Water

27 pages, 4066 KiB

Open AccessEditor’s ChoiceArticle

Unsustainability Syndrome—From Meteorological to Agricultural Drought in Arid and Semi-Arid Regions

by Ali Torabi Haghighi, Nizar Abou Zaki, Pekka M. Rossi, Roohollah Noori, Ali Akbar Hekmatzadeh, Hossein Saremi and Bjørn Kløve

Water 2020, 12(3), 838; https://doi.org/10.3390/w12030838 - 16 Mar 2020

Cited by 63 | Viewed by 6130

Abstract

Water is the most important resource for sustainable agriculture in arid and semi-arid regions, where agriculture is the mainstay for rural societies. By relating the water usage to renewable water resources, we define three stages from sustainable to unsustainable water resources: (1) sustainable, [...] Read more.

Water is the most important resource for sustainable agriculture in arid and semi-arid regions, where agriculture is the mainstay for rural societies. By relating the water usage to renewable water resources, we define three stages from sustainable to unsustainable water resources: (1) sustainable, where water use is matched by renewable water capacity, ensuring sustainable water resources; (2) transitional, where water use occasionally exceeds renewable water capacity; and (3) unsustainable, with lack of water resources for agriculture, society, and the environment. Using available drought indicators (standardized precipitation index (SPI) and streamflow drought index (SDI)) and two new indices for agricultural drought (overall agricultural drought index (OADI) and agricultural drought index (ADI)), we evaluated these stages using the example of Fars province in southern Iran in the period 1977–2016. A hyper-arid climate prevailed for an average of 32% of the province’s spatio-temporal coverage during the study period. The area increased significantly from 30.6% in the first decade (1977–1986) to 44.4% in the last (2006–2015). The spatiotemporal distribution of meteorological drought showed no significant negative trends in annual precipitation during 1977–2016, but the occurrence of hydrological droughts increased significantly in the period 1997–2016. The expansion of irrigated area, with more than 60% of rainfed agriculture replaced by irrigated agriculture (especially between 1997 and 2006), exerted substantial pressure on surface water and groundwater resources. Together, climate change, reduced river flow, and significant declines in groundwater level in major aquifers led to unsustainable use of water resources, a considerable reduction in irrigated area, and unsustainability in agricultural production in the period 2006–2015. Analysis of causes and effects of meteorological, hydrological, and agricultural drought in the area identified three clear stages: before 1997 being sustainable, 1997–2006 being transitional, and after 2006 being unsustainable. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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17 pages, 4274 KiB

Open AccessEditor’s ChoiceArticle

Multi-Objective Approach for Determining Optimal Sustainable Urban Drainage Systems Combination at City Scale. The Case of San Luis Potosí (México)

by Sergio Zubelzu, Leonor Rodríguez-Sinobas, Alvaro Sordo-Ward, Alan Pérez-Durán and Rodolfo Cisneros-Almazán

Water 2020, 12(3), 835; https://doi.org/10.3390/w12030835 - 16 Mar 2020

Cited by 7 | Viewed by 4274

Abstract

A method for determining the optimal Sustainable Urban Drainage Systems (SUDs) combination at city scale is presented in this paper. A comprehensive set of SUDs categories comprising infrastructures aimed at either detaining and locally reusing or infiltrating precipitation are considered. A volumetric water [...] Read more.

A method for determining the optimal Sustainable Urban Drainage Systems (SUDs) combination at city scale is presented in this paper. A comprehensive set of SUDs categories comprising infrastructures aimed at either detaining and locally reusing or infiltrating precipitation are considered. A volumetric water balance is proposed for modelling hydrological processes in urban catchments. A multi-criteria approach combining a cost function and aims for both recharging aquifers and limiting runoff contribution to water courses is proposed to find the optimal SUDs combination. The water balance was run with each possible SUDs combination and the optimal set of SUDs was found. The method was applied to the Metropolitan Area of San Luis Potosí (Mexico). The optimal solutions in this case clearly promoted surface runoff detention and reuse over porous pavements and green roofs but they were sensitive to the considered costs. The SUD requirements to potential new urban developments for each catchment to comply with the original hydrological aims were also studied. The method requires customizing the cost function and using representative climatic data. Full article

(This article belongs to the Special Issue Planning and Management of Hydraulic Infrastructure)

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21 pages, 600 KiB

Open AccessEditor’s ChoiceArticle

Unpacking Water Governance: A Framework for Practitioners

by Alejandro Jiménez, Panchali Saikia, Ricard Giné, Pilar Avello, James Leten, Birgitta Liss Lymer, Kerry Schneider and Robin Ward

Water 2020, 12(3), 827; https://doi.org/10.3390/w12030827 - 15 Mar 2020

Cited by 135 | Viewed by 25194

Abstract

Water governance has emerged as an important topic in the international arena and is acknowledged to be a crucial factor for adequate and sustained progress towards achieving Sustainable Development Goal (SDG) 6. However, there is not enough clarity about the practical meaning of [...] Read more.

Water governance has emerged as an important topic in the international arena and is acknowledged to be a crucial factor for adequate and sustained progress towards achieving Sustainable Development Goal (SDG) 6. However, there is not enough clarity about the practical meaning of the term “water governance” and how to work with it. This paper reviews the term’s use, to reveal how the concept is understood, referred to, and implemented in practice by different stakeholders. Based on literature review and consultations with experts, we identify and describe the core components of water governance (functions), describe their potential qualities when performed (attributes), and how they interrelate with the values and aspirations of the different stakeholders to achieve certain outcomes. These different components are described in detail to construct an operational framework to assess and work with water governance, which covers water and sanitation services delivery, water resources management and transboundary waters. This paper’s findings provide practical guidance for decision makers and practitioners on how action-oriented water governance processes can be meaningfully designed, and ultimately, how to strengthen efforts aiming to improve water governance. Full article

(This article belongs to the Special Issue Selected Papers from 2019 World Water Week)

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16 pages, 3376 KiB

Open AccessEditor’s ChoiceArticle

A Nonlinear Autoregressive Modeling Approach for Forecasting Groundwater Level Fluctuation in Urban Aquifers

by Abdullah A. Alsumaiei

Water 2020, 12(3), 820; https://doi.org/10.3390/w12030820 - 14 Mar 2020

Cited by 49 | Viewed by 4920

Abstract

The application of a nonlinear autoregressive modeling approach with exogenous input (NARX) neural networks for modeling groundwater level fluctuation has been examined by several researchers. However, the suitability of NARX in modeling groundwater level dynamics in urbanized and arid aquifer systems has not [...] Read more.

The application of a nonlinear autoregressive modeling approach with exogenous input (NARX) neural networks for modeling groundwater level fluctuation has been examined by several researchers. However, the suitability of NARX in modeling groundwater level dynamics in urbanized and arid aquifer systems has not been comprehensively investigated. In this study, a NARX-based modeling approach is presented to establish a robust water management tool to aid urban water managers in controlling the development of shallow water tables induced by artificial recharge activity. Temperature data series are used as exogenous inputs for the NARX network, as they better reflect the intensity of artificial recharge activities, such as excessive lawns irrigation. Input delays and feedback delays for the NARX networks are determined based on the autocorrelation and cross-correlation analyses of detrended groundwater levels and monthly temperature averages. The validation of the proposed approach is assessed through a rolling validation procedure. Four observation wells in Kuwait City are selected to test the applicability of the proposed approach. The results showed the superiority of the NARX-based approach in modeling groundwater levels in such an urbanized and arid aquifer system, with coefficient of determination (R²) values ranging between 0.762 and 0.994 in the validation period. Comparison with other statistical models applied to the same study area shows that NARX models presented here reduced the mean absolute error (MAE) of groundwater levels forecasts by 50%. The findings of this paper are promising and provide a valuable tool for the urban city planner to assist in controlling the problem of shallow water tables for similar climatic and aquifer systems. Full article

(This article belongs to the Section Urban Water Management)

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23 pages, 3266 KiB

Open AccessEditor’s ChoiceArticle

Lithological and Tectonic Control on Groundwater Contribution to Stream Discharge During Low-Flow Conditions

by Stefanie B. Wirth, Claire Carlier, Fabien Cochand, Daniel Hunkeler and Philip Brunner

Water 2020, 12(3), 821; https://doi.org/10.3390/w12030821 - 14 Mar 2020

Cited by 17 | Viewed by 5187

Abstract

Knowing how stream discharge in an ungauged catchment reacts to dry spells is a major challenge for managing water resources. The role of geology on these dynamics is poorly understood. For the Swiss Molasse basin, we therefore explored how the geology influences the [...] Read more.

Knowing how stream discharge in an ungauged catchment reacts to dry spells is a major challenge for managing water resources. The role of geology on these dynamics is poorly understood. For the Swiss Molasse basin, we therefore explored how the geology influences the groundwater contribution to stream flow during low-flow conditions. Using existing data from geological reports and maps as well as from deep boreholes, we constructed a basin-wide overview of the hydrogeological quality of the bedrock and investigated five catchments in 3D. We found that catchments with the most permeable sedimentary bedrock are least sensitive to low flows (marine sandstone, K = 10⁻⁴ to 10⁻⁵ m/s, P_eff = 5–10%). In contrast, if bedrock K is low (K < 10⁻⁶ m/s), the presence of a productive Quaternary volume becomes decisive for groundwater contribution to stream flow. Limitations exist due to a restricted database for K and P_eff values of the Molasse and limited information on continuation of lithologies with depth. This emphasizes the need for more hydrogeologically relevant data for the future management of water resources. Our results highlighting what lithotypes favor groundwater contribution to stream flow are valid also in other regions for the assessment of a catchment’s sensitivity to low flows. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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16 pages, 2743 KiB

Open AccessEditor’s ChoiceArticle

Quantile Mapping Bias Correction on Rossby Centre Regional Climate Models for Precipitation Analysis over Kenya, East Africa

by Brian Ayugi, Guirong Tan, Niu Ruoyun, Hassen Babaousmail, Moses Ojara, Hanggoro Wido, Lucia Mumo, Nadoya Hamida Ngoma, Isaac Kwesi Nooni and Victor Ongoma

Water 2020, 12(3), 801; https://doi.org/10.3390/w12030801 - 13 Mar 2020

Cited by 49 | Viewed by 8030

Abstract

This study uses the quantile mapping bias correction (QMBC) method to correct the bias in five regional climate models (RCMs) from the latest output of the Rossby Center Climate Regional Model (RCA4) over Kenya. The outputs were validated using various scalar metrics such [...] Read more.

This study uses the quantile mapping bias correction (QMBC) method to correct the bias in five regional climate models (RCMs) from the latest output of the Rossby Center Climate Regional Model (RCA4) over Kenya. The outputs were validated using various scalar metrics such as root-mean-square difference (RMSD), mean absolute error (MAE), and mean bias. The study found that the QMBC algorithm demonstrates varying performance among the models in the study domain. The results show that most of the models exhibit reasonable improvement after corrections at seasonal and annual timescales. Specifically, the European Community Earth-System (EC-EARTH) and Commonwealth Scientific and Industrial Research Organization (CSIRO) models depict remarkable improvement as compared to other models. On the contrary, the Institute Pierre Simon Laplace Model CM5A-MR (IPSL-CM5A-MR) model shows little improvement across the rainfall seasons (i.e., March–May (MAM) and October–December (OND)). The projections forced with bias-corrected historical simulations tallied observed values demonstrate satisfactory simulations as compared to the uncorrected RCMs output models. This study has demonstrated that using QMBC on outputs from RCA4 is an important intermediate step to improve climate data before performing any regional impact analysis. The corrected models may be used in projections of drought and flood extreme events over the study area. Full article

(This article belongs to the Section Hydrology)

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16 pages, 2086 KiB

Open AccessEditor’s ChoiceArticle

Influence of Local Habitat and Climatic Factors on the Distribution of Fish Species in the Tonle Sap Lake

by Bunyeth Chan, Sébastien Brosse, Zeb S. Hogan, Peng Bun Ngor and Sovan Lek

Water 2020, 12(3), 786; https://doi.org/10.3390/w12030786 - 12 Mar 2020

Cited by 22 | Viewed by 7594

Abstract

Tonle Sap Lake (TSL) is a highly productive system and hosts a high fish diversity and is of paramount importance for sustaining protein supply for over 15 million Cambodians. Nevertheless, the ecology and factors influencing the spatial distribution of many fishes within the [...] Read more.

