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Water, Volume 10, Issue 9 (September 2018) – 177 articles

Cover Story (view full-size image): Large wood is a relevant element of river habitats. During floods, it can lead to clogging at bridges and thus cause their obstruction followed by floodplain inundation. Thus, river management must balance between the ecological needs and the hazard management perspective. The simulation of the overall dynamics of large wood within a river reach, from the recruitment of trees to mobilization, transport and deposition, supports the prioritization of areas with an importance for ecology and an importance for flood discharge improvement. View this paper.
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13 pages, 1667 KiB  
Article
Maternal Environment Effect of Warming and Eutrophication on the Emergence of Curled Pondweed, Potamogeton crispus L.
by Chao Li, Tao Wang, Min Zhang and Jun Xu
Water 2018, 10(9), 1285; https://doi.org/10.3390/w10091285 - 19 Sep 2018
Cited by 21 | Viewed by 3765
Abstract
Maternal effects may play an important role in life history and offspring performance of aquatic plants. Performance and response of maternal and offspring aquatic plants can affect population dynamics and community composition. Understanding maternal effect can help to fill a gap in the [...] Read more.
Maternal effects may play an important role in life history and offspring performance of aquatic plants. Performance and response of maternal and offspring aquatic plants can affect population dynamics and community composition. Understanding maternal effect can help to fill a gap in the knowledge of aquatic plant life cycles, and provide important insights for species’ responses to climate change and eutrophication. This study showed that maternal warming and eutrophication significantly affected the early life stages of curled pondweed, Potamogeton crispus, a submerged macrophyte. Propagule in warmed condition had higher germination percentages and a shorter mean germination time than those under ambient conditions. However, propagule germination in phosphorus addition treatment was inhibited due to the negative effect of eutrophication, e.g., phytoplankton competition and deteriorated underwater light. Meanwhile, elevated temperature led to a decrease of total nitrogen concentrations and an increase of carbon: nitrogen ratios in plant tissues, which may suggest that P. crispus will allocate more nutrients to propagules in order to resist the adverse effects of high temperature. A subsequent germination experiment in the same ambient condition showed that maternal warming promoted seedling emergence in contrast to maternal phosphorus addition. Consequently, global warming could modify population growth via maternal environmental effects on early life histories, while increased anthropogenic nutrient inputs may result in a decreased submerged macrophyte. These maternal effects on offspring performance may change competition and the survival of early life-history stages under climate warming and eutrophication through changing the ecological stoichiometry of plant tissue. Full article
(This article belongs to the Special Issue Plants in Aquatic Ecosystems: Current Trends and Future Directions)
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24 pages, 2657 KiB  
Article
Thermal and Hydrodynamic Changes under a Warmer Climate in a Variably Stratified Hypereutrophic Reservoir
by Raymond Mark Lee, Trent Wade Biggs and Xing Fang
Water 2018, 10(9), 1284; https://doi.org/10.3390/w10091284 - 19 Sep 2018
Cited by 12 | Viewed by 4220
Abstract
We quantified effects of future climate warming on temperature and stability in a variably stratified, hypereutrophic reservoir with large fluctuations in water level by calibrating a 2-D model (CE-QUAL-W2, version 3.7.1, Portland State University, Portland, USA) of reservoir hydrodynamics using a time series [...] Read more.
We quantified effects of future climate warming on temperature and stability in a variably stratified, hypereutrophic reservoir with large fluctuations in water level by calibrating a 2-D model (CE-QUAL-W2, version 3.7.1, Portland State University, Portland, USA) of reservoir hydrodynamics using a time series (1992 to 2011) of inflow and air and water temperature. The model was then forced with increased air temperature projected by an ensemble of climate models that accounted for complex local topography and seasonality, with greater warming in summer. Warming increased annual evaporation rates by 2.6 to 7.9%. Water temperature increased by 0.44 (whole-reservoir; p < 0.05), 0.47 (epilimnion; p < 0.01), and 0.30 °C (hypolimnion; p < 0.05) per 1 °C increase in air temperature. Thickness of the epilimnion and hypolimnion diminished, with expansion of the metalimnion. Schmidt stability correlated with mean water depth over a wide range of depths (3.9 to 8.1 m; Adj. R2 = 0.91 to 0.93; p < 0.001). Increased air temperature increased mean annual stability by 6.1 to 23.6 J m−2 when depth was large and the reservoir stratified, but when depth was low (due to combined low inflow and, in preceding years, high withdrawals), inhibiting stratification, then water temperatures increased evenly (and more) throughout the vertical profile so change in mean annual stability was near zero (−0.1 to 1.1 J m−2). Combined effects of reservoir management (volume, timing, and elevation of water withdrawal) and climate warming (temperature of air and benthic sediment) can impact the hydrodynamic regime differently under variably stratified conditions with implications for release of phosphorus from sediment and vertical transport of phosphorus to the euphotic zone. Full article
(This article belongs to the Section Urban Water Management)
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18 pages, 4758 KiB  
Article
Building ANN-Based Regional Multi-Step-Ahead Flood Inundation Forecast Models
by Li-Chiu Chang, Mohd Zaki M. Amin, Shun-Nien Yang and Fi-John Chang
Water 2018, 10(9), 1283; https://doi.org/10.3390/w10091283 - 19 Sep 2018
Cited by 85 | Viewed by 7674
Abstract
A regional inundation early warning system is crucial to alleviating flood risks and reducing loss of life and property. This study aims to provide real-time multi-step-ahead forecasting of flood inundation maps during storm events for flood early warnings in inundation-prone regions. For decades, [...] Read more.
A regional inundation early warning system is crucial to alleviating flood risks and reducing loss of life and property. This study aims to provide real-time multi-step-ahead forecasting of flood inundation maps during storm events for flood early warnings in inundation-prone regions. For decades, the Kemaman River Basin, located on the east coast of the West Malaysia Peninsular, has suffered from monsoon floods that have caused serious damage. The downstream region with an area of approximately 100 km2 located on the east side of this basin is selected as the study area. We explore and implement a hybrid ANN-based regional flood inundation forecast system in the study area. The system combines two popular artificial neural networks—the self-organizing map (SOM) and the recurrent nonlinear autoregressive with exogenous inputs (RNARX)—to sequentially produce regional flood inundation maps during storm events. The results show that: (1) the 4 × 4 SOM network can effectively cluster regional inundation depths; (2) RNARX networks can accurately forecast the long-term (3–12 h) regional average inundation depths; and (3) the hybrid models can produce adequate real-time regional flood inundation maps. The proposed ANN-based model was shown to very quickly carry out multi-step-ahead forecasting of area-wide inundation depths with sufficient lead time (up to 12 h) and can visualize the forecasted results on Google Earth using user devices to help decision makers and residents take precautionary measures against flooding. Full article
(This article belongs to the Special Issue Flood Forecasting Using Machine Learning Methods)
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18 pages, 1401 KiB  
Article
How Environmental Protection Motivation Influences on Residents’ Recycled Water Reuse Behaviors: A Case Study in Xi’an City
by Xiaojun Liu, Yuqi He, Hanliang Fu, Baiyu Chen, Mengmeng Wang and Zelin Wang
Water 2018, 10(9), 1282; https://doi.org/10.3390/w10091282 - 19 Sep 2018
Cited by 33 | Viewed by 5779
Abstract
Pro-environmental behaviors related to reclaimed water reuse are regarded as important motivations for both environmental protection and the use of reclaimed water, and these motivations could affect the citizens’ decision whether they will accept reclaimed water reuse. A hypothesis model was developed as [...] Read more.
