南京市水环境承载力动态变化研究

为揭示区域水环境承载力动态变化特征，以南京市为例，从社会经济、水资源和水生态环境3个子系统选取18个指标，构建水环境承载力评价指标体系并确定各指标权重，利用模糊综合评价模型对水环境承载力进行评价，并通过障碍度模型诊断影响水环境承载力的障碍因素.结果表明:①2006-2016年南京市水环境承载力综合评分值从0.345 0增至0.470 0，整体呈上升趋势.②子系统评分值差异较大.水生态环境子系统评分值波动起伏但总体水平较高，年均评分值为0.615 1；社会经济子系统评分值从0.427 6逐年增至0.635 6.二者为承载力的提升奠定了基础.水资源子系统评分值低于0.200 0，极大地制约了南京市水环境承载力的发展水平.③从障碍度分析来看，人口密度、水资源开发利用率、人均水资源量及水功能区水质达标率是水环境承载力的主要障碍因素；就子系统而言，水资源子系统的障碍作用最为显著.研究显示，人口密度偏大、水资源供需矛盾及水功能区水质达标率偏低等是制约南京市水环境承载力的关键因素，也是提升南京市水环境承载力的重点. 

Dynamic Change of Water Environment Carrying Capacity in Nanjing City

To reveal dynamic characteristics of regional water environment carrying capacity, this study designed an indicator system consisting of three subsystems (socioeconomic subsystem, water resource subsystem and water eco-environment subsystem), and determined the weights of indicators. Fuzzy comprehensive assessment model was used to map out the dynamic trend of water environment carrying capacity. Obstacle degree model was used to analyze the obstacle factors. The results showed that:(1) The water environment carrying capacity steadily increased from 0.3450 in 2006 to 0.4700 in 2016. (2) There were great differences among the subsystems. The evaluation index of the water eco-environment subsystems reached more than 0.6151 with some fluctuations, and the economic subsystem increased from 0.4276 to 0.6356, which laid a solid foundation for the improvement of water environment carrying capacity. The water resource subsystem, with evaluation index lower than 0.2000, was found to be the top factor impacting water environment carrying capacity. (3) According to the analysis of obstacle degree, the factors with higher obstacle degrees were the population density, water resource utilization rate, per capita water resources, and water quality compliance rate. The water resource subsystem was the dominant factor that influenced the water environment carrying capacity. The primary challenges to improve the water environment carrying capacity are dense population and low compliance rate of water quality. Attention should be paid to these factors when improving the water environment carrying capacity in Nanjing City.