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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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21 pages, 557 KiB  
Article
Regarding Groundwater and Drinking Water Access through A Human Rights Lens: Self-Supply as A Norm
by Jenny Grönwall and Kerstin Danert
Water 2020, 12(2), 419; https://doi.org/10.3390/w12020419 - 5 Feb 2020
Cited by 106 | Viewed by 14249
Abstract
Globally, some 2.5 billion people depend solely on groundwater to satisfy their daily drinking water needs. The reliance on this resource and its centrality to realize the human right to ‘safe’ drinking water has increased manifold, but this is yet to be fully [...] Read more.
Globally, some 2.5 billion people depend solely on groundwater to satisfy their daily drinking water needs. The reliance on this resource and its centrality to realize the human right to ‘safe’ drinking water has increased manifold, but this is yet to be fully acknowledged globally or by governments and political leaders at the national level. This paper analyses the interface of international human rights law, as corresponding to the obligations and responsibilities of different actors, regarding groundwater resources planning, management and protection. Drawing on the literature, we discuss the State’s duties to respect, protect and fulfil this right especially in relation to the freedom of end-users to self-supply from groundwater sources; the training and regulation of non-State service providers including drillers and private vendors; and health and safety concerns. Interpreting the State’s duty to ‘fulfil’ through direct water service provision ‘as a last resort’, this paper suggests that self-provision is the original norm for enjoying the right to water. This has significant implications for the State’s role in raising awareness concerning point source protection and aquifer recharge for water resources management and in decisions concerning water allocation. By ignoring self-provision, which is primarily from groundwater, the State is not only missing a tremendous opportunity but is jeopardizing the water security of future generations. Full article
(This article belongs to the Special Issue Human Rights to Water and Sanitation)
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25 pages, 2815 KiB  
Review
Rethinking the Framework of Smart Water System: A Review
by Jiada Li, Xiafei Yang and Robert Sitzenfrei
Water 2020, 12(2), 412; https://doi.org/10.3390/w12020412 - 4 Feb 2020
Cited by 78 | Viewed by 13518
Abstract
Throughout the past years, governments, industries, and researchers have shown increasing interest in incorporating smart techniques, including sensor monitoring, real-time data transmitting, and real-time controlling into water systems. However, the design and construction of such a smart water system are still not quite [...] Read more.
Throughout the past years, governments, industries, and researchers have shown increasing interest in incorporating smart techniques, including sensor monitoring, real-time data transmitting, and real-time controlling into water systems. However, the design and construction of such a smart water system are still not quite standardized for massive applications due to the lack of consensus on the framework. The major challenge impeding wide application of the smart water network is the unavailability of a systematic framework to guide real-world design and deployment. To address this challenge, this review study aims to facilitate more extensive adoption of the smart water system, to increase effectiveness and efficiency in real-world water system contexts. A total of 32 literature pieces including 1 international forum, 17 peer-reviewed papers, 10 reports, and 4 presentations that are directly related to frameworks of smart water system have been reviewed. A new and comprehensive smart water framework, including definition and architecture, was proposed in this review paper. Two conceptual metrics (smartness and cyber wellness) were defined to evaluate the performance of smart water systems. Additionally, three pieces of future research suggestions were discussed, calling for broader collaboration in the community of researchers, engineers, and industrial and governmental sectors to promote smart water system applications. Full article
(This article belongs to the Special Issue Smart Urban Water Networks)
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26 pages, 2401 KiB  
Review
The Science behind Scour at Bridge Foundations: A Review
by Alonso Pizarro, Salvatore Manfreda and Enrico Tubaldi
Water 2020, 12(2), 374; https://doi.org/10.3390/w12020374 - 30 Jan 2020
Cited by 107 | Viewed by 11272
Abstract
Foundation scour is among the main causes of bridge collapse worldwide, resulting in significant direct and indirect losses. A vast amount of research has been carried out during the last decades on the physics and modelling of this phenomenon. The purpose of this [...] Read more.
Foundation scour is among the main causes of bridge collapse worldwide, resulting in significant direct and indirect losses. A vast amount of research has been carried out during the last decades on the physics and modelling of this phenomenon. The purpose of this paper is, therefore, to provide an up-to-date, comprehensive, and holistic literature review of the problem of scour at bridge foundations, with a focus on the following topics: (i) sediment particle motion; (ii) physical modelling and controlling dimensionless scour parameters; (iii) scour estimates encompassing empirical models, numerical frameworks, data-driven methods, and non-deterministic approaches; (iv) bridge scour monitoring including successful examples of case studies; (v) current approach for assessment and design of bridges against scour; and, (vi) research needs and future avenues. Full article
(This article belongs to the Special Issue Bridge Hydraulics: Current State of the Knowledge and Perspectives)
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23 pages, 902 KiB  
Article
An Innovative Tool for the Management of the Surface Drinking Water Resources at European Level: GOWARE—Transnational Guide Towards an Optimal WAter REgime
by Angela Rizzo, Primoz Banovec, Ajda Cilenšek, Guido Rianna and Monia Santini
Water 2020, 12(2), 370; https://doi.org/10.3390/w12020370 - 29 Jan 2020
Cited by 5 | Viewed by 4166
Abstract
GOWARE (transnational Guide toward an Optimal WAter REgime) represents a Decision Support Tool (DST) developed to support the implementation of innovative Best Management Practices (BMPs) for drinking water protection and flood/drought risk mitigation. The tool is one of the main outputs of the [...] Read more.
GOWARE (transnational Guide toward an Optimal WAter REgime) represents a Decision Support Tool (DST) developed to support the implementation of innovative Best Management Practices (BMPs) for drinking water protection and flood/drought risk mitigation. The tool is one of the main outputs of the PROLINE-CE Project, an EU project funded within the Interreg Central Europe (CE) Programme (2014–2020). The aim of this paper is illustrating the design and the methodological approaches proposed for the operative development of the tool. Furthermore, the paper provides the results of a number of tests carried out to evaluate the understandability of the analysis’s processes and assessing the stakeholders’ acceptance. Specifically, GOWARE-DST has been developed for supporting single users or groups of users in the decision-making process. The tool has been provided with a catalogue of 92 BMPs to handle water issues in different land use contexts. The selection of practices suitable for addressing the specific user’s requirements is supported by the Analytic Hierarchy Process, a method that allows filtering a subset of BMPs by accounting for the relative importance that the user assigns to each characterizing criterion. GOWARE-DST represents an innovative tool for supporting users at different levels of planning (operational and strategic) by promoting sustainable land and water management and defining long-term governance activities. Full article
(This article belongs to the Special Issue Efficient Practices of Land Use Management for Water Resources Protection)
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26 pages, 5893 KiB  
Article
Coastal Flooding and Erosion under a Changing Climate: Implications at a Low-Lying Coast (Ebro Delta)
by Albert Grases, Vicente Gracia, Manuel García-León, Jue Lin-Ye and Joan Pau Sierra
Water 2020, 12(2), 346; https://doi.org/10.3390/w12020346 - 25 Jan 2020
Cited by 54 | Viewed by 6345
Abstract
Episodic coastal hazards associated to sea storms are responsible for sudden and intense changes in coastal morphology. Climate change and local anthropogenic activities such as river regulation and urban growth are raising risk levels in coastal hotspots, like low-lying areas of river deltas. [...] Read more.
Episodic coastal hazards associated to sea storms are responsible for sudden and intense changes in coastal morphology. Climate change and local anthropogenic activities such as river regulation and urban growth are raising risk levels in coastal hotspots, like low-lying areas of river deltas. This urges to revise present management strategies to guarantee their future sustainability, demanding a detailed diagnostic of the hazard evolution. In this paper, flooding and erosion under current and future conditions have been assessed at local scale at the urban area of Riumar, a touristic enclave placed at the Ebro Delta (Spain). Process-based models have been used to address the interaction between beach morphology and storm waves, as well as the influence of coastal environment complexity. Storm waves have been propagated with SWAN wave model and have provided the forcings for XBeach, a 2DH hydro-morphodynamic model. Results show that future trends in sea level rise and wave forcing produce non-linear variations of the flooded area and the volume of mobilized sediment resulting from marine storms. In particular, the balance between flooding and sediment transport will shift depending on the relative sea level. Wave induced flooding and long-shore sand transport seem to be diminished in the future, whereas static sea level flooding and cross-shore sediment transport are exacerbated. Therefore, the characterization of tipping points in the coastal response can help to develop robust and adaptive plans to manage climate change impact in sandy wave dominated coasts with a low-lying hinterland and a complex shoreline morphology. Full article
(This article belongs to the Special Issue Effect of Climate Change on Coastal Hydrodynamics)
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11 pages, 3306 KiB  
Article
Assessing Aquifer Water Level and Salinity for a Managed Artificial Recharge Site Using Reclaimed Water
by Faten Jarraya Horriche and Sihem Benabdallah
Water 2020, 12(2), 341; https://doi.org/10.3390/w12020341 - 25 Jan 2020
Cited by 29 | Viewed by 4710
Abstract
This study was carried out to examine the impact of an artificial recharge site on groundwater level and salinity using treated domestic wastewater for the Korba aquifer (north eastern Tunisia). The site is located in a semi-arid region affected by seawater intrusion, inducing [...] Read more.
This study was carried out to examine the impact of an artificial recharge site on groundwater level and salinity using treated domestic wastewater for the Korba aquifer (north eastern Tunisia). The site is located in a semi-arid region affected by seawater intrusion, inducing an increase in groundwater salinity. Investigation of the subsurface enabled the identification of suitable areas for aquifer recharge mainly composed of sand formations. Groundwater flow and solute transport models (MODFLOW and MT3DMS) were then setup and calibrated for steady and transient states from 1971 to 2005 and used to assess the impact of the artificial recharge site. Results showed that artificial recharge, with a rate of 1500 m3/day and a salinity of 3.3 g/L, could produce a recovery in groundwater level by up to 2.7 m and a reduction in groundwater salinity by as much as 5.7 g/L over an extended simulation period. Groundwater monitoring for 2007–2014, used for model validation, allowed one to confirm that the effective recharge, reaching the water table, is less than the planned values. Full article
(This article belongs to the Special Issue Application of the Systems Approach to the Management of Complex Water Systems)
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21 pages, 2610 KiB  
Article
Roof-Harvested Rainwater Use in Household Agriculture: Contributions to the Sustainable Development Goals
by Caleb Christian Amos, Ataur Rahman, John Mwangi Gathenya, Eran Friedler, Fazlul Karim and Andre Renzaho
Water 2020, 12(2), 332; https://doi.org/10.3390/w12020332 - 23 Jan 2020
Cited by 16 | Viewed by 5608
Abstract
Food and water are at the heart of sustainable development. Roof-harvested rainwater kept in rainwater storage systems (RSS) and used in household agriculture (HA) has the potential to increase yields and supplement household nutrition. Combined systems may contribute to at least eight of [...] Read more.
Food and water are at the heart of sustainable development. Roof-harvested rainwater kept in rainwater storage systems (RSS) and used in household agriculture (HA) has the potential to increase yields and supplement household nutrition. Combined systems may contribute to at least eight of the United Nations’ 17 Sustainable Development Goals (SDGs). In this paper, a daily analysis tool, ERain, is used to assess what area of vegetables can be reliably irrigated by roof-harvested rainwater. A socio-economic context is built around an orphanage in the semi-humid region of Nakuru, Kenya. Comparisons are made with the semi-arid region of East Pokot. A 225 kL closed masonry tank and a 1 ML open reservoir with an additional 8 kL/day of recycled water entering are analyzed for various roof sizes. The 225 kL RSS connected to 1000 m2 of roof and irrigating 1000 m2 could increase yields from 1850 to 4200 kg/year in Nakuru. If evaporation was controlled, the 1 mL RSS and recycled water system could support 4000 m2 of land, yielding nearly 20,000 kg/year, which is enough to meet the WHO recommended vegetable dietary requirements of the orphanage. A combination of crops, some for consumption and some for sale, could be grown. Full article
(This article belongs to the Special Issue Rainwater and Stormwater Harvesting for Sustainable Water Cycle Management)
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16 pages, 1043 KiB  
Article
Human Health Risks Associated with Recreational Waters: Preliminary Approach of Integrating Quantitative Microbial Risk Assessment with Microbial Source Tracking
by Anna Gitter, Kristina D. Mena, Kevin L. Wagner, Diane E. Boellstorff, Kyna E. Borel, Lucas F. Gregory, Terry J. Gentry and Raghupathy Karthikeyan
Water 2020, 12(2), 327; https://doi.org/10.3390/w12020327 - 23 Jan 2020
Cited by 16 | Viewed by 4414
Abstract
Gastrointestinal (GI) illness risks associated with exposure to waters impacted by human and nonhuman fecal sources were estimated using quantitative microbial risk assessment (QMRA). Microbial source tracking (MST) results had identified Escherichia coli (E. coli) contributors to the waterbody as human [...] Read more.