Pro-environmental behaviors related to reclaimed water reuse are regarded as important motivations for both environmental protection and the use of reclaimed water, and these motivations could affect the citizens’ decision whether they will accept reclaimed water reuse. A hypothesis model was developed as the NAM (Norm Activation Model) has changed, and this hypothesis model was used to explore the factors that affect the citizen’s decision about the reclaimed water reuse, and obtain a better understanding of the mechanism of urban citizens in environmental protection and the related outcomes. First, 584 samples were used to verify the reliability and validity of data, and AMOS21.0 was used to test the goodness-of-fit between the sample data and the hypothesis model. Based on this, the applicability of the improved NAM was verified through the study of recycled water reuse. The hypothesis model was used to analyze its direct influences, showing that environmental motivation has positive influences on the citizens’ acceptance toward recycled water reuse. Besides, Bootstrap method was used to verify the mediation effect, proving that awareness of consequences regarding environmental pollution caused by human activities and ascription of responsibility could strengthen the citizens’ motivation to protect the environment. Full article
(This article belongs to the Section Urban Water Management)
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13 pages, 857 KiB  
Article
Irrigation Canal System Delivery Scheduling Based on a Particle Swarm Optimization Algorithm
by Ye Liu, Ting Yang, Rong-Heng Zhao, Yi-Bo Li, Wen-Ju Zhao and Xiao-Yi Ma
Water 2018, 10(9), 1281; https://doi.org/10.3390/w10091281 - 19 Sep 2018
Cited by 22 | Viewed by 5494
Abstract
Reasonable planning of water delivery schedules for canal systems can reduce losses caused by water seepage and improve the utilization efficiency of irrigation water. Empirical methods of water delivery scheduling for canal systems usually cause problems such as insufficient discharge, excessively delayed water [...] Read more.
Reasonable planning of water delivery schedules for canal systems can reduce losses caused by water seepage and improve the utilization efficiency of irrigation water. Empirical methods of water delivery scheduling for canal systems usually cause problems such as insufficient discharge, excessively delayed water delivery, and large losses under given water requirements. In this study, a canal water delivery scheduling model was set up, and a customized algorithm based on particle swarm optimization was proposed. Typical heuristic algorithms often become trapped in local optima and often search inefficiently under numerous constraints; however, the proposed algorithm can overcome these typical problems. The proposed method was evaluated for two typical canal irrigation systems, and the results showed that the algorithm is robust and efficient and can quickly meet the water delivery optimization schedules for canal irrigation systems. Compared with empirical methods, the algorithm reduced the leakage loss of delivered water from 7.29% to 5.40%, and 8.97% to 7.46% for the two tested canal systems. The discharge of the main canal is relatively stable, which can reduce the difficulty of head gate adjustment. The proposed optimization algorithm can provide practical and efficient water delivery schedules for irrigation canal systems. Full article
(This article belongs to the Section Water Resources Management, Policy and Governance)
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12 pages, 1413 KiB  
Article
Interval Multi-Attribute Decision of Watershed Ecological Compensation Schemes Based on Projection Pursuit Cluster
by Ming Zhang, Jinghong Zhou and Runjuan Zhou
Water 2018, 10(9), 1280; https://doi.org/10.3390/w10091280 - 19 Sep 2018
Cited by 10 | Viewed by 4102
Abstract
The ecological compensation scheme of water pollution in the basin is a result of the interplay between upstream and downstream cities, which is of great significance to the guidance of regional economic development. The purpose of this paper is to propose a multi-attribute [...] Read more.
The ecological compensation scheme of water pollution in the basin is a result of the interplay between upstream and downstream cities, which is of great significance to the guidance of regional economic development. The purpose of this paper is to propose a multi-attribute scheme decision algorithm, which is expressed in the form of interval number, to reduce the uncertainty of decision results and improve the reliability of decision results. This method first uses the Monte Carlo simulation technique to produce a large number of random samples in the various attributes of the decision matrix to construct the random decision-making matrix (DMM). Then, according to the overall dispersion and local concentration of the random DMM, the clustering method of the projection pursuit is adopted. By accelerating the genetic algorithm, the weight and the best projection eigenvalues of each scheme are optimized, and the sorting results of the decision-making cases are obtained based on the projected eigenvalues. The results of the case study show that the uncertainty of the decision results is greater when the number of random simulations is very low; as the number of random simulations increases, the result of the decision becomes more and more stable and clear, and the uncertainty decreases. The results of the Duncan test show that, scheme 2, which is composed of financial compensation and remote development, is better than other schemes, and the decision making is more reasonable. The result of this decision has certain values for the ecological compensation scheme in Suzhou and Jiaxing cities, and the proposed method can be applied in similar range multi-attribute scheme decision-making issues. Full article
(This article belongs to the Special Issue Hydroeconomic Analysis for Sustainable Water Management)
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22 pages, 2728 KiB  
Article
Projected Changes in Hydrological Extremes in the Yangtze River Basin with an Ensemble of Regional Climate Simulations
by Huanghe Gu, Zhongbo Yu, Chuanguo Yang and Qin Ju
Water 2018, 10(9), 1279; https://doi.org/10.3390/w10091279 - 19 Sep 2018
Cited by 42 | Viewed by 5624
Abstract
This paper estimates the likely impacts of future climate change on streamflow, especially the hydrological extremes over the Yangtze River basin. The future climate was projected by the Coordinated Regional Climate Downscaling Experiment in East Asia (CORDEX-EA) initiative for the periods 2020–2049 under [...] Read more.
This paper estimates the likely impacts of future climate change on streamflow, especially the hydrological extremes over the Yangtze River basin. The future climate was projected by the Coordinated Regional Climate Downscaling Experiment in East Asia (CORDEX-EA) initiative for the periods 2020–2049 under two representative concentration pathways (RCP) 4.5 and 8.5 emission scenarios. The bias corrected outputs from five regional climate models (RCMs) were used in conjunction with the variable infiltration capacity (VIC) macroscale hydrological model to produce hydrological projections. For the future climate of the Yangtze River basin, outputs from an ensemble of RCMs indicate that the annual mean temperature will increase for 2020–2049 by 1.81 °C for RCP4.5 and by 2.26 °C for RCP8.5. The annual mean precipitation is projected to increase by 3.62% under RCP4.5 and 7.65% under RCP8.5. Overall, increases in precipitation are amplified in streamflow, and the change in streamflow also shows significant temporal and spatial variations and large divergence between regional climate models. At the same time, the maximum streamflow in different durations are also projected to increase at three mainstream gauging stations based on flood frequency analysis. In particular, larger increases in maximum 1-day streamflow (+14.24% on average) compared to 5-day and 15-day water volumes (+12.79% and +10.24%) indicate that this projected extreme streamflow increase would be primarily due to intense short-period rainfall events. It is necessary to consider the impacts of climate change in future water resource management. Full article
(This article belongs to the Section Hydrology)
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24 pages, 2343 KiB  
Article
Framework for WASH Sector Data Improvements in Data-Poor Environments, Applied to Accra, Ghana
by Rembrandt H. E. M. Koppelaar, May N. Sule, Zoltán Kis, Foster K. Mensah, Xiaonan Wang, Charalampos Triantafyllidis, Koen H. van Dam and Nilay Shah
Water 2018, 10(9), 1278; https://doi.org/10.3390/w10091278 - 18 Sep 2018
Cited by 7 | Viewed by 7366
Abstract
Improvements in water, sanitation and hygiene (WASH) service provision are hampered by limited open data availability. This paper presents a data integration framework, collects the data and develops a material flow model, which aids data-based policy and infrastructure development for the WASH sector. [...] Read more.
