Coupled Operating Rules for Optimal Operation of Multi-Reservoir Systems

Due to the complexity of multi-reservoir system operation problems, researchers usually prefer to assume lumped demands located downstream of such systems. Consequently, distributed local demands through the system are neglected or supplied completely (e.g. using Standard operating policy, SOP), in order to simplify the problem. In this study, Coupled Operating Rules (COR) as a simple and suitable operating policy is applied for optimal operation of multi-reservoir systems with local demands. The applied policy includes two types of linear rules, which are defined to determine total releases and local water allocations in decision points. This policy is adopted within a simulation-optimization approach to optimally operate a three-reservoir system in the Karkheh river basin. Obtained results indicate that the proposed strategy reduces the intensity of demand deficits and distributes the occurred shortages throughout the system properly. Moreover, the system losses are managed appropriately and big unbalanced local shortages are prevented. Although COR strategy decreases the reliability of local demands compared to SOP, it is a reasonable operating policy for systems with distributed local demand sites. Moreover, in this study an effective Improved Melody Search (IMeS) algorithm is proposed to achieve the optimum values of operating rules’ parameters. The efficiency of the optimization method is compared to the results achieved by other selected well-known heuristic search methods. Based on the experimental results, it is revealed that the proposed algorithm is more effective in finding precise solutions over a long-term period, comparing with the other conventional algorithms.     

Deriving Optimal Operating Rules of a Multi-Reservoir System Considering Incremental Multi-Agent Benefit Allocation

Joint multi-reservoir operation is one of the most efficient measures to meet the demand for increasing economic benefits. Operating rules have been widely used in long-term reservoir operations. However, reservoirs belong to multiple agents in most cases, which imposes difficulties on benefit allocation. This motivated us to derive optimal operating rules for a multi-reservoir system, considering incremental benefit allocation among multiple agents. Fairness of incremental benefits for multiple agents is proposed as one of the objective functions, and then optimal joint operating rules with fairness are derived. The optimal joint operating rules with fairness are compared with conventional, optimal individual, and joint operating rules. The Three Gorges (Three Gorges and Gezhouba) and Qing River (Shuibuya, Geheyan and Gaobazhou) cascade reservoirs are selected for case study. The optimal joint operating rules with fairness not only encourage agents to participate in joint operation, but also increase average annual hydropower generation and the assurance rate of hydropower generation relative to those of the conventional operating rules. Furthermore, the proposed optimal operating rules with fairness are easier to implement in practice than the optimal joint rules. This indicates that the proposed method has potential for improving operating rules of a multi-reservoir system.     

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.     

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 and Optimization of Multi-Reservoir Operation in Inter-Basin Water Transfer System

Inter-basin water transfer projects are usually considered as one of the most effective facilities to balance the non-uniform temporal and spatial distribution of water resources and water demands by diverting water from surplus to deficient area. However, the operation of these projects are always daunting, especially for projects with multi-donor reservoirs but only one recipient reservoir. In this study, a set of water transfer rule curves are firstly proposed to determine when, where and how much water should be diverted from each donor reservoir. In addition, a simulation-optimization model with the objective to minimize both water shortage risk and vulnerability is established to derive the optimal operation rule curves. Following that, the new transfer rules are applied to provide guidelines for the operation of a water transfer-supply project with two donor reservoirs in central China. The effects of water diversion on each reservoir are evaluated under different scenarios including no diversion, diversion from the donor reservoir with relatively sufficient water, diversion from the donor reservoir with relatively limited water, and diversion from both donor reservoirs. The results show the advantages of improving the performance of whole water diversion system and demonstrate the feasibility of the proposed approach.     

水库群联合供水方案模拟优化研究

对于由两个或两个以上水库构成的供水系统,将水库群等效为一个聚合水库,建立联合调度供水模式。通过制定合理的供水调度原则,采用优化水库调度图,根据各库实时可供水量实现供水任务合理分配,模拟水库群联合调度供水过程,得到最优供水方案。将该供水方案应用于某市水库群供水调度中,结果表明:各用水户的供水保证率均高于设计保证率,水库群基本满足该地区的用水需求,验证了所提出的水库群联合调度供水方案的可行性与优越性。     

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.     

Developing Water Cycle Algorithm for Optimal Operation in Multi-reservoirs Hydrologic System

Water Resources Management - Optimal operation of multi-objective reservoirs is one of the complex and, sometimes nonlinear, issues in multi-objective hydrologic system optimization. Meta-heuristic...     