Gastrointestinal (GI) illness risks associated with exposure to waters impacted by human and nonhuman fecal sources were estimated using quantitative microbial risk assessment (QMRA). Microbial source tracking (MST) results had identified Escherichia coli (E. coli) contributors to the waterbody as human and unidentified (10%), cattle and domestic animals (25%), and wildlife (65%) in a rural watershed. The illness risks associated with ingestion during recreation were calculated by assigning reference pathogens for each contributing source and using pathogen dose–response relationships. The risk of GI illness was calculated for a specific sampling site with a geometric mean of E. coli of 163 colony forming units (cfu) 100 mL−1, and the recreational standard of E. coli, 126 cfu 100 mL−1. While the most frequent sources of fecal indicator bacteria at the sampling site were nonhuman, the risk of illness from norovirus, the reference pathogen representing human waste, contributed the greatest risk to human health. This study serves as a preliminary review regarding the potential for incorporating results from library-dependent MST to inform a QMRA for recreational waters. The simulations indicated that identifying the sources contributing to the bacterial impairment is critical to estimate the human health risk associated with recreation in a waterbody. Full article
(This article belongs to the Section Water Quality and Contamination)
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20 pages, 2007 KiB  
Article
Impact of Sequential Treatments with Natural and Na-Exchanged Chabazite Zeolite-Rich Tuff on Pig-Slurry Chemical Composition
by Giacomo Ferretti, Giulio Galamini, Valeria Medoro, Massimo Coltorti, Dario Di Giuseppe and Barbara Faccini
Water 2020, 12(2), 310; https://doi.org/10.3390/w12020310 - 21 Jan 2020
Cited by 12 | Viewed by 2822
Abstract
Notwithstanding the widespread use of natural and pre-exchanged zeolites for zootechnical effluent treatment, little attention has been dedicated to the variation in the chemical composition of the treated slurries, besides the effects on their NH4+ content. This paper aimed at elucidating [...] Read more.
Notwithstanding the widespread use of natural and pre-exchanged zeolites for zootechnical effluent treatment, little attention has been dedicated to the variation in the chemical composition of the treated slurries, besides the effects on their NH4+ content. This paper aimed at elucidating the compositional variations in terms of major and trace elements of a raw pig-slurry (PS) after three sequential treatment cycles (TC) with three different grain sizes of natural and Na-exchanged zeolite-rich volcanic tuffs (natural ZTs and NaZTs). A series of laboratory batch experiments revealed that all ZTs had profoundly influenced the final PS chemical composition. As expected, the NaZTs were more efficient in terms of NH4+ removal than the natural ZTs, reaching almost 60% reduction of the initial content after three TCs. A parallel effect of this efficient removal was the remarkable increase in Na+. The Na-forms of ZTs led also to stronger competition with K+ ions, resulting in adsorption of this macronutrient and hence in a reduction of the fertilization value of the PS. In terms of heavy metals and other trace elements, all the treatments with ZTs had significantly increased the Li, Ba, Rb, Sr, Ga, and U content in the PS. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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20 pages, 959 KiB  
Article
Comprehensive Assessment Methodology for Urban Residential Rainwater Tank Implementation
by Ashok K. Sharma and Ted Gardner
Water 2020, 12(2), 315; https://doi.org/10.3390/w12020315 - 21 Jan 2020
Cited by 12 | Viewed by 4080
Abstract
Rainwater tanks are increasingly being implemented as part of the integrated urban water management paradigm where all sources of water, including potable, stormwater and recycled, are considered eligible to contribute to the urban water supply. Over the last decade or so, there has [...] Read more.
Rainwater tanks are increasingly being implemented as part of the integrated urban water management paradigm where all sources of water, including potable, stormwater and recycled, are considered eligible to contribute to the urban water supply. Over the last decade or so, there has been a rapid uptake of rainwater tank systems in urban areas, especially in Australian cities, encouraged through financial incentives, but more importantly, from change in residential building codes effectively mandating the installation of rainwater tanks. Homes with rainwater tanks in Australian cities have increased from 15% to 28% over six years to 2013. These building codes specify certain rainwater tank specifications to achieve a stated rainwater use, and hence potable water savings. These specifications include minimum rainwater tank size, minimum connected roof area, plumbing for internal supply for toilets and washing machines, and external supply for garden watering. These expected potable water savings from households are often factored into regional strategic water planning objectives. Hence if rainwater tanks do not deliver the expected saving due to sub-standard installation and/or poor maintenance, it will have an adverse impact on the regional water plan in the longer term. In this paper, a methodology to assess the effectiveness of a government rainwater tank policy in achieving predicted potable water savings is described and illustrated with a case study from South East Queensland, Australia. It is anticipated that water professionals across the globe should be able to use the same methodology to assess the effectiveness of similar rainwater policies, or indeed any other distributed water saving policy, in their local planning communities. Full article
(This article belongs to the Special Issue Smart Technologies and Water Supply Planning)
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18 pages, 2803 KiB  
Article
Reuse of Waste Geothermal Brine: Process, Thermodynamic and Economic Analysis
by Mauro Capocelli, Eugenio Moliterni, Vincenzo Piemonte and Marcello De Falco
Water 2020, 12(2), 316; https://doi.org/10.3390/w12020316 - 21 Jan 2020
Cited by 14 | Viewed by 5456
Abstract
Geothermal brines can be a resource of energy, freshwater and minerals. Even when rejected after their exploitation to produce energy in a power plant, the brines can be a source of freshwater and minerals, and can have a residual enthalpy that can be [...] Read more.
Geothermal brines can be a resource of energy, freshwater and minerals. Even when rejected after their exploitation to produce energy in a power plant, the brines can be a source of freshwater and minerals, and can have a residual enthalpy that can be recovered to produce additional power. The different reuse scenarios of these wasted brines depend on the composition and temperature at which they must be reinjected into the wells. On this basis, geothermal energy production is a perfect case study to investigate the water–energy nexus and to optimize the integrated energy- and water-production processes. In this paper, two case studies of brine reuse for both energy and water production are presented with the related process analysis, basic design and technical–economic analysis. A methodology to evaluate the exergy efficiency of the processes is presented by analyzing minimum work of separation, the maximum achievable work and the additional primary energy required for integrated production. The novel approach to estimate the process efficiency for integrated geothermal energy and desalination plants is applied to the case studies and discussed in light of literature results. Full article
(This article belongs to the Special Issue Technologies for Water Reuse: Current Status and Future Challenges)
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23 pages, 11215 KiB  
Article
Hydraulic Modeling of Beaver Dams and Evaluation of Their Impacts on Flood Events
by Michael Neumayer, Sonja Teschemacher, Sara Schloemer, Volker Zahner and Wolfgang Rieger
Water 2020, 12(1), 300; https://doi.org/10.3390/w12010300 - 19 Jan 2020
Cited by 21 | Viewed by 9660
Abstract
There is a general agreement on the impact of beaver dams regarding the increasing diversity of habitats and the improvement of the water quality, whereas the retention effect during flood events is still being discussed. In this study, we modeled 12 beaver dam [...] Read more.
There is a general agreement on the impact of beaver dams regarding the increasing diversity of habitats and the improvement of the water quality, whereas the retention effect during flood events is still being discussed. In this study, we modeled 12 beaver dam cascade scenarios in two catchments for eight flood events with a two-dimensional (2D) hydrodynamic model. The implementation of the potential cascades in the model is based on the developed three-stage model for predicting location-dependent dam cascades in Bavaria. A Bavaria-wide questionnaire regarding dam occurrences and characteristics in combination with a detailed survey of 51 dams was used to set up a prediction scheme. It was observed that beaver dams are most likely built in rivers with riparian forest, with widths from 2 to 11 m and depths smaller than 1 m. The hydraulic model results showed larger inundation areas (>+300%) for the beaver dam scenarios. There is a noticeable peak attenuation and translation for elevated peak discharges (five times the annual mean discharge: up to ≤13.1% and 2.75 h), but no remarkable effect could be observed for flood events with return periods of more than 2 years. We conclude from the results that beaver dam cascades can have an impact on runoff characteristics, but do not lead to relevant peak reductions during flood events and therefore cannot be counted as flood mitigation measure. Full article
(This article belongs to the Special Issue Process Based Modelling of Natural and Distributed Flood Control Measures)
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26 pages, 2419 KiB  
Review
Machine Learning and Data Analytic Techniques in Digital Water Metering: A Review
by Md Shamsur Rahim, Khoi Anh Nguyen, Rodney Anthony Stewart, Damien Giurco and Michael Blumenstein
Water 2020, 12(1), 294; https://doi.org/10.3390/w12010294 - 19 Jan 2020
Cited by 54 | Viewed by 10781
Abstract
Digital or intelligent water meters are being rolled out globally as a crucial component in improving urban water management. This is because of their ability to frequently send water consumption information electronically and later utilise the information to generate insights or provide feedback [...] Read more.
Digital or intelligent water meters are being rolled out globally as a crucial component in improving urban water management. This is because of their ability to frequently send water consumption information electronically and later utilise the information to generate insights or provide feedback to consumers. Recent advances in machine learning (ML) and data analytic (DA) technologies have provided the opportunity to more effectively utilise the vast amount of data generated by these meters. Several studies have been conducted to promote water conservation by analysing the data generated by digital meters and providing feedback to consumers and water utilities. The purpose of this review was to inform scholars and practitioners about the contributions and limitations of ML and DA techniques by critically analysing the relevant literature. We categorised studies into five main themes: (1) water demand forecasting; (2) socioeconomic analysis; (3) behaviour analysis; (4) water event categorisation; and (5) water-use feedback. The review identified significant research gaps in terms of the adoption of advanced ML and DA techniques, which could potentially lead to water savings and more efficient demand management. We concluded that further investigations are required into highly personalised feedback systems, such as recommender systems, to promote water-conscious behaviour. In addition, advanced data management solutions, effective user profiles, and the clustering of consumers based on their profiles require more attention to promote water-conscious behaviours. Full article
(This article belongs to the Special Issue Role of Intelligent Sensor Networks and Big Data Informatics for Enhanced Management of Urban Water and Energy Resources)
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13 pages, 3155 KiB  
Article
Interactions between Microalgae and Bacteria in the Treatment of Wastewater from Milk Whey Processing
by Francesca Marazzi, Micol Bellucci, Tania Fantasia, Elena Ficara and Valeria Mezzanotte
Water 2020, 12(1), 297; https://doi.org/10.3390/w12010297 - 19 Jan 2020
Cited by 44 | Viewed by 6124
Abstract
Milk whey processing wastewaters (MWPWs) are characterized by high COD and organic nitrogen content; the concentrations of phosphorus are also relevant. A microalgal-based process was tested at lab scale in order to assess the feasibility of treating MWPW without any dilution or pre-treatment. [...] Read more.
