Water

674 KiB

Open AccessArticle

Suitability of a Coupled Hydrodynamic Water Quality Model to Predict Changes in Water Quality from Altered Meteorological Boundary Conditions

by Leon Van der Linden, Robert I. Daly and Mike D. Burch

Water 2015, 7(1), 348-361; https://doi.org/10.3390/w7010348 - 20 Jan 2015

Cited by 7 | Viewed by 6106

Abstract

Downscaled climate scenarios can be used to inform management decisions on investment in infrastructure or alternative water sources within water supply systems. Appropriate models of the system components, such as catchments, rivers, lakes and reservoirs, are required. The climatic sensitivity of the coupled [...] Read more.

Downscaled climate scenarios can be used to inform management decisions on investment in infrastructure or alternative water sources within water supply systems. Appropriate models of the system components, such as catchments, rivers, lakes and reservoirs, are required. The climatic sensitivity of the coupled hydrodynamic water quality model ELCOM-CAEDYM was investigated, by incrementally altering boundary conditions, to determine its suitability for evaluating climate change impacts. A series of simulations were run with altered boundary condition inputs for the reservoir. Air and inflowing water temperature (TEMP), wind speed (WIND) and reservoir inflow and outflow volumes (FLOW) were altered to investigate the sensitivity of these key drivers over relevant domains. The simulated water quality variables responded in broadly plausible ways to the altered boundary conditions; sensitivity of the simulated cyanobacteria population to increases in temperature was similar to published values. However the negative response of total chlorophyll-a suggested by the model was not supported by an empirical analysis of climatic sensitivity. This study demonstrated that ELCOM-CAEDYM is sensitive to climate drivers and may be suitable for use in climate impact studies. It is recommended that the influence of structural and parameter derived uncertainty on the results be evaluated. Important factors in determining phytoplankton growth were identified and the importance of inflowing water quality was emphasized. Full article

(This article belongs to the Special Issue Water Resources in a Variable and Changing Climate)

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1137 KiB

Open AccessArticle

Effectiveness of Domestic Wastewater Treatment Using a Bio-Hedge Water Hyacinth Wetland System

by Alireza Valipour, Venkatraman Kalyan Raman and Young-Ho Ahn

Water 2015, 7(1), 329-347; https://doi.org/10.3390/w7010329 - 19 Jan 2015

Cited by 81 | Viewed by 19366

Abstract

onstructed wetland applications have been limited by a large land requirement and capital investment. This study aimed to improve a shallow pond water hyacinth system by incorporating the advantages of engineered attached microbial growth technique (termed Bio-hedge) for on-site domestic wastewater treatment. A [...] Read more.

onstructed wetland applications have been limited by a large land requirement and capital investment. This study aimed to improve a shallow pond water hyacinth system by incorporating the advantages of engineered attached microbial growth technique (termed Bio-hedge) for on-site domestic wastewater treatment. A laboratory scale continuous-flow system consists of the mesh type matrix providing an additional biofilm surface area of 54 m²/m³. Following one year of experimentation, the process showed more stability and enhanced performance in removing organic matter and nutrients, compared to traditional water hyacinth (by lowering 33%–67% HRT) and facultative (by lowering 92%–96% HRT) ponds. The wastewater exposed plants revealed a relative growth rate of 1.15% per day, and no anatomical deformities were observed. Plant nutrient level averaged 27 ± 1.7 and 44 ± 2.3 mg N/g dry weight, and 5 ± 1.4 & 9±1.2 mg P/g dry weight in roots and shoots, respectively. Microorganisms immobilized on Bio-hedge media (4.06 × 10⁷cfu/cm²) and plant roots (3.12 × 10⁴cfu/cm) were isolated and identified (a total of 23 strains). The capital cost was pre-estimated for 1 m³/d wastewater at 78 US$/m³_inflow and 465 US$/kg BOD_{5 removed}. This process is a suitable ecotechnology due to improved biofilm formation, reduced footprint, energy savings, and increased quality effluent. Full article

(This article belongs to the Special Issue Advances in On-Site Wastewater Treatment and Technologies to Characterize the Fate and Transport of Wastewater Constituents)

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589 KiB

Open AccessArticle

Stakeholder Views, Financing and Policy Implications for Reuse of Wastewater for Irrigation: A Case from Hyderabad, India

by Markus Starkl, Norbert Brunner, Priyanie Amerasinghe, Jampani Mahesh, Dinesh Kumar, Shyam R. Asolekar, Sahebrao Sonkamble, Shakeel Ahmed, Mohammed Wajihuddin, Adepu Pratyusha and Sarah Sarah

Water 2015, 7(1), 300-328; https://doi.org/10.3390/w7010300 - 19 Jan 2015

Cited by 26 | Viewed by 10011

Abstract

When flowing through Hyderabad, the capital of Telangana, India, the Musi River picks up (partially) treated and untreated sewage from the city. Downstream of the city, farmers use this water for the irrigation of rice and vegetables. Treatment of the river water before [...] Read more.

