trends of SCD in 100 m elevation intervals were calculated, indicating a significant positive trend in SCD during the fall season above 3500 m. Full article
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Open AccessArticle Climate Change Impacts on Flow and Suspended Sediment Yield in Headwaters of High-Latitude Regions—A Case Study in China’s Far Northeast
Water 2017, 9(12), 966; doi:10.3390/w9120966
Received: 10 October 2017 / Revised: 15 November 2017 / Accepted: 7 December 2017 / Published: 11 December 2017
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Abstract
Climate change is expected to have stronger effects on water resources in higher latitude regions. Despite intensive research on possible hydrological responses in those regions to a warmer environment, our knowledge on erosion and sediment yield induced by the climate change in high-latitude
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Climate change is expected to have stronger effects on water resources in higher latitude regions. Despite intensive research on possible hydrological responses in those regions to a warmer environment, our knowledge on erosion and sediment yield induced by the climate change in high-latitude headwaters is still limited. In this study, we estimated suspended sediment yields from 2021 to 2050 in a typical headwater area of far Northeast China to elucidate potential impacts of future climate change on surface runoff and erosion in higher latitude regions. We first parameterized the Soil and Water Assessment Tool (SWAT) using historical measurements to estimate runoff from the river basin. The model performed well in both the calibration (2006–2011) and the validation (2012–2014) periods, with an R2 of 0.85 and 0.88 and a Nash-Sutcliffe Efficiency (NSE) of 0.7 and 0.73, respectively. We also utilized historical measurements on sediment yields from the period 2006–2014 to develop a runoff-sediment yield rating curve, and the rating curve obtained an excellent goodness of fit (R2 = 0.91, p < 0.001). We then applied the calibrated SWAT model to two climate change projections, also known as Representative Concentration Pathways (RCP4.5 and RCP8.5), for the period from 2021 to 2050 to obtain future runoff estimates. These runoff estimates were then used to predict future sediment yield by using the developed runoff-sediment yield rating curve. Our study found a significant increase of annual sediment yield (p < 0.05) for both climate change projections (RCP4.5 = 237%; RCP8.5 = 133%) in this, China’s high-latitude region. The increases of sediment yield were prevalent in summer and autumn, varying from 102–299% between the two RCPs scenarios. Precipitation was the dominated factor that determined the variation of runoff and sediment yield. A warming climate could bring more snowmelt-induced spring runoff and longer rainy days in autumn, hence leading to higher erosion. These findings demonstrate that under the changing climate, soils in this high-latitude headwater area would be eroded twice to three times that of the baseline period (1981–2010), indicating a potential risk to the downstream water quality and reservoir management. Full article
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Open AccessArticle To What Extent Are Swiss Springs Refugial Habitats for Sensitive and Endangered Diatom Taxa?
Water 2017, 9(12), 967; doi:10.3390/w9120967
Received: 30 September 2017 / Revised: 20 November 2017 / Accepted: 9 December 2017 / Published: 12 December 2017
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Abstract
Habitat alteration is one of the major drivers of species loss. Springs may be among the least affected aquatic habitats and are considered to be refugial habitats. Diatom assemblages were sampled from 74 Swiss springs comprising seven spring types over a wide altitudinal
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Habitat alteration is one of the major drivers of species loss. Springs may be among the least affected aquatic habitats and are considered to be refugial habitats. Diatom assemblages were sampled from 74 Swiss springs comprising seven spring types over a wide altitudinal and ecological range as well as a wide range of anthropogenic modifications (alterations). Each spring was assigned to a five-point alteration scale, from natural to heavily altered. In total, 504 diatom species were recorded (not including 36 taxa that could not be identified to species level) from five microhabitats, and coded according to rarity and Red List status. The results of this extensive spring-habitat diatom survey were compared statistically with a large stream diatom dataset (DI-CH). The spring diatom microflora was more species rich and included more rare and/or threatened species than the stream microflora. The proportion of Red List species and rare species was highest in the DI-CH dataset, but the proportion of species with no Red List status and rare species was the highest in springs. Species richness, Red List status, and rarity were significantly related to the degree of spring alteration. This is consistent with the hypothesis that unaltered springs function as refuges for the Swiss fresh water microflora, and that they can be regarded as “least-impaired habitats”. These may be critically important for the conservation of the European freshwater diatom microflora. Full article
