Regional Water Use Structure Optimization Under Multiple Uncertainties Based on Water Resources Vulnerability Analysis

In this paper, a modeling framework by combining system dynamic (SD) model and optimal allocation model was developed to study water resources vulnerability and optimal water use structure, and the framework was applied in the middle reaches of Heihe River basin, northwest of China. The SD model could describe the dynamical change of water resources vulnerability by integrating water resources with socio-economic effect. The sensitivity analysis of SD model was then conducted to design appropriate scenarios for finding out the optimal development pattern, and based on which, an integrated water-saving scenario with lower water resources vulnerability was identified for optimization modeling. Then, an inexact fuzzy-parameter two-stage programming (IFTSP) model was developed and applied to optimize water use structure among industries under uncertainties. This study addresses the water resources vulnerability analysis in considering both water resources system and socio-economic system. Water resources vulnerability analysis was combined with optimization model to make adaptive water resources management plans. And the optimal allocation schemes under lower water resources vulnerability are more advantageous for regional sustainable development.     

缺水型大城市多水源调配管理技术体系与方法研究

针对缺水型大城市多水源供水系统日益庞杂带来的规范化和精细化调配管理问题,通过强化最严格水资源管理制度对城市多水源统一调配和管理的指导作用,从前期调配评估、调配系统构建、调度规程制定、调配方案编制四方面,探讨了缺水型大城市多水源调配管理技术体系,提出了城市水源-工程-单位-用户四层供水系统网络拓扑结构、城市供用耗排水量流转关系、水资源调配工程与管理体系、水资源日常调度规程、多水源联合调度模型等关键技术问题的解决思路与方法。将该技术体系应用于北京市水资源统一调配管理,结果表明:北京市供水系统可划分为4类水源-11类供水工程-4大水管系统-5大用户的网络拓扑结构。在此基础上,可构建由36家机关单位组成的水资源三级调度管理体系,按照调度会商-决策-实施-调整为核心的调度流程,依据统筹用水管控、水源配置、水量调度原则编制的水量调配方案开展日常水量调度工作。研究成果可为水行政主管部门推进水资源精细化调配管理工作提供技术支撑。     

IFTSQP: An Inexact Optimization Model for Water Resources Management under Uncertainty

Abstract

An interval-fuzzy two-stage quadratic programming (IFTSQP) method is developed for water resources management under uncertainty. The methodincorporates techniques of interval-parameter programming, two-stage stochastic programming, and fuzzy quadratic programming within a general optimization framework to tackle multiple uncertainties presented as intervals, fuzzy sets and probability distributions. In the model formulation, multiple control variables are adopted to handle independent uncertainties in the model's right-hand sides; fuzzy quadratic terms are used in the objective function to minimize the variation in satisfaction degrees among the constraints. Moreover, the method can support the analysis of policy scenarios that are associated with economic penalties when the promised targets are violated. The developed method is then applied to a case study of water resources management planning. The results indicate that reasonable solutions have been obtained. They can help provide bases for identifying desired water-allocation plans with a maximized system benefit and a minimized constraint-violation risk.     

Agricultural Multi-Water Source Allocation Model Based on Interval Two-Stage Stochastic Robust Programming under Uncertainty

Numerous uncertainties and complexities exist in the agricultural irrigation water allocation system, that must be considered in the optimization of water resources allocation. In this paper, an agricultural multi-water source allocation model, consisting of stochastic robust programming and two-stage random programming and introducing interval numbers and random variables to represent the uncertainties, was proposed for the optimization of irrigation water allocation in Jiamusi City of Heilongjiang Province, China. The model could optimize the water allocaton to different crops of groundwater and surface water. Then, the optimal target value and the optimal water allocation of different water sources distributed to different crops could be obtained. The model optimized the economic benefits and stability of the agricultural irrigation water allocation system via the introduction of a the penalty cost variable measurement to the objective function. The results revealed that the total water shortage changed from [18.6, 32.3]?×?10⁸ m³ to [15.7, 26.2]?×?10⁸ m³ at a risk level ω from zero to five, indicating that the water shortage decreased and the reliability improved in the agricultural irrigation water allocation system. Additionally, the net economic benefits of irrigation changed from [287.21, 357.86]?×?10⁸ yuan to [253.23, 301.32]?×?10⁸ yuan, indicating that the economic benefit difference was reduced. Therefore, the model can be used by decision makers to develop appropriate water distribution schemes based on the rational consideration of the economic benefit, stability and risk of the agricultural irrigation water allocation system.     