Tonle Sap Lake (TSL) is a highly productive system and hosts a high fish diversity and is of paramount importance for sustaining protein supply for over 15 million Cambodians. Nevertheless, the ecology and factors influencing the spatial distribution of many fishes within the lake remain poorly understood. Using commercial fishing lot catch data from 1994/1995 to 1999/2000, fishing seasons and environmental data (land cover and bioclimatic variables), we describe spatial distribution of the eight most commercially important fish species, and investigate the effects of environmental factors on their distributions in the TSL. We found a strong variability in fish biomass across areas and between species. Specifically, Channa micropeltes was most abundant in the southern and northern sections of the TSL. Channa striata and Trichopodus microlepis were more common in the northern part of the TSL. Cyclocheilos enoplos, Barbonymus gonionotus, Pangasianodon hypophthalmus, and Gymnostomus spp. were abundant in the southern areas of the TSL while Phalacronotus spp. were abundant in few areas in both the north and the south. Flooded forest positively explained the variation in the biomass of P. hypophthalmus, C. striata, C. enopolos, and Phalacronotus spp. Likewise, the lake’s open water positively affects the biomass of P. hypophthalmus, C. enopolos, and Phalacronotus spp., while the agricultural field negatively impacts Gymnostomus spp. biomass distribution. We also found that some areas consistently hosted high fish biomass (e.g., lot 2, Kampong Thom; lot 6, Pursat; lot 2, Battambang, etc.). We, therefore, suggest that fisheries management and conservation planning focus on those areas, considering those areas significance as core fish habitat and important for catching fish. Full article

(This article belongs to the Special Issue Channels for Change: Integrating Multiple Disciplines for New Frontiers in Managing the Mekong River Basin)

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32 pages, 4941 KiB

Open AccessEditor’s ChoiceArticle

Using the Freshwater Health Index to Assess Hydropower Development Scenarios in the Sesan, Srepok and Sekong River Basin

by Nicholas J. Souter, Kashif Shaad, Derek Vollmer, Helen M. Regan, Tracy A. Farrell, Mike Arnaiz, Peter-John Meynell, Thomas A. Cochrane, Mauricio E. Arias, Thanapon Piman and Sandy J. Andelman

Water 2020, 12(3), 788; https://doi.org/10.3390/w12030788 - 12 Mar 2020

Cited by 14 | Viewed by 8550

Abstract

Sustainable water resource management is a wicked problem, fraught with uncertainties, an indeterminate scope, and divergent social values and interests among stakeholders. To facilitate better management of Southeast Asia’s transboundary Sesan, Sekong and Srepok (3S) River basin, we used the Freshwater Health Index [...] Read more.

Sustainable water resource management is a wicked problem, fraught with uncertainties, an indeterminate scope, and divergent social values and interests among stakeholders. To facilitate better management of Southeast Asia’s transboundary Sesan, Sekong and Srepok (3S) River basin, we used the Freshwater Health Index (FHI) to diagnose the basin’s current and likely future level of freshwater health. We used the conditions for December 2016 as a baseline, where Ecosystem Vitality and Ecosystem Services scored 66 and 80, respectively, out of a possible 100, whilst Governance & Stakeholders scored 43. Thus, the 3S provided a range of desired ecosystem services, but there were signs of environmental stress as well as undeveloped water governance systems and limited stakeholder engagement. We also modelled four hydropower development scenarios and found that increasing development reduced the scores of a subset of indicators. This compromised the future ability of the 3S basin’s ecosystem to provide its current range of services. The FHI helped identify data deficiencies, illuminated important social dynamics, made ecosystem–human–water dynamics more understandable to stakeholders, and examined the long-term dynamics of the basin. Full article

(This article belongs to the Special Issue Channels for Change: Integrating Multiple Disciplines for New Frontiers in Managing the Mekong River Basin)

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18 pages, 2685 KiB

Open AccessEditor’s ChoiceArticle

Net Ecosystem Production of a River Relying on Hydrology, Hydrodynamics and Water Quality Monitoring Stations

by Fernando Rojano, David H Huber, Ifeoma R Ugwuanyi, Vadesse Lhilhi Noundou, Andrielle Larissa Kemajou-Tchamba and Jesus E Chavarria-Palma

Water 2020, 12(3), 783; https://doi.org/10.3390/w12030783 - 12 Mar 2020

Cited by 5 | Viewed by 4615

Abstract

Flow and water quality of rivers are highly dynamic. Water quantity and quality are subjected to simultaneous physical, chemical and biological processes making it difficult to accurately assess lotic ecosystems. Our study investigated net ecosystem production (NEP) relying on high-frequency data of hydrology, [...] Read more.

Flow and water quality of rivers are highly dynamic. Water quantity and quality are subjected to simultaneous physical, chemical and biological processes making it difficult to accurately assess lotic ecosystems. Our study investigated net ecosystem production (NEP) relying on high-frequency data of hydrology, hydrodynamics and water quality. The Kanawha River, West Virginia was investigated along 52.8 km to estimate NEP. Water quality data were collected along the river using three distributed multiprobe sondes that measured water temperature, dissolved oxygen, dissolved oxygen saturation, specific conductance, turbidity and ORP hourly for 71 days. Flows along the river were predicted by means of the hydrologic and hydrodynamic models in Hydrologic Simulation Program in Fortran (HSPF). It was found that urban local inflows were correlated with NEP. However, under hypoxic conditions, local inflows were correlated with specific conductance. Thus, our approach represents an effort for the systematic integration of data derived from models and field measurements with the aim of providing an improved assessment of lotic ecosystems. Full article

(This article belongs to the Special Issue Integrated Water Resources Research: Advancements in Understanding to Improve Future Sustainability)

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19 pages, 4455 KiB

Open AccessEditor’s ChoiceArticle

Trend in Extreme Precipitation Indices Based on Long Term In Situ Precipitation Records over Pakistan

by Asher Samuel Bhatti, Guojie Wang, Waheed Ullah, Safi Ullah, Daniel Fiifi Tawia Hagan, Isaac Kwesi Nooni, Dan Lou and Irfan Ullah

Water 2020, 12(3), 797; https://doi.org/10.3390/w12030797 - 12 Mar 2020

Cited by 84 | Viewed by 8677

Abstract

Assessing the long-term precipitation changes is of utmost importance for understanding the impact of climate change. This study investigated the variability of extreme precipitation events over Pakistan on the basis of daily precipitation data from 51 weather stations from 1980-2016. The non-parametric Mann–Kendall, [...] Read more.

Assessing the long-term precipitation changes is of utmost importance for understanding the impact of climate change. This study investigated the variability of extreme precipitation events over Pakistan on the basis of daily precipitation data from 51 weather stations from 1980-2016. The non-parametric Mann–Kendall, Sen’s slope estimator, least squares method, and two-tailed simple t-test methods were used to assess the trend in eight precipitation extreme indices. These indices were wet days (R1 ≥1 mm), heavy precipitation days (R10 ≥ 10 mm), very heavy precipitation days (R20 ≥ 20 mm), severe precipitation (R50 ≥ 50 mm), very wet days (R95p) defining daily precipitation ≥ 95 percentile, extremely wet days (R99p) defining daily precipitation ≥ 99 percentile, annual total precipitation in wet days (PRCPTOT), and mean precipitation amount on wet days as simple daily intensity index (SDII). The study is unique in terms of using high stations’ density, extended temporal coverage, advanced statistical techniques, and additional extreme indices. Furthermore, this study is the first of its kind to detect abrupt changes in the temporal trend of precipitation extremes over Pakistan. The results showed that the spatial distribution of trends in different precipitation extreme indices over the study region increased as a whole; however, the monsoon and westerlies humid regions experienced a decreasing trend of extreme precipitation indices during the study period. The results of the sequential Mann–Kendall (SqMK) test showed that all precipitation extremes exhibited abrupt dynamic changes in temporal trend during the study period; however, the most frequent mutation points with increasing tendency were observed during 2011 and onward. The results further illustrated that the linear trend of all extreme indices showed an increasing tendency from 1980- 2016. Similarly, for elevation, most of the precipitation extremes showed an inverse relationship, suggesting a decrease of precipitation along the latitudinal extent of the country. The spatiotemporal variations in precipitation extremes give a possible indication of the ongoing phenomena of climate change and variability that modified the precipitation regime of Pakistan. On the basis of the current findings, the study recommends that future studies focus on underlying physical and natural drivers of precipitation variability over the study region. Full article

(This article belongs to the Section Water Use and Scarcity)

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16 pages, 2427 KiB

Open AccessEditor’s ChoiceArticle

Treatment of Produced Water in the Permian Basin for Hydraulic Fracturing: Comparison of Different Coagulation Processes and Innovative Filter Media

by Alfredo Zendejas Rodriguez, Huiyao Wang, Lei Hu, Yanyan Zhang and Pei Xu

Water 2020, 12(3), 770; https://doi.org/10.3390/w12030770 - 11 Mar 2020

Cited by 69 | Viewed by 10139

Abstract

Produced water is the largest volume of waste product generated during oil and natural gas exploration and production. The traditional method to dispose of produced water involves deep well injection, but this option is becoming more challenging due to high operational cost, limited [...] Read more.

Produced water is the largest volume of waste product generated during oil and natural gas exploration and production. The traditional method to dispose of produced water involves deep well injection, but this option is becoming more challenging due to high operational cost, limited disposal capacity, and more stringent regulations. Meanwhile, large volumes of freshwater are used for hydraulic fracturing. The goal of this study is to develop cost-effective technologies, and optimize system design and operation to treat highly saline produced water (120–140 g/L total dissolved solids) for hydraulic fracturing. Produced water was collected from a salt water disposal facility in the Permian Basin, New Mexico. Chemical coagulation (CC) using ferric chloride and aluminum sulfate as coagulants was compared with electrocoagulation (EC) with aluminum electrodes for removal of suspended contaminants. The effects of coagulant dose, current density, and hydraulic retention time during EC on turbidity removal were investigated. Experimental results showed that aluminum sulfate was more efficient and cost-effective than ferric chloride for removing turbidity from produced water. The optimal aluminum dose was achieved at operating current density of 6.60 mA/cm² and 12 min contact time during EC treatment, which resulted in 74% removal of suspended solids and 53–78% removal of total organic carbon (TOC). The energy requirement of EC was calculated 0.36 kWh/m³ of water treated. The total operating cost of EC was estimated $0.44/m³ of treated water, which is 1.7 or 1.2 times higher than CC using alum or ferric chloride as the coagulant, respectively. The EC operating cost was primarily associated with the consumption of aluminum electrode materials due to faradaic reactions and electrodes corrosions. EC has the advantage of shorter retention time, in situ production of coagulants, less sludge generation, and high mobility for onsite produced water treatment. The fine particles and other contaminants after coagulation were further treated in continuous-flow columns packed with different filter media, including agricultural waste products (pecan shell, walnut shell, and biochar), and new and spent granular activated carbon (GAC). Turbidity, TOC, metals, and electrical conductivity were monitored to evaluate the performance of the treatment system and the adsorption capacities of different media. Biochar and GAC showed the greatest removal of turbidity and TOC in produced water. These treatment technologies were demonstrated to be effective for the removal of suspended constituents and iron, and to produce a clean brine for onsite reuse, such as hydraulic fracturing. Full article

(This article belongs to the Special Issue Advanced Technologies for Produced Water Management, Treatment, and Reuse)

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24 pages, 9625 KiB

Open AccessEditor’s ChoiceArticle

Addressing the Water–Energy Nexus by Coupling the Hydrological Model with a New Energy LISENGY Model: A Case Study in the Iberian Peninsula

by Marko Adamovic, Emiliano Gelati, Berny Bisselink and Ad De Roo

Water 2020, 12(3), 762; https://doi.org/10.3390/w12030762 - 10 Mar 2020

Cited by 3 | Viewed by 3785

Abstract

As water is required for producing hydropower, and subsequently the water balance is changed for downstream areas, the linking of hydrological and energy models is needed to properly address the interactions among them. In this study, volume–depth-based water storage estimation models were proposed [...] Read more.

