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Special Issue "Adaptive Catchment Management and Reservoir Operation"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Water Resources Management and Governance".

Deadline for manuscript submissions: closed (31 July 2018)

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors

Guest Editor
Prof. Guangtao Fu

University of Exeter, Centre for Water Systems, Harrison Building, Exeter EX4 4QF, UK
Website | E-Mail
Interests: water resources management; flood risk analysis and management; system resilience analysis; smart water and wastewater; infrastructure systems; data and decision analytics
Guest Editor
Prof. Guangheng Ni

Tsinghua University, Department of Hydraulic Engineering, No. 1Qinghuayuan, Haidian, Beijing 100084, China
Website | E-Mail
Interests: distributed hydrological modeling; water–energy–ecosystem nexus; urban water and heat flux; transboundary waters
Guest Editor
Prof. Chi Zhang

Dalian University of Technology, School of Hydraulic Engineering Dalian 116023, China
Website | E-Mail
Interests: reservoir operation; water resources; flood risk management; adaptive catchment management

Special Issue Information

Dear Colleagues,

River catchments and reservoirs play a central role in water security, food supply, flood risk management, hydropower generation and ecosystem services; however, they are now under increasing pressure from population growth, economic activities and changing climate means and extremes in many parts of the world. Adaptive management of river catchments and reservoirs require an in-depth understanding of the impacts of future uncertainties and thus develop robust, sustainable solutions to meet the needs from various stakeholders and the environment. To tackle the huge challenges in moving towards adaptive catchment management, there is a need to review the latest developments in cutting-edge knowledge, novel methodologies, innovative technologies and case studies that are relative to catchment management and reservoir operation.

In this Special Issue, we invite researchers and practitioners to present the advances in adaptive river catchment management and reservoir operation in the face of uncertainty. The topics include, but are not limited to, innovative management frameworks, river catchment modelling, inflow forecasting, climate change impact, multi-objective reservoir operation, water-energy-ecosystem nexus, risk and resilience analysis, intervention strategies, new technologies, decision support tools, policy analysis and case studies.

Prof. Guangtao Fu
Prof. Guangheng Ni
Prof. Chi Zhang
Guest Editors

Manuscript Submission Information

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Keywords

  • adaptive management
  • catchment modelling
  • reservoir operation
  • risk analysis
  • water energy nexus

Published Papers (28 papers)

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Editorial

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Open AccessEditorial
Recent Advances in Adaptive Catchment Management and Reservoir Operation
Water 2019, 11(3), 427; https://doi.org/10.3390/w11030427
Received: 9 February 2019 / Revised: 22 February 2019 / Accepted: 25 February 2019 / Published: 27 February 2019
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Abstract
This editorial introduces the latest research advances in the special issue on catchment management and reservoir operations. River catchments and reservoirs play a central role in water security, community wellbeing and social-economic prosperity, but their operators and managers are under increasing pressures to [...] Read more.
This editorial introduces the latest research advances in the special issue on catchment management and reservoir operations. River catchments and reservoirs play a central role in water security, community wellbeing and social-economic prosperity, but their operators and managers are under increasing pressures to meet the challenges from population growth, economic activities and changing climates in many parts of the world. This challenge is tackled from various aspects in the 27 papers included in this special issue. A synthesis of these papers is provided, focusing on four themes: reservoir dynamics and impacts, optimal reservoir operation, climate change impacts, and integrated modelling and management. The contributions are discussed in the broader context of the field and future research directions are identified to achieve sustainable and resilient catchment management. Full article

