A Demand Management Based Crop and Irrigation Planning Using the Simulation-Optimization Approach

Coupled simulation-optimization models are useful tools for solving optimum water allocation and crop planning problems. In this study, the optimum crops pattern in the Arayez plain in the Karkheh river basin in Iran is determined by integration of a network flow programming (NFP) based simulation model and the shuffle frog leaping optimization algorithm (SFLA) in the form of a simulation-optimization approach. MODSIM applies NFP for finding water allocations which by use of its customization ability, the benefit of water supply for the agricultural crops is calculated based on the agronomic equations. The objective function is to maximize the total net benefit gained from crops production where the decision variables which are the irrigation depths and the cultivation areas are optimized by SFLA. Results show that by use of the coupled SFLA-NFP model, the net benefit increases 12% comparing the present situation in the plain. Also, the sensitivity analyses on effective parameters indicate that the potential maximum yield and the net price of the crops yield in the market have a direct impact on the crops optimum cultivation area.     

Multi-Objective Differential Evolution-Chaos Shuffled Frog Leaping Algorithm for Water Resources System Optimization

A multi-objective differential evolution-chaos shuffled frog leaping algorithm (MODE-CSFLA) is proposed for water resources system optimization to overcome the shortcomings of easily falling into local minima and premature convergence in SFLA. The performance of MODE-CSFLA in solving benchmark problems is compared with that of non-dominated sorting genetic algorithm II (NSGA-II) and multi-objective particle swarm optimization (MOPSO). At last, the proposed MODE-CSFLA is used to optimize the water resources allocation plan of the East Route of the South-to-North Water Transfer Project in the normal, dry, and extremely dry years. The results reveal that MODE-CSFLA performs better than NSGA-II and MOPSO under all conditions. Compared with shuffled frog leaping algorithm (SFLA), MODE-CSFLA can result in a 29.39, 27.47 and 22.55% increase in water supply when the single objective is to minimize the water pumpage; and a 41.01, 39.63 and 30.94% decrease in total pumpage when the single objective is to maximize the water supply in the normal, dry, and extremely dry conditions, respectively. Thus, MODE-CSFLA has the potential to be used for solving complex optimization problems of water resources systems.     

SFLA-PP模型在区域水资源利用效率综合评价中的应用

为验证混合蛙跳算法(Shuffled Frog Leaping Algorithm,SFLA)-投影寻踪(Projection Pursuit,PP)模型应用于区域水资源利用效率综合评价中的有效性和可行性。从综合、工业、农业、生活和生态环境5个方面遴选15个指标构建区域水资源利用效率评价指标体系,利用SFLA算法优化PP模型最佳投影方向,提出SFLA-PP水资源利用效率评价模型,与构建的入侵杂草优化(Invasive Weed Optimization,IWO)算法、粒子群优化(Particle Swarm Optimization,PSO)算法和布谷鸟搜索(Cuckoo Search,CS)算法优化的PP模型作对比,并基于各模型投影系列均值及标准差σ构造4个等级的水资源利用效率评价标准,以文山州8县市水资源利用效率评价为例进行实例研究。结果表明:SFLA算法优化PP模型获得的适应度值为715.800 2,均优于IWO,PSO和CS算法PP模型,具有较好的求解精度和极值寻优能力;SFLA-PP模型对文山市、砚山县水资源利用效率评价为“高水平”,对麻栗坡县评价为“低水平”,其余5县评价为“中等水平”,全州水资源利用效率综合评价为“较高水平”;SFLA-PP模型对实例评价及排序结果与IWO-PP模型相同;与PSO-PP模型、CS-PP模型在评价结果及排序上均存在差异。实例验证了4种智能算法PP模型的求解精度对区域水资源利用效率的评价结果起到关键作用。     

不确定条件下的多水源联合供水调度模型

本文针对城市供水调度系统中存在的不确定性与复杂性,运用区间两阶段随机规划的方法,建立了多水源联合供水调度的优化模型。该模型以供水调度系统成本最小为目标函数,引入概率分布及区间数表示不确定性,模拟了地表水源、地下水源、外来水源等多种水源联合供水过程,并对多种水源的调水目标进行优化。以区间形式给出优化结果,为决策者提供宽裕的决策空间。利用该方法,可充分考虑系统中不确定因素对系统成本的影响,更真实的反映多水源联合供水系统的实际情况。     