When flowing through Hyderabad, the capital of Telangana, India, the Musi River picks up (partially) treated and untreated sewage from the city. Downstream of the city, farmers use this water for the irrigation of rice and vegetables. Treatment of the river water before it is used for irrigation would address the resulting risks for health and the environment. To keep the costs and operational efforts low for the farmers, the use of constructed wetlands is viewed as a suitable option. Towards this end, the paper investigates the interests and perceptions of government stakeholders and famers on the treatment of wastewater for irrigation and further explores the consumer willingness to pay a higher price for cleaner produced vegetables. Full cost recovery from farmers and consumers cannot be expected, if mass scale treatment of irrigation water is implemented. Instead, both consumers and farmers would expect that the government supports treatment of irrigation water. Most stakeholders associated with the government weigh health and environment so high, that these criteria outweigh cost concerns. They also support the banning of irrigation with polluted water. However, fining farmers for using untreated river water would penalize them for pollution caused by others. Therefore public funding of irrigation water treatment is recommended. Full article

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299 KiB

Open AccessArticle

Carbon Turnover during Effluent Application to the Land: A Potential Role for Vegetation?

by Vasileios A. Tzanakakis, Giannis Vagiakis, Myrto Tsiknia, Andreas N. Angelakis and Nikolaos V. Paranychianakis

Water 2015, 7(1), 288-299; https://doi.org/10.3390/w7010288 - 13 Jan 2015

Cited by 1 | Viewed by 5352

Abstract

This work investigates the effect of plant species (Eucalyptus camaldulensis vs. Arundo donax) on carbon (C) turnover during wastewater application to the land. The study was carried out in 40-liter pots under field conditions and plant species were treated either with [...] Read more.

This work investigates the effect of plant species (Eucalyptus camaldulensis vs. Arundo donax) on carbon (C) turnover during wastewater application to the land. The study was carried out in 40-liter pots under field conditions and plant species were treated either with pre-treated municipal wastewater or freshwater. Plant species had a strong effect on soil organic matter with pots planted with E. camaldulensis showing greater values than pots planted with A. donax. In accordance, greater respiration rates were measured in E. camaldulensis pots compared to those planted with A. donax. The respiration rate followed a decreasing trend with the progress of the season for both species. These findings suggest differences in soil microbial community composition and/or activity in the rhizosphere of plant species. Minor effects of plant species or effluent were observed in dissolved organic carbon, protein, and hexoses content. In conclusion, the results of the present study reveal an important role of plant species on C cycling in terrestrial environments with potential implications on the sequestration of C and release of nutrients and pollutants. Full article

(This article belongs to the Special Issue Wastewater Treatment and Reuse)

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3266 KiB

Open AccessArticle

Effects of Streambed Conductance on Stream Depletion

by Greg Lackey, Roseanna M. Neupauer and John Pitlick

Water 2015, 7(1), 271-287; https://doi.org/10.3390/w7010271 - 12 Jan 2015

Cited by 26 | Viewed by 7548

Abstract

Stream depletion, which is the reduction in flow rate of a stream or river due to the extraction of groundwater in a hydraulically connected stream-aquifer system, is often estimated using numerical models. The accuracy of these models depends on the appropriate parameterization of [...] Read more.

Stream depletion, which is the reduction in flow rate of a stream or river due to the extraction of groundwater in a hydraulically connected stream-aquifer system, is often estimated using numerical models. The accuracy of these models depends on the appropriate parameterization of aquifer and streambed hydraulic properties. Streambed conductance is a parameter that relates the head difference between the stream and aquifer to flow across the stream channel. It is a function of streambed hydraulic conductivity and streambed geometry. In natural systems, streambed conductance varies spatially throughout the streambed; however, stream depletion modeling studies often ignore this variability. In this work, we use numerical simulations to demonstrate that stream depletion estimates are sensitive to a range of streambed conductance values depending on aquifer properties. We compare the stream depletion estimates from various spatial patterns of streambed conductance to show that modeling streambed conductance as a homogeneous property can lead to errors in stream depletion estimates. We use the results to identify feasible locations for proposed pumping wells such that the stream depletion due to pumping from a well within this feasible region would not exceed a prescribed threshold value, and we show that incorrect assumptions of the magnitude and spatial variability of streambed conductance can affect the size and shape of the feasible region. Full article