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Open AccessArticle Detoxification of Pesticide-Containing Wastewater with FeIII, Activated Carbon and Fenton Reagent and Its Control Using Three Standardized Bacterial Inhibition Tests
Water 2017, 9(12), 969; doi:10.3390/w9120969
Received: 9 November 2017 / Revised: 7 December 2017 / Accepted: 8 December 2017 / Published: 12 December 2017
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Abstract
Discharge of toxic industrial wastewaters into biological wastewater treatment plants may result in inhibition of activated sludge bacteria (ASB). In order to find an appropriate method of detoxification, the wastewater of a pesticide-processing plant in Vietnam was treated with three different methods (Fe
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Discharge of toxic industrial wastewaters into biological wastewater treatment plants may result in inhibition of activated sludge bacteria (ASB). In order to find an appropriate method of detoxification, the wastewater of a pesticide-processing plant in Vietnam was treated with three different methods (FeIII, powdered activated carbon (PAC), Fenton (FeII/H2O2)) analyzing the detoxification effect with the nitrification inhibition test (NIT), respiration inhibition test (RIT) and luminescent bacteria test (LBT). The heterotrophic ASB were much more resistant to the wastewater than the autotrophic nitrificants. The NIT turned out to be more suitable than the RIT since the NIT was less time-consuming and more reliable. In addition, the marine Aliivibrio fischeri were more sensitive than the nitrificants indicating that a lack of inhibition in the very practical and time-efficient LBT correlates with a lack of nitrification inhibition. With 95%, the Fenton method showed the highest efficiency regarding the chemical oxygen demand (COD) removal. Although similar COD removal (60–65%) was found for both the FeIII and the PAC method, the inhibitory effect of the wastewater was reduced much more strongly with PAC. Both the NIT and the LBT showed that the PAC and Fenton methods led to a similar reduction in the inhibitory effect. Full article
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Open AccessArticle Treatment of Rural Wastewater Using a Spiral Fiber Based Salinity-Persistent Sequencing Batch Biofilm Reactor
Water 2017, 9(12), 970; doi:10.3390/w9120970
Received: 13 October 2017 / Revised: 5 November 2017 / Accepted: 8 December 2017 / Published: 12 December 2017
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Abstract
Differing from municipal wastewater, rural wastewater in salinization areas is characterized with arbitrary discharge and high concentration of salt, COD, nitrogen and phosphorus, which would cause severe deterioration of rivers and lakes. To overcome the limits of traditional biological processes, a spiral fiber
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Differing from municipal wastewater, rural wastewater in salinization areas is characterized with arbitrary discharge and high concentration of salt, COD, nitrogen and phosphorus, which would cause severe deterioration of rivers and lakes. To overcome the limits of traditional biological processes, a spiral fiber based salinity-persistent Sequencing Biofilm Batch Reactor (SBBR) was developed and investigated with synthetic rural wastewater (COD = 500 mg/L, NH4+-N = 50 mg/L, TP = 6 mg/L) under different salinity (0.0–10.0 g/L of NaCl). Results indicated that a quick start-up could be achieved in 15 days, along with sufficient biomass up to 7275 mg/L. During operating period, the removal of COD, NH4+-N, TN was almost not disturbed by salt varying from 0.0 to 10.0 g/L with stable efficiency reaching 92%, 82% and 80%, respectively. Although TP could be removed at high efficiency of 90% in low salinity conditions (from 0.0 to 5.0 g/L of NaCl), it was seriously inhibited due to nitrite accumulation and reduction of Phosphorus Accumulating Organisms (PAOs) after addition of 10.0 g/L of salt. The behavior proposed in this study will provide theoretical foundation and guidance for application of SBBR in saline rural wastewater treatment. Full article
(This article belongs to the Special Issue Biological Treatment of Wastewater)
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Open AccessArticle Changes in Pan Evaporation and Their Attribution to Climate Factors in the Zoige Alpine Wetland, the Eastern Edge of the Tibetan Plateau (1969–2014)
Water 2017, 9(12), 971; doi:10.3390/w9120971
Received: 20 October 2017 / Revised: 7 December 2017 / Accepted: 8 December 2017 / Published: 14 December 2017
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Abstract
Decreases in pan evaporation (Epan) over the last decades have been reported in many regions of the world. In this study, changes of Epan in the Zoige Plateau alpine wetland (hereinafter referred to as “Zoige wetland”) and its peripheral