Robust Water Supply Chain Network Design under Uncertainty in Capacity

This paper focuses on the capacity uncertainty in water supply chains that occurs when facilities face disruption. A combination of scenario-based two-stage stochastic programming with the min-max robust optimization approach is proposed to optimize the water supply chain network design problem. In the first stage, the decisions are made on locations and capacities of reservoirs and water-treatment plants while recourse decisions including amount of water extraction, amount of water refinement, and consequently amount of water held in reservoirs are made at the second stage. The proposed robust two-stage stochastic programming model can help decision makers consider the impacts of uncertainties and analyze trade-offs between system cost and stability. The literature reveals that most exact methods are not able to tackle the computational complexity of mixed integer non-linear two-stage stochastic problems at large scale. Another contribution of this study is to propose two metaheuristics - a particle swarm optimization (PSO) and a bat algorithm (BA) - to solve the proposed model in large-scale networks efficiently in a reasonable time. The developed model is applied to several hypothetical cases of water resources management systems to evaluate the effectiveness of the model formulation and solution algorithms. Sensitivity analyses are also carried out to analyze the behavior of the model and the robustness approach under parameters variations.

     

大规模供水系统直接优化调度方法

根据给水系统的网络特性，并结合我国实际情况，对优化调度控制方法进行了系统的分析，建立了优化目标函数及约束方程，针对大规模供水系统特点，提出了直接优化调度实用模型及算法，为满足工程应用要求，采取软化约束条件的措施，达到寻求可行满意解的目的，并改进开发了求解混合离散变量的供水系统直接优化调度软件，进而以我国实际城市为对象，进行了供水系统优化调度的现场实践，证明了其实用性。     

不确定条件下的多水源联合供水调度模型

本文针对城市供水调水系统中存在的不确定性与复杂性，运用区间两阶段随机规划的方法，建立了多水源联合供水调度的优化模型。该模型以供水调度系统成本最小为目标函数，模拟了地表水源、地下水源、外来水源等多种水源联合供水，并对多种水源的调水目标进行优化。以区间形式给出优化结果，为决策者提供宽裕的决策空间。利用该方法，可充分考虑系统中不确定因素对系统成本的影响，更真实的反映多水源联合供水系统的实际情况。     

Water Supply Network Optimisation Using Equal Flow Algorithms

Algorithms to optimise water supply networks are developed and compared when a given set of transfer arcs is constrained to carry the same (or proportional) amounts of flow. Initially, a dynamic multi-period mathematical model is designed as a network flow model. A network simplex-based algorithm, Equalflow, and a subgradient-based algorithm, SUBeqf, are then presented. Both algorithms are characterised by polynomial complexity and can solve large-scale instances that arise when considering water system requirements. A specialised interface for water supply networks provides a data input processor to generate the overall multi-period network model in the implementation of the procedures. The implementation of the algorithms allows the consideration of different types of equal flow instances that take place in water resource system optimisation. The performances of the two algorithms and analysis of their computational efficiency with respect to state-of-the-art mathematical programming software are reported, considering equal-flow instances from a synthetically generated network and two water supply systems in the Sardinia region of Italy.     

Multiperiod Hypergraph Models for Water Systems Optimization

Mathematical models describing water resources systems optimization are characterized by a large number of variables and constraints, which are needed to describe the physical components of the system, its functional ties, and its operating modalities. Some special algebraic structures allow its representation as a pure hypergraph flow problem. The hypergraph structure is derived from a multiperiod network describing the spatial and temporal structure of the physical system. As a crucial feature in modeling functional relations and in describing scenario changes in the system, with the hypergraph approach it is possible to reach a close correspondence between the components of the physical problem and those of the mathematical model. In this paper a water resources management model including a reservoir design problem is studied, and the methodology is tested by the hypergraph simplex algorithm on a real water resources system on the island of Sardinia (Italy) in a extended time horizon. The results obtained show that this technique is very competitive in this kind of problem.     

Increasing Water Security: An Algorithm to Improve Water Distribution Performance

Water Distribution Systems (WDSs) are indispensable infrastructures for urban societies. Due to vitality of continuous supply of drinking water in urban areas, it is necessary to have a performance evaluation and monitoring system to provide the expected level of security in water distribution systems. A main weakness point of these systems is the physical break of pipes which results in high level of water loss, pollution risk and public unsatisfactory. In this study, a framework is developed to increase physical water supply security in urban areas. For this purpose, a physical vulnerability index (PVI) is developed for evaluation of physical statues of water mains. In quantifying PVI, pipe characteristics and bedding soil specifications are considered. The importance of these factors on PVI is determined using Analytical Hierarchy Process (AHP). In system performance evaluation, the pipe role in system performance is incorporated regarding pipe location in WDS, distance of pipe from reservoir and average pressure of pipe. Then, System Physical Performance Index (SPVI) is evaluated. An optimization algorithm is employed to determine ways to improve the system performance through enhancing the physical condition of the pipe in the system at a minimum cost. The genetic algorithm is employed for solving the optimization model. A global sensitivity analysis method named FAST, is used for sensitivity analysis to incorporate the correlation between different parameters in analysis. The proposed framework is applied to a case study located in Tehran metropolitan area. The results of this study show the significant value of the proposed algorithm in supporting decision makers to better choose vulnerable pipes for rehabilitation practices in order to decrease system vulnerability against physical failures.     