(This article belongs to the Special Issue Surface Water Groundwater Interactions: From Theory to Practice)

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Open AccessArticle

Comparing Methods of Calculating Expected Annual Damage in Urban Pluvial Flood Risk Assessments

by Anders Skovgård Olsen, Qianqian Zhou, Jens Jørgen Linde and Karsten Arnbjerg-Nielsen

Water 2015, 7(1), 255-270; https://doi.org/10.3390/w7010255 - 12 Jan 2015

Cited by 96 | Viewed by 12316

Abstract

Estimating the expected annual damage (EAD) due to flooding in an urban area is of great interest for urban water managers and other stakeholders. It is a strong indicator for a given area showing how vulnerable it is to flood risk and how [...] Read more.

Estimating the expected annual damage (EAD) due to flooding in an urban area is of great interest for urban water managers and other stakeholders. It is a strong indicator for a given area showing how vulnerable it is to flood risk and how much can be gained by implementing e.g., climate change adaptation measures. This study identifies and compares three different methods for estimating the EAD based on unit costs of flooding of urban assets. One of these methods was used in previous studies and calculates the EAD based on a few extreme events by assuming a log-linear relationship between cost of an event and the corresponding return period. This method is compared to methods that are either more complicated or require more calculations. The choice of method by which the EAD is calculated appears to be of minor importance. At all three case study areas it seems more important that there is a shift in the damage costs as a function of the return period. The shift occurs approximately at the 10 year return period and can perhaps be related to the design criteria for sewer systems. Further, it was tested if the EAD estimation could be simplified by assuming a single unit cost per flooded area. The results indicate that within each catchment this may be a feasible approach. However the unit costs varies substantially between different case study areas. Hence it is not feasible to develop unit costs that can be used to calculate EAD, most likely because the urban landscape is too heterogeneous. Full article

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Graphical abstract

157 KiB

Open AccessEditorial

Acknowledgement to Reviewers of Water in 2014

by Water Editorial Office

Water 2015, 7(1), 248-254; https://doi.org/10.3390/w7010248 - 07 Jan 2015

Viewed by 4372

Abstract

The editors of Water would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2014:[...] Full article

14891 KiB

Open AccessArticle

Empirical Modeling of Spatial 3D Flow Characteristics Using a Remote-Controlled ADCP System: Monitoring a Spring Flood

by Claude Flener, Yunsheng Wang, Leena Laamanen, Elina Kasvi, Jenni-Mari Vesakoski and Petteri Alho

Water 2015, 7(1), 217-247; https://doi.org/10.3390/w7010217 - 07 Jan 2015

Cited by 29 | Viewed by 11720

Abstract

The use of acoustic Doppler current profilers (ADCP) for measuring streamflow and discharge is becoming increasingly widespread. The spatial distribution of flow patterns is useful data in studying riverine habitats and geomorphology. Until now, most flow mapping has focused on measurements along a [...] Read more.

The use of acoustic Doppler current profilers (ADCP) for measuring streamflow and discharge is becoming increasingly widespread. The spatial distribution of flow patterns is useful data in studying riverine habitats and geomorphology. Until now, most flow mapping has focused on measurements along a series of transects in a channel. Here, we set out to measure, model and analyze the 3D flow characteristics of a natural river over a continuous areal extent, quantifying flow velocity, 3D flow directions, volumes, water depth and their changes over time. We achieved multidimensional spatial flow measurements by deploying an ADCP on a remotely-controlled boat, combined with kinematic GNSS positioning and locally-monitored water level data. We processed this data into a 3D point cloud of accurately positioned individual 3D flow measurements that allows the visual analysis of flow velocities, directions and channel morphology in 3D space. We demonstrate how this allows monitoring changes of flow patterns with a time series of flow point clouds measured over the period of a spring flood in Finnish Lapland. Furthermore, interpolating the raw point cloud onto a 3D matrix allows us to quantify volumetric flow while reducing noise in the data. We can now quantify the volumes of water moving at certain velocities in a given reach and their location in 3D space, allowing, for instance, the monitoring of the high-velocity core and its changes over time. Full article

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238 KiB

Open AccessArticle

Seasonal Demand Dynamics of Residential Water End-Uses

by Kumudu Rathnayaka, Hector Malano, Shiroma Maheepala, Biju George, Bandara Nawarathna, Meenakshi Arora and Peter Roberts

Water 2015, 7(1), 202-216; https://doi.org/10.3390/w7010202 - 07 Jan 2015

Cited by 51 | Viewed by 8715

Abstract

Water demand prediction by end-use at an appropriate spatial and temporal resolution is essential for planning water supply systems that will supply water from a diversified set of sources on a fit-for-purpose basis. Understanding seasonal, daily and sub-daily water demand including peak demand [...] Read more.