Research

Jump to: Editorial

Open AccessArticle
Relationships Among Animal Communities, Lentic Habitats, and Channel Characteristics for Ecological Sediment Management
Water 2018, 10(10), 1479; https://doi.org/10.3390/w10101479
Received: 29 August 2018 / Revised: 15 October 2018 / Accepted: 16 October 2018 / Published: 19 October 2018
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Abstract
This study used a multiscale analysis of relationships among the bitterling and mussel communities, lentic habitat structures with conditions and flooding frequency, and channel characteristics for application in ecological sediment management. From the Kizu River in Japan, 120 lentic habitats were sampled in [...] Read more.
This study used a multiscale analysis of relationships among the bitterling and mussel communities, lentic habitat structures with conditions and flooding frequency, and channel characteristics for application in ecological sediment management. From the Kizu River in Japan, 120 lentic habitats were sampled in 2007 and 2010. The floodplain vertical shape index (FVSI), which indicates the degree of convexity or concavity of the vertical shape of a floodplain, was used as channel characteristics using historical cross-section profiles obtained from 1960 to 2012. For examining the relationships between bitterlings/mussels and each habitat condition or structure, abundance values of bitterlings and mussels were transformed into habitat suitability index (HSI). Furthermore, the relationships between the number of habitat structures and FVSI were analyzed. The results indicated that bitterlings and mussels are more abundant in terrace ponds than in active ponds, especially so in terrace ponds located in the lower area of bars with a flooding frequency of 8–16 days/year (bitterlings), those located in the lower area of bars with a flooding frequency of 8 days/year, and those located in the upper area of bars with a flooding frequency of 16–22 days/year (mussels). These ponds tended to have less than 1 cm mud depth that was negatively related to abundance of mussels. These suitable habitat types tended to be located in channels with a floodplain vertical shape index between −0.35 and 0.05. We established countermeasures to prevent channel types with floodplain vertical shape index exceeding 0.05 instead of restoring the previous channel conditions. Full article
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Open AccessArticle
Season-Dependent Hedging Policies for Reservoir Operation—A Comparison Study
Water 2018, 10(10), 1311; https://doi.org/10.3390/w10101311
Received: 20 July 2018 / Revised: 15 September 2018 / Accepted: 16 September 2018 / Published: 22 September 2018
Cited by 2 | PDF Full-text (6430 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
During periods of significant water shortage or when drought is impending, it is customary to implement some kind of water supply reduction measures with a view to prevent the occurrence of severe shortages (vulnerability) in the near future. In the case of operation [...] Read more.
During periods of significant water shortage or when drought is impending, it is customary to implement some kind of water supply reduction measures with a view to prevent the occurrence of severe shortages (vulnerability) in the near future. In the case of operation of a water supply reservoir, this reduction of water supply is affected by hedging schemes or hedging policies. This research work aims to compare the popular hedging policies: (i) linear two-point hedging; (ii) modified two-point hedging; and, (iii) discrete hedging based on time-varying and constant hedging parameters. A parameterization-simulation-optimization (PSO) framework is employed for the selection of the parameters of the compromising hedging policies. The multi-objective evolutionary search-based technique (Non-dominated Sorting based Genetic Algorithm-II) was used to identify the Pareto-optimal front of hedging policies that seek to obtain the trade-off between shortage ratio and vulnerability. The case example used for illustration is the Hemavathy reservoir in Karnataka, India. It is observed that the Pareto-optimal front that was obtained from time-varying hedging policies show significant improvement in reservoir performance when compared to constant hedging policies. The variation in the monthly parameters of the time-variant hedging policies shows a strong correlation with monthly inflows and available water. Full article
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Open AccessArticle
Optimal Operation of Cascade Reservoirs for Flood Control of Multiple Areas Downstream: A Case Study in the Upper Yangtze River Basin
Water 2018, 10(9), 1250; https://doi.org/10.3390/w10091250
Received: 20 June 2018 / Revised: 1 September 2018 / Accepted: 11 September 2018 / Published: 14 September 2018
Cited by 3 | PDF Full-text (2563 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of a flood control reservoir operation is to prevent flood damage downstream of the reservoir and the safety of the reservoir itself. When a single reservoir cannot provide enough storage capacity for certain flood control points downstream, cascade reservoirs should be [...] Read more.
The purpose of a flood control reservoir operation is to prevent flood damage downstream of the reservoir and the safety of the reservoir itself. When a single reservoir cannot provide enough storage capacity for certain flood control points downstream, cascade reservoirs should be operated together to protect these areas from flooding. In this study, for efficient use of the reservoir storage, an optimal flood control operation model of cascade reservoirs for certain flood control points downstream was proposed. In the proposed model, the upstream reservoirs with the optimal operation strategy were considered to reduce the inflow of the reservoir downstream. For a large river basin, the flood routing and time-lag cannot be neglected. So, dynamic programming (DP) combined with the progressive optimality algorithm (POA) method, DP-POA, was proposed. Thus, the innovation of this study is to propose a two-stage optimal reservoir operation model with a DP-POA algorithm to solve the problem of optimal co-operation of cascade reservoirs for multiple flood control points downstream during the flood season. The upper Yangtze River was selected as a case study. Three reservoirs from upstream to downstream, Xiluodu, Xiangjiaba and the Three Gorges reservoirs (TGR) in the upper Yangtze River, were taken into account. Results demonstrate that the two-stage optimization algorithm has a good performance in solving the cascade reservoirs optimization problem, because the inflow of reservoir downstream and the division volumes were largely reduced. After the optimal operation of Xiluodu and Xiangjiaba reservoirs, the average reduction of flood peak for all these 13 typical flood hydrographs (TFHs) is 13.6%. Meanwhile, the cascade reservoirs can also store much more storm water during a flood event, and the maximum volumes stored in those two reservoirs upstream in this study can reach 25.2 billion m3 during a flood event. Comprising the proposed method with the current operation method, results demonstrate that the flood diversion volumes at the flood control points along the river decrease significantly. Full article
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Open AccessArticle
Water Resource Optimal Allocation Based on Multi-Agent Game Theory of HanJiang River Basin
Water 2018, 10(9), 1184; https://doi.org/10.3390/w10091184
Received: 27 July 2018 / Revised: 23 August 2018 / Accepted: 28 August 2018 / Published: 4 September 2018
Cited by 4 | PDF Full-text (1467 KB) | HTML Full-text | XML Full-text
Abstract
Water scarcity is an important issue in many countries, and it is therefore necessary to improve the efficiency and equality of water resource allocation for decision makers. Based on game theory (GT), a bi-level optimization model is developed from the perspective of a [...] Read more.
