Next Issue
Previous Issue

E-Mail Alert

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

Journal Browser

Journal Browser

Table of Contents

Water, Volume 9, Issue 10 (October 2017)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Cover Story The Icó-Mandantes Bay is one of the major branches of the Itaparica Reservoir (Sub-Middle São [...] Read more.
View options order results:
result details:
Displaying articles 1-90
Export citation of selected articles as:

Editorial

Jump to: Research, Review, Other

Open AccessFeature PaperEditorial Water–Soil–Vegetation Dynamic Interactions in Changing Climate
Water 2017, 9(10), 740; doi:10.3390/w9100740
Received: 10 August 2017 / Revised: 22 September 2017 / Accepted: 26 September 2017 / Published: 28 September 2017
PDF Full-text (396 KB) | HTML Full-text | XML Full-text
Abstract
Previous studies of land degradation, topsoil erosion, and hydrologic alteration typically focus on these subjects individually, missing important interrelationships among these important aspects of the Earth’s system. However, an understanding of water–soil–vegetation dynamic interactions is needed to develop practical and effective solutions to
[...] Read more.
Previous studies of land degradation, topsoil erosion, and hydrologic alteration typically focus on these subjects individually, missing important interrelationships among these important aspects of the Earth’s system. However, an understanding of water–soil–vegetation dynamic interactions is needed to develop practical and effective solutions to sustain the globe’s eco-environment and grassland agriculture, which depends on grasses, legumes, and other fodder or soil-building crops. This special issue is intended to be a platform for a discussion of the relevant scientific findings based on experimental and/or modeling studies. Its 12 peer-reviewed articles present data, novel analysis/modeling approaches, and convincing results of water–soil–vegetation interactions under historical and future climates. Two of the articles examine how lake/pond water quality is related to human activity and climate. Overall, these articles can serve as important references for future studies to further advance our understanding of how water, soil, and vegetation interactively affect the health and productivity of the Earth’s ecosystem. Full article
(This article belongs to the Special Issue Water-Soil-Vegetation Dynamic Interactions in Changing Climate)
Figures

Figure 1

Open AccessEditorial Significance of the China Meteorological Assimilation Driving Datasets for the SWAT Model (CMADS) of East Asia
Water 2017, 9(10), 765; doi:10.3390/w9100765
Received: 26 August 2017 / Revised: 16 September 2017 / Accepted: 30 September 2017 / Published: 8 October 2017
PDF Full-text (187 KB) | HTML Full-text | XML Full-text
Abstract
The high degree of spatial variability in climate conditions, and a lack of meteorological data for East Asia, present challenges to conducting surface water research in the context of the hydrological cycle. In addition, East Asia is facing pressure from both water resource
[...] Read more.
The high degree of spatial variability in climate conditions, and a lack of meteorological data for East Asia, present challenges to conducting surface water research in the context of the hydrological cycle. In addition, East Asia is facing pressure from both water resource scarcity and water pollution. The consequences of water pollution have attracted public concern in recent years. The low frequency and difficulty of monitoring water quality present challenges to understanding the continuous spatial distributions of non-point source pollution mechanisms in East Asia. The China Meteorological Assimilation Driving Datasets for the Soil and Water Assessment Tool (SWAT) model (CMADS) was developed to provide high-resolution, high-quality meteorological data for use by the scientific community. Applying CMADS can significantly reduce the meteorological input uncertainty and improve the performance of non-point source pollution models, since water resources and non-point source pollution can be more accurately localised. In addition, researchers can make use of high-resolution time series data from CMADS to conduct spatial- and temporal-scale analyses of meteorological data. This Special Issue, “Application of the China Meteorological Assimilation Driving Datasets for the SWAT Model (CMADS) in East Asia”, provides a platform to introduce recent advances in the modelling of water quality and quantity in watersheds using CMADS and hydrological models, and underscores its application to a wide range of topics. Full article
Open AccessFeature PaperEditorial Water Economics and Policy
Water 2017, 9(10), 801; doi:10.3390/w9100801
Received: 12 September 2017 / Revised: 12 October 2017 / Accepted: 12 October 2017 / Published: 18 October 2017
PDF Full-text (209 KB) | HTML Full-text | XML Full-text
Abstract
Economics plays a double role in the field of water management, firstly as a powerful analytical tool supporting water allocation and policy decisions, and secondly in the form of policy instruments (water pricing, markets, etc.). This Special Issue presents a platform for sharing
[...] Read more.
Economics plays a double role in the field of water management, firstly as a powerful analytical tool supporting water allocation and policy decisions, and secondly in the form of policy instruments (water pricing, markets, etc.). This Special Issue presents a platform for sharing results connecting excellent interdisciplinary research applied to different regional and sectoral problems around the world. The 22 peer-reviewed papers collected in this Special Issue have been grouped into five broad categories: Water valuation and accounting; Economic instruments; Cost effectiveness and cost-benefit analysis; and Water productivity and Governance. They are briefly presented. Full article
(This article belongs to the Special Issue Water Economics and Policy)
Open AccessFeature PaperEditorial Adaptation Strategies for Water Resources: Criteria for Research
Water 2017, 9(10), 805; doi:10.3390/w9100805
Received: 6 September 2017 / Revised: 13 October 2017 / Accepted: 17 October 2017 / Published: 19 October 2017
PDF Full-text (202 KB) | HTML Full-text | XML Full-text
Abstract
The Paris Agreement presents new fields of research related to the adaptation strategies to climate change. A challenge for future research consists in developing context-specific guidelines to support adaptation. This Special Issue on “Adaptation strategy to climate change for water resources” is born
[...] Read more.
The Paris Agreement presents new fields of research related to the adaptation strategies to climate change. A challenge for future research consists in developing context-specific guidelines to support adaptation. This Special Issue on “Adaptation strategy to climate change for water resources” is born in this context. It contains 15 scientific studies facing a diversity of issues inherent to the adaptation strategies for water resources. This editorial analyses how the authors of this collection of papers decided to develop and present their research in order to identify criteria to contribute defining, in a near future, standardized approaches and practices for adaptation studies. Papers have been categorized in two major fields: “Studies for the development of adaptation scenarios” and “Studies for the development of adaptation solutions”. Papers belonging to both categories are generally found missing to treat the ‘uncertainty’ issues arising and the implementation of the proposed adaptation strategies. Studies investigating future adaptation scenarios are generally found to be unbalanced in favor of the assessment of future impacts on water resources and less towards the provision of adaptation scenarios. When these studies do not provide elements to manage the specific uncertainty related to the proposed adaptation solutions, at least exploring the uncertainty related to the climatic and impact scenarios is strongly recommended. Studies providing methodological and/or procedural examinations on adaptation solutions are recommended to suitably report the climatic, environmental, and social context for which the action has been developed. A reduction of uncertainty and an easier implementation of proposed measures could be induced from this. Full article
(This article belongs to the Special Issue Adaptation Strategies to Climate Change Impacts on Water Resources)
Open AccessEditorial Water Quality Considerations on the Rise as the Use of Managed Aquifer Recharge Systems Widens
Water 2017, 9(10), 808; doi:10.3390/w9100808
Received: 19 September 2017 / Revised: 8 October 2017 / Accepted: 17 October 2017 / Published: 22 October 2017
PDF Full-text (193 KB) | HTML Full-text | XML Full-text
Abstract
Managed Aquifer Recharge (MAR) is a promising method of increasing water availability in water stressed areas by subsurface infiltration and storage, to overcome periods of drought, and to stabilize or even reverse salinization of coastal aquifers. Moreover, MAR could be a key technique
[...] Read more.
Managed Aquifer Recharge (MAR) is a promising method of increasing water availability in water stressed areas by subsurface infiltration and storage, to overcome periods of drought, and to stabilize or even reverse salinization of coastal aquifers. Moreover, MAR could be a key technique in making alternative water resources available, such as reuse of communal effluents for agriculture, industry and even indirect potable reuse. As exemplified by the papers in this Special Issue, consideration of water quality plays a major role in developing the full potential for MAR application, ranging from the improvement of water quality to operational issues (e.g., well clogging) or sustainability concerns (e.g., infiltration of treated waste water). With the application of MAR expanding into a wider range of conditions, from deserts to urban and coastal areas, and purposes, from large scale strategic storage of desalinated water and the reuse of waste water, the importance of these considerations are on the rise. Addressing these appropriately will contribute to a greater understanding, operational reliability and acceptance of MAR applications, and lead to a range of engineered MAR systems that help increase their effectiveness to help secure the availability of water at the desired quality for the future. Full article
(This article belongs to the Special Issue Water Quality Considerations for Managed Aquifer Recharge Systems)
Open AccessEditorial Land Use, Climate, and Water Resources—Global Stages of Interaction
Water 2017, 9(10), 815; doi:10.3390/w9100815
Received: 13 September 2017 / Revised: 17 October 2017 / Accepted: 19 October 2017 / Published: 24 October 2017
PDF Full-text (512 KB) | HTML Full-text | XML Full-text
Abstract
Land use and climate change can accelerate the depletion of freshwater resources that support humans and ecosystem services on a global scale. Here, we briefly review studies from around the world, and highlight those in this special issue. We identify stages that characterize
[...] Read more.
Land use and climate change can accelerate the depletion of freshwater resources that support humans and ecosystem services on a global scale. Here, we briefly review studies from around the world, and highlight those in this special issue. We identify stages that characterize increasing interaction between land use and climate change. During the first stage, hydrologic modifications and the built environment amplify overland flow via processes associated with runoff-dominated ecosystems (e.g., soil compaction, impervious surface cover, drainage, and channelization). During the second stage, changes in water storage impact the capacity of ecosystems to buffer extremes in water quantity and quality (e.g., either losses in snowpack, wetlands, and groundwater recharge or gains in water and nutrient storage behind dams in reservoirs). During the third stage, extremes in water quantity and quality contribute to losses in ecosystem services and water security (e.g., clean drinking water, flood mitigation, and habitat availability). During the final stage, management and restoration strategies attempt to regain lost ecosystem structure, function, and services but need to adapt to climate change. By anticipating the increasing interaction between land use and climate change, intervention points can be identified, and management strategies can be adjusted to improve outcomes for realistic expectations. Overall, global water security cannot be adequately restored without considering an increasing interaction between land use and climate change across progressive stages and our ever-increasing human domination of the water cycle from degradation to ecosystem restoration. Full article
(This article belongs to the Special Issue Land Use, Climate, and Water Resources)
Figures

Figure 1

Research

Jump to: Editorial, Review, Other

Open AccessArticle Assessing Agricultural Drought in the Anthropocene: A Modified Palmer Drought Severity Index
Water 2017, 9(10), 725; doi:10.3390/w9100725
Received: 17 July 2017 / Revised: 10 September 2017 / Accepted: 16 September 2017 / Published: 26 September 2017
PDF Full-text (8042 KB) | HTML Full-text | XML Full-text
Abstract
In the current human-influenced era, drought is initiated by natural and human drivers, and human activities are as integral to drought as meteorological factors. In large irrigated agricultural regions with high levels of human intervention, where the natural farmland soil moisture has usually
[...] Read more.
In the current human-influenced era, drought is initiated by natural and human drivers, and human activities are as integral to drought as meteorological factors. In large irrigated agricultural regions with high levels of human intervention, where the natural farmland soil moisture has usually been changed significantly by high-frequency irrigation, the actual severity of agricultural drought is distorted in traditional drought indices. In this work, an agricultural drought index that considering irrigation processes based on the Palmer drought severity index (IrrPDSI) was developed to interpret the real agricultural drought conditions in irrigated regions, with a case study in the Haihe River Basin in northeast China. The water balance model in the original PDSI was revised by an auto-irrigation threshold method combined with a local irrigation schedule. The auto-irrigation setting of the index was used by taking irrigation quotas during specific growth stages of specific crops (wheat–corn) into consideration. A series of weekly comparative analyses are as follows: (1) The soil moisture analyses showed that soil moisture values calculated by the modified water balance model were close to the real values; (2) The statistical analyses indicated that most of the stations in the study area based on IrrPDSI had nearly normal distributed values; (3) The time series and spatial analyses showed that the results of the IrrPDSI-reported dry-wet evaluation were more consistent with documented real conditions. All the results revealed that IrrPDSI performed well when used to assess agricultural drought. This work has direct significance for agricultural drought management in large irrigated areas heavily disturbed by human activity. Full article
(This article belongs to the Special Issue Drought Monitoring, Forecasting, and Risk Assessment)
Figures

Figure 1

Open AccessArticle Removing Organic Matter and Nutrients from Swine Wastewater after Anaerobic–Aerobic Treatment
Water 2017, 9(10), 726; doi:10.3390/w9100726
Received: 2 August 2017 / Revised: 7 September 2017 / Accepted: 16 September 2017 / Published: 25 September 2017
PDF Full-text (969 KB) | HTML Full-text | XML Full-text
Abstract
Anaerobic digesters generate effluent containing about 3000 mg L−1 of organic matter in terms of chemical oxygen demand (COD). This effluent must be treated before being reused or discharged into the environment. The objective of this study was to evaluate the efficiency
[...] Read more.
Anaerobic digesters generate effluent containing about 3000 mg L−1 of organic matter in terms of chemical oxygen demand (COD). This effluent must be treated before being reused or discharged into the environment. The objective of this study was to evaluate the efficiency of a trickling filter packed with red volcanic rock for the treatment of anaerobic digester effluent with COD concentrations of around 3000 mg L−1. The trickling filter consisted of an aluminum cylinder, 2 mm thick, 3 m high, and 1 m in diameter. To evaluate the efficiency of the treatment system, there were three experimental runs, each lasting 20 days (d). The predictor variable was the initial COD concentration, which ranged from 2002 to 3074 mg L−1. The hydraulic retention time was 9 h. The influent flow was 2.2 L min−1, which amounts to a hydraulic load of 4033 m3 m−2 day−1 and an organic load of 0.006342 to 0.009738 kg m−3 day−1 of COD. Independent of the initial concentration, COD removal efficiency was very high, varying from 90 to 96%. Final effluents met all the maximum permissible limits to be used as irrigation water, as well as for its release into natural or artificial water reservoirs, stored for agricultural crop irrigation. Full article
(This article belongs to the Special Issue Recent Advances in Water Management: Saving, Treatment and Reuse)
Figures

Figure 1

Open AccessArticle Land–Atmosphere Exchange of Water and Heat in the Arid Mountainous Grasslands of Central Asia during the Growing Season
Water 2017, 9(10), 727; doi:10.3390/w9100727
Received: 1 August 2017 / Revised: 5 September 2017 / Accepted: 18 September 2017 / Published: 28 September 2017
PDF Full-text (6358 KB) | HTML Full-text | XML Full-text
Abstract
Arid grassland ecosystems are widely distributed across Central Asia. However, there is a lack of research and observations of the land–atmosphere exchange of water and heat in the arid grasslands in this region, particularly over complex surfaces. In this study, systematic observations were
[...] Read more.
Arid grassland ecosystems are widely distributed across Central Asia. However, there is a lack of research and observations of the land–atmosphere exchange of water and heat in the arid grasslands in this region, particularly over complex surfaces. In this study, systematic observations were conducted from 2013 to 2015 using an HL20 Bowen ratio and TDR300 and WatchDog1400 systems to determine the characteristics of these processes during the growing season (April–October) of the arid mountainous grasslands of this region. (1) The latent heat flux (Le) was lower than the sensible heat flux (He) overall, and a small transient decrease in Le was observed before its daytime maximum; daily comparative variations in both fluxes were closely related to vegetation growth. (2) Evapotranspiration (ET) showed substantial variation across different years, seasons and months, and monthly variations in ET were closely related to vegetation growth. Water condensation (Q) was low and relatively stable. Relatively high levels of soil water were measured in spring followed by a decreasing trend. The land–atmosphere exchange of water and heat during the growing season in this region was closely associated with phenology, available precipitation and terrain. This study provides data support for the scientific management of arid mountainous grasslands. Full article
Figures

Figure 1

Open AccessArticle Management Scenarios of the Grand Ethiopian Renaissance Dam and Their Impacts under Recent and Future Climates
Water 2017, 9(10), 728; doi:10.3390/w9100728
Received: 7 August 2017 / Revised: 19 September 2017 / Accepted: 20 September 2017 / Published: 22 September 2017
PDF Full-text (745 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Close to the border with Sudan, Ethiopia is currently building the largest hydroelectric power plant in Africa with a storage volume corresponding to approximately 1.5 years of the mean discharges of the Blue Nile. This endeavor is controversially debated in the public and
[...] Read more.
Close to the border with Sudan, Ethiopia is currently building the largest hydroelectric power plant in Africa with a storage volume corresponding to approximately 1.5 years of the mean discharges of the Blue Nile. This endeavor is controversially debated in the public and the scientific literature. Contributing to this discussion, by shading some light on climate change issues, an eco-hydrological model, equipped with a reservoir module, was applied to investigate downstream hydrological impacts during filling and regular operation, the latter considering climate change projected by an ensemble of 10 global and regional climate models. Our results show that at the earliest after 20 months, the dam could produce hydroelectric power. Full supply level may be reached after four years or not at all, depending on filling policies and assumptions of seepage rates. Under recent hydro-climatic conditions, the dam may produce 13 TWh a , which is below the envisaged target of 15.7 TWh a . The ensemble mean suggests slightly increasing hydropower production in the future. Almost independently of the operation rules, the highly variable discharge regime will be significantly altered to a regime with almost equal flows each month. Achieving a win-win situation for all riparian countries requires a high level of cooperation in managing the Eastern Nile water resources. Full article
Figures

Open AccessFeature PaperArticle Calculation of Steady-State Evaporation for an Arbitrary Matric Potential at Bare Ground Surface
Water 2017, 9(10), 729; doi:10.3390/w9100729
Received: 10 July 2017 / Revised: 13 September 2017 / Accepted: 19 September 2017 / Published: 22 September 2017
PDF Full-text (1465 KB) | HTML Full-text | XML Full-text
Abstract
Evaporation from soil columns in the presence of a water table is a long lasting subject that has received great attention for many decades. Available analytical studies on the subject often involve an assumption that the potential evaporation rate is much less than
[...] Read more.
Evaporation from soil columns in the presence of a water table is a long lasting subject that has received great attention for many decades. Available analytical studies on the subject often involve an assumption that the potential evaporation rate is much less than the saturated hydraulic conductivity of the soil. In this study, we develop a new semi-analytical method to estimate the evaporation rate for an arbitrary matric potential head at bare soil surface without assuming that the potential evaporation rate is much less than the saturated hydraulic conductivity of the soil. The results show that the evaporation rates calculated by the new solutions fit well with the HYDRUS-1D simulation. The new solutions also can reproduce the results of potential evaporation rate calculated from previous equations under the special condition of an infinite matric potential head at bare soil surface. The developed new solutions expand our present knowledge of evaporation estimation at bare ground surface to more general field conditions. Full article
Figures

Figure 1

Open AccessArticle Investigation of Algal Biotoxin Removal during SWRO Desalination through a Materials Flow Analysis
Water 2017, 9(10), 730; doi:10.3390/w9100730
Received: 19 August 2017 / Revised: 13 September 2017 / Accepted: 19 September 2017 / Published: 23 September 2017
PDF Full-text (1665 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The operation of seawater reverse osmosis (SWRO) desalination facilities has become challenged by the increasing frequency and severity of harmful algal blooms (HABs). The efficiency of algal toxins removal during SWRO and pretreatment processes has critical human health implications. Therefore, a probabilistic materials
[...] Read more.
The operation of seawater reverse osmosis (SWRO) desalination facilities has become challenged by the increasing frequency and severity of harmful algal blooms (HABs). The efficiency of algal toxins removal during SWRO and pretreatment processes has critical human health implications. Therefore, a probabilistic materials flow analysis (pMFA) was developed to predict the removal of algal toxins in source water by various pretreatment configurations and operations during SWRO desalination. The results demonstrated that an appreciable quantity of toxins exists in the SWRO permeate (ng/L–µg/L levels), the backwash of pretreatment, and final brine rejects (µg/L–mg/L levels). Varying the pretreatment train configuration resulted in statistically significant differences in toxin removals, where higher removal efficiencies were evidenced in systems employing microfiltration/ultrafiltration (MF/UF) over granular media filtration (GMF). However, this performance depended on operational practices including coagulant addition and transmembrane pressures of MF/UF systems. Acute human health risks during lifetime exposure to algal toxins from ingestion of desalinated water were benign, with margins of safety ranging from 100 to 4000. This study highlights the importance of pretreatment steps during SWRO operation in the removal of algal toxins for managing marine HABs. Full article
(This article belongs to the Special Issue Sustainable Water Supply through Desalination and Wastewater Reuse)
Figures