Milk whey processing wastewaters (MWPWs) are characterized by high COD and organic nitrogen content; the concentrations of phosphorus are also relevant. A microalgal-based process was tested at lab scale in order to assess the feasibility of treating MWPW without any dilution or pre-treatment. Different microalgal strains and populations were tested. Based on the obtained results, Scenedesmus acuminatus (SA) and a mixed population (PM) chiefly made of Chlorella, Scenedesmus, and Chlamydomonas spp. were grown in duplicate for 70 days in Plexiglas column photobioreactors (PBRs), fed continuously (2.5 L culture volume, 7 days hydraulic retention time). Nutrient removal, microalgae growth, photosynthetic efficiency, and the composition of microalgal populations in the columns were monitored. At steady state, the microalgal growth was similar for SA and PM. The average removal efficiencies for the main pollutants were: 93% (SA), 94% (PM) for COD; 88% (SA) and 90% (PM) for total N; and 69% (SA) and 73% (PM) for total P. The residual pollution levels in the effluent from the PBRs were low enough to allow their discharge into surface waters; such good results were achieved thanks to the synergy between the microalgae and bacteria in the CO2 and oxygen production/consumption and in the nitrogen mineralization. Full article
(This article belongs to the Special Issue Integration of Microalgal Based Processes in Wastewater Treatment)
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14 pages, 1012 KiB  
Communication
Algal Bloom Occurrence and Effects in Russia
by Zorigto Namsaraev, Anna Melnikova, Anastasia Komova, Vasily Ivanov, Anastasia Rudenko and Evgenii Ivanov
Water 2020, 12(1), 285; https://doi.org/10.3390/w12010285 - 18 Jan 2020
Cited by 34 | Viewed by 7696
Abstract
Eutrophication caused by the entry of nutrients into a water body may lead to algal bloom. Russia possesses the world’s second highest supply of renewable freshwater resources and has faced the problem of eutrophication for many years. Nevertheless, as far as we know, [...] Read more.
Eutrophication caused by the entry of nutrients into a water body may lead to algal bloom. Russia possesses the world’s second highest supply of renewable freshwater resources and has faced the problem of eutrophication for many years. Nevertheless, as far as we know, no general analysis of Russia’s algal bloom situation has been before carried out. We have analyzed mass media and scientific reports about algal outbreaks from 2016 to 2018, which allowed us to determine the geographical distribution of algal blooms in Russia, as well as the major effects of eutrophication. As a result, we showed that algal blooms happened in all major climate zones and all federal districts. Cyanobacteria are the most frequently reported photosynthetic organisms comprising algal blooms in freshwater reservoirs located in the continental part of Russia and in the Baltic Sea. Dinoflagellate dominated blooms are more characteristic for the coastal parts of the northeastern Pacific Ocean. The largest number of reports comes from the south of the European part of Russia. However, we did not find significant correlations between state statistics data on factors possibly affecting eutrophication (e.g., population, arable land area, fertilizers, livestock, air temperature, etc.) and the number of algal outbreaks in the regions. Mass media analysis showed that algal blooms attract considerable public attention in Russia, which requires the scientific community to actively participate in solving the problem. Full article
(This article belongs to the Special Issue Pollutant/Nutrient Transport and Fate under Changing Hydroclimatic Conditions)
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24 pages, 4679 KiB  
Article
Temporal Probability Assessment and Its Use in Landslide Susceptibility Mapping for Eastern Bhutan
by Abhirup Dikshit, Raju Sarkar, Biswajeet Pradhan, Ratiranjan Jena, Dowchu Drukpa and Abdullah M. Alamri
Water 2020, 12(1), 267; https://doi.org/10.3390/w12010267 - 17 Jan 2020
Cited by 36 | Viewed by 6229
Abstract
Landslides are one of the major natural disasters that Bhutan faces every year. The monsoon season in Bhutan is usually marked by heavy rainfall, which leads to multiple landslides, especially across the highways, and affects the entire transportation network of the nation. The [...] Read more.
Landslides are one of the major natural disasters that Bhutan faces every year. The monsoon season in Bhutan is usually marked by heavy rainfall, which leads to multiple landslides, especially across the highways, and affects the entire transportation network of the nation. The determinations of rainfall thresholds are often used to predict the possible occurrence of landslides. A rainfall threshold was defined along Samdrup Jongkhar–Trashigang highway in eastern Bhutan using cumulated event rainfall and antecedent rainfall conditions. Threshold values were determined using the available daily rainfall and landslide data from 2014 to 2017, and validated using the 2018 dataset. The threshold determined was used to estimate temporal probability using a Poisson probability model. Finally, a landslide susceptibility map using the analytic hierarchy process was developed for the highway to identify the sections of the highway that are more susceptible to landslides. The accuracy of the model was validated using the area under the receiver operating characteristic curves. The results presented here may be regarded as a first step towards understanding of landslide hazards and development of an early warning system for a region where such studies have not previously been conducted. Full article
(This article belongs to the Special Issue Rainfall Thresholds and Other Approaches for Landslide Prediction and Early Warning)
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85 pages, 16959 KiB  
Review
Characteristics, Main Impacts, and Stewardship of Natural and Artificial Freshwater Environments: Consequences for Biodiversity Conservation
by Marco Cantonati, Sandra Poikane, Catherine M. Pringle, Lawrence E. Stevens, Eren Turak, Jani Heino, John S. Richardson, Rossano Bolpagni, Alex Borrini, Núria Cid, Martina Čtvrtlíková, Diana M. P. Galassi, Michal Hájek, Ian Hawes, Zlatko Levkov, Luigi Naselli-Flores, Abdullah A. Saber, Mattia Di Cicco, Barbara Fiasca, Paul B. Hamilton, Jan Kubečka, Stefano Segadelli and Petr Znachoradd Show full author list remove Hide full author list
Water 2020, 12(1), 260; https://doi.org/10.3390/w12010260 - 16 Jan 2020
Cited by 148 | Viewed by 44809
Abstract
In this overview (introductory article to a special issue including 14 papers), we consider all main types of natural and artificial inland freshwater habitas (fwh). For each type, we identify the main biodiversity patterns and ecological features, human impacts on the system and [...] Read more.
In this overview (introductory article to a special issue including 14 papers), we consider all main types of natural and artificial inland freshwater habitas (fwh). For each type, we identify the main biodiversity patterns and ecological features, human impacts on the system and environmental issues, and discuss ways to use this information to improve stewardship. Examples of selected key biodiversity/ecological features (habitat type): narrow endemics, sensitive (groundwater and GDEs); crenobionts, LIHRes (springs); unidirectional flow, nutrient spiraling (streams); naturally turbid, floodplains, large-bodied species (large rivers); depth-variation in benthic communities (lakes); endemism and diversity (ancient lakes); threatened, sensitive species (oxbow lakes, SWE); diverse, reduced littoral (reservoirs); cold-adapted species (Boreal and Arctic fwh); endemism, depauperate (Antarctic fwh); flood pulse, intermittent wetlands, biggest river basins (tropical fwh); variable hydrologic regime—periods of drying, flash floods (arid-climate fwh). Selected impacts: eutrophication and other pollution, hydrologic modifications, overexploitation, habitat destruction, invasive species, salinization. Climate change is a threat multiplier, and it is important to quantify resistance, resilience, and recovery to assess the strategic role of the different types of freshwater ecosystems and their value for biodiversity conservation. Effective conservation solutions are dependent on an understanding of connectivity between different freshwater ecosystems (including related terrestrial, coastal and marine systems). Full article
(This article belongs to the Special Issue Multiplicity, Characteristics, Main Impacts, and Stewardship of Natural and Artificial Freshwater Environments: Consequences for Biodiversity Conservation)
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17 pages, 16221 KiB  
Article
Estimating Soil Organic Carbon in Agricultural Gypsiferous Soils by Diffuse Reflectance Spectroscopy
by Maria Jose Marques, Ana María Álvarez, Pilar Carral, Iris Esparza, Blanca Sastre and Ramón Bienes
Water 2020, 12(1), 261; https://doi.org/10.3390/w12010261 - 16 Jan 2020
Cited by 2 | Viewed by 3539
Abstract
Contents of soil organic carbon (SOC), gypsum, CaCO3, and quartz, among others, were analyzed and related to reflectance features in visible and near-infrared (VIS/NIR) range, using partial least square regression (PLSR) in ParLes software. Soil samples come from a sloping olive [...] Read more.
Contents of soil organic carbon (SOC), gypsum, CaCO3, and quartz, among others, were analyzed and related to reflectance features in visible and near-infrared (VIS/NIR) range, using partial least square regression (PLSR) in ParLes software. Soil samples come from a sloping olive grove managed by frequent tillage in a gypsiferous area of Central Spain. Samples were collected in three different layers, at 0–10, 10–20 and 20–30 cm depth (IPCC guidelines for Greenhouse Gas Inventories Programme in 2006). Analyses were performed by C Loss-On-Ignition, X-ray diffraction and water content by the Richards plates method. Significant differences for SOC, gypsum, and CaCO3 were found between layers; similarly, soil reflectance for 30 cm depth layers was higher. The resulting PLSR models (60 samples for calibration and 30 independent samples for validation) yielded good predictions for SOC (R2 = 0.74), moderate prediction ability for gypsum and were not accurate for the rest of rest of soil components. Importantly, SOC content was related to water available capacity. Soils with high reflectance features held c.a. 40% less water than soils with less reflectance. Therefore, higher reflectance can be related to degradation in gypsiferous soil. The starting point of soil degradation and further evolution could be established and mapped through remote sensing techniques for policy decision making. Full article
(This article belongs to the Special Issue Soil Erosion, Soil Desertification and Soil Conservation in Agri-Environment Systems)
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20 pages, 5590 KiB  
Article
Hydrological Modeling to Assess the Efficiency of Groundwater Replenishment through Natural Reservoirs in the Hungarian Drava River Floodplain
by Ali Salem, József Dezső, Mustafa El-Rawy and Dénes Lóczy
Water 2020, 12(1), 250; https://doi.org/10.3390/w12010250 - 16 Jan 2020
Cited by 28 | Viewed by 4616
Abstract
Growing drought hazard and water demand for agriculture, ecosystem conservation, and tourism in the Hungarian Drava river floodplain call for novel approaches to maintain wetland habitats and enhance agricultural productivity. Floodplain rehabilitation should be viewed as a complex landscape ecological issue which, beyond [...] Read more.
Growing drought hazard and water demand for agriculture, ecosystem conservation, and tourism in the Hungarian Drava river floodplain call for novel approaches to maintain wetland habitats and enhance agricultural productivity. Floodplain rehabilitation should be viewed as a complex landscape ecological issue which, beyond water management goals to relieve water deficit, ensures a high level of provision for a broad range of ecosystem services. This paper explores the hydrological feasibility of alternative water management, i.e., the restoration of natural reservoirs (abandoned paleochannels) to mitigate water shortage problems. To predict the efficiency of the project, an integrated surface water (Wetspass-M) and groundwater model (MODFLOW-NWT) was developed and calibrated with an eight-year data series. Different management scenarios for two natural reservoirs were simulated with filling rates ranging from 0.5 m3 s−1 to 1.5 m3 s−1. In both instances, a natural reservoir with a feeding rate of 1 m3 s−1 was found to be the best scenario. In this case 14 days of filling are required to reach the possible maximum reservoir stage of +2 m. The first meter rise increases the saturation of soil pores and the second creates an open surface water body. Two filling periods per year, each lasting for around 180 days, are required. The simulated water balance shows that reservoir–groundwater interactions are mainly governed by the inflow into and outflow from the reservoir. Such an integrated management scheme is applicable for floodplain rehabilitation in other regions with similar hydromorphological conditions and hazards, too. Full article
(This article belongs to the Special Issue Spatial Modelling in Water Resources Management)
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14 pages, 2585 KiB  
Article
Evaluation of the Groundwater Quality Using the Water Quality Index and Geostatistical Analysis in the Dier al-Balah Governorate, Gaza Strip, Palestine
by Moustafa El Baba, Prabin Kayastha, Marijke Huysmans and Florimond De Smedt
Water 2020, 12(1), 262; https://doi.org/10.3390/w12010262 - 16 Jan 2020
Cited by 79 | Viewed by 8587
Abstract
Groundwater contamination is a major problem in the Gaza Strip. In this study we investigate the groundwater quality in the Dier al-Balah Governorate. Water samples were collected from 19 municipal wells in April 2009 and April 2014 and analyzed for physio-chemical parameters (pH, [...] Read more.