Water scarcity is an important issue in many countries, and it is therefore necessary to improve the efficiency and equality of water resource allocation for decision makers. Based on game theory (GT), a bi-level optimization model is developed from the perspective of a leader-follower relationship among agents (stakeholders) of a river basin in this study, which consists of a single-agent GT-based optimization model of common interest and a multi-agent cooperative GT-based model. The Hanjiang River Basin is chosen as a case study, where there are conflicts among different interest agents in this basin. The results show that the proposed bi-level model could attain the same improvement of common interest by 8%, with the conventional optimal model. However, different from the conventional optimal model, since the individual interests have been considered in the bi-level optimization model, the willingness of cooperation of individuals has risen from 20% to 80%. With a slight decrease by 3% of only one agent, the increases of interest of other agents are 14%, 18%, 7%, and 14%, respectively, when using the bi-level optimization model. The conclusion could be drawn that the proposed model is superior to the conventional optimal model. Moreover, this study provides scientific support for the large spatial scale water resource allocation model. Full article
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Open AccessArticle
Multi-Objective Optimization of Resilient Design of the Multipurpose Reservoir in Conditions of Uncertain Climate Change
Water 2018, 10(9), 1110; https://doi.org/10.3390/w10091110
Received: 18 June 2018 / Revised: 14 August 2018 / Accepted: 16 August 2018 / Published: 21 August 2018
Cited by 1 | PDF Full-text (3045 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents and assesses a new approach to decision-making methods for the design of new reservoirs due in times of decreasing water resources. The methods used in this case are decision theory, Resilience and Robustness method. The methods have been selected primarily [...] Read more.
This paper presents and assesses a new approach to decision-making methods for the design of new reservoirs due in times of decreasing water resources. The methods used in this case are decision theory, Resilience and Robustness method. The methods have been selected primarily to analyze different design parameters of a new dam, mainly dam heights leading to different reservoir volumes. The study presents a novel approach to the optimal design of a multipurpose reservoir that would provide enough water for downstream environmental flow, residential and industrial water supply, agricultural water supply, and hydropower generation in the current conditions of climate uncertainty. Uncertainties are interpreted as possible future changes in the climate system using outputs from regional climatic models. In the case study, a simulation model was developed which is able to quantify long-term water balance and use this data to quantify resilience and robustness of its water supply. The simulation model was correlated to the GANetXL software in order to perform Genetic Algorithms based optimization of the reservoir’s operation. The simulation–optimization model was then applied to a real-life case study in the Czech Republic, in the Morava River Basin where a new dam with the multipurpose reservoir is planned to be built in the future. The results obtained in this way were analyzed in detail to identify the overall best solution consist of dam height and the total reservoir monthly outflow and new operational rules for the analyzed multipurpose reservoir. Full article
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Open AccessArticle
Joint Operation of Surface Water and Groundwater Reservoirs to Address Water Conflicts in Arid Regions: An Integrated Modeling Study
Water 2018, 10(8), 1105; https://doi.org/10.3390/w10081105
Received: 31 July 2018 / Revised: 17 August 2018 / Accepted: 17 August 2018 / Published: 19 August 2018
Cited by 4 | PDF Full-text (6454 KB) | HTML Full-text | XML Full-text
Abstract
At the basin scale, the operation of surface water reservoirs rarely takes groundwater aquifers into consideration, which can also be regarded as reservoirs underground. This study investigates the impact of reservoir operation on the water cycle and evaluates the effect of the joint [...] Read more.
At the basin scale, the operation of surface water reservoirs rarely takes groundwater aquifers into consideration, which can also be regarded as reservoirs underground. This study investigates the impact of reservoir operation on the water cycle and evaluates the effect of the joint operation of surface water and groundwater reservoirs on the water conflict in arid regions through an integrated modeling approach. The Heihe River Basin (HRB) in northwestern China is selected as the study area. Our results show that the ecological operational strategies of a reservoir under construction in the upper HRB have a direct impact on the agricultural water uses and consequently affect other hydrological processes. The ecological operation strategy with a smaller water release and a longer duration is beneficial to securing the environmental flow towards the downstream area and to replenishing aquifers. With the joint operation of surface water and groundwater reservoirs, a balance among the agriculture water need, the groundwater sustainability in the Middle HRB and the ecological water need in the Lower HRB can be flexibly achieved. However, the joint operation can hardly improve the three aspects simultaneously. To resolve the water conflict in HRB, additional engineering and/or policy measures are desired. Full article
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Open AccessArticle
Inherent Relationship between Flow Duration Curves at Different Time Scales: A Perspective on Monthly Flow Data Utilization in Daily Flow Duration Curve Estimation
Water 2018, 10(8), 1008; https://doi.org/10.3390/w10081008
Received: 12 June 2018 / Revised: 17 July 2018 / Accepted: 24 July 2018 / Published: 30 July 2018
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Abstract
Modelling flow duration curves (FDCs) has long been a topic of interest since it is widely used in various hydrological applications. Most studies related to the estimation of FDCs in ungauged or partial gauged basins focus primarily on using climate and catchment characteristics [...] Read more.
Modelling flow duration curves (FDCs) has long been a topic of interest since it is widely used in various hydrological applications. Most studies related to the estimation of FDCs in ungauged or partial gauged basins focus primarily on using climate and catchment characteristics to regionalize FDC at some single time scale. However, the relationship of FDCs at various time scales are rarely analyzed or studied. Here, we propose two methods, which are Modelled FDC Parameter comparison (M-FDC-P) and Empirical FDC Ratio comparison (E-FDC-R), to study the quantitative relationship between daily and monthly FDCs. One method M-FDC-P, selects a Kappa (KAP) distribution to represent the characteristics of the FDCs and then analyzes the relationship between KAP parameters of modelled FDCs at different time scales. Results indicate that three out of four parameters have strong correlations between FDCs at daily and monthly time scales. The other method, E-FDC-R, compares the quantitative relationship between daily and monthly empirical FDCs with given exceedance probabilities. The Power function is used for fitting the ratio-exceedance probability curves. In addition, the simulated daily FDC derived from monthly FDC can be very consistent with the observed daily flow records when the two parameters of power function are quantified precisely. These results clearly indicate that there are strong connections between daily and monthly FDCs, and monthly FDC can provide valuable information for daily FDC estimation. Since flow records at a large time scale are easier to obtain, daily FDC could be derived from monthly FDC by considering the inherent relationships between FDCs at different time scales, which is not sufficiently realized in previous studies. Full article
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Open AccessFeature PaperArticle
Heating Impact of a Tropical Reservoir on Downstream Water Temperature: A Case Study of the Jinghong Dam on the Lancang River
Water 2018, 10(7), 951; https://doi.org/10.3390/w10070951
Received: 1 June 2018 / Revised: 5 July 2018 / Accepted: 11 July 2018 / Published: 17 July 2018
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Abstract
Reservoirs change downstream thermal regimes by releasing water of different temperatures to that under natural conditions, which may then alter downstream biodiversity and ecological processes. The hydropower exploitation in the mainstream Lancang-Mekong River has triggered concern for its potential effects on downstream countries, [...] Read more.