Open AccessArticle The Free-Swimming Device Leakage Detection in Plastic Water-filled Pipes through Tuning the Wavelet Transform to the Underwater Acoustic Signals
Water 2017, 9(10), 731; doi:10.3390/w9100731
Received: 25 July 2017 / Revised: 8 September 2017 / Accepted: 19 September 2017 / Published: 23 September 2017
PDF Full-text (6939 KB) | HTML Full-text | XML Full-text
Abstract
The conventional fixed acoustic sensors leak detection methods have been demonstrated to be very practical for locating leakages in water distribution pipelines. However, these methods demand proper installation of sensors, and therefore cannot be implemented on buried long water distribution pipelines for condition
[...] Read more.
The conventional fixed acoustic sensors leak detection methods have been demonstrated to be very practical for locating leakages in water distribution pipelines. However, these methods demand proper installation of sensors, and therefore cannot be implemented on buried long water distribution pipelines for condition assessment, early leak detection, and the estimation of leak size effect. Due to these limitations, a free-swimming device is developed. The free-swimming device with the potential of high acoustic sensitivity is capable of detecting the small underwater leakages in the plastic water-filled pipes. Despite the fact that a number of factors influence the underwater acoustic signals, such as water flow noise. Therefore, the interpretation of the leakage and influence of leakage size is considerably challenging from the underwater measured signals. The new method is proposed for reliable leakage detection by tuning the wavelet transform to underwater water acoustic signals. In this method, firstly, Short-Time Fourier Transforms (STFT) of underwater acoustic signals over a relatively long time-interval is monitored to capture the leakage-signals signature. The captured signals efficiently lead in the selection of mother wavelet (tuned wavelet) for the excellent signal localization in the time-frequency domain. Finally, the acoustic signals are analyzed in the tuned wavelet transform to detect the events. In this paper, the practical application of the proposed method, the controlled experiments are designed, and acoustic signals are collected from an experimental setup by launching the free-swimming device. The measured acoustic signals are used to identify the leakage-signals signature from unwanted interfering signals (instantaneous pipe vibrations, water flow noise, pipe's natural frequencies, and background noise). The evaluation of results validated that the free-swimming device and the tuned wavelet transform together can efficiently lead to reliable underwater leakage detection, as well as the influence of the leakage size in plastic water-filled pipes. Full article
Figures

Figure 1

Open AccessArticle Simulating Climate Change Induced Thermal Stress in Coldwater Fish Habitat Using SWAT Model
Water 2017, 9(10), 732; doi:10.3390/w9100732
Received: 30 June 2017 / Revised: 31 August 2017 / Accepted: 15 September 2017 / Published: 25 September 2017
PDF Full-text (5446 KB) | HTML Full-text | XML Full-text
Abstract
Climate studies have suggested that inland stream temperatures and average streamflows will increase over the next century in New England, thereby putting aquatic species sustained by coldwater habitats at risk. This study uses the Soil and Water Assessment Tool (SWAT) to simulate historical
[...] Read more.
Climate studies have suggested that inland stream temperatures and average streamflows will increase over the next century in New England, thereby putting aquatic species sustained by coldwater habitats at risk. This study uses the Soil and Water Assessment Tool (SWAT) to simulate historical streamflow and stream temperatures within three forested, baseflow-driven watersheds in Rhode Island, USA followed by simulations of future climate scenarios for comparison. Low greenhouse gas emission scenarios are based on the 2007 International Panel on Climate Change Special Report on Emissions Scenarios (SRES) B1 scenario and the high emissions are based on the SRES A1fi scenario. The output data are analyzed to identify daily occurrences where brook trout (Salvelinus fontinalis) are exposed to stressful events, defined herein as any day where Q25 or Q75 flows occur simultaneously with stream temperatures exceeding 21 °C. Results indicate that under both high- and low-emission greenhouse gas scenarios, coldwater fish species such as brook trout will be increasingly exposed to stressful events. The percent chance of stressful event occurrence increased by an average of 6.5% under low-emission scenarios and by 14.2% under high-emission scenarios relative to the historical simulations. Full article
Figures

Figure 1

Open AccessArticle Effects of Climate, Limnological Features and Watershed Clearcut Logging on Long-Term Variation in Zooplankton Communities of Boreal Shield Lakes
Water 2017, 9(10), 733; doi:10.3390/w9100733
Received: 12 August 2017 / Revised: 8 September 2017 / Accepted: 20 September 2017 / Published: 25 September 2017
PDF Full-text (2129 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In Canada, climate change and forest harvesting may both threaten the ecological integrity of boreal lakes. To disentangle the effects of natural variation in climate and lake environments from those of logging, we evaluated long-term variation (1991–2003) in zooplankton communities of six boreal
[...] Read more.
In Canada, climate change and forest harvesting may both threaten the ecological integrity of boreal lakes. To disentangle the effects of natural variation in climate and lake environments from those of logging, we evaluated long-term variation (1991–2003) in zooplankton communities of six boreal lakes in Ontario. We monitored concomitantly changes in zooplankton abundance and composition in three undisturbed and three harvested lakes, five years prior and eight years after watershed clearcut logging. We tested the hypothesis that long-term natural variation in climate and lake environments will be more important drivers of zooplankton community changes than short-term impacts of logging. We used space/time interaction tests and asymmetric eigenvector maps to model zooplankton responses to environmental changes and logging. Year-to-year variation in zooplankton abundance and composition were almost an order of magnitude whereas among-lake variation was stable through time. Breakpoints in time series of zooplankton in each lake were not directly related to logging. Climatic and limnological features were the most important drivers of long-term variation in the zooplankton community, shading the effect of logging. These results highlight the need to better understand the pressures exerted by climate change on boreal lake ecosystems in the context of anthropogenic pressure, such as logging. Full article
(This article belongs to the Special Issue Ecological Responses of Lakes to Climate Change)
Figures

Figure 1

Open AccessArticle A Comparative Study of Potential Evapotranspiration Estimation by Eight Methods with FAO Penman–Monteith Method in Southwestern China
Water 2017, 9(10), 734; doi:10.3390/w9100734
Received: 1 August 2017 / Revised: 10 September 2017 / Accepted: 19 September 2017 / Published: 28 September 2017
PDF Full-text (3096 KB) | HTML Full-text | XML Full-text
Abstract
Potential evapotranspiration (PET) is crucial for water resources assessment. In this regard, the FAO (Food and Agriculture Organization)–Penman–Monteith method (PM) is commonly recognized as a standard method for PET estimation. However, due to requirement of detailed meteorological data, the application of PM is
[...] Read more.
Potential evapotranspiration (PET) is crucial for water resources assessment. In this regard, the FAO (Food and Agriculture Organization)–Penman–Monteith method (PM) is commonly recognized as a standard method for PET estimation. However, due to requirement of detailed meteorological data, the application of PM is often constrained in many regions. Under such circumstances, an alternative method with similar efficiency to that of PM needs to be identified. In this study, three radiation-based methods, Makkink (Mak), Abtew (Abt), and Priestley–Taylor (PT), and five temperature-based methods, Hargreaves–Samani (HS), Thornthwaite (Tho), Hamon (Ham), Linacre (Lin), and Blaney–Criddle (BC), were compared with PM at yearly and seasonal scale, using long-term (50 years) data from 90 meteorology stations in southwest China. Indicators, viz. (videlicet) Nash–Sutcliffe efficiency (NSE), relative error (Re), normalized root mean squared error (NRMSE), and coefficient of determination (R2) were used to evaluate the performance of PET estimations by the above-mentioned eight methods. The results showed that the performance of the methods in PET estimation varied among regions; HS, PT, and Abt overestimated PET, while others underestimated. In Sichuan basin, Mak, Abt and HS yielded similar estimations to that of PM, while, in Yun-Gui plateau, Abt, Mak, HS, and PT showed better performances. Mak performed the best in the east Tibetan Plateau at yearly and seasonal scale, while HS showed a good performance in summer and autumn. In the arid river valley, HS, Mak, and Abt performed better than the others. On the other hand, Tho, Ham, Lin, and BC could not be used to estimate PET in some regions. In general, radiation-based methods for PET estimation performed better than temperature-based methods among the selected methods in the study area. Among the radiation-based methods, Mak performed the best, while HS showed the best performance among the temperature-based methods. Full article
Figures

Figure 1

Open AccessArticle Regional Climate Change Impacts on Irrigation Vulnerable Season Shifts in Agricultural Water Availability for South Korea
Water 2017, 9(10), 735; doi:10.3390/w9100735
Received: 10 August 2017 / Revised: 22 September 2017 / Accepted: 25 September 2017 / Published: 26 September 2017
PDF Full-text (4780 KB) | HTML Full-text | XML Full-text
Abstract
Reservoirs are principal water resources that supply irrigation water to paddy fields and play an important role in water resources management in South Korea. For optimal irrigation reservoir operation and management, it is necessary to determine the duration of irrigation water shortages. Management
[...] Read more.
Reservoirs are principal water resources that supply irrigation water to paddy fields and play an important role in water resources management in South Korea. For optimal irrigation reservoir operation and management, it is necessary to determine the duration of irrigation water shortages. Management of reservoir operation and irrigation scheduling should take into consideration essential variables that include the water supply in a reservoir and the water demand in the associated irrigation district. The agricultural water supply and demand show different patterns based on the variability and uncertainty of meteorological and hydrological phenomena. The duration of excessive water supply can be quantitatively determined through analysis of deviations and changes in the timing of agricultural water supply and demand. In this study, we introduce an approach to assess the vulnerable seasons of paddy irrigation to enable more effective operation and management of reservoirs. The vulnerable seasons were evaluated through comparison of the potential water supply capacity and irrigation water requirements based on water budget analysis via a time series change analysis. We have assessed the changing in the total duration and duration shifts of the vulnerable irrigation seasons for four agricultural reservoirs using past observed data (1981–2010) from meteorological stations maintained by the Korea Meteorological Administration (KMA) and projected climate change scenarios (2011–2100) as depicted by the Representative Concentration Pathways (RCPs) emission scenarios. For irrigation vulnerable seasons under both the RCP 4.5 and RCP 8.5 scenarios, the results showed periods of significant increases in which total vulnerable seasons compared to the historical period; the longest duration of vulnerability occurred during the 2071–2100 period under the RCP 8.5. Identification of the vulnerable seasons for paddy irrigation can be applied in agricultural water management to more effectively manage reservoir operation during irrigation periods with climate changes. Full article
Figures

Figure 1

Open AccessArticle Spatial Analysis of High-Resolution Radar Rainfall and Citizen-Reported Flash Flood Data in Ultra-Urban New York City
Water 2017, 9(10), 736; doi:10.3390/w9100736
Received: 25 July 2017 / Revised: 9 September 2017 / Accepted: 18 September 2017 / Published: 27 September 2017
PDF Full-text (9720 KB) | HTML Full-text | XML Full-text
Abstract
New York City (NYC) is an ultra-urban region, with over 50% impervious cover and buried stream channels. Traditional flood studies rely on the presence of stream gages to detect flood stage and discharge, but these methods cannot be used in ultra-urban areas. Here
[...] Read more.
New York City (NYC) is an ultra-urban region, with over 50% impervious cover and buried stream channels. Traditional flood studies rely on the presence of stream gages to detect flood stage and discharge, but these methods cannot be used in ultra-urban areas. Here we create a high-resolution radar rainfall dataset for NYC and utilize citizen and expert reports of flooding throughout the city to study flash flooding in NYC. Results indicate that interactions between the urban area and land–sea boundary have an important impact on the spatial variability of both heavy rainfall and flooding, sometimes in contrast to results obtained for other cities. Top days of daily and hourly rainfall exhibit a rainfall maximum over the city center and an extended region of higher rainfall downwind of the city. The mechanism for flooding appears to vary across the city, with high groundwater tables influencing more coastal areas and high rain rates or large rain volumes influencing more inland areas. There is also a strong relationship between sewer type and flood frequency, with fewer floods observed in combined sewer areas. Flooding is driven by maximum one-hour to one-day rainfall, which is often substantially less rain than observed for the city-wide daily maximum. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Application of the Support Vector Regression Method for Turbidity Assessment with MODIS on a Shallow Coral Reef Lagoon (Voh-Koné-Pouembout, New Caledonia)
Water 2017, 9(10), 737; doi:10.3390/w9100737
Received: 23 June 2017 / Revised: 11 September 2017 / Accepted: 19 September 2017 / Published: 27 September 2017
PDF Full-text (8474 KB) | HTML Full-text | XML Full-text
Abstract
Particle transport by erosion from ultramafic lands in pristine tropical lagoons is a crucial problem, especially for the benthic and pelagic biodiversity associated with coral reefs. Satellite imagery is useful for assessing particle transport from land to sea. However, in the oligotrophic and
[...] Read more.
Particle transport by erosion from ultramafic lands in pristine tropical lagoons is a crucial problem, especially for the benthic and pelagic biodiversity associated with coral reefs. Satellite imagery is useful for assessing particle transport from land to sea. However, in the oligotrophic and shallow waters of tropical lagoons, the bottom reflection of downwelling light usually hampers the use of classical optical algorithms. In order to address this issue, a Support Vector Regression (SVR) model was developed and tested. The proposed application concerns the lagoon of New Caledonia—the second longest continuous coral reef in the world—which is frequently exposed to river plumes from ultramafic watersheds. The SVR model is based on a large training sample of in-situ turbidity values representative of the annual variability in the Voh-Koné-Pouembout lagoon (Western Coast of New Caledonia) during the 2014–2015 period and on coincident satellite reflectance values from MODerate Resolution Imaging Spectroradiometer (MODIS). It was trained with reflectance and two other explanatory parameters—bathymetry and bottom colour. This approach significantly improved the model’s capacity for retrieving the in-situ turbidity range from MODIS images, as compared with algorithms dedicated to deep oligotrophic or turbid waters, which were shown to be inadequate. This SVR model is applicable to the whole shallow lagoon waters from the Western Coast of New Caledonia and it is now ready to be tested over other oligotrophic shallow lagoon waters worldwide. Full article
(This article belongs to the Special Issue Sediment Transport in Coastal Waters)
Figures

Figure 1

Open AccessArticle Strategic Evaluation Tool for Surface Water Quality Management Remedies in Drinking Water Catchments
Water 2017, 9(10), 738; doi:10.3390/w9100738
Received: 6 July 2017 / Revised: 10 September 2017 / Accepted: 22 September 2017 / Published: 27 September 2017
PDF Full-text (2025 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Drinking water catchments (DWC) are under pressure from point and nonpoint source pollution due to the growing human activities. This worldwide challenge is causing number of adverse effects, such as degradation in water quality, ecosystem health, and other economic and social pressures. Different
[...] Read more.
Drinking water catchments (DWC) are under pressure from point and nonpoint source pollution due to the growing human activities. This worldwide challenge is causing number of adverse effects, such as degradation in water quality, ecosystem health, and other economic and social pressures. Different evaluation tools have been developed to achieve sustainable and healthy drinking water catchments. However, a holistic and strategic framework is still required to adequately consider the uncertainty associated with feasible management remedies of surface water quality in drinking water catchments. A strategic framework was developed to adequately consider the uncertainty associated with management remedies for surface water quality in drinking water catchments. A Fuzzy Multiple Criteria Decision Analysis (FMCDA) approach was embedded into a strategic decision support framework to evaluate and rank water quality remediation options within a typical fixed budget constraint faced by bulk water providers. The evaluation framework consists of four core aspects; namely, water quality, environmental, economic and social, and number of associated quantitative and qualitative criteria and sub-criteria. Final remediation strategy ranking was achieved through the application of the Euclidean Distance by the In-center of Centroids (EDIC). Full article
(This article belongs to the Special Issue Water Quality Monitoring and Modeling in Lakes)
Figures

Figure 1

Open AccessArticle Full Scale Sludge Treatment in Reed Beds in Moderate Climate—A Case Study
Water 2017, 9(10), 741; doi:10.3390/w9100741
Received: 9 August 2017 / Revised: 6 September 2017 / Accepted: 19 September 2017 / Published: 28 September 2017
PDF Full-text (1079 KB) | HTML Full-text | XML Full-text
Abstract
The wastewater treatment plant of Wathlingen, Germany, has a design capacity of 20,500 p.e. Since 2000, the sewage sludge has been treated in four reed beds with an area of 3000 m2 each. During this time, three of the four polders were
[...] Read more.
The wastewater treatment plant of Wathlingen, Germany, has a design capacity of 20,500 p.e. Since 2000, the sewage sludge has been treated in four reed beds with an area of 3000 m2 each. During this time, three of the four polders were emptied once and put into operation again, which has allowed for an evaluation of complete operation cycles from startup to sludge removal. This paper comprises data on polder construction and operating results as well as an economic evaluation of construction, operation, and sludge disposal costs. Results show that sludge DS mass may be reduced by at least 23% and at most 52%. Water content was reduced, but the DS concentration of the product excavated was not higher than around 20% DS. Operation experiences proved that the system is very user-friendly and requiring limited maintenance and control work. To make the best use of this technique, it is recommended a separate area for additional storage and dewatering is provided after the sludge from the polders is removed. This allows for the possibility for the operators to determine the appropriate time and conditions for final disposal. Full article
Figures

Figure 1

Open AccessArticle Effects of Intra-Storm Soil Moisture and Runoff Characteristics on Ephemeral Gully Development: Evidence from a No-Till Field Study
Water 2017, 9(10), 742; doi:10.3390/w9100742
Received: 27 August 2017 / Revised: 24 September 2017 / Accepted: 26 September 2017 / Published: 28 September 2017
PDF Full-text (4474 KB) | HTML Full-text | XML Full-text
Abstract
Ephemeral gully erosion, prevalent on agricultural landscapes of the Great Plains, is recognized as a large source of soil loss and a substantial contributor to the sedimentation of small ponds and large reservoirs. Multi-seasonal field studies can provide needed information on ephemeral gully
[...] Read more.
Ephemeral gully erosion, prevalent on agricultural landscapes of the Great Plains, is recognized as a large source of soil loss and a substantial contributor to the sedimentation of small ponds and large reservoirs. Multi-seasonal field studies can provide needed information on ephemeral gully development and its relationship to physical factors associated with field characteristics, rainfall patterns, runoff hydrograph, and management practices. In this study, an ephemeral gully on a no-till cultivated crop field in central Kansas, U.S., was monitored in 2013 and 2014. Data collection included continuous sub-hourly precipitation, soil moisture, soil temperature, and 15 field surveys of cross-sectional profiles in the headcut and channelized parts of the gully. Rainfall excess from a contributing catchment was calculated with the Water Erosion Prediction Project (WEPP) model for all storm events and validated on channel flow measurements. Twelve significant runoff events with hydraulic shear stresses higher than the critical value were identified to potentially cause soil erosion in three out of fourteen survey periods. Analysis of shear stress imposed by peak channel flow on soil surface, antecedent soil moisture condition, and channel shape at individual events provided the basis on which to extend the definition of the critical shear stress function by incorporating the intra-storm changes in soil moisture content. One potential form of this function was suggested and tested with collected data. Similar field studies in other agriculturally-dominated areas and laboratory experiments can develop datasets for a better understanding of the physical mechanisms associated with ephemeral gully progression. Full article
(This article belongs to the Special Issue Streambank Erosion: Monitoring, Modeling and Management)
Figures

