Water Transfer Triggering Mechanism for Multi-Reservoir Operation in Inter-Basin Water Transfer-Supply Project

This paper proposes a new water transfer triggering mechanism for multi-reservoir system to divert water from abundant to scarce regions with a constant diversion flow in an inter-basin water transfer-supply project. Taking into account of the uncertain nature of inflow, the storage of reservoir is taken as a signal for decision-making to indicate water abundance or water scarcity. In this study, a set of rule curves based on storage of donor reservoir and storage of recipient reservoir are used together to determine when to start water transfer. To initiate water diversion to each recipient reservoir effectively, several water transfer rule curves of the donor reservoir are set for each recipient reservoir respectively in the multi-reservoir system with one donor reservoir and several recipient reservoirs, which is the main difference in comparison with other water transfer triggering mechanisms. In addition, a systematic framework is developed to integrate the water transfer rule curves with hedging rule curves to simultaneously solve the water transfer and water supply problems, since they interact with each other during the operation process. In order to verify the utility of the new water transfer triggering mechanism, an inter-basin water transfer-supply project in China is used as a case study and an improved particle swarm optimization algorithm (IPSO) with a simulation model is adopted for optimizing the decision variables. The results show that the proposed water transfer triggering mechanism can improve the operation performances of the inter-basin system.     

Simulation-optimization model of reservoir operation based on target storage curves

This paper proposes a new storage allocation rule based on target storage curves. Joint operating rules are also proposed to solve the operation problems of a multi-reservoir system with joint demands and water transfer-supply projects. The joint operating rules include a water diversion rule to determine the amount of diverted water in a period, a hedging rule based on an aggregated reservoir to determine the total release from the system, and a storage allocation rule to specify the release from each reservoir. A simulation-optimization model was established to optimize the key points of the water diversion curves, the hedging rule curves, and the target storage curves using the improved particle swarm optimization （IPSO） algorithm. The multi-reservoir water supply system located in Liaoning Province, China, including a water transfer-supply project, was employed as a case study to verify the effectiveness of the proposed join operating rules and target storage curves. The results indicate that the proposed operating rules are suitable for the complex system. The storage allocation rule based on target storage curves shows an improved performance with regard to system storage distribution.     

Real-Time Operation of Reservoir System by Genetic Programming

Reservoir operation policy depends on specific values of deterministic variables and predictable actions as well as stochastic variables, in which small differences affect water release and reservoir operation efficiency. Operational rule curves of reservoir are policies which relate water release to the deterministic and stochastic variables such as storage volume and inflow. To operate a reservoir system in real time, a prediction model may be coupled with rule curves to estimate inflow as a stochastic variable. Inappropriate selection of this prediction model increases calculations and impacts the reservoir operation efficiency. Thus, extraction of an operational policy simultaneously with inflow prediction helps the operator to make an appropriate decision to calculate how much water to release from the reservoir without employing a prediction model. This paper addresses the use of genetic programming (GP) to develop a reservoir operation policy simultaneously with inflow prediction. To determine a water release policy, two operational rule curves are considered in each period by using (1) inflow and storage volume at the beginning of each period and (2) inflow of the 1^st, 2^nd, 12^th previous periods and storage volume at the beginning of each period. The obtained objective functions of those rules have only 4.86 and 0.44?% difference in the training and testing data sets. These results indicate that the proposed rule based on deterministic variables is effective in determining optimal rule curves simultaneously with inflow prediction for reservoirs.     

跨流域引水后受水水库引水与供水联合调度研究

针对跨流域引水工程中受水水库引水与供水联合调度问题，建立了供水量最大与引水效率最高的多目标联合调度模型，并将其分解成两个单目标调度模型，应用长系列模拟优化的方法， 求解受水水库引水与供水联合调度图及其调度规则。以大伙房水库输水应急入连工程规划为基础，采用本文建立的模型方法对其受水水库碧流河水库进行实例研究，先后求解引水后水库最大可供水量以及如何高效引水的问题。结果表明，进行联合优化调度后，可提高跨流域引水的有效性，从而增加受水水库的综合效益。     