Improvements in water, sanitation and hygiene (WASH) service provision are hampered by limited open data availability. This paper presents a data integration framework, collects the data and develops a material flow model, which aids data-based policy and infrastructure development for the WASH sector. This model provides a robust quantitative mapping of the complete anthropogenic WASH flow-cycle: from raw water intake to water use, wastewater and excreta generation, discharge and treatment. This approach integrates various available sources using a process-chain bottom-up engineering approach to improve the quality of WASH planning. The data integration framework and the modelling methodology are applied to the Greater Accra Metropolitan Area (GAMA), Ghana. The highest level of understanding of the GAMA WASH sector is achieved, promoting scenario testing for future WASH developments. The results show 96% of the population had access to improved safe water in 2010 if sachet and bottled water was included, but only 67% if excluded. Additionally, 66% of 338,000 m3 per day of generated wastewater is unsafely disposed locally, with 23% entering open drains, and 11% sewage pipes, indicating poor sanitation coverage. Total treated wastewater is <0.5% in 2014, with only 18% of 43,000 m3 per day treatment capacity operational. The combined data sets are made available to support research and sustainable development activities. Full article
(This article belongs to the Section Urban Water Management)
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19 pages, 2418 KiB  
Article
Detecting the Dominant Cause of Streamflow Decline in the Loess Plateau of China Based onthe Latest Budyko Equation
by Jing Zhao, Shengzhi Huang, Qiang Huang, Hao Wang and Guoyong Leng
Water 2018, 10(9), 1277; https://doi.org/10.3390/w10091277 - 18 Sep 2018
Cited by 21 | Viewed by 4538
Abstract
Quantifying the relative contributions of climate variability and human activity to streamflow change is important for effective water resource use and management. Four sub-catchments of the Wei River Basin (WRB) in the Loess Plateau in China were selected as the study region, where [...] Read more.
Quantifying the relative contributions of climate variability and human activity to streamflow change is important for effective water resource use and management. Four sub-catchments of the Wei River Basin (WRB) in the Loess Plateau in China were selected as the study region, where the evolution of parameter α from the latest Budyko equation (Wang-Tang equation) was explored using an 11-year moving window. The elasticity of streamflow was derived from the climatic aridity index, represented by the ratio of annual potential evaporation ( E P ) to annual precipitation ( P ), and catchment characteristics as represented by α . The effects of climate change and human activities on streamflow change during 1971–2010 were quantified with climate elasticity and decomposition methods. The contributions of different types of human activities to streamflow were further empirically determined using the water and soil conservation method. Results indicate that (1) under the same climate condition ( P and E P ), a higher value of α caused an increase in evaporation rate ( E / P ) and a decrease in runoff. Changes in these hydrological variables led to a subsequent reduction in streamflow in the WRB; (2) The absolute value of the precipitation elasticity was larger than the potential evaporation elasticity, indicating that streamflow change was more sensitive to precipitation; (3) The results based on the two methods were consistent. Climate change and human activities contributed to the decrease in streamflow by 29% and 71%, respectively, suggesting that human activities have exerted more profound impacts on streamflow in the study region; (4) Contributions of different water and soil conservation measures to streamflow reduction were calculated and sorted in descending order: Irrigation, industrial and domestic consumption, terrace, afforestation, reservoirs, check-dams, then grass-planting. Full article
(This article belongs to the Section Hydrology)
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11 pages, 2868 KiB  
Article
Diurnal and Semidiurnal Cyclicity of Radon (222Rn) in Groundwater, Giardino Spring, Central Apennines, Italy
by Marino Domenico Barberio, Francesca Gori, Maurizio Barbieri, Andrea Billi, Roberto Devoti, Carlo Doglioni, Marco Petitta, Federica Riguzzi and Sergio Rusi
Water 2018, 10(9), 1276; https://doi.org/10.3390/w10091276 - 18 Sep 2018
Cited by 27 | Viewed by 6588
Abstract
Understanding natural variations of Rn (222Rn) concentrations is the fundamental prerequisite of using this radioactive gas as a tracer, or even precursor, of natural processes, including earthquakes. In this work, Rn concentrations in groundwater were continuously measured over a seven-month period, [...] Read more.
Understanding natural variations of Rn (222Rn) concentrations is the fundamental prerequisite of using this radioactive gas as a tracer, or even precursor, of natural processes, including earthquakes. In this work, Rn concentrations in groundwater were continuously measured over a seven-month period, during 2017, in the Giardino Spring, Italy, together with groundwater levels in a nearby well installed into a fractured regional aquifer. Data were processed to reduce noise, and then analyzed to produce the Fourier spectra of Rn concentrations and groundwater levels. These spectra were compared with the spectrum of tidal forces. Results showed that diurnal and semidiurnal cycles of Rn concentrations, and filtered oscillations of groundwater levels, in the nearby well, are correlated with solar and luni-solar components of tidal forces, and suggested no correlation with the principal lunar components. Therefore, influencing factors linked to solar cycles, such as daily oscillations of temperature and atmospheric pressure, and related rock deformations, may have played a role in Rn concentrations and groundwater levels. An open question remains regarding the correlation, which is documented elsewhere, of Rn concentrations and groundwater levels with the lunar components of the solid Earth tides. Full article
(This article belongs to the Special Issue Isotopes in Hydrology and Hydrogeology)
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13 pages, 1837 KiB  
Article
A Novel System for Water Disinfection with UV Radiation
by Bassam A. Younis, Laura Mahoney and Nicholas Palomo
Water 2018, 10(9), 1275; https://doi.org/10.3390/w10091275 - 18 Sep 2018
Cited by 9 | Viewed by 6010
Abstract
We present a novel system for water disinfection with ultra-violet (UV) radiation. In this system, the UV lamps do not come into contact with the water and hence remain free of fouling. The system incorporates a diffusor and a nozzle, with stationary guide [...] Read more.
We present a novel system for water disinfection with ultra-violet (UV) radiation. In this system, the UV lamps do not come into contact with the water and hence remain free of fouling. The system incorporates a diffusor and a nozzle, with stationary guide vanes built into each. Their combined purpose is to reduce the hydraulic losses while imparting a strong swirl component to the flow. The swirl significantly enhances turbulent mixing processes and provides a self-cleansing mechanism that renders the system tolerant to high levels of turbidity and scaling. The hydrodynamic performance of the system was optimized using Computational Fluid Dynamics, while the manufacture of its key components was accomplished using advanced mechanical design software and three-dimensional (3D) printing. Biodosimetry testing with the bacteriophage MS2 indicated the delivery of a UV dose of 215.6 mJ/cm2. This produced a 6.9 log10 reduction of E. coli and 7.12 log10 reduction of MS2. Assessment of the system with hard water containing high Ca, Mg, and Fe concentrations, and with water with turbidity of 18 NTU indicated that the log10 removal of E. coli remained above 5. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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19 pages, 10289 KiB  
Article
Developing Hydro-Meteorological Thresholds for Shallow Landslide Initiation and Early Warning
by Benjamin B. Mirus, Michael D. Morphew and Joel B. Smith
Water 2018, 10(9), 1274; https://doi.org/10.3390/w10091274 - 18 Sep 2018
Cited by 67 | Viewed by 6246
Abstract
Consistent relations between shallow landslide initiation and associated rainfall characteristics remain difficult to identify, due largely to the complex hydrological and geological processes causing slopes to be predisposed to failure and those processes that subsequently trigger failures. Considering the importance of hillslope hydrology [...] Read more.