A Comparative Study of Flexibility in Water Allocation in the Context of Hydrologic Variability

River flow that is characterized by variability requires commensurate flexibility in allocating water so that water users are able to plan their activities and respond accordingly. An indicator-based assessment method is proposed in this study to evaluate the flexibility of water allocation, based on a concept that a flexible water allocation regime provides greater opportunity for users to freely decide individual water use and leads to more variability and diversity for water consumption among the users. This is demonstrated by using historical water-use data and applying the assessment method in three river basins with different water allocation regimes. These allocation regimes include the seasonal and volumetric water allocation system in the Yellow River of China, duration-based water allocation in Northwestern China, and capacity sharing in southern Queensland in the northern Murray Darling Basin of Australia. Historical water-use variability and diversity are defined and assessed. The result shows that water allocation flexibility varies across the different water entitlement regimes. Duration-based water allocation, a type of allocation that provides the highest degree of water-use autonomy, is ranked as the most flexible regime. Seasonal water allocation, which has the highest level of centralized regulation, shows the lowest flexibility. The proposed indicator based assessment method would be useful for evaluating the flexibility of policy options for water allocation. This could be helpful for improving the capability of water allocation regimes to cope with the changing environment and improving the effectiveness of water allocation systems.     

Optimizing Multiple Linear Rules for Multi-Reservoir Hydropower Systems Using an Optimization Method with an Adaptation Strategy

Water Resources Management - Water resources crisis has a significant impact on hydropower energy production, which highlights the importance of water resources management. Reservoirs are effective...     

面向可持续利用的武汉市水资源优化配置

 基于"时间和空间耦合"的完整意义上的可持续理论,系统分析了面向可持续利用的水资源优化配置的内涵和原则,并结合武汉市水资源现状与发展趋势,构建了优化配置模型,运用逐步宽容约束法求解模型。以2010年为代表年,按95％的保证率对武汉市水资源优化配置的途径和方法进行了探索。配置结果表明：在P=95％的特别干旱年,全市农业用水保证率大于90％,高增?基本方案为93.07％,高增-节水方案为96.56％,仅江夏、黄陂出现农业缺水;全市第三产业较缺水,高增?基本方案下用水保证率为85.39％,高增-节水方案下用水保证率为93.03％;其它部门用水保证率均达到100％。与常规配置下的水资源供需预测值相比,较大程度提高了用水保证率,验证了模型的科学性和实用性。     

小型农田水利工程可持续运行管理评价

根据小型农田水利工程可持续运行管理的要求,结合其管理现状和管理特点提出了评价指标体系,并将二元语义层次分析法引入可持续运行管理的评价中.以某镇小型农田水利工程可持续运行管理评价为例,计算得到的评价结果与该镇运行管理现状相符,并提出可从资金管理和工程管理方面着手来提高其可持续运行管理的水平.     

区域水资源可持续利用配置模型初探

以可持续发展与和谐观为指导,在以往水资源配置的基础上,综合考虑水资源在社会、经济、生态三方面的合理分配。以社会、经济和生态取得综合效益最大为目标,以水量、输水能力和污水与总用水量的比值的零增长为约束条件,建立了水资源优化配置的多目标模型。     

基于可持续发展的区域水资源优化配置研究

运用可持续发展的水资源优化配置理论,以区域经济发展与水环境保护相协调为目标,建立地下水开采漏斗区水资源多目标优化配置模型。采用多目标遗传算法对漏斗区水资源进行合理配置。优化配置结果表明:基本解决了漏斗区供需矛盾,缓解了地下水的开采压力。     

科学分析水资源规律合理制定水资源配置方案

水资源配置是水资源规划的重要环节。水资源配置方案制定工作步骤大体分技术分析和协调裁决两个阶段，基本步骤为：一是通过资源评价阶段的工作得到水资源状况、资源利用和生态环境台账，为水资源配置奠定基础；二是确定最小生态用水以及生产和生活用水量及其潜力；三是提出最大可利用水量的控制指标和排放控制指标；四是提出水资源配置的推荐方案；五是比较分析并协商确立流域的水资源配置方案。水资源配置的技术方案分析要做好五方面工作：供水预测、水资源保护、需水预测、节约用水和配置方案分析。通过以上工作制定出合理的符合实际的最优水资源配置方案。     

Optimal Agricultural Water Allocation for the Sustainable Development of Surface and Groundwater Resources

This paper presents a multiobjective linear program for the optimal allocation of water resources among various crops in a large canal command area of Pakistan. The available surface water in the canal cannot meet the net irrigation requirement (NIR) of various crops, which leads to the overexploitation of groundwater and causes salinity problems. Therefore, an optimal water allocation model was formulated using the simultaneous compromise constraint (SICCON) technique for the sustainable development of surface water and groundwater. Three (03) single objective functions (OFs) and a multiobjective function (MOF) were considered in this study. The MOF combines the single OFs by developing an arrangement among them to both maximize the satisfaction rate for surface water (SR_s) and net economic returns (NER) and minimize the salinity problems. The available surface water (AW) of 1531 Mm³ was allocated among various crops, i.e., wheat, cotton, sugarcane, rice, onion, and sunflower, using the SICCON technique, and the deficit was accounted for with groundwater reserves. The model results showed an average increase of 22% in SR_s and 7.2 million USD in NER_s from surface water allocation compared to the current water allocation practice. Moreover, the salinity levels of the allocated water exceed the threshold limits of onion, sugarcane, and rice crops in the current water allocation system and thereby negatively impact agricultural production. Hence, the model used in this study may support decision-makers in the optimal selection of different crops to be irrigated to maximize the SR_s and NER_s and minimize salinity problems.