Groundwater contamination is a major problem in the Gaza Strip. In this study we investigate the groundwater quality in the Dier al-Balah Governorate. Water samples were collected from 19 municipal wells in April 2009 and April 2014 and analyzed for physio-chemical parameters (pH, TDS, Ca2+, Mg2+, Na+, K+, Cl−, SO42–, HCO3− and NO3−). The aim of the research is to determine the groundwater quality and to produce groundwater quality maps using the water quality index (WQI) method and geostatistical analysis. The results show that all water samples are very saline due to the intrusion of Mediterranean seawater in the coastal aquifer. Differences in chemical composition between 2009 and 2014 indicate that about 1% more seawater was mixed with the groundwater in this period. The majority of the observed chemical parameters of all wells are well above the WHO water quality standards and all WQI values indicate that the water quality is problematic. The spatial variation of the WQI scores is modelled by a deterministic component expressing a linear dependence on the distance to the coastline and a stochastic residual described by an exponential variogram with a practical range of 3000 m. The mapping of the WQI scores and derived water quality classes is achieved through regression-kriging. The results indicate that the groundwater in a large area along the coastline is unsuitable for human consumption and comparison of the maps of 2009 and 2014 shows that this region further expanded by about 700 m inland in a period of 5 years. The results of this study are worrying, but they also contribute to a better understanding of the factors that determine the groundwater quality and can help authorities and stakeholders with sustainable development. Full article
(This article belongs to the Special Issue Seawater Intrusion into Coastal Aquifers)
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19 pages, 4469 KiB  
Article
Physical Model Study on Discharge over a Dam Due to Landslide Generated Waves
by Netsanet Nigatu Tessema, Fjóla G. Sigtryggsdóttir, Leif Lia and Asie Kemal Jabir
Water 2020, 12(1), 234; https://doi.org/10.3390/w12010234 - 15 Jan 2020
Cited by 1 | Viewed by 4348
Abstract
Impulse waves generated by landslides falling into reservoirs may lead to overtopping of a dam and, in turn, to flooding of the downstream area. In the case of an embankment dam, the overtopping may lead to erosion of the downstream slope, ultimately resulting [...] Read more.
Impulse waves generated by landslides falling into reservoirs may lead to overtopping of a dam and, in turn, to flooding of the downstream area. In the case of an embankment dam, the overtopping may lead to erosion of the downstream slope, ultimately resulting in breaching and complete failure with consequent further hazardous release of water to the downstream area. This research deals with the overtopping process of a dam due to landslide generated waves in a three-dimensional (3D) physical scale model setup. Experiments have been conducted with varying the slide, reservoir, and dam parameters. The primary focus is on investigating the feasibility of employing the steady state weir equation in order to predict the overtopping discharge over a dam crest due to landslide generated waves. Calibration and validation of the coefficient of discharge values for the different dam section are conducted for the specified model setup. Accordingly, a two-step calculation procedure is presented for predicting the overtopping discharge based on the maximum overtopping depth values. Hence, for the fixed setup, which includes a constant slope angle of the landslide surface, a predictive equation for maximum overtopping depth is proposed, based on slide volume, slide release height, still water depth, upstream dam slope angle, and dam height. The relative slide volume and relative still water depth both seem to have a significant effect on the relative overtopping depth. Full article
(This article belongs to the Section Hydraulics and Hydrodynamics)
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12 pages, 3464 KiB  
Article
Multi-Objective Optimization for Selecting and Siting the Cost-Effective BMPs by Coupling Revised GWLF Model and NSGAII Algorithm
by Zuoda Qi, Gelin Kang, Xiaojin Wu, Yuting Sun and Yuqiu Wang
Water 2020, 12(1), 235; https://doi.org/10.3390/w12010235 - 15 Jan 2020
Cited by 12 | Viewed by 3065
Abstract
Best management practices (BMPs) are an effective way to control water pollution. However, identification of the optimal distribution and cost-effect of BMPs provides a great challenge for watershed policy makers. In this paper, a semi-distributed, low-data, and robust watershed model, the Revised Generalized [...] Read more.
Best management practices (BMPs) are an effective way to control water pollution. However, identification of the optimal distribution and cost-effect of BMPs provides a great challenge for watershed policy makers. In this paper, a semi-distributed, low-data, and robust watershed model, the Revised Generalized Watershed Loading Function (RGWLF), is improved by adding the pollutant attenuation process in the river channel and a bank filter strips reduction function. Three types of pollution control measures—point source wastewater treatment, bank filter strips, and converting farmland to forest—are considered, and the cost of each measure is determined. Furthermore, the RGWLF watershed model is coupled with a widely recognized multi-objective optimization algorithm, the non-dominated sorting genetic algorithm II (NSGAII), the combination of which is applied in the Luanhe watershed to search for spatial BMPs for dissolved nitrogen (DisN). Fifty scenarios were finally selected from numerous possibilities and the results indicate that, at a minimum cost of 9.09 × 107 yuan, the DisN load is 3.1 × 107 kg and, at a maximum cost of 1.77 × 108 yuan, the total dissolved nitrogen load is 1.31 × 107 kg; with the no-measures scenario, the DisN load is 4.05 × 107 kg. This BMP optimization model system could assist decision-makers in determining a scientifically comprehensive plan to realize cost-effective goals for the watershed. Full article
(This article belongs to the Special Issue Water Resources Management Models for Policy Assessment)
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21 pages, 10958 KiB  
Article
A Comparative Study of Kernel Logistic Regression, Radial Basis Function Classifier, Multinomial Naïve Bayes, and Logistic Model Tree for Flash Flood Susceptibility Mapping
by Binh Thai Pham, Tran Van Phong, Huu Duy Nguyen, Chongchong Qi, Nadhir Al-Ansari, Ata Amini, Lanh Si Ho, Tran Thi Tuyen, Hoang Phan Hai Yen, Hai-Bang Ly, Indra Prakash and Dieu Tien Bui
Water 2020, 12(1), 239; https://doi.org/10.3390/w12010239 - 15 Jan 2020
Cited by 103 | Viewed by 7674
Abstract
Risk of flash floods is currently an important problem in many parts of Vietnam. In this study, we used four machine-learning methods, namely Kernel Logistic Regression (KLR), Radial Basis Function Classifier (RBFC), Multinomial Naïve Bayes (NBM), and Logistic Model Tree (LMT) to generate [...] Read more.
Risk of flash floods is currently an important problem in many parts of Vietnam. In this study, we used four machine-learning methods, namely Kernel Logistic Regression (KLR), Radial Basis Function Classifier (RBFC), Multinomial Naïve Bayes (NBM), and Logistic Model Tree (LMT) to generate flash flood susceptibility maps at the minor part of Nghe An province of the Center region (Vietnam) where recurrent flood problems are being experienced. Performance of these four methods was evaluated to select the best method for flash flood susceptibility mapping. In the model studies, ten flash flood conditioning factors, namely soil, slope, curvature, river density, flow direction, distance from rivers, elevation, aspect, land use, and geology, were chosen based on topography and geo-environmental conditions of the site. For the validation of models, the area under Receiver Operating Characteristic (ROC), Area Under Curve (AUC), and various statistical indices were used. The results indicated that performance of all the models is good for generating flash flood susceptibility maps (AUC = 0.983–0.988). However, performance of LMT model is the best among the four methods (LMT: AUC = 0.988; KLR: AUC = 0.985; RBFC: AUC = 0.984; and NBM: AUC = 0.983). The present study would be useful for the construction of accurate flash flood susceptibility maps with the objectives of identifying flood-susceptible areas/zones for proper flash flood risk management. Full article
(This article belongs to the Special Issue Advances in Flash Flood Forecasting)
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28 pages, 5057 KiB  
Article
Long-Term Isotope Records of Precipitation in Zagreb, Croatia
by Ines Krajcar Bronić, Jadranka Barešić, Damir Borković, Andreja Sironić, Ivanka Lovrenčić Mikelić and Polona Vreča
Water 2020, 12(1), 226; https://doi.org/10.3390/w12010226 - 14 Jan 2020
Cited by 42 | Viewed by 5642
Abstract
The isotope composition of precipitation has been monitored in monthly precipitation at Zagreb, Croatia, since 1976. Here, we present a statistical analysis of available long-term isotope data (3H activity concentration, δ2H, δ18O, and deuterium excess) and compare [...] Read more.
The isotope composition of precipitation has been monitored in monthly precipitation at Zagreb, Croatia, since 1976. Here, we present a statistical analysis of available long-term isotope data (3H activity concentration, δ2H, δ18O, and deuterium excess) and compare them to basic meteorological data. The aim was to see whether isotope composition reflected observed climate changes in Zagreb: a significant increase in the annual air temperature and larger variations in the precipitation amount. Annual mean δ18O and δ2H values showed an increase of 0.017‰ and 0.14‰ per year, respectively, with larger differences in monthly mean values in the first half of the year than in the second half. Mean annual d-excess remained constant over the whole long-term period, with a tendency for monthly mean d-excess values to decrease in the first half of the year and increase in the second half due to the influence of air masses originating from the eastern Mediterranean. Changes in the stable isotope composition of precipitation thus resembled changes in the temperature, the circulation pattern of air masses, and the precipitation regime. A local meteoric water line was obtained using different regression methods, which did not result in significant differences between nonweighted and precipitation-weighted slope and intercept values. Deviations from the Global Meteoric Water Line GMWL (lower slopes and intercepts) were observed in two recent periods and could be explained by changes in climate parameters. The temperature gradient of δ18O was 0.33‰/°C. The tritium activity concentrations in precipitation showed slight decreases during the last two decades, and the mean A in the most recent period, 2012–2018, was 7.6 ± 0.8 Tritium Units (TU). Full article
(This article belongs to the Special Issue Use of Water Stable Isotopes in Hydrological Process)
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21 pages, 9815 KiB  
Article
3D Numerical Investigation of Forces and Flow Field around the Semi-Submersible Platform in An Internal Solitary Wave
by Weiye Ding, Congfang Ai, Sheng Jin and Jinbo Lin
Water 2020, 12(1), 208; https://doi.org/10.3390/w12010208 - 11 Jan 2020
Cited by 22 | Viewed by 3368
Abstract
Characteristics of hydrodynamic forces and flow fields around the semi-submersible platform induced by the internal solitary wave (ISW) propagation were investigated in a 3D numerical wave tank. Good agreements between numerical results and experimental data of forces and torque on the platform were [...] Read more.
Characteristics of hydrodynamic forces and flow fields around the semi-submersible platform induced by the internal solitary wave (ISW) propagation were investigated in a 3D numerical wave tank. Good agreements between numerical results and experimental data of forces and torque on the platform were achieved. The hydrodynamic loads increased and decreased with the increases in the ISW amplitude and fluid depth ratio, respectively. The pressure mainly contributed to the force on the platform. The horizontal forces on bracings were negligible. Almost all the vertical forces on the platform were derived from those on pontoons. The horizontal force and torque on the platform increased with the increases in the angle between the platform symmetrical axis and the ISW propagation direction. The platform subjected the maximum vertical force when the angle was 0°. There were obvious velocity reductions around the platform during the ISW propagation, as visible vortexes shedding around the platform could be observed. Complexities of the distributions of flow fields around the platforms located at the 30°- and 60°-direction were greater than those around the platforms located at the 0°- and 90°-direction. Flow fields around the same kind components of each platform located at different angles were similar. Full article
(This article belongs to the Section Hydraulics and Hydrodynamics)
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20 pages, 1225 KiB  
Article
Gender Perspective in Water Management: The Involvement of Women in Participatory Water Institutions of Eastern India
by Varsha Khandker, Vasant P. Gandhi and Nicky Johnson
Water 2020, 12(1), 196; https://doi.org/10.3390/w12010196 - 10 Jan 2020
Cited by 27 | Viewed by 9442
Abstract
The paper examines the extent, nature, and factors affecting women’s involvement in participatory irrigation institutions of eastern India. Effective participatory water institutions are urgently needed to improve water management in eastern India, and a significant aspect of this is the involvement of women. [...] Read more.
