城市多水源联合供水优化配置研究

Research on the Optimal Allocation of Urban Multi-water Source Combined Water Supply

以宁夏银川都市圈城乡东线供水工程及其供水范围为研究对象,建立水资源、经济和环境的多目标数学优化配置模型,通过二代非支配排序遗传算法(NSGA-II)对多目标问题进行求解,采用超体积(HV)指标对不同迭代次数获得的Pareto解集进行收敛性以及分布性评价,综合考虑计算时间以及收敛性和分布性情况,确定以700次迭代得到的Pareto解集作为后续数据分析计算的基础,通过对方案集中各目标值的模糊隶属度进行计算以及对各目标间两两关系进行分析,得到水资源目标与经济目标以及经济目标与环境目标间呈负相关关系,水资源目标与环境目标间呈正相关关系。之后采用二元比较法确定各目标的权重为(0.48、0.32、0.2),采用多目标模糊优选模型对Pareto解集进行筛选,确定优属度最大(u_(i)=0.757)的方案为最优方案,在最优方案下地下水用水量为993.29万m^(3)、地表水用水量为6456.90万m^(3)、经济目标为407.45亿元、环境目标为104.09万kg;此方案可实现水资源的优化配置,为区域决策者在进行水资源分配时提供参考依据。

Taking the Ningxia Yinchuan metropolitan area urban-rural east water supply project and its water supply range as the research object,this paper establishes a multi-objective mathematical optimal allocation model of water resources,economy and environment and solves the multi-objective problem by the non-dominated sorting genetic algorithm-II(NSGA-II).The hypervolume(HV)index is used to evaluate the convergence and distribution of the Pareto solution set obtained at different iterations.Considering the computing time,convergence and distribution,the Pareto solution set obtained at 700 iterations is determined as the basis for subsequent data analysis and calculation.By calculating the fuzzy membership degree of each target value in the scheme set and analyzing the pairwise relationship between each target,it is found that there is a negative correlation between water resources objectives and economic objectives,as well as economic objectives and environmental objectives,and a positive correlation between water resources objectives and environmental objectives.Then,the weight of each objective is determined as(0.48,0.32,0.2)by using the method of two elements contrasting.The multi-objective fuzzy optimization model is used to screen the Pareto solution set,and the scheme with the largest superior genus degree(u_(i)=0.757)is determined as the optimal scheme.Under the optimal scheme,the groundwater consumption is 9932.9 thousand m3,the surface water consumption is 64569.0 thousand m^(3),the economic target is 40.745 billion yuan,and the environmental target is 1040.9 thousand kg.This scheme can realize the optimal allocation of water resources and provide a reference for regional decision makers in water resources allocation.