Reservoirs change downstream thermal regimes by releasing water of different temperatures to that under natural conditions, which may then alter downstream biodiversity and ecological processes. The hydropower exploitation in the mainstream Lancang-Mekong River has triggered concern for its potential effects on downstream countries, especially the impact of the released cold water on local fishery production. However, it was observed recently that the annual water temperature downstream of the Jinghong Reservoir (near the Chinese border) has increased by 3.0 °C compared to its historical average (1997–2004). In this study, a three-dimensional (3D) model of the Jinghong Reservoir was established to simulate its hydro- and thermodynamics. Results show that: (1) the impoundment of the Jinghong Reservoir contributed about 1.3 °C to the increment of the water temperature; (2) the solar radiation played a much more important role in comparison with atmosphere-water heat exchange in changing water temperatures; and (3) the outflow rate also imposed a significant influence on the water temperature by regulating the residence time. After impoundment, the residence time increased from 3 days to 11 days, which means that the duration that the water body can absorb solar radiation has been prolonged. The results explain the heating mechanism of the Jinghong Reservoir brought to downstream water temperatures. Full article
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Open AccessArticle
Simulating the Evolution of the Land and Water Resource System under Different Climates in Heilongjiang Province, China
Water 2018, 10(7), 868; https://doi.org/10.3390/w10070868
Received: 11 May 2018 / Revised: 26 June 2018 / Accepted: 26 June 2018 / Published: 29 June 2018
Cited by 1 | PDF Full-text (2291 KB) | HTML Full-text | XML Full-text
Abstract
Heilongjiang Province is under the pressure of a water shortage due to climate change, population growth and economic development. To effectively manage regional land and water resources, this paper describes a system dynamics model that was built to simulate the interaction between land [...] Read more.
Heilongjiang Province is under the pressure of a water shortage due to climate change, population growth and economic development. To effectively manage regional land and water resources, this paper describes a system dynamics model that was built to simulate the interaction between land and water resources and socioeconomic factors, as well as the evolution of regional land and water resources in different climates in Heilongjiang Province. The results show that the declining trend of unused land area and the water supply–demand ratio will not stop, even under the most optimistic (e.g., humid climate) climate conditions, if the current land use patterns continue. Therefore, measures should be taken to manage the unreasonable usage patterns of land and water resources in this region. This study simulated the evolution of regional land and water resources for five scenarios under an arid climate by changing the net irrigation quota for paddy fields, the water quota for industrial use, forestland area, annual change rate of farmland area, and the growth rate of the gross industrial output value. Further, a combined scenario that can maximally reduce the regional land and water resource sustainable risk was identified. The simulation of the combined scenario showed that it can effectively increase the degree of regional land and water resource use in the region, as well as reduce the risks that threaten these resources. This study provides theoretical support for the efficient use of land and water resources in the future. Full article
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Open AccessArticle
Piecewise-Linear Hedging Rules for Reservoir Operation with Economic and Ecologic Objectives
Water 2018, 10(7), 865; https://doi.org/10.3390/w10070865
Received: 10 May 2018 / Revised: 24 June 2018 / Accepted: 25 June 2018 / Published: 29 June 2018
Cited by 3 | PDF Full-text (2979 KB) | HTML Full-text | XML Full-text
Abstract
The construction of dams and operation of reservoirs have a significant impact on the interruption of aquatic and riparian ecological systems, by altering natural stream flows in river courses. Recently, the ecological requirements are included as an additional objective in reservoir operation in [...] Read more.
The construction of dams and operation of reservoirs have a significant impact on the interruption of aquatic and riparian ecological systems, by altering natural stream flows in river courses. Recently, the ecological requirements are included as an additional objective in reservoir operation in order to restore the natural stream flows and reduce the negative impacts of reservoir operations on ecosystems that rely on the natural flows. The key challenge involving ecological requirements is to balance the ecological and economic objectives by operation rules, on the basis of quantitatively identifying the objective of ecological flows required to maintain the natural flow regime for ecosystem. This study develops a piecewise-linear multi-objective hedging rule (PMHR) for reservoir operations, with ecologic flow objectives represented by 33 hydrologic parameters from the indicators of hydrologic alteration (IHA). Variables of the PMHR are obtained through optimization using a vector evaluated genetic algorithm. The results show that the PMHR improves the ecological water releases without reducing economic water supplies in the case river in the context of hydrological uncertainty. It can offer technological references for improving the utility of water resource management under competitive conditions of water resources. Full article
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Open AccessArticle
Watershed Sediment and Its Effect on Storage Capacity: Case Study of Dokan Dam Reservoir
Water 2018, 10(7), 858; https://doi.org/10.3390/w10070858
Received: 28 May 2018 / Revised: 19 June 2018 / Accepted: 26 June 2018 / Published: 28 June 2018
Cited by 3 | PDF Full-text (1968 KB) | HTML Full-text | XML Full-text
Abstract
Dokan is a multipurpose dam located on the Lesser Zab River in the Iraq/Kurdistan region. The dam has operated since 1959, and it drains an area of 11,690 km2. All reservoirs in the world suffer from sediment deposition. It is one [...] Read more.
Dokan is a multipurpose dam located on the Lesser Zab River in the Iraq/Kurdistan region. The dam has operated since 1959, and it drains an area of 11,690 km2. All reservoirs in the world suffer from sediment deposition. It is one of the main problems for reservoir life sustainability. Sustainable reservoir sediment-management practices enable the reservoir to function for a longer period of time by reducing reservoir sedimentation. This study aims to assess the annual runoff and sediment loads of the Dokan Dam watershed using the soil and water assessment tool (SWAT) model to evaluate the relative contributions in comparison with the total values delivered from both watershed and Lesser Zab River and to identify the basins with a high sediment load per unit area. These help in the process of developing a plan and strategy to manage sediment inflow and deposition. The SUFI-2 program was applied for a model calibrated based on the available field measurements of the adjacent Derbendekhan Dam watershed, which has similar geological formations, characteristics and weather. For the calibration period (1961–1968), the considered statistical criteria of determination coefficients and Nash–Sutcliffe model efficiency were 0.75 and 0.64 for runoff while the coefficients were 0.65 and 0.63 for sediment load, respectively. The regionalization technique for parameter transformation from Derbendekhan to Dokan watershed was applied. Furthermore, the model was validated based on transformed parameters and the available observed flow at the Dokan watershed for the period (1961–1964); they gave reasonable results for the determination coefficients and Nash–Sutcliffe model efficiency, which were 0.68 and 0.64, respectively. The results of SWAT project simulation for Dokan watershed for the period (1959–2014) indicated that the average annual runoff volume which entered the reservoir was about 2100 million cubic meters (MCM). The total sediment delivered to the reservoir was about 72 MCM over the 56 years of dam life, which is equivalent to 10% of the reservoir dead storage. Two regression formulas were presented to correlate the annual runoff volume and sediment load with annual rain depth for the studied area. In addition, a spatial distribution of average annual sediment load was constructed to identify the sub basin of the high contribution of sediment load. Full article