基于引水限制调度线的并联水库系统供水优化算法及应用

以实现梯级水库群或者水源连通工程水量补偿式调节为目标,针对并联水库的联合供水特征,采用引水限制调度线控制引水水库可引水量,引入粒子群算法构建了并联水库优化调度模型。通过优化引水调度线提出可以改进并联水库系统的调度规则和调度方法,将优化和常规调度有机结合,并根据并联水库系统实际运行条件设置模型的目标函数、约束条件和参数设置方法。以X市S水库和L水库组成的并联水库系统为实例,采用该模型进行优化模拟。结果表明:并联水库系统经优化年均弃水量比两库单独供水的弃水量减少5 496万m~3,末库容比两库单独供水时提高203万m~3。在95%供水保证率时,并联水库系统供水系统的年供水能力比双库单独供水能力之和提高了5 556万m~3。优化形成的引水限制调度线分布形态合理,并联供水系统经过优化大幅度提高了水库系统的供水能力,证明了基于引水限制调度线的并联水库系统供水优化算法的可行性,该方法对并联水库联合调度具有重要参考价值。     

基于模拟-优化模式的供水水库群联合调度规则研究

提出了基于模拟-优化模式的混联供水水库群联合优化调度规则求解框架。首先，通过构建虚拟聚合水库，编制联合调度图，以做出水库群对各用水户的供水方案；其次，通过优化成员水库供水任务分配因子，并结合供水水库群常规调度规则，实现共同供水任务在水库间的优化分配。采用NSPSO算法对观音阁-葠窝-汤河水库群联合供水调度模型决策变量（联合调度图调度线位置和成员水库供水任务分配因子）进行多目标优化，分析联合供水调度过程中目标之间的竞争关系，检验联合调度规则的合理性与有效性以及NSPSO算法的优化效率。     

跨流域供水水库群联合调度规则研究

针对跨流域供水水库群联合调度存在的主从递阶结构,提出了调水规则和供水规则相结合的跨流域供水水库群联合调度规则。其中,调水规则由一组基于各水库蓄水量的调水控制线表示,根据其间的相对位置关系,决定是否调水,调水量如何分配等;供水规则由各库供水调度图表示,对应于不同用水户的限制供水线将水库的兴利库容分为若干调度区。建立了适合于主从递阶结构的水库群联合调度二层规划模型,采用并行种群混合进化的粒子群算法对模型进行求解。中国北方某大型跨流域调水工程的实例研究证明了模型的合理性和有效性。     

Integrated Reservoir Management System for Adaptation to Climate Change: The Nakdong River Basin in Korea

This study begins with the premise that current reservoir management systems do not take into account the potential effects of climate change on optimal performance. This study suggests an approach in which multi-purpose reservoirs can adapt to climate change using optimal rule curves developed by an integrated water resources management system. The system has three modules: the Weather Generator model, the Hydrological Model, and the Differential Evolution Optimization Model. Two general circulation models (GCMs) are selected as examples of both dry and wet conditions to generate future climate scenarios. This study is using the Nakdong River basin in Korea as a case study, where water supply is provided from the reservoir system. Three different climate change conditions (historic, wet and dry) are investigated through the compilation of six 60 years long scenarios. The optimal rule curves for three multi-purpose reservoirs in the basin are developed for each scenario. The results indicate that although the rule curve for large-size reservoir is less sensitive to climate change, medium or small-size reservoirs are very sensitive to those changes. We further conclude that the large reservoir should be used to release more water, while small or medium-size reservoirs should store inflow to mitigate severe drought damages in the basin.     

Derivation of Aggregation-Based Joint Operating Rule Curves for Cascade Hydropower Reservoirs

Operating rule curves have been widely applied to reservoir operation, due to their ease of implementation. However, these curves are generally used for single reservoirs and have rarely been applied to cascade reservoirs. This study was conducted to derive joint operating rule curves for cascade hydropower reservoirs. Steps in the proposed methodology include: (1) determining the optimal release schedule using dynamic programming to solve a deterministic long-term operation model, (2) identifying the forms of operating rule curves suitable for cascade hydropower reservoirs based on the optimal release schedule, (3) constructing a simulation-based optimization model and then using the non-dominated sorting genetic algorithm-II (NSGA-II) to identify the key points of the operating rule curves, (4) testing and verifying the efficiency of the generated joint operating rule curves using synthetic inflow series. China’s Qing River cascade hydropower reservoirs (the Shuibuya, Geheyan and Gaobazhou reservoirs) were selected for a case study. When compared with the conventional operating rule curves, the annual power generation can be increased by 2.62% (from 7.27 to 7.46 billion kWh) using the observed inflow from 1951 to 2005, as well as by about 1.77% and 2.52% using the synthetic inflows generated from two alternative hydrologic simulation methods. Linear operating rules were also implemented to simulate coordinated operation of the Qing River cascade hydropower reservoirs. The joint operating rule curves were more efficient and reliable than conventional operating rule curves and linear operating rules, indicating that the proposed method can greatly improve hydropower generation and work stability.     