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Decreases in pan evaporation (Epan) over the last decades have been reported in many regions of the world. In this study, changes of Epan in the Zoige Plateau alpine wetland (hereinafter referred to as “Zoige wetland”) and its peripheral regions from 1969 to 2014 were investigated using the PenPan model based on the long-term meteorological data. The contribution of climate factors to Epan change were quantified by using partial derivatives of the PenPan model. Results indicated that Epan in Zoige wetland exhibited an obvious decreasing trend before 1989, but rapidly increased after 1990. The increase in Epan in the Zoige wetland is more significant than that in its peripheral regions and the entire Tibetan Plateau, which contributed to the more significant warming in the Zoige wetland. The pan evaporation in Zoige wetland after 1990 could be mostly attributed to changes in the aerodynamic component, and the decreasing radiation and wind speed is the primary contributor to the decline of pan evaporation during 1969–1989, while increasing air temperature and vapor pressure deficit were the major contributors to the increase of pan evaporation after 1990. Full article
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Open AccessArticle Water Gender Indicators in Agriculture: A Study of Horticultural Farmer Organizations in Senegal
Water 2017, 9(12), 972; doi:10.3390/w9120972
Received: 10 August 2017 / Revised: 9 November 2017 / Accepted: 6 December 2017 / Published: 13 December 2017
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Abstract
This paper intends to contribute to the debate on gender equality and water within the Sustainable Development Goals SDGs 5 and 6. Farmers organizations are often considered key stakeholders whose participation should be fostered to achieve a good water governance in agriculture and
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This paper intends to contribute to the debate on gender equality and water within the Sustainable Development Goals SDGs 5 and 6. Farmers organizations are often considered key stakeholders whose participation should be fostered to achieve a good water governance in agriculture and irrigation programs. Nonetheless, many water management interventions tackle participation as an instrumental and formal process. A common assumption is that granting sufficient space for women in water management will automatically ensure a greater gender empowerment. Nevertheless, often low importance is given to assessing who really actively participates and benefits from water development projects, favoring the technical aspects. This paper addresses the articulation between gender, water management and indicators, using male, female and mixed farmer organizations as touchstones in three regions of Senegal. The authors defines a system of water gender indicators grouped into five sections. The first results show more similarities between mixed and female organizations, while the main gender inequalities are visible in the water technique and economic domains. Thanks to this study, we can see how a gender-based analysis may allow to more deeply understand some more or less “hidden” water governance mechanisms and their related implications in terms of project management and policy making. Full article
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Open AccessArticle SPHysics Simulation of Experimental Spillway Hydraulics
Water 2017, 9(12), 973; doi:10.3390/w9120973 (registering DOI)
Received: 28 October 2017 / Revised: 9 December 2017 / Accepted: 11 December 2017 / Published: 14 December 2017
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Abstract
In this paper, we use the parallel open source code parallelSPHysics based on the weakly compressible Smoothed Particle Hydrodynamics (WCSPH) approach to study a spillway flow over stepped stairs. SPH is a robust mesh-free particle modelling technique and has great potential in treating
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In this paper, we use the parallel open source code parallelSPHysics based on the weakly compressible Smoothed Particle Hydrodynamics (WCSPH) approach to study a spillway flow over stepped stairs. SPH is a robust mesh-free particle modelling technique and has great potential in treating the free surfaces in spillway hydraulics. A laboratory experiment is carried out for the different flow discharges and spillway step geometries. The physical model is constructed from a prototype reservoir dam in the practical field. During the experiment, flow discharge over the weir crest, free surface, velocity and pressure profiles along the spillway are measured. In the present SPH study, a straightforward push-paddle model is used to generate the steady inflow discharge in front of the weir. The parallelSPHysics model is first validated by a documented benchmark case of skimming flow over a stepped spillway. Subsequently, it is used to reproduce a laboratory experiment based on a prototype hydraulic dam project located in Qinghai Province, China. The detailed comparisons are made on the pressure profiles on the steps between the SPH results and experimental data. The energy dissipation features of the flows under different flow conditions are also discussed. It is shown that the pressure on the horizontal face of the steps demonstrates an S-shape, while on the vertical face it is negative on the upper part and positive on the lower part. The energy dissipation efficiency of the spillway could reach nearly 80%. Full article
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Open AccessArticle Design and Modeling of an Adaptively Controlled Rainwater Harvesting System
Water 2017, 9(12), 974; doi:10.3390/w9120974