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Open AccessArticle
Research on Cascade Reservoirs’ Short-Term Optimal Operation under the Effect of Reverse Regulation
Water 2018, 10(6), 808; https://doi.org/10.3390/w10060808
Received: 7 May 2018 / Revised: 2 June 2018 / Accepted: 4 June 2018 / Published: 19 June 2018
Cited by 3 | PDF Full-text (3122 KB) | HTML Full-text | XML Full-text
Abstract
Currently research on joint operation of a large reservoir and its re-regulating reservoir focuses on either water quantity regulation or water head regulation. The accuracy of relevant models is in need of improvement if the influence of factors such as water flow hysteresis [...] Read more.
Currently research on joint operation of a large reservoir and its re-regulating reservoir focuses on either water quantity regulation or water head regulation. The accuracy of relevant models is in need of improvement if the influence of factors such as water flow hysteresis and the aftereffect of tail water level variation are taken into consideration. In this paper, given the actual production of Pankou-Xiaoxuan cascade hydropower stations that combines two operation modes (‘electricity to water’ and ‘water to electricity’), a coupling model of their short-term optimal operation is developed, which considers Xiaoxuan reservoir’s regulating effect on Pankou reservoir’s outflow volume and water head. Factors such as water flow hysteresis and the aftereffect of tail water level variation are also considered to enhance the model’s accuracy. The Backward Propagation (BP) neural network is employed for precise calculation of the downstream reservoir’s inflow and the upstream reservoir’s tail water level. Besides, we put forth Accompanying Progressive Optimality Algorithm (APOA) to solve the coupling model with aftereffect. An example is given to verify the scientificity of the proposed model and the advantages of APOA. Through analysis of the model calculation results, the optimal operation rules of the cascade reservoirs are obtained in terms of water quantity regulation and water head regulation, which can provide scientific reference for cascade reservoirs’ optimal operation. Full article
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Open AccessFeature PaperArticle
Quantification of Seasonal Precipitation over the upper Chao Phraya River Basin in the Past Fifty Years Based on Monsoon and El Niño/Southern Oscillation Related Climate Indices
Water 2018, 10(6), 800; https://doi.org/10.3390/w10060800
Received: 29 April 2018 / Revised: 1 June 2018 / Accepted: 13 June 2018 / Published: 17 June 2018
Cited by 1 | PDF Full-text (4309 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
For better water resources management, we proposed a method to estimate basin-scale seasonal rainfall over selected areas of the Chao Phraya River Basin, Thailand, from existing climate indices that represent variations in the Asian summer monsoon, the El Niño/Southern Oscillation, and sea surface [...] Read more.
For better water resources management, we proposed a method to estimate basin-scale seasonal rainfall over selected areas of the Chao Phraya River Basin, Thailand, from existing climate indices that represent variations in the Asian summer monsoon, the El Niño/Southern Oscillation, and sea surface temperatures (SST) in the Pacific Ocean. The basin-scale seasonal rainfall between 1965 and 2015 was calculated for the upper Ping River Basin (PRB) and the upper Nan River Basin (NRB) from a gridded rainfall dataset and rainfall data collected at several gauging stations. The corresponding climate indices, i.e., the Equatorial-Southern Oscillation Index (EQ-SOI), Indian Monsoon Index (IMI), and SST-related indices, were examined to quantify seasonal rainfall. Based on variations in the rainfall anomaly and each climate index, we found that IMI is the primary variable that can explain variations in seasonal rainfall when EQ-SOI is negative. Through a multiple regression analysis, we found that EQ-SOI and two SST-related indices, i.e., Pacific Decadal Oscillation Index (PDO) and SST anomalies in the tropical western Pacific (SSTNW), can quantify the seasonal rainfall for years with positive EQ-SOI. The seasonal rainfall calculated for 1975 to 2015 based on the proposed method was highly correlated with the observed rainfall, with correlation coefficients of 0.8 and 0.86 for PRB and NRB, respectively. These results suggest that the existing indices are useful for quantifying basin-scale seasonal rainfall, provided a proper classification and combination of the climate indices are introduced. The developed method could forecast seasonal rainfall over the target basins if well-forecasted climate indices are provided with sufficient leading time. Full article
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Open AccessArticle
An Integrated Method for Accounting for Water Environmental Capacity of the River–Reservoir Combination System
Water 2018, 10(4), 483; https://doi.org/10.3390/w10040483
Received: 31 January 2018 / Revised: 26 March 2018 / Accepted: 11 April 2018 / Published: 14 April 2018
Cited by 3 | PDF Full-text (35538 KB) | HTML Full-text | XML Full-text
Abstract
The security of drinking water is a serious issue in China and worldwide. As the backup source of drinking water for the Changde City in China, the Huangshi Reservoir suffers from the threat of eutrophication due to the water quality of the reservoir [...] Read more.
The security of drinking water is a serious issue in China and worldwide. As the backup source of drinking water for the Changde City in China, the Huangshi Reservoir suffers from the threat of eutrophication due to the water quality of the reservoir ecosystem being affected by the tributaries that carry Non-Point Source (NPS) pollutants. The calculation of the water environmental capacity (WEC) can provide a scientific basis for water pollution control, which refers to the maximum amount of pollutants that the water can accommodate. In this paper, according to the hydrological characteristics of the river–reservoir combination system, a one-dimensional (1-D) water quality model and the Environmental Fluid Dynamics Code (EFDC) model were chosen to calculate the water environmental capacity of each functional zone in this basin. The quantity control of pollution from the tributaries was conducted based on the combined results of the water environmental capacity calculation from the EFDC model and a one-dimensional (1-D) river water quality model. The results show that total water environmental capacity of the tributaries included a chemical oxygen demand (COD) of 421.97 tons; ammonia nitrogen (NH3-N) of 40.99 tons; total nitrogen (TN) of 35.94 tons; and total phosphorus (TP) of 9.54 tons. The water environmental capacity of the Huangshi Reservoir region accounts for more than 93% of the total capacity. The reduction targets of the major pollutants in the Huangshi Reservoir and its four major input rivers, which are, namely, the Bamao River, the Longtan River, the Fanjiafang River, and the Dongtan River, have been determined to achieve the water quality objectives for the reservoir in 2020 and 2025. The results will be helpful for the local water quality management and will provide a valuable example for other similar water source reservoirs. Full article
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Open AccessArticle
Long-Term Scheduling of Large-Scale Cascade Hydropower Stations Using Improved Differential Evolution Algorithm
Water 2018, 10(4), 383; https://doi.org/10.3390/w10040383
Received: 1 March 2018 / Revised: 18 March 2018 / Accepted: 20 March 2018 / Published: 26 March 2018
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Abstract
Long-term scheduling of large cascade hydropower stations (LSLCHS) is a complex problem of high dimension, nonlinearity, coupling and complex constraint. In view of the above problem, we present an improved differential evolution (iLSHADE) algorithm based on LSHADE, a state-of-the-art evolutionary algorithm. iLSHADE uses [...] Read more.