山东省提升农村饮水安全水平的成效与实践

山东省多措并举,建管并重,从组织领导、规模化发展、水质安全、基金筹集、管理体制、行业管理等方面入手,大力提升农村饮水安全水平。改变过去农村供水存在的"城乡分割、各自为战"的局面,大力发展规模化集中连片供水。走专业化管理的路子,主要推广自来水公司管理、供水企业管理、乡镇水利站管理三种管理模式。通过落实省政府规章的相关内容、加大检查督导力度、加强人员培训,强化行业管理,提高相关人员的从业水平和能力,为农村供水工程良性运行奠定管理和人才基础。     

多源大型水管网的优化调度

针对多水源的大型供水管网，运用两级递阶优化原理，建立了反映管网各种水力参数的数值仿真模型，运用该数值模型可达如下目的：对不同水源的供水量进行优化配置，并且对某一水源地泵站内水泵的运行进行优化调度，合理利用能源，以取得良好的经济效益和社会效益；通过计算对比，改变旧有管网的管路参数或增删管网内局部支路，为改扩建旧有管网提供科学合理的技术方案。最后以北京地区某大型石化集团的供水系统为实例，给出了计算结果。     

Integrated risk assessment and screening analysis of drinking water safety of a conventional water supply system.

Management of drinking water safety is changing towards an integrated risk assessment and risk management approach that includes all processes in a water supply system from catchment to consumers. However, given the large number of water supply systems in China and the cost of implementing such a risk assessment procedure, there is a necessity to first conduct a strategic screening analysis at a national level. An integrated methodology of risk assessment and screening analysis is thus proposed to evaluate drinking water safety of a conventional water supply system. The violation probability, indicating drinking water safety, is estimated at different locations of a water supply system in terms of permanganate index, ammonia nitrogen, turbidity, residual chlorine and trihalomethanes. Critical parameters with respect to drinking water safety are then identified, based on which an index system is developed to prioritize conventional water supply systems in implementing a detailed risk assessment procedure. The evaluation results are represented as graphic check matrices for the concerned hazards in drinking water, from which the vulnerability of a conventional water supply system is characterized.     

基于最大熵投影寻踪模型的云南省近10 a水资源承载力评价

为对云南省2006—2015年水资源承载力进行评价,从水资源、经济社会和生态系统3个方面提出水资源承载力评价指标体系和分级标准,并基于最大熵投影寻踪(MEPP)技术进行区域水资源承载力评价。采用在指标分级标准阈值间随机生成样本的方法构造MEPP目标函数,利用混合蛙跳算法(SFLA)优化MEPP最佳投影方向,提出SFLA-MEPP水资源承载力评价模型,并构建生物地理优化(BBO)算法-MEPP、和声搜索(HS)算法-MEPP和粒子群优化(PSO)算法-MEPP水资源承载力评价模型作对比模型。结果表明SFLA寻优MEPP目标函数获得的最优值、最劣值、平均值和标准差均优于BBO、HS和PSO算法,具有较好的全局极值寻优能力;SFLA-MEPP模型对云南省2006—2007年、2011—2012年水资源承载力评价为“基本可承载”,其他年份评价为“可承载”;2006—2015年间云南省水资源承载力随时间呈提升趋势,但提升趋势不显著;SFLA-MEPP模型对云南省水资源承载力评价结果与BBO-MEPP模型相同,但在排序上存在差异;与HS-MEPP,PSO-MEPP模型在评价结果及排序上均存在差异。     

Risk Management of Drinking Water Supply in Critical Conditions Using Fuzzy PROMETHEE V Technique

