A Fuzzy Stochastic Dynamic Nash Game Analysis of Policies for Managing Water Allocation in a Reservoir System

In this paper a fuzzy dynamic Nash game model of interactions between water users in a reservoir system is presented. The model represents a fuzzy stochastic non-cooperative game in which water users are grouped into four players, where each player in game chooses its individual policies to maximize expected utility. The model is used to present empirical results about a real case water allocation from a reservoir, considering player (water user) non-cooperative behavior and also same level of information availability for individual players. According to the results an optimal allocation policy for each water user can be developed in addition to the optimal policy of the reservoir system. Also the proposed model is compared with two alternative dynamic models of reservoir optimization, namely Stochastic Dynamic Programming (SDP) and Fuzzy-State Stochastic Dynamic programming (FSDP). The proposed modeling procedures can be applied as an appropriate tool for reservoir operation, considering the interaction among the water users as well as the water users and reservoir operator.     

The Integrated Management of Water Resources in Marina Baja (Alicante, Spain). A Simultaneous Equation Model

In the Marina Baja region there is a tradition of fierce competition for water resources which necessitates the regulation of institutions in order to satisfy the interests of the different water users. The management of the water resources in this region is based on the water exchange between the different users with no legal modification of the water concessions. This situation requires continuous negotiation in order to maintain the balance between urban, tourism and the agricultural demand. In this article we define, describe and analyse the equilibrium model for water resources of the Marina Baja District using a simultaneous equations model (SEM). We analyse variables that influence the water management model through a simultaneous relationship between the above-mentioned demands in the region of the Marina Baja, using a methodology that directly links urban and irrigation demands and makes them relevant to one another from a socioeconomic point of view.     

基于仿真规则与智能优化的水库多目标调控模型及其应用

为解决多个用户的用水竞争矛盾,改变经济社会用水长期挤占生态环境用水的不合理现状,把水库下游的河流生态系统作为一个独立用水户,进而按照水库用水户的优先级,制定水库分区供水调度仿真规则;为解决水库调度方案的最优性与可操作性的统一问题,构建多用户供水保证率最大化且尽可能均衡的水库优化调度模型目标函数;在此基础上建立了基于仿真规则与智能优化的水库多目标调控模型。以潘家口水库为例,计算了现状供水规模下的水库调度方案,绘制了水库多用户分区供水调度图。结果表明:本文模型有效,提出的水库分区调度方案较之现行调度,可在不降低兴利和防洪效益的前提下,显著提高水库下游河道生态系统的供水保证率。     

EVALUATING TRADEOFFS BETWEEN ENVIRONMENTAL FLOW PROTECTIONS AND AGRICULTURAL WATER SECURITY

River basin managers responsible for water allocation decisions are increasingly required to evaluate tradeoffs between environmental flow protections and human water security. However, the basin‐scale effects of environmental flow regulations on water users are not well understood, in part because analyses are complicated by the spatial and temporal variation in water availability, human demands, and ecosystem needs. Here, we examine alternative regional environmental flow policies and their effects on a distributed network of water users in a small (182 km²) river basin in coastal California. We use a hydrologic model to simulate water diversion operations under three policy scenarios and quantify potential impacts to bypass flows for adult migrating salmon and agricultural water storage. The results indicate that there are inherent tradeoffs between environmental flows and agricultural water security, with the most restrictive environmental policy associated with the greatest impacts to water users. Surprisingly, the moderate environmental flow policy had larger impacts to bypass flows than the unregulated management scenario, suggesting that ecological benefits of the moderate policy are small relative to the adverse effects on agricultural water users. Conflicts between environmental and human water needs were greatest in upper catchments (<2.5 km²), where flow protections caused the greatest reduction in water storage. Although natural supplies were adequate for meeting water needs in most years regardless of policy restrictions, potential for conflict between environmental flow protections and water security was evident in dry years. Therefore, strategies are particularly needed for drought‐year water management to ensure adequate environmental flows while reducing human water allocations in an equitable manner. Copyright © 2013 John Wiley & Sons, Ltd.     