Long-term scheduling of large cascade hydropower stations (LSLCHS) is a complex problem of high dimension, nonlinearity, coupling and complex constraint. In view of the above problem, we present an improved differential evolution (iLSHADE) algorithm based on LSHADE, a state-of-the-art evolutionary algorithm. iLSHADE uses new mutation strategies “current to pbest/2-rand” to obtain wider search range and accelerate convergence with the preventing individual repeated failure evolution (PIRFE) strategy. The handling of complicated constraints strategy of ε-constrained method is presented to handle outflow, water level and output constraints in the cascade reservoir operation. Numerical experiments of 10 benchmark functions have been done, showing that iLSHADE has stable convergence and high efficiency. Furthermore, we demonstrate the performance of the iLSHADE algorithm by comparing it with other improved differential evolution algorithms for LSLCHS in four large hydropower stations of the Jinsha River. With the applications of iLSHADE in reservoir operation, LSLCHS can obtain more power generation benefit than other alternatives in dry, normal, and wet years. The results of numerical experiments and case studies show that the iLSHADE has a distinct optimization effect and good stability, and it is a valid and reliable tool to solve LSLCHS problem. Full article
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Open AccessArticle
Real-Time Flood Control by Tree-Based Model Predictive Control Including Forecast Uncertainty: A Case Study Reservoir in Turkey
Water 2018, 10(3), 340; https://doi.org/10.3390/w10030340
Received: 18 December 2017 / Revised: 8 March 2018 / Accepted: 9 March 2018 / Published: 19 March 2018
Cited by 4 | PDF Full-text (7195 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Optimal control of reservoirs is a challenging task due to conflicting objectives, complex system structure, and uncertainties in the system. Real time control decisions suffer from streamflow forecast uncertainty. This study aims to use Probabilistic Streamflow Forecasts (PSFs) having a lead-time up to [...] Read more.
Optimal control of reservoirs is a challenging task due to conflicting objectives, complex system structure, and uncertainties in the system. Real time control decisions suffer from streamflow forecast uncertainty. This study aims to use Probabilistic Streamflow Forecasts (PSFs) having a lead-time up to 48 h as input for the recurrent reservoir operation problem. A related technique for decision making is multi-stage stochastic optimization using scenario trees, referred to as Tree-based Model Predictive Control (TB-MPC). Deterministic Streamflow Forecasts (DSFs) are provided by applying random perturbations on perfect data. PSFs are synthetically generated from DSFs by a new approach which explicitly presents dynamic uncertainty evolution. We assessed different variables in the generation of stochasticity and compared the results using different scenarios. The developed real-time hourly flood control was applied to a test case which had limited reservoir storage and restricted downstream condition. According to hindcasting closed-loop experiment results, TB-MPC outperforms the deterministic counterpart in terms of decreased downstream flood risk according to different independent forecast scenarios. TB-MPC was also tested considering different number of tree branches, forecast horizons, and different inflow conditions. We conclude that using synthetic PSFs in TB-MPC can provide more robust solutions against forecast uncertainty by resolution of uncertainty in trees. Full article
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Open AccessArticle
Evaluating Regime Change of Sediment Transport in the Jingjiang River Reach, Yangtze River, China
Water 2018, 10(3), 329; https://doi.org/10.3390/w10030329
Received: 6 February 2018 / Revised: 6 March 2018 / Accepted: 14 March 2018 / Published: 15 March 2018
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Abstract
The sediment regime in the Jingjiang river reach of the middle Yangtze River has been significantly changed from quasi-equilibrium to unsaturated since the impoundment of the Three Gorges Dam (TGD). Vertical profiles of suspended sediment concentration (SSC) and sediment flux can be adopted [...] Read more.
The sediment regime in the Jingjiang river reach of the middle Yangtze River has been significantly changed from quasi-equilibrium to unsaturated since the impoundment of the Three Gorges Dam (TGD). Vertical profiles of suspended sediment concentration (SSC) and sediment flux can be adopted to evaluate the sediment regime at the local and reach scale, respectively. However, the connection between the vertical concentration profiles and the hydrologic conditions of the sub-saturated channel has rarely been examined based on field data. Thus, vertical concentration data at three hydrological stations in the reach (Zhicheng, Shashi, and Jianli) are collected. Analyses show that the near-bed concentration (within 10% of water depth from the riverbed) may reach up to 15 times that of the vertical average concentration. By comparing the fractions of the suspended sediment and bed material before and after TGD operation, the geomorphic condition under which the distinct large near-bed concentrations occur have been examined. Based on daily discharge-sediment hydrographs, the reach scale sediment regime and availability of sediment sources are analyzed. In total, remarkable large near-bed concentrations may respond to the combination of wide grading suspended particles and bed material. Finally, several future challenges caused by the anomalous vertical concentration profiles in the unsaturated reach are discussed. This indicates that more detailed measurements or new measuring technologies may help us to provide accurate measurements, while a fractional dispersion equation may help us in describing. The present study aims to gain new insights into regime change of sediment suspension in the river reaches downstream of a very large reservoir. Full article
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Open AccessArticle
Sensitivity Analysis for the Inverted Siphon in a Long Distance Water Transfer Project: An Integrated System Modeling Perspective
Water 2018, 10(3), 292; https://doi.org/10.3390/w10030292
Received: 3 February 2018 / Revised: 5 March 2018 / Accepted: 6 March 2018 / Published: 8 March 2018
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Abstract
Long distance water diversion projects are developed to alleviate the conflicts between supply and demand of water resources across different watersheds. However, the significant scale water diversion projects bring new challenges for the water supply security. This paper presents the flood risk of [...] Read more.
Long distance water diversion projects are developed to alleviate the conflicts between supply and demand of water resources across different watersheds. However, the significant scale water diversion projects bring new challenges for the water supply security. This paper presents the flood risk of inverted siphon structure which is used for crossing transversally in the water diversion project through sensitivity analysis. Soboĺ and regionalized sensitivity analysis are used to investigate the sensitive parameters of the integrated model and the sensitive range of the parameters, respectively. The integrated system model consists of the hydrologic model, the sediment transport model and the siphon hydraulic model to determine the flood overtopping duration and volume, which are used to quantify flood risk in this study. The flood overtopping duration and volume indicators are used to quantify flood risk in the sensitivity analysis. The South to North Water Diversion Project in China is used as a case study. The results show the mean rainfall and roughness coefficient of the pipe are the most sensitive parameters in the integrated models, while the sensitive range of these two parameters are distinct. The sensitivity analysis of the inverted siphon provides an insight into the significant contributions to the flood risk. The analysis can provide the guidance for the system operation security. Full article
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Open AccessArticle
Optimal Operation of Hydropower Reservoirs under Climate Change: The Case of Tekeze Reservoir, Eastern Nile
Water 2018, 10(3), 273; https://doi.org/10.3390/w10030273
Received: 3 January 2018 / Revised: 25 February 2018 / Accepted: 27 February 2018 / Published: 5 March 2018
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Abstract