Water demand prediction by end-use at an appropriate spatial and temporal resolution is essential for planning water supply systems that will supply water from a diversified set of sources on a fit-for-purpose basis. Understanding seasonal, daily and sub-daily water demand including peak demand by end-uses is an essential planning requirement to implement a fit-for-purpose water supply strategy. Studies in the literature assume that all indoor water uses except evaporative cooler water use are weather independent and do not exhibit seasonal variability. This paper presents an analysis undertaken to examine seasonal variability of residential water end-uses. The analysis was repeated using two sets of data to ensure the validity of findings. The study shows that shower water use is significantly different between winter and summer, in addition to irrigation, evaporative cooler and pool water end-uses, while other water end-uses are not. Weather is shown to be a significant determinant of shower water use; in particular it affects shower duration which increases with lower temperature. Further analysis on shower water use suggests that it is driven by behavioural factors in addition to weather, thus providing useful insights to improve detailed end-use water demand predictions. Full article

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3726 KiB

Open AccessArticle

Tracing the Nitrate Sources of the Yili River in the Taihu Lake Watershed: A Dual Isotope Approach

by Haiao Zeng and Jinglu Wu

Water 2015, 7(1), 188-201; https://doi.org/10.3390/w7010188 - 31 Dec 2014

Cited by 16 | Viewed by 7287

Abstract

As the third largest freshwater lake in China, Taihu Lake has experienced severe cyanobacterial blooms and associated water quality degradation in recent decades, threatening the human health and sustainable development of cities in the watershed. The Yili River is a main river of [...] Read more.

As the third largest freshwater lake in China, Taihu Lake has experienced severe cyanobacterial blooms and associated water quality degradation in recent decades, threatening the human health and sustainable development of cities in the watershed. The Yili River is a main river of Taihu Lake, contributing about 30% of the total nitrogen load entering the lake. Tracing the nitrate sources of Yili River can inform the origin of eutrophication in Taihu Lake and provide hints for effective control measures. This paper explored the nitrate sources and cycling of the Yili River based on dual nitrogen (δ¹⁵N) and oxygen (δ¹⁸O) isotopic compositions. Water samples collected during both the wet and dry seasons from different parts of the Yili River permitted the analysis of the seasonal and spatial variations of nitrate concentrations and sources. Results indicated that the wet season has higher nitrate concentrations than the dry season despite the stronger dilution effects, suggesting a greater potential of cyanobacterial blooms in summer. The δ¹⁵N-NO₃⁻ values were in the range of 4.0‰–14.0‰ in the wet season and 4.8‰–16.9‰ in dry, while the equivalent values of δ¹⁸O were 0.5‰–17.8‰ and 3.5‰–15.6‰, respectively. The distribution of δ¹⁵N-NO₃⁻ and δ¹⁸O-NO₃⁻ indicated that sewage and manure as well as fertilizer and soil organic matter were the major nitrate sources of the Yili River. Atmospheric deposition was an important nitrate source in the upper part of Yili River but less so in the middle and lower reaches due to increasing anthropogenic contamination. Moreover, there was a positive relationship between δ¹⁸O-NO₃⁻ and δ¹⁵N-NO₃⁻ in the wet season, indicating a certain extent of denitrification. In contrast, the δ¹⁸O-δ¹⁵N relationship in the dry season was significantly negative, suggesting that the δ¹⁵N and δ¹⁸O values were determined by a mixing of different nitrate sources. Full article

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Open AccessArticle

Genetic Basis for Geosmin Production by the Water Bloom-Forming Cyanobacterium, Anabaena ucrainica

by Zhongjie Wang, Jihai Shao, Yao Xu, Biao Yan and Renhui Li

Water 2015, 7(1), 175-187; https://doi.org/10.3390/w7010175 - 31 Dec 2014

Cited by 19 | Viewed by 8073

Abstract

Geosmin is a common, musty-smelling sesquiterpene, principally produced by cyanobacteria. Anabaena ucrainica (Schhorb.) Watanabe, a water bloom-forming cyanobacterium, is the geosmin producer responsible for odor problems in Dianchi and Erhai lakes in China. In this study, the geosmin synthase gene (geo [...] Read more.