Received: 26 September 2017 / Revised: 28 November 2017 / Accepted: 7 December 2017 / Published: 14 December 2017
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Abstract
Management of urban stormwater to mitigate Combined Sewer Overflows (CSOs) is a priority for many cities; yet, few truly innovative approaches have been proposed to address the problem. Recent advances in information technology are now, however, providing cost-effective opportunities to achieve better performance
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Management of urban stormwater to mitigate Combined Sewer Overflows (CSOs) is a priority for many cities; yet, few truly innovative approaches have been proposed to address the problem. Recent advances in information technology are now, however, providing cost-effective opportunities to achieve better performance of conventional stormwater infrastructure through a Continuous Monitoring and Adaptive Control (CMAC) approach. The primary objective of this study was to demonstrate that a CMAC approach can be applied to a conventional rainwater harvesting system in New York City to improve performance by minimizing discharge to the combined sewer during rainfall events, reducing water use for irrigation of local vegetation, and optimizing vegetation health. To achieve this objective, a hydrologic and hydraulic model was developed for a planned and designed rainwater harvesting system to explore multiple potential scenarios prior to the system’s actual construction. Model results indicate that the CMAC rainwater harvesting system is expected to provide significant performance improvements over conventional rainwater harvesting systems. The CMAC system is expected to capture and retain 76.6% of roof runoff per year on average, as compared to just 14.8% and 41.3% for conventional moisture and timer based systems, respectively. Similarly, the CMAC system is expected to use 81.4% and 18.0% less harvested rainwater than conventional moisture and timer based irrigation approaches, respectively. The flexibility of the CMAC approach to meet competing objectives is promising for widespread implementation in New York City and other heavily urbanized areas challenged by stormwater management issues. Full article
(This article belongs to the Special Issue Advances on Urban Stormwater Harvesting Strategies)
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Open AccessArticle Water Experts’ Perception of Risk for New and Unfamiliar Water Projects
Water 2017, 9(12), 976; doi:10.3390/w9120976 (registering DOI)
Received: 31 October 2017 / Revised: 29 November 2017 / Accepted: 12 December 2017 / Published: 15 December 2017
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Abstract
In the context of a changing urban environment and increasing demand due to population growth, alternative water sources must be explored in order to create future water security. Risk assessments play a pivotal role in the take-up of new and unfamiliar water projects,
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In the context of a changing urban environment and increasing demand due to population growth, alternative water sources must be explored in order to create future water security. Risk assessments play a pivotal role in the take-up of new and unfamiliar water projects, acting as a decision-making tool for business cases. Perceptions of risk ultimately drive risk assessment processes, therefore providing insight into understanding projects that proceed and those that do not. Yet there is limited information on the risk perceptions water professionals have of new and unfamiliar water projects. In this study, 77 water professionals were surveyed from across the Melbourne metropolitan water industry to examine risk perceptions over a range of different, unfamiliar water projects. The qualitative data was thematically analysed, resulting in a number of risk perception factors for each hypothetical project. Risk factors that recurred most frequently are those that relate to community backlash and to the reputation of the organisation. These social risk perceptions occurred more frequently than other more technical risks, such as operational risks and process-related risks. These results were at odds with the existing literature assessing risk perceptions of business-as-usual projects, which presented cost as the key risk attribute. This study sheds light on the perceived nature of new and unfamiliar processes in the water sector, providing an understanding that public perceptions do matter to experts involved in water infrastructure decision-making. Full article
(This article belongs to the Special Issue Urban Water Cycle Modelling and Management)
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Open AccessArticle Water Use and Conservation on a Free-Stall Dairy Farm
Water 2017, 9(12), 977; doi:10.3390/w9120977 (registering DOI)
Received: 13 October 2017 / Revised: 6 December 2017 / Accepted: 8 December 2017 / Published: 15 December 2017
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Abstract
Livestock watering can represent as much as 20% of total agricultural water use in areas with intensive dairy farming. Due to an increased emphasis on water conservation for the agricultural sector, it is important to understand the current patterns of on-farm water use.