Consistent relations between shallow landslide initiation and associated rainfall characteristics remain difficult to identify, due largely to the complex hydrological and geological processes causing slopes to be predisposed to failure and those processes that subsequently trigger failures. Considering the importance of hillslope hydrology for rainfall-induced landsliding, we develop and test a method for identifying hybrid hydro-meteorological thresholds to assess landslide initiation potential. We outline a series of steps for using a landslide inventory in combination with triggering rainfall and antecedent wetness to identify empirical thresholds that can inform landslide early warning systems. The method is semi-automated but remains flexible enough to allow threshold developers to consider data inputs and various performance metrics with different priorities for balancing failed versus false alarms. We demonstrate the utility of our approach for two monitoring sites near Seattle, Washington and in Portland, Oregon, USA, to develop daily bilinear thresholds within a two-dimensional parameter space, which rely on accurate 24 h forecasts, measured recent rainfall and in situ soil saturation. Although there were no prior landslide thresholds for Portland, our new hybrid threshold for the Seattle area outperforms established rainfall-only thresholds for the same region. Introducing subsurface hydrologic monitoring into landslide initiation thresholds has the potential to greatly improve early warning capabilities and help reduce losses. Full article
(This article belongs to the Special Issue Landslide Hydrology)
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19 pages, 2920 KiB  
Article
Trend and Change-Point Analysis of Streamflow and Sediment Discharge of the Gongshui River in China during the Last 60 Years
by Li-Ping Guo, Qiang Yu, Peng Gao, Xiao-Fei Nie, Kai-Tao Liao, Xiu-Long Chen, Jian-Min Hu and Xing-Min Mu
Water 2018, 10(9), 1273; https://doi.org/10.3390/w10091273 - 18 Sep 2018
Cited by 22 | Viewed by 4529
Abstract
The Gongshui River basin exhibits one of the most serious soil erosion areas in southern China, and has always been the key control area of national soil and water conservation programs. This study used daily precipitation, streamflow, and sediment concentration data collected from [...] Read more.
The Gongshui River basin exhibits one of the most serious soil erosion areas in southern China, and has always been the key control area of national soil and water conservation programs. This study used daily precipitation, streamflow, and sediment concentration data collected from 1957 to 2015 from the main hydrological stations of the Gongshui River to investigate streamflow and sediment discharge variations and their responses to precipitation and human activities. The Mann-Kendall and Pettitt’s test were used for trend and change-point detection. The double mass curve (DMC) method was employed to quantify the effects of precipitation change and human activities on hydrological regime shifts. The results showed insignificant trends of both annual precipitation and streamflow for all stations, while the sediment discharge of most stations exhibited significant decreasing trends. Change-point analyses revealed that all hydrologic stations except Mazhou had transition years. The estimation via DMC indicated that after the change point years, there was a rapid reduction in sediment discharge at Hanlinqiao, Fengkeng, Julongtan, Xiashan, and Chawu stations, but not at Mazhou, Ruijin, and Yangxinjian stations. Human activity provided a significantly greater contribution to sediment discharge than precipitation. The evidence clearly indicates that the degree and extension of conservation or destruction measures and the construction of large- and medium-sized reservoirs were the major factors significantly decreasing or increasing annual sediment discharge of the Gongshui River. This work could serve as the basis for decision making regarding river basin water resources management to estimate the effects of anthropogenic impacts on water and sediment discharge variations during the last few decades, thereby guiding adaptation and protection of the water resources of the Gongshui River flowing into the Poyang Lake. Full article
(This article belongs to the Special Issue Watershed Hydrology, Erosion and Sediment Transport Processes )
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18 pages, 4619 KiB  
Article
Collapsing Mechanisms of the Typical Cohesive Riverbank along the Ningxia–Inner Mongolia Catchment
by Guosheng Duan, Anping Shu, Matteo Rubinato, Shu Wang and Fuyang Zhu
Water 2018, 10(9), 1272; https://doi.org/10.3390/w10091272 - 18 Sep 2018
Cited by 14 | Viewed by 5605
Abstract
As one of the major sediment sources in rivers, bank collapse often occurs in the Ningxia–Inner Mongolia catchment and, to date, it caused substantial social, economic and environmental problems in both local areas and downstream locations. To provide a better understanding of this [...] Read more.
As one of the major sediment sources in rivers, bank collapse often occurs in the Ningxia–Inner Mongolia catchment and, to date, it caused substantial social, economic and environmental problems in both local areas and downstream locations. To provide a better understanding of this phenomenon, this study consisted of modifying the existing Bank Stability and Toe Erosion Model (BSTEM), commonly used to investigate similar phenomena, introducing new assumptions and demonstrating its applicability by comparing numerical results obtained against field data recorded at six gauging stations (Qingtongxia, Shizuishan, Bayan Gol, Sanhuhekou, Zhaojunfen, and Toudaoguai). Furthermore, the impact of multiple factors typical of flood and dry seasons on the collapse rate was investigated, and insights obtained should be taken into consideration when completing future projects of river adaptation and river restoration. Full article
(This article belongs to the Special Issue Advances in Hydraulics and Hydroinformatics)
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18 pages, 1506 KiB  
Article
Community-Managed Water Supply Systems in Rural Uganda: The Role of Participation and Capacity Development
by Daniel Etongo, G. Honor Fagan, Consolata Kabonesa and Richard Asaba B.
Water 2018, 10(9), 1271; https://doi.org/10.3390/w10091271 - 18 Sep 2018
Cited by 21 | Viewed by 9394
Abstract
Over 85% of Uganda’s 34 million people depend on rural water supply systems and the current water and environment sector performance report (2017) reports an 84% functionality of rural water sources such as boreholes and shallow wells with a hand pump. Ensuring the [...] Read more.
Over 85% of Uganda’s 34 million people depend on rural water supply systems and the current water and environment sector performance report (2017) reports an 84% functionality of rural water sources such as boreholes and shallow wells with a hand pump. Ensuring the continued operation of water points, and in keeping with participatory theory, the water user’s committees (WUCs) should also be a vehicle for empowering communities while bringing about greater equity of use. However, WUC members do not acquire the knowledge and skills they need by default but require different types of training. This study sought to evaluate community participation and capacity development in WUCs in relation to community-managed water supply systems. A shared dialogue workshop (SDW), as well as 642 randomly selected households across 17 villages in two Parishes in Lwengo district, southern Uganda were considered. Results indicated that 41.7% of surveyed households used an unprotected source while up to 30% had a member in a WUC. Fifty-two percent of households had never made any financial contributions to a WUC, while 34.6% did so on an ad hoc basis. This paper examines the relationship between participation, mobilization, and financial contributions. The chi-square test indicated mobilization has no impact on household financial contributions to a WUC. However, the majority of even those households that were mobilized made a payment only occasionally, and specifically when the source broke down. Additionally, the test result reveals that there is no difference between better off and relatively poor households in their contributions to a WUC, an indication that other factors influence such decisions. Training activities, especially on the operation and maintenance of water points and to undertake minor repairs, were mostly provided by non-governmental organizations (NGOs)/project staff. Abandoned boreholes, lack of rehabilitation activities, and loss of enthusiasm are all indications that the technical, financial, and institutional performance of community-managed water supply systems needs improvement. Full article
(This article belongs to the Section Water Resources Management, Policy and Governance)
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19 pages, 7824 KiB  
Article
A Systematic Operation Program of a Hydropower Plant Based on Minimizing the Principal Stress: Haditha Dam Case Study
by Jing Li, Ameen Mohammed Salih Ameen, Thamer Ahmad Mohammad, Nadhir Al-Ansari and Zaher Mundher Yaseen
Water 2018, 10(9), 1270; https://doi.org/10.3390/w10091270 - 18 Sep 2018
Cited by 10 | Viewed by 5985
Abstract
Dam operation and management have become more complex recently because of the need for considering hydraulic structure sustainability and environmental protect on. An Earthfill dam that includes a powerhouse system is considered as a significant multipurpose hydraulic structure. Understanding the effects of running [...] Read more.