Geosmin is a common, musty-smelling sesquiterpene, principally produced by cyanobacteria. Anabaena ucrainica (Schhorb.) Watanabe, a water bloom-forming cyanobacterium, is the geosmin producer responsible for odor problems in Dianchi and Erhai lakes in China. In this study, the geosmin synthase gene (geo) of A. ucrainica and its flanking regions were identified and cloned by polymerase chain reaction (PCR) and genome walking. The geo gene was found to be located in a transcription unit with two cyclic nucleotide-binding protein genes (cnb). The two cnb genes were highly similar and were predicted members of the cyclic adenosine monophosphate (cAMP) receptor protein/fumarate nitrate reductase regulator (Crp–Fnr) family. Phylogenetic and evolutionary analyses implied that the evolution of the geosmin genes involved a horizontal gene transfer process in cyanobacteria. These genes showed a close relationship to 2-methylisoborneol genes in origin and evolution. Full article

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Open AccessReview

An Overview of Hybrid Water Supply Systems in the Context of Urban Water Management: Challenges and Opportunities

by Mukta Sapkota, Meenakshi Arora, Hector Malano, Magnus Moglia, Ashok Sharma, Biju George and Francis Pamminger

Water 2015, 7(1), 153-174; https://doi.org/10.3390/w7010153 - 29 Dec 2014

Cited by 69 | Viewed by 19093

Abstract

This paper presents a critical review of the physical impacts of decentralized water supply systems on existing centralized water infrastructures. This paper highlights the combination of centralized and decentralized systems, which is referred to as hybrid water supply systems. The system is hypothesized [...] Read more.

This paper presents a critical review of the physical impacts of decentralized water supply systems on existing centralized water infrastructures. This paper highlights the combination of centralized and decentralized systems, which is referred to as hybrid water supply systems. The system is hypothesized to generate more sustainable and resilient urban water systems. The basic concept is to use decentralized water supply options such as rainwater tanks, storm water harvesting and localized wastewater treatment and reuse in combination with centralized systems. Currently the impact of hybrid water supply technologies on the operational performance of the downstream infrastructure and existing treatment processes is yet to be known. The paper identifies a number of significant research gaps related to interactions between centralized and decentralized urban water services. It indicates that an improved understanding of the interaction between these systems is expected to provide a better integration of hybrid systems by improved sewerage and drainage design, as well as facilitate operation and maintenance planning. The paper also highlights the need for a framework to better understand the interaction between different components of hybrid water supply systems. Full article

(This article belongs to the Special Issue Water Quality Control and Management)

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487 KiB

Open AccessArticle

The Spanish Food Industry on Global Supply Chains and Its Impact on Water Resources

by Rosa Duarte, Vicente Pinilla and Ana Serrano

Water 2015, 7(1), 132-152; https://doi.org/10.3390/w7010132 - 29 Dec 2014

Cited by 12 | Viewed by 7146

Abstract

The study of the impact of economic activities on natural resources through global supply chains is increasingly demanded in the context of the growing globalization of economies and product fragmentation. Taking Spain as a case study and a sector with significant economic and [...] Read more.

The study of the impact of economic activities on natural resources through global supply chains is increasingly demanded in the context of the growing globalization of economies and product fragmentation. Taking Spain as a case study and a sector with significant economic and environmental impacts, the agri-food industry, the objective of this work is two-fold. First, we estimate the associated water impact, both from the production and consumption perspectives, paying special attention to the water embodied in production exchanges among countries and sectors. To that aim, we use an environmentally-extended multiregional input-output model (MRIO). Second, we assess the main driving factors behind changes in direct and embodied water consumption between the years 1995 and 2009 by means of a structural decomposition analysis. The MRIO model provides a comprehensive estimate of the economic linkages among regions and economic sectors and, therefore, allows calculating the environmental impacts over international value chains. The results indicate that the food industry exerts large impacts on global water resources, particularly given the remarkable interactions with the domestic and foreign agricultural sectors, These growing linkages show how consumption patterns, and, therefore, lifestyles, involve large environmental impacts through the whole and global supply chains. Full article

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967 KiB

Open AccessArticle

Effect of Dust Deposition on Stomatal Conductance and Leaf Temperature of Cotton in Northwest China

by Shamaila Zia-Khan, Wolfram Spreer, Yang Pengnian, Xiaoning Zhao, Hussein Othmanli, Xiongkui He and Joachim Müller

Water 2015, 7(1), 116-131; https://doi.org/10.3390/w7010116 - 24 Dec 2014

Cited by 64 | Viewed by 11511

Abstract

The Xinjiang Region in Northwest China is known as the “dust center” of the Eurasian mainland. Dust on the leaf surface affects overall plant development. While emphasis was on studying the impacts of industrial dust particles on crop development, the effect of natural [...] Read more.