Figure 1

Open AccessArticle Variation of Aridity Index and the Role of Climate Variables in the Southwest China
Water 2017, 9(10), 743; doi:10.3390/w9100743
Received: 30 August 2017 / Revised: 24 September 2017 / Accepted: 26 September 2017 / Published: 28 September 2017
PDF Full-text (3742 KB) | HTML Full-text | XML Full-text
Abstract
Aridity index (AI), defined as the ratio of annual potential evapotranspiration to annual precipitation, has been widely applied in dividing climate regimes and monitoring drought events. Investigating variation of AI and the role of climate variables are thus of great significant
[...] Read more.
Aridity index (AI), defined as the ratio of annual potential evapotranspiration to annual precipitation, has been widely applied in dividing climate regimes and monitoring drought events. Investigating variation of AI and the role of climate variables are thus of great significant for managing agricultural water resource and maintaining regional ecosystem stability. In this study, with the well-corrected precipitation records and the optimized parameters in estimating solar radiation, we investigated the variation of AI and its climatic attribution in the Southwest China using the observed climate records from 135 meteorological stations during the period of 1993–2015. The results showed that the AI increased significantly (0.0053 year−1, p < 0.05) from 1993 to 2015 and abruptly increasing occurred around 2002. Approximately 85% of stations showed an increasing trend, while 24% of stations reached up to a significant increasing level, which demonstrated that the Southwest China was getting drier for the recent 20 years. Overall, the AI was most sensitive to maximum air temperature and precipitation with values of 1.11 and −1.00, respectively. The following factors are vapor pressure, solar radiation, minimum temperature, and wind speed. The declining precipitation and ascending maximum air temperature were the key variables in dominating the increase in aridity index during the period of 1993–2015, which contribute 38.98% and 36.26% of AI variation, respectively. Our results highlighted the influence of climate variability on aridity in the Southwest China. Full article
Figures

Figure 1

Open AccessArticle Applying a Simple Analytical Solution to Modelling Wind-Driven Coastal Upwelling of Two-Layered Fluid at the Head of Tokyo Bay, Japan
Water 2017, 9(10), 744; doi:10.3390/w9100744
Received: 4 August 2017 / Revised: 26 September 2017 / Accepted: 26 September 2017 / Published: 29 September 2017
PDF Full-text (4731 KB) | HTML Full-text | XML Full-text
Abstract
Blue tides at the head of Tokyo Bay are a hydro-environmental phenomenon where seawater appears to be milky blue because of the reflection of the sunlight off surface water containing large amounts of sulphur particles. Its appearance is due to the coastal upwelling
[...] Read more.
Blue tides at the head of Tokyo Bay are a hydro-environmental phenomenon where seawater appears to be milky blue because of the reflection of the sunlight off surface water containing large amounts of sulphur particles. Its appearance is due to the coastal upwelling of bottom oxygen-depleted water induced by northeasterly wind-driven circulation. Blue tides cause the death of many shellfish and other aquatic animals across the head of Tokyo Bay and consequently result in substantial economic losses to coastal fisheries. This paper examines the occurrence of wind-driven blue tides in Tokyo Bay, based on a simplified hydrodynamic model and observational analysis. The model assumed a two-layer structure with a wind-driven upper layer and an oxygen-depleted lower layer. In this study, we derived a simple analytical solution to determine a critical wind condition for which the lower layer outcrops at the surface if the wind forcing is sufficiently strong, resulting in the mixing of the two layers and giving rise to blue tide. The results of sensitivity analyses of the analytical solution to all incorporated factors were found to be in accordance with a qualitative understanding of the blue tide phenomenon. More importantly, comparisons of observational data with real cases of blue tide during 1978–2016 and without blue tide during 2003–2016 suggested that this analytical solution was mostly valid. This study would be helpful for gaining a better understanding of the hydro-dynamical mechanism of blue tide. Full article
Figures

Figure 1

Open AccessArticle Integrating Ecological Restoration of Agricultural Non-Point Source Pollution in Poyang Lake Basin in China
Water 2017, 9(10), 745; doi:10.3390/w9100745
Received: 6 August 2017 / Revised: 23 September 2017 / Accepted: 25 September 2017 / Published: 29 September 2017
PDF Full-text (1373 KB) | HTML Full-text | XML Full-text
Abstract
This study addresses the excessive consumption of river basin water from the Poyang Lake area in China. Consumption of water for irrigation, together with the discharge of agricultural non-point source pollution, is seriously affecting the water quality of Poyang Lake. This study assesses
[...] Read more.
This study addresses the excessive consumption of river basin water from the Poyang Lake area in China. Consumption of water for irrigation, together with the discharge of agricultural non-point source pollution, is seriously affecting the water quality of Poyang Lake. This study assesses the application of integrated ecological restoration technology for agricultural non-point source pollution in the Ganfu Plain Area, which is an important agricultural production base in the Poyang Lake basin. The results indicated that the water-fertilizer comprehensive regulation mode for double-cropping rice provided water savings of 10.4% and increased rice yield by 6.5% per hectare. Furthermore, it reduced drainage water pollution by 20.4%, and emissions of ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3-N), total phosphorus (TP), and total nitrogen (TN) from rice paddy surfaces by 18.6%, 11.1%, 15.4%, and 16.0%, respectively. The eco-channel–pond wetland system effectively reduced TN and TP pollutant levels in rice paddy drainage water; the eco-channel reduced TN and TP by 9.3% and 14.0%, respectively; and the pond wetland system showed reductions of 8.6% and 22.9%, respectively. The “three lines of defense” purification technology, including rice field source control, eco-channel interception, and pond wetland purification, removed 29.9% of TN and 44.3% of TP. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Phosphorus Retention by Fly Ash Amended Filter Media in Aged Bioretention Cells
Water 2017, 9(10), 746; doi:10.3390/w9100746
Received: 7 September 2017 / Revised: 26 September 2017 / Accepted: 27 September 2017 / Published: 29 September 2017
PDF Full-text (797 KB) | HTML Full-text | XML Full-text
Abstract
Bioretention cells (BRCs) have shown potential for storm water quantity and quality control. However, the phosphorus (P) removal in BRC has been variable due to differences of soil properties in filter media. The objectives of this research were to identify and evaluate P
[...] Read more.
Bioretention cells (BRCs) have shown potential for storm water quantity and quality control. However, the phosphorus (P) removal in BRC has been variable due to differences of soil properties in filter media. The objectives of this research were to identify and evaluate P accumulation in filter media and to quantify effluent P reduction in BRC. Each cell has a sand and fly ash media designed to remove phosphorous. Filter media were collected in 2014 across the cell surface and to a depth of 0.6 m to quantify the P accumulation. The mean total P (T-P) concentration increased over the seven years of operation, but the changes were not statistically significant. The average Mehlich-3 P (M3-P) and water-soluble P (WS-P) concentrations in the media profiles showed higher P accumulation in the top 0.15 m. The average M3-P and WS-P concentrations between 0.15 m to 0.30 m, and 0.30 m to 0.60 m were variable on all four BRCs media. The media with 5% fly ash significantly retained M3-P and WS-P over the top 0.15 m. Stormwater influent and effluent samples from three of the BRCs monitored over one year showed reductions in both P concentration (68% to 75%) and P mass (76% to 93%). Full article
(This article belongs to the Special Issue Additives in Stormwater Filters for Enhanced Pollutant Removal)
Figures

Figure 1

Open AccessArticle A Novel SWMM Based Algorithm Application to Storm Sewer Network Design
Water 2017, 9(10), 747; doi:10.3390/w9100747
Received: 21 August 2017 / Revised: 23 September 2017 / Accepted: 26 September 2017 / Published: 29 September 2017
PDF Full-text (1580 KB) | HTML Full-text | XML Full-text
Abstract
An automated algorithm based on the dynamic hydrological and hydraulic simulation modules in Storm Water Management Model (SWMM) was developed to aid the design of storm sewer networks, provided that a layout is given. Numerical performance of the proposed algorithm was compared with
[...] Read more.
An automated algorithm based on the dynamic hydrological and hydraulic simulation modules in Storm Water Management Model (SWMM) was developed to aid the design of storm sewer networks, provided that a layout is given. Numerical performance of the proposed algorithm was compared with the existing design methods with two application cases. The automated computation process of the sewer network design was divided into two stages and solved iteratively, determining pipe diameter and pipe slope, respectively. In the first stage, starting with a set of initial values including pipe diameter, pipe cover depth, and ground elevation at manholes, the iteration was carried out from the downstream to the upstream while the pipe slopes of the network were assumed to be fixed and the diameter of each pipe segment was calculated. In the second stage, pipe diameters calculated from the first stage were fixed and the pipe slopes were calculated successively from the downstream pipe segment to the upstream pipe segment. Every time the diameter or slope of a pipe segment was adjusted, the pipe flow rate, velocity, and flow depth were obtained by running SWMM hydrological and hydraulic simulation modules. The iteration terminated once the combination scheme of pipe diameters and slopes met the design ordinance which requires the pipe flows full under gravity in a design return period. A real urban sewer system in a hilly city and a benchmark sewer network from the literature were tested to validate the proposed automated algorithm, and good performance was shown. The automated design results explicitly show that the proposed storm sewer design approach leads to a quality solution with reduced computational effort. Full article
Figures

Figure 1

Open AccessArticle Spatial and Temporal Variability of Bank Erosion during the Period 1930–2016: Case Study—Kolubara River Basin (Serbia)
Water 2017, 9(10), 748; doi:10.3390/w9100748
Received: 3 July 2017 / Revised: 25 September 2017 / Accepted: 27 September 2017 / Published: 29 September 2017
PDF Full-text (10034 KB) | HTML Full-text | XML Full-text
Abstract
The fluvial process is characterized by an intense meandering riverbed. The aim of this study was to perform a reconstruction of the lateral migration of a 15 km length of an active meandering river during the period 1930–2016. River morphological changes were analyzed
[...] Read more.
The fluvial process is characterized by an intense meandering riverbed. The aim of this study was to perform a reconstruction of the lateral migration of a 15 km length of an active meandering river during the period 1930–2016. River morphological changes were analyzed and quantified from cadastral maps and aerial photographs as well as by geodetic survey and GIS. Hydrological characteristics and extreme hydrological events were evaluated in relation to bank erosion rate. The rate of bank erosion was markedly different from the long-term studied meanders, just like in the short-term period. During the 87 years of observation (from 1930 to 2016), the length of the Kolubara River was enlarged by 3.44 km. The average migration rate of the Kolubara River for monitored meanders in the period 1930–2010 was 1.9 m·year−1, while in the period 2010–2016, the average migration rate was 3.3 m·year−1. The rate of bank erosion was more intensive across the entire short-term period than during the longer period, and the maximum annual rate of bank erosion during the period 2010–2016 varied between 0.3 and 11.5 m. It is very likely that in the period from 2010, frequent discharge variations and rapid change of its extreme values caused more intensive bank erosion. These research results will be valuable for river channel management, engineering (soft and hard engineering), and planning purposes (predicting changes in river channel form) in the Kolubara River Basin. Full article
(This article belongs to the Special Issue Streambank Erosion: Monitoring, Modeling and Management)
Figures

Figure 1

Open AccessArticle Dynamic of Dalinor Lakes in the Inner Mongolian Plateau and Its Driving Factors during 1976–2015
Water 2017, 9(10), 749; doi:10.3390/w9100749
Received: 15 August 2017 / Revised: 13 September 2017 / Accepted: 27 September 2017 / Published: 30 September 2017
PDF Full-text (4361 KB) | HTML Full-text | XML Full-text
Abstract
Climate change and increasing human activities have induced lake expansion or shrinkage, posing a serious threat to the ecological security on the Inner Mongolian Plateau, China. However, the pattern of lake changes and how it responds to climate change and revegetation have rarely
[...] Read more.
Climate change and increasing human activities have induced lake expansion or shrinkage, posing a serious threat to the ecological security on the Inner Mongolian Plateau, China. However, the pattern of lake changes and how it responds to climate change and revegetation have rarely been reported. We investigated the pattern of lake-area changes in the Dalinor National Nature Reserve (DNR) using Landsat imagery during 1976–2015, and examined its relationship with changes in climate and vegetation factors. The total lake-area in the DNR has decreased by 11.6% from 1976 to 2015 with a rate of −0.55 km2 year−1. The largest Dalinor Lake reduced the most (by 32.7 km2) with a rate of −0.79 km2 year−1. The air temperature has increased significantly since 1976, with a rate of 0.03 °C year−1 (p < 0.05), while the precipitation slightly decreased during 1976–2015, with a rate of −0.86 mm year−1. The Normalized Difference Vegetation Index (NDVI) increased by 27.7% from 1976 to 2015, especially after 2001 when vegetation has been promoted greatly as a result of the successful ecological protection and restoration in the Dalinor basin. The decrease in lake-areas for the DNR exhibited a negative correlation with NDVI (r = −0.397, p < 0.05) during 1976–2015. It seems that decreasing precipitation drives the reduction in lake-area, while rising temperature and vegetation greenness accelerated this decreasing trend by increasing evapotranspiration. The continuous lake shrinkage increases the ecological risks to the habitat of birds, causing a challenge to the management in the DNR. Full article
Figures

Figure 1

Open AccessArticle The Agricultural Community as a Social Network in a Collaborative, Multi-Stakeholder Problem-Solving Process
Water 2017, 9(10), 750; doi:10.3390/w9100750
Received: 28 April 2017 / Revised: 21 July 2017 / Accepted: 27 September 2017 / Published: 30 September 2017
PDF Full-text (4085 KB) | HTML Full-text | XML Full-text
Abstract
Collaborative approaches are being promoted as inclusive forums for bringing state and non-state interests together to solve complex environmental problems. Networks have been recognized through previous research as important ways to involve stakeholders in such forums with members participating in knowledge creation and
[...] Read more.
Collaborative approaches are being promoted as inclusive forums for bringing state and non-state interests together to solve complex environmental problems. Networks have been recognized through previous research as important ways to involve stakeholders in such forums with members participating in knowledge creation and sharing as part of deliberative processes. Less well understood is the effectiveness of network creation and promotion by external actors, especially in relation to knowledge creation and sharing. A case study approach was used to evaluate the efforts of a farm organization to organize a provincially-cohesive network of locally-elected agricultural representatives in Ontario, Canada. Network structure and function were evaluated using a combination of participant observation and Social Network Analysis as part of a mixed methods research approach. The results indicate that stakeholder network development can be actively supported, and that knowledge creation and sharing in these networks occurs within a complex structure of local and provincial-scale relationships. Full article
(This article belongs to the Special Issue Source Water Protection: State of the Art and Science)
Figures

Figure 1

Open AccessArticle An Analytical Model of Fickian and Non-Fickian Dispersion in Evolving-Scale Log-Conductivity Distributions
Water 2017, 9(10), 751; doi:10.3390/w9100751
Received: 14 August 2017 / Revised: 25 September 2017 / Accepted: 26 September 2017 / Published: 30 September 2017
PDF Full-text (776 KB) | HTML Full-text | XML Full-text
Abstract
The characteristics of solute transport within log-conductivity fields represented by power-law semi-variograms are investigated by an analytical Lagrangian approach that accounts for the automatic frequency cut-off induced by the initial contaminant plume size. The transport process anomaly is critically controlled by the magnitude
[...] Read more.
The characteristics of solute transport within log-conductivity fields represented by power-law semi-variograms are investigated by an analytical Lagrangian approach that accounts for the automatic frequency cut-off induced by the initial contaminant plume size. The transport process anomaly is critically controlled by the magnitude of the Péclet number. Interestingly enough, unlike the case of fast-decaying correlation functions (i.e., exponential or Gaussian), the presence of intensive transverse diffusion acts as an antagonist mechanism in the process of Fickian regime achievement. On the other hand, for markedly advective conditions and finite initial plume size, even the ergodic longitudinal dispersion coefficient turns out to be asymptotically constant, and the corresponding expected concentration distribution can therefore be obtained by conventional mathematical methods. Full article
Figures

Figure 1

Open AccessArticle Energy Dissipation in Circular Drop Manholes under Different Outflow Conditions
Water 2017, 9(10), 752; doi:10.3390/w9100752
Received: 3 September 2017 / Revised: 21 September 2017 / Accepted: 26 September 2017 / Published: 30 September 2017
PDF Full-text (6421 KB) | HTML Full-text | XML Full-text
Abstract
Circular drop manholes have been an important device for energy dissipation and reduction of flow velocities in urban drainage networks. The energy dissipation in a drop manhole depends on the manhole flow patterns, the outflow regimes in the exit pipe and the downstream
[...] Read more.
Circular drop manholes have been an important device for energy dissipation and reduction of flow velocities in urban drainage networks. The energy dissipation in a drop manhole depends on the manhole flow patterns, the outflow regimes in the exit pipe and the downstream operation conditions, and is closely related to the hydraulic and geometric parameters of the manhole. In the present work, the energy dissipation of a drop manhole with three drop heights was experimentally investigated under free outflow conditions and constrained outflow conditions. The results demonstrate that the local head loss coefficient is solely related to the dimensionless drop parameter for free surface outflow without a downstream backwater effect, whereas it depends on the dimensionless submerge parameter for constrained outflow. Moreover, it is concluded that the energy dissipation is largely promoted when outlet choking occurs. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Estimating River Depth from SWOT-Type Observables Obtained by Satellite Altimetry and Imagery
Water 2017, 9(10), 753; doi:10.3390/w9100753
Received: 14 April 2017 / Revised: 8 September 2017 / Accepted: 26 September 2017 / Published: 30 September 2017
PDF Full-text (2346 KB) | HTML Full-text | XML Full-text
Abstract
The proposed Surface Water and Ocean Topography (SWOT) mission aims to improve spaceborne estimates of river discharge through its measurements of water surface elevation, river width and slope. SWOT, however, will not observe baseflow depth, which limits its value in estimating river discharge
[...] Read more.
The proposed Surface Water and Ocean Topography (SWOT) mission aims to improve spaceborne estimates of river discharge through its measurements of water surface elevation, river width and slope. SWOT, however, will not observe baseflow depth, which limits its value in estimating river discharge especially for those rivers with heterogeneous channel geometry. In this study, we aim to obtain river depths from spaceborne observations together with in situ data of river discharge. We first obtain SWOT-like observables from current satellite techniques. We obtain river water level and slope time series from multi-mission altimetry and effective river width from satellite imagery (MODIS). We then employ a Gauss–Helmert adjustment model to estimate average river depth for 16 defined reaches along the Po River in Italy, for which we use our spaceborne observations in two recognized models for discharge estimation. The average river depth estimates along the Po River are validated against surveyed cross-section information, which shows a generally good agreement in the range of ∼10% relative root mean squared error. Furthermore, we analyzed the sensitivity of error in the estimated river depth to errors of individual parameters. We show that the estimated river depth is less influenced by errors of river width and river discharge, while it is strongly influenced by errors in water level. This result gives a perspective to the SWOT mission to infer river depth by coarse estimates of river width and discharge. Full article
(This article belongs to the Special Issue Advances in Hydro-Meteorological Monitoring)
Figures

Figure 1

Open AccessArticle Spatial and Temporal Variations in Environmental Variables in Relation to Phytoplankton Community Structure in a Eutrophic River-Type Reservoir
Water 2017, 9(10), 754; doi:10.3390/w9100754
Received: 25 July 2017 / Revised: 14 September 2017 / Accepted: 21 September 2017 / Published: 30 September 2017
PDF Full-text (4729 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
This study assesses spatial and temporal variation in environmental variables in relation to phytoplankton community size and composition in a typically eutrophic river reservoir (Hai River, northern China). The aim is to identify environmental parameters governing spatial and temporal differences in phytoplankton density
[...] Read more.
This study assesses spatial and temporal variation in environmental variables in relation to phytoplankton community size and composition in a typically eutrophic river reservoir (Hai River, northern China). The aim is to identify environmental parameters governing spatial and temporal differences in phytoplankton density and composition. Physicochemical parameters, including nutrient concentrations, were determined in monthly surface water samples from 2015. The average concentration of key eutrophication indexes (i.e., total phosphorous (TP: 0.24 ± 0.11 mg·L−1), total nitrogen (TN: 2.96 ± 1.60 mg·L−1), and Chlorophyll a (Chl a: 38.5 ± 11.5 mg·m−3)) substantially exceeded threshold values for eutrophic streams. Moreover, the eutrophication increased significantly downstream along the river reservoir as a consequence of an increasing fraction of agricultural and industrial land-use in the watershed. 103 phytoplankton species were identified, of which Chlorophyta was the dominated phylum (47 species), followed by Bacillariophyta (23 species) and Cyanophyta (18 species). No spatial difference in species distribution (ANOVA, p > 0.05) were found, while the temporal differences in species composition exhibited significant heterogeneity (ANOVA, p < 0.001). Phytoplankton abundance was highest in early summer (June and July), with maximum values increasing from 1.78 × 108 and 2.80 × 108 cells·L−1 in upstream and middle reaches, respectively, to 4.18 × 108 cells·L−1 furthest downstream. Cyanophyta, also known as Cyanobacteria and commonly referred to as blue-green algal, are known to constitute algae bloom in eutrophic systems. Common species are Microcystis marginata, Microcystis flos-aquae, and Oscillatoria sp. This was the dominant phyla during summer months, especially in the middle and lower reaches of the stream reservoir where it accounted for 88.9% of the phytoplankton community. Shannon weaver index (H’) and Pielous’s evenness index (J’) were extremely low (1.91–2.43 for H’ and 0.39–0.45 for J’) in samples collected from the lower part of the stream during the period of algal bloom, indicating an imbalance in the phytoplankton communities. Canonical correspondence analysis (CCA) indicated that water temperature (WT) and possible pH, along with nitrate (NO3-N) and nitrite (NO2-N), were the most important explanatory parameters in regard to phytoplankton composition. This research provides an understanding of the role of physicochemical water quality parameters in governing algal blooms and phytoplankton composition in river reservoirs. Full article
Figures