As water is required for producing hydropower, and subsequently the water balance is changed for downstream areas, the linking of hydrological and energy models is needed to properly address the interactions among them. In this study, volume–depth-based water storage estimation models were proposed for individual lakes and reservoirs in the Iberian Peninsula using the 30-year Global Water Surface dataset and reservoir morphometry methodology which enables to evaluate reservoirs where data were not available before. The models were subsequently implemented within the new hydropower model called LISENGY that provides the first comprehensive assessment of the temporal and spatial dynamics of water storage, water depth and hydropower production in the Iberian Peninsula. The LISENGY model was coupled with the distributed LISFLOOD hydrological model. The seasonal and interannual changes in energy production were assessed for 168 studied reservoirs with diverse morphometries, which is unique. Conical, concave and convex regression reservoir relationships were distinguished, and optimized turbine discharge and power production were computed. A 10-year water–energy linked system for the 2007–2016 period has been established for the Iberian Peninsula which was not available before. The results showed that it is possible to connect those two models and that the timing and magnitude of simulated storage were well reproduced. The study represents the first step towards integrated pan-European water–energy modeling. Future climate scenarios and energy demands are to be fed into the linked model system to evaluate expected future hydropower generation and possible water scarcity issues. Full article

(This article belongs to the Section Water, Agriculture and Aquaculture)

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36 pages, 2603 KiB

Open AccessEditor’s ChoiceArticle

Assessment of Water Security in Socially Excluded Areas in Kolkata, India: An Approach Focusing on Water, Sanitation and Hygiene

by Subham Mukherjee, Trude Sundberg and Brigitta Schütt

Water 2020, 12(3), 746; https://doi.org/10.3390/w12030746 - 8 Mar 2020

Cited by 24 | Viewed by 14774

Abstract

Water security is essential not only to ensure the availability and accessibility of water for drinking, producing food, washing, but also to maintain both human and environmental health. The 2011 Census of India reveals that 17.4% of urban households in India live in [...] Read more.

Water security is essential not only to ensure the availability and accessibility of water for drinking, producing food, washing, but also to maintain both human and environmental health. The 2011 Census of India reveals that 17.4% of urban households in India live in deprived areas in urban landscapes which are designated as slums in the Census dataset. The increasing number of people living in these areas poses serious challenges to the provision of basic urban water, sanitation and hygiene (WaSH) services. Perceived susceptibility of risks from contaminated water and lack of proper sanitation and hygiene will be addressed in the light of social exclusion factors. This study attempts to assess the present situation of water, sanitation and required hygiene provisions within the areas defined as slums by the Census of India 2011 in Kolkata, India. Based on the results obtained from the datasets from the census, and a household survey, we identified a lack of supplies associated with WaSH provisions in these areas of Kolkata. The WaSH provisions in the slum areas of Kolkata city are facing various issues related to regularity, quality and quantity of supplied water. Additionally, there is poor maintenance of existing WaSH services including latrine facilities and per capita allocation of a sustainable water security among the slum dwellers. By adding to our understanding of the importance of factors such as gender, religions, and knowledge of drinking water in deprived areas, the study analyses the links between both physical and social issues determining vulnerability and presence of deprivation associated with basic WaSH provisions as human rights of slum communities. Full article

(This article belongs to the Section Urban Water Management)

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17 pages, 4260 KiB

Open AccessEditor’s ChoiceArticle

New Sustainable Approach for the Production of Fe₃O₄/Graphene Oxide-Activated Persulfate System for Dye Removal in Real Wastewater

by Md. Nahid Pervez, Wei He, Tiziano Zarra, Vincenzo Naddeo and Yaping Zhao

Water 2020, 12(3), 733; https://doi.org/10.3390/w12030733 - 7 Mar 2020

Cited by 91 | Viewed by 7684

Abstract

Persulfate (PS)-activated, iron-based heterogeneous catalysts have attracted significant attention as a potential advanced and sustainable water purification system. Herein, a novel Fe₃O₄ impregnated graphene oxide (Fe₃O₄@GO)-activated persulfate system (Fe₃O₄@GO+K₂S₂ [...] Read more.

Persulfate (PS)-activated, iron-based heterogeneous catalysts have attracted significant attention as a potential advanced and sustainable water purification system. Herein, a novel Fe₃O₄ impregnated graphene oxide (Fe₃O₄@GO)-activated persulfate system (Fe₃O₄@GO+K₂S₂O₈) was synthesized by following a sustainable protocol and was tested on real wastewater containing dye pollutants. In the presence of the PS-activated system, the degradation efficiency of Rhodamine B (RhB) was significantly increased to a level of ≈95% compared with that of Fe₃O₄ (≈25%). The influences of different operational parameters, including solution pH, persulfate dosage, and RhB concentration, were systemically evaluated. This system maintained its catalytic activity and durability with a negligible amount of iron leached during successive recirculation experiments. The degradation intermediates were further identified through reactive oxygen species (ROS) studies, where surface-bound SO₄⁻ was found to be dominant radical for RhB degradation. Moreover, the degradation mechanism of RhB in the Fe₃O₄@GO+K₂S₂O₈ system was discussed. Finally, the results indicate that the persulfate-activated Fe₃O₄@GO catalyst provided an effective pathway for the degradation of dye pollutants in real wastewater treatment. Full article

(This article belongs to the Section Wastewater Treatment and Reuse)

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17 pages, 5700 KiB

Open AccessEditor’s ChoiceArticle

A New Approach to Permeability Inversion of Fractured Rock Masses and Its Engineering Application

by Lei Gan, Guanyun Chen and Zhenzhong Shen

Water 2020, 12(3), 734; https://doi.org/10.3390/w12030734 - 7 Mar 2020

Cited by 14 | Viewed by 3740

Abstract

This paper presents a new seepage inversion technique to predict the permeability coefficient of the rock mass with developed fracture or fault. With the measured data of flow and water head of boreholes, the permeability coefficient of the rock masses near the boreholes [...] Read more.

This paper presents a new seepage inversion technique to predict the permeability coefficient of the rock mass with developed fracture or fault. With the measured data of flow and water head of boreholes, the permeability coefficient of the rock masses near the boreholes are obtained by inverse calculation on the basis of unsteady seepage tests. Then, a flexible tolerance method is proposed to invert the permeability coefficient of rock masses in different zones of the reservoir area. This comprehensive inversion analysis method is applied in one actual project of the water supply reservoir. The equivalent permeability coefficient of the rock masses in the range of 0 m to 16.0 m below the road surface near the dam axis on the left bank of the mountain is 1.12 × 10⁻³ cm/s. The root mean squared error and coefficient of determination of the measured and calculated values are 1.33 × 10⁻⁴ m³/s and 0.9976 m³/s, respectively. The rock masses in the reservoir site area have high permeability. The groundwater level in the junction area and the mountains on both sides of Shangmo reservoir is low, and the hydraulic gradient is small. The maximum error between the calculated value of the groundwater level and the measured values is −0.41 m, and the relative error is −4.36%. The recommended anti-seepage scheme can effectively solve the problem of large leakage in the reservoir area. The results show that the innovative approach is appropriate for the seepage analysis of the field with the fractured rock masses and more meaningful from an engineering point of view. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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13 pages, 4708 KiB

Open AccessEditor’s ChoiceArticle

Effect of Pressure Fluctuations and Flow Confinement on Shear Stress in Jet-Driven Scour Processes

by Simone Pagliara and Michele Palermo

Water 2020, 12(3), 718; https://doi.org/10.3390/w12030718 - 6 Mar 2020

Cited by 4 | Viewed by 3005

Abstract

The effect of pressure fluctuations and flow confinement on shear stress still represents a challenging problem for hydraulic engineers. Only a few studies investigated such aspects, but they did not focus on jet-driven scour processes in granular bed material. Following a recent theoretical [...] Read more.

The effect of pressure fluctuations and flow confinement on shear stress still represents a challenging problem for hydraulic engineers. Only a few studies investigated such aspects, but they did not focus on jet-driven scour processes in granular bed material. Following a recent theoretical framework, this paper presents a novel analytical procedure to assess the effect of pressure fluctuations on the average shear stress for 2D equilibrium configuration, under steady, black water flow conditions. The analysis of experimental data evidences that published formulas underestimate the maximum shear stress, because of the significant flow confinement and the presence of rotating material in the scour hole. Therefore, based on the hydrodynamic similitude characterizing the jet diffusion in a confined environment, a new shear stress coefficient and a novel equation are proposed to estimate the maximum shear stress for the tested configuration. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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24 pages, 2731 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Water Regulation in Cyanobacterial Biocrusts from Drylands: Negative Impacts of Anthropogenic Disturbance

by Yolanda Cantón, Sonia Chamizo, Emilio Rodriguez-Caballero, Roberto Lázaro, Beatriz Roncero-Ramos, José Raúl Román and Albert Solé-Benet

Water 2020, 12(3), 720; https://doi.org/10.3390/w12030720 - 6 Mar 2020

Cited by 60 | Viewed by 5503

Abstract

Arid and semi-arid ecosystems are characterized by patchy vegetation and variable resource availability. The interplant spaces of these ecosystems are very often covered by cyanobacteria-dominated biocrusts, which are the primary colonizers of terrestrial ecosystems and key in facilitating the succession of other biocrust [...] Read more.

Arid and semi-arid ecosystems are characterized by patchy vegetation and variable resource availability. The interplant spaces of these ecosystems are very often covered by cyanobacteria-dominated biocrusts, which are the primary colonizers of terrestrial ecosystems and key in facilitating the succession of other biocrust organisms and plants. Cyanobacterial biocrusts regulate the horizontal and vertical fluxes of water, carbon and nutrients into and from the soil and play crucial hydrological, geomorphological and ecological roles in these ecosystems. In this paper, we analyze the influence of cyanobacterial biocrusts on water balance components (infiltration-runoff, evaporation, soil moisture and non-rainfall water inputs (NRWIs)) in representative semiarid ecosystems in southeastern Spain. The influence of cyanobacterial biocrusts, in two stages of their development, on runoff-infiltration was studied by rainfall simulation and in field plots under natural rainfall at different spatial scales. Results showed that cover, exopolysaccharide content, roughness, organic carbon, total nitrogen, available water holding capacity, aggregate stability, and other properties increased with the development of the cyanobacterial biocrust. Due to the effects on these soil properties, runoff generation was lower in well-developed than in incipient-cyanobacterial biocrusts under both simulated and natural rainfall and on different spatial scales. Runoff yield decreased at coarser spatial scales due to re-infiltration along the hillslope, thus decreasing hydrological connectivity. Soil moisture monitoring at 0.03 m depth revealed higher moisture content and slower soil water loss in plots covered by cyanobacterial biocrusts compared to bare soils. Non-rainfall water inputs were also higher under well-developed cyanobacterial biocrusts than in bare soils. Disturbance of cyanobacterial biocrusts seriously affected the water balance by increasing runoff, decreasing soil moisture and accelerating soil water loss, at the same time that led to a very significant increase in sediment yield. The recovery of biocrust cover after disturbance can be relatively fast, but its growth rate is strongly conditioned by microclimate. The results of this paper show the important influence of cyanobacterial biocrust in modulating the different processes supporting the capacity of these ecosystems to provide key services such as water regulation or erosion control, and also the important impacts of their anthropic disturbance. Full article

(This article belongs to the Special Issue Soil and Water-Related Ecosystem Services)

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18 pages, 3713 KiB

Open AccessEditor’s ChoiceArticle

Comparing the Adsorption Performance of Multiwalled Carbon Nanotubes Oxidized by Varying Degrees for Removal of Low Levels of Copper, Nickel and Chromium(VI) from Aqueous Solutions

by Marko Šolić, Snežana Maletić, Marijana Kragulj Isakovski, Jasmina Nikić, Malcolm Watson, Zoltan Kónya and Jelena Tričković

Water 2020, 12(3), 723; https://doi.org/10.3390/w12030723 - 6 Mar 2020

Cited by 43 | Viewed by 3986

Abstract

Functionalized multiwalled carbon nanotubes (MWCNTs) have drawn wide attention in recent years as novel materials for the removal of heavy metals from the aquatic media. This paper investigates the effect that the functionalization (oxidation) process duration time (3 h or 6 h) has [...] Read more.

