Dynamic Evaluation of Sustainable Water Resource Systems in Metropolitan Areas: A Case Study of the Beijing Megacity

Comprehensive evaluation of water ecological environment in watersheds: a case study of the Yangtze River Economic Belt, China

The Yangtze River Economic Belt, an inland economic zone with global influence, has shown a trend of prosperous economic development in recent years. Economic development, water pollution, resource depletion, and other environmental problems continue to emerge. The steady state of the water ecological environment is an important aspect of ecological security. To investigate the regional water ecological security state, this study constructs a comprehensive evaluation indicator system within the framework of "driving force-carrying source-state-management" (DCSM). The entropy weight method was used to determine the weight of each indicator, and the weighted rank sum ratio model was introduced to classify the water ecological environment of the Yangtze River Economic Belt from 2010 to 2019. Finally, an adversarial interpretative structure model is used to refine the ranking of each region. The results show that the bearing state and driving force subsystems are closely related to the water ecological environment. The top three indicators are wastewater discharge of industrial added value of 10,000 yuan, water consumption per 10,000 yuan of industrial gross product, and water consumption per 10,000 yuan of tertiary gross domestic product. In addition, there are clear differences in the water ecological environment of the Yangtze River Economic Belt. The classification results show that Zhejiang and Jiangsu are rated as "excellent''; Yunnan, Guizhou, Anhui, and Jiangxi are in the "good" level; and Sichuan, Hunan, Chongqing, and Hubei are in the "medium" level. Shanghai is "poor." As a whole, the downstream is superior, the upstream is second, and the midstream is poor in an asymmetric "U"-shaped distribution. During the study period, the overall state of water ecology in the Yangtze River Economic Belt was at a medium level and has not yet reached a safe and steady state. The performance of areas with traditional industrialization as the main development path was poor. Therefore, it is necessary to pay attention to the overall water ecological security in the basin in the future, strengthen the regulatory role of the government's water ecological management, promote reform of traditional industries and resource-based regions, and achieve the sustainable development of the water ecological environment.

Study and Application of Urban Aquatic Ecosystem Health Evaluation Index System in River Network Plain Area

The evaluation index system of urban aquatic ecosystem health is of great significance for the assessment and management of urban river networks, and for urban development planning. In this paper, the concept of urban aquatic ecosystem health was analyzed by the relationship between human, city and aquatic ecosystem, and its evaluation index system was established from environmental conditions, ecological construction, and social service. In addition, the weight value of each index was calculated by the analytic hierarchy process, and the grading standard of each index was set. Jiading New City, a typical city of the river network plain area in Yangtze River delta, was selected as the aquatic ecosystem health evaluation sample. The fuzzy comprehensive method was used to evaluate the aquatic ecosystem health of Jiading New City. The results indicated that the water ecosystem health of Jiading New City reached the "good" level. For the criterion level, environmental conditions and ecological construction reached the "good" level, and social services reached the "excellent" level. For the indicator level, most indicators reached "good" and "excellent" levels, but the river complexity and benthic macroinvertebrate diversity are still in the "poor" state, which indicates that the aquatic environment has greatly improved, but the aquatic ecosystem has not been fully restored. Results suggested that river complexity and biodiversity should be increased in urban construction planning. The evaluation index system established in this paper can be used to reflect the urban aquatic ecosystem health conditions in river network plain areas.