Figure 1

Open AccessArticle The Importance of Institutional Design for Distributed Local-Level Governance of Groundwater: The Case of California’s Sustainable Groundwater Management Act
Water 2017, 9(10), 755; doi:10.3390/w9100755
Received: 31 July 2017 / Revised: 12 September 2017 / Accepted: 25 September 2017 / Published: 30 September 2017
PDF Full-text (255 KB) | HTML Full-text | XML Full-text
Abstract
In many areas of the world, groundwater resources are increasingly stressed, and unsustainable use has become common. Where existing mechanisms for governing groundwater are ineffective or nonexistent, new ones need to be developed. Local level groundwater governance provides an intriguing alternative to top-down
[...] Read more.
In many areas of the world, groundwater resources are increasingly stressed, and unsustainable use has become common. Where existing mechanisms for governing groundwater are ineffective or nonexistent, new ones need to be developed. Local level groundwater governance provides an intriguing alternative to top-down models, with the promise of enabling management to better match the diversity of physical and social conditions in groundwater basins. One such example is emerging in California, USA, where new state law requires new local agencies to self-organize and act to achieve sustainable groundwater management. In this article, we draw on insights from research on common pool resource management and natural resources governance to develop guidelines for institutional design for local groundwater governance, grounded in California’s developing experience. We offer nine criteria that can be used as principles or standards in the evaluation of institutional design for local level groundwater governance: scale, human capacity, funding, authority, independence, representation, participation, accountability, and transparency. We assert that local governance holds promise as an alternative to centralized governance in some settings but that its success will depend heavily on the details of its implementation. Further, for local implementation to achieve its promise, there remain important complementary roles for centralized governance. California’s developing experience with local level groundwater management in dozens of basins across the state provides a unique opportunity to test and assess the importance and influence of these criteria. Full article
Open AccessArticle Low Impact Development Planning and Adaptation Decision-Making under Climate Change for a Community against Pluvial Flooding
Water 2017, 9(10), 756; doi:10.3390/w9100756
Received: 22 August 2017 / Revised: 12 September 2017 / Accepted: 24 September 2017 / Published: 1 October 2017
PDF Full-text (1919 KB) | HTML Full-text | XML Full-text
Abstract
This study integrates and develops methods, namely low impact development (LID) selection method and an LID spatial planning model, to enable decision-making to minimize pluvial flooding for a community. The objective is to minimize the flood risk under the worst case of the
[...] Read more.
This study integrates and develops methods, namely low impact development (LID) selection method and an LID spatial planning model, to enable decision-making to minimize pluvial flooding for a community. The objective is to minimize the flood risk under the worst case of the design storm within the budget constraints. Design storms in current and future climate scenarios are analyzed as input to the Storm Water Management Model (SWMM). Then, LID practices are selected based on the proposed procedure and a spatial planning model is built to identify the optimal LID layouts using the simulated annealing (SA) algorithm. The lower and upper bounds of the generated rainfall intensities of a five-year 1-h duration design storms for the Hadley Centre Global Environment Model version 2 for the atmosphere and oceans (HadGEM2-AO), the Norwegian Earth System Model (NorESM1-ME), and the CSIRO-Mk3.6.0 Atmosphere-Ocean GCM (CSIRO-Mk3.6.0) during 2021–2040 are derived. The LID selection helps efficiently identify appropriate LID. Results show that nearly no flood occurs under the optimal LID layouts found by the LID spatial planning model. Moreover, it is more optimal to invest in LID in the lower sub-catchments in LID planning when the budget is limited. These methods are generally applicable for a community using LIDs as adaptation measures against pluvial flooding. Full article
Figures

Figure 1

Open AccessArticle Characteristics of Nitrate Removal from Aqueous Solution by Modified Steel Slag
Water 2017, 9(10), 757; doi:10.3390/w9100757
Received: 11 August 2017 / Revised: 27 September 2017 / Accepted: 29 September 2017 / Published: 1 October 2017
PDF Full-text (4763 KB) | HTML Full-text | XML Full-text
Abstract
Steel slag, which makes up a gigantic amount of metallurgical industrial solid waste, was in this experiment successfully synthesized an inexpensive adsorbent used to remove nitrate pollution from aqueous solution. This adsorbent was obtained by mixing steel slag, aluminium hydroxide and deionized water,
[...] Read more.
Steel slag, which makes up a gigantic amount of metallurgical industrial solid waste, was in this experiment successfully synthesized an inexpensive adsorbent used to remove nitrate pollution from aqueous solution. This adsorbent was obtained by mixing steel slag, aluminium hydroxide and deionized water, and aging this at a mass ratio of 3:0.45:2, and then activating it at 800 °C. The physicochemical characteristics of the steel slag before and after modification were investigated to compare the effect of their surface properties on the adsorption behaviour of nitrate. The effects of adsorbent dosage, pH, and contact time on the adsorption process were investigated. The results showed that an increase in specific surface area and the formation of a positive surface of the modified steel slag (MSS) compared with the original steel slag (OSS) could effectively increase the number of the active adsorption sites and nitrate removal ability. The optimum parameters for nitrate removal were as follows: the concentration of nitrate was 20 mg/L, the dosage was 1 g/100 mL, the pH was four, and the reaction time was 180 min. The adsorption capacity of the MSS was approximately 1.9 times that of the OSS. The nitrate adsorption of the MSS was in accordance with the pseudo-second-order model and the Freundlich model, which indicated that the adsorption of nitrate on the MSS was mainly single layer chemical adsorption. The mechanism of nitrate removal mainly included ion exchange, hydrogen bonding, electrostatic interactions and intermolecular interactions. In addition, regeneration experiments indicated that the MSS after regeneration still had the capacity to remove nitrate. Full article
Figures

Figure 1

Open AccessArticle Uncertainty of the Soil–Water Characteristic Curve and Its Effects on Slope Seepage and Stability Analysis under Conditions of Rainfall Using the Markov Chain Monte Carlo Method
Water 2017, 9(10), 758; doi:10.3390/w9100758
Received: 25 August 2017 / Revised: 20 September 2017 / Accepted: 29 September 2017 / Published: 9 October 2017
PDF Full-text (1933 KB) | HTML Full-text | XML Full-text
Abstract
It is important to determine the soil–water characteristic curve (SWCC) for analyzing slope seepage and stability under the conditions of rainfall. However, SWCCs exhibit high uncertainty because of complex influencing factors, which has not been previously considered in slope seepage and stability analysis
[...] Read more.
It is important to determine the soil–water characteristic curve (SWCC) for analyzing slope seepage and stability under the conditions of rainfall. However, SWCCs exhibit high uncertainty because of complex influencing factors, which has not been previously considered in slope seepage and stability analysis under conditions of rainfall. This study aimed to evaluate the uncertainty of the SWCC and its effects on the seepage and stability analysis of an unsaturated soil slope under conditions of rainfall. The SWCC model parameters were treated as random variables. An uncertainty evaluation of the parameters was conducted based on the Bayesian approach and the Markov chain Monte Carlo (MCMC) method. Observed data from granite residual soil were used to test the uncertainty of the SWCC. Then, different confidence intervals for the model parameters of the SWCC were constructed. The slope seepage and stability analysis under conditions of rainfall with the SWCC of different confidence intervals was investigated using finite element software (SEEP/W and SLOPE/W). The results demonstrated that SWCC uncertainty had significant effects on slope seepage and stability. In general, the larger the percentile value, the greater the reduction of negative pore-water pressure in the soil layer and the lower the safety factor of the slope. Uncertainties in the model parameters of the SWCC can lead to obvious errors in predicted pore-water pressure profiles and the estimated safety factor of the slope under conditions of rainfall. Full article
Figures

Figure 1

Open AccessArticle Assessing Factors Driving the Change of Irrigation Water-Use Efficiency in China Based on Geographical Features
Water 2017, 9(10), 759; doi:10.3390/w9100759
Received: 14 August 2017 / Revised: 10 September 2017 / Accepted: 29 September 2017 / Published: 7 October 2017
PDF Full-text (627 KB) | HTML Full-text | XML Full-text
Abstract
Changes in irrigation water-use efficiency are related closely to agricultural development. Clarifying the driving factors of irrigation water-use efficiency change at different agricultural development stages is beneficial for buffering the contradiction between the protection of water resources and massive agricultural water consumption. It
[...] Read more.
Changes in irrigation water-use efficiency are related closely to agricultural development. Clarifying the driving factors of irrigation water-use efficiency change at different agricultural development stages is beneficial for buffering the contradiction between the protection of water resources and massive agricultural water consumption. It also has theoretical and application value when it comes to elucidating the driving characteristics of spatial changes in irrigation water-use efficiency observed among the different provinces of China. This paper analyzes driving factors of irrigation water-use change based on a study of literature and a field survey. It selects 21 indices from five aspects of climatic change, resource endowment, economic situation, technological level, and management mode as the system of driving factors for irrigation water-use change. This article then uses statistical data on economic and social development in the 31 provinces of China in 2009, and applies the principal component analysis (PCA) method to extract the main driving factors affecting irrigation water-use efficiency change. After calculation of factor scores, clustering analysis is conducted on the 31 provinces to explore regional differences among the driving factors of irrigation water-use efficiency change. The results show that these can be attributed to the factors of agricultural economic development, water-saving irrigation technology, water resource endowment, and dissipation. The 31 provinces can be divided into five types: agricultural economy strong driving type; agricultural economy dominant type; industrial economy dominant type; agriculture strong development type; and coordinated driving type. In highly agricultural provinces, mature irrigation district management and water-saving measures influence the efficiency of irrigation water-use, making these strong positive driving factors. In highly industrial provinces, changes in irrigation water-use efficiency are mainly driven by economic development and structural adjustment, making these weak driving factors. Full article
Figures

Figure 1

Open AccessArticle Application of a Hybrid Interpolation Method Based on Support Vector Machine in the Precipitation Spatial Interpolation of Basins
Water 2017, 9(10), 760; doi:10.3390/w9100760
Received: 23 August 2017 / Revised: 24 September 2017 / Accepted: 26 September 2017 / Published: 2 October 2017
PDF Full-text (6341 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, we applied the support vector machine (SVM) to the spatial interpolation of the multi-year average annual precipitation in the Three Gorges Region basin. By combining it with the inverse distance weighting and ordinary kriging method, we constructed the SVM residual
[...] Read more.
In this paper, we applied the support vector machine (SVM) to the spatial interpolation of the multi-year average annual precipitation in the Three Gorges Region basin. By combining it with the inverse distance weighting and ordinary kriging method, we constructed the SVM residual inverse distance weighting, as well as the SVM residual kriging precipitation interpolation model and compared them with the inverse distance weighting, ordinary kriging, linear regression residual inverse distance weighting and linear regression residual kriging interpolation methods. The TRMM 3B43 V7 satellite precipitation information, which is processed by the latest revision algorithm, is used as the auxiliary variable for ground site precipitation interpolation along with latitude and elevation. Our results show that: (1) adding the TRMM 3B43 V7 satellite precipitation data as an auxiliary variable significantly improves the interpolation accuracy of the linear regression equation and SVM model; (2) the support vector machine hybrid interpolation method obtains superior interpolation results compared to the inverse distance weighting method, ordinary kriging method and linear regression hybrid interpolation method; (3) the interpolation accuracy of the SVM hybrid interpolation method depends on the SVM fitting degree, so we should choose a suitable fitting accuracy rather than the highest fitting accuracy; (4) the linear regression equation has a greater degree of dependency on the TRMM data than the SVM. The SVM accepts the TRMM data information while better maintaining its independence, taking into account that the TRMM data linear regression and linear regression hybrid interpolation method are not suitable for TRMM data evaluation. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Removal of Uranium from Contaminated Water by Clay Ceramics in Flow-Through Columns
Water 2017, 9(10), 761; doi:10.3390/w9100761
Received: 8 September 2017 / Revised: 28 September 2017 / Accepted: 29 September 2017 / Published: 2 October 2017
PDF Full-text (3349 KB) | HTML Full-text | XML Full-text
Abstract
Uranium contamination of groundwater increasingly concerns rural residents depending on home wells for their drinking water in communities where uranium is a source of contamination. Established technologies to clean up contaminated aquifers are ineffective in large contaminated areas or are prohibitively expensive. Permeable
[...] Read more.
Uranium contamination of groundwater increasingly concerns rural residents depending on home wells for their drinking water in communities where uranium is a source of contamination. Established technologies to clean up contaminated aquifers are ineffective in large contaminated areas or are prohibitively expensive. Permeable reactive barriers (PRBs) are a low-cost alternative to these methods. In this paper, the applicability of clay ceramic pellets was investigated as permeable reactive barriers (PRBs) material for the treatment of uranium-contaminated groundwater. Flow-through columns were fabricated and used to mimic the flow path of a contaminant plume through the reactive media. Experiment results show that clay ceramic pellets effectively remove uranium from uranium-contaminated water and also can be a cost-efficient technique for remediating uranium contaminated groundwater by a clay pellet barrier. Using clay ceramic pellets is also a practical treatment method for uranium removal from drinking water and can supply potable water for households in the affected areas. Full article
(This article belongs to the Special Issue Desalination and Water Treatment)
Figures

Figure 1

Open AccessArticle Optimal Temporal Resolution of Rainfall for Urban Applications and Uncertainty Propagation
Water 2017, 9(10), 0762; doi:10.3390/w9100762
Received: 29 June 2017 / Revised: 20 September 2017 / Accepted: 22 September 2017 / Published: 4 October 2017
PDF Full-text (5054 KB) | HTML Full-text | XML Full-text
Abstract
The optimal temporal resolution for rainfall applications in urban hydrological models depends on different factors. Accumulations are often used to reduce uncertainty, while a sufficiently fine resolution is needed to capture the variability of the urban hydrological processes. Merging radar and rain gauge
[...] Read more.
The optimal temporal resolution for rainfall applications in urban hydrological models depends on different factors. Accumulations are often used to reduce uncertainty, while a sufficiently fine resolution is needed to capture the variability of the urban hydrological processes. Merging radar and rain gauge rainfall is recognized to improve the estimation accuracy. This work explores the possibility to merge radar and rain gauge rainfall at coarser temporal resolutions to reduce uncertainty, and to downscale the results. A case study in the UK is used to cross-validate the methodology. Rainfall estimates merged and downscaled at different resolutions are compared. As expected, coarser resolutions tend to reduce uncertainty in terms of rainfall estimation. Additionally, an example of urban application in Twenterand, the Netherlands, is presented. The rainfall data from four rain gauge networks are merged with radar composites and used in an InfoWorks model reproducing the urban drainage system of Vroomshoop, a village in Twenterand. Fourteen combinations of accumulation and downscaling resolutions are tested in the InfoWorks model and the optimal is selected comparing the results to water level observations. The uncertainty is propagated in the InfoWorks model with ensembles. The results show that the uncertainty estimated by the ensemble spread is proportional to the rainfall intensity and dependent on the relative position between rainfall cells and measurement points. Full article
(This article belongs to the Special Issue Quantifying Uncertainty in Integrated Catchment Studies)
Figures

Figure 1

Open AccessArticle An Economic Assessment of the Global Potential for Seawater Desalination to 2050
Water 2017, 9(10), 763; doi:10.3390/w9100763
Received: 25 August 2017 / Revised: 2 October 2017 / Accepted: 2 October 2017 / Published: 6 October 2017
PDF Full-text (2236 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Seawater desalination is a promising approach to satisfying water demand in coastal countries suffering from water scarcity. To clarify its potential future global scale, we perform a detailed investigation of the economic feasibility of desalination development for different countries using a feasibility index
[...] Read more.
Seawater desalination is a promising approach to satisfying water demand in coastal countries suffering from water scarcity. To clarify its potential future global scale, we perform a detailed investigation of the economic feasibility of desalination development for different countries using a feasibility index (Fi) that reflects a comparison between the price of water and the cost of production. We consider both past and future time periods. For historical validation, Fi is first evaluated for nine major desalination countries; its variation is in good agreement with the actual historical development of desalination in these countries on both spatial and temporal scales. We then simulate the period of 2015–2050 for a Shared Socioeconomic Pathway (SSP2) and two climate scenarios. Our projected results suggest that desalination will become more feasible for countries undergoing continued development by 2050. The corresponding total global desalination population will increase by 3.2-fold in 2050 compared to the present (from 551.6 × 106 in 2015 to 1768 × 106). The major spread of seawater desalination to more countries and its availability to larger populations is mainly attributed to the diminishing production costs and increasing water prices in these countries under the given socioeconomic/climate scenarios. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Response of Zooplankton to Climate Variability: Droughts Create a Perfect Storm for Cladocerans in Shallow Eutrophic Lakes
Water 2017, 9(10), 764; doi:10.3390/w9100764
Received: 3 August 2017 / Revised: 25 August 2017 / Accepted: 4 October 2017 / Published: 6 October 2017
PDF Full-text (2640 KB) | HTML Full-text | XML Full-text
Abstract
A major attribute of the Earth’s climate that may be affected by global warming is the amplitude of variability in teleconnections. These global-scale processes involve links between oceanic conditions in one locale and weather in another, often distant, locale. An example is the
[...] Read more.
A major attribute of the Earth’s climate that may be affected by global warming is the amplitude of variability in teleconnections. These global-scale processes involve links between oceanic conditions in one locale and weather in another, often distant, locale. An example is the El Niño Southern Oscillation (ENSO), which can affect rainfall and then the properties of lakes in Europe, Africa, North and South America. It affects rainfall, droughts and the depth of lakes in Florida, USA. It is predicted that the amplitude of variation in the ENSO will increase with global warming and, therefore, droughts will become more severe and periods of rain more intense. We investigated possible effects of climate on the zooplankton in shallow subtropical lakes by studying 16 years of monthly data from six shallow eutrophic lakes located north of Orlando, Florida. Results indicate that water depth and lake volume are tightly coupled with rainfall, as expected. During droughts, when lake depth and volume were greatly reduced, there were intensified cyanobacterial blooms, and the zooplankton shifted towards greater relative biomass of copepods compared to cladocerans. The change of zooplankton was likely due to the intensified selective fish predation in the reduced water volume, and/or selective adverse effects of cyanobacteria on cladocerans. The greatly reduced volume might lead to a ‘perfect storm’ of top-down and bottom-up factors that favor copepods over cladocerans. The mechanism needs further study. Regardless, this study documents a direct link between climate variability and zooplankton composition, and suggests how future changes in climate might affect plankton communities. Full article
(This article belongs to the Special Issue Ecological Responses of Lakes to Climate Change)
Figures