Optimal operation of reservoirs is very essential for water resource planning and management, but it is very challenging and complicated when dealing with climate change impacts. The objective of this paper was to assess existing and future hydropower operation at the Tekeze reservoir [...] Read more.
Optimal operation of reservoirs is very essential for water resource planning and management, but it is very challenging and complicated when dealing with climate change impacts. The objective of this paper was to assess existing and future hydropower operation at the Tekeze reservoir in the face of climate change. In this study, a calibrated and validated Soil and Water Assessment Tool (SWAT) was used to model runoff inflow into the Tekeze hydropower reservoir under present and future climate scenarios. Inflow to the reservoir was simulated using hydro-climatic data from an ensemble of downscaled climate data based on the Coordinated Regional climate Downscaling Experiment over African domain (CORDEX-Africa) with Coupled Intercomparison Project Phase 5 (CMIP5) simulations under Representative Concentration Pathway (RCP)4.5 and RCP8.5 climate scenarios. Observed and projected inflows to Tekeze hydropower reservoir were used as input to the US Army Corps of Engineer’s Reservoir Evaluation System Perspective Reservoir Model (HEC-ResPRM), a reservoir operation model, to optimize hydropower reservoir release, storage and pool level. Results indicated that climate change has a clear impact on reservoir inflow and showed increase in annual and monthly inflow into the reservoir except in dry months from May to June under RCP4.5 and RCP8.5 climate scenarios. HEC-ResPRM optimal operation results showed an increase in Tekeze reservoir power storage potential up to 25% and 30% under RCP4.5 and RCP8.5 climate scenarios, respectively. This implies that Tekeze hydropower production will be affected by climate change. This analysis can be used by water resources planners and mangers to develop reservoir operation techniques considering climate change impact to increase power production. Full article
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Open AccessArticle
Decline of N and P Uptake in the Inner Protection Zone of a Terminal Reservoir during Inter-Basin Water Transfers
Water 2018, 10(2), 178; https://doi.org/10.3390/w10020178
Received: 23 December 2017 / Revised: 1 February 2018 / Accepted: 6 February 2018 / Published: 9 February 2018
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Abstract
Inter-basin water transfer projects are designed to relieve water scarcity around the world. However, ecological problems relating to reductions in protection zone functions can occur during inter-basin transfers. This paper uses the largest inter-basin water transfer project in the world, namely, the South-to-North [...] Read more.
Inter-basin water transfer projects are designed to relieve water scarcity around the world. However, ecological problems relating to reductions in protection zone functions can occur during inter-basin transfers. This paper uses the largest inter-basin water transfer project in the world, namely, the South-to-North Water Transfer Project (SNWTP) in China, as an example to analyze the variation of Miyun Reservoir’s inner protection zone functions when water is transferred. Specifically, a riparian model (RIPAM) coupled with remote sensing data were used to calculate the nitrogen (N) and phosphorus (P) losses due to plant uptake, and these results were validated by in situ survey data. Then, correlations between water levels and N and P removal were analyzed. The results show that water table disturbances resulting from elevated water levels strongly influence the growth of plants and have obvious negative impacts on N and P removal in the inner protection zone. With the implementation of the middle route of the SNWTP, the water level of Miyun will rise to 150 m in 2020, and subsequently, the total net primary productivity (NPP) could decline by more than 40.90% from the level in 2015, while the N and P uptake could decline by more than 53.03% and 43.49%, respectively, from the levels in 2015, according to the modeling results. This will lead to declines in the inner protection zone’s defense effectiveness for N and P interception and increases in risks to the security of water resources. The results of this study provide useful knowledge for managing the defense function of the terminal reservoir’s inner protection zone and for ensuring that water quality is maintained during the diversion process. Full article
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Open AccessArticle
Stochastic Linear Programming for Reservoir Operation with Constraints on Reliability and Vulnerability
Water 2018, 10(2), 175; https://doi.org/10.3390/w10020175
Received: 16 December 2017 / Revised: 6 February 2018 / Accepted: 6 February 2018 / Published: 9 February 2018
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Abstract
Reliability and vulnerability (RV) are two very important performance measures but, due to their stage-inseparable nature, they cannot be explicitly incorporated in stochastic dynamic programming (SDP), which is extensively used in reservoir operation. With inflows described as a Markov chain, a stochastic linear [...] Read more.
Reliability and vulnerability (RV) are two very important performance measures but, due to their stage-inseparable nature, they cannot be explicitly incorporated in stochastic dynamic programming (SDP), which is extensively used in reservoir operation. With inflows described as a Markov chain, a stochastic linear programming (SLP) model is formulated in this paper to explicitly incorporate the RV constraints in the reservoir operation, aimed at maximizing the expected power generation by determining the optimal scheduling decisions and their probabilities. Simulation results of the SLP and SDP models indicate the equivalence of the proposed SLP and SDP models without considering the RV constraints, as well as the strength of the SLP in explicitly incorporating the RV constraints. A simulated scheduling solution also reveals a reduction of power generation fluctuation, with the reservoir capacity emptied in advance to meet given reliability and vulnerability. Full article
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Open AccessArticle
Multiple Climate Change Scenarios and Runoff Response in Biliu River
Water 2018, 10(2), 126; https://doi.org/10.3390/w10020126
Received: 19 October 2017 / Revised: 25 January 2018 / Accepted: 26 January 2018 / Published: 30 January 2018
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Abstract
The impacts of temperature and precipitation changes on regional evaporation and runoff characteristics have been investigated for the Biliu River basin, which is located in Liaoning Province, northeast China. Multiple climate change scenarios from phase 3 and phase 5 of the Coupled Model [...] Read more.
The impacts of temperature and precipitation changes on regional evaporation and runoff characteristics have been investigated for the Biliu River basin, which is located in Liaoning Province, northeast China. Multiple climate change scenarios from phase 3 and phase 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5) (21 scenarios in total) were utilized. A calibrated hydrologic model—SWAT model—was used to simulate future discharges based on downscaled climate data through a validated morphing method. Results show that both annual temperature and precipitation increase under most of the CMIP3 and CMIP5 scenarios, and increase more in the far future (2041–2065) than in the near future (2016–2040). These changes in precipitation and temperature lead to an increase in evaporation under 19 scenarios and a decrease in runoff under two-thirds of the selected scenarios. Compared to CMIP3, CMIP5 scenarios show higher temperature and wider ranges of changes in precipitation and runoff. The results provide important information on the impacts of global climate change on water resources availability in the Biliu River basin, which is beneficial for the planning and management of water resources in this region. Full article
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Open AccessArticle
Estimating Carbon Dioxide (CO2) Emissions from Reservoirs Using Artificial Neural Networks
Water 2018, 10(1), 26; https://doi.org/10.3390/w10010026
Received: 3 November 2017 / Revised: 15 December 2017 / Accepted: 28 December 2017 / Published: 1 January 2018