The paper examines the extent, nature, and factors affecting women’s involvement in participatory irrigation institutions of eastern India. Effective participatory water institutions are urgently needed to improve water management in eastern India, and a significant aspect of this is the involvement of women. There is inadequate representation, participation, and involvement of women in most water institutions. From the participatory and social point of view, this is a significant concern. The relevant data are obtained from the states of Assam and Bihar through a focused survey administered to 109 women in 30 water institutions, and a larger farmer-institutional survey covering 510 households and 51 water institutions. The research examines the extent and nature of the involvement of women in these institutions, as well as in farm decision-making, and the factors that prevent or foster their participation. Additionally, it examines the gender congruence in views regarding water institution activities and their performance, and the perceived benefits of formal involvement of women. The results show that their inclusion is very low (except required inclusion in Bihar), and the concerns of women are usually not being taken into account. Women are involved in farming and water management decisions jointly with men but not independently. Findings indicate that the views of women and men differ on many aspects, and so their inclusion is important. Responses indicate that if women participate formally in water user associations, it would enhance their social and economic standing, achieve greater gender balance, expand their awareness of water management, and contribute to better decision-making in the water institutions. Full article
(This article belongs to the Special Issue Using Applied Economics to Study Participatory Irrigation Institutions and their Impact in South Asia)
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20 pages, 17388 KiB  
Article
Climate Change Impacts on Hydropower in Yunnan, China
by Benxi Liu, Jay R. Lund, Lingjun Liu, Shengli Liao, Gang Li and Chuntian Cheng
Water 2020, 12(1), 197; https://doi.org/10.3390/w12010197 - 10 Jan 2020
Cited by 15 | Viewed by 6842
Abstract
Climate change could have dire effects on hydropower systems, especially in southwest China, where hydropower dominates the regional power system. This study examines two large cascade hydropower systems in Yunnan province in southwest China for 10 climate change projections made with 5 global [...] Read more.
Climate change could have dire effects on hydropower systems, especially in southwest China, where hydropower dominates the regional power system. This study examines two large cascade hydropower systems in Yunnan province in southwest China for 10 climate change projections made with 5 global climate models (GCMs) and 2 representative concentration pathways (RCPs) under Coupled Model Intercomparison Project Phase 5 (CMIP5). First, a back propagation neural network rain-runoff model is built for each hydropower station to estimate inflows with climate change. Then, a progressive optimality algorithm maximizes hydropower generation for each projection. The results show generation increasing in each GCM projection, but increasing more in GCMs under scenario RCP8.5. However, yearly generation fluctuates more: generation decreases dramatically with potential for electricity shortages in dry years and more electricity as well as spill during wet years. Average annual spill, average annual inflow and average storage have similar trends. The analysis indicates that a planned large dam on the upper Jinsha River would increase seasonal regulation ability, increase hydropower generation, and decrease spill. Increased turbine capacity increases generation slightly and decreases spill for the Lancang River. Results from this study demonstrate effects of climate change on hydropower systems and identify which watersheds might be more vulnerable, along with some actions that could help adapt to climate change. Full article
(This article belongs to the Special Issue System Dynamics Modelling for Water–Energy–Climate Nexus)
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15 pages, 3161 KiB  
Article
Comparison of Long Short Term Memory Networks and the Hydrological Model in Runoff Simulation
by Hongxiang Fan, Mingliang Jiang, Ligang Xu, Hua Zhu, Junxiang Cheng and Jiahu Jiang
Water 2020, 12(1), 175; https://doi.org/10.3390/w12010175 - 8 Jan 2020
Cited by 99 | Viewed by 11724
Abstract
Runoff modeling is one of the key challenges in the field of hydrology. Various approaches exist, ranging from physically based over conceptual to fully data driven models. In this paper, we propose a data driven approach using the state-of-the-art Long-Short-Term-Memory (LSTM) network. The [...] Read more.
Runoff modeling is one of the key challenges in the field of hydrology. Various approaches exist, ranging from physically based over conceptual to fully data driven models. In this paper, we propose a data driven approach using the state-of-the-art Long-Short-Term-Memory (LSTM) network. The proposed model was applied in the Poyang Lake Basin (PYLB) and its performance was compared with an Artificial Neural Network (ANN) and the Soil & Water Assessment Tool (SWAT). We first tested the impacts of the number of previous time step (window size) in simulation accuracy. Results showed that a window in improper large size will dramatically deteriorate the model performance. In terms of PYLB, a window size of 15 days might be appropriate for both accuracy and computational efficiency. We then trained the model with 2 different input datasets, namely, dataset with precipitation only and dataset with all available meteorological variables. Results demonstrate that although LSTM with precipitation data as the only input can achieve desirable results (where the NSE ranged from 0.60 to 0.92 for the test period), the performance can be improved simply by feeding the model with more meteorological variables (where NSE ranged from 0.74 to 0.94 for the test period). Moreover, the comparison results with the ANN and the SWAT showed that the ANN can get comparable performance with the SWAT in most cases whereas the performance of LSTM is much better. The results of this study underline the potential of the LSTM for runoff modeling especially for areas where detailed topographical data are not available. Full article
(This article belongs to the Special Issue Wetland Ecohydrology and Water Resource Management)
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34 pages, 2584 KiB  
Review
Research Trends in the Use of Remote Sensing for Inland Water Quality Science: Moving Towards Multidisciplinary Applications
by Simon N. Topp, Tamlin M. Pavelsky, Daniel Jensen, Marc Simard and Matthew R. V. Ross
Water 2020, 12(1), 169; https://doi.org/10.3390/w12010169 - 7 Jan 2020
Cited by 199 | Viewed by 17416
Abstract
Remote sensing approaches to measuring inland water quality date back nearly 50 years to the beginning of the satellite era. Over this time span, hundreds of peer-reviewed publications have demonstrated promising remote sensing models to estimate biological, chemical, and physical properties of inland [...] Read more.
Remote sensing approaches to measuring inland water quality date back nearly 50 years to the beginning of the satellite era. Over this time span, hundreds of peer-reviewed publications have demonstrated promising remote sensing models to estimate biological, chemical, and physical properties of inland waterbodies. Until recently, most of these publications focused largely on algorithm development as opposed to implementation of those algorithms to address specific science questions. This slow evolution contrasts with terrestrial and oceanic remote sensing, where methods development in the 1970s led to publications focused on understanding spatially expansive, complex processes as early as the mid-1980s. This review explores the progression of inland water quality remote sensing from methodological development to scientific applications. We use bibliometric analysis to assess overall patterns in the field and subsequently examine 236 key papers to identify trends in research focus and scale. The results highlight an initial 30 year period where the majority of publications focused on model development and validation followed by a spike in publications, beginning in the early-2000s, applying remote sensing models to analyze spatiotemporal trends, drivers, and impacts of changing water quality on ecosystems and human populations. Recent and emerging resources, including improved data availability and enhanced processing platforms, are enabling researchers to address challenging science questions and model spatiotemporally explicit patterns in water quality. Examination of the literature shows that the past 10–15 years has brought about a focal shift within the field, where researchers are using improved computing resources, datasets, and operational remote sensing algorithms to better understand complex inland water systems. Future satellite missions promise to continue these improvements by providing observational continuity with spatial/spectral resolutions ideal for inland waters. Full article
(This article belongs to the Section Water Quality and Contamination)
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30 pages, 8104 KiB  
Article
Determining the Impact of Riparian Wetlands on Nutrient Cycling, Storage and Export in Permeable Agricultural Catchments
by Penny J. Johnes, Daren C. Gooddy, Timothy H. E. Heaton, Andrew Binley, Michael P. Kennedy, Paul Shand and Hannah Prior
Water 2020, 12(1), 167; https://doi.org/10.3390/w12010167 - 6 Jan 2020
Cited by 16 | Viewed by 6178
Abstract
The impact of riparian wetlands on the cycling, retention and export of nutrients from land to water varies according to local environmental conditions and is poorly resolved in catchment management approaches. To determine the role a specific wetland might play in a catchment [...] Read more.
The impact of riparian wetlands on the cycling, retention and export of nutrients from land to water varies according to local environmental conditions and is poorly resolved in catchment management approaches. To determine the role a specific wetland might play in a catchment mitigation strategy, an alternative approach is needed to the high-frequency and spatially detailed monitoring programme that would otherwise be needed. Here, we present a new approach using a combination of novel and well-established geochemical, geophysical and isotope ratio methods. This combined approach was developed and tested against a 2-year high-resolution sampling programme in a lowland permeable wetland in the Lambourn catchment, UK. The monitoring programme identified multiple pathways and water sources feeding into the wetland, generating large spatial and temporal variations in nutrient cycling, retention and export behaviours within the wetland. This complexity of contributing source areas and biogeochemical functions within the wetland were effectively identified using the new toolkit approach. We propose that this technique could be used to determine the likely net source/sink function of riparian wetlands prior to their incorporation into any catchment management plan, with relatively low resource implications when compared to a full high-frequency nutrient speciation and isotope geochemistry-based monitoring approach. Full article
(This article belongs to the Special Issue Hydrological and Chemical Controls on Nutrient and Contaminant Loss to Water in Agricultural Landscapes)
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30 pages, 15040 KiB  
Article
A Three-Dimensional Numerical Model with an L-Type Wave-Maker System for Water Wave Simulations by the Moving Boundary Method
by Wei Jia, Shuxue Liu, Jinxuan Li and Yuping Fan
Water 2020, 12(1), 161; https://doi.org/10.3390/w12010161 - 5 Jan 2020
Cited by 5 | Viewed by 3676
Abstract
A three-dimensional numerical wave tank was developed based on Reynolds averaged Navier–Stokes equations and the volume of fluid method. The moving boundary method is adopted in this model to generate water waves. Piston-type wave-makers are mimicked for the total replication of the physical [...] Read more.
A three-dimensional numerical wave tank was developed based on Reynolds averaged Navier–Stokes equations and the volume of fluid method. The moving boundary method is adopted in this model to generate water waves. Piston-type wave-makers are mimicked for the total replication of the physical wave tank conditions. Two-dimensional regular and irregular waves are simulated, with the capability to trigger the active wave absorption algorithm. The two-sided wave-maker system with L-type arrangement is adopted in this model to expand the effective wave areas for three-dimensional waves. Oblique regular waves and multidirectional random waves are simulated, yielding a good agreement with theoretical solutions. The results indicate that this numerical model is an effective tool to provide finer details or complement data unavailable due to the physical setting of a tank experiment. Full article
(This article belongs to the Section Hydraulics and Hydrodynamics)
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18 pages, 6904 KiB  
Article
Turbulent Flow Field around Horizontal Cylinders with Scour Hole
by Nadia Penna, Francesco Coscarella and Roberto Gaudio
Water 2020, 12(1), 143; https://doi.org/10.3390/w12010143 - 2 Jan 2020
Cited by 14 | Viewed by 4046
Abstract
This study presents the results of an experimental investigation on the flow-structure interactions at scoured horizontal cylinders, varying the gap between the cylinder and the bed surface. A 2D Particle Image Velocimetry (PIV) system was used to measure the flow field in a [...] Read more.
This study presents the results of an experimental investigation on the flow-structure interactions at scoured horizontal cylinders, varying the gap between the cylinder and the bed surface. A 2D Particle Image Velocimetry (PIV) system was used to measure the flow field in a vertical plane at the end of the scouring process. Instantaneous and ensemble-averaged velocity and vorticity fields, viscous and Reynolds stresses, and ensemble-averaged turbulence indicators were calculated. Longitudinal bed profiles were measured at the equilibrium. The results revealed that suspended and laid on cylinders behave differently from half-buried cylinders if subjected to the same hydraulic conditions. In the latter case, vortex shedding downstream of the cylinder is suppressed by the presence of the bed surface that causes an asymmetry in the development of the vortices. This implies that strong turbulent mixing processes occur downstream of the uncovered cylinders, whereas in the case of half-buried cylinders they are confined within the scour hole. Full article
(This article belongs to the Special Issue Turbulence and Flow–Sediment Interactions in Open-Channel Flows)
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26 pages, 4482 KiB  
Article
Selecting Bacteria Candidates for the Bioaugmentation of Activated Sludge to Improve the Aerobic Treatment of Landfill Leachate
by Justyna Michalska, Artur Piński, Joanna Żur and Agnieszka Mrozik
Water 2020, 12(1), 140; https://doi.org/10.3390/w12010140 - 1 Jan 2020
Cited by 30 | Viewed by 5049
Abstract
In this study, a multifaceted approach for selecting the suitable candidates for bioaugmentation of activated sludge (AS) that supports leachate treatment was used. To determine the exploitation of 10 bacterial strains isolated from the various matrices for inoculating the AS contaminated with the [...] Read more.