Functionalized multiwalled carbon nanotubes (MWCNTs) have drawn wide attention in recent years as novel materials for the removal of heavy metals from the aquatic media. This paper investigates the effect that the functionalization (oxidation) process duration time (3 h or 6 h) has on the ability of MWCNTs to treat water contaminated with low levels of Cu(II), Ni(II) and Cr(VI) (initial concentrations 0.5–5 mg L⁻¹) and elucidates the adsorption mechanisms involved. Adsorbent characterization showed that the molar ratio of C and O in these materials was slightly lower for the oxMWCNT6h, due to the higher degree of oxidation, but the specific surface areas and mesopore volumes of these materials were very similar, suggesting that prolonging the functionalization duration had an insignificant effect on the physical characteristics of oxidized multiwalled carbon nanotubes (oxMWCNTs). Increasing the Ph of the solutions from Ph 2 to Ph 8 had a large positive impact on the removal of Cu(II) and Ni(II) by oxMWCNT, but reduced the adsorption of Cr(VI). However, the ionic strength of the solutions had far less pronounced effects. Coupled with the results of fitting the kinetics data to the Elowich and Weber–Morris models, we conclude that adsorption of Cu(II) and Ni(II) is largely driven by electrostatic interactions and surface complexation at the interface of the adsorbate/adsorbent system, whereas the slower adsorption of Cr(VI) on the oxMWCNTs investigated is controlled by an additional chemisorption step where Cr(VI) is reduced to Cr(III). Both oxMWCNT3h and oxMWCNT6h have high adsorption affinities for the heavy metals investigated, with adsorption capacities (expressed by the Freundlich coefficient K_F) ranging from 1.24 to 13.2 (mg g⁻¹)/(mg l⁻¹)ⁿ, highlighting the great potential such adsorbents have in the removal of heavy metals from aqueous solutions. Full article

(This article belongs to the Special Issue Advances in In Situ Biological and Chemical Groundwater Treatment)

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16 pages, 3142 KiB

Open AccessEditor’s ChoiceArticle

Flow Resistance Equation in Sand-bed Rivers and Its Practical Application in the Yellow River

by Rongrong Cai, Hongwu Zhang, Yu Zhang, Luohao Zhang and Hai Huang

Water 2020, 12(3), 727; https://doi.org/10.3390/w12030727 - 6 Mar 2020

Cited by 5 | Viewed by 4474

Abstract

To fully reflect the effect of the flow characteristics, sidewall conditions and sediment concentrations on the bed roughness of sand-bed rivers, this study established a new flow resistance equation by introducing a comprehensive influence coefficient presented via a combination of power-function forms of [...] Read more.

To fully reflect the effect of the flow characteristics, sidewall conditions and sediment concentrations on the bed roughness of sand-bed rivers, this study established a new flow resistance equation by introducing a comprehensive influence coefficient presented via a combination of power-function forms of the relative flow velocity, von Karman constant of sediment-laden flows and the ratio of particle size to viscous sublayer thickness. The comprehensive influence coefficient accordingly acts as a synthesized factor representing the combined effects of the flow intensity, bed material movement, energy consumption condition, and relative friction condition in the near-wall region of sediment-laden flows. Based on the field data from sediment-laden flows under scenarios of both high and low sediment concentrations, the performance of the proposed equation was validated to achieve the best accuracy in the calculation of Manning’s roughness coefficient compared with that of several previously presented flow resistance equations. Furthermore, the proposed flow resistance equation was adopted to quantify the stable channel width of the Lower Yellow River (LYR), i.e., the optimum main channel width for sediment transportation in the typical wandering reach of the LYR. The calculated stable channel width is consistent with the current river training width of the LYR, indicating that the proposed equation has great potential as a theoretical tool that can be used to support the determination of the river training strategy for the LYR. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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20 pages, 2440 KiB

Open AccessEditor’s ChoiceArticle

Zooplankton Community Responses to Oxygen Stress

by Maciej Karpowicz, Jolanta Ejsmont-Karabin, Joanna Kozłowska, Irina Feniova and Andrew R. Dzialowski

Water 2020, 12(3), 706; https://doi.org/10.3390/w12030706 - 5 Mar 2020

Cited by 61 | Viewed by 8049

Abstract

Recent changes in climate and eutrophication have caused increases in oxygen depletion in both freshwater and marine ecosystems. However, the impact of oxygen stress on zooplankton, which is the major trophic link between primary producers and fish, remains largely unknown in lakes. Therefore, [...] Read more.

Recent changes in climate and eutrophication have caused increases in oxygen depletion in both freshwater and marine ecosystems. However, the impact of oxygen stress on zooplankton, which is the major trophic link between primary producers and fish, remains largely unknown in lakes. Therefore, we studied 41 lakes with different trophic and oxygen conditions to assess the role of oxygen stress on zooplankton communities and carbon transfer between phytoplankton and zooplankton. Samples were collected from each lake at the peak of summer stratification from three depth layers (the epilimnion, metalimnion, and hypolimnion). Our results revealed that freshwater zooplankton were relatively tolerant to anoxic conditions and the greatest changes in community structure were found in lakes with the highest oxygen deficits. This caused a switch in dominance from large to small species and reduced the zooplankton biomass in lower, anoxic layers of water, but not in the upper layers of water where the oxygen deficits began. This upper anoxic layer could thus be a very important refuge for zooplankton to avoid predation during the day. However, the reduction of zooplankton in the lower water layers was the main factor that reduced the effectiveness of carbon transfer between the phytoplankton and zooplankton. Full article

(This article belongs to the Special Issue The Response of the Plankton Community to Environmental Stress)

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15 pages, 2326 KiB

Open AccessEditor’s ChoiceArticle

Modeling of the Free-Surface-Pressurized Flow of a Hydropower System with a Flat Ceiling Tail Tunnel

by Jianxu Zhou and Yongfa Li

Water 2020, 12(3), 699; https://doi.org/10.3390/w12030699 - 4 Mar 2020

Cited by 5 | Viewed by 3479

Abstract

For a water diversion hydropower system with a flat ceiling tail tunnel with high elevation, during transient states with relatively low tail water levels, free-surface-pressurized flow inevitably appears and its transient characteristics have obvious effects on the system’s operating stability. Using Newton–Raphson linearization [...] Read more.

For a water diversion hydropower system with a flat ceiling tail tunnel with high elevation, during transient states with relatively low tail water levels, free-surface-pressurized flow inevitably appears and its transient characteristics have obvious effects on the system’s operating stability. Using Newton–Raphson linearization in the characteristic implicit format for modeling of the free-surface-pressurized flow in the tail tunnel, the mathematical models for necessary boundary conditions were derived and linear algebraic equations with a band coefficient matrix were grouped for further transient simulation. Then, a unified mathematical model was established for hydraulic transient analysis of the hydropower system with free-surface-pressurized flow. Combined with experimental research and numerical simulation, the wave speed for the free-surface-pressurized flow was experimentally analyzed for further correctness in the unified model, and by comparative analysis the hydraulic characteristics of the free-surface-pressurized flow in the flat ceiling tail tunnel were investigated. It was found that the derived mathematical model can basically represent water behaviors in the water-surface-pressurized flow, the wave speed for the mixed water-surface-pressurized flow can be set to approximately 50m/s, and with this correctness the numerical results are in good agreement with the experimental results. Therefore, the obtained mathematical model combined with an experimental wave speed or a reference wave speed of 50 m/s for the free-surface-pressurized flow is preferable during the design stage of the hydropower system. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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15 pages, 10030 KiB

Open AccessEditor’s ChoiceArticle

CFD–DEM Simulations of Seepage-Induced Erosion

by Qiong Xiao and Ji-Peng Wang

Water 2020, 12(3), 678; https://doi.org/10.3390/w12030678 - 2 Mar 2020

Cited by 19 | Viewed by 6882

Abstract

Increases in seepage force reduce the effective stress of particles and result in the erosion of particles, producing heave failure and piping. Sheet piles/cutoff walls are often employed in dams to control the seepage. In this study, a computational fluid dynamics solver involving [...] Read more.

Increases in seepage force reduce the effective stress of particles and result in the erosion of particles, producing heave failure and piping. Sheet piles/cutoff walls are often employed in dams to control the seepage. In this study, a computational fluid dynamics solver involving two fluid phases was developed and coupled with discrete element method software to simulate the piping process around a sheet pile/cutoff wall. Binary-sized particles were selected to study the impact of fine particles on the mechanisms of seepage. The seepage phenomenon mainly appeared among fine particles located in the downstream side, with the peak magnitudes of drag force and displacement occurring around the retaining wall. Based on the particle-scale observations, the impact of seepage produced a looser condition for the region concentrated around the retaining wall and resulted in an anisotropic condition in the soil skeleton. The results indicate that heave behavior occurs when the drag force located adjacent to the boundary on the downstream side is larger than the corresponding weight of the bulk soil. Full article

(This article belongs to the Special Issue Granular Flows Modeling and Simulation)

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30 pages, 6129 KiB

Open AccessEditor’s ChoiceArticle

GIS Based Hybrid Computational Approaches for Flash Flood Susceptibility Assessment

by Binh Thai Pham, Mohammadtaghi Avand, Saeid Janizadeh, Tran Van Phong, Nadhir Al-Ansari, Lanh Si Ho, Sumit Das, Hiep Van Le, Ata Amini, Saeid Khosrobeigi Bozchaloei, Faeze Jafari and Indra Prakash

Water 2020, 12(3), 683; https://doi.org/10.3390/w12030683 - 2 Mar 2020

Cited by 177 | Viewed by 10151

Abstract

Flash floods are one of the most devastating natural hazards; they occur within a catchment (region) where the response time of the drainage basin is short. Identification of probable flash flood locations and development of accurate flash flood susceptibility maps are important for [...] Read more.

Flash floods are one of the most devastating natural hazards; they occur within a catchment (region) where the response time of the drainage basin is short. Identification of probable flash flood locations and development of accurate flash flood susceptibility maps are important for proper flash flood management of a region. With this objective, we proposed and compared several novel hybrid computational approaches of machine learning methods for flash flood susceptibility mapping, namely AdaBoostM1 based Credal Decision Tree (ABM-CDT); Bagging based Credal Decision Tree (Bag-CDT); Dagging based Credal Decision Tree (Dag-CDT); MultiBoostAB based Credal Decision Tree (MBAB-CDT), and single Credal Decision Tree (CDT). These models were applied at a catchment of Markazi state in Iran. About 320 past flash flood events and nine flash flood influencing factors, namely distance from rivers, aspect, elevation, slope, rainfall, distance from faults, soil, land use, and lithology were considered and analyzed for the development of flash flood susceptibility maps. Correlation based feature selection method was used to validate and select the important factors for modeling of flash floods. Based on this feature selection analysis, only eight factors (distance from rivers, aspect, elevation, slope, rainfall, soil, land use, and lithology) were selected for the modeling, where distance to rivers is the most important factor for modeling of flash flood in this area. Performance of the models was validated and compared by using several robust metrics such as statistical measures and Area Under the Receiver Operating Characteristic (AUC) curve. The results of this study suggested that ABM-CDT (AUC = 0.957) has the best predictive capability in terms of accuracy, followed by Dag-CDT (AUC = 0.947), MBAB-CDT (AUC = 0.933), Bag-CDT (AUC = 0.932), and CDT (0.900), respectively. The proposed methods presented in this study would help in the development of accurate flash flood susceptible maps of watershed areas not only in Iran but also other parts of the world. Full article

(This article belongs to the Special Issue Modelling of Floods in Urban Areas)

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19 pages, 1019 KiB

Open AccessEditor’s ChoiceArticle

Nexus between Ecological Conservation and Socio-Economic Development and its Dynamics: Insights from a Case in China

by Jian Wu, Yanan Guo and Jingbo Zhou

Water 2020, 12(3), 663; https://doi.org/10.3390/w12030663 - 1 Mar 2020

Cited by 12 | Viewed by 5172

Abstract

Achieving sustainable socio-economic development in areas designated for ecological conservation is a challenge for many developing countries. The nexus between ecological conservation and socio-economic development is particularly complex in these areas for the reason that most of them are located in poor regions [...] Read more.

