Towards Sustainable Cities: Studying Evaluation Index of Water Environment Carrying Capacity

Water is a crucial resource for sustainable development in cites. Water carrying capacity is a vital part of the carrying capacity of various natural resources in the sustainable development of a region. Appropriately assessing water environment carrying capacity (WECC) is crucial for wise water resources management and economic and social progress advancement. This study developed a WECC evaluation index system for Suzhou, a representative city in southeastern China facing water quality challenges, with the city being an example to study the WECC in the Yangtze River Delta region. By employing principal component analysis (PCA), 20 WECC-related variables were selected from the water and environment, human society, and socio-economic system as the local WECC evaluation indicators. These indicators were weighted by PCA analysis and the entropy method, resulting in overall scores. Evaluating the data from 2001 to 2021, this study showed that the overall WECC score has increased over time. Factors such as rapid urbanization, population growth, economic and social development, and a shortage of water supply have strained the WECC in Suzhou. As an important industrial development zone in the Yangtze River Delta, the city faces significant environmental pollution and water resources problems. The results show that the primary influencing factors are total water resources, surface water resources, water consumption, urbanization rate, water consumption per 10,000 yuan of GDP, industrial value-added water consumption, and chemical oxygen demand (COD) emissions of GDP. The findings of this study help to plan the city's future development and thereby contribute to urban sustainability.