The Xinjiang Region in Northwest China is known as the “dust center” of the Eurasian mainland. Dust on the leaf surface affects overall plant development. While emphasis was on studying the impacts of industrial dust particles on crop development, the effect of natural dust deposition on the physiological parameters of cotton had not been studied before. The objective of this study was to examine the effects of dust deposits on cotton leaves and to estimate their impact on crop development and yield. For this purpose, an experiment was set up having two treatments and a control. In Treatment 1, cotton leaves were cleaned with water at three-day intervals or after a natural dust fall. In Treatment 2, 100 g·m⁻² of dust was applied at 10-day intervals. The control received neither additional dust nor cleaning. In all of the treatments, stomatal conductance, leaf temperature, biomass and yield were measured. The results show a 28% reduction in yield and 30% reduction in stomatal conductance of the dust treatment compared to the control treatment. This indicates blocking of the stomata on the top of the leaf surface. In addition, the canopy temperature of the dust-applied leaves was always higher than the control and treatment. Full article

(This article belongs to the Special Issue Sustainable Water Management and Decision Making under limited Data Availability)

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Open AccessArticle

Development of Flow Forecasting Models in the Bow River at Calgary, Alberta, Canada

by Victor B. Veiga, Quazi K. Hassan and Jianxun He

Water 2015, 7(1), 99-115; https://doi.org/10.3390/w7010099 - 24 Dec 2014

Cited by 19 | Viewed by 7744

Abstract

River flow forecasting is critical for flood forecasting, reservoir operations, and water resources management. However, flow forecasting can be difficult, challenging and time consuming due to the spatial and temporal variability of climatic conditions and watershed characteristics. From a practical point of view, [...] Read more.

River flow forecasting is critical for flood forecasting, reservoir operations, and water resources management. However, flow forecasting can be difficult, challenging and time consuming due to the spatial and temporal variability of climatic conditions and watershed characteristics. From a practical point of view, a simple and intuitive approach might be more preferable than a complex modeling approach. In this study, our objective was to develop short-term (i.e., daily) flow forecasting models in the Bow River at the city of Calgary, Alberta, Canada. Here, we evaluated the performance of several regression models, along with a newly proposed “base difference” model, by using antecedent daily river flow values from three gauge stations (i.e., Banff, Seebe, and Calgary). Our analyses revealed that using a multivariable linear regression formulated as a function of upstream gauge stations (i.e., Banff or Seebe) and the station of interest (i.e., Calgary) using antecedent flows demonstrated strong relationships (i.e., having r² (coefficient of determination) and RMSE (root-mean-square deviation) of approximately 0.93 and 14 m³/s, respectively). As such, we opted to suggest that the use of Banff and Calgary stations in forecasting the flows at Calgary could be considered as it would require a relatively lower number of gauge stations. Full article

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Open AccessArticle

Volumetric Concentration Maximum of Cohesive Sediment in Waters: A Numerical Study

by Jisun Byun, Minwoo Son, Jeong-Seok Yang and Tae-Hwa Jung

Water 2015, 7(1), 81-98; https://doi.org/10.3390/w7010081 - 24 Dec 2014

Cited by 4 | Viewed by 7469

Abstract

Cohesive sediment has different characteristics compared to non-cohesive sediment. The density and size of a cohesive sediment aggregate (a so-called, floc) continuously changes through the flocculation process. The variation of floc size and density can cause a change of volumetric concentration under the [...] Read more.

Cohesive sediment has different characteristics compared to non-cohesive sediment. The density and size of a cohesive sediment aggregate (a so-called, floc) continuously changes through the flocculation process. The variation of floc size and density can cause a change of volumetric concentration under the condition of constant mass concentration. This study investigates how the volumetric concentration is affected by different conditions such as flow velocity, water depth, and sediment suspension. A previously verified, one-dimensional vertical numerical model is utilized here. The flocculation process is also considered by floc in the growth type flocculation model. Idealized conditions are assumed in this study for the numerical experiments. The simulation results show that the volumetric concentration profile of cohesive sediment is different from the Rouse profile. The volumetric concentration decreases near the bed showing the elevated maximum in the cases of both current and oscillatory flow. The density and size of floc show the minimum and the maximum values near the elevation of volumetric concentration maximum, respectively. This study also shows that the flow velocity and the critical shear stress have significant effects on the elevated maximum of volumetric concentration. As mechanisms of the elevated maximum, the strong turbulence intensity and increased mass concentration are considered because they cause the enhanced flocculation process. This study uses numerical experiments. To the best of our knowledge, no laboratory or field experiments on the elevated maximum have been carried out until now. It is of great necessity to conduct well-controlled laboratory experiments in the near future. Full article