Optimization of Multi-Reservoir Operating Rules for a Water Supply System

To obtain the optimal releases of the multi-reservoir system, two sets of joint operating rules (JOR-I and JOR-II) are presented based on the aggregation-disaggregation approach and multi-reservoir approach respectively. In JOR-I, all reservoirs are aggregated to an equivalent reservoir, the operating rules of which, the release rule of the system is optimized following operating rule curves coupled with hedging rules. Then the system release is disaggregated into each reservoir according to water supply priorities and the dynamic demand partition approach. In JOR-II, a two-stage demand partition approach is applied to allocate the different demand priorities to determine the release from each reservoir. To assess the reliability and effectiveness of the joint operating rules, the proposed rules are applied to a multi-reservoir system in Liaoning province of China. Results demonstrate that JOR-I is suitable for high-dimensional multi-reservoir operation problems with large-scale inflow data, while JOR-II is suitable for low-dimensional multi-reservoir operation problems with small-scale inflow data, and JOR-II performs better than JOR-I but requires more computation time. The research provides guidelines for the management of multi-reservoir system.     

A Novel Optimization Method for Multi-Reservoir Operation Policy Derivation in Complex Inter-Basin Water Transfer System

Joint operation of multiple reservoir system in inter-basin water transfer-supply project is a complex problem because of the complicated structure and cooperated operation policy. The combination of high-dimensional, multi-peak and multiple constraints makes it incredibly difficult to obtain the optimal rule curves for multi-reservoir operation. In view of this, we constructed a joint optimization operation model, considering both water supply and transfer, and proposed the concept of “shape constraints”. To obtain the solution of this high-dimensional optimization model, a novel progressive optimum seeking method, namely Progressive Reservoir Algorithm-Particle Swarm Optimization (PRA-PSO), is presented based on the nature of progressive optimization algorithm (POA) and standard particle swarm optimization (PSO). The water transfer project in northeast China, consisting of three routes eight reservoirs, is selected as a case study. The results show that (1) PRA-PSO is yielding much more promising results when compared with other optimization techniques; (2) shape constraints would narrow the scope of feasible solution area but increase the convergence of algorithm; (3) because of the strong interaction between water transfer and water supply action, the progressive setting of PRA-PSO should be in accordance with the order of reservoir water transfer. The case study indicates the novel optimization method could effectively increase the chance of jumping out of local optimal points, thereby searching for better solutions.     

Development and application of a simulation model for reservoir management

The success of irrigation system operation and planning depends on accurate quantification of supply and demand, and an equitable distribution of available water. The ultimate aim of this study was to determine how to meet the irrigation water demands if possible or to minimize the gap between the water supply and the demand. Most of the irrigation literature focuses only on the demand and the distribution aspects of this issue Irrigation projects that receive water from reservoirs, however, can be challenging to manage because the annual fluctuations in available water release from a reservoir can have a considerable impact on the irrigation management strategy. In real‐world situations, the reservoir operating rules guide reservoir operators in making actual water release decisions. This study develops a water balance simulation model for reservoir management, as well as testing it for Kangsabati Reservoir, West Bengal, India. Two rule curves for deciding irrigation water available from the reservoir were generated by taking the average and minimum stage values on a daily basis for a 16‐year period (1988–2003). Maintaining a minimum stage of 120.4 m throughout the year served as another rule to decide the release water available for irrigation. The minimum allowable stage of reservoir corresponding to a particular date of the year can be determined from those reservoir specific rule curves generated for irrigation purposes. The maximum permissible water release/outflow for irrigation from the test reservoir was taken as the volume of water available above the minimum allowable stage corresponding to the selected rule curve. The saturated hydraulic conductivity value (K_S) was calibrated to be 4.31 mm day^?1 for Kangsabati Reservoir.     