Figure 1

Open AccessArticle Surrogate Models for Sub-Region Groundwater Management in the Beijing Plain, China
Water 2017, 9(10), 766; doi:10.3390/w9100766
Received: 26 August 2017 / Revised: 27 September 2017 / Accepted: 3 October 2017 / Published: 9 October 2017
PDF Full-text (8012 KB) | HTML Full-text | XML Full-text
Abstract
Overexploitation of groundwater resources has caused groundwater-related problems all over the world. Effective groundwater governance is a favorable guarantee for its protection and sustainable utilization. Accurate prediction of groundwater level (GWL) or depth to groundwater (GWD) plays an important role in groundwater resource
[...] Read more.
Overexploitation of groundwater resources has caused groundwater-related problems all over the world. Effective groundwater governance is a favorable guarantee for its protection and sustainable utilization. Accurate prediction of groundwater level (GWL) or depth to groundwater (GWD) plays an important role in groundwater resource management. Due to the limitations and complexity of numerical models, this study aims to develop surrogate models that can dually control the GWL (or GWD) and groundwater quantity (GWQ) in each district of the Beijing Plain, China, using the methods of multiple linear regression (MLR) and back propagation artificial neural network (BP-ANN). This study used 180 monthly GWD data records, including the first 168 data records for model development (training) and the remaining 12 data records for model verification. The results indicate that the Nash–Sutcliffe efficiency coefficient (NSE) and correlation coefficient (R) for both the MLR and BP-ANN models are high in most districts and that the MLR models are more appropriate in this study. Fifteen scenarios under different conditions of groundwater use and precipitation are designed to demonstrate the applicability of the developed model in groundwater management. The surrogate models are effective tools that can be used by decision-makers for groundwater management. Full article
Figures

Figure 1

Open AccessArticle An Integrated Modelling System to Predict Hydrological Processes under Climate and Land-Use/Cover Change Scenarios
Water 2017, 9(10), 767; doi:10.3390/w9100767
Received: 30 June 2017 / Revised: 27 September 2017 / Accepted: 29 September 2017 / Published: 9 October 2017
Cited by 1 | PDF Full-text (5605 KB) | HTML Full-text | XML Full-text
Abstract
This study proposes an integrated modeling system consisting of the physically-based MIKE SHE/MIKE 11 model, a cellular automata model, and general circulation models (GCMs) scenarios to investigate the independent and combined effects of future climate and land-use/land-cover (LULC) changes on the hydrology of
[...] Read more.
This study proposes an integrated modeling system consisting of the physically-based MIKE SHE/MIKE 11 model, a cellular automata model, and general circulation models (GCMs) scenarios to investigate the independent and combined effects of future climate and land-use/land-cover (LULC) changes on the hydrology of a river system. The integrated modelling system is applied to the Elbow River watershed in southern Alberta, Canada in conjunction with extreme GCM scenarios and two LULC change scenarios in the 2020s and 2050s. Results reveal that LULC change substantially modifies the river flow regime in the east sub-catchment, where rapid urbanization is occurring. It is also shown that the change in LULC causes an increase in peak flows in both the 2020s and 2050s. The impacts of climate and LULC change on streamflow are positively correlated in winter and spring, which intensifies their influence and leads to a significant rise in streamflow, and, subsequently, increases the vulnerability of the watershed to spring floods. This study highlights the importance of using an integrated modeling approach to investigate both the independent and combined impacts of climate and LULC changes on the future of hydrology to improve our understanding of how watersheds will respond to climate and LULC changes. Full article
Figures

Figure 1

Open AccessArticle Adapting to Variable Water Supply in the Truckee-Carson River System, Western USA
Water 2017, 9(10), 768; doi:10.3390/w9100768
Received: 31 July 2017 / Revised: 18 September 2017 / Accepted: 27 September 2017 / Published: 9 October 2017
PDF Full-text (3861 KB) | HTML Full-text | XML Full-text
Abstract
In snow-fed inland river systems in the western United States, water supply depends upon timing, form, and amount of precipitation. In recent years, this region has experienced unprecedented drought conditions due to decreased snowpack, exacerbated by exceptionally warmer winter temperatures averaging 3–4 °C
[...] Read more.
In snow-fed inland river systems in the western United States, water supply depends upon timing, form, and amount of precipitation. In recent years, this region has experienced unprecedented drought conditions due to decreased snowpack, exacerbated by exceptionally warmer winter temperatures averaging 3–4 °C above normal. In the snow-fed Truckee-Carson River System, two sets of interviews were conducted as part of a larger collaborative modeling case study with local water managers to examine local adaptation to current drought conditions. A comparative analysis of these primary qualitative data, collected during the fourth and fifth consecutive years of continued warmer drought conditions, identifies shifts in adaptation strategies and emergent adaptation barriers. That is, under continuous exposure to climate stressors, managers shifted their adaptation focus from short-term efforts to manage water demand toward long-term efforts to enhance water supply. Managers described the need to: improve forecasts and scientific assessments of snowmelt timing, groundwater levels, and soil moisture content; increase flexibility of prior appropriation water allocation rules based on historical snowpack and streamflow timing; and foster collaboration and communication among water managers across the river system. While water scarcity and insufficient water delivery infrastructure remain significant impediments in this arid region, climate uncertainty emerged as a barrier surrounding adaptation to variable water supply. Existing prior appropriation based water institutions were also described as an adaptation barrier, meriting objective evaluation to assess how to best modify these historical institutions to support dynamic adaptation to climate-induced water supply variability. This study contributes to a growing body of research that assesses drought adaptation in snow-fed inland river systems, and contributes a unique report concerning how adaptation strategies and barriers encountered by local water managers change over time under continuous exposure to climate stressors. These locally identified adaptation strategies forward a larger collaborative modeling case study by informing alternative water management scenarios simulated through a suite of hydrologic and operations models tailored to this river system. Full article
(This article belongs to the Special Issue Sustainable Water Management within Inland River Watershed)
Figures

Figure 1

Open AccessArticle Application of Hydrological Model PRMS to Simulate Daily Rainfall Runoff in Zamask-Yingluoxia Subbasin of the Heihe River Basin
Water 2017, 9(10), 769; doi:10.3390/w9100769
Received: 2 July 2017 / Revised: 19 September 2017 / Accepted: 21 September 2017 / Published: 9 October 2017
PDF Full-text (2235 KB) | HTML Full-text | XML Full-text
Abstract
The Precipitation-Runoff Modeling System (PRMS) has been applied to simulate rainfall runoff in Zamask-Yingluoxia subbasin of the Heihe River Basin in this study. By using observed data in the subbasin, the model has been calibrated by comparing model simulations of daily stream flow
[...] Read more.
The Precipitation-Runoff Modeling System (PRMS) has been applied to simulate rainfall runoff in Zamask-Yingluoxia subbasin of the Heihe River Basin in this study. By using observed data in the subbasin, the model has been calibrated by comparing model simulations of daily stream flow to observed data at Yinglouxia station for the period of summer in 2004. Then model verification was conducted by keeping the same model parameters for the simulation of the period from 1 January 2003 to 31 December 2006. Results from model verification indicate that the model is able to provide good accuracy of simulations of daily rainfall runoff and river flow at Yinglouxia station, with a Nash-Sutcliffe Efficiency coefficient of 0.90 and the root-mean-square error of 15.7 m3/s. The error of maximum peak flow is 6.9 m3/s (1.8%) and the error of mean flow is 1.4 m3/s (2.5%). Comparing to previous studies, results indicate the improvement of model accuracy in simulations of daily rainfall runoff. The calibrated and verified hydrological model can be used to support flood hazard mitigations and water resource management in the Zamask-Yingluoxia subbasin. Full article
(This article belongs to the Special Issue Sustainable Water Management within Inland River Watershed)
Figures

Figure 1

Open AccessArticle Sunshine Duration Variability in Haihe River Basin, China, during 1966–2015
Water 2017, 9(10), 770; doi:10.3390/w9100770
Received: 17 July 2017 / Revised: 1 October 2017 / Accepted: 1 October 2017 / Published: 9 October 2017
PDF Full-text (5396 KB) | HTML Full-text | XML Full-text
Abstract
Sunshine can have a profound impact on the systematic change in climate elements, such as temperature and wind speed, and in turn affects many aspects of the human society. In recent years, there has been a substantial interest in the variation of sunshine
[...] Read more.
Sunshine can have a profound impact on the systematic change in climate elements, such as temperature and wind speed, and in turn affects many aspects of the human society. In recent years, there has been a substantial interest in the variation of sunshine duration due to the dramatic global climate change. Hence, there is a need to better understand the variation of sunshine duration in order to cope with climate change. This study aimed to analyze the variation of sunshine duration in Haihe River basin, China, and its relationship with temperature, wind speed and low-level cloudiness. The annual, seasonal and monthly changes of sunshine duration were analyzed based on the data collected from 33 meteorological stations over the Haihe River basin during 1966–2015. It is evident that the annual, seasonal and monthly sunshine duration shows a decreasing trend over time. In addition, the annual sunshine duration is lower with a higher climate tendency rate in the southern and eastern coastal regions than that in the northwestern regions. It is negatively correlated with temperature (r = −0.50) and low-level cloudiness (r = −0.29), but positively with wind speed (r = 0.61). Wind speed may be one of the important causes of the decrease of sunshine duration in the Haihe River basin during 1966–2015. These changes may have significant implications for the hydrological cycle in the area. Full article
Figures

Figure 1

Open AccessArticle Generalized Storage–Yield–Reliability Relationships for Analysing Shopping Centre Rainwater Harvesting Systems
Water 2017, 9(10), 771; doi:10.3390/w9100771
Received: 11 August 2017 / Revised: 27 September 2017 / Accepted: 30 September 2017 / Published: 10 October 2017
PDF Full-text (10476 KB) | HTML Full-text | XML Full-text
Abstract
The objective of this study was to develop guidelines for analysing rainwater harvesting (RWH) systems of shopping centres in South Africa. A model consisting of three dimensionless relationships relating rainwater supply and demand to storage capacity, yield and reliability was formulated. Data from
[...] Read more.
The objective of this study was to develop guidelines for analysing rainwater harvesting (RWH) systems of shopping centres in South Africa. A model consisting of three dimensionless relationships relating rainwater supply and demand to storage capacity, yield and reliability was formulated. Data from daily simulation of potential RWH systems of 19 shopping were used to obtain the relationships. The simulations revealed within-year storage behaviour with considerable variation of annual yield. By applying the Weibull plotting position formula, yield–reliability relationships were derived. The aim to maximize yield and reliability whilst minimizing storage identified Pareto-optimal combinations of the three variables and these combinations were used to develop two dimensionless relationships. An additional relationship based on the dependence of the slope of the yield–reliability plots on yield was formulated to enable analysis of hydrologically non-optimal systems. Verification tests using four RWH systems obtained results that matched those from simulation and the model could therefore be applied for RWH feasibility analysis and preliminary design. This study highlights the need to incorporate inter-annual variability in RWH analysis and shows how reliability can be used to quantify this. This study further demonstrates how reliability can be fully integrated into regression relationships for generalized RWH analysis. Full article
Figures

Figure 1

Open AccessArticle Three-Dimensional Modeling of Wind- and Temperature-Induced Flows in the Icó-Mandantes Bay, Itaparica Reservoir, NE Brazil
Water 2017, 9(10), 772; doi:10.3390/w9100772
Received: 8 August 2017 / Revised: 27 September 2017 / Accepted: 30 September 2017 / Published: 10 October 2017
PDF Full-text (13165 KB) | HTML Full-text | XML Full-text
Abstract
The Icó-Mandantes Bay is one of the major branches of the Itaparica Reservoir (Sub-Middle São Francisco River, Northeast Brazil) and is the focus of this study. Besides the harmful algae blooms (HAB) and a severe prolonged drought, the bay has a strategic importance—e.g.,
[...] Read more.
The Icó-Mandantes Bay is one of the major branches of the Itaparica Reservoir (Sub-Middle São Francisco River, Northeast Brazil) and is the focus of this study. Besides the harmful algae blooms (HAB) and a severe prolonged drought, the bay has a strategic importance—e.g., the eastern channel of the newly built water diversion will withdraw water from it (drinking water). This article presents the implementation of a three-dimensional (3D) numerical model—pioneering for the region—using TELEMAC-3D. The aim was to investigate the 3D flows induced by moderate or extreme winds as well as by heating of the water surface. The findings showed that a windstorm increased the flow velocities (at least one order of magnitude, i.e., up to 10−1–10−2 m/s) without altering significantly the circulation patterns; this occurred substantially for the heating scenario, which had, in contrast, a lower effect on velocities. In terms of the bay’s management, the main implications are: (1) the withdrawals for drinking water and irrigation agriculture should stop working during windstorms and at least three days afterwards; (2) a heating of the water surface would likely increase the risk of development of HAB in the shallow areas, so that further assessments with a water quality module are needed to support advanced remediation measures; (3) the 3D model proves to be a necessary tool to identify high risk contamination areas e.g., for installation of new aquaculture systems. Full article
Figures

Figure 1

Open AccessArticle Leakage Detection and Estimation Algorithm for Loss Reduction in Water Piping Networks
Water 2017, 9(10), 773; doi:10.3390/w9100773
Received: 10 August 2017 / Revised: 27 September 2017 / Accepted: 29 September 2017 / Published: 11 October 2017
PDF Full-text (1293 KB) | HTML Full-text | XML Full-text
Abstract
Water loss through leaking pipes constitutes a major challenge to the operational service of water utilities. In recent years, increasing concern about the financial loss and environmental pollution caused by leaking pipes has been driving the development of efficient algorithms for detecting leakage
[...] Read more.
Water loss through leaking pipes constitutes a major challenge to the operational service of water utilities. In recent years, increasing concern about the financial loss and environmental pollution caused by leaking pipes has been driving the development of efficient algorithms for detecting leakage in water piping networks. Water distribution networks (WDNs) are disperse in nature with numerous number of nodes and branches. Consequently, identifying the segment(s) of the network and the exact leaking pipelines connected to this segment(s) where higher background leakage outflow occurs is a challenging task. Background leakage concerns the outflow from small cracks or deteriorated joints. In addition, because they are diffuse flow, they are not characterised by quick pressure drop and are not detectable by measuring instruments. Consequently, they go unreported for a long period of time posing a threat to water loss volume. Most of the existing research focuses on the detection and localisation of burst type leakages which are characterised by a sudden pressure drop. In this work, an algorithm for detecting and estimating background leakage in water distribution networks is presented. The algorithm integrates a leakage model into a classical WDN hydraulic model for solving the network leakage flows. The applicability of the developed algorithm is demonstrated on two different water networks. The results of the tested networks are discussed and the solutions obtained show the benefits of the proposed algorithm. A noteworthy evidence is that the algorithm permits the detection of critical segments or pipes of the network experiencing higher leakage outflow and indicates the probable pipes of the network where pressure control can be performed. However, the possible position of pressure control elements along such critical pipes will be addressed in future work. Full article
Figures

Figure 1

Open AccessArticle Long-Term Managed Aquifer Recharge in a Saline-Water Aquifer as a Critical Component of an Integrated Water Scheme in Southwestern Florida, USA
Water 2017, 9(10), 774; doi:10.3390/w9100774
Received: 25 August 2017 / Revised: 25 September 2017 / Accepted: 3 October 2017 / Published: 11 October 2017
PDF Full-text (4890 KB) | HTML Full-text | XML Full-text
Abstract
Managed Aquifer Recharge (MAR) systems can be used within the context of integrated water management to create solutions to multiple objectives. Southwestern Florida is faced with severe environmental problems associated with the wet season discharge of excessive quantities of surface water containing high
[...] Read more.
Managed Aquifer Recharge (MAR) systems can be used within the context of integrated water management to create solutions to multiple objectives. Southwestern Florida is faced with severe environmental problems associated with the wet season discharge of excessive quantities of surface water containing high concentrations of nutrients into the Caloosahatchee River Estuary and a future water supply shortage. A 150,000 m3/day MAR system is proposed as an economic solution to solve part of the environmental and water supply issues. Groundwater modeling has demonstrated that the injection of about 150,000 m3/day into the Avon Park High Permeable Zone will result in the creation of a 1000 m wide plume of fresh and brackish-water (due to mixing) extending across the water short area over a 10-year period. The operational cost of the MAR injection system would be less than $0.106/m3 and the environmental benefits would alone more than cover this cost in the long term. In addition, the future unit water supply cost to the consumer would be reduced from $1 to $1.25/m3 to $0.45 to $0.65/m3. Full article
(This article belongs to the Special Issue Aquifer Storage and Recovery: Theory, Design, and Operation)
Figures

Figure 1

Open AccessArticle Forecasting and Providing Warnings of Flash Floods for Ungauged Mountainous Areas Based on a Distributed Hydrological Model
Water 2017, 9(10), 776; doi:10.3390/w9100776
Received: 18 August 2017 / Revised: 28 September 2017 / Accepted: 28 September 2017 / Published: 11 October 2017
Cited by 1 | PDF Full-text (3866 KB) | HTML Full-text | XML Full-text
Abstract
Flash floods occur in mountainous catchments with short response times, which are among the most devastating natural hazards in China. This paper intends to forecast and provide warnings of flash floods timely and precisely using the flash flood warning system, which is established
[...] Read more.
Flash floods occur in mountainous catchments with short response times, which are among the most devastating natural hazards in China. This paper intends to forecast and provide warnings of flash floods timely and precisely using the flash flood warning system, which is established by a new distributed hydrological model (the China flash flood hydrological model, CNFF-HM). Two ungauged mountainous regions, Shunchang and Zherong, are chosen as the study areas. The CNFF-HM is calibrated in five well-monitored catchments. The parameters for the ungauged regions are estimated by regionalization. River water stage data and reservoir water stage data from Shunchang, and reservoir water stage data from Zherong are used to validate the model. The model performs well and the average Nash–Sutcliffe efficiency (NSE) is above 0.8 for the five catchments. The validation shows the difference in the timing of flood peaks using the two types of water stage data is less than 1 h. The rising and declining trends of the floods correspond to the observed trends over the entire validation process. Furthermore, the flash flood warning system was effectively applied in flash flood event on 28 September 2016 in Zherong. Thus, the CNFF-HM with regionalization is effective in forecasting flash floods for ungauged mountainous regions. Full article
Figures

Figure 1

Open AccessArticle Integrated Application of Remote Sensing, GIS and Hydrological Modeling to Estimate the Potential Impact Area of Earthquake-Induced Dammed Lakes
Water 2017, 9(10), 777; doi:10.3390/w9100777
Received: 7 September 2017 / Revised: 30 September 2017 / Accepted: 9 October 2017 / Published: 12 October 2017
PDF Full-text (36496 KB) | HTML Full-text | XML Full-text
Abstract
Dammed lakes are an important secondary hazard caused by earthquakes. They can induce further damage to nearby humans. Current hydrology calculation research on dammed lakes usually lacks spatial expressive ability and cannot accurately conduct impact assessment without the support of remote sensing, which
[...] Read more.
Dammed lakes are an important secondary hazard caused by earthquakes. They can induce further damage to nearby humans. Current hydrology calculation research on dammed lakes usually lacks spatial expressive ability and cannot accurately conduct impact assessment without the support of remote sensing, which obtains important characteristic information of dammed lakes. The current study aims to address the issues of the potential impact area estimate of earthquake-induced dammed lakes by combining remote sensing (RS), a geographic information system (GIS), and hydrological modeling. The Tangjiashan dammed lake induced by the Wenchuan earthquake was selected as the case for study. The elevation-versus-reservoir capacity curve was first calculated using the seed-growing algorithm based on digital elevation model (DEM) data. The simulated annealing algorithm was applied to train the hydrological modeling parameters according to the historical hydrologic data. Then, the downstream water elevation variational process under different collapse capacity conditions was performed based on the obtained parameters. Finally, the downstream potential impact area was estimated by the highest water elevation values at different hydrologic sections. Results show that a flood with a collapse elevation of at least 680 m will impact the entire downstream region of Beichuan town. We conclude that spatial information technology combined with hydrological modeling can accurately predict and demonstrate the potential impact area with limited data resources. This paper provides a better guide for future immediate responses to dammed lake hazard mitigation. Full article
Figures