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Open AccessArticle

Long-Term Changes in the Water Quality and Macroinvertebrate Communities of a Subtropical River in South China

by Kun Li, Chunguang He, Jie Zhuang, Zhenxing Zhang, Hongyong Xiang, Zhongqiang Wang, Haijun Yang and Lianxi Sheng

Water 2015, 7(1), 63-80; https://doi.org/10.3390/w7010063 - 24 Dec 2014

Cited by 19 | Viewed by 6920

Abstract

Subtropical rivers support a highly diverse array of benthic macroinvertebrates. In this study, by combining historical data and new data, we identified specific changes in the Guanlan River, in South China, from 1981 to 2011, and evaluated the effectiveness of an ecological restoration [...] Read more.

Subtropical rivers support a highly diverse array of benthic macroinvertebrates. In this study, by combining historical data and new data, we identified specific changes in the Guanlan River, in South China, from 1981 to 2011, and evaluated the effectiveness of an ecological restoration project under highly polluted conditions. From 1981 to 2011, the water quality in the Guanlan River underwent three major stages. With the deterioration of water quality, there was an overall decrease in the species number of macroinvertebrates in the Guanlan River, an increase in macroinvertebrate density, and a reduction of the biodiversity, and a reduction of functional feeding groups. In 2011, after five years of comprehensive remediation, the Guanlan River was somewhat improved. Macroinvertebrate biodiversity in the middle reach of the Guanlan River, where a key ecological restoration engineering project was implemented, did not differ significantly from other sites. This finding indicates that the effectiveness of ecological restoration measures in highly polluted rivers, particularly at the reach-scale, is very limited and even ineffective. Full article

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Open AccessArticle

Nitrate Removal from Wastewater through Biological Denitrification with OGA 24 in a Batch Reactor

by Federico Rossi, Oriana Motta, Simona Matrella, Antonio Proto and Giovanni Vigliotta

Water 2015, 7(1), 51-62; https://doi.org/10.3390/w7010051 - 23 Dec 2014

Cited by 52 | Viewed by 13252

Abstract

Nitrates pollution of waters is a worldwide problem and its remediation is a big challenge from the technical and the scientific point of view. One of the most used and promising cleaning techniques is the biological treatment of wastewaters operated by denitrifying bacteria. [...] Read more.

Nitrates pollution of waters is a worldwide problem and its remediation is a big challenge from the technical and the scientific point of view. One of the most used and promising cleaning techniques is the biological treatment of wastewaters operated by denitrifying bacteria. In this paper we begin a thorough study of denitrifying performances of the bacterium Azospira sp. OGA 24, recently isolated from the highly polluted Sarno river in the south of Italy. Here, the kinetics of nitrates consumption operated by bacteria in a specifically devised batch bioreactor, in anoxic condition and with acetate as the organic substrate, has been characterized. Experimental data were then used in a simplified model of a real wastewater treatment plant to find that OGA 24 can clean water with efficiency up to 90%. The denitrifying performances of OGA 24 match the requirements of Italian laws and make the bacterium suitable for its employment in treatment plants. Full article

(This article belongs to the Special Issue Water Treatment and Human Health)

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291 KiB

Open AccessReview

When Bioelectrochemical Systems Meet Forward Osmosis: Accomplishing Wastewater Treatment and Reuse through Synergy

by Yaobin Lu, Mohan Qin, Heyang Yuan, Ibrahim M. Abu-Reesh and Zhen He

Water 2015, 7(1), 38-50; https://doi.org/10.3390/w7010038 - 23 Dec 2014

Cited by 47 | Viewed by 13529

Abstract

Bioelectrochemical systems (BES) and forward osmosis (FO) are two emerging technologies with great potential for energy-efficient water/wastewater treatment. BES takes advantage of microbial interaction with a solid electron acceptor/donor to accomplish bioenergy recovery from organic compounds, and FO can extract high-quality water driven [...] Read more.