Reservoir Optimization-Simulation with a Sediment Evacuation Model to Minimize Irrigation Deficits

Importance of existing reservoirs for supplying fresh water has increased significantly due to population increase and enhanced living standards, while the reduced development of new reservoirs in recent decades has made it even more pertinent that the current battery of reservoirs be operated in a sustainable and efficient manner. In order to move a step towards the goal of sustainability, sediment evacuation must be considered when optimizing a reservoir??s operations. The Reservoir Optimization-Simulation with Sediment Evacuation (ROSSE) model is a recently developed tool which internalizes sediment evacuation routines and the simulation module in a newly developed GA-based optimization module. This article applies the ROSSE model with the aim of minimizing irrigation shortages in the Tarbela Reservoir, Pakistan. The article also calculates the suitable values of various GA parameters required to run the model through a sensitivity analysis. Simulation results of three sets of rule curves??one existing and two optimized sets??are compared with each other for parameters like irrigation shortage, power generation, sediment evacuation and flood dis-benefits (damages). It is found that the optimized rule curves of scenario 1 reduce the irrigation shortages by 39?% while the optimized rule curves of scenario 2 can reduce the irrigation shortages by 24?% of that of the shortages by existing rule curves. The optimized rule curves of scenario 2 also ensure the current level of hydropower generation and sediment evacuation for the Tarbela reservoir. The study recommends a change in the reservoir??s existing rule curves in order to reduce irrigation shortages. The incorporation of the sediment evacuation routine and availability of economic and hydro based objective functions in the optimization model will help achieving the goal of sustainability.     

Optimization and risk analyses for rule curves of reservoir operation: application to Tien-Hua-Hu Reservoir in Taiwan.

Tien-Hua-Hu Reservoir is currently under planning by the Water Resources Agency, Taiwan to meet the increasing water demands of central Taiwan arising from rapid growth of domestic water supply, and high-tech industrial parks. This study develops a simulation model for the ten-day period reservoir operation to calculate the ten-day water shortage index under varying rule curves. A genetic algorithm is coupled to the simulation model to find the optimal rule curves using the minimum ten-day water shortage index as an objective function. This study generates many sets of synthetic streamflows for risk, reliability, resiliency, and vulnerability analyses of reservoir operation. ARMA and disaggregation models are developed and applied to the synthetic streamflow generation. The optimal rule curves obtained from this study perform better in the ten-day shortage index when compared to the originally designed rule curves from a previous study. The optimal rule curves are also superior to the originally designed rule curves in terms of vulnerability. However, in terms of reliability and resiliency, the optimal rule curves are inferior to the those originally designed. Results from this study have provided in general a set of improved rule curves for operation of the Tien-Hua-Hu Reservoir. Furthermore, results from reliability, resiliency and vulnerability analyses offer much useful information for decision making in reservoir operation.     

分期径流丰枯遭遇对大伙房水库引水条件的影响

大伙房水库是保障辽宁中南部城市社会经济发展的重要水利工程,而径流条件是影响大伙房水库功能发挥的关键因素。依据大伙房水库及引调水水源区31a的长系列(1980～2010年)径流资料,采用数理统计法及Copula函数分析大伙房水库及引调水水源区径流特点及其分期丰枯补偿特性,基于此,对大伙房水库跨流域引水条件进行系统总结。结果表明:引调水水源区与大伙房水库在全年、春季、汛期、枯水期的径流丰枯同步遭遇概率均在70%以上;引调水水源区在各分期内有62.5%的概率可为大伙房水库提供径流补偿。在今后的研究中,应结合大伙房水库自身多年调节的性能,进一步研究不同径流补偿条件下的引水策略,制定丰、平、枯水年径流补偿条件下的引水调度线。研究结果可为水库经济引水及综合效益发挥提供参考。     

基于Mike Basin的复杂水库群联合调度模型研究

重庆涪陵区龙潭水利工程为由并联、串联水库组成的复杂水库群,水资源配置难度较大,有必要借助数值模拟软件来完成。在Mike Basin水资源配置模型的基础上进行编程计算,提出了用Mike Basin模型计算多功能复杂水库群联合调度的方法,并计算了4种工况下工程运行对下游发电的影响。通过验证发现,该模型可以很好地模拟龙潭水利工程水库群调度现状。对Mike Basin水资源配置模型存在的不足进行了分析,并提出了可行的解决方法,相关结论可为今后运用Mike Basin解决水库群联合调度问题提供参考。     