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Livestock watering can represent as much as 20% of total agricultural water use in areas with intensive dairy farming. Due to an increased emphasis on water conservation for the agricultural sector, it is important to understand the current patterns of on-farm water use. This study utilized in situ water meters to measure the year-round on-farm pumped water (i.e., blue water) on a ~419 lactating cow confined dairy operation in Eastern Ontario, Canada. The average total water use for the farm was 90,253 ± 15,203 L day−1 and 33,032 m3 annually. Water use was divided into nutritional water (68%), parlour cleaning and operation (14%), milk pre-cooling (15%), barn cleaning, misters and other uses (3%). There was a positive correlation between total monthly water consumption (i.e., nutritional water) and average monthly temperature for lactating cows, heifers, and calves (R2 = 0.69, 0.84, and 0.85, respectively). The blue water footprint scaled by milk production was 6.19 L kg−1 milk or 6.41 L kg−1 fat-and-protein corrected milk (FPCM) including contributions from all animal groups and 5.34 L kg−1 milk (5.54 L kg−1 FPCM) when excluding the water consumption of non-lactating animals. By applying theoretical water conservation scenarios we show that a combination of strategies (air temperature reduction, complete recycling of milk-cooling water, and modified cow preparation protocol) could achieve a savings of 6229 m3 annually, a ~19% reduction in the total annual water use. Full article
(This article belongs to the Special Issue Recent Advances in Water Management: Saving, Treatment and Reuse)
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Review

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Open AccessReview A Review of Ocean/Sea Subsurface Water Temperature Studies from Remote Sensing and Non-Remote Sensing Methods
Water 2017, 9(12), 936; doi:10.3390/w9120936 (registering DOI)
Received: 3 October 2017 / Revised: 13 November 2017 / Accepted: 16 November 2017 / Published: 14 December 2017
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Abstract
Oceans/Seas are important components of Earth that are affected by global warming and climate change. Recent studies have indicated that the deeper oceans are responsible for climate variability by changing the Earth’s ecosystem; therefore, assessing them has become more important. Remote sensing can
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Oceans/Seas are important components of Earth that are affected by global warming and climate change. Recent studies have indicated that the deeper oceans are responsible for climate variability by changing the Earth’s ecosystem; therefore, assessing them has become more important. Remote sensing can provide sea surface data at high spatial/temporal resolution and with large spatial coverage, which allows for remarkable discoveries in the ocean sciences. The deep layers of the ocean/sea, however, cannot be directly detected by satellite remote sensors. Therefore, researchers have examined the relationships between salinity, height, and temperature of the oceans/Seas to estimate their subsurface water temperature using dynamical models and model-based data assimilation (numerical based and statistical) approaches, which simulate these parameters by employing remotely sensed data and in situ measurements. Due to the requirements of comprehensive perception and the importance of global warming in decision making and scientific studies, this review provides comprehensive information on the methods that are used to estimate ocean/sea subsurface water temperature from remotely and non-remotely sensed data. To clarify the subsurface processes, the challenges, limitations, and perspectives of the existing methods are also investigated. Full article
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Other

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Open AccessTechnical Note Comparisons of Different Instruments for Measuring Suspended Cohesive Sediment Concentrations
Water 2017, 9(12), 968; doi:10.3390/w9120968
Received: 17 October 2017 / Revised: 8 December 2017 / Accepted: 8 December 2017 / Published: 12 December 2017
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Abstract
Laboratory experiments were conducted to compare the performances of four different instruments for measuring suspended cohesive sediment concentrations (SSCs). Among these instruments, two were different models of optical backscatter sensor (i.e., OBS3+ and OBS5+), one was an acoustic Doppler velocimeter (MicroADV), and the
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Laboratory experiments were conducted to compare the performances of four different instruments for measuring suspended cohesive sediment concentrations (SSCs). Among these instruments, two were different models of optical backscatter sensor (i.e., OBS3+ and OBS5+), one was an acoustic Doppler velocimeter (MicroADV), and the last was a laser infrared optical sensor developed at Hohai University, China (HHU-LIOS). Sediments collected from the Yangtze River Estuary and a commercially available kaolinite were selected to check the responses of these four instruments. They were placed in an aqueous solution, and the SSCs were changed within a range from about 10 mg/L to 30 g/L to demonstrate the effective measuring ranges for each instrument. For the kaolinite suspension, the results showed that the HHU-LIOS has a much larger linear response range (0.1 to 13 g/L) when compared with other devices (the MicroADV: 0.1 to 1.35 g/L; the OBS3+: 0.1 to 5 g/L; and the OBS5+: 0.1 to 1 g/L). For the sediment sample from the Yangtze River Estuary, the results showed that the HHU-LIOS has a much wider usable range (from 0.1 to 25 g/L), compared with those for the others. It also showed that a combination of using a HHU-LIOS for the quadratic increasing range up to 25 g/L and the OBS5+ for the clear decreasing output are able to measure the SSCs of the estuarine mud up to 50 g/L. Full article
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