An Integrated Approach of System Dynamics,Orthogonal Experimental Design and Inexact Optimization for Supporting Water Resources Management under Uncertainty

An integrated approach of system dynamics (SD), orthogonal experimental design (OED) and inexact optimization modeling was proposed for water resources management under uncertainty. The developed method adopted a combination of SD and OED to identify key scenarios within multiple factors, through which interval solutions for water demands could be obtained as input data for consequential optimization modeling. Also, optimal schemes could be obtained in the combination of inexact two-stage stochastic programming and credibility constrained programming. The developed method was applied to a real-world case study for supporting allocation of multiple-source water resources to multiple users in Dalian city within a multi-year context. The results indicated that a lower credibility-satisfaction level would generate higher allocation efficiency, a higher system benefit and a lower system violation risk. The developed model could successfully reflect and address the variety of uncertainties through provision of credibility levels, which corresponds to the decision makers’ preference regarding the tradeoffs between system benefits and violation risks.     

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     

丰台区水资源耦合配置模型研究

以丰台区水资源配置系统为研究对象,在分析供需水的基础上,构建双层优化模型,其中从环境角度体现对污染物排放量的严格控制,从经济角度体现区域水资源系统经济效益最大化。最终,体现区域水资源数量和质量的统一和不同需水部门之间的合理配置,并达到环境目标和经济目标的集成化。基于模糊满意度算法求解模型,模型结果表明:丰台区各规划水平年的供水量基本上可以满足各用户的需水要求,其中南水北调工程将在区域水资源配置系统中发挥重要作用。进一步地将双层规划模型和两个传统的单目标优化模型的结果进行对比分析,以期为不同决策者提供的规划方案。     

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%。     

Multi-Level Decision-Making for Inter-Regional Water Resources Management with Water Footprint Analysis and Shared Socioeconomic Pathways

This study develops a synergistic optimization framework for planning inter-regional water resources management system under shared socioeconomic pathways; this framework integrates multi-level and robust flexible programs. The upper-level model determines minimum social loss induced by water exploitation, the middle-level one focuses exclusively on pollutant emissions, and the lower-level one aims to achieve maximum economic benefits. An improved multi-level interactive algorithm is proposed to balance the satisfaction degree of constraints and goals to achieve optimal. The effectiveness of the developed multi-level model is illustrated through a real-world case in Wuhan City Circle. Results indicate that the overall water resources performance in Wuhan City Circle is satisfactory, especially in Xianning and Huanggang, whereas some water footprint deficits exist in Wuhan, Xiaogan, and Tianmen. Climate scenarios have a remarkable effect on social loss but only slightly affect water supply strategies, pollutant emissions, and economic benefits. A high satisfactory degree results in a low risk of insufficient water supply and excessive pollutant emissions. Thus, satisfactory degree can be used as an evaluation indicator for identifying the amount of credible and reliable risk on final decisions. The findings of this study can enable stakeholders to grasp the inherent conflicts and trade-offs between environmental and economic interests.

     

基于双层模型的常熟市水资源配置研究

基于水资源优化配置原则,开发出以经济效益为上层目标、以环境效益为下层目标的双层优化模型。通过lingo软件和模糊满意度算法将多目标问题转化为单目标问题求解,对常熟市水资源进行配置。结果表明:2020、2030年区域水资源配置系统经济效益预期分别为24.84×10~8、27.89×10~8元,COD排放量分别为8 342、9 450 t,配水量将分别达到86 228×10~4、93 809×10~4m~3;其中,长江取水占配水总量73%,并且趋势逐渐升高。对比双层优化结果与两个单目标优化结果,可以对决策者提供不同情景下的优化方案。     

基于多层规划的武汉城市圈水量-水质耦合配置研究

以武汉城市圈水资源配置系统为研究对象,在明确水足迹、水承载力及多重水资源需求的基础上,兼顾不同决策目标之间的制衡关系,构建了多层优化模型以达到环境目标、经济目标和社会目标的集成化.上、中、下层模型分别体现了污染物排放量的最小化、系统经济效益的最大化与系统收益配置的均等化.基于一种改进的多层次交互求解算法对模型进行求解,...     

基于两阶段模型的水土资源利用效率评价

传统数据包络分析(DEA)模型应用于水土资源利用效率测算时忽略了系统内部运行机理,根据这一不足,本研究针对水土资源利用的内部复杂性,将水土资源利用过程划分为水土资源开发与经济效益转化两个子阶段,考虑各阶段间关系及投入产出权重结构,构建基于合作博弈思想的两阶段水土资源利用效率测算模型;运用模型测评黑龙江省13个地级市水土资源利用整体及各阶段效率,并构建水土资源利用效率两阶段矩阵图。结果表明,黑龙江省水土资源开发程度整体偏高,但各地级市水土资源经济效益转化不均衡,且水土资源利用整体效率偏低,地区差异较大,水土资源未得到有效的优化配置。该文所构建的DEA模型通过分析影响区域水土资源利用效率的各个环节,可以为决策者提出针对性意见并提供科学依据。     

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.     

中国水资源及水生态安全评价

从水资源及水生态安全的内涵出发,构建了区域水资源及水生态安全评价指标体系。考虑我国的地域状况,根据水资源的丰、平、缺情况和经济水平(发达、欠发达)的6种任意组合,分别筛选评价指标,提出了分区域的评价标准和指标权重。以31个省级行政区为单元,对中国水资源及水生态安全状况进行了评价。结果表明:水资源及水生态状况没有安全的,良好的有10个区,一般的有10个区,较差的有10个区,极差的有1个区。     

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 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.     