The application of the aggregative approach in simulation modeling of water resources systems

This is a discussion about constructing simulation models for complex water resources systems (WRS). They are based on the piecewise linear aggregates theory developed in the U.S.S.R. The method allows us to lay down general principles for the construction of such simulation models and automate water resources calculations. Water resources systems simulation models incorporate balance equations, describe water resources inputs into and outputs from sites and reservoirs, and algorithms for both reservoir control and water distribution at sites. Water reservoir control is based on rule curves. The aggregative approach is especially efficient in constructing such algorithms for coordinated control of reservoirs.     

Identifying Explicit Formulation of Operating Rules for Multi-Reservoir Systems Using Genetic Programming

Operating rules have been widely used to handle the inflows uncertainty for reservoir long-term operations. Such rules are often expressed in implicit formulations not easily used by other operators and/or reservoirs directly. This study presented genetic programming (GP) to derive the explicit nonlinear formulation of operating rules for multi-reservoir systems. Steps in the proposed method include: (1) determining the optimal operation trajectory of the multi-reservoir system using the dynamic programming to solve a deterministic long-term operation model, (2) selecting the input variables of operating rules using GP based on the optimal operation trajectory, (3) identifying the formulation of operating rules using GP again to fit the optimal operation trajectory, (4) refining the key parameters of operating rules using the parameterization-simulation-optimization method. The method was applied to multi-reservoir system in China that includes the Three Gorges cascade hydropower reservoirs (Three Gorges and Gezhouba reservoirs) and the Qing River cascade hydropower reservoirs (Shuibuya, Geheyan and Gaobazhou reservoirs). The inflow and storage energy terms were selected as input variables for total output of the aggregated reservoir and for decomposition. It was shown that power energy term could more effectively reflect the operating rules than water quantity for the hydropower systems; the derived operating rules were easier to implement for practical use and more efficient and reliable than the conventional operating rule curves and artificial neural network (ANN) rules, increasing both average annual hydropower generation and generation assurance rate, indicating that the proposed GP formulation had potential for improving the operating rules of multi-reservoir system.     

深水条件下自平衡组合式钢围堰设计与现场试验研究

大型输水渠道衬砌在冻融循环等作用下易产生剥蚀破坏等缺陷,同时渠底反滤排水系统在运行过程中可能会失效,需要进行检修和维修。大型输水工程一般不具有停水或者降低水位运行条件,因此在不停水条件下渠道衬砌面板缺陷与破坏修复技术是大型调水输水工程检修、维护的重点和难点问题之一。以南水北调中线干渠衬砌修复现场试验为依托,进行了一种水下3.0～3.5m钢围堰的结构设计,深入研究了挡水面板、支撑传力系统并进行了有限元受力分析,研究了不同部位结构新型止水型式,提出了便于安装且止水效果好的自平衡组合式围堰成套技术,以及钢围堰水面装配、入水就位及拆卸转场施工技术,并结合现场试验成果进行不断优化,可以为大型输水工程衬砌水下修复干地作业提供有益参考。     

An Improved “Dynamic Control Operation Module” for Cascade Reservoirs

Reservoirs are one of the most efficient projects for water resources management, and also play an important role in flood control and conservation. Dynamic control of the reservoir flood limited water level (FLWL) is considered as an effective factor to ensure safety of the flood control during the flood season. The maximum allowed water level of cascade reservoirs is also a fundamental key element for implementing reservoir water level dynamic control operation. In this paper, we discussed and improved “Dynamic Control Operation Module for Cascade Reservoirs” (DCOMR). Therefore, a set of new formulas and new methodologies were proposed (NDCOMR) which considers intermediate variables forecast information, the release of the upstream reservoir and interval flow forecast information in effective lead times, which is applied to the dynamic operation of the maximum allowed water level of cascade reservoirs. The Bikou and Miaojiaba cascade reservoirs were selected as a case study. Based on numerical experiment results, the maximum allowed water level of cascade reservoirs at current time determined by NDCOMR was much safer than that determined by DCOMR. The NDCOMR is more rational and safer than DCOMR for flood control, without the need of reducing flood control standard.