Dam operation and management have become more complex recently because of the need for considering hydraulic structure sustainability and environmental protect on. An Earthfill dam that includes a powerhouse system is considered as a significant multipurpose hydraulic structure. Understanding the effects of running hydropower plant turbines on the dam body is one of the major safety concerns for earthfill dams. In this research, dynamic analysis of earthfill dam, integrated with a hydropower plant system containing six vertical Kaplan turbines (i.e., Haditha dam), is investigated. In the first stage of the study, ANSYS-CFX was used to represent one vertical Kaplan turbine unit by designing a three-dimensional (3-D) finite element (FE) model. This model was used to differentiate between the effect of turbine units’ operation on dam stability in accordance to maximum and minimum reservoir upstream water levels, and the varying flowrates in a fully open gate condition. In the second stage of the analysis, an ANSYS-static modeling approach was used to develop a 3-D FE earthfill dam model. The water pressure pattern determined on the boundary of the running turbine model is transformed into the pressure at the common area of the dam body with turbines. The model is inspected for maximum and minimum upstream water levels. Findings indicate that the water stress fluctuations on the dam body are proportional to the inverse distance from the turbine region. Also, it was found that the cone and outlet of the hydropower turbine system are the most affected regions when turbine is running. Based on the attained results, a systematic operation program was proposed in order to control the running hydropower plant with minimized principal stress at selected nodes on the dam model and the six turbines. Full article
(This article belongs to the Section Water Resources Management, Policy and Governance)
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13 pages, 3060 KiB  
Article
Preliminary Study of Computational Time Steps in a Physically Based Distributed Rainfall–Runoff Model
by Yun Seok Choi, Mun-Ju Shin and Kyung Tak Kim
Water 2018, 10(9), 1269; https://doi.org/10.3390/w10091269 - 18 Sep 2018
Cited by 6 | Viewed by 3452
Abstract
The choice of the computational time step (dt) value and the method for setting dt can have a bearing on the accuracy and performance of a simulation, and this effect has not been comprehensively researched across different simulation conditions. In this [...] Read more.
The choice of the computational time step (dt) value and the method for setting dt can have a bearing on the accuracy and performance of a simulation, and this effect has not been comprehensively researched across different simulation conditions. In this study, the effects of the fixed time step (FTS) method and the automatic time step (ATS) method on the simulated runoff of a distributed rainfall–runoff model were compared. The results revealed that the ATS method had less peak flow variability than the FTS method for the virtual catchment. In the FTS method, the difference in time step had more impact on the runoff simulation results than the other factors such as differences in the amount of rainfall, the density of the stream network, or the spatial resolution of the input data. Different optimal parameter values according to the computational time step were found when FTS and ATS were used in a real catchment, and the changes in the optimal parameter values were smaller in ATS than in FTS. The results of our analyses can help to yield reliable runoff simulation results. Full article
(This article belongs to the Special Issue GIS-Based Hydrology and Water Quality Modeling)
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20 pages, 5926 KiB  
Article
Risk Assessment of Upper-Middle Reaches of Luanhe River Basin in Sudden Water Pollution Incidents Based on Control Units of Water Function Areas
by Yao Xiao, Suiliang Huang, Jianguo Zhou, Fanqing Kong, Mingzhe Liu and Ying Li
Water 2018, 10(9), 1268; https://doi.org/10.3390/w10091268 - 17 Sep 2018
Cited by 9 | Viewed by 4361
Abstract
Upper-middle reaches of Luanhe River Basin belongs to Haihe River Basin and it is a pretty important water source to North China, especially to Tianjin and Tangshan Cities, Hebei. Based on control units of the water function areas and the sub-basins the working [...] Read more.
Upper-middle reaches of Luanhe River Basin belongs to Haihe River Basin and it is a pretty important water source to North China, especially to Tianjin and Tangshan Cities, Hebei. Based on control units of the water function areas and the sub-basins the working units were produced. The index system for environmental risk source hazard was constructed by adopting the pressure state response (PSR) environmental analysis model. The environment risk sources are identified, and their hazard grade assessment is performed. In the environmental risk source hazard an assessment index system, namely “downstream characteristics of environmental risk sources” is added by taking the fact into account that environmental risk sources themselves are affected by different functional areas (working units) downstream of the rivers. Through collecting hazard data, determining their standards and weights for environment risk sources, the fuzzy comprehensive evaluation method is used to calculate the risk source hazard grades and the vulnerability grades of the working units. Using the one-dimensional exponential decay river model for pollutants in rivers, the hazard grade evaluation method of working units is established. This consists of two parts: (1) The risk source hazard grade of the working unit itself, and (2) the impact of the risk sources upstream on the working unit downstream of the rivers. Combining the hazard grade with the vulnerability grade of the working unit, the risk grade of the working unit is evaluated through the risk matrix. The risk zones of the watershed are realized by merging working units in the same control units of the water function areas with the same risk grades. The risk zoning of sudden water pollution incidents in the upper and middle reaches of Luanhe River Basin is obtained by applying the above risk zoning method. It is found that there are 55 risk zones in total, including three highest risk zones, 15 higher risk zones, 14 lower risk zones, 23 lowest risk zones. These results indicate that the upper and middle reaches of River Luanhe are overall at low risk. The corresponding management methods for the different risk zones are suggested. Full article
(This article belongs to the Section Urban Water Management)
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22 pages, 3007 KiB  
Article
Irrigation Management Based on Reservoir Operation with an Improved Weed Algorithm
by Mohammad Ehteram, Vijay P. Singh, Hojat Karami, Khosrow Hosseini, Mojgan Dianatikhah, Md. Shabbir Hossain, Chow Ming Fai and Ahmed El-Shafie
Water 2018, 10(9), 1267; https://doi.org/10.3390/w10091267 - 17 Sep 2018
Cited by 19 | Viewed by 4259
Abstract
Water scarcity is a serious problem throughout the world. One critical part of this problem is supplying sufficient water to meet irrigation demands for agricultural production. The present study introduced an improved weed algorithm for reservoir operation with the aim of decreasing irrigation [...] Read more.
Water scarcity is a serious problem throughout the world. One critical part of this problem is supplying sufficient water to meet irrigation demands for agricultural production. The present study introduced an improved weed algorithm for reservoir operation with the aim of decreasing irrigation deficits. The Aswan High Dam, one of the most important dams in Egypt, was selected for this study to supply irrigation demands. The improved weed algorithm (IWA) had developed local search ability so that the exploration ability for the IWA increased and it could escape from local optima. Three inflows (low, medium and high) to the reservoir were considered for the downstream demands. For example, the average solution for the IWA at high inflow was 0.985 while it was 1.037, 1.040, 1.115 and 1.121 for the weed algorithm (WA), bat algorithm (BA), improved particle swarm optimization algorithm (IPSOA) and genetic algorithm (GA). This meant that the IWA decreased the objective function for high inflow by 5.01%, 5.20%, 11.65% and 12% compared to the WA, BA, IPSOA and GA, respectively. The computational time for the IWA at high inflow was 22 s, which was 12%, 18%, 24% and 29% lower than the WA, BA, IPSOA and GA, respectively. Results indicated that the IWA could meet the demands at all three inflows. The reliability index for the IWA for the three inflows was greater than the WA, BA, IPSOA and GA, meaning that the released water based on IWA could well supply the downstream demands. Thus, the improved weed algorithm is suggested for solving complex problems in water resources management. Full article
(This article belongs to the Special Issue Modelling and Management of Irrigation System)
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17 pages, 6205 KiB  
Article
Development of RiverBox—An ArcGIS Toolbox for River Bathymetry Reconstruction
by Tomasz Dysarz
Water 2018, 10(9), 1266; https://doi.org/10.3390/w10091266 - 17 Sep 2018
Cited by 18 | Viewed by 7252
Abstract
The main purpose of the present research is to develop software for reconstruction of the river bed on the basis of sparse cross-section measurements. The tools prepared should support the process of hydrodynamic model preparation for simulation of river flow. Considering the formats [...] Read more.