基于成本加成的再生水阶梯定价方法研究

再生水作为城市的第二水源,能有效缓解水资源危机。以再生水管网建设的资金回收为前提条件,运用成本加成的方法,确定用户使用再生水的成本价格与需求量、输水距离之间的函数关系,并根据用户与水厂之间的距离划分不同的用户群;进而针对用户群内用户需求量的差异,采用阶梯定价的方法对再生水的价格制定进行研究,建立了基于再生水用户需水量、输水距离等因素的复合阶梯定价模型。最后,以西安市第二污水处理厂为例,运用模型计算其用户-西郊热电厂的再生水使用价格,验证了此定价模型的准确性与实用性,为再生水价格市场化发展提供了理论依据。     

Urban Water Demand for Service and Industrial Use: The Case of Zaragoza

Increased efforts to improve urban water management are focused on demand side policies, seeking to affect the behavior of users so that a “reasonable” use of water resources is reached. In this framework the accurate characterization of water demand play a major role in obtaining sufficient knowledge about this behavioral response to changes in price. In this paper we focus on the water demand of the services and industries connected to the public water network. To this end, we carry out an empirical estimation of urban water demand for service and industrial use in Zaragoza (Spain). The proposed model is a Koyck flow adjustment demand model, and a price specification, which is constructed as a function of the lagged average price, current marginal price and a price perception parameter. We use a dynamic panel data methodology to estimate the water demand function. As far as we are aware, this approach to service and industrial urban water demand is new in the literature. The analysis suggests that although price has a negative relationship with consumption, such an effect is reduced given that the price elasticity is lower than one in absolute value. Another relevant finding is that service and industrial urban users think that they pay a lower price than the actual price they pay.     

Robust Methods for Identifying Optimal Reservoir Operation Strategies Using Deterministic and Stochastic Formulations

Water allocation in a competing environment is a major social and economic challenge especially in water stressed semi-arid regions. In developing countries the end users are represented by the water sectors in most parts and conflict over water is resolved at the agency level. In this paper, two reservoir operation optimization models for water allocation to different users are presented. The objective functions of both models are based on the Nash Bargaining Theory which can incorporate the utility functions of the water users and the stakeholders as well as their relative authorities on the water allocation process. The first model is called GA–KNN (Genetic Algorithm–K Nearest Neighborhood) optimization model. In this model, in order to expedite the convergence process of GA, a KNN scheme for estimating initial solutions is used. Also KNN is utilized to develop the operating rules in each month based on the derived optimization results. The second model is called the Bayesian Stochastic GA (BSGA) optimization model. This model considers the joint probability distribution of inflow and its forecast to the reservoir. In this way, the intrinsic and forecast uncertainties of inflow to the reservoir are incorporated. In order to test the proposed models, they are applied to the Satarkhan reservoir system in the north-western part of Iran. The models have unique features in incorporating uncertainties, facilitating the convergence process of GA, and handling finer state variable discretization and utilizing reliability based utility functions for water user sectors. They are compared with the alternative models. Comparisons show the significant value of the proposed models in reservoir operation and supplying the demands of different water users.     

基于多目标决策分析的五家渠市水资源优化配置研究

针对五家渠市在快速发展社会经济时所面临的多水源、多用水户、工农业用水矛盾日渐突出等用水问题,采用多目标决策的方法建立以缺水量最小和引水费用最小为目标函数的水资源优化配置模型,对五家渠市未来规划年(2015、2030)的水资源进行规划配置,成果分析表明优化配置的结果合理,具有实用性和协调性等优点。     

Incorporating Water Demand Management into a Cooperative Water Allocation Framework

The impact of a water demand management plan on a water system and its users is investigated within a comprehensive cooperative water allocation framework. In particular, a demand management plan is incorporated into a two-step multi-period fair water allocation model. A modified cooperative game is designed for the sharing of additional net benefits under the scenario having water demand management. The results indicate that cooperation among water users can yield more net benefits, and a water demand management plan is able to lead to a further increase of the aggregated net benefits by means of water transfers from less productive users to more productive ones. By utilizing the modified cooperative game, fair sharing of additional net benefits ensures that every water user can expect to receive more net benefits and thereby water users are motivated by incentives to implement a water demand management plan which in turn improves water use efficiency. The results demonstrate that the demand management plan can be of great assistance in some arid and semi-arid regions.     