Achieving sustainable socio-economic development in areas designated for ecological conservation is a challenge for many developing countries. The nexus between ecological conservation and socio-economic development is particularly complex in these areas for the reason that most of them are located in poor regions and their resource utilization is constrained by ecological conservation practices. A conceptual framework was proposed for examining the nexus between ecological conservation and economic development in a social-ecological system to explain the pathways and mechanisms of influence between the ecosystem and the social system. We chose the Lashihai watershed in Yunnan Province, China, as the case study area to explore whether a positive feedback loop between ecological conservation and socio-economic development has been formed, as well as how to promote the positive evolution of socio-economic and ecological status. The ecosystem and socio-economic system in the Lashihai watershed closely interact and form a dynamic system with a positive evolutionary trend. If negative factors, such as an uneven distribution of income and new population pressures, are not appropriately managed, they are likely to break the positive feedback loop and trap the system in a negative feedback loop. We discuss the main factors that contribute to the interactions between ecological conservation and livelihoods, and develop policy recommendations for governments in other countries and regions to promote conservation and better livelihoods in conjunction. Full article

(This article belongs to the Special Issue Water Management Challenges in an Increasingly Warm and Crowded Planet)

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21 pages, 3579 KiB

Open AccessEditor’s ChoiceArticle

Biodiversity of Calanoida Copepoda in Different Habitats of the North-Western Red Sea (Hurghada Shelf)

by Hamdy Abo-Taleb, Mohamed Ashour, Ahmed El-Shafei, Abed Alataway and Mahmoud M. Maaty

Water 2020, 12(3), 656; https://doi.org/10.3390/w12030656 - 29 Feb 2020

Cited by 42 | Viewed by 6081

Abstract

Little is known about the diversity of Calanoida, Copepoda, in different habitats of the north-western Red Sea. In this study, biodiversity of Calanoida, Copepoda, during the cold and warm seasons of 2017, were observed at 12 stations belonging to four different habitats (coral [...] Read more.

Little is known about the diversity of Calanoida, Copepoda, in different habitats of the north-western Red Sea. In this study, biodiversity of Calanoida, Copepoda, during the cold and warm seasons of 2017, were observed at 12 stations belonging to four different habitats (coral reef (CR), sheltered shallow lagoons (SSL), seagrass (SG), and open deep-water (ODW) habitats) in the Hurghada shelf, north-western Red Sea. SSL habitats were the most affected by environmental conditions, especially temperature, salinity, and depth. Some calanoid species were restricted to certain habitats, others were adapted to live in more than one habitat, while some species showed a wide distribution in all habitats. ODW habitats showed maximum diversity and density of the calanoid species. The effects of temperature and salinity were distinct in the SG and SSL. The results clearly showed that different Red Sea habitats affected the biodiversity of calanoid copepods. Full article

(This article belongs to the Special Issue Marine Biology: Biodiversity and Conservation)

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29 pages, 9095 KiB

Open AccessEditor’s ChoiceArticle

Hydrodynamic Modeling and Simulation of Water Residence Time in the Estuary of the Lower Amazon River

by Carlos Henrique M. de Abreu, Maria de Lourdes Cavalcanti Barros, Daímio Chaves Brito, Marcelo Rassy Teixeira and Alan Cavalcanti da Cunha

Water 2020, 12(3), 660; https://doi.org/10.3390/w12030660 - 29 Feb 2020

Cited by 28 | Viewed by 6661

Abstract

Studies about the hydrodynamic behavior in the lower Amazon River remain scarce, despite their relevance and complexity, and the Water Residence Time (Rt) of this Amazonian estuary remains poorly unknown. Therefore, the present study aims to numerically simulate three seasonal Rt scenarios based [...] Read more.

Studies about the hydrodynamic behavior in the lower Amazon River remain scarce, despite their relevance and complexity, and the Water Residence Time (Rt) of this Amazonian estuary remains poorly unknown. Therefore, the present study aims to numerically simulate three seasonal Rt scenarios based on a calibrated hydrodynamic numerical model (SisbaHiA) applied to a representative stretch of the lower Amazon River. The following methodological steps were performed: (a) establishing experimental water flow in natural channels; (b) statistically test numerical predictions (tidal range cycles for different hydrologic periods); and (c) simulating velocity fields and water discharge associated with Rt numerical outputs of the hydrodynamic model varied from 14 ≤ Rt ≤ 22 days among different seasonal periods. This change has shown the significant influence of hydrologic period and geomorphological features on Rt. Rt, in its turn, has shown significant spatial heterogeneity, depending on location and stretch of the channels. Comparative analyses between simulated and experimental parameters evidenced statistical correlations higher than 0.9. We conclude that the generated Rt scenarios were consistent with other similar studies in the literature. Therefore, they depicted the applicability of the hydrodynamics to the conservation of the Amazonian aquatic ecosystem, as well as its relevance for biochemical and pollutant dispersion studies, which still remain scarce in the literature. Full article

(This article belongs to the Section Urban Water Management)

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31 pages, 9108 KiB

Open AccessEditor’s ChoiceArticle

Emptying Water Towers? Impacts of Future Climate and Glacier Change on River Discharge in the Northern Tien Shan, Central Asia

by Maria Shahgedanova, Muhammad Afzal, Wilfried Hagg, Vassiliy Kapitsa, Nikolay Kasatkin, Elizabeth Mayr, Oleg Rybak, Zarina Saidaliyeva, Igor Severskiy, Zamira Usmanova, Andrew Wade, Natalia Yaitskaya and Dauren Zhumabayev

Water 2020, 12(3), 627; https://doi.org/10.3390/w12030627 - 26 Feb 2020

Cited by 36 | Viewed by 6565

Abstract

Impacts of projected climate and glacier change on river discharge in five glacierized catchments in the northern Tien Shan, Kazakhstan are investigated using a conceptual hydrological model HBV-ETH. Regional climate model PRECIS driven by four different GCM-scenario combinations (HadGEM2.6, HadGEM8.5, A1B using HadCM3Q0 [...] Read more.

Impacts of projected climate and glacier change on river discharge in five glacierized catchments in the northern Tien Shan, Kazakhstan are investigated using a conceptual hydrological model HBV-ETH. Regional climate model PRECIS driven by four different GCM-scenario combinations (HadGEM2.6, HadGEM8.5, A1B using HadCM3Q0 and ECHAM5) is used to develop climate projections. Future changes in glaciation are assessed using the Blatter–Pattyn type higher-order 3D coupled ice flow and mass balance model. All climate scenarios show statistically significant warming in the 21st Century. Neither projects statistically significant change in annual precipitation although HadGEM and HadCM3Q0-driven scenarios show 20–37% reduction in July–August precipitation in 2076–2095 in comparison with 1980–2005. Glaciers are projected to retreat rapidly until the 2050s and stabilize afterwards except under the HadGEM8.5 scenario where retreat continues. Glaciers are projected to lose 38–50% of their volume and 34–39% of their area. Total river discharge in July–August, is projected to decline in catchments with low (2–4%) glacierization by 20–37%. In catchments with high glacierization (16% and over), no significant changes in summer discharge are expected while spring discharge is projected to increase. In catchments with medium glacierization (10–12%), summer discharge is expected to decline under the less aggressive scenarios while flow is sustained under the most aggressive HadGEM8.5 scenario, which generates stronger melt. Full article

(This article belongs to the Special Issue Impacts of Climate Change on Water Resources in Glacierized Regions)

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17 pages, 1607 KiB

Open AccessEditor’s ChoiceReview

Influences of Land-Use Dynamics and Surface Water Systems Interactions on Water-Related Infectious Diseases—A Systematic Review

by Joshua Ntajal, Timo Falkenberg, Thomas Kistemann and Mariele Evers

Water 2020, 12(3), 631; https://doi.org/10.3390/w12030631 - 26 Feb 2020

Cited by 9 | Viewed by 6310

Abstract

Human interactions with surface water systems, through land-use dynamics, can influence the transmission of infectious water-related diseases. As a result, the aim of our study was to explore and examine the state of scientific evidence on the influences of these interactions on water-related [...] Read more.

Human interactions with surface water systems, through land-use dynamics, can influence the transmission of infectious water-related diseases. As a result, the aim of our study was to explore and examine the state of scientific evidence on the influences of these interactions on water-related infectious disease outcomes from a global perspective. A systematic review was conducted, using 54 peer-reviewed research articles published between 1995 and August 2019. The study revealed that there has been an increase in the number of publications since 2009; however, few of these publications (n = 6) made explicit linkages to the topic. It was found that urban and agricultural land-use changes had relatively high adverse impacts on water quality, due to high concentrations of fecal matter, heavy metals, and nutrients in surface water systems. Water systems were found as the common “vehicle” for infectious disease transmission, which in turn had linkages to sanitation and hygiene conditions. The study found explicit linkages between human–surface water interaction patterns and the transmission of water-based disease. However, weak and complex linkages were found between land-use change and the transmission of water-borne disease, due to multiple pathways and the dynamics of the other determinants of the disease. Therefore, further research studies, using interdisciplinary and transdisciplinary approaches to investigate and enhance a deeper understanding of these complexities and linkages among land use, surface water quality, and water-related infectious diseases, is crucial in developing integrated measures for sustainable water quality monitoring and diseases prevention. Full article

(This article belongs to the Section Water Quality and Contamination)

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15 pages, 1433 KiB

Open AccessEditor’s ChoiceArticle

Water Allocation Using the Bankruptcy Model: A Case Study of the Missouri River

by Heshani Manaweera Wickramage, David C. Roberts and Robert R. Hearne

Water 2020, 12(3), 619; https://doi.org/10.3390/w12030619 - 25 Feb 2020

Cited by 10 | Viewed by 4371

Abstract

This research applies cooperative game theory—specifically, the bankruptcy model—to address conflicts arising from the scarcity of water resources shared by multiple agents. This case study addresses potential outcomes of five allocation rules applied to the apportionment of water between two agents in the [...] Read more.

This research applies cooperative game theory—specifically, the bankruptcy model—to address conflicts arising from the scarcity of water resources shared by multiple agents. This case study addresses potential outcomes of five allocation rules applied to the apportionment of water between two agents in the Missouri River. Currently, there is no interstate compact to apportion Missouri River and frequent disputes between upstream and downstream states occur. Upstream states favor managing reservoir water levels to support reservoir recreation and downstream states want water for the downstream navigation channel. The five allocation rules studied are (1) Proportional Sharing, (2) Constrained Equal Awards, (3) Constrained Equal Losses, (4) Sequential Sharing based on Proportional Sharing, and (5) a proposed Modified Constrained Equal Awards rule. The results of the analysis of apportionment during four dry years in the 2000s show that the best approaches are the proposed Modified Constrained Equal Awards Rule and the Proportional Sharing Rule. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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17 pages, 4792 KiB

Open AccessEditor’s ChoiceArticle

Towards an Assessment of the Ephemeral Gully Erosion Potential in Greece Using Google Earth

by Christos Karydas and Panos Panagos

Water 2020, 12(2), 603; https://doi.org/10.3390/w12020603 - 23 Feb 2020

Cited by 38 | Viewed by 6249

Abstract

Gully erosion may cause considerable soil losses and produce large volumes of sediment. The aim of this study was to perform a preliminary assessment on the presence of ephemeral gullies in Greece by sampling representative cultivated fields in 100 sites randomly distributed throughout [...] Read more.

Gully erosion may cause considerable soil losses and produce large volumes of sediment. The aim of this study was to perform a preliminary assessment on the presence of ephemeral gullies in Greece by sampling representative cultivated fields in 100 sites randomly distributed throughout the country. The almost 30-ha sampling surfaces were examined with visual interpretation of multi-temporal imagery from the online Google Earth for the period 2002–2019. In parallel, rill and sheet erosion signs, land uses, and presence of terraces and other anti-erosion features, were recorded within every sample. One hundred fifty-three ephemeral gullies were identified in total, inside 22 examined agricultural surfaces. The mean length of the gullies was 55.6 m, with an average slope degree of 9.7%. Vineyards showed the largest proportion of gullies followed by olive groves and arable land, while pastures exhibited limited presence of gullies. Spatial clusters of high gully severity were observed in the north and east of the country. In 77% of the surfaces with gullies, there were no terraces, although most of these surfaces were situated in slopes higher than 8%. It was the first time to use visual interpretation with Google Earth image time-series on a country scale producing a gully erosion inventory. Soil conservation practices such as contour farming and terraces could mitigate the risk of gully erosion in agricultural areas. Full article

(This article belongs to the Special Issue The Effect of Hydrology on Soil Erosion)

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19 pages, 6050 KiB

Open AccessEditor’s ChoiceArticle

Transient-Flow Induced Compressed Air Energy Storage (TI-CAES) System towards New Energy Concept

by Mohsen Besharat, Avin Dadfar, Maria Teresa Viseu, Bruno Brunone and Helena M. Ramos

Water 2020, 12(2), 601; https://doi.org/10.3390/w12020601 - 22 Feb 2020

Cited by 10 | Viewed by 5882

Abstract

In recent years, interest has increased in new renewable energy solutions for climate change mitigation and increasing the efficiency and sustainability of water systems. Hydropower still has the biggest share due to its compatibility, reliability and flexibility. This study presents one such technology [...] Read more.