Water crisis management in drinking water supply systems is a crucial issue. Many different natural and unnatural disasters cause great damages to these systems. Prioritizing effective strategies by expert decision-makers before any incidence can greatly reduce this damage. Moreover, cost minimization in the provision of these strategies is very essential as the urban crisis management organizations are financially limited. Therefore, this study provided a model for the selection of the most appropriate drinking water supply strategies in crisis conditions, considering possible limitations. Fuzzy PROMTHEE V, a multi-criteria decision-making method, is a new approach developed in this research to help the decision-makers in selecting a set of possible alternatives for drinking water supply management, which are ranked based on five criteria determined by decision-makers (water supply reliability, implementation speed and simplicity, implementation cost, social satisfaction, water quality) and budget limitation as the constraint for the optimization problem. This model was applied in a case study of Tehran city in Iran. Due to the uncertainties in expert opinions and parameters needed for drinking water supply risk management, this model was solved with three fuzzy methods and one non-fuzzy method, and the results were compared. Findings showed that strengthening passive defense in water supply, transportation, and distribution systems; providing water consumption management; encouraging people to save water for emergency conditions and planning to exploit popular forces and performing maneuvers are top-ranked alternatives.

     

建在半山之上的给水系统-川外新校区生活及消防给水系统设计

四川外语学院新校区建在重庆歌乐山半山之上,采用通过中间转输水箱向高地水池加压供水的方式,改造利用老校区现状供水设施,并修建新校区输水系统.新校区全部采用高地水池供水.由于市政管网不能满足新老校区总的日用水量需要,提出了“日水量差额的调节容积”新概念,确定各个储水池容积和转输泵参数.将新校区生活及消防给水系统合并为一套给水管网,减少管廊占用空间,节省了工程造价；高地水池消防供水是通过开启电动阀和采取一系列措施来保证.     

Basin-wide Water Resources Planning by Integrating PSO Algorithm and MODSIM

Water resources planning and management at basin scale is such a large and complex problem that makes it essential to use effective modeling tools in order to obtain an optimum plan for river basins development. In this paper, a methodology is presented for optimized design and operation of the upstream Sirvan basin in Iran. The model proposed integrates MODSIM generalized river basin network flow model, with the capability of simulating various characteristics and features of water resources in a river basin, and Particle Swarm Optimization (PSO) algorithm. In the developed PSO-MODSIM model, the size of planned dams and water transfer systems, as design variables, and the relative priorities for meeting reservoir target storages, as operational variables, are varied and evolved using PSO algorithm. MODSIM is called to simulate the system performance and to evaluate the fitness of each set of those design and operational variables with respect to the model’s objective function. The PSO objective function is to maximize the total net benefit consisting of benefits due to supplying water to different types of water uses and construction costs of dams and water transfer and/or pumping systems. Varying the design and operational variables in MODSIM 8 is done using the MODSIM’s custom coding feature in VB.NET routine. The PSO-MODSIM model is used to size the planed water storage and transfer components of a river basin system and to allocate water resources optimally over time and space among competing demands, considering coordinated operation of the system components. The model results has been analyzed for different scenarios of water transfer from Sirvan to neighboring basins.     

Selection of Urban Water Supply Systems For Upgrading

ABSTRACT

The Provincial Waterworks Authority of Thailand (PWA) is considering upgrading a number of their water supply schemes to improve the conditions of existing facilities and to maximize the system efficiency with minimum capital expenditures in order to postpone major investments.

The scope of the study was to review all water supply systems managed by PWA to ascertain the need for immediate action, the technical suitability and the cost effectiveness of upgrading and to set priorities among the systems proposed.

After preliminary screening, 39 systems were selected and ranked in accordance with established selection criteria. Specific recommendations were also given for future actions on the selected systems.     

供水系统中经济流速与管径优化节能工程试验研究

针对现有供水系统设计缺陷,研究了基于经济流速的管径优化法,提出了供水系统运行费用、设备费用、管道敷设费用和泵房建设费用及总费用的时间价值.根据使总费用达到最小值的原则,给出了经济流速和管径优化的计算示例和简要说明,并分析了舍维列夫公式和海曾-威廉公式用于镀锌钢管沿程水头损失计算的适用性.     

基于生活、生产和生态环境用水的水资源配置模型

从实际需要出发探讨并给出了水资源系统及水资源配置模型的基本概念和定义;研究了水资源系统网络图的绘制方法;给出了用该图概化和表示系统中的需水、水源、工程以及水的运动等复杂关系的方法;从时间结构和空间结构两个方面介绍了全面考虑生活用水、生产用水和生态环境用水要求的、系统反映各种水源及工程供水特点的水资源配置模型的建模思路和技巧,给出了模型的基本任务和主要约束方程.该模型在河南省安阳市水资源可持续利用综合规划中进行了实际应用,推荐的配置方案合理,计算速度很快.该模型可以应用于大型复杂水资源系统.