A Multi-objective Linear Programming Model with Interval Parameters for Water Resources Allocation in Dalian City

Water resources management has been of concern for many researchers since the contradiction between increased water demand and decreased water supply has become obvious. In the real world, water resources systems usually have complexities among social, economic, natural resources and environmental aspects, which leads to multi-objective problems with significant uncertainties in system parameters, objectives, and their interactions. In this paper, a multi-objective linear programming model with interval parameters has been developed wherein an interactive compromising algorithm has been introduced. Through interactive compromising conflicts among multi-objectives, a feasible solution vector can be obtained. The developed model is then applied to allocation of multi-source water resources with different water qualities to multiple users with different water quality requirements for the Dalian city for 2010, 2015 and 2020 planning years. The model pursues the maximum synthesis benefits of economy, society and the environment. The results indicate that the proportion of reused water to the total water amount is gradually increasing, and the proportion of agricultural water consumption to the total water consumption is gradually decreasing. The allocation of multi-source water resources to multiple users is improved due to incorporation of uncertain factors into the model that provide useful decision support to water management authorities.     

The Application of a Water Rights Trading Model Based on two-Stage Interval-Parameter Stochastic Programming

In recent decades, increasing conflicts have occurred between different water users because of issues related to water resource allocation. To better allocate water resources, this study adopts the latest water rights trading model instead of the traditional water resources allocation model and combines it with a two-stage interval-parameter stochastic programming model (TISP). The combined model was applied to the Sanjiang Plain with multi-area, multi-source, and multi-water users, and the optimized promised water availability for every user in the area was obtained. The analysis shows that a higher promised water availability corresponds to a higher benefit but also promotes additional risks because of water shortages, whereas a lower promised water availability corresponds to a lower benefit, although it is more likely to result in water waste at high inflow levels. The combined model formed an effective link between water use benefits and water deficiency punishments that enabled us to obtain an optimized promised water availability that considers benefits and risks simultaneously. The second result is that the water rights trading model can improve the utilization efficiency of water resources, which are typically transferred from inefficient water use areas to efficient water use areas, resulting in a benefit to all areas. Additionally, in the water rights trading model, self-profit motivation at a micro-level can emerge in adaptation at a macro-level, which stabilizes the water resource system and reduces the possibility of system collapse because of extreme water shortages.     

Water Resources Allocation Using a Cooperative Game with Fuzzy Payoffs and Fuzzy Coalitions

In this paper, two fuzzy cooperative games are utilized for modeling equitable and efficient water allocation among water users in both inter-basin and intra-basin water allocation problems. The proposed all-inclusive water allocation approach consists of three main steps, following Sadegh et al. (Water Resour Manage 24(12):2991?C2310, 2010). In the first step, an initial water allocation is carried out using an optimization model taking into account an equity criterion. In the second step, the water users form crisp coalitions with fuzzy characteristic functions to increase the total net benefit of the system and also their own benefits. In the methodology used in this step, the water users do not need to have exact information about their payoffs and they can evaluate their payoffs as fuzzy numbers. In the second step, based on the Hukuhara difference of fuzzy numbers, optimum water allocation strategies are determined using a game with fuzzy characteristic function. In the third step, we applied another methodology which considers a class of fuzzy games with fuzzy characteristic functions and also fuzzy coalitions for water allocation. The methodology of this step is on the basis of the Hukuhara difference and the Choquet integral. The usefulness of the mentioned methodologies is studied by applying them to three defined real life scenarios in a case study of water allocation in Iran. The results showed that the proposed methodologies are professionally appropriate to real-world uncertain problems of equitable and economic inter-basin and intra-basin water resources allocations.     