In this study, a multifaceted approach for selecting the suitable candidates for bioaugmentation of activated sludge (AS) that supports leachate treatment was used. To determine the exploitation of 10 bacterial strains isolated from the various matrices for inoculating the AS contaminated with the Kalina pond leachate (KPL), their degradative potential was analyzed along with their aptitude to synthesize compounds improving remediation of pollutants in wastewater and ability to incorporate into the AS flocs. Based on their capability to degrade aromatic compounds (primarily catechol, phenol, and cresols) at a concentration of 1 mg/mL and survive in 12.5% of the KPL, Pseudomonas putida OR45a and P. putida KB3 can be considered to be the best candidates for bioaugmentation of the AS among all of the bacteria tested. Genomic analyses of these two strains revealed the presence of the genes encoding enzymes related to the metabolism of aromatic compounds. Additionally, both microorganisms exhibited a high hydrophobic propensity (above 50%) and an ability to produce biosurfactants as well as high resistance to ammonium (above 600 µg/mL) and heavy metals (especially chromium). These properties enable the exploitation of both bacterial strains in the bioremediation of the AS contaminated with the KPL. Full article
(This article belongs to the Special Issue Microbial Action in Wastewater and Sludge)
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19 pages, 1886 KiB  
Review
Stable Isotopes of Water and Nitrate for the Identification of Groundwater Flowpaths: A Review
by Hyejung Jung, Dong-Chan Koh, Yun S. Kim, Sung-Wook Jeen and Jeonghoon Lee
Water 2020, 12(1), 138; https://doi.org/10.3390/w12010138 - 1 Jan 2020
Cited by 41 | Viewed by 14810
Abstract
Nitrate contamination in stream water and groundwater is a serious environmental problem that arises in areas of high agricultural activities or high population density. It is therefore important to identify the source and flowpath of nitrate in water bodies. In recent decades, the [...] Read more.
Nitrate contamination in stream water and groundwater is a serious environmental problem that arises in areas of high agricultural activities or high population density. It is therefore important to identify the source and flowpath of nitrate in water bodies. In recent decades, the dual isotope analysis (δ15N and δ18O) of nitrate has been widely applied to track contamination sources by taking advantage of the difference in nitrogen and oxygen isotope ratios for different sources. However, transformation processes of nitrogen compounds can change the isotopic composition of nitrate due to the various redox processes in the environment, which often makes it difficult to identify contaminant sources. To compensate for this, the stable water isotope of the H2O itself can be used to interpret the complex hydrological and hydrochemical processes for the movement of nitrate contaminants. Therefore, the present study aims at understanding the fundamental background of stable water and nitrate isotope analysis, including isotope fractionation, analytical methods such as nitrate concentration from samples, instrumentation, and the typical ranges of δ15N and δ18O from various nitrate sources. In addition, we discuss hydrograph separation using the oxygen and hydrogen isotopes of water in combination with the nitrogen and oxygen isotopes of nitrate to understand the relative contributions of precipitation and groundwater to stream water. This study will assist in understanding the groundwater flowpaths as well as tracking the sources of nitrate contamination using the stable isotope analysis in combination with nitrate and water. Full article
(This article belongs to the Special Issue Use of Water Stable Isotopes in Hydrological Process)
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33 pages, 1899 KiB  
Article
Water and Climate Change, Two Key Objectives in the Agenda 2030: Assessment of Climate Literacy Levels and Social Representations in Academics from Three Climate Contexts
by Amor Escoz-Roldán, José Gutiérrez-Pérez and Pablo Ángel Meira-Cartea
Water 2020, 12(1), 92; https://doi.org/10.3390/w12010092 - 26 Dec 2019
Cited by 21 | Viewed by 5216
Abstract
The relationship between climate change and water is an obvious and key issue within the United Nations Sustainable Development Goals. This study aims to investigate the social representation created around this relationship in three different territorial contexts in order to evaluate the influence [...] Read more.
The relationship between climate change and water is an obvious and key issue within the United Nations Sustainable Development Goals. This study aims to investigate the social representation created around this relationship in three different territorial contexts in order to evaluate the influence of the territory on the perception of the risk of climate change and its relationship with water. By means of a questionnaire completed by 1709 university students, the climatic literacy of the individual was evaluated in order to relate it to other dimensions on the relationship between climate change and water (information, training previous on climate change and pro-environmental attitudes) in their different dimensions in three different territorial contexts. Three hypotheses have been tested: (1) The denial of the CC is significantly associated with a representation that belittles the consequences of global warming and other extreme phenomena. (2) Territorial contexts with high average rainfall levels and low average annual temperatures tend to minimize the social representation of water risks associated with the CC. (3) There is significant interaction between the socio-cultural context and social representations on the causes, consequences and solutions to the problems of CC and water. The first two hypotheses have been rejected, while the third has been accepted. The research results show high climate literacy in the samples of selected university students. It is noted that students recognize a close relationship between the problem of water and the climate crisis. Likewise, they identify different types of causes, consequences, physical processes and solutions. Different climatological contexts do not show significant differences in the social representations that students show about climate change, while socio-educational variables such as available scientific information, or ideology orientation do show significant differences. Full article
(This article belongs to the Special Issue Water Literacy and Education)
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13 pages, 1916 KiB  
Article
Smart Water Management towards Future Water Sustainable Networks
by Helena M. Ramos, Aonghus McNabola, P. Amparo López-Jiménez and Modesto Pérez-Sánchez
Water 2020, 12(1), 58; https://doi.org/10.3390/w12010058 - 21 Dec 2019
Cited by 76 | Viewed by 18361
Abstract
Water management towards smart cities is an issue increasingly appreciated under financial and environmental sustainability focus in any water sector. The main objective of this research is to disclose the technological breakthroughs associated with water and energy use. A methodology is proposed and [...] Read more.
Water management towards smart cities is an issue increasingly appreciated under financial and environmental sustainability focus in any water sector. The main objective of this research is to disclose the technological breakthroughs associated with water and energy use. A methodology is proposed and applied in a case study to analyze the benefits to develop smart water grids, showing the advantages offered by the development of control measures. The case study showed the positive results, particularly savings of 57 GWh and 100 Mm3 in a period of twelve years when different measures from the common ones were developed for the monitoring and control of water losses in smart water management. These savings contributed to reducing the CO2 emissions to 47,385 t CO2-eq. Finally, in order to evaluate the financial effort and savings obtained in this reference systems (RS) network, the investment required in the monitoring and water losses control in a correlation model case (CMC) was estimated, and, as a consequence, the losses level presented a significant reduction towards sustainable values in the next nine years. Since the pressure control is one of the main issues for the reduction of leakage, an estimation of energy production for Portugal is also presented. Full article
(This article belongs to the Special Issue New Challenges in Water Systems)
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31 pages, 10607 KiB  
Article
Spatial Data Management and Numerical Modelling: Demonstrating the Application of the QGIS-Integrated FREEWAT Platform at 13 Case Studies for Tackling Groundwater Resource Management
by Giovanna De Filippis, Christos Pouliaris, Daniel Kahuda, Teodora Alexandra Vasile, Valentina Adriana Manea, Florian Zaun, Björn Panteleit, Filiz Dadaser-Celik, Pio Positano, Marco Saulo Nannucci, Mykhailo Grodzynskyi, Andres Marandi, Manuel Sapiano, Irena Kopač, Andreas Kallioras, Massimiliano Cannata, Youssef Filiali-Meknassi, Laura Foglia, Iacopo Borsi and Rudy Rossetto
Water 2020, 12(1), 41; https://doi.org/10.3390/w12010041 - 20 Dec 2019
Cited by 19 | Viewed by 7771
Abstract
Because of the spatial nature of groundwater-related data and their time component, effective groundwater management requires the application of methods pertaining to the Information and Communication Technologies sector, such as spatial data management and distributed numerical modelling. The objective of this paper is [...] Read more.
Because of the spatial nature of groundwater-related data and their time component, effective groundwater management requires the application of methods pertaining to the Information and Communication Technologies sector, such as spatial data management and distributed numerical modelling. The objective of this paper is to demonstrate the effectiveness of the QGIS-integrated FREEWAT platform and an approach combining spatial data management and numerical models to target groundwater management issues. FREEWAT is a free and open source platform integrated in a Geographic Information System environment and embedding tools for pre- and post-processing of spatial data and integrating numerical codes for the simulation of the hydrological cycle, with a main focus on groundwater. To this aim, this paper briefly presents the FREEWAT platform, introduces the FREEWAT approach, and showcases 13 case studies in European and non-European countries where the FREEWAT platform was applied. Application of the FREEWAT platform to real-world case studies is presented for targeting management of coastal aquifers, ground- and surface-water interaction, climate change impacts, management of transboundary aquifers, rural water management and protection of groundwater-dependent ecosystems. In this sense, compared to other existing software suites, FREEWAT allows data analysis and visualization to accomplish each step of the modelling workflow, i.e., from data analytics, to conceptual model definition, to numerical modelling and reporting of results. The presented experiences demonstrate that improved access to data and the portability of models and models’ results can help to promote water sustainability from the local- to the basin-scale. Furthermore, FREEWAT may represent a valuable tool to target the objective of increasing the capabilities of public authorities and private companies to manage groundwater resources by means of up-to-date, robust, well-documented and reliable software, without entailing the need of costly licensing, nowadays seldom affordable by public water authorities. Based on the strengths highlighted, the FREEWAT platform is a powerful tool for groundwater resources management, and for data collection, sharing, implementation and comparison of scenarios, for supporting planning and decision-making. Full article
(This article belongs to the Section Water Resources Management, Policy and Governance)
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11 pages, 4286 KiB  
Communication
Design of a Smart System for Rapid Bacterial Test
by Rajshree Patil, Saurabh Levin, Samuel Rajkumar and Tahmina Ajmal
Water 2020, 12(1), 15; https://doi.org/10.3390/w12010015 - 19 Dec 2019
Cited by 2 | Viewed by 3903
Abstract
In this article, we present our initial findings to support the design of an advanced field test to detect bacterial contamination in water samples. The system combines the use of image processing and neural networks to detect an early presence of bacterial activity. [...] Read more.
In this article, we present our initial findings to support the design of an advanced field test to detect bacterial contamination in water samples. The system combines the use of image processing and neural networks to detect an early presence of bacterial activity. We present here a proof of concept with some tests results. Our initial findings are very promising and indicate detection of viable bacterial cells within a period of 2 h. To the authors’ knowledge this is the first attempt to quantify viable bacterial cells in a water sample using cell splitting. We also present a detailed design of the complete system that uses the time lapse images from a microscope to complete the design of a neural network based smart system. Full article
(This article belongs to the Special Issue Technological Eco-Innovations for the Quality Control and the Decontamination of Polluted Waters and Soils)
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30 pages, 466 KiB  
Review
Performance of Anammox Processes for Wastewater Treatment: A Critical Review on Effects of Operational Conditions and Environmental Stresses
by Sunja Cho, Cicilia Kambey and Van Khanh Nguyen
Water 2020, 12(1), 20; https://doi.org/10.3390/w12010020 - 19 Dec 2019
Cited by 126 | Viewed by 11822
Abstract
The anaerobic ammonium oxidation (anammox) process is well-known as a low-energy consuming and eco-friendly technology for treating nitrogen-rich wastewater. Although the anammox reaction was widely investigated in terms of its application in many wastewater treatment processes, practical anammox application at the pilot and [...] Read more.