Basin Scale Water Resources Systems Modeling Under Cascading Uncertainties

Global change in climate and consequent large impacts on regional hydrologic systems have, in recent years, motivated significant research efforts in water resources modeling under climate change. In an integrated future hydrologic scenario, it is likely that water availability and demands will change significantly due to modifications in hydro-climatic variables such as rainfall, reservoir inflows, temperature, net radiation, wind speed and humidity. An integrated regional water resources management model should capture the likely impacts of climate change on water demands and water availability along with uncertainties associated with climate change impacts and with management goals and objectives under non-stationary conditions. Uncertainties in an integrated regional water resources management model, accumulating from various stages of decision making include climate model and scenario uncertainty in the hydro-climatic impact assessment, uncertainty due to conflicting interests of the water users and uncertainty due to inherent variability of the reservoir inflows. This paper presents an integrated regional water resources management modeling approach considering uncertainties at various stages of decision making by an integration of a hydro-climatic variable projection model, a water demand quantification model, a water quantity management model and a water quality control model. Modeling tools of canonical correlation analysis, stochastic dynamic programming and fuzzy optimization are used in an integrated framework, in the approach presented here. The proposed modeling approach is demonstrated with the case study of the Bhadra Reservoir system in Karnataka, India.     

A Fuzzy-Stochastic Modeling Approach for Multiple Criteria Decision Analysis of Coupled Groundwater-Agricultural Systems

The complexity of water resources management increases when decisions about environmental and social issues are considered in addition to economic efficiency. Such complexities are further compounded by multiple uncertainties about the consequences of potential management decisions. In this paper, a new fuzzy-stochastic multiple criteria decision-making approach is proposed for water resources management in which a variety of criteria in terms of economic, environmental and social dimensions are identified and taken into account. The goal is to evaluate multiple conflicting criteria under uncertainties and to rank a set of management alternatives. The methodology uses a simulation-optimization water management model of a strongly interacting groundwater-agriculture system to enumerate criteria based on these bio-physical process interactions. Fuzzy and/or qualitative information regarding the decision-making process for which quantitative data is not available are evaluated in linguistic terms. Afterwards, Monte Carlo simulation is applied to combine these information and to generate a probabilistic decision matrix of management alternatives versus criteria in an uncertain environment. Based on this outcome, total performance values of the management alternatives are calculated using ordered weighted averaging. The proposed approach is applied to a real world example, where excessive groundwater withdrawal from the coastal aquifer for irrigated agriculture has resulted in saltwater intrusion, threatening the economical basis of farmers and associated societal impacts. The analysis has provided potential decision alternatives which can serve as a platform for negotiation and further exploration. Furthermore, sensitivity of different inputs to resulting rankings is investigated. It is found that decision makers’ risk aversion and risk taking attitude may yield different rankings. The presented approach suits to systematically quantify both probabilistic and fuzzy uncertainties associated with complex hydrosystems management.     

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.     

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.     

城市水资源再生利用系统分析及模拟

运用系统动力学方法,建立了城市水资源再生利用与社会、经济、资源之间相互关系的系统动力学模型(SD模型)。将模型用于西宁市水资源的规划中,通过模型模拟和运行方案,对西宁市水资源再生回用系统的发展趋势进行了中、长期预测。结果表明:随着污水回用的增大,将增大城市供水量,促进城市的经济发展。SD模型能够模拟不同设计方案下系统的发展趋势,为决策者提供理论依据。     

宏观经济水资源规划多目标决策分析方法研究及应用

本文是将区域水资源规划纳入到宏观经济／环境系统中，应用多目标技术进行整体研究，使决策者可通过宏观经济水资源规划多目标决策分析模型的操作和运行，看到在不同策略下区域宏观经济、环境等目标与水资源规划关系的全貌。在该方法研究中，作者完成了这一方法的软件编制和开发工作，实现了决策分析过程的计算机化。     

A Framework for Ground Water Management Based on Bayesian Network and MCDM Techniques

Groundwater resources are steadily subjected to increasing water demands. The aquifers are considered as the most accessible source of fresh water. In recent years, they have been faced with severe water withdrawal in arid and semi-arid countries like Iran and thus some aquifers was considered as forbidden aquifers that it means the water withdrawal from these aquifers is unauthorized. Given a critical situation, groundwater resources management in the form of tools such as monitoring the level of the aquifers and developing the restoring scenarios is essential. Therefore, for this purpose, a framework has been developed based on prediction of groundwater level using Bayesian Networks (BNs) model. Furthermore, Multi Criteria Decision Making methods (MCDM) techniques proposed and employed for ranking of proposed groundwater management scenarios. This framework was evaluated for restoring the Birjand aquifer in Iran in different hydrological conditions. A probabilistic Dynamic BN was proposed for groundwater level prediction under uncertainties. After analyzing the obtained results, the applicable short term scenarios for groundwater management as well as appropriate economic, social and technical criteria were defined for decision making procedure. Then, using elicitation of decision makers’ opinions on the relative importance and performance of criteria, SAW, TOPSIS and PROMETHEE-II techniques were applied to rank the scenarios and the obtained results were aggregated by Borda method for final ranking of the scenarios. Lastly, the final results demonstrates the capability of the proposed framework for groundwater resources planning and management which can be employed for reducing the risk of aquifer level declining.     

天津市水资源多目标优化配置研究

在综合考虑经济、社会、生态、水环境等因素的基础上,建立天津市区域水资源多目标优化模型,利用遗传算法结合理想点法对多目标模型进行求解,在最终对各用水部门给予政策倾斜的前提下,给出不同水资源优化配置方案,以协助决策者制定切实可行的用水方案,实现水资源的可持续发展。