Comprehensive Evaluation of Water Eco-environment and Regional Differences in Yangtze River Economic Belt

Abstract

[Objective] The state of the water ecological environment in the Yangtze River Economic Belt was evaluated in order to provide a scientific basis for the formulation of ecological protection policies in the region. [Methods] Based on the DCSM model and qualitative analysis, 22 water ecological environment indicators were selected which included the four subsystems of driving force, carrying source, state, and management. By using random forest dimensionality reduction, 12 highly correlated indicators were identified as a comprehensive evaluation system. The water ecological environment of 11 provinces in the Yangtze River Economic Belt was ranked from 2010 to 2019 by combining the weighted rank sum ratio model and the adversarial interpretative structure model. The ranking was determined according to the degree of superiority and inferiority. [Results] ① In general, the water ecological environment of the Yangtze River Economic Belt differed significantly among regions, showing an asymmetric U-shaped distribution with the downstream region being superior, the upstream region being second, and the midstream region being worst. ② In terms of spatial distribution, the water ecological status of Zhejiang Province ranked first, while that of Jiangsu, Yunnan, Guizhou, Anhui, Jiangxi, Sichuan Province, Chongqing City, and Hubei Province decreased in a "steplike" descending manner, and that of Hunan Province and Shanghai City ranked low. ③ In terms of classification indexes, industrial wastewater reuse rate, water consumption of 10 000 yuan of agricultural GDP, and wastewater discharge of 10 000 yuan of industrial value added had significant impacts on the water ecological environment. [Conclusion] The overall water ecological environment of the Yangtze River Economic Belt has still not reached a safe and stable state. Improving the quality of the water ecological environment from various aspects according to local conditions is an important driving force for promoting high-level sustainable development of the Yangtze River Economic Belt.

Keywords

• water ecological environment
• random forest
• weighted rank sum ratio
• adversarial interpretive structure model
• yangtze river economic belt