     

An Inexact Two-Stage Water Resources Allocation Model for Sustainable Development and Management Under Uncertainty

In this study, an inexact two-stage water resources allocation (ITWR) model is put forward for supporting sustainable development and management of water resources in Sanjiang Plain, China, which is in such a situation, with multi-water source, multi-water supply subarea, multi-water user and multi-planning goal. The costs of net system, water supply and recourse are analyzed. The developed ITWR model, which shows a strong ability in tacking with various uncertain factors in probability distributions and discrete interval numbers, mixes the techniques of interval-parameter programming (IPP) and two-stage stochastic programming (TSP) within a general optimization framework. And it also has formed an effective link in such a conflict between the policy scenarios and the associated various levels of economic penalties, when the pre-allocation targets of water resources are violated. Based on this model, a series of scenarios under different levels of pre-allocation water is done and different degrees of water surplus and shortage are obtained correspondingly. The results indicate that the reasonable distribution plans with maximum system benefit and minimum system-failure risk have been generated. And these results are valuable for saving water resources to realize its sustainable development and mitigating the penalty to gain economic benefits maximum, and thus some desired results are provided for decision makers in tackling with a complex and uncertain water-resource system.     

Sustainable Water Supply and Demand Management in Semi-arid Regions: Optimizing Water Resources Allocation Based on RCPs Scenarios

Climate as one of the key factors in water resources management affects the amount of water in the hydrological cycle, which subsequently impacts the level of water availability. Considering the challenges that the South Alborz Region, Iran is currently facing in supplying water for various consumers; in this study, the climate change adaptation scenarios are investigated for sustainable water supply and demand. This study uses a procedure in which five different adaptation approaches, under RCPs scenarios, were established using the WEAP model to assess the impacts of various adaptation strategies on increasing the balance between water supply and demand over current and 2020s accounts. The findings suggest an imbalance between supply and demand in the current situation with the greatest imbalance in domestic use while the minimum in the industrial sector. The results of assessing adaptive scenarios show that various scenarios have different effects on balancing the water supply and demand by different consumers; on the other hand, the scenarios that directly affect domestic water demand have the greatest effect on minimizing the gap between supply and demand in the region; therefore, the options for decreasing the population demand along with diminishing the losses in the domestic water distribution network are the most effective alternatives for balancing supply and demand under all of the climate scenarios. The findings of this research indicate that adaptive management with the focus on restricting demand helps actively management of water resources in the regions with scarce water resources.

     

Managing Irrigation Water Shortage: a Comparison Between Five Allocation Rules Based on Crop Benefit Functions

In this work the efficiency of five allocation rules of irrigation water is analyzed and compared. We define the most efficient rule as the one that minimizes the economic losses arising from a reduction in water availability. The first allocation rule is an equal quota granted to all irrigators. The second one is based on proportional reductions. By means of the third rule all losses of income per hectare are matched, while the fourth makes that all relative losses to the reference incomes are matched. Lastly the fifth rule seeks to maximize private benefit and economic efficiency. We prove that this one would likely be preferred by farmers growing more than one crop. The fundamentals of these rules are included, showing the analytical deduction of the crop-specific reallocations from any prescribed water reduction rule within an irrigation district, as well as the losses of income ensuing from reduced water deliveries. The methodology used herein to compare the efficiency of all these rules is dependent on the relations between allocations and yields. To estimate them, a simple and practical procedure is presented. The five allocation rules are applied to an irrigation community and compared to each other in terms of economic efficiency. Differences in economic losses arising from one rule or another will be sharper the more heterogeneous communities are. Different losses across rules will also be related to the level of water shortage.     

Simulation with RBF Neural Network Model for Reservoir Operation Rules

Reservoirs usually have multipurpose, such as flood control, water supply, hydropower and recreation. Deriving reservoirs operation rules are very important because it could help guide operators determine the release. For fulfilling such work, the use of neural network has presented to be a cost-effective technique superior to traditional statistical methods. But their training, usually with back-propagation (BP) algorithm or other gradient algorithms, is often with certain drawbacks. In this paper, a newly developed method, simulation with radial basis function neural network (RBFNN) model is adopted. Exemplars are obtained through a simulation model, and RBF neural network is trained to derive reservoirs operation rules by using particle swarm optimization (PSO) algorithm. The Yellow River upstream multi-reservoir system is demonstrated for this study.