Figure 1

Open AccessArticle A Keystone Methylobacterium Strain in Biofilm Formation in Drinking Water
Water 2017, 9(10), 778; doi:10.3390/w9100778
Received: 31 August 2017 / Revised: 17 September 2017 / Accepted: 9 October 2017 / Published: 12 October 2017
PDF Full-text (3130 KB) | HTML Full-text | XML Full-text
Abstract
The structure of biofilms in drinking water systems is influenced by the interplay between biological and physical processes. Bacterial aggregates in bulk fluid are important in seeding biofilm formation on surfaces. In simple pure and co-cultures, certain bacteria, including Methylobacterium, are implicated
[...] Read more.
The structure of biofilms in drinking water systems is influenced by the interplay between biological and physical processes. Bacterial aggregates in bulk fluid are important in seeding biofilm formation on surfaces. In simple pure and co-cultures, certain bacteria, including Methylobacterium, are implicated in the formation of aggregates. However, it is unclear whether they help to form aggregates in complex mixed bacterial communities. Furthermore, different flow regimes could affect the formation and destination of aggregates. In this study, real drinking water mixed microbial communities were inoculated with the Methylobacterium strain DSM 18358. The propensity of Methylobacterium to promote aggregation was monitored under both stagnant and flow conditions. Under stagnant conditions, Methylobacterium enhanced bacterial aggregation even when it was inoculated in drinking water at 1% relative abundance. Laminar and turbulent flows were developed in a rotating annular reactor. Methylobacterium was found to promote a higher degree of aggregation in turbulent than laminar flow. Finally, fluorescence in situ hybridisation images revealed that Methylobacterium aggregates had distinct spatial structures under the different flow conditions. Overall, Methylobacterium was found to be a key strain in the formation of aggregates in bulk water and subsequently in the formation of biofilms on surfaces. Full article
(This article belongs to the Special Issue Biofilm Formation on Membranes in Water and Wastewater Treatment)
Figures

Figure 1

Open AccessArticle Study on Mercury Distribution and Speciation in Urban Road Runoff in Nanjing City, China
Water 2017, 9(10), 779; doi:10.3390/w9100779
Received: 7 September 2017 / Revised: 22 September 2017 / Accepted: 2 October 2017 / Published: 12 October 2017
PDF Full-text (1261 KB) | HTML Full-text | XML Full-text
Abstract
The current study was aimed to investigate the mercury pollution in urban road runoff. A total of 34 rainfall events were monitored on 5 independent road catchments from 2015 to 2016 in Nanjing city, China. Events mean concentrations of mercury and the impact
[...] Read more.
The current study was aimed to investigate the mercury pollution in urban road runoff. A total of 34 rainfall events were monitored on 5 independent road catchments from 2015 to 2016 in Nanjing city, China. Events mean concentrations of mercury and the impact factors of mercury pollution in urban road runoff were also carried out in the current study. Results revealed that the concentration of various mercury species was very high. Total mercury, dissolved mercury and particulate mercury were found to be in the range of 0.173–8.254 μg/L, 0.069–6.823 μg/L, and 0.086–2.485 μg/L, respectively. The order of total mercury concentration among the five catchments was as follows: Longpan road > Xinjiekou > Jiulonghu > Zhujiang road > Maqun area. Results revealed the existence of different dominant species of mercury in different urban areas. Particularly, mercury in urban road runoff mainly existed in particulate form in Maqun area, and the concentrations of inactive mercury (0.250–2.821 μg/L) were far more than that of volatile mercury (0.023–0.215 μg/L) and active mercury (0.026–0.359 μg/L). The order of impact factors of rainfall characteristics on Hg pollution in runoff was dry periods > runoff time > duration of rainfall > storm intensity > rainfall. Analysis based on the first flush effect showed that the first flush phenomenon of mercury was not significant. Full article
(This article belongs to the Special Issue Sponge Cities: Emerging Approaches, Challenges and Opportunities)
Figures

Figure 1

Open AccessArticle Using the HSPF and SWMM Models in a High Pervious Watershed and Estimating Their Parameter Sensitivity
Water 2017, 9(10), 780; doi:10.3390/w9100780
Received: 4 August 2017 / Revised: 24 September 2017 / Accepted: 3 October 2017 / Published: 12 October 2017
PDF Full-text (3912 KB) | HTML Full-text | XML Full-text
Abstract
Models are necessary tools for watershed management. However, applying watershed models is time consuming and requires technical knowledge, including model selection and validation. The objective of this study is to assess two commonly used watershed models and their parameter sensitivity to reduce model
[...] Read more.
Models are necessary tools for watershed management. However, applying watershed models is time consuming and requires technical knowledge, including model selection and validation. The objective of this study is to assess two commonly used watershed models and their parameter sensitivity to reduce model loadings and to gain a better understanding of the model performances. The Hydrological Simulation Program-Fortran (HSPF) model and Storm Water Management Model (SWMM) were applied to a mostly forested Taiwanese reservoir watershed with pollution from tea plantations. Statistical analysis showed that both models are suitable for the studied watershed, but the performances of the flow and water quality simulations are different. The mean flow simulated by SWMM was lower than the experimental observations. The HSPF model performed better, possibly because the soil in the study area is highly permeable and the HSPF model has more precise soil layer calculations. SWMM may underestimate the total phosphorous (TP) and suspended solid (SS) loads following small storm events in highly permeable watersheds. The Latin Hypercube-One factor At a Time (LH-OAT) method was used to determine the parameter sensitivity of the HSPF model and SWMM. In both of the models, the parameters related to infiltration and soil characteristics strongly affected the flow simulation, except when using the Horton infiltration method in the SWMM. Manning’s roughness coefficient for pervious areas was more sensitive in SWMM than in the HSPF model because SWMM has fewer parameters. Full article
Figures

Figure 1

Open AccessArticle Comparative Analysis of ANN and SVM Models Combined with Wavelet Preprocess for Groundwater Depth Prediction
Water 2017, 9(10), 781; doi:10.3390/w9100781
Received: 25 August 2017 / Revised: 20 September 2017 / Accepted: 29 September 2017 / Published: 12 October 2017
PDF Full-text (7016 KB) | HTML Full-text | XML Full-text
Abstract
Reliable prediction of groundwater depth fluctuations has been an important component in sustainable water resources management. In this study, a data-driven prediction model combining discrete wavelet transform (DWT) preprocess and support vector machine (SVM) was proposed for groundwater depth forecasting. Regular artificial neural
[...] Read more.
Reliable prediction of groundwater depth fluctuations has been an important component in sustainable water resources management. In this study, a data-driven prediction model combining discrete wavelet transform (DWT) preprocess and support vector machine (SVM) was proposed for groundwater depth forecasting. Regular artificial neural networks (ANN), regular SVM, and wavelet preprocessed artificial neural networks (WANN) models were also developed for comparison. These methods were applied to the monthly groundwater depth records over a period of 37 years from ten wells in the Mengcheng County, China. Relative absolute error (RAE), Pearson correlation coefficient (r), root mean square error (RMSE), and Nash-Sutcliffe efficiency (NSE) were adopted for model evaluation. The results indicate that wavelet preprocess extremely improved the training and test performance of ANN and SVM models. The WSVM model provided the most precise and reliable groundwater depth prediction compared with ANN, SVM, and WSVM models. The criterion of RAE, r, RMSE, and NSE values for proposed WSVM model are 0.20, 0.97, 0.18 and 0.94, respectively. Comprehensive comparisons and discussion revealed that wavelet preprocess extremely improves the prediction precision and reliability for both SVM and ANN models. The prediction result of SVM model is superior to ANN model in generalization ability and precision. Nevertheless, the performance of WANN is superior to SVM model, which further validates the power of data preprocess in data-driven prediction models. Finally, the optimal model, WSVM, is discussed by comparing its subseries performances as well as model performance stability, revealing the efficiency and universality of WSVM model in data driven prediction field. Full article
(This article belongs to the Special Issue Groundwater Monitoring and Remediation)
Figures

Figure 1

Open AccessArticle Streamflow and Sediment Yield Prediction for Watershed Prioritization in the Upper Blue Nile River Basin, Ethiopia
Water 2017, 9(10), 782; doi:10.3390/w9100782
Received: 6 August 2017 / Revised: 25 September 2017 / Accepted: 2 October 2017 / Published: 12 October 2017
PDF Full-text (7596 KB) | HTML Full-text | XML Full-text
Abstract
Inappropriate use of land and poor ecosystem management have accelerated land degradation and reduced the storage capacity of reservoirs. To mitigate the effect of the increased sediment yield, it is important to identify erosion-prone areas in a 287 km2 catchment in Ethiopia. The
[...] Read more.
Inappropriate use of land and poor ecosystem management have accelerated land degradation and reduced the storage capacity of reservoirs. To mitigate the effect of the increased sediment yield, it is important to identify erosion-prone areas in a 287 km2 catchment in Ethiopia. The objectives of this study were to: (1) assess the spatial variability of sediment yield; (2) quantify the amount of sediment delivered into the reservoir; and (3) prioritize sub-catchments for watershed management using the Soil and Water Assessment Tool (SWAT). The SWAT model was calibrated and validated using SUFI-2, GLUE, ParaSol, and PSO SWAT-CUP optimization algorithms. For most of the SWAT-CUP simulations, the observed and simulated river discharge were not significantly different at the 95% level of confidence (95PPU), and sources of uncertainties were captured by bracketing more than 70% of the observed data. This catchment prioritization study indicated that more than 85% of the sediment was sourced from lowland areas (slope range: 0–8%) and the variation in sediment yield was more sensitive to the land use and soil type prevailing in the area regardless of the terrain slope. Contrary to the perception of the upland as an important source of sediment, the lowland in fact was the most important source of sediment and should be the focus area for improved land management practice to reduce sediment delivery into storage reservoirs. The research also showed that lowland erosion-prone areas are typified by extensive agriculture, which causes significant modification of the landscape. Tillage practice changes the infiltration and runoff characteristics of the land surface and interaction of shallow groundwater table and saturation excess runoff, which in turn affects the delivery of water and sediment to the reservoir and catchment evapotranspiration. Full article
Figures

Open AccessArticle Long-Term Downstream Effects of a Dam on a Lowland River Flow Regime: Case Study of the Upper Narew
Water 2017, 9(10), 783; doi:10.3390/w9100783
Received: 7 September 2017 / Revised: 9 October 2017 / Accepted: 10 October 2017 / Published: 12 October 2017
PDF Full-text (5396 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Most European riverine ecosystems suffer from the negative influence of impoundments on flow regime. Downstream effects of dams lead to a number of environmental and socioeconomic risks and, therefore, should be thoroughly examined in specific contexts. Our study aims to quantify the downstream
[...] Read more.
Most European riverine ecosystems suffer from the negative influence of impoundments on flow regime. Downstream effects of dams lead to a number of environmental and socioeconomic risks and, therefore, should be thoroughly examined in specific contexts. Our study aims to quantify the downstream effects of the Siemianówka Reservoir (Upper Narew, Poland), using statistical analysis of key elements of the river’s flow regime, such as the flow duration and recurrence of floods and droughts. In a comparative study on control catchments not influenced by impoundments (the Supraśl and Narewka Rivers), we revealed the following downstream effects of the analyzed dam: significant shortening of spring floods, reduction of the duration and depth of summer droughts, decrease of the maximum discharge, and homogenization of the discharge hydrographs. Although we determined a significant decrease in the duration of summer floods in the “before” and “after” dam function periods, we showed that this issue is regional, climate-related, and replicated in control catchments, rather than an evident downstream effect of the dam. We conclude that significant hydrological downstream effects of the Siemianówka dam–reservoir system could have been the main driver inducing the deterioration of the anastomosing stretch of the Narew River downstream of the dam. Full article
(This article belongs to the Special Issue Adaptive Catchment Management and Reservoir Operation)
Figures

Figure 1

Open AccessArticle Stormwater Runoff Characteristics and Effective Management of Nonpoint Source Pollutants from a Highland Agricultural Region in the Lake Soyang Watershed
Water 2017, 9(10), 784; doi:10.3390/w9100784
Received: 21 August 2017 / Revised: 29 September 2017 / Accepted: 3 October 2017 / Published: 12 October 2017
PDF Full-text (9525 KB) | HTML Full-text | XML Full-text
Abstract
The dense highland field area in the upstream region of the Lake Soyang watershed is subject to excessive soil erosion during the wet season. In this study, stormwater runoff from the Lake Soyang watershed was monitored during four rainfall events at 10 locations
[...] Read more.
The dense highland field area in the upstream region of the Lake Soyang watershed is subject to excessive soil erosion during the wet season. In this study, stormwater runoff from the Lake Soyang watershed was monitored during four rainfall events at 10 locations throughout 2016. The maximum SS concentration at Naedongcheon, which is located in the upper part of the Soyang River, reached 4598 mg/L. The event mean concentration (EMC) of SS loads in Naedongcheon ranged from 82.2 mg/L to 926.3 mg/L. We found that, although the first flush events were usually concentrated in highly paved urban areas, a first flush occurred in the agricultural area of the dense highland field region. The first flush phenomenon was identified by a dimensionless cumulative runoff mass and volume curve (M(V) curve), and the intensity of the first flush was analyzed by the coefficient of the nonlinear regression model and the FF30 and FF25 values (the fraction of pollution load transported by the first 30% and 25% of runoff, respectively). Nonlinear regression models using the power function were applied to fit the M(V) curve, the FF30 values were inversely proportional to the coefficient a of the regression model. A long-term seasonal trend decomposition for monthly turbidity and precipitation was performed for the Lake Soyang. Long-term turbidity trend was approximately coincident with the trend in long-term precipitation. In addition, the present status of the best management practices (BMPs) in the upper part of the Soyang River basin was investigated, and a survey of the management and operation of the BMPs was conducted for selected farmers. Full article
(This article belongs to the Special Issue Water Quality Monitoring and Modeling in Lakes)
Figures

Figure 1

Open AccessArticle How to Improve Water Usage Efficiency? Characterization of Family Farms in A Semi-Arid Area
Water 2017, 9(10), 785; doi:10.3390/w9100785
Received: 8 September 2017 / Revised: 28 September 2017 / Accepted: 9 October 2017 / Published: 13 October 2017
PDF Full-text (1863 KB) | HTML Full-text | XML Full-text
Abstract
Water scarcity in Spain is partly due to poor management of this resource in the agricultural sector. The main aim of this study is to present the major factors related to water usage efficiency in farming. It focuses on the Almería coast, southeast
[...] Read more.
Water scarcity in Spain is partly due to poor management of this resource in the agricultural sector. The main aim of this study is to present the major factors related to water usage efficiency in farming. It focuses on the Almería coast, southeast Spain, which is one of the most arid areas of the country, and in particular, on family farms as the main direct managers of water use in this zone. Many of these farms are among the most water efficient in Spanish agriculture but this efficiency is not generalized throughout the sector. This work conducts a comprehensive assessment of water performance in this area, using on-farm water-use, structural, socio-economic, and environmental information. Two statistical techniques are used: descriptive analysis and cluster analysis. Thus, two groups are identified: farms that are less and farms that are more efficient regarding water usage. By analyzing both the common characteristics within each group and the differences between the groups with a one-way ANOVA analysis, several conclusions can be reached. The main differences between the two clusters center on the extent to which innovation and new technologies are used in irrigation. The most water efficient farms are characterized by more educated farmers, a greater degree of innovation, new irrigation technology, and an awareness of water issues and environmental sustainability. The findings of this study can be extended to farms in similar arid and semi-arid areas and contribute to fostering appropriate policies to improve the efficiency of water usage in the agricultural sector. Full article
Figures

Figure 1

Open AccessArticle Removal of Nitrogen and COD from Reclaimed Water during Long-Term Simulated Soil Aquifer Treatment System under Different Hydraulic Conditions
Water 2017, 9(10), 786; doi:10.3390/w9100786
Received: 3 September 2017 / Revised: 30 September 2017 / Accepted: 10 October 2017 / Published: 16 October 2017
PDF Full-text (3353 KB) | HTML Full-text | XML Full-text
Abstract
Reclaimed water is an important supplementary source for fresh water. Purification is necessary prior to utilization in order to minimize the pollution and human-health risk. A three-year experiment was carried out to study the removal of nitrogen and organics through a simulated soil
[...] Read more.
Reclaimed water is an important supplementary source for fresh water. Purification is necessary prior to utilization in order to minimize the pollution and human-health risk. A three-year experiment was carried out to study the removal of nitrogen and organics through a simulated soil aquifer treatment (SAT) system under continuous wetting and wetting/drying conditions. The removal performance of nitrogen and chemical oxygen demand (COD) was improved in the wetting/drying column. The average removal efficiencies of the three years were 51% and 78% for the NO3–N, 41% and 51% for the NH4–N, and 40% and 50% for the COD in the continuous wetting and wetting/drying columns. Nitrogen and COD removal mainly took place within the top 20 cm of the columns, which was highly correlated with the distribution of microorganisms. The amount of microorganisms was also positively correlated with the content of organic matter and dissolved oxygen (DO) in both soil columns. NO3–N can be removed effectively via aerobic denitrifying bacteria as the DO concentration was 3–6 mg/L. DO and NO3–N were simultaneously reduced as the electron acceptors for COD degradation, and DO only accounted for 40% of total electron acceptor in COD degradation for the continuous wetting column. Nitrogen and COD can be effectively and steadily removed from reclaimed water during the long-term operation of a SAT system. Full article
Figures

Figure 1

Open AccessArticle Optimization of Multiple Seepage Piping Parameters to Maximize the Critical Hydraulic Gradient in Bimsoils
Water 2017, 9(10), 787; doi:10.3390/w9100787
Received: 2 August 2017 / Revised: 30 September 2017 / Accepted: 3 October 2017 / Published: 15 October 2017
PDF Full-text (5328 KB) | HTML Full-text | XML Full-text
Abstract
Seepage failure in the form of piping can strongly influence the stability of block-in-matrix-soils (bimsoils), as well as weaken and affect the performance of bimsoil structures. The multiple-factor evaluation and optimization play a crucial role in controlling the seepage failure in bimsoil. The
[...] Read more.
Seepage failure in the form of piping can strongly influence the stability of block-in-matrix-soils (bimsoils), as well as weaken and affect the performance of bimsoil structures. The multiple-factor evaluation and optimization play a crucial role in controlling the seepage failure in bimsoil. The aim of this study is to improve the ability to control the piping seepage failure in bimsoil. In this work, the response surface method (RSM) was employed to evaluate and optimize the multiple piping parameters to maximize the critical hydraulic gradient (CHG), in combination with experimental modeling based on a self-developed servo-controlled flow-erosion-stress coupled testing system. All of the studied specimens with rock block percentage (RBP) of 30%, 50%, and 70% were produced as a cylindrical shape (50 mm diameter and 100 mm height) by compaction tests. Four uncertain parameters, such as RBP, soil matrix density, confining pressure, and block morphology were used to fit an optimal response of the CHG. The sensitivity analysis reveals the influential order of the studied factors to CHG. It is found that RBP is the most sensitive factor, the CHG decreases with the increase of RBP, and CHG increases with the increase of confining pressure, soil matrix density, and block angularity. Full article
(This article belongs to the Special Issue Soil Water Conservation: Dynamics and Impact)
Figures

Figure 1

Open AccessArticle Saltwater Intrusion and Freshwater Storage in Sand Sediments along the Coastline: Hydrogeological Investigations and Groundwater Modeling of Nauru Island
Water 2017, 9(10), 788; doi:10.3390/w9100788
Received: 6 August 2017 / Revised: 4 October 2017 / Accepted: 9 October 2017 / Published: 13 October 2017
PDF Full-text (10396 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Water resources sustainable management is a vital issue for small islands where groundwater is often the only available water resource. Nauru is an isolated and uplifted limestone atoll island located in the Pacific Ocean. Politecnico di Milano performed a feasibility study for the
[...] Read more.
Water resources sustainable management is a vital issue for small islands where groundwater is often the only available water resource. Nauru is an isolated and uplifted limestone atoll island located in the Pacific Ocean. Politecnico di Milano performed a feasibility study for the development of sustainable use of groundwater on the island. This paper focuses on the first phase of the study that concerns the conceptual site model development, the hydrogeological characterization and the 2D model implementation. During the project, different activities were performed such as GNSS topographic survey of monitoring wells and groundwater level surveys taking into account tidal fluctuation. This data collection and the analysis of previous studies made it possible to identify the most suitable areas for groundwater sustainable extraction. The characterization findings suggested, unlike previous studies and surveys, the presence of only few drought resilient thin freshwater lenses, taking place in low conductivity sandy deposits, unexpectedly next to the seashore. Thanks to the 2D modeling results, it has been possible to clarify the mechanism that allows the storage of freshwater so close to the sea. Full article
Figures