In recent years, interest has increased in new renewable energy solutions for climate change mitigation and increasing the efficiency and sustainability of water systems. Hydropower still has the biggest share due to its compatibility, reliability and flexibility. This study presents one such technology recently examined at Instituto Superior Técnico based on a transient-flow induced compressed air energy storage (TI-CAES) system, which takes advantage of a compressed air vessel (CAV). The CAV can produce extra required pressure head, by compressing air, to be used for either hydropower generation using a water turbine in a gravity system or to be exploited in a pumping system. The results show a controlled behaviour of the system in storing the pressure surge as compressed air inside a vessel. Considerable power values are achieved as well, while the input work is practically neglected. Higher power values are attained for bigger air volumes. The TI-CAES offers an efficient and flexible solution that can be exploited in exiting water systems without putting the system at risk. The induced transients in the compressed air allow a constant outflow discharge characteristic, making the energy storage available in the CAV to be used as a pump storage hydropower solution. Full article

(This article belongs to the Special Issue Environmental Hydraulics Research)

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19 pages, 3701 KiB

Open AccessEditor’s ChoiceArticle

Adsorption of Methylene Blue in Water onto Activated Carbon by Surfactant Modification

by Yu Kuang, Xiaoping Zhang and Shaoqi Zhou

Water 2020, 12(2), 587; https://doi.org/10.3390/w12020587 - 21 Feb 2020

Cited by 459 | Viewed by 25257

Abstract

In this paper, the enhanced adsorption of methylene blue (MB) dye ion on the activated carbon (AC) modified by three surfactants in aqueous solution was researched. Anionic surfactants—sodium lauryl sulfate (SLS) and sodium dodecyl sulfonate (SDS)—and cationic surfactant—hexadecyl trimethyl ammonium bromide (CTAB)—were used [...] Read more.

In this paper, the enhanced adsorption of methylene blue (MB) dye ion on the activated carbon (AC) modified by three surfactants in aqueous solution was researched. Anionic surfactants—sodium lauryl sulfate (SLS) and sodium dodecyl sulfonate (SDS)—and cationic surfactant—hexadecyl trimethyl ammonium bromide (CTAB)—were used for the modification of AC. This work showed that the adsorption performance of cationic dye by activated carbon modified by anionic surfactants (SLS) was significantly improved, whereas the adsorption performance of cationic dye by activated carbon modified by cationic surfactant (CTAB) was reduced. In addition, the effects of initial MB concentration, AC dosage, pH, reaction time, temperature, real water samples, and additive salts on the adsorption were studied. When Na⁺, K⁺, Ca²⁺, NH⁴⁺, and Mg²⁺ were present in the MB dye solution, the effect of these cations was negligible on the adsorption (<5%). The presence of NO^2- improved the adsorption performance significantly, whereas the removal rate of MB was reduced in the presence of competitive cation (Fe²⁺). It was found that the isotherm data had a good correlation with the Langmuir isotherm through analyzing the experimental data by various models. The dynamics of adsorption were better described by the pseudo-second-order model and the adsorption process was endothermic and spontaneous. The results showed that AC modified by anionic surfactant was effective for the adsorption of MB dye in both modeling water and real water. Full article

(This article belongs to the Special Issue Adsorbents for Water and Wastewater Treatment and Resource Recovery)

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13 pages, 455 KiB

Open AccessEditor’s ChoiceArticle

Flipped Learning Approach as Educational Innovation in Water Literacy

by Antonio-José Moreno-Guerrero, José-María Romero-Rodríguez, Jesús López-Belmonte and Santiago Alonso-García

Water 2020, 12(2), 574; https://doi.org/10.3390/w12020574 - 20 Feb 2020

Cited by 47 | Viewed by 7769

Abstract

Water literacy has become a fundamental aspect in today’s society, as its conservation, preservation and management is key to ensuring human survival. The purpose of this paper was to analyze the effectiveness of flipped learning methodology on a traditional training practice in water [...] Read more.

Water literacy has become a fundamental aspect in today’s society, as its conservation, preservation and management is key to ensuring human survival. The purpose of this paper was to analyze the effectiveness of flipped learning methodology on a traditional training practice in water literacy at the first level of secondary education. The flipped learning method consisted in providing the contents to the students before the class sessions, encouraging an active learning. A descriptive study was adopted with two experimental groups, two control groups and only post-test. An ad hoc questionnaire was used as an instrument to measure the parameters: Socio-educational, Motivation, Interactions, Autonomy, Collaboration; Deepening of contents; Problem solving, Class time and Ratings. The final sample was composed of 120 students, divided into four groups of 30 students each. The application of the treatment in the experimental groups lasted 10 sessions of 55 min. The results indicate that the use of time in class, the autonomy and the deepening of the contents were the aspects that improved most with the flipped learning approach. However, no significant differences in ratings were found. Finally, the main findings and their implications for water literacy are discussed. Full article

(This article belongs to the Special Issue Water Literacy and Education)

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15 pages, 2225 KiB

Open AccessEditor’s ChoiceArticle

Improving the Reliability of Probabilistic Multi-Step-Ahead Flood Forecasting by Fusing Unscented Kalman Filter with Recurrent Neural Network

by Yanlai Zhou, Shenglian Guo, Chong-Yu Xu, Fi-John Chang and Jiabo Yin

Water 2020, 12(2), 578; https://doi.org/10.3390/w12020578 - 20 Feb 2020

Cited by 43 | Viewed by 5726

Abstract

It is fundamentally challenging to quantify the uncertainty of data-driven flood forecasting. This study introduces a general framework for probabilistic flood forecasting conditional on point forecasts. We adopt an unscented Kalman filter (UKF) post-processing technique to model the point forecasts made by a [...] Read more.

It is fundamentally challenging to quantify the uncertainty of data-driven flood forecasting. This study introduces a general framework for probabilistic flood forecasting conditional on point forecasts. We adopt an unscented Kalman filter (UKF) post-processing technique to model the point forecasts made by a recurrent neural network and their corresponding observations. The methodology is tested by using a long-term 6-h timescale inflow series of the Three Gorges Reservoir in China. The main merits of the proposed approach lie in: first, overcoming the under-prediction phenomena in data-driven flood forecasting; second, alleviating the uncertainty encountered in data-driven flood forecasting. Two commonly used artificial neural networks, a recurrent and a static neural network, were used to make the point forecasts. Then the UKF approach driven by the point forecasts demonstrated its competency in increasing the reliability of probabilistic flood forecasts significantly, where predictive distributions encountered in multi-step-ahead flood forecasts were effectively reduced to small ranges. The results demonstrated that the UKF plus recurrent neural network approach could suitably extract the complex non-linear dependence structure between the model’s outputs and observed inflows and overcome the systematic error so that model reliability as well as forecast accuracy for future horizons could be significantly improved. Full article

(This article belongs to the Special Issue Advances in Hydrologic Forecasts and Water Resources Management )

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15 pages, 1793 KiB

Open AccessEditor’s ChoiceArticle

Predicting the Trend of Dissolved Oxygen Based on the kPCA-RNN Model

by Yi-Fan Zhang, Peter Fitch and Peter J. Thorburn

Water 2020, 12(2), 585; https://doi.org/10.3390/w12020585 - 20 Feb 2020

Cited by 79 | Viewed by 5892

Abstract

Water quality forecasting is increasingly significant for agricultural management and environmental protection. Enormous amounts of water quality data are collected by advanced sensors, which leads to an interest in using data-driven models for predicting trends in water quality. However, the unpredictable background noises [...] Read more.

Water quality forecasting is increasingly significant for agricultural management and environmental protection. Enormous amounts of water quality data are collected by advanced sensors, which leads to an interest in using data-driven models for predicting trends in water quality. However, the unpredictable background noises introduced during water quality monitoring seriously degrade the performance of those models. Meanwhile, artificial neural networks (ANN) with feed-forward architecture lack the capability of maintaining and utilizing the accumulated temporal information, which leads to biased predictions in processing time series data. Hence, we propose a water quality predictive model based on a combination of Kernal Principal Component Analysis (kPCA) and Recurrent Neural Network (RNN) to forecast the trend of dissolved oxygen. Water quality variables are reconstructed based on the kPCA method, which aims to reduce the noise from the raw sensory data and preserve actionable information. With the RNN’s recurrent connections, our model can make use of the previous information in predicting the trend in the future. Data collected from Burnett River, Australia was applied to evaluate our kPCA-RNN model. The kPCA-RNN model achieved

R^{2}

scores up to 0.908, 0.823, and 0.671 for predicting the concentration of dissolved oxygen in the upcoming 1, 2 and 3 hours, respectively. Compared to current data-driven methods like Feed-forward neural network (FFNN), support vector regression (SVR) and general regression neural network (GRNN), the predictive accuracy of the kPCA-RNN model was at least 8%, 17% and 12% better than the comparative models in these three cases. The study demonstrates the effectiveness of the kPAC-RNN modeling technique in predicting water quality variables with noisy sensory data. Full article

(This article belongs to the Special Issue Land Use and Water Quality)

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15 pages, 8454 KiB

Open AccessEditor’s ChoiceArticle

The Susceptibility of Juvenile American Shad to Rapid Decompression and Fluid Shear Exposure Associated with Simulated Hydroturbine Passage

by Brett D. Pflugrath, Ryan A. Harnish, Briana Rhode, Kristin Engbrecht, Bernardo Beirão, Robert P. Mueller, Erin L. McCann, John R. Stephenson and Alison H. Colotelo

Water 2020, 12(2), 586; https://doi.org/10.3390/w12020586 - 20 Feb 2020

Cited by 9 | Viewed by 3957

Abstract

Throughout many areas of their native range, American shad (Alosa sapidissima) and other Alosine populations are in decline. Though several conditions have influenced these declines, hydropower facilities have had significant negative effects on American shad populations. Hydropower facilities expose ocean-migrating American [...] Read more.

Throughout many areas of their native range, American shad (Alosa sapidissima) and other Alosine populations are in decline. Though several conditions have influenced these declines, hydropower facilities have had significant negative effects on American shad populations. Hydropower facilities expose ocean-migrating American shad to physical stressors during passage through hydropower facilities, including strike, rapid decompression, and fluid shear. In this laboratory-based study, juvenile American shad were exposed separately to rapid decompression and fluid shear to determine their susceptibility to these stressors and develop dose–response models. These dose–response relationships can help guide the development and/or operation of hydropower turbines and facilities to reduce the negative effects to American shad. Relative to other species, juvenile American shad have a high susceptibility to both rapid decompression and fluid shear. Reducing or preventing exposure to these stressors at hydropower facilities may be a potential method to assist in the effort to restore American shad populations. Full article

(This article belongs to the Special Issue Addressing the Environmental Impacts of Hydropower)

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29 pages, 1851 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Recent Advances in Real-Time Pluvial Flash Flood Forecasting

by Andre D. L. Zanchetta and Paulin Coulibaly

Water 2020, 12(2), 570; https://doi.org/10.3390/w12020570 - 19 Feb 2020

Cited by 75 | Viewed by 11678

Abstract

Recent years have witnessed considerable developments in multiple fields with the potential to enhance our capability of forecasting pluvial flash floods, one of the most costly environmental hazards in terms of both property damage and loss of life. This work provides a summary [...] Read more.

Recent years have witnessed considerable developments in multiple fields with the potential to enhance our capability of forecasting pluvial flash floods, one of the most costly environmental hazards in terms of both property damage and loss of life. This work provides a summary and description of recent advances related to insights on atmospheric conditions that precede extreme rainfall events, to the development of monitoring systems of relevant hydrometeorological parameters, and to the operational adoption of weather and hydrological models towards the prediction of flash floods. With the exponential increase of available data and computational power, most of the efforts are being directed towards the improvement of multi-source data blending and assimilation techniques, as well as assembling approaches for uncertainty estimation. For urban environments, in which the need for high-resolution simulations demands computationally expensive systems, query-based approaches have been explored for the timely retrieval of pre-simulated flood inundation forecasts. Within the concept of the Internet of Things, the extensive deployment of low-cost sensors opens opportunities from the perspective of denser monitoring capabilities. However, different environmental conditions and uneven distribution of data and resources usually leads to the adoption of site-specific solutions for flash flood forecasting in the context of early warning systems. Full article

(This article belongs to the Special Issue Advances in Flash Flood Forecasting)

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14 pages, 4739 KiB

Open AccessEditor’s ChoiceArticle

When Green Infrastructure Turns Grey: Plant Water Stress as a Consequence of Overdesign in a Tree Trench System

by Min-cheng Tu, Joshua S. Caplan, Sasha W. Eisenman and Bridget M. Wadzuk

Water 2020, 12(2), 573; https://doi.org/10.3390/w12020573 - 19 Feb 2020

Cited by 19 | Viewed by 4201

Abstract

Green infrastructure (GI) systems are often overdesigned. This may be a byproduct of static sizing (e.g., accounting for a design storm’s runoff volume but not exfiltration rates) or may be deliberate (e.g., buffering against performance loss through time). In tree trenches and other [...] Read more.