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Abstract
Freshwater reservoirs are considered as the source of atmospheric greenhouse gas (GHG), but more than 96% of global reservoirs have never been monitored. Compared to the difficulty and high cost of field measurements, statistical models are a better choice to simulate the carbon [...] Read more.
Freshwater reservoirs are considered as the source of atmospheric greenhouse gas (GHG), but more than 96% of global reservoirs have never been monitored. Compared to the difficulty and high cost of field measurements, statistical models are a better choice to simulate the carbon emissions from reservoirs. In this study, two types of Artificial Neural Networks (ANNs), Back Propagation Neural Network (BPNN) and Generalized Regression Neural Network (GRNN), were used to predict carbon dioxide (CO2) flux emissions from reservoirs based on the published data. Input variables, which were latitude, age, the potential net primary productivity, and mean depth, were selected by Spearman correlation analysis, and then the rationality of these inputs was proved by sensitivity analysis. Besides this, a Multiple Non-Linear Regression (MNLR) and a Multiple Linear Regression (MLR) were used for comparison with ANNs. The performance of models was assessed by statistical metrics both in training and testing phases. The results indicated that ANNs gave more accurate results than regression models and GRNN provided the best performance. With the help of this GRNN, the total CO2 emitted by global reservoirs was estimated and possible CO2 flux emissions from a planned reservoir was assessed, which illustrated the potential application of GRNN. Full article
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Open AccessArticle
Quantifying the Effects of Near-Bed Concentration on the Sediment Flux after the Operation of the Three Gorges Dam, Yangtze River
Water 2017, 9(12), 986; https://doi.org/10.3390/w9120986
Received: 12 November 2017 / Revised: 11 December 2017 / Accepted: 15 December 2017 / Published: 18 December 2017
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Abstract
The regime of sediment transport in the Jingjiang Reach has significantly changed from quasi-equilibrium to sub-saturation since the impoundment of the Three Gorges Dam (TGD), and vertical profiles of suspended sediment concentration (SSC) have changed accordingly. Vertical profiles of SSC data measured at [...] Read more.
The regime of sediment transport in the Jingjiang Reach has significantly changed from quasi-equilibrium to sub-saturation since the impoundment of the Three Gorges Dam (TGD), and vertical profiles of suspended sediment concentration (SSC) have changed accordingly. Vertical profiles of SSC data measured at three hydrological stations in the Jingjiang Reach (Zhicheng, Shaishi, and Jianli), before and after the impoundment of TGD, were collected and analyzed. Analytic results indicate a remarkably large concentration in the near-bed zone (within 10% of water depth from the river-bed) in a sub-saturated channel. The maximum measured concentration was up to 15 times the vertical average concentration, while the ratio in quasi-equilibrium channel was less than four times that. Concentrations normalized with reference concentration at the same height, and may decrease with increasing values of suspension index (settling velocity over shear velocity). In addition, concentration near the water surface may be larger than concentration in the near-bed region when the suspension index is smaller than 0.01. Sediment flux transported in the near-bed zone may be up to 35% of the total sediment flux in unsaturated flows. The relationship between deviations of estimating sediment flux when ignoring the near-bed concentration and discharge in flood season and non-flood season are different in unsaturated and quasi-equilibrium channels. Analysis indicates that, in the quasi-equilibrium channel, more attention should be paid to near-bed concentration during non-flood season, the same as measurements during flood season with larger discharge. Full article
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Open AccessArticle
Estimating Sediment Flushing Efficiency of a Shaft Spillway Pipe and Bed Evolution in a Reservoir
Water 2017, 9(12), 924; https://doi.org/10.3390/w9120924
Received: 9 October 2017 / Revised: 22 November 2017 / Accepted: 22 November 2017 / Published: 28 November 2017
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Abstract
Control of reservoir sedimentation in order to ensure their sustainable use has drawn attention among water engineers and water resource managers. Several methods have been proposed, but most of the developed methodologies are incapable of modelling bed evolutions, while at the same time, [...] Read more.
Control of reservoir sedimentation in order to ensure their sustainable use has drawn attention among water engineers and water resource managers. Several methods have been proposed, but most of the developed methodologies are incapable of modelling bed evolutions, while at the same time, compute sediment flushing efficiency. In this study a two-dimensional bed evolution model is proposed to estimate sediment distribution, bed evolution and sediment flushing efficiency of reservoirs. A-Gong-Dian reservoir, in southern Taiwan, is used as an illustrative example. Typhoon events were used to verify the proposed model. Simulations were conducted for one and two-day storm events under return periods, 2, 5, 10, 25, 50, 100, and 200-year. The results indicated that the average sediment flushing efficiency of the shaft spillway under one and two-day storms were close, 58.50% and 59.39%, respectively. These results were similar to observed laboratory tests experiments, where an efficiency of 65.34% was obtained. This study suggests that the applied model could be adopted to ensure the sustainable use of reservoirs, and also to find an optimal area for the location of a shaft spillway pipe. Therefore, the proposed model could serve as a reference to the reservoir management personnel. Full article
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Open AccessArticle
Three-Dimensional Numerical Study of Free-Flow Sediment Flushing to Increase the Flushing Efficiency: A Case-Study Reservoir in Japan
Water 2017, 9(11), 900; https://doi.org/10.3390/w9110900
Received: 12 October 2017 / Revised: 10 November 2017 / Accepted: 14 November 2017 / Published: 19 November 2017
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Abstract
The catchment of the Dashidaira reservoir located on the Kurobe River has high sediment yield. Because of the sufficient available amount of water in the catchment during flood events, the free-flow sediment flushing operation with full water-level drawdown is employed every year to [...] Read more.
The catchment of the Dashidaira reservoir located on the Kurobe River has high sediment yield. Because of the sufficient available amount of water in the catchment during flood events, the free-flow sediment flushing operation with full water-level drawdown is employed every year to preserve the effective storage capacity of the Dashidaira reservoir. This paper focuses first on the numerical simulation of a previously conducted free-flow flushing operation in the Dashidaira reservoir using the available in situ obtained data. Afterwards, to improve the flushing efficiency, the effects of water and discharge manipulation and the construction of an auxiliary channel on the total volume of the flushed sediment were studied. A fully 3D numerical model using the finite volume approach in combination with a wetting/drying algorithm was utilized to reproduce the flow velocity field and simulate the movable bed variations. The outcomes revealed that increasing the average free-flow discharge during the free-flow stage by approximately 56%, in the form of multiple discharge pulses, can enhance the flushing efficiency by up to 13%, and the construction of an auxiliary channel in the wide midstream of the reservoir can locally increase the sediment erosion from this area. Full article
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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; https://doi.org/10.3390/w9100783
Received: 7 September 2017 / Revised: 9 October 2017 / Accepted: 10 October 2017 / Published: 12 October 2017
Cited by 10 | 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
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