The anaerobic ammonium oxidation (anammox) process is well-known as a low-energy consuming and eco-friendly technology for treating nitrogen-rich wastewater. Although the anammox reaction was widely investigated in terms of its application in many wastewater treatment processes, practical anammox application at the pilot and industrial scales is limited because nitrogen removal efficiency and anammox activity are dependent on many operational factors such as temperature, pH, dissolved oxygen concentration, nitrogen loading, and organic matter content. In practical application, anammox bacteria are possibly vulnerable to non-essential compounds such as sulfides, toxic metal elements, alcohols, phenols, and antibiotics that are potential inhibitors owing to the complexity of the wastewater stream. This review systematically summarizes up-to-date studies on the effect of various operational factors on nitrogen removal performance along with reactor type, mode of operation (batch or continuous), and cultured anammox bacterial species. The effect of potential anammox inhibition factors such as high nitrite concentration, high salinity, sulfides, toxic metal elements, and toxic organic compounds is listed with a thorough interpretation of the synergistic and antagonistic toxicity of these inhibitors. Finally, the strategy for optimization of anammox processes for wastewater treatment is suggested, and the importance of future studies on anammox applications is indicated. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
21 pages, 7962 KiB  
Article
Performance Evaluation of a Tidal Current Turbine with Bidirectional Symmetrical Foils
by Bin Guo, Dazheng Wang, Xu Zhou, Weichao Shi and Fengmei Jing
Water 2020, 12(1), 22; https://doi.org/10.3390/w12010022 - 19 Dec 2019
Cited by 15 | Viewed by 3272
Abstract
As one might expect, tidal currents in terms of ebb and flood tides are approximately bidirectional. A Horizontal Axial Tidal Turbine (HATT) with unidirectional foils has to be able to face the current directions in order to maximize current energy harvesting. There are [...] Read more.
As one might expect, tidal currents in terms of ebb and flood tides are approximately bidirectional. A Horizontal Axial Tidal Turbine (HATT) with unidirectional foils has to be able to face the current directions in order to maximize current energy harvesting. There are two regular solutions to keep a HATT always facing the direction of the flow, which are transferred from wind turbine applications. One is to yaw the turbine around the supporting structure with a yaw mechanism. The other is to reverse the blade pitch angle through 180° with a pitch-adjusting mechanism. The above solutions are not cost-effective in marine applications due to the harsh marine environment and high cost of installation and maintenance. In order to avoid the above disadvantages, a turbine with bidirectional foils is presented in this paper. A bare turbine with bidirectional foils is characterized in that it has nearly the same energy conversion capability in both tidal current directions without using the yaw or pitch mechanism. Considering the working conditions of the bidirectional turbine in which the turbine is installed on a mono-pile, the effect of the mono-pile on the turbine’s performance is evaluated in this paper, especially when the turbine is downstream of the mono-pile. The paper was focused on the evaluation of the hydrodynamic performance of the bidirectional turbine. The hydrodynamic performance of the bare bidirectional turbine without any supporting structure was evaluated based on a steady-state computational fluid dynamics (CFD) model and model tests. Performance comparison has been made between the turbine with bidirectional foils and the turbine with NACA foils. The effect of the mono-pile on the performance of the bidirectional turbine was studied by using the steady-state and the transient CFD model. The steady-state CFD model was used to evaluate the effect of the mono-pile clearance, which is the distance between the mono-pile and the turbine on the performance of the turbine. The transient CFD model was used to determine the time-dependent characteristics of the turbine, such as time-dependent power and drag coefficients. The results show that the bare bidirectional turbine has nearly the same energy conversion capability in both tidal current directions. The performance of the bidirectional turbine is inferior to the turbine with NACA foils. At the designed tip speed ratio, the power coefficient of the turbine with NACA foils is 0.4498, which increases by 1.6% compared to the 0.4338 of the bidirectional turbine. The turbine’s performance decreases due to the introduction of the mono-pile, and the closer the turbine is to the mono-pile, the greater effect on the turbine’s performance the mono-pile has. At the designed clearance of 1.5 DS, the presence of a mono-pile decreases the peak Cp value by 1.82% and 3.17% to a value of 0.4156 and 0.4004 for the turbine located in the mono-pile upstream and downstream, respectively. The mono-pile can result in the fluctuation of the turbine’s performance. This fluctuation will detrimentally harm the life of the turbine as it will lead to increased wear and fatigue issues. Full article
(This article belongs to the Section Hydraulics and Hydrodynamics)
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21 pages, 1521 KiB  
Article
An Analysis of Energy Consumption and the Use of Renewables for a Small Drinking Water Treatment Plant
by Saria Bukhary, Jacimaria Batista and Sajjad Ahmad
Water 2020, 12(1), 28; https://doi.org/10.3390/w12010028 - 19 Dec 2019
Cited by 35 | Viewed by 8204
Abstract
One of the pressing issues currently faced by the water industry is incorporating sustainability considerations into design practice and reducing the carbon emissions of energy-intensive processes. Water treatment, an indispensable step for safeguarding public health, is an energy-intensive process. The purpose of this [...] Read more.
One of the pressing issues currently faced by the water industry is incorporating sustainability considerations into design practice and reducing the carbon emissions of energy-intensive processes. Water treatment, an indispensable step for safeguarding public health, is an energy-intensive process. The purpose of this study was to analyze the energy consumption of an existing drinking water treatment plant (DWTP), then conduct a modeling study for using photovoltaics (PVs) to offset that energy consumption, and thus reduce emissions. The selected plant, located in southwestern United States, treats 0.425 m3 of groundwater per second by utilizing the processes of coagulation, filtration, and disinfection. Based on the energy consumption individually determined for each unit process (validated using the DWTP’s data), the DWTP was sized for PVs (as a modeling study). The results showed that the dependency of a DWTP on the traditional electric grid could be greatly reduced by the use of PVs. The largest consumption of energy was associated with the pumping operations, corresponding to 150.6 Wh m−3 for the booster pumps to covey water to the storage tanks, while the energy intensity of the water treatment units was found to be 3.1 Wh m−3. A PV system with a 1.5 MW capacity with battery storage (30 MWh) was found to have a positive net present value and a levelized cost of electricity of 3.1 cents kWh−1. A net reduction in the carbon emissions was found as 950 and 570 metric tons of CO2-eq year−1 due to the PV-based design, with and without battery storage, respectively. Full article
(This article belongs to the Special Issue Integrated Assessment of the Water–Energy–Land Nexus)
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14 pages, 4044 KiB  
Article
Removal of Microcystis aeruginosa through the Combined Effect of Plasma Discharge and Hydrodynamic Cavitation
by Blahoslav Maršálek, Eliška Maršálková, Klára Odehnalová, František Pochylý, Pavel Rudolf, Pavel Stahel, Jozef Rahel, Jan Čech, Simona Fialová and Štěpán Zezulka
Water 2020, 12(1), 8; https://doi.org/10.3390/w12010008 - 18 Dec 2019
Cited by 18 | Viewed by 4657
Abstract
Cyanobacterial water blooms represent toxicological, ecological and technological problems around the globe. When present in raw water used for drinking water production, one of the best strategies is to remove the cyanobacterial biomass gently before treatment, avoiding cell destruction and cyanotoxins release. This [...] Read more.
Cyanobacterial water blooms represent toxicological, ecological and technological problems around the globe. When present in raw water used for drinking water production, one of the best strategies is to remove the cyanobacterial biomass gently before treatment, avoiding cell destruction and cyanotoxins release. This paper presents a new method for the removal of cyanobacterial biomass during drinking water pre-treatment that combines hydrodynamic cavitation with cold plasma discharge. Cavitation produces press stress that causes Microcystis gas vesicles to collapse. The cyanobacteria then sink, allowing for removal by sedimentation. The cyanobacteria showed no signs of revitalisation, even after seven days under optimal conditions with nutrient enrichment, as photosynthetic activity is negatively affected by hydrogen peroxide produced by plasma burnt in the cavitation cloud. Using this method, cyanobacteria can be removed in a single treatment, with no increase in microcystin concentration. This novel technology appears to be highly promising for continual treatment of raw water inflow in drinking water treatment plants and will also be of interest to those wishing to treat surface waters without the use of algaecides. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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14 pages, 1871 KiB  
Article
Solar Septic Tank: Next Generation Sequencing Reveals Effluent Microbial Community Composition as a Useful Index of System Performance
by Stephanie Connelly, Tatchai Pussayanavin, Richard J. Randle-Boggis, Araya Wicheansan, Suparat Jampathong, Ciara Keating, Umer Z. Ijaz, Willian T. Sloan and Thammarat Koottatep
Water 2019, 11(12), 2660; https://doi.org/10.3390/w11122660 - 17 Dec 2019
Cited by 14 | Viewed by 10381
Abstract
Septic tanks are widely deployed for off-grid sewage management but are typified by poor treatment performance, discharge of polluting effluents and the requirement for frequent de-sludging. The Solar Septic Tank (SST) is a novel septic tank design that uses passive heat from the [...] Read more.
Septic tanks are widely deployed for off-grid sewage management but are typified by poor treatment performance, discharge of polluting effluents and the requirement for frequent de-sludging. The Solar Septic Tank (SST) is a novel septic tank design that uses passive heat from the sun to raise in-tank temperatures and improves solids degradation, resulting in a cleaner effluent. Treatment has been shown to exceed conventional systems, however, the underlying biology driving treatment in the system is poorly understood. We used next generation sequencing (Illumina Miseq (San Diego, CA, USA), V4 region 16S DNA) to monitor the microbiology in the sludge and effluent of two mature systems, a conventional septic tank and an SST, during four months of routine operation in Bangkok, Thailand, and evaluated the ecology against a suite of operating and performance data collected during the same time period. Significant differences were observed between the microbiome of the sludge and effluent in each system and the dominant taxa in each appeared persistent over time. Furthermore, variation in the microbial community composition in the system effluents correlated with effluent water quality and treatment performance parameters, including the removal of chemical and biochemical oxygen demand and the concentration of fecal and total coliforms in the effluent. Thus, we propose that a wide-scale survey of the biology underlying decentralised biotechnologies for sewage treatment such as the SST could be conducted by sampling system effluent rather than sampling sludge. This is advantageous as accessing sludge during sampling is both hazardous and potentially disruptive to the anaerobic methanogenic consortia underlying treatment in the systems. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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15 pages, 7911 KiB  
Article
Field Testing of Porous Pavement Performance on Runoff and Temperature Control in Taipei City
by Yung-Yun Cheng, Shang-Lien Lo, Chia-Chun Ho, Jen-Yang Lin and Shaw L. Yu
Water 2019, 11(12), 2635; https://doi.org/10.3390/w11122635 - 13 Dec 2019
Cited by 38 | Viewed by 5232
Abstract
The Taipei University of Technology, under contract from the Taipei City Government, completed a study on porous asphalt (PA) and permeable interlocking concrete brick (PICB) pavement performance with respect to stormwater runoff reduction and surface temperature mitigation. Additionally, the variation of infiltration rates [...] Read more.
The Taipei University of Technology, under contract from the Taipei City Government, completed a study on porous asphalt (PA) and permeable interlocking concrete brick (PICB) pavement performance with respect to stormwater runoff reduction and surface temperature mitigation. Additionally, the variation of infiltration rates against time of these pavements was monitored. The results show the following: (a) Runoff peak reduction ranged from 16% for large, intense storms to 55% for small, long-duration storms. Rainfall volume reduction ranged from 16% to 77% with an average of 37.6%; (b) Infiltration rate: for PICB, it decreased by 25% to 50% over a 15-month monitoring period, but the rate at one location increased significantly after cleaning; for PA, the rate remained high at one location, but decreased by 70%–80% after 10 months at two other locations, due mainly to clogging problems; (c) Surface temperature: during storm events, porous concrete bricks had on average lower temperatures compared to regular concrete with a maximum difference of 6.6 °C; for porous asphalt the maximum drop was 3.9 °C. During dry days, both PA and PICB showed a tendency of faster temperature increase as the air temperature rose, but also faster temperature decreases as the air cooled when compared to regular pavements. On very hot days, much lower surface temperatures were observed for porous pavements (for PA: 17.0 °C and for PICB: 14.3 °C) than those for regular pavements. The results suggest that large-scale applications of porous pavements could help mitigate urban heat island impacts. Full article
(This article belongs to the Section Urban Water Management)
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11 pages, 4232 KiB  
Article
Bridging the Data Gap in the Water Scarcity Footprint by Using Crop-Specific AWARE Factors
by Anne-Marie Boulay, Léo Lenoir and Alessandro Manzardo
Water 2019, 11(12), 2634; https://doi.org/10.3390/w11122634 - 13 Dec 2019
Cited by 19 | Viewed by 5061
Abstract
The assessment of the water scarcity footprint of products emerged as an important step in supporting water management strategies. Among others, the AWARE methodology was published as a consensus-based indicator to perform such an assessment at a watershed level and monthly scale. The [...] Read more.