Green infrastructure (GI) systems are often overdesigned. This may be a byproduct of static sizing (e.g., accounting for a design storm’s runoff volume but not exfiltration rates) or may be deliberate (e.g., buffering against performance loss through time). In tree trenches and other GI systems that require stormwater to accumulate in an infiltration bed before it contacts the planting medium, overdesign could reduce plant water availability significantly. This study investigated the hydrological dynamics and water relations of an overdesigned tree trench system and identified factors contributing to, compounding, and mitigating the risk of plant stress. Water in the infiltration bed reached soil pits only once in three years, with that event occurring during a hydrant release. Moreover, minimal water was retained in soil pits during the event due to the hydraulic properties of the soil media. Through a growing season, one of the two tree types frequently experienced water stress, while the other did so only rarely. These contrasting responses can likely be attributed to roots being largely confined to the soil pits vs. reaching a deeper water source, respectively. Results of this study demonstrate that, in systems where soil pits are embedded in infiltration beds, overdesign can raise the storm size required for water to reach the soil media, reducing plant water availability between storms, and ultimately inducing physiological stress. Full article

(This article belongs to the Special Issue Advances of Low Impact Development Practices in Urban Watershed)

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26 pages, 4994 KiB

Open AccessEditor’s ChoiceArticle

Hydrogeochemical Characteristics and Assessment of Drinking Water Quality in the Urban Area of Zamora, Mexico

by Claudia Alejandra Reyes-Toscano, Ruth Alfaro-Cuevas-Villanueva, Raúl Cortés-Martínez, Ofelia Morton-Bermea, Elizabeth Hernández-Álvarez, Otoniel Buenrostro-Delgado and Jorge Alejandro Ávila-Olivera

Water 2020, 12(2), 556; https://doi.org/10.3390/w12020556 - 17 Feb 2020

Cited by 58 | Viewed by 6312

Abstract

This work assessed the groundwater hydrogeochemistry and the drinking water quality of 10 wells supplying the urban area of Zamora, Michoacán, Mexico. Two sampling campaigns were conducted in May 2018 (dry season) and November 2018 (wet season) to describe the chemistry of the [...] Read more.

This work assessed the groundwater hydrogeochemistry and the drinking water quality of 10 wells supplying the urban area of Zamora, Michoacán, Mexico. Two sampling campaigns were conducted in May 2018 (dry season) and November 2018 (wet season) to describe the chemistry of the water and its interaction with the rock. Physical and chemical constituents (temperature, pH, electrical conductivity, color, turbidity, solids, total hardness, total alkalinity, chemical and biochemical oxygen demands), major components (Ca²⁺, Mg²⁺, Na⁺, K⁺, SO₄²⁻, PO₄³⁻, HCO₃⁻, CO₃²⁻, Cl⁻, N-NO₃⁻, and N-NH₃), as well as trace elements (As, Fe, Mn, Ba, Al, Sb, Co, V, Cu, Cd, Cr, Ni, Zn, Tl, Pb) were analyzed. Results showed groundwater with a slight tendency to alkalinity. The hydrogeochemical facies observed are Ca²⁺-HCO₃⁻ in all sites. Hydrochemical diagrams indicate immature, cold, non-saline, and uncontaminated water with short residence time. Water–rock interaction predominates. The water in the study area is appropriate for drinking use according to Mexican and international regulations with an excellent quality in 7 wells and good in the other 3. Full article

(This article belongs to the Section Water Quality and Contamination)

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25 pages, 6912 KiB

Open AccessEditor’s ChoiceArticle

Social Vulnerability Assessment for Flood Risk Analysis

by Laura Tascón-González, Montserrat Ferrer-Julià, Maurici Ruiz and Eduardo García-Meléndez

Water 2020, 12(2), 558; https://doi.org/10.3390/w12020558 - 17 Feb 2020

Cited by 82 | Viewed by 13146

Abstract

This paper proposes a methodology for the analysis of social vulnerability to floods based on the integration and weighting of a range of exposure and resistance (coping capacity) indicators. It focuses on the selection and characteristics of each proposed indicator and the integration [...] Read more.

This paper proposes a methodology for the analysis of social vulnerability to floods based on the integration and weighting of a range of exposure and resistance (coping capacity) indicators. It focuses on the selection and characteristics of each proposed indicator and the integration procedure based on the analytic hierarchy process (AHP) on a large scale. The majority of data used for the calculation of the indicators comes from open public data sources, which allows the replicability of the method in any area where the same data are available. To demonstrate the feasibility of the method, a study case is presented. The flood social vulnerability assessment focuses on the municipality of Ponferrada (Spain), a medium-sized town that has high exposure to floods due to potential breakage of the dam located upstream. A detailed mapping of the social vulnerability index is generated at the urban parcel scale, which shows an affected population of 34,941 inhabitants. The capability of working with such detailed units of analysis for an entire medium-sized town provides a valuable tool to support flood risk planning and management. Full article

(This article belongs to the Special Issue Flood Risk Assessments: Applications and Uncertainties)

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16 pages, 4746 KiB

Open AccessEditor’s ChoiceArticle

An Integral 1-D Eulerian–Lagrangian Method and Its Application to a Hydrodynamic River Network

by Shuai Yuan, Jianzhong Zhou, Dechao Hu and Sipeng Zhu

Water 2020, 12(2), 542; https://doi.org/10.3390/w12020542 - 15 Feb 2020

Cited by 2 | Viewed by 2702

Abstract

It is difficult for a one-dimensional river network hydrodynamic model to manage bifurcations. Traditional methods use simplified junction methods to avoid solving physical equations at bifurcations, which can cause physical distortions and errors. In this article, we propose an algorithm that allows a [...] Read more.

It is difficult for a one-dimensional river network hydrodynamic model to manage bifurcations. Traditional methods use simplified junction methods to avoid solving physical equations at bifurcations, which can cause physical distortions and errors. In this article, we propose an algorithm that allows a Eulerian–Lagrangian method (ELM) to track through bifurcations then solve advective terms, in combination with velocity–pressure couplings, to solve physical equations at bifurcations. The new method discards the simplifications and assumptions used by traditional models and is more complete in theory. We tested the new method with two ideal examples, and the results showed that the new method is time-step independent and grid independent. A simple bifurcation was used to compare this method with MIKE11. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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17 pages, 3186 KiB

Open AccessEditor’s ChoiceArticle

Source and Mobilization Mechanism of Iron, Manganese and Arsenic in Groundwater of Shuangliao City, Northeast China

by Zhihao Zhang, Changlai Xiao, Oluwafemi Adeyeye, Weifei Yang and Xiujuan Liang

Water 2020, 12(2), 534; https://doi.org/10.3390/w12020534 - 14 Feb 2020

Cited by 104 | Viewed by 7118

Abstract

Excessive levels of Fe, Mn and As are the main factors affecting groundwater quality in Songliao plain, northeast China. However, there are few studies on the source and mobilization mechanisms of Fe, Mn and As in the groundwater of Northeastern China. This study [...] Read more.

Excessive levels of Fe, Mn and As are the main factors affecting groundwater quality in Songliao plain, northeast China. However, there are few studies on the source and mobilization mechanisms of Fe, Mn and As in the groundwater of Northeastern China. This study takes Shuangliao city in the middle of Songliao plain as an example, where the source and mobilization mechanisms of iron, manganese and arsenic in groundwater in the study area were analyzed by statistical methods and spatial analysis. The results show that the source of Fe and Mn in the groundwater of the platform is the iron and manganese nodules in the clay layer, while, in the river valley plain, it originates from the soil and the whole aquifer. The TDS, fluctuation in groundwater levels and the residence time are the important factors affecting the content of Fe and Mn in groundwater. The dissolution of iron and manganese minerals causes arsenic adsorbed on them to be released into groundwater. This study provides a basis for the rational utilization of groundwater and protection of people’s health in areas with high iron, manganese and arsenic contents. Full article

(This article belongs to the Special Issue Geochemistry of Water and Sediment)

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23 pages, 6420 KiB

Open AccessEditor’s ChoiceArticle

Effect of Seasonality on the Quantiles Estimation of Maximum Floodwater Levels in a Reservoir and Maximum Outflows

by José Ángel Aranda and R. García-Bartual

Water 2020, 12(2), 519; https://doi.org/10.3390/w12020519 - 13 Feb 2020

Cited by 4 | Viewed by 2629

Abstract

Certain relevant variables for dam safety and downstream safety assessments are analyzed using a stochastic approach. In particular, a method to estimate quantiles of maximum outflow in a dam spillway and maximum water level reached in the reservoir during a flood event is [...] Read more.

Certain relevant variables for dam safety and downstream safety assessments are analyzed using a stochastic approach. In particular, a method to estimate quantiles of maximum outflow in a dam spillway and maximum water level reached in the reservoir during a flood event is presented. The hydrological system analyzed herein is a small mountain catchment in north Spain, whose main river is a tributary of Ebro river. The ancient Foradada dam is located in this catchment. This dam has no gates, so that flood routing operation results from simple consideration of fixed crest spillway hydraulics. In such case, both mentioned variables (maximum outflow and maximum reservoir water level) are basically derived variables that depend on flood hydrograph characteristics and the reservoir’s initial water level. A Monte Carlo approach is performed to generate very large samples of synthetic hydrographs and previous reservoir levels. The use of extreme value copulas allows the ensembles to preserve statistical properties of historical samples and the observed empirical correlations. Apart from the classical approach based on annual periods, the modelling strategy is also applied differentiating two subperiods or seasons (i.e., summer and winter). This allows to quantify the return period distortion introduced when seasonality is ignored in the statistical analysis of the two relevant variables selected for hydrological risk assessment. Results indicate significant deviations for return periods over 125 years. For the analyzed case study, ignoring seasonal statistics and trends, yields to maximum outflows underestimation of 18% for T = 500 years and 29% for T = 1000 years were obtained. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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22 pages, 1982 KiB

Open AccessEditor’s ChoiceArticle

Guidelines for the Use of Unmanned Aerial Systems in Flood Emergency Response

by Gloria Salmoral, Monica Rivas Casado, Manoranjan Muthusamy, David Butler, Prathyush P. Menon and Paul Leinster

Water 2020, 12(2), 521; https://doi.org/10.3390/w12020521 - 13 Feb 2020

Cited by 43 | Viewed by 9764

Abstract

There is increasing interest in using Unmanned Aircraft Systems (UAS) in flood risk management activities including in response to flood events. However, there is little evidence that they are used in a structured and strategic manner to best effect. An effective response to [...] Read more.

There is increasing interest in using Unmanned Aircraft Systems (UAS) in flood risk management activities including in response to flood events. However, there is little evidence that they are used in a structured and strategic manner to best effect. An effective response to flooding is essential if lives are to be saved and suffering alleviated. This study evaluates how UAS can be used in the preparation for and response to flood emergencies and develops guidelines for their deployment before, during and after a flood event. A comprehensive literature review and interviews, with people with practical experience of flood risk management, compared the current organizational and operational structures for flood emergency response in both England and India, and developed a deployment analysis matrix of existing UAS applications. An online survey was carried out in England to assess how the technology could be further developed to meet flood emergency response needs. The deployment analysis matrix has the potential to be translated into an Indian context and other countries. Those organizations responsible for overseeing flood risk management activities including the response to flooding events will have to keep abreast of the rapid technological advances in UAS if they are to be used to best effect. Full article

(This article belongs to the Special Issue Flood Risk and Resilience)

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33 pages, 2256 KiB

Open AccessFeature PaperEditor’s ChoiceReview

It Is Not Easy Being Green: Recognizing Unintended Consequences of Green Stormwater Infrastructure

by Vinicius J. Taguchi, Peter T. Weiss, John S. Gulliver, Mira R. Klein, Raymond M. Hozalski, Lawrence A. Baker, Jacques C. Finlay, Bonnie L. Keeler and John L. Nieber

Water 2020, 12(2), 522; https://doi.org/10.3390/w12020522 - 13 Feb 2020

Cited by 96 | Viewed by 21018

Abstract

Green infrastructure designed to address urban drainage and water quality issues is often deployed without full knowledge of potential unintended social, ecological, and human health consequences. Though understood in their respective fields of study, these diverse impacts are seldom discussed together in a [...] Read more.