The main purpose of the present research is to develop software for reconstruction of the river bed on the basis of sparse cross-section measurements. The tools prepared should support the process of hydrodynamic model preparation for simulation of river flow. Considering the formats of available data and the requirements of modern modeling techniques, the prepared software is fully integrated with the GIS environment. The scripting language Python 2.7 implemented in ArcGIS 10.5.1 was chosen for this purpose. Two study cases were selected to validate and test the prepared procedures. These are stream reaches in Poland. The first is located on the Warta river, and the second on the Ner river. The data necessary for the whole procedure are: a digital elevation model, measurements of the cross-sections in the form of points, and two polyline layers representing an arbitrary river centerline and river banks. In the presented research the concept of a channel-oriented coordinate system is applied. The elevations are linearly interpolated along the longitudinal and transversal directions. The interpolation along the channel is implemented in three computational schemes linking different tools available in ArcGIS and ArcToolbox. A simplified comparison of memory usage and computational time is presented. The scheme linking longitudinal and spatial interpolation algorithms seems to be the most advantageous. Full article
(This article belongs to the Special Issue Applications of Remote Sensing and GIS in Hydrology)
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20 pages, 6062 KiB  
Article
An Improved Grid-Xinanjiang Model and Its Application in the Jinshajiang Basin, China
by Changqing Meng, Jianzhong Zhou, Deyu Zhong, Chao Wang and Jun Guo
Water 2018, 10(9), 1265; https://doi.org/10.3390/w10091265 - 17 Sep 2018
Cited by 12 | Viewed by 3986
Abstract
A modified form of the distributed Grid-Xinanjiang model (GXAJ) characterizing the infiltration excess and saturation excess runoff mechanisms coupled to a two-source potential evapotranspiration model (TSPE) was proposed to simulate the hydrological process and study the spatiotemporal pattern of the precipitation, evapotranspiration, and [...] Read more.
A modified form of the distributed Grid-Xinanjiang model (GXAJ) characterizing the infiltration excess and saturation excess runoff mechanisms coupled to a two-source potential evapotranspiration model (TSPE) was proposed to simulate the hydrological process and study the spatiotemporal pattern of the precipitation, evapotranspiration, and soil moisture in the Jinshajiang River basin. In the flow routing module, the flow is routed by the physically nonlinear Muskingum–Cunge method. The TSPE model can calculate the spatiotemporal variation of the potential canopy transpiration (CT), interception evaporation (IE), and potential soil evaporation (SE). Subsequently, the calculated potential evapotranspiration (PE) is coupled to the GXAJ model to calculate the water budget in each grid. An a priori parameter estimation was developed to obtain the spatially varied parameters from geographical data, including digital elevation model (DEM) data, soil data, vegetation data, and routing data. Hydrometeorological data were interpolated to 4750 grids with cell sizes of 10 km × 10 km by the Thiessen Polygon method. The DEM data was used to extract the flow direction, river length, hillslope, and channel slopes and to adjust the altitude-related meteorological variables. The reprocessed Moderate Resolution Imaging Spectroradiometer (MODIS) leaf area index (LAI) from the Beijing Normal University (BNU) dataset, which has a spatial resolution of 1 km × 1 km, was used to obtain the spatiotemporal variation in the LAI. The developed GXAJ model was applied to three sub-basins in the Jinshajiang River basin and was compared to the traditional GXAJ model. The developed GXAJ model satisfactorily reproduced the streamflow at each catchment outlet and matched the peak discharges better than the traditional GXAJ model for both the dry and wet seasons. The uneven distribution of the simulated mean annual evapotranspiration in the whole watershed was closely related to the vegetation types, ranging from 189.81 to 585.45 mm. Forest and woodland, shrubland, grassland, and cropland were shown to have mean annual evapotranspiration values of 485.6, 289.4, 275.9, and 392.3 mm, respectively. The ratios of the annual evapotranspiration to precipitation (E/P) of the forest, woodland, shrubland, grassland, and cropland were 54, 83, 53, and 48%, respectively. Full article
(This article belongs to the Section Hydrology)
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14 pages, 2107 KiB  
Article
Effect of Water Management Technology Used in Trout Culture on Water Quality in Fish Ponds
by Marcin Sidoruk and Ireneusz Cymes
Water 2018, 10(9), 1264; https://doi.org/10.3390/w10091264 - 17 Sep 2018
Cited by 25 | Viewed by 5735
Abstract
Pond management requires that a specific fish culture is conducted while taking into account both production possibilities and profitability, as well as the impact it may have on the natural environment. This study aimed to evaluate the effect of three water management systems [...] Read more.
Pond management requires that a specific fish culture is conducted while taking into account both production possibilities and profitability, as well as the impact it may have on the natural environment. This study aimed to evaluate the effect of three water management systems used in rainbow trout culture on water quality in fish ponds. It was conducted at six trout farms and differing in water management strategy. After water had flown through the fishing ponds, its quality was significantly less impaired at farms operating in the flow and cascade systems. In turn, waters discharged from farms using the recirculation system were characterized by the poorest quality and lowest values on the Water Quality Index (WQI). It was found that the flow and cascade systems can be used to maintain the water quality and give less fish mortality for trout. It has been shown that the use of a water recirculation system in rainbow trout cultures significantly affects the quality of water in fishponds and can potentially lead to suppression of fish resistance and in extreme cases, to fish death. This study will help fish farmers in choosing the optimal variant of water management, taking into account both the best fish health with the least negative impact of fish farms on the environment. Full article
(This article belongs to the Special Issue Freshwater Quality as a Driver of Aquatic Ecosystem Health)
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17 pages, 3339 KiB  
Article
Development and Integration of Sub-Daily Flood Modelling Capability within the SWAT Model and a Comparison with XAJ Model
by Dachen Li, Simin Qu, Peng Shi, Xueqiu Chen, Feng Xue, Jianfeng Gou and Wenhao Zhang
Water 2018, 10(9), 1263; https://doi.org/10.3390/w10091263 - 15 Sep 2018
Cited by 26 | Viewed by 5175
Abstract
To date, floods have become one of the most severe natural disasters on Earth. Flood forecasting with hydrological models is an important non-engineering measure for flood control and disaster reduction. The Xin’anjiang (XAJ) model is the most widely used hydrological model in China [...] Read more.