Interval-parameter Two-stage Stochastic Nonlinear Programming for Water Resources Management under Uncertainty

Over the past decades, controversial and conflict-laden water allocation issues among competing interests have raised increasing concerns. In this research, an interval-parameter two-stage stochastic nonlinear programming (ITNP) method is developed for supporting decisions of water-resources allocation within a multi-reservoir system. The ITNP can handle uncertainties expressed as both probability distributions and discrete intervals. It can also be used for analyzing various policy scenarios that are associated with different levels of economic consequences when the promised allocation targets are violated. Moreover, it can deal with nonlinearities in the objective function such that the economies-of-scale effects in the stochastic program can be quantified. The proposed method is applied to a case study of water-resources allocation within a multi-user, multi-region and multi-reservoir context for demonstrating its applicability. The results indicate that reasonable solutions have been generated, which present as combined interval and distributional information. They provide desired water allocation plans with a maximized economic benefit and a minimized system-disruption risk. The results also demonstrate that a proper policy for water allocation can help not only mitigate the penalty due to insufficient supply but also reduce the waste of water resources.     

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.     

协调模式下的吐鲁番地区水资源合理供求模式分析

系统动力学基于系统理论,能够将用水子系统和供水子系统纳入到水资源供需系统中,并且可以分析每个子系统中各因素的变化对于整体系统的影响.而系统动力学软件Stella可以通过情景模拟来预测水资源供需的发展趋势.运用系统动力学的方法,结合吐鲁番社会经济发展和生态需水的实际情况,构建了吐鲁番水资源供需系统模型,设定四种不同的情景,仿真模拟了2013年-2030年吐鲁番地区水资源供需变化趋势,进而对该地区水资源供需平衡进行分析.研究结果表明:为实现水资源的优化利用,保证吐鲁番地区的可持续发展,还必须加大水利建设,增加水利投资,进一步实施节水措施,巧妙合理的利用水资源.     

An Inexact Two-stage Fuzzy-stochastic Programming Model for Water Resources Management

An inexact two-stage fuzzy-stochastic programming (ITFSP) method is developed for water resources management under uncertainty. Fuzzy sets theory is introduced to represent various punishment policies under different water availability conditions. As an extension of conventional two-stage stochastic programming (TSP) method, two special characteristics of the proposed approach make it unique compared with existing approaches. One is it could handle flexible penalty rates, which are much reasonable for both of the authorities and users, and have seldom been considered in the TSP framework. The other is uncertain information expressed as discrete intervals and probability distribution functions can be effectively reflected in the optimization processes and solutions. After formulating the model, a hypothetical case is employed for demonstrating its applicability under two scenarios, where the inflow is divided into four and eight intervals, respectively. The results indicate that reasonable solutions have been obtained. They provide desired allocation patterns with maximized system benefit under two feasibility levels. The solutions present as stable intervals with different risk levels in violating the water demands, and can be used for generating decision alternatives. Comparisons of the solution from the ITFSP with that from the ITSP (inexact two-stage stochastic programming) and TSP approach are also undertaken. It shows that the ITFSP could produce more system benefit than existing methods and deal with flexible penalty policies for better water management and utilization.     

基于规则的水资源配置模型应用研究

为了将多层次、多工程、多用户、多水源的复杂水资源配置系统转换成计算机模型,合理有效地模拟水资源系统,进而完成区域或流域水资源从多水源向多用户的水量分配过程,着重介绍了水资源系统的系统概化规则和模型配置规则,在此基础上提出了基于规则的水资源配置模型,并将该模型应用在滹沱河流域.应用结果表明,模型的构建合理可行,规则的确定切合实际,模拟计算的结果合理可靠,该模型具有良好的实用性.     

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.