Green infrastructure designed to address urban drainage and water quality issues is often deployed without full knowledge of potential unintended social, ecological, and human health consequences. Though understood in their respective fields of study, these diverse impacts are seldom discussed together in a format understood by a broader audience. This paper takes a first step in addressing that gap by exploring tradeoffs associated with green infrastructure practices that manage urban stormwater including urban trees, stormwater ponds, filtration, infiltration, rain gardens, and green roofs. Each green infrastructure practice type performs best under specific conditions and when targeting specific goals, but regular inspections, maintenance, and monitoring are necessary for any green stormwater infrastructure (GSI) practice to succeed. We review how each of the above practices is intended to function and how they could malfunction in order to improve how green stormwater infrastructure is designed, constructed, monitored, and maintained. Our proposed decision-making framework, using both biophysical (biological and physical) science and social science, could lead to GSI projects that are effective, cost efficient, and just. Full article

(This article belongs to the Special Issue Urban Water Policy and Planning Strategies for an Uncertain Water Future)

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23 pages, 8851 KiB

Open AccessEditor’s ChoiceArticle

Streamflow Variability in Colombian Pacific Basins and Their Teleconnections with Climate Indices

by Teresita Canchala, Wilmar Loaiza Cerón, Félix Francés, Yesid Carvajal-Escobar, Rita Valéria Andreoli, Mary Toshie Kayano, Wilfredo Alfonso-Morales, Eduardo Caicedo-Bravo and Rodrigo Augusto Ferreira de Souza

Water 2020, 12(2), 526; https://doi.org/10.3390/w12020526 - 13 Feb 2020

Cited by 27 | Viewed by 5432

Abstract

Oceanic-atmospheric phenomena of different time scales concurrently might affect the streamflow in several basins around the world. The Atrato River Basin (ARB) and Patía River Basin (PRB) of the Colombian Pacific region are examples of such basins. Nevertheless, the relations between the streamflows [...] Read more.

Oceanic-atmospheric phenomena of different time scales concurrently might affect the streamflow in several basins around the world. The Atrato River Basin (ARB) and Patía River Basin (PRB) of the Colombian Pacific region are examples of such basins. Nevertheless, the relations between the streamflows in the ARB and PRB and the oceanic-atmospheric factors have not been examined considering different temporal scales. Hence, this article studies the relations of the climate indices and the variability of the streamflows in the ARB and PRB at interannual and decadal timescales. To this, the streamflow variability modes were obtained from the principal component analysis (PCA); furthermore, their linear dependence with indices of the El Niño/Southern Oscillation (ENSO), precipitation (PRP), the Choco low-level jet (CJ), and other indices were quantified through (a) Pearson and Kendall’s tau correlations, and (b) wavelet transform. The PCA presented a single significant mode for each basin, with an explained variance of around 80%. The correlation analyses between the PC1s of the ARB and PRB, and the climate indices showed significant positive (negative) high correlations with PRP, CJ, and Southern Oscillation Index (SOI) (ENSO indices). The wavelet coherence analysis showed significant coherencies between ENSO and ARB: at interannual (2–7 years) and decadal scale (8–14), preferably with the sea surface temperature (SST) in the east and west Tropical Pacific Ocean (TPO). For PRB with the SST in the central and western regions of the TPO in the interannual (4–8 years) and decadal (8–14 years) scales, the decreases (increases) in streamflow precede the El Niño (La Niña) events. These results indicate multiscale relations between the basins’ streamflow and climate phenomena not documented in previous works, relevant to forecast the extreme flow events in the Colombian Pacific rivers and for planning and implementing strategies for the sustainable use of water resources in the basins studied. Full article

(This article belongs to the Special Issue Assessment of Spatial and Temporal Variability of Water Resources)

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16 pages, 4175 KiB

Open AccessEditor’s ChoiceArticle

Modeling of River Channel Shading as a Factor for Changes in Hydromorphological Conditions of Small Lowland Rivers

by Tomasz Kałuża, Mariusz Sojka, Rafał Wróżyński, Joanna Jaskuła, Stanisław Zaborowski and Mateusz Hämmerling

Water 2020, 12(2), 527; https://doi.org/10.3390/w12020527 - 13 Feb 2020

Cited by 14 | Viewed by 3862

Abstract

The ecological water quality in rivers and streams is influenced both by the morphological factors (within the watercourse channel and by the dynamic factors associated with flow), as well as biological factors (connected with the flora and fauna characteristic of its specific area). [...] Read more.

The ecological water quality in rivers and streams is influenced both by the morphological factors (within the watercourse channel and by the dynamic factors associated with flow), as well as biological factors (connected with the flora and fauna characteristic of its specific area). This paper presents an analysis of the effect of river channel shading by trees and shrubs on hydromorphological changes in a selected reach of the Wełna River, Poland. The analysis was conducted on two adjacent cross-sections (one in a reach lined with trees, the other in an open area with no tree or shrub vegetation). Data were collected during field surveys in the years 2014 and 2019. According to the Water Framework Directive, the Wełna River represents a watercourse with small and average-sized watershed areas, with sand being the dominant substrate of the river bottom. Flow volume, distributions of velocity in the sections, as well as substrate grain-size characteristics and river bottom morphology, were determined based on field measurements. In the study, the leaf area index (LAI) of vegetation was measured in the reach lined with trees, while the number and species composition of macrophytes were determined in the investigated river reaches. Moreover, a digital surface model (DSM) and Geoinformation Information System GIS tools were used to illustrate variability in shading within the tree-lined reach. The DSM model was based on Light Detection and Ranging (LIDAR) data. The results of this study enable us to establish the relationship between river shading by vegetation covering the bank zone, and changes in hydromorphological parameters of the river channel. Full article

(This article belongs to the Special Issue The Application of Hydraulic and Sediment Transport Models in Fluvial Geomorphology)

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30 pages, 1778 KiB

Open AccessEditor’s ChoiceReview

Role of Nanomaterials in the Treatment of Wastewater: A Review

by Asim Ali Yaqoob, Tabassum Parveen, Khalid Umar and Mohamad Nasir Mohamad Ibrahim

Water 2020, 12(2), 495; https://doi.org/10.3390/w12020495 - 12 Feb 2020

Cited by 581 | Viewed by 49942

Abstract

Water is an essential part of life and its availability is important for all living creatures. On the other side, the world is suffering from a major problem of drinking water. There are several gases, microorganisms and other toxins (chemicals and heavy metals) [...] Read more.

Water is an essential part of life and its availability is important for all living creatures. On the other side, the world is suffering from a major problem of drinking water. There are several gases, microorganisms and other toxins (chemicals and heavy metals) added into water during rain, flowing water, etc. which is responsible for water pollution. This review article describes various applications of nanomaterial in removing different types of impurities from polluted water. There are various kinds of nanomaterials, which carried huge potential to treat polluted water (containing metal toxin substance, different organic and inorganic impurities) very effectively due to their unique properties like greater surface area, able to work at low concentration, etc. The nanostructured catalytic membranes, nanosorbents and nanophotocatalyst based approaches to remove pollutants from wastewater are eco-friendly and efficient, but they require more energy, more investment in order to purify the wastewater. There are many challenges and issues of wastewater treatment. Some precautions are also required to keep away from ecological and health issues. New modern equipment for wastewater treatment should be flexible, low cost and efficient for the commercialization purpose. Full article

(This article belongs to the Special Issue Water Treatment with New Nanomaterials)

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11 pages, 1659 KiB

Open AccessEditor’s ChoiceArticle

Metagenomics Uncovers a Core SAR11 Population in Brackish Surface Waters of the Baltic Sea

by Poorna Weerarathna Vidanage, Seok-Oh Ko and Seungdae Oh

Water 2020, 12(2), 501; https://doi.org/10.3390/w12020501 - 12 Feb 2020

Cited by 7 | Viewed by 3136

Abstract

The Baltic Sea represents one of the largest brackish ecosystems where various environmental factors control dynamic seasonal shifts in the structure, diversity, and function of the planktonic microbial communities. In this study, despite seasonal fluctuations, several bacterial populations (<2% of the total OTUs) [...] Read more.

The Baltic Sea represents one of the largest brackish ecosystems where various environmental factors control dynamic seasonal shifts in the structure, diversity, and function of the planktonic microbial communities. In this study, despite seasonal fluctuations, several bacterial populations (<2% of the total OTUs) that are highly dominant (25% of relative abundance) and highly frequently occurring (>85% of occurrence) over four seasons were identified. Mathematical models using occurrence frequency and relative abundance data were able to describe community assembly persisting over time. Further, this work uncovered one of the core bacterial populations phylogenetically affiliated to SAR11 subclade IIIa. The analysis of the hypervariable region of 16S rRNA gene and single copy housekeeping genes recovered from metagenomic datasets suggested that the population was unexpectedly evolutionarily closely related to those inhabiting a mesosaline lacustrine ecosystem rather than other marine/coastal members. Our metagenomic results further revealed that the newly-identified population was the major driver facilitating the seasonal shifts in the overall community structure over the brackish waters of the Baltic Sea. The core community uncovered in this study supports the presence of a brackish water microbiome distinguishable from other marine and freshwater counterparts and will be a useful sentinel for monitoring local/global environmental changes posed on brackish surface waters. Full article

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34 pages, 15236 KiB

Open AccessEditor’s ChoiceArticle

Performance Evaluation of Bias Correction Methods for Climate Change Monthly Precipitation Projections over Costa Rica

by Maikel Mendez, Ben Maathuis, David Hein-Griggs and Luis-Fernando Alvarado-Gamboa

Water 2020, 12(2), 482; https://doi.org/10.3390/w12020482 - 11 Feb 2020

Cited by 148 | Viewed by 13512

Abstract

Six bias correction (BC) methods; delta-method (DT), linear scaling (LS), power transformation of precipitation (PTR), empirical quantile mapping (EQM), gamma quantile mapping (GQM) and gamma-pareto quantile mapping (GPQM) were applied to adjust the biases of historical monthly precipitation outputs from five General Circulation [...] Read more.

Six bias correction (BC) methods; delta-method (DT), linear scaling (LS), power transformation of precipitation (PTR), empirical quantile mapping (EQM), gamma quantile mapping (GQM) and gamma-pareto quantile mapping (GPQM) were applied to adjust the biases of historical monthly precipitation outputs from five General Circulation Models (GCMs) dynamically downscaled by two Regional Climate Models (RCMs) for a total of seven different GCM-RCM pairs over Costa Rica. High-resolution gridded precipitation observations were used for the control period 1951–1980 and validated over the period 1981–1995. Results show that considerable biases exist between uncorrected GCM-RCM outputs and observations, which largely depend on GCM-RCM pair, seasonality, climatic region and spatial resolution. After the application of bias correction, substantial biases reductions and comparable performances among most BC methods were observed for most GCM-RCM pairs; with EQM and DT marginally outperforming the remaining methods. Consequently, EQM and DT were selectively applied to correct the biases of precipitation projections from each individual GCM-RCM pair for a near-future (2011–2040), mid-future (2041–2070) and far-future (2071–2100) period under Representative Concentration Pathways (RCPs) 2.6, 4.5 and 8.5 using the control period 1961–1990. Results from the bias-corrected future ensemble-mean anticipate a marked decreasing trend in precipitation from near to far-future periods during the dry season (December, January, February (DJF) and March, April, May (MAM)) for RCP4.5 and 8.5; with pronounced drier conditions for those climatic regions draining towards the Pacific Ocean. In contrast, mostly wetter conditions are expected during the dry season under RCP2.6, particularly for the Caribbean region. In most of the country, the greatest decrease in precipitation is projected at the beginning of the rainy season (June, July, August (JJA)) for the far-future period under RCP8.5, except for the Caribbean region where mostly wetter conditions are anticipated. Regardless of future period, slight increases in precipitation with higher radiative forcing are expected for SON excluding the Caribbean region, where precipitation is likely to increase with increasing radiative forcing and future period. This study demonstrates that bias correction should be considered before direct application of GCM-RCM precipitation projections over complex territories such as Costa Rica. Full article

(This article belongs to the Section Hydrology)

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