Figure 1

Open AccessArticle Transient Wave Scattering and Its Influence on Transient Analysis and Leak Detection in Urban Water Supply Systems: Theoretical Analysis and Numerical Validation
Water 2017, 9(10), 789; doi:10.3390/w9100789
Received: 8 September 2017 / Revised: 8 October 2017 / Accepted: 11 October 2017 / Published: 13 October 2017
PDF Full-text (4892 KB) | HTML Full-text | XML Full-text
Abstract
This paper investigates the impacts of non-uniformities of pipe diameter (i.e., an inhomogeneous cross-sectional area along pipelines) on transient wave behavior and propagation in water supply pipelines. The multi-scale wave perturbation method is firstly used to derive analytical solutions for the amplitude evolution
[...] Read more.
This paper investigates the impacts of non-uniformities of pipe diameter (i.e., an inhomogeneous cross-sectional area along pipelines) on transient wave behavior and propagation in water supply pipelines. The multi-scale wave perturbation method is firstly used to derive analytical solutions for the amplitude evolution of transient pressure wave propagation in pipelines, considering regular and random variations of cross-sectional area, respectively. The analytical analysis is based on the one-dimensional (1D) transient wave equation for pipe flow. Both derived results show that transient waves can be attenuated and scattered significantly along the longitudinal direction of the pipeline due to the regular and random non-uniformities of pipe diameter. The obtained analytical results are then validated by extensive 1D numerical simulations under different incident wave and non-uniform pipe conditions. The comparative results indicate that the derived analytical solutions are applicable and useful to describe the wave scattering effect in complex pipeline systems. Finally, the practical implications and influence of wave scattering effects on transient flow analysis and transient-based leak detection in urban water supply systems are discussed in the paper. Full article
Figures

Figure 1

Open AccessArticle SPH Modelling of Hydraulic Jump Oscillations at an Abrupt Drop
Water 2017, 9(10), 790; doi:10.3390/w9100790
Received: 8 September 2017 / Revised: 27 September 2017 / Accepted: 11 October 2017 / Published: 14 October 2017
PDF Full-text (11674 KB) | HTML Full-text | XML Full-text
Abstract
This paper shows the results of the numerical modelling of the transition from supercritical to subcritical flow at an abrupt drop, which can be characterised by the occurrence of oscillatory flow conditions between two different jump types. Weakly-Compressible Smoothed Particle (WCSPH) model was
[...] Read more.
This paper shows the results of the numerical modelling of the transition from supercritical to subcritical flow at an abrupt drop, which can be characterised by the occurrence of oscillatory flow conditions between two different jump types. Weakly-Compressible Smoothed Particle (WCSPH) model was employed and both an algebraic mixing-length model and a two-equation model were used to represent turbulent stresses. The purpose of this paper is to obtain through the SPH model a deeper understanding of the physical features of a flow, which is, in general, difficult to be reproduced numerically, owing to its unstable character. In particular, the experience already gained in SPH simulations of vorticity-dominated flows allows one to assess the fluctuations of hydrodynamic characteristics of the flow field, (e.g., free surface profile downstream of the jump, velocity, pressure and vorticity). Numerical results showed satisfactory agreement with measurements and most of the peculiar features of the flow were qualitatively and quantitatively reproduced. Full article
Figures

Figure 1

Open AccessArticle Batch Test Screening of Industrial Product/Byproduct Filter Materials for Agricultural Drainage Water Treatment
Water 2017, 9(10), 791; doi:10.3390/w9100791
Received: 31 August 2017 / Revised: 30 September 2017 / Accepted: 10 October 2017 / Published: 14 October 2017
PDF Full-text (1037 KB) | HTML Full-text | XML Full-text
Abstract
Filter treatment may be a viable means for removing the nitrate (NO3), phosphate (PO43−), and pesticides discharged with agricultural drainage waters that cause adverse environmental impacts within the U.S. on local, regional, and national scales. Laboratory batch
[...] Read more.
Filter treatment may be a viable means for removing the nitrate (NO3), phosphate (PO43−), and pesticides discharged with agricultural drainage waters that cause adverse environmental impacts within the U.S. on local, regional, and national scales. Laboratory batch test screening for agricultural drainage water treatment potential was conducted on 58 industrial product/byproduct filter materials grouped into six categories: (1) high carbon content media; (2) high iron content media; (3) high aluminum content media; (4) surfactant modified clay/zeolite; (5) coal combustion residuals; and (6) spent foundry sands. Based on a percent contaminant removal criteria of 75% or greater, seven industrial products/byproducts were found to meet this standard for NO3 alone, 44 met this standard for PO43−, and 25 met this standard for the chlorinated triazine herbicide, atrazine. Using a 50% or greater contaminant removal criteria, five of the industrial product/byproduct filter materials exhibited potential for removing NO3, PO43−, and atrazine together; eight showed capability for combined NO3 and PO43− removal; 21 showed capability for combined PO43− and atrazine removal; and nine showed capability for combined NO3 and atrazine removal. The results of this study delineated some potential industrial product/byproduct filter materials for drainage water treatment; however, a complete feasibility evaluation for drainage water treatment of any of these filter materials will require much more extensive testing. Full article
(This article belongs to the Special Issue Additives in Stormwater Filters for Enhanced Pollutant Removal)
Figures

Figure 1

Open AccessArticle Aquifer Vulnerability Assessment for Sustainable Groundwater Management Using DRASTIC
Water 2017, 9(10), 792; doi:10.3390/w9100792
Received: 2 September 2017 / Revised: 8 October 2017 / Accepted: 12 October 2017 / Published: 15 October 2017
PDF Full-text (3588 KB) | HTML Full-text | XML Full-text
Abstract
Groundwater management and protection has been facilitated by computational modeling of aquifer vulnerability and monitoring aquifers using groundwater sampling. The DRASTIC (Depth to water, Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone media, and hydraulic Conductivity) model, an overlay and index
[...] Read more.
Groundwater management and protection has been facilitated by computational modeling of aquifer vulnerability and monitoring aquifers using groundwater sampling. The DRASTIC (Depth to water, Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone media, and hydraulic Conductivity) model, an overlay and index GIS model, has been used for groundwater quality assessment because it relies on simple, straightforward methods. Aquifer vulnerability mapping identifies areas with high pollution potential that can be areas for priority management and monitoring. The objectives of this study are to demonstrate how aquifer vulnerability assessment can be achieved using DRASTIC with high resolution data. This includes calibrating DRASTIC weights using a binary classifier calibration method with a genetic algorithm (Bi-GA), identifying areas of high potential aquifer vulnerability, and selecting potential aquifer monitoring sites using spatial statistics. The aquifer vulnerability results from DRASTIC using Bi-GA were validated with a well database of observed nitrate concentrations for a study area in Indiana. The DRASTIC results using Bi-GA showed that approximately 42.2% of nitrate detections >2 ppm are within “High” and “Very high” vulnerability areas (representing 3.4% of study area) as simulated by DRASTIC. Moreover, 53.4% of the nitrate detections were within the “Moderate” vulnerability class (26.9% of study area), and only 4.3% of the nitrate detections were within the “Low” vulnerability class (60.1% of study area). Nitrates >2 ppm were not detected at all within the “Very low” vulnerability class (9.6% of area). “High” and “Very high” vulnerability areas should be regarded as priority areas for groundwater monitoring and efforts to prevent groundwater contamination. This case study suggests that the approach may be applicable to other areas as part of efforts to target groundwater management efforts. Full article
Figures

Figure 1

Open AccessArticle Hydrological Appraisal of Climate Change Impacts on the Water Resources of the Xijiang Basin, South China
Water 2017, 9(10), 793; doi:10.3390/w9100793
Received: 17 August 2017 / Revised: 27 September 2017 / Accepted: 11 October 2017 / Published: 16 October 2017
PDF Full-text (7638 KB) | HTML Full-text | XML Full-text
Abstract
Assessing the impact of climate change on streamflow is critical to understanding the changes to water resources and to improve water resource management. The use of hydrological models is a common practice to quantify and assess water resources in such situations. In this
[...] Read more.
Assessing the impact of climate change on streamflow is critical to understanding the changes to water resources and to improve water resource management. The use of hydrological models is a common practice to quantify and assess water resources in such situations. In this study, two hydrological models with different structures, e.g., a physically-based distributed model Liuxihe (LXH) and a lumped conceptual model Xinanjiang (XAJ) are employed to simulate the daily runoff in the Xijiang basin in South China, under historical (1964–2013) and future (2014–2099) climate conditions. The future climate series are downscaled from a global climate model (Beijing Climate Centre-Climate System Model, BCC-CSM version 1.1) by a high-resolution regional climate model under two representative concentration pathways—RCP4.5 and RCP8.5. The hydrological responses to climate change via the two rainfall–runoff models with different mathematical structures are compared, in relation to the uncertainties in hydrology and meteorology. It is found that the two rainfall–runoff models successfully simulate the historical runoff for the Xijiang basin, with a daily runoff Nash–Sutcliffe Efficiency of 0.80 for the LXH model and 0.89 for the XAJ model. The characteristics of high flow in the future are also analysed including their frequency (magnitude–return-period relationship). It shows that the distributed model could produce more streamflow and peak flow than the lumped model under the climate change scenarios. However the difference of the impact from the two climate scenarios is marginal on median monthly streamflow. The flood frequency analysis under climate change suggests that flood magnitudes in the future will be more severe than the historical floods with the same return period. Overall, the study reveals how uncertain it can be to quantify water resources with two different but well calibrated hydrological models. Full article
Figures

Figure 1

Open AccessArticle Parametric Modelling of Potential Evapotranspiration: A Global Survey
Water 2017, 9(10), 795; doi:10.3390/w9100795
Received: 23 July 2017 / Revised: 2 October 2017 / Accepted: 13 October 2017 / Published: 16 October 2017
PDF Full-text (10739 KB) | HTML Full-text | XML Full-text
Abstract
We present and validate a global parametric model of potential evapotranspiration (PET) with two parameters that are estimated through calibration, using as explanatory variables temperature and extraterrestrial radiation. The model is tested over the globe, taking advantage of the Food and Agriculture Organization
[...] Read more.
We present and validate a global parametric model of potential evapotranspiration (PET) with two parameters that are estimated through calibration, using as explanatory variables temperature and extraterrestrial radiation. The model is tested over the globe, taking advantage of the Food and Agriculture Organization (FAO CLIMWAT) database that provides monthly averaged values of meteorological inputs at 4300 locations worldwide. A preliminary analysis of these data allows for explaining the major drivers of PET over the globe and across seasons. The model calibration against the given Penman-Monteith values was carried out through an automatic optimization procedure. For the evaluation of the model, we present global maps of optimized model parameters and associated performance metrics, and also contrast its performance against the well-known Hargreaves-Samani method. Also, we use interpolated values of the optimized parameters to validate the predictive capacity of our model against monthly meteorological time series, at several stations worldwide. The results are very encouraging, since even with the use of abstract climatic information for model calibration and the use of interpolated parameters as local predictors, the model generally ensures reliable PET estimations. Exceptions are mainly attributed to irregular interactions between temperature and extraterrestrial radiation, as well as because the associated processes are influenced by additional drivers, e.g., relative humidity and wind speed. However, the analysis of the residuals shows that the model is consistent in terms of parameters estimation and model validation. The parameter maps allow for the direct use of the model wherever in the world, providing PET estimates in case of missing data, that can be further improved even with a short term acquisition of meteorological data. Full article
Figures

Figure 1

Open AccessArticle Optimization Strategy for Improving the Energy Efficiency of Irrigation Systems by Micro Hydropower: Practical Application
Water 2017, 9(10), 799; doi:10.3390/w9100799
Received: 4 August 2017 / Revised: 13 October 2017 / Accepted: 16 October 2017 / Published: 17 October 2017
PDF Full-text (8494 KB) | HTML Full-text | XML Full-text
Abstract
Analyses of possible synergies between energy recovery and water management are essential for achieving sustainable advances in the performance of pressurized irrigation networks. Nowadays, the use of micro hydropower in water systems is being analysed to improve the overall energy efficiency. In this
[...] Read more.
Analyses of possible synergies between energy recovery and water management are essential for achieving sustainable advances in the performance of pressurized irrigation networks. Nowadays, the use of micro hydropower in water systems is being analysed to improve the overall energy efficiency. In this line, the present research is focused on the proposal and development of a novel optimization strategy for increasing the energy efficiency in pressurized irrigation networks by energy recovering. The recovered energy is maximized considering different objective functions, including feasibility index: the best energy converter must be selected, operating in its best efficiency conditions by variation of its rotational speed, providing the required flow in each moment. These flows (previously estimated through farmers’ habits) are compared with registered values of flow in the main line with very suitable calibration results, getting a Nash–Sutcliffe value above 0.6 for different time intervals, and a PBIAS index below 10% in all time interval range. The methodology was applied to a Vallada network obtaining a maximum recovered energy of 58.18 MWh/year (41.66% of the available energy), improving the recovered energy values between 141 and 184% when comparing to energy recovery considering a constant rotational speed. The proposal of this strategy shows the real possibility of installing micro hydropower machines to improve the water–energy nexus management in pressurized systems. Full article
(This article belongs to the Special Issue Water Networks Management: New Perspectives)
Figures

Figure 1

Open AccessArticle Investigation of Geochemical Characteristics and Controlling Processes of Groundwater in a Typical Long-Term Reclaimed Water Use Area
Water 2017, 9(10), 800; doi:10.3390/w9100800
Received: 5 August 2017 / Revised: 12 October 2017 / Accepted: 15 October 2017 / Published: 18 October 2017
PDF Full-text (14471 KB) | HTML Full-text | XML Full-text
Abstract
The usage of reclaimed water can efficiently mitigate water crises, but it may cause groundwater pollution. To clearly understand the potential influences of long-term reclaimed water usage, a total of 91 samples of shallow and deep groundwater were collected from a typical reclaimed
[...] Read more.
The usage of reclaimed water can efficiently mitigate water crises, but it may cause groundwater pollution. To clearly understand the potential influences of long-term reclaimed water usage, a total of 91 samples of shallow and deep groundwater were collected from a typical reclaimed water use area during the dry and rainy seasons. The results suggest both shallow and deep groundwater are mainly naturally alkaline freshwater, which are composed mainly of Ca-HCO3, followed by mixed types such as Ca-Na-HCO3 and Ca-Mg-HCO3. A seasonal desalination trend was observed in both shallow and deep aquifers due to dilution effects in the rainy season. Groundwater chemical compositions in both shallow and deep aquifers are still dominantly controlled by natural processes such as silicate weathering, minerals dissolution and cation exchange. Human activities are also the factors influencing groundwater chemistry. Urbanization has been found responsible for the deterioration of groundwater quality, especially in shallow aquifers, because of the relative thin aquitard. Reclaimed water usage for agricultural irrigation and landscape purposes has nearly no influences on groundwater quality in rural areas due to thick aquitards. Therefore, reclaimed water usage should be encouraged in arid and semiarid areas with proper hydrogeological condition. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Water and Land Footprints and Economic Productivity as Factors in Local Crop Choice: The Case of Silk in Malawi
Water 2017, 9(10), 802; doi:10.3390/w9100802
Received: 31 August 2017 / Revised: 28 September 2017 / Accepted: 10 October 2017 / Published: 18 October 2017
PDF Full-text (1360 KB) | HTML Full-text | XML Full-text
Abstract
In deciding what crops to grow, farmers will look at, among other things, the economically most productive use of the water and land resources that they have access to. However, optimizing water and land use at the farm level may result in total
[...] Read more.
In deciding what crops to grow, farmers will look at, among other things, the economically most productive use of the water and land resources that they have access to. However, optimizing water and land use at the farm level may result in total water and land footprints at the catchment level that are in conflict with sustainable resource use. This study explores how data on water and land footprints, and on economic water and land productivity can inform micro-level decision making of crop choice, in the macro-level context of sustainable resource use. For a proposed sericulture project in Malawi, we calculated water and land footprints of silk along its production chain, and economic water and land productivities. We compared these to current cropping practices, and addressed the implications of water consumption at the catchment scale. We found that farmers may prefer irrigated silk production over currently grown rain-fed staple crops, because its economic water and land productivity is higher than that for currently grown crops. However, because the water footprint of irrigated silk is higher, sericulture will increase the pressure on local water resources. Since water consumption in the catchment generally does not exceed the maximum sustainable footprint, sericulture is a viable alternative crop for farmers in the case study area, as long as silk production remains small-scale (~3% of the area at most) and does not depress local food markets. Full article
(This article belongs to the Special Issue Progress in Water Footprint Assessment)
Figures

Figure 1

Open AccessArticle Optimization of Drinking Water Distribution Systems in Relation to the Effects of Climate Change
Water 2017, 9(10), 803; doi:10.3390/w9100803
Received: 8 September 2017 / Revised: 2 October 2017 / Accepted: 12 October 2017 / Published: 19 October 2017
PDF Full-text (3928 KB) | HTML Full-text | XML Full-text
Abstract
Proper water resources management involves the analysis and resolution of various optimization problems according to climate change effects on the availability and distribution of the resources themselves. Specifically, these conditions require the identification of new resource allocation optimization solutions capable of taking into
[...] Read more.
Proper water resources management involves the analysis and resolution of various optimization problems according to climate change effects on the availability and distribution of the resources themselves. Specifically, these conditions require the identification of new resource allocation optimization solutions capable of taking into account the water resource losses due to climate change scenarios. As is well known, Southern Italy is a region that is potentially very sensitive to climate change. In this paper, a 1717 km2 area, corresponding to the province of Crotone, was analyzed as a study case. This area is characterized by a sufficient availability of resources as a whole as compared to the needs of the users, but has an unbalanced distribution of water through its various systems. After identifying water resource allocations in detail for this area, an optimization solution accounting for the expected reduced availability of water resources in the context of climate change was created and was compared with the optimization solution for current water availability. Full article
Figures

Figure 1

Open AccessArticle Melting Characteristics of Snow Cover on Tidewater Glaciers in Hornsund Fjord, Svalbard
Water 2017, 9(10), 804; doi:10.3390/w9100804
Received: 16 August 2017 / Revised: 13 October 2017 / Accepted: 16 October 2017 / Published: 19 October 2017
PDF Full-text (5820 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, the Svalbard area, especially its southern section, has been characterised by an exceptionally thin snow cover, which has a significant impact of the annual mass balance of glaciers. The objective of this study was to determine melting processes of the
[...] Read more.
In recent years, the Svalbard area, especially its southern section, has been characterised by an exceptionally thin snow cover, which has a significant impact of the annual mass balance of glaciers. The objective of this study was to determine melting processes of the snow cover deposited on 11 glaciers that terminate into Hornsund Fjord during the melting period of 2014. The study included analyses of snow pits and snow cores, meteorological data collected from automatic weather stations and Polish Polar Station Hornsund, and supervised classification of six Landsat 8 images for assessing the progress of snow cover melting. The calculated Snow-Covered Area (SCA) varied from 98% at the beginning of the melting season to 43% at the end of August. The melting vertical gradient on Hansbreen was −0.34 m 100 m−1, leading to surface melting of −1.4 cm water equivalent (w.e.) day−1 in the ablation zone (c. 200 m a.s.l. (above sea level)) and −0.7 cm w.e. day−1 in the accumulation zone (c. 400 m a.s.l.). Furthermore, the study identified several observed features such as low snow depth in the accumulation zone of the Hornsund glaciers, a large proportion of the snow layers (12–27%) produced by rain-on-snow events, and a frequent occurrence of summer thermal inversions (80% annually), indicating that the area is experiencing intensive climate changes. Full article
Figures

Figure 1

Open AccessArticle Atmospheric and Surface-Condition Effects on CO2 Exchange in the Liaohe Delta Wetland, China
Water 2017, 9(10), 806; doi:10.3390/w9100806
Received: 15 August 2017 / Revised: 11 September 2017 / Accepted: 16 October 2017 / Published: 20 October 2017
PDF Full-text (7393 KB) | HTML Full-text | XML Full-text
Abstract
The eddy covariance method was used to study the CO2 budget of the Liaohe Delta reed wetland in northern China during 2012–2015. The changes in environmental factors (including meteorology, vegetation, hydrology, and soil) were analyzed simultaneously. The change in the trend of
[...] Read more.
The eddy covariance method was used to study the CO2 budget of the Liaohe Delta reed wetland in northern China during 2012–2015. The changes in environmental factors (including meteorology, vegetation, hydrology, and soil) were analyzed simultaneously. The change in the trend of the CO2 concentration in the reed wetland was similar to global changes over the four years. The average annual CO2 accumulation was 2.037 kg·CO2·m−2, ranging from 1.472 to 2.297 kg·CO2·m−2. The seasonal characteristics of the CO2 exchange included high CO2 absorption in June and July, and high emissions in April and from September to October, with the highest emissions in July 2015. The average temperatures from 2013 to 2015 were higher than the 50-year average, largely due to increased temperatures in winter. Precipitation was below the 50-year average, mainly because of low precipitation in summer. The average wind speed was less than the 50-year average, and sunshine duration decreased each year. The CO2 exchange and environmental factors had a degree of correlation or consistency. The contribution of meteorology, vegetation, hydrology, and soil to the CO2 budget was analyzed using the partial least squares method. Water and soil temperature had a greater effect on the CO2 exchange variability. The regression equation of the CO2 budget was calculated using the significant contributing factors, including temperature, precipitation, relative humidity, water-table level, salinity, and biomass. The model fit explained more than 70% of the CO2 exchange, and the simulation results were robust. Full article
Figures