Bioelectrochemical systems (BES) and forward osmosis (FO) are two emerging technologies with great potential for energy-efficient water/wastewater treatment. BES takes advantage of microbial interaction with a solid electron acceptor/donor to accomplish bioenergy recovery from organic compounds, and FO can extract high-quality water driven by an osmotic pressure. The strong synergy between those two technologies may complement each other and collaboratively address water-energy nexus. FO can assist BES with achieving water recovery (for future reuse), enhancing electricity generation, and supplying energy for accomplishing the cathode reactions; while BES may help FO with degrading organic contaminants, providing sustainable draw solute, and stabilizing water flux. This work has reviewed the recent development that focuses on the synergy between BES and FO, analyzed the advantages of each combination, and provided perspectives for future research. The findings encourage further investigation and development for efficient coordination between BES and FO towards an integrated system for wastewater treatment and reuse. Full article

(This article belongs to the Special Issue Wastewater Treatment and Reuse)

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Open AccessArticle

Economic Feasibility of Irrigated Agricultural Land Use Buffers to Reduce Groundwater Nitrate in Rural Drinking Water Sources

by Megan M. Mayzelle, Joshua H. Viers, Josué Medellín-Azuara and Thomas Harter

Water 2015, 7(1), 12-37; https://doi.org/10.3390/w7010012 - 23 Dec 2014

Cited by 17 | Viewed by 9520

Abstract

Agricultural irrigation leachate is often the largest source for aquifer recharge in semi-arid groundwater basins, but contamination from fertilizers and other agro-chemicals may degrade the quality of groundwater. Affected communities are frequently economically disadvantaged, and water supply alternatives may be too costly. This [...] Read more.

Agricultural irrigation leachate is often the largest source for aquifer recharge in semi-arid groundwater basins, but contamination from fertilizers and other agro-chemicals may degrade the quality of groundwater. Affected communities are frequently economically disadvantaged, and water supply alternatives may be too costly. This study aimed to demonstrate that, when addressing these issues, environmental sustainability and market profitability are not incompatible. We investigated the viability of two low impact crops, alfalfa and vineyards, and new recharge basins as an alternative land use in recharge buffer zones around affected communities using an integrated hydrologic, socio-geographic, and economic analysis. In the southern Central Valley, California, study area, alfalfa and vineyards currently constitute 30% of all buffer zone cropland. Economic analyses of alternative land use scenarios indicate a wide range of revenue outcomes. Sector output gains and potential cost saving through land use conversion and resulting flood control result in gains of at least $2.3 billion, as compared to costs of $0.3 to $0.7 billion for treatment options over a 20 year period. Buffer zones would maintain the economic integrity of the region and concur with prevailing policy options. Thus, managed agricultural recharge buffer zones are a potentially attractive option for communities facing financial constraint and needing to diversify their portfolio of policy and infrastructure approaches to meet drinking water quality objectives. Full article

(This article belongs to the Special Issue Surface Water Groundwater Interactions: From Theory to Practice)

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Open AccessArticle

Prediction of Biomass Production and Nutrient Uptake in Land Application Using Partial Least Squares Regression Analysis

by Vasileios A. Tzanakakis, Andy Mauromoustakos and Andreas N. Angelakis

Water 2015, 7(1), 1-11; https://doi.org/10.3390/w7010001 - 23 Dec 2014

Cited by 10 | Viewed by 7082

Abstract

Partial Least Squares Regression (PLSR) can integrate a great number of variables and overcome collinearity problems, a fact that makes it suitable for intensive agronomical practices such as land application. In the present study a PLSR model was developed to predict important management [...] Read more.

Partial Least Squares Regression (PLSR) can integrate a great number of variables and overcome collinearity problems, a fact that makes it suitable for intensive agronomical practices such as land application. In the present study a PLSR model was developed to predict important management goals, including biomass production and nutrient recovery (i.e., nitrogen and phosphorus), associated with treatment potential, environmental impacts, and economic benefits. Effluent loading and a considerable number of soil parameters commonly monitored in effluent irrigated lands were considered as potential predictor variables during the model development. All data were derived from a three year field trial including plantations of four different plant species (Acacia cyanophylla, Eucalyptus camaldulensis, Populus nigra, and Arundo donax), irrigated with pre-treated domestic effluent. PLSR method was very effective despite the small sample size and the wide nature of data set (with many highly correlated inputs and several highly correlated responses). Through PLSR method the number of initial predictor variables was reduced and only several variables were remained and included in the final PLSR model. The important input variables maintained were: Effluent loading, electrical conductivity (EC), available phosphorus (Olsen-P), Na⁺, Ca²⁺, Mg²⁺, K²⁺, SAR, and NO₃⁻-N. Among these variables, effluent loading, EC, and nitrates had the greater contribution to the final PLSR model. PLSR is highly compatible with intensive agronomical practices such as land application, in which a large number of highly collinear and noisy input variables is monitored to assess plant species performance and to detect impacts on the environment. Full article

(This article belongs to the Special Issue Wastewater Treatment and Reuse)

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Water, Volume 7, Issue 1 (January 2015) – 21 articles , Pages 1-361

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