     

Interval-parameter Two-stage Stochastic Semi-infinite Programming: Application to Water Resources Management under Uncertainty

In this study, an interval-parameter two-stage stochastic semi-infinite programming (ITSSP) method was developed for water resources management under uncertainty. As a new extension of mathematical programming methods, the developed ITSSP approach has advantages in uncertainty reflection and policy analysis. In order to better account for uncertainties, the ITSSP approach is expressed with discrete intervals, functional intervals and probability density functions. The ITSSP method integrates the two-stage stochastic programming (TSP), interval programming (IP) and semi-infinite programming (SIP) within a general optimization framework. The ITSSP has an infinite number of constraints because it uses functional intervals with time (t) being an independent variable. The different t values within the range [0, 90] lead to different constraints. At same time, ITSSP also includes probability distribution information. The ITSSP method can incorporate pre-defined water resource management policies directly into its optimization process to analyze various policy scenarios having different economic penalties when the promised amounts are not delivered. The model is applied to a water resource management system with three users and four periods (corresponding to winter, spring, summer and fall, respectively). Solutions of the ITSSP model provide desired water allocation patterns, which maximize both the system’s benefits and feasibility. The results indicate that reasonable interval solutions were generated for objective function values and decision variables, thus a number of decision alternatives can be generated under different levels of stream flow. The obtained solutions are useful for decision makers to obtain insight regarding the tradeoffs between environmental, economic and system reliability criteria.     

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.     

An integrated population,economic, and water resource model to address sustainable development questions for Botswana

Abstract:

An integrated population, economic, and water resource model was developed to address sustainable development questions for Botswana. raditionally, water resources planning models have considered the implications of different assumptions of population and economic growth on the sustainability of existing water resources supply; however, this model extends that capability to consider feedbacks from one model component to another. For example, the model has the unique capability to examine implications of changing water‐related diarrhea incidence on the health of the HIV/AIDS population. Investments in water supply and sanitation or in HIV/AIDS medication impact the health and productivity of the population. The water model uses a physically‐based hydrologic rainfall‐runoff model with surface and groundwater components to produce monthly runoff and groundwater recharge at the watershed scale. Botswana is divided into socioeconomic regions, and the water resources infrastructure is characterized by virtual reservoirs in each. The demographic sub‐model is a standard multi‐cohort model that forecasts the population by age, sex, rural or urban residence, education level, and HIV/AIDS status. The economic sub‐model is a computable general equilibrium model with three components: agriculture, non‐agricultural exports, and non‐tradables. The model runs an ensemble of scenarios, including climate change, HIV/AIDS, health, economic, and water conservation scenarios, whose output is probabilistic in nature. The three model components are described, with particular emphasis on the model linkages and the water sub‐component, and results are shown for a variety of scenarios.     

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.     

漳卫南灌区农业水资源优化配置研究

考虑到不确定条件下漳卫南灌区农业水资源管理的复杂性,为了解决当灌区水资源用户供水目标不能满足需求时的水资源优化配置问题,结合LFP模型与TSP模型的优点,开发了一种分式两阶段随机规划模型(FTSP)。选择漳卫南灌区最大控制性工程岳城水库的两个大型供水灌区作为验证实例,模型应用结果表明,不同决策情景所对应的经济效益和缺水风险不同,最优决策实现了经济效益和缺水风险之间的平衡;不同径流水平下,各用户的正常灌溉面积会发生相应变化,高径流水平时所有用户均能得到正常灌溉。     

基于多目标不确定性机会约束规划的矿区水资源配置研究

以矿区水资源配置系统为研究对象,针对矿区生态恢复过程水资源配置的多目标、模糊、不确定性的特点,构建多目标不确定性机会约束规划模型对矿区水资源进行优化配置。基于生态优先的配水原则,以碳排放最小化目标代替传统的污染物排放量最小化目标,兼顾碳排放最小化、系统经济效益最大化以及缺水量最小化,建立矿区生态环境-经济社会-水资源协调发展的多目标模型,统筹分配地下水、地表水、矿井水以及再生水。对实际情况中的不确定性因素采用区间参数的方法表示,并通过遗传算法对模型进行求解,得到合理的水资源配置方案。将模型应用于宁夏回族自治区羊场湾矿区,结果表明：以碳排放为目标的不确定性机会约束规划多目标模型能够很好地统筹矿区经济发展目标与水资源节约目标,配置方案可保证各个用水部门的需水满足度达到100%,而以污染物排放量为目标的优化方案存在区域缺水的情况。系统可带来年碳净吸收量(CO₂)为533.7～702.4 t,预期年经济效益为162.3×10⁴～163.7×10⁴元,区域年供水富余量为43.5×10⁴～49.7×10     