Figure 1

Open AccessArticle The Spatial and Temporal Structure of Extreme Rainfall Trends in South Korea
Water 2017, 9(10), 809; doi:10.3390/w9100809
Received: 9 August 2017 / Revised: 12 October 2017 / Accepted: 19 October 2017 / Published: 22 October 2017
PDF Full-text (4328 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The spatial and temporal structures of extreme rainfall trends in South Korea are investigated in the current study. The trends in the annual maximum rainfall series are detected and their spatial distribution is analyzed. The scaling exponent is employed as an index representing
[...] Read more.
The spatial and temporal structures of extreme rainfall trends in South Korea are investigated in the current study. The trends in the annual maximum rainfall series are detected and their spatial distribution is analyzed. The scaling exponent is employed as an index representing the temporal structure. The temporal structure of the annual maximum series is calculated and spatially analyzed. Subsequently, the block bootstrap based Mann-Kendall test is employed detect the trend in the scaling exponent series subsampled by the annual maximum rainfalls using a moving window. Significant trends are detected in a small number of stations and there are no significant trends in many stations for the annual maximum rainfall series. There is a large variability in the temporal structures of the extreme rainfall events. Additionally, the variations of the scaling exponent estimates for each month within a rainy season are larger than the variation of the scaling exponent estimates on an annual basis. Significant trends in the temporal structures are observed at many stations unlike the trend test results of annual maximum rainfall series. Decreasing trends are observed at many stations located in the coastal area, while increasing trends are observed in the inland area. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Data-Driven Study of Discolouration Material Mobilisation in Trunk Mains
Water 2017, 9(10), 811; doi:10.3390/w9100811
Received: 14 September 2017 / Revised: 19 October 2017 / Accepted: 20 October 2017 / Published: 24 October 2017
PDF Full-text (1867 KB) | HTML Full-text | XML Full-text
Abstract
It has been shown that sufficiently high velocities can cause the mobilisation of discolouration material in water distribution systems. However, how much typical hydraulic conditions affect the mobilisation of discolouration material has yet to be thoroughly investigated. In this paper, results are presented
[...] Read more.
It has been shown that sufficiently high velocities can cause the mobilisation of discolouration material in water distribution systems. However, how much typical hydraulic conditions affect the mobilisation of discolouration material has yet to be thoroughly investigated. In this paper, results are presented from real turbidity and flow observations collected from three U.K. trunk main networks over a period of two years and 11 months. A methodology is presented that determines whether discolouration material has been mobilised by hydraulic forces and the origin of that material. The methodology found that the majority of turbidity observations over 1 Nephelometric Turbidity Units (NTU) could be linked to a preceding hydraulic force that exceeded an upstream pipe’s hydraulically preconditioned state. The findings presented in this paper show the potential in proactively managing the hydraulic profile to reduce discolouration risk and improve customer service. Full article
Figures

Figure 1

Open AccessArticle A Hybrid Heuristic Optimization Approach for Leak Detection in Pipe Networks Using Ordinal Optimization Approach and the Symbiotic Organism Search
Water 2017, 9(10), 812; doi:10.3390/w9100812
Received: 22 September 2017 / Revised: 19 October 2017 / Accepted: 22 October 2017 / Published: 24 October 2017
PDF Full-text (2389 KB) | HTML Full-text | XML Full-text
Abstract
A new transient-based hybrid heuristic approach is developed to optimize a transient generation process and to detect leaks in pipe networks. The approach couples the ordinal optimization approach (OOA) and the symbiotic organism search (SOS) to solve the optimization problem by means of
[...] Read more.
A new transient-based hybrid heuristic approach is developed to optimize a transient generation process and to detect leaks in pipe networks. The approach couples the ordinal optimization approach (OOA) and the symbiotic organism search (SOS) to solve the optimization problem by means of iterations. A pipe network analysis model (PNSOS) is first used to determine steady-state head distribution and pipe flow rates. The best transient generation point and its relevant valve operation parameters are optimized by maximizing the objective function of transient energy. The transient event is created at the chosen point, and the method of characteristics (MOC) is used to analyze the transient flow. The OOA is applied to sift through the candidate pipes and the initial organisms with leak information. The SOS is employed to determine the leaks by minimizing the sum of differences between simulated and computed head at the observation points. Two synthetic leaking scenarios, a simple pipe network and a water distribution network (WDN), are chosen to test the performance of leak detection ordinal symbiotic organism search (LDOSOS). Leak information can be accurately identified by the proposed approach for both of the scenarios. The presented technique makes a remarkable contribution to the success of leak detection in the pipe networks. Full article
Figures

Figure 1

Open AccessArticle The Impact of a Check Dam on Groundwater Recharge and Sedimentation in an Ephemeral Stream
Water 2017, 9(10), 813; doi:10.3390/w9100813
Received: 18 September 2017 / Revised: 17 October 2017 / Accepted: 19 October 2017 / Published: 24 October 2017
PDF Full-text (2987 KB) | HTML Full-text | XML Full-text
Abstract
Despite the widespread presence of groundwater recharge check dams, there are few studies that quantify their functionality. The objectives of this study are (i) to assess groundwater recharge in an ephemeral river with and without a check dam and (ii) to assess sediment
[...] Read more.
Despite the widespread presence of groundwater recharge check dams, there are few studies that quantify their functionality. The objectives of this study are (i) to assess groundwater recharge in an ephemeral river with and without a check dam and (ii) to assess sediment build-up in the check-dam reservoir. Field campaigns were carried out to measure water flow, water depth, and check-dam topography to establish water volume, evaporation, outflow, and recharge relations, as well as sediment build-up. To quantify the groundwater recharge, a water-balance approach was applied at two locations: at the check dam reservoir area and at an 11 km long natural stretch of the river upstream. Prediction intervals were computed to assess the uncertainties of the results. During the four years of operation, the check dam (storage capacity of 25,000 m3) recharged the aquifer with an average of 3.1 million m3 of the 10.4 million m3 year−1 of streamflow (30%). The lower and upper uncertainty limits of the check dam recharge were 0.1 and 9.6 million m3 year−1, respectively. Recharge from the upstream stretch was 1.5 million m3 year−1. These results indicate that check dams are valuable structures for increasing groundwater resources in semi-arid regions. Full article
Figures

Figure 1

Open AccessArticle Assessing the Water-Resources Potential of Istanbul by Using a Soil and Water Assessment Tool (SWAT) Hydrological Model
Water 2017, 9(10), 814; doi:10.3390/w9100814
Received: 15 September 2017 / Revised: 16 October 2017 / Accepted: 20 October 2017 / Published: 24 October 2017
PDF Full-text (3631 KB) | HTML Full-text | XML Full-text
Abstract
Uncertainties due to climate change and population growth have created a critical situation for many megacities. Investigating spatio-temporal variability of water resources is, therefore, a critical initial step for water-resource management. This paper is a first study on the evaluation of water-budget components
[...] Read more.
Uncertainties due to climate change and population growth have created a critical situation for many megacities. Investigating spatio-temporal variability of water resources is, therefore, a critical initial step for water-resource management. This paper is a first study on the evaluation of water-budget components of water resources in Istanbul using a high-resolution hydrological model. In this work, the water resources of Istanbul and surrounding watersheds were modeled using the Soil and Water Assessment Tool (SWAT), which is a continuous-time, semi-distributed, process-based model. The SWAT-CUP program was used for calibration/validation of the model with uncertainty analysis using the SUFI-2 algorithm over the period 1977–2013 at 25 gauge stations. The results reveal that the annual blue-water potential of Istanbul is 3.5 billion m3, whereas the green-water flow and storage are 2.9 billion m3 and 0.7 billion m3, respectively. Watersheds located on the Asian side of the Istanbul megacity yield more blue-water resources compared to the European side, and constitute 75% of the total potential water resources. The model highlights the water potential of the city under current circumstances and gives an insight into its spatial distribution over the region. This study provides a strong basis for forthcoming studies concerning better water-resources management practices, climate change and water-quality studies, as well as other socio-economic scenario analyses in the region. Full article
Figures

Figure 1

Review

Jump to: Editorial, Research, Other

Open AccessReview Robust Adaptation Research in High Mountains: Integrating the Scientific, Social, and Ecological Dimensions of Glacio-Hydrological Change
Water 2017, 9(10), 739; doi:10.3390/w9100739
Received: 1 August 2017 / Revised: 25 September 2017 / Accepted: 25 September 2017 / Published: 28 September 2017
PDF Full-text (225 KB) | HTML Full-text | XML Full-text
Abstract
Climate-related changes in glacierized watersheds are widely documented, stimulating adaptive responses among the 370 million people living in glacier-influenced watersheds as well as aquatic and riparian ecosystems. The situation denotes important interdependencies between science, society, and ecosystems, yet integrative approaches to the study
[...] Read more.
Climate-related changes in glacierized watersheds are widely documented, stimulating adaptive responses among the 370 million people living in glacier-influenced watersheds as well as aquatic and riparian ecosystems. The situation denotes important interdependencies between science, society, and ecosystems, yet integrative approaches to the study of adaptation to such changes remain scarce in both the mountain- and non-mountain-focused adaptation scholarship. Using the example of glacio-hydrological change, it is argued here that this analytical limitation impedes the identification, development, and implementation of “successful” adaptations. In response, the paper introduces three guiding principles for robust adaptation research in glaciated mountain regions. Principle 1: Adaptation research should integrate detailed analyses of watershed-specific glaciological and hydro-meteorological conditions; glacio-hydrological changes are context-specific and therefore cannot be assumed to follow idealized trajectories of “peak water”. Principle 2: Adaptation research should consider the complex interplay between glacio-hydrological changes and socio-economic, cultural, and political conditions; responses to environmental changes are non-deterministic and therefore not deducible from hydrological changes alone. Principle 3: Adaptation research should be attentive to interdependencies, feedbacks, and tradeoffs between human and ecological responses to glacio-hydrological change; research that does not evaluate these socio-ecological dynamics may lead to maladaptive adaptation plans. These principles call attention to the linked scientific, social, and ecological dimensions of adaptation, and offer a point of departure for future climate change adaptation research in high mountains. Full article
(This article belongs to the Special Issue Global Warming Impacts on Mountain Glaciers and Communities)
Open AccessFeature PaperReview The Potential for the Treatment of Antimony-Containing Wastewater by Iron-Based Adsorbents
Water 2017, 9(10), 794; doi:10.3390/w9100794
Received: 1 September 2017 / Revised: 11 October 2017 / Accepted: 12 October 2017 / Published: 16 October 2017
PDF Full-text (274 KB) | HTML Full-text | XML Full-text
Abstract
Antimony (Sb) and its compounds are considered as global priority pollutants. Elevated concentrations of antimony in natural and industrial process wastewater are of global concern, particularly given interest in the potential toxicity and harm to the environment from aquatic exposure. Iron-based materials for
[...] Read more.
Antimony (Sb) and its compounds are considered as global priority pollutants. Elevated concentrations of antimony in natural and industrial process wastewater are of global concern, particularly given interest in the potential toxicity and harm to the environment from aquatic exposure. Iron-based materials for treatment by adsorption are widely regarded to have potential merit for the removal of trace contaminants from water and especially in the search for efficient and low-cost techniques. In this paper, we review the application of iron-based materials in the sorption treatment of antimony contaminated water. The interaction of Sb is discussed in relation to adsorption performance, influencing factors, mechanism, modelling of adsorption (isotherm, kinetic and thermodynamic models), advantages, drawbacks and the recent achievements in the field. Although iron-based adsorbents show promise, the following three aspects are in need of further study. Firstly, a select number of iron based binary metal oxide adsorbents should be further explored as they show superior performance compared to other systems. Secondly, the possibility of redox reactions and conversion between Sb(III) and Sb(V) during the adsorption process is unclear and requires further investigation. Thirdly, in order to achieve optimized control of preferential adsorption sites and functional groups, the mechanism of antimony removal has to be qualitatively and quantitatively resolved by combining the advantages of advanced characterization techniques such as Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy (XPS), Atomic force microscope(AFM), X-ray absorption near edge structure(XANES), and other spectroscopic methods. We provide details on the achievements and limitations of each of these stages and point to the need for further research. Full article
(This article belongs to the Special Issue Heavy Metals and Potentially Toxic Elements (PTEs) in Water)
Open AccessReview Interpolation in Time Series: An Introductive Overview of Existing Methods, Their Performance Criteria and Uncertainty Assessment
Water 2017, 9(10), 796; doi:10.3390/w9100796
Received: 31 July 2017 / Revised: 3 October 2017 / Accepted: 13 October 2017 / Published: 17 October 2017
PDF Full-text (547 KB) | HTML Full-text | XML Full-text
Abstract
A thorough review has been performed on interpolation methods to fill gaps in time-series, efficiency criteria, and uncertainty quantifications. On one hand, there are numerous available methods: interpolation, regression, autoregressive, machine learning methods, etc. On the other hand, there are many methods and
[...] Read more.
A thorough review has been performed on interpolation methods to fill gaps in time-series, efficiency criteria, and uncertainty quantifications. On one hand, there are numerous available methods: interpolation, regression, autoregressive, machine learning methods, etc. On the other hand, there are many methods and criteria to estimate efficiencies of these methods, but uncertainties on the interpolated values are rarely calculated. Furthermore, while they are estimated according to standard methods, the prediction uncertainty is not taken into account: a discussion is thus presented on the uncertainty estimation of interpolated/extrapolated data. Finally, some suggestions for further research and a new method are proposed. Full article
(This article belongs to the Special Issue Quantifying Uncertainty in Integrated Catchment Studies)
Figures

Figure 1

Open AccessReview Essentials of Endorheic Basins and Lakes: A Review in the Context of Current and Future Water Resource Management and Mitigation Activities in Central Asia
Water 2017, 9(10), 798; doi:10.3390/w9100798
Received: 31 July 2017 / Revised: 10 October 2017 / Accepted: 13 October 2017 / Published: 21 October 2017
PDF Full-text (3268 KB) | HTML Full-text | XML Full-text
Abstract
Endorheic basins (i.e., land-locked drainage networks) and their lakes can be highly sensitive to variations in climate and adverse anthropogenic activities, such as overexploitation of water resources. In this review paper, we provide a brief overview of one major endorheic basin on each
[...] Read more.
Endorheic basins (i.e., land-locked drainage networks) and their lakes can be highly sensitive to variations in climate and adverse anthropogenic activities, such as overexploitation of water resources. In this review paper, we provide a brief overview of one major endorheic basin on each continent, plus a number of endorheic basins in Central Asia (CA), a region where a large proportion of the land area is within this type of basin. We summarize the effects of (changing) climate drivers and land surface–atmosphere feedbacks on the water balance. For the CA region, we also discuss key anthropogenic activities, related water management approaches and their complex relationship with political and policy issues. In CA a substantial increase in irrigated agriculture coupled with negative climate change impacts have disrupted the fragile water balance for many endorheic basins and their lakes. Transboundary integrated land and water management approaches must be developed to facilitate adequate climate change adaptation and possible mitigation of the adverse anthropogenic influence on endorheic basins in CA. Suitable climate adaptation, mitigation and efficient natural resource management technologies and methods are available, and are developing fast. A number of these are discussed in the paper, but these technologies alone are not sufficient to address pressing water resource issues in CA. Food–water–energy nexus analyses demonstrate that transboundary endorheic basin management requires transformational changes with involvement of all key stakeholders. Regional programs, supported by local governments and international donors, which incorporate advanced adaptation technologies, water resource research and management capacity development, are essential for successful climate change adaptation efforts in CA. However, there is a need for an accelerated uptake of such programs, with an emphasis on unification of approaches, as the pressures resulting from climate change and aggravated by human mismanagement of natural water resources leave very little time for hesitation. Full article
(This article belongs to the Special Issue The Future of Water Management in Central Asia)
Figures

Figure 1

Open AccessReview Fogs: Physical Basis, Characteristic Properties, and Impacts on the Environment and Human Health
Water 2017, 9(10), 807; doi:10.3390/w9100807
Received: 15 July 2017 / Revised: 2 October 2017 / Accepted: 12 October 2017 / Published: 20 October 2017
PDF Full-text (380 KB) | HTML Full-text | XML Full-text
Abstract
This work presents a selective overview of natural fogs in terms of fog types, forms and states of occurrence, physical, micro-physical, chemical and dynamic properties, basic characterizing parameters, etc. In focus are related achievements and contributions reported mainly during the last decade and
[...] Read more.
This work presents a selective overview of natural fogs in terms of fog types, forms and states of occurrence, physical, micro-physical, chemical and dynamic properties, basic characterizing parameters, etc. In focus are related achievements and contributions reported mainly during the last decade and a half, as a result of both laboratory studies and field observations. Processes of homogeneous and heterogeneous nucleation are analyzed in the aspects of condensation, nuclei diversity and specifics, as related to the activation, growth and deposition of fog droplets. The effect is highlighted of the water vapor’s partial pressure on the surface tension of the liquid water–air interface and the freezing point of the water droplets. Some problems and aspects of fog modeling, parameterization, and forecasting are outlined and discussed on the examples of newly developed relevant 1D/3D theoretical models. Important issues of fog impacts on the air quality, ecosystems, water basins, societal life, and human health are also addressed and discussed, particularly in cases of anthropogenically modified (chemical, radioactive, etc.) fogs. In view of reducing the possible negative effects of fogs, conclusions are drawn concerning the new demands and challenges to fog characterization imposed by the changing natural and social environment and the needs for new data on and approaches to more adequate observations of fog-related events. Full article
Figures

Figure 1

Other

Jump to: Editorial, Research, Review

Open AccessTechnical Note Study on Applicability of Conceptual Hydrological Models for Flood Forecasting in Humid, Semi-Humid Semi-Arid and Arid Basins in China
Water 2017, 9(10), 719; doi:10.3390/w9100719
Received: 23 August 2017 / Revised: 6 September 2017 / Accepted: 15 September 2017 / Published: 28 September 2017
PDF Full-text (7759 KB) | HTML Full-text | XML Full-text
Abstract
Flood simulation and forecasting in various types of watersheds is a hot issue in hydrology. Conceptual hydrological models have been widely applied to flood forecasting for decades. With the development of economy, modern China faces with severe flood disasters in all types of
[...] Read more.
Flood simulation and forecasting in various types of watersheds is a hot issue in hydrology. Conceptual hydrological models have been widely applied to flood forecasting for decades. With the development of economy, modern China faces with severe flood disasters in all types of watersheds include humid, semi-humid semi-arid and arid watersheds. However, conceptual model-based flood forecasting in semi-humid semi-arid and arid regions is still challenging. To investigate the applicability of conceptual hydrological models for flood forecasting in the above mentioned regions, three typical conceptual models, include Xinanjiang (XAJ), mix runoff generation (MIX) and northern Shannxi (NS), are applied to 3 humid, 3 semi-humid semi-arid, and 3 arid watersheds. The rainfall-runoff data of the 9 watersheds are analyzed based on statistical analysis and information theory, and the model performances are compared and analyzed based on boxplots and scatter plots. It is observed the complexity of drier watershed data is higher than that of the wetter watersheds. This indicates the flood forecasting is harder in drier watersheds. Simulation results indicate all models perform satisfactorily in humid watersheds and only NS model is applicable in arid watersheds. Model with consideration of saturation excess runoff generation (XAJ and MIX) perform better than the infiltration excess-based NS model in semi-humid semi-arid watersheds. It is concluded more accurate mix runoff generation theory, more stable and efficient numerical solution of infiltration equation and rainfall data with higher spatial-temporal resolution are main obstacles for conceptual model-based flood simulation and forecasting. Full article
Figures

Figure 1