To date, floods have become one of the most severe natural disasters on Earth. Flood forecasting with hydrological models is an important non-engineering measure for flood control and disaster reduction. The Xin’anjiang (XAJ) model is the most widely used hydrological model in China for flood forecasting, while the Soil and Water Assessment Tool (SWAT) model is widely applied for daily and monthly simulation and has shown its potential for flood simulation. The objective of this paper is to evaluate the performance of the SWAT model in simulating floods at a sub-daily time-scale in a slightly larger basin and compare that with the XAJ model. Taking Qilijie Basin (southeast of China) as a study area, this paper developed the XAJ model and SWAT model at a sub-daily time-scale. The results showed that the XAJ model had a better performance than the sub-daily SWAT model regarding relative runoff error (RRE) but the SWAT model performed well according to relative peak discharge error (RPE) and error of occurrence time of peak flow (PTE). The SWAT model performed unsatisfactorily in simulating low flows due to the daily calculation of base flow but behaved quite well in simulating high flows. We also evaluated the effect of spatial scale on the SWAT model. The results showed that the SWAT model had a good applicability at different spatial scales. In conclusion, the sub-daily SWAT model is a promising tool for flood simulation though more improvements remain to be studied further. Full article
(This article belongs to the Section Hydrology)
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13 pages, 5144 KiB  
Article
Experimental Study on the Impact Characteristics of Cavitation Bubble Collapse on a Wall
by Jing Luo, Weilin Xu, Jun Deng, Yanwei Zhai and Qi Zhang
Water 2018, 10(9), 1262; https://doi.org/10.3390/w10091262 - 15 Sep 2018
Cited by 43 | Viewed by 7212
Abstract
As a hydrodynamic phenomenon, cavitation is a main concern in many industries such as water conservancy, the chemical industry and medical care. There are many studies on the generation, development and collapse of cavitation bubbles, but there are few studies on the variation [...] Read more.
As a hydrodynamic phenomenon, cavitation is a main concern in many industries such as water conservancy, the chemical industry and medical care. There are many studies on the generation, development and collapse of cavitation bubbles, but there are few studies on the variation of the cyclic impact strength on walls from the collapse of cavitation bubbles. In this paper, a high-speed dynamic acquisition and analysis system and a pressure measuring system are combined to study the impact of a cavitation bubble generated near a wall for various distances between the cavitation bubble and the wall. The results show that (1) with the discriminating criteria of the impact pressure borne by the wall, the critical conditions for the generation of a micro-jet in the collapse process of the cavitation bubbles are obtained, and therefore collapses of cavitation bubbles near the wall are mainly divided into primary impact area collapses, secondary impact area collapses and slow release area collapses; (2) it can be seen from the impact strength of the cavitation bubble collapse on the wall surface that the impact of cavitation bubbles on the wall surface during the first collapse decreases as γ (the dimensionless distance between the cavitation bubble and the wall) increases, but the impact of the second collapse on the wall surface increases first and then decreases sharply. When γ is less than 1.33, the impact on the wall surface is mainly from the first collapse. When γ is between 1.33 and 2.37, the impact on the wall surface is mainly from the second collapse. These conclusions have potential theoretical value for the utilization or prevention and control technologies for cavitation erosion. Full article
(This article belongs to the Special Issue Advances in Hydraulics and Hydroinformatics)
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16 pages, 7036 KiB  
Article
Assessing the Analytical Solution of One-Dimensional Gravity Wave Model Equations Using Dam-Break Experimental Measurements
by Wenjun Liu, Bo Wang, Yunliang Chen, Chao Wu and Xin Liu
Water 2018, 10(9), 1261; https://doi.org/10.3390/w10091261 - 15 Sep 2018
Cited by 13 | Viewed by 5153
Abstract
The one-dimensional gravity wave model (GWM) is the result of ignoring the convection term in the Saint-Venant Equations (SVEs), and has the characteristics of fast numerical calculation and low stability requirements. To study its performances and limitations in 1D dam-break flood, this paper [...] Read more.
The one-dimensional gravity wave model (GWM) is the result of ignoring the convection term in the Saint-Venant Equations (SVEs), and has the characteristics of fast numerical calculation and low stability requirements. To study its performances and limitations in 1D dam-break flood, this paper verifies the model using a dam-break experiment. The experiment was carried out in a large-scale flume with depth ratios (initial downstream water depth divided by upstream water depth) divided into 0 and 0.1~0.4. The data were collected by image processing technology, and the hydraulic parameters, such as water depth, flow discharge, and wave velocity, were selected for comparison. The experimental results show that the 1D GWM performs an area with constant hydraulic parameters, which is quite different from the experimental results in the dry downstream case. For a depth ratio of 0.1, the second weak discontinuity point, which is connected to the steady zone in the 1D GWM, moves upstream, which is contrary to the experimental situation. For depth ratios of 0.2~0.4, the moving velocity of the second weak discontinuity point is faster than the experimental value, while the velocity of the shock wave is slower. However, as the water depth ratio increases, the hydraulic parameters calculated by 1D GWM in the steady zone gradually approach the experimental value. Full article
(This article belongs to the Special Issue Advances in Hydraulics and Hydroinformatics)
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23 pages, 7285 KiB  
Article
Future Predictions of Rainfall and Temperature Using GCM and ANN for Arid Regions: A Case Study for the Qassim Region, Saudi Arabia
by Khalid Alotaibi, Abdul Razzaq Ghumman, Husnain Haider, Yousry Mahmoud Ghazaw and Md. Shafiquzzaman
Water 2018, 10(9), 1260; https://doi.org/10.3390/w10091260 - 15 Sep 2018
Cited by 56 | Viewed by 7909
Abstract
Future predictions of rainfall patterns in water-scarce regions are highly important for effective water resource management. Global circulation models (GCMs) are commonly used to make such predictions, but these models are highly complex and expensive. Furthermore, their results are associated with uncertainties and [...] Read more.
Future predictions of rainfall patterns in water-scarce regions are highly important for effective water resource management. Global circulation models (GCMs) are commonly used to make such predictions, but these models are highly complex and expensive. Furthermore, their results are associated with uncertainties and variations for different GCMs for various greenhouse gas emission scenarios. Data-driven models including artificial neural networks (ANNs) and adaptive neuro fuzzy inference systems (ANFISs) can be used to predict long-term future changes in rainfall and temperature, which is a challenging task and has limitations including the impact of greenhouse gas emission scenarios. Therefore, in this research, results from various GCMs and data-driven models were investigated to study the changes in temperature and rainfall of the Qassim region in Saudi Arabia. Thirty years of monthly climatic data were used for trend analysis using Mann–Kendall test and simulating the changes in temperature and rainfall using three GCMs (namely, HADCM3, INCM3, and MPEH5) for the A1B, A2, and B1 emissions scenarios as well as two data-driven models (ANN: feed-forward-multilayer, perceptron and ANFIS) without the impact of any emissions scenario. The results of the GCM were downscaled for the Qassim region using the Long Ashton Research Station’s Weather Generator 5.5. The coefficient of determination (R2) and Akaike’s information criterion (AIC) were used to compare the performance of the models. Results showed that the ANNs could outperform the ANFIS for predicting long-term future temperature and rainfall with acceptable accuracy. All nine GCM predictions (three models with three emissions scenarios) differed significantly from one another. Overall, the future predictions showed that the temperatures of the Qassim region will increase with a specified pattern from 2011 to 2099, whereas the changes in rainfall will differ over various spans of the future. Full article
(This article belongs to the Section Water Resources Management, Policy and Governance)
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18 pages, 6783 KiB  
Article
Simulation of Runoff and Glacier Mass Balance and Sensitivity Analysis in a Glacierized Basin, North-Eastern Qinhai-Tibetan Plateau, China
by Xiaopeng Zhang, Xiang Qin, Chunhai Xu and Yushuo Liu
Water 2018, 10(9), 1259; https://doi.org/10.3390/w10091259 - 15 Sep 2018
Cited by 6 | Viewed by 4287
Abstract
Glaciers have been recognized as the most sensitive indicators of climate change. Mountainous areas, with their characteristic snow and glacier cover, have long been recognized as special hydrological environments, receiving above-average amounts of precipitation. The streams originating in the mountains, nourished with distinct [...] Read more.
