南京市水环境承载力情景预测研究

了解区域水环境承载力未来发展状况,有助于支撑区域生态文明建设。以南京市为研究区域,构建基于社会经济-水资源-水环境复合系统的水环境承载力指标体系,建立区域适用的系统动力学模型,设计未来发展的6种可能情景;在此基础上,将遗传算法用于投影寻踪优化,构建遗传投影寻踪方法,预测2017—2030年不同发展方案下的水环境承载力。结果表明:2017—2030年各方案下南京市水环境承载力均呈上升趋势,各方案对水环境承载力的提升效果表现为综合方案(30.1%)>节水方案(28.5%)>水污染治理方案(24.2%)>经济优化方案(24.0%)>原始方案(21.3%)>人口增长方案(12.5%)。原始方案中水环境承载力稳步提升,2027年开始超过Ⅰ级,即在现状发展模式下,南京市社会经济发展的规模处于水环境承载力可支撑的规模范围内;综合方案下,水环境承载力最快达到Ⅰ级;人口增长方案下,水环境承载力发展水平显著受阻,在预测期内始终未达到Ⅰ级。南京市若采取人口增长、经济优化、水资源节约与水污染治理协同发展模式,其水环境承载力将会快速提升。

Scenario analysis and forecasts of water environment carrying capacity in Nanjing City

The study of future development of regional water environment carrying capacity (WECC) is necessary to support the construction of regional ecological civilization. Taking Nanjing City as an example, a three dimensional indicator system of WECC based on the composite system of socioeconomic, water resources and water environment was established. A regionally applicable system dynamics model and six development scenarios were also designed. On this basis, the genetic algorithm was applied to projection pursuit optimization, and the genetic projection pursuit method was constructed to predict WECC under different scenarios in 2017-2030. The study showed that the WECC of Nanjing was increasing under each of the scenarios in 2017-2030, and the performance of promoting WECC was: comprehensive development scheme (30.1%) > water saving scheme (28.5%) > water pollution control scheme (24.2%) > economic optimization scheme (24.0%) > current pattern scheme (21.3%) > high population growth scheme (12.5%). Under the current pattern scheme, the WECC of Nanjing would be steadily improved, and exceed Level Ⅰ by 2027. This is to say, under the current development mode, the scale of Nanjing’s socio-economic development would be within the scale that could be supported by the water environment. The WECC under the comprehensive scheme was the fastest to reach Level Ⅰ. Under the high population growth scheme, the development level of WECC would be significantly hindered, and never reach Level Ⅰ during the study period. If Nanjing City adopted the model of population growth, economic optimization, water resource conservation and water pollution control, WECC would be improved faster.