不确定性多目标模糊规划在水资源优化配置中的应用

在充分考虑水资源系统中供需水不确定性的基础上,基于多目标规划、模糊规划和区间规划原理,以经济效益、社会效益和环境效益最大为目标,以需水量、可供水量和不同子区用水部门间的用水公平性为主要约束,构建一种适用于多水源、多子区、多用户的考虑供需水不确定性的多目标模糊规划模型,以期通过平衡水资源配置系统中用户配置水量、缺水风险与系统收益三者的关系,实现系统综合效益最大。模型以衡水市历年供水、用水及社会经济等数据确定规划年的水资源参数及经济参数,采用区间参数反映系统中的不确定性,通过引入模糊隶属度函数,利用两步交互式算法,将多目标规划转化为单目标规划进行求解,以2025年为衡水市规划水平年,得到规划水平年下的11个子区、4种水源、4个用水行业的最优配水方案。结果表明：本研究制定的水资源优化配置方案可实现“外调水优先利用、地下水控制利用”,同时考虑用水的公平性约束后,在缺水条件下可有效控制水资源向每立方米水效益高的区域和部门流动,有利于多区域、多部门共担缺水风险;该水资源优化配置方案可有效缓解衡水市水资源供需矛盾,实现多水源和多目标之间的协同互补。研究成果可为河北省其他县域的水资源优化配置提供技术参...     

Pricing and Water Resource Allocation Scheme for the South-to-North Water Diversion Project in China

The eastern route of the South-to-North Water Diversion (SNWD-ER) project is a massive-scale interbasin system to transfer water from the Yangtze River to North China. With the infrastructure construction close to completion, the project is now faced with many complicated operations management problem at different levels. The problems are unique in that, on the one hand, the project is expected to be financially self-sustainable by charging water usages, and on the other hand, the water price is regulated for its nature as a social product. One such problem is to achieve a rational water allocation among different users by appropriate pricing schemes. In this paper, we study how to use a two-tier pricing scheme to balance the water allocation by using a Stackelberg game model. From the study, we find that (1) the Stackelberg game always has equilibrium solutions to balance the benefit of every party in the system, which implies that the two-tier pricing scheme can effectively coordinate the water allocation; (2) the two-tier pricing scheme can also result in multiple desirable by-products such as encouraging the implementation of water saving mechanism and giving the local water users certain priority; and (3) the government can adjust the pricing parameters to control and balance the profit of every party. As such we conclude that the two-tier pricing scheme is an effective way that integrates both the government control and market powers to ensure the public interest and the economic benefit, which is suitable for SNWD-ER project.     

Development of a Long-term, Ecologically Oriented Dam Release Plan for the Lake Baiyangdian Sub-basin, Northern China

Using China’s Lake Baiyangdian sub-basin for a case study, we developed an ecologically oriented dam release plan that can be used to define an optimal dam operation scheme that provides both the environmental flows required by bodies of water and wetlands downstream from the Xidayang Reservoir dam and enough water for agricultural, and industrial water users. In addition, we evaluated the benefits that might be provided by modifying releases of water from the reservoir. To attain ecological sustainability in the sub-basin, we used the supply for each water user as a decision variable based on three objectives: (1) to achieve sustainable socioeconomic development; (2) to keep the water volume as close as possible to the ideal environmental flows in the urban rivers of Baoding City; and (3) to keep the water amount as close as possible to Lake Baiyangdian’s ideal environmental water requirements. We used the ideal-point method to provide dimensionless values for the first objective, and then used a weighting method to integrate the three objectives into a single holistic goal. We then used the GAMS/CONOPT software to solve the nonlinear model and predict the optimal results. We discuss the optimal water allocation and ecologically oriented dam release plans for the three scenarios. To determine the limitations of the method, we performed a sensitivity analysis, and discuss the optimal results for different weightings of objectives provided by decision-makers. The results of the optimization analysis provide a set of effective compromises among the target objectives that can guide future management of water releases from the reservoir.     

Asymmetry and Equity in Water Resources Management; Critical Institutional Issues for Southern Africa

Water users wish to achieve the highest benefits from water resources. Rules limit the manner in which water users may utilise the water resources occurring within their constituencies or territories. However an asymmetrical situation exists whereby downstream users may not affect upstream users but upstream users do cause downstream impacts. Because of this asymmetry the equitable sharing of water resources between upstream and downstream users will always imply that upstream users have to forego some potential water benefits. The general question that this paper addresses is: which institutional arrangements can be devised to (re-)establish an equilibrium between up- and downstream entities within a catchment area or river basin? The paper addresses this question by first focusing on some local and national water allocation arrangements. After briefly reviewing the different management regimes, customary and colonial, that co-evolved in Southern Africa, it assesses the water management principles that are currently being espoused. The focus then turns to the principles in international water law that deal with the allocation of water in transboundary river basins. It is concluded that it often proves difficult to reach agreement over how to share the scarce resource. The paper then discusses the current trend to look beyond water and beyond the river basin when seeking peaceful means to share a common water resource. The concept of “hydrosolidarity” emerges as a normative value that may help to recreate a balance between the various (asymmetrical) interests that exist within a river basin. The paper concludes that water resources can only be governed wisely is there is capacity to understand and monitor the water fluxes within a river basin. If such capacity is wanting, priority should be given to strengthen it.     