Optimization of Industrial Structure Considering the Uncertainty of Water Resources

This paper developed a stochastic linear fractional programming model for industry optimization allocation base on the uncertainty of water resources incorporating chance constrained programming and fractional programming. In this paper, the stochastic linear fractional programming is used in the real word. The development SLFP has the following advantages: (1) The model can compare the two aspects of the targets; (2) The model can reflect the system efficiency intuitively; (3) The model can deal with uncertain issues with probability distribution; (4) The model can give different optimal plans under different risk conditions. The model has a significant value for the industry optimization allocation under uncertainty in local and areas to achieve the maximum economic benefits and the full use of the water resources.     

基于宏观经济模型和系统动力学的张掖盆地水资源供需研究

针对黑河流域中游张掖盆地水资源供需问题,采用宏观经济模型和系统动力学结合的方法,构建了张掖盆地水资源系统动力学模型,设计5个情景模拟张掖盆地2013-2050年水资源供需平衡状况。结果表明:宏观经济模型与系统动力学的结合能更好地刻画系统行为,准确合理地预测需水量;预测期内张掖盆地需水量逐年增长,年均总需水量为21.87×108~30.14×108m3,缺水年的年均缺水量为4.03×108~7.64×108m3,缺水时间占比为31.6%~92.1%,缺水年平均缺水指数为0.1413~0.2217;综合考虑社会经济发展、城镇化和水资源节约的情景S5是最符合可持续发展内涵和原则的情景;水资源的可持续发展,不仅需要政府的政策引导,更需要公众的参与,只有政府与公众的协调一致,才能保证水资源和社会经济的可持续发展。     

基于鲁棒规划方法的农业水资源多目标优化配置模型

在干旱半干旱地区,调整种植结构可以促进农业水资源的高效利用。农业水资源配置需要在多个目标间权衡博弈,对各目标的偏好和赋权直接影响着优化模型的输出和决策方案的制定,但以往研究往往忽略了权重确定过程中因主观等因素的影响而普遍存在的不确定性。针对农业水资源多目标规划中存在的权重不确定性难题,建立了基于鲁棒优化方法的农业水资源多目标优化配置模型方法(MRPWU)。该方法可以把权重中蕴含的复杂不确定性信息纳入建模过程,产生可靠的模型结果;并能提供效益值及风险值均定量化的方案集,便于决策者在权衡效益与风险后确定最优方案。模型以作物种植经济收益和碳吸收量最大化为目标、以水土资源供需平衡等为约束条件,并应用于农业水资源供需矛盾突出的甘肃省民勤县。优化结果表明,随着保护度水平的提高,生态效益上升,经济效益和综合效益下降,系统面临的风险也随之下降。相比于权重为确定参数的模型,MRPWU模型可以在综合效益下降3.7%的同时,较大地提高系统应对权重不确定性以及风险的能力。与2017年的实际情况相比,MRPWU模型可以减少种植面积1.6%、节省灌溉用水3.9%,同时提高生态效益1.6%。     

新疆农六师所在地水资源承载能力研究

分析新疆农六师所在地现状水资源开发利用情况及存在的问题,构建了水资源优化配置模型,通过不同方案长系列逐月调节计算和对比分析,选取中方案为水资源配置推荐方案。同时,采用双指针计算模型计算农六师高、中、低三种需水方案的水资源承载能力,指出现状年105团当地水资源已经处于超载状态,到2030年农六师的经济中心五家渠市也将处于水资源超载边缘,超载度为0.97。最后,探讨了如何提高农六师所在地水资源承载能力的途径,为农六师实现跨越式可持续发展提出建议。