The assessment of the water scarcity footprint of products emerged as an important step in supporting water management strategies. Among others, the AWARE methodology was published as a consensus-based indicator to perform such an assessment at a watershed level and monthly scale. The need to adopt such a detailed resolution, however, collides with the availability of data, so that general year and country-wide factors are commonly used. The objective of this study is to develop and verify the applicability of 26 crop-specific water scarcity characterization factors to help assess the water scarcity footprint when data and information availability is limited. To do so, a weighted average consumption approach was adopted, starting from local AWARE characterization factors and local crop-specific water consumption. The resulting factors, ranging from 0.19 m3/ton eq for “other perennial crop” in Brunei to 9997 m3/ton eq for “other annual crop” in Mauritania, illustrate the large variability of potential water scarcity impacts. Factors were applied to the water consumption of selected crops to assess their water scarcity footprint. The results of the study confirmed that the use of crop-specific factors is recommended as they are a better proxy of water scarcity in a region when compared to their national generic counterparts. Full article
(This article belongs to the Special Issue Water Footprint and Life Cycle Assessment: Methods and Tools for the Strategic Management of Water Related Impacts)
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15 pages, 2157 KiB  
Article
Analysis and Comprehensive Evaluation of Water Use Efficiency in China
by Wenge Zhang, Xianzeng Du, Anqi Huang and Huijuan Yin
Water 2019, 11(12), 2620; https://doi.org/10.3390/w11122620 - 12 Dec 2019
Cited by 22 | Viewed by 5056
Abstract
Proper water use requires its monitoring and evaluation. An indexes system of overall water use efficiency is constructed here that covers water consumption per 10,000 yuan GDP, the coefficient of effective utilization of irrigation water, the water consumption per 10,000 yuan of industrial [...] Read more.
Proper water use requires its monitoring and evaluation. An indexes system of overall water use efficiency is constructed here that covers water consumption per 10,000 yuan GDP, the coefficient of effective utilization of irrigation water, the water consumption per 10,000 yuan of industrial value added, domestic water consumption per capita of residents, and the proportion of water function zone in key rivers and lakes complying with water-quality standards and is applied to 31 provinces in China. Efficiency is first evaluated by a projection pursuit cluster model. Multidimensional efficiency data are transformed into a low-dimensional subspace, and the accelerating genetic algorithm then optimizes the projection direction, which determines the overall efficiency index. The index reveals great variety in regional water use, with Tianjin, Beijing, Hebei, and Shandong showing highest efficiency. Shanxi, Liaoning, Shanghai, Zhejiang, Henan, Shanxi, and Gansu also use water with high efficiency. Medium efficiency occurs in Inner Mongolia, Jilin, Heilongjiang, Jiangsu, Hainan, Qinghai, Ningxia, and Low efficiency is found for Anhui, Fujian, Jiangxi, Hubei, Hunan, Guangdong, Guangxi, Chongqing, Sichuan, Guizhou, Yunnan, and Xinjiang. Tibet is the least efficient. The optimal projection direction is a* = (0.3533, 0.7014, 0.4538, 0.3315, 0.1217), and the degree of influence of agricultural irrigation efficiency, water consumption per industrial profit, water used per gross domestic product (GDP), domestic water consumption per capita of residents, and environmental water quality on the result has decreased in turn. This may aid decision making to improve overall water use efficiency across China. Full article
(This article belongs to the Section Water Use and Scarcity)
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32 pages, 12206 KiB  
Review
Potential Health Risks Linked to Emerging Contaminants in Major Rivers and Treated Waters
by James Kessler, Diane Dawley, Daniel Crow, Ramin Garmany and Philippe T. Georgel
Water 2019, 11(12), 2615; https://doi.org/10.3390/w11122615 - 11 Dec 2019
Cited by 9 | Viewed by 4786
Abstract
The presence of endocrine-disrupting chemicals (EDCs) in our local waterways is becoming an increasing threat to the surrounding population. These compounds and their degradation products (found in pesticides, herbicides, and plastic waste) are known to interfere with a range of biological functions from [...] Read more.
The presence of endocrine-disrupting chemicals (EDCs) in our local waterways is becoming an increasing threat to the surrounding population. These compounds and their degradation products (found in pesticides, herbicides, and plastic waste) are known to interfere with a range of biological functions from reproduction to differentiation. To better understand these effects, we used an in silico ontological pathway analysis to identify the genes affected by the most commonly detected EDCs in large river water supplies, which we grouped together based on four common functions: Organismal injuries, cell death, cancer, and behavior. In addition to EDCs, we included the opioid buprenorphine in our study, as this similar ecological threat has become increasingly detected in river water supplies. Through the identification of the pleiotropic biological effects associated with both the acute and chronic exposure to EDCs and opioids in local water supplies, our results highlight a serious health threat worthy of additional investigations with a potential emphasis on the effects linked to increased DNA damage. Full article
(This article belongs to the Special Issue Integrated Water Resources Research: Advancements in Understanding to Improve Future Sustainability)
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16 pages, 4484 KiB  
Article
Membrane Fouling and Performance of Flat Ceramic Membranes in the Application of Drinking Water Purification
by Shujuan Meng, Minmin Zhang, Meng Yao, Zhuguo Qiu, Yubin Hong, Weiguang Lan, Haiping Xia and Xue Jin
Water 2019, 11(12), 2606; https://doi.org/10.3390/w11122606 - 10 Dec 2019
Cited by 33 | Viewed by 7170
Abstract
Membrane technologies have been widely applied in surface water treatment for drinking water purification. The main obstacles to the large scale application of membranes include membrane fouling, energy consumption and high investment. This study systematically investigated the performance of a hybrid system including [...] Read more.
Membrane technologies have been widely applied in surface water treatment for drinking water purification. The main obstacles to the large scale application of membranes include membrane fouling, energy consumption and high investment. This study systematically investigated the performance of a hybrid system including in-situ coagulation and membrane module. The key parameters of a membrane system, including initial flux, operation mode (intermediate or continuous, time intervals, backwashing and aeration) was comprehensively investigated. In addition, the treatment performance in terms of turbidity, organic matter removal, membrane fouling and cleaning, and the effect of coagulants, were also studied. It was found that flat ceramic membranes with in-situ coagulation for surface water treatment performed much better without aeration and frequent backwashing, which gave interesting and important implications for future applications of a flat ceramic membrane, especially in drinking water purification. The hybrid system can achieve a high-water flux of 150 L/m2·h (LMH) for 8 h operation without aeration and backwash. The removal of turbidity, UV254 and COD can achieve 99%, 85% and 81%, respectively. The cake layer on the membrane surface formed from the coagulation flocs turned out to prevent the membrane to be exposed to organic pollutant immediately which minimized the fouling problem. In addition, the fouling layer on the membrane surface can be easily cleaned by air scouring and backwash at the end of experiments, with a water flux recovery of higher than 90%. These results in this study provided an alternative strategy for membrane fouling control and energy conservation. Full article
(This article belongs to the Special Issue Membrane Technologies and Water Treatment)
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20 pages, 1721 KiB  
Article
Combining Hydrologic Analysis and Life Cycle Assessment Approaches to Evaluate Sustainability of Water Infrastructure: Uncertainty Analysis
by Hassan Tavakol-Davani, Reyhaneh Rahimi, Steven J. Burian, Christine A. Pomeroy, Brian J. McPherson and Defne Apul
Water 2019, 11(12), 2592; https://doi.org/10.3390/w11122592 - 9 Dec 2019
Cited by 12 | Viewed by 3752
Abstract
The goal of this research is identifying major sources of uncertainty of an environmentally-sustainable urban drainage infrastructure design, based on hydrologic analysis and life cycle assessment (LCA). The uncertainty analysis intends to characterize and compare relative roles of unreliability, incompleteness, technological difference, and [...] Read more.
The goal of this research is identifying major sources of uncertainty of an environmentally-sustainable urban drainage infrastructure design, based on hydrologic analysis and life cycle assessment (LCA). The uncertainty analysis intends to characterize and compare relative roles of unreliability, incompleteness, technological difference, and spatial and temporal variation in life cycle impact assessment (LCIA) data, as well as natural variability in hydrologic data. Uncertainties are analyzed using a robust Monte Carlo simulation approach, performed by High Throughput Computing (HTC) and interpreted by Morse-Scale regression models. The uncertainty analysis platform is applied to a watershed-scale LCA of rainwater harvesting systems (RWH) to control combined sewer overflows (CSOs). To consider the watershed-scale implications, RWH is simulated to serve for both the water supply and CSO control in an urban watershed in Toledo, Ohio, USA. Results suggest that, among the studied parameters, rainfall depth (as a hydrologic parameter) caused more than 86% of the uncertainty, while only 7% of the uncertainty was caused by LCIA parameters. Such an emphasis on the necessity of robust hydrologic data and associated analyses increase the reliability of LCA-based urban water infrastructure design. In addition, results suggest that such a topology-inspired model is capable of rendering an optimal RWH system capacity as a function of annual rainfall depth. Specifically, if the system could capture 1/40th of annual rainfall depth in each event from rooftops, the RWH system would be optimal and, thus, lead to minimized life cycle impacts in terms of global warming potential (GWP) and aquatic eco-toxicity (ETW). This capture depth would be around 2.1 cm for Toledo (given an 85 cm/year rainfall and 200 m2 typical roof area), which could be achieved through an RWH system with 4.25 m3 capacity per household, assuming a uniform plan for the entire studied watershed. Capacities smaller than this suggested optimal value would likely result in loss of RWH potable water treatment savings and CSO control benefits, while capacities larger than the optimal would likely incur an excessive wastewater treatment burden and construction phase impacts of RWH systems. Full article
(This article belongs to the Section Urban Water Management)
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22 pages, 1374 KiB  
Article
Re-Interpreting Cooperation in Transboundary Waters: Bringing Experiences from the Brahmaputra Basin
by Anamika Barua, Arundhati Deka, Vishaka Gulati, Sumit Vij, Xiawei Liao and Halla Maher Qaddumi
Water 2019, 11(12), 2589; https://doi.org/10.3390/w11122589 - 8 Dec 2019
Cited by 15 | Viewed by 10243
Abstract
Several studies have demonstrated the continuum of cooperation on transboundary rivers, but have largely focused on government to government (Track 1) cooperation and formal diplomacy. Formal arrangements like treaties, agreements, joint mechanisms, joint bodies, joint commissions (e.g., river basin organizations), etc., fall within [...] Read more.
Several studies have demonstrated the continuum of cooperation on transboundary rivers, but have largely focused on government to government (Track 1) cooperation and formal diplomacy. Formal arrangements like treaties, agreements, joint mechanisms, joint bodies, joint commissions (e.g., river basin organizations), etc., fall within the scope of transboundary waters cooperation. However, in some transboundary rivers, often due to political constraints, Track 1 cooperation might not be a feasible option. When governmental cooperation is a non-starter, effort and progress made outside the government domain through informal dialogues can play a significant role. It is therefore important to re-examine the definition of cooperation as it applies to international rivers, and potentially to broaden its scope. Such an examination raises important questions: What does international cooperation in this context actually mean? Is it formal (Track 1) cooperation related to sharing of water, data, and information only, or does it have a broader meaning? What, precisely, can be the entry point for such cooperation? Are informal transboundary dialogues and water diplomacy itself an entry point for cooperation on international rivers? This paper aimed to answer these critical questions drawing from the “Brahmaputra Dialogue” project initiated in 2013 under the South Asia Water Initiative (SAWI), which involved the four riparian countries of the Brahmaputra Basin. Several important focal points of cooperation emerged through this sustained dialogue, which went beyond sharing hydrological data or signing a basin-level treaty, broadening the definition of “cooperation”. The paper, bringing evidence from the dialogue, argues that the Brahmaputra Dialogue process has led to a broader understanding of cooperation among basin stakeholders, which could influence water resource management of the basin in the future. Full article
(This article belongs to the Special Issue Managing Water Resources in Large River Basins)
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