Glaciers have been recognized as the most sensitive indicators of climate change. Mountainous areas, with their characteristic snow and glacier cover, have long been recognized as special hydrological environments, receiving above-average amounts of precipitation. The streams originating in the mountains, nourished with distinct seasonal variations, provide water for the populations of the adjacent lowland. Little is known about the effect of climate change on snow and glacier hydrology and glacier mass balance in the Laohugou Glacier Basin (LHGB) over the past 50 years. A study of the glacier basin was performed to quantify the expected impact of climate change on the hydrology in the north-eastern Qinghai-Tibet Plateau. The DEM (Digital Elevation Model) data, daily temperature, daily precipitation, and evaporation data were applied to force the HBV (Hydrologiska Byrans Vattenbalansavdelning)-light conceptual model to simulate runoff depth and glacier mass balance in the historical period (1959–2015). A genetic calibration algorithm approach (GAP method) was used to obtain parameter sets that reproduced observed runoff depth well. The results suggested a drastic increase of the runoff depth from 1995 to 2015 in the Laohugou glacier basin driven by increased temperature. Temperature and precipitation increased by 0.40 °C (10a)−1 and 1.6 mm·a−1 (p < 0.01), respectively, at AWS1 (the automatic weather station at 4192 m a.s.l. near the hydrological station) in the LHGB from 1959 to 2015. The simulated runoff depth increased at 5.7 mm·a−1 (p < 0.01), the glacier mass balance (GMB) of the LHGB was −280.5 mm·a−1, and the overall glacier mass balance was −17.55 m w.e. from 1959 to 2015. The runoff is found to be more sensitive to the variation of temperature than the variation of precipitation. When the glacier area is decreased by 10%, 53%, and 100%, the peak runoff (July) decreased by 20.4%, 54.2%, and 72.3% relative to the baseline, respectively. In the future climate, the function of glaciers in compensating a potential low flow and regulating peak flow will be weakened in the critical months. Full article
(This article belongs to the Section Hydrology)
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17 pages, 5446 KiB  
Article
Estimation of Precipitation Evolution from Desert to Oasis Using Information Entropy Theory: A Case Study in Tarim Basin of Northwestern China
by Xiangyang Zhou, Zhipan Niu and Wenjuan Lei
Water 2018, 10(9), 1258; https://doi.org/10.3390/w10091258 - 15 Sep 2018
Viewed by 4280
Abstract
The cold-wet effect of oasis improves the extreme natural conditions of the desert areas significantly. However, the relationship between precipitation and the width of oasis is challenged by the shortage of observed data. In this study, the evolution of annual precipitation from desert [...] Read more.
The cold-wet effect of oasis improves the extreme natural conditions of the desert areas significantly. However, the relationship between precipitation and the width of oasis is challenged by the shortage of observed data. In this study, the evolution of annual precipitation from desert to oasis was explored by the model establishment and simulation in Tarim Basin of northwestern China. The model was developed from the principle of maximum information entropy, and was calibrated by the China Meteorological Forcing Dataset with a high spatial resolution of 0.1° from 1990 to 2010. The model performs well in describing the evolution of annual precipitation from the desert to oasis when the oasis is wide enough, and the R2 is generally more than 0.90 and can be up to 0.99. However, it fails to simulate the seasonal precipitation evolution because of the non-convergence solved by nonlinear fitting and the unfixed upper boundary condition solved by the least square method. Through the simulation with the parameters obtained from the nonlinear fitting, the basic patterns, four stages of precipitation evolution with the oasis width increasing, are revealed at annual scale, and the current stages of these oases are also uncovered. Therefore, the establishment of the model and the simulated results provide a deeper insight from the perspective of informatics to understand the regional precipitation evolution of the desert–oasis system. These results are not only helpful in desertification prevention, but also helpful in fusing multisource data, especially in extreme drought desert areas. Full article
(This article belongs to the Special Issue Advances in Hydraulics and Hydroinformatics)
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15 pages, 2226 KiB  
Article
Formation of Palygorskite Clay from Treated Diatomite and its Application for the Removal of Heavy Metals from Aqueous Solution
by Houwaida Nefzi, Manef Abderrabba, Sameh Ayadi and Jalel Labidi
Water 2018, 10(9), 1257; https://doi.org/10.3390/w10091257 - 15 Sep 2018
Cited by 20 | Viewed by 5557
Abstract
Environmental contamination by toxic heavy metals is a serious worldwide phenomenon. Thus, their removal is a crucial issue. In this study, we found an efficient adsorbent to remove Cu2+ and Ni2+ from aqueous solution using two materials. Chemical modification was used [...] Read more.
Environmental contamination by toxic heavy metals is a serious worldwide phenomenon. Thus, their removal is a crucial issue. In this study, we found an efficient adsorbent to remove Cu2+ and Ni2+ from aqueous solution using two materials. Chemical modification was used to obtain palygorskite clay from diatomite. The adsorbents were characterized using X-ray florescence, Fourier transform infrared spectroscopy and X-ray diffraction. The effects of contact time, initial concentration, temperature and pH on the adsorption process were investigated. Our results showed that the (%) of maximum adsorption capacity of diatomite was 78.44% for Cu2+ at pH 4 and 77.3% for Ni2+ at pH 7, while the (%) of the maximum adsorption on palygorskite reached 91% for Cu2+ and 87.05% for Ni2+, in the same condition. The results indicate that the pseudo-second-order model can describe the adsorption process. Furthermore, the adsorption isotherms could be adopted by the Langmuir and the Freundlich models with good correlation coefficient (R2). Thus, our results showed that palygorskite prepared from Tunisian diatomite is a good adsorbent for the removal of heavy metals from water. Full article
(This article belongs to the Special Issue Water Pollution Control Using Clay Minerals and Agricultural Biomass-Based Adsorbents)
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20 pages, 18802 KiB  
Article
Assessing Slope Forest Effect on Flood Process Caused by a Short-Duration Storm in a Small Catchment
by Jingming Hou, Kaihua Guo, Feifei Liu, Hao Han, Qiuhua Liang, Yu Tong and Peng Li
Water 2018, 10(9), 1256; https://doi.org/10.3390/w10091256 - 15 Sep 2018
Cited by 17 | Viewed by 4936
Abstract
Land use has significant impact on the hydrologic and hydraulic processes in a catchment. This work applies a hydrodynamic based numerical model to quantitatively investigate the land use effect on the flood patterns under various rainfall and terrain conditions in an ideal V-shaped [...] Read more.
Land use has significant impact on the hydrologic and hydraulic processes in a catchment. This work applies a hydrodynamic based numerical model to quantitatively investigate the land use effect on the flood patterns under various rainfall and terrain conditions in an ideal V-shaped catchment and a realistic catchment, indicating the land use could considerably affect the rainfall-flood process and such effect varies with the catchment terrain, land use scenario and the rainfall events. The rainfall-flood process is less sensitive for the side slope than the channel slope. For a channel slope lower than the critical value in this work, the forest located in the middle of the catchment slope could most effectively attenuate the flood peak. When the channel slope is higher than the critical one, forest located in the downstream of the catchment could most significantly mitigate the peak discharge. Moreover, the attenuation effect becomes more obvious as the rainfall becomes heavier. The fragmentation of vegetation does not reduce the flood peak in a more obvious way, compared with the integral vegetation patterns with the same area proportion. The research can help more reasonably guide the land use plan related to flood risk. Full article
(This article belongs to the Section Water Resources Management, Policy and Governance)
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