基于生态补偿的用水户水权交易价格研究

用水户间水权交易是实现区域水资源优化分配的有效途径。针对同一区域内不同行业用水户之间水权交易价格的制定及生态补偿机制问题开展研究,提出反映不同行业污染程度的用水户水权交易价格调整系数,并将其作为水权交易生态补偿主要因子,纳入到水权交易定价模型中,探索用水户间水权交易的生态补偿机制。     

A Conditional Value-at-Risk Based Inexact Water Allocation Model

A conditional value-at-risk (CVaR) based inexact two-stage stochastic programming (CITSP) model was developed in this study for supporting water resources allocation problems under uncertainty. A CITSP model was formulated through incorporating a CVaR constraint into an inexact two-stage stochastic programming (ITSP) framework, and could be used to deal with uncertainties expressed as not only probability distributions but also discrete intervals. The measure of risks about the second-stage penalty cost was incorporated into the model, such that the trade-off between system economy and extreme expected loss could be analyzed. The developed model was applied to a water resources allocation problem involving a reservoir and three competing water users. The results indicated that the CITSP model performed better than the ITSP model in its capability of reflecting the economic loss from extreme events. Also, it could generate interval solutions within which the decision alternatives could be selected from a flexible decision space. Overall, the CITSP model was useful for reflecting the decision maker’s attitude toward risk aversion and could help seek cost-effective water resources management strategies under complex uncertainties.     

Optimal planning of water supply system for long-term sustainability

Developing a long-term system plan for sustainable water supply is a challenging task due to system complexity and future uncertainties in water demands and source availability. Here a coupled optimization model is proposed for water supply system design and long-term operations by deciding system component sizes and water flow allocations simultaneously. The objective is to minimize overall system costs (i.e., sum of capital and operation costs) while meeting water demands and operational constraints. The economic costs include initial component construction costs and operation expenditure over pre-defined operation years. The proposed model integrates a genetic algorithm with a linear programming model to optimize water infrastructure investments and annual water transfers satisfying flow constraints. The coupled model was applied to a simplified water supply network composed of multiple water sources and users. For the application network, various qualities of water from different sources could be supplied to different users. Plausible future scenarios with time varying water demands were simulated representing potential future conditions. Application results show that the proposed coupled model is beneficial in decision making process to design structural components in near future and prepare long-term policies for water shortage and water right issues in upcoming years. The model can be tailored to a specific system and various regulations and conditions can be incorporated within the model without adding complexity to the optimization framework.     

A Decision Support System to Improve Water Resources Management in the Conchos Basin

The Conchos basin is the largest tributary to the lower part of the Rio Grande/Rio Bravo basin. During recent years a severe drought has affected México’s ability to deliver water from the Conchos basin as required by the 1944 Treaty. In addition, it has generated not only economic problems in the USA and México but also political frictions between these two countries. The Mexican Conchos river has historically contributed with the highest amount of water to USA as established on the water treaty. A Decision Support System (DSS) was developed for the Conchos basin in order to gain a better understanding of the water resources management process in the basin, and to identify the alternatives to improve the cited process. The DSS is a semi-distributed model, based on System Dynamics, and developed using Powersim software. The DSS has been used to evaluate 25 long and short tem water resources allocation alternatives for the two main basin’s users: Irrigation Districts and Water Treaty. Some of the most important factors being tested on the 25 water management alternatives include National Commission of Water’s yearly water allocation policy, reservoir operation rules, improvement on water distribution efficiencies, etc. The DSS model shows that the historic water resources allocation implemented by the Federal government produces adequate results as compared with the other tested water management alternatives. However, for short term drought scenarios, it is showed that there could be other management alternatives that could perform better than the current water management allocation. In general, the DSS shows what we already expect of dynamic models of systems to provide that understanding the effects of multiple interacting variables in necessary to develop good natural resource management policies.