Dynamic simulation and comprehensive evaluation of the water resources carrying capacity in Guangzhou city, China

The quantity and quality of water resources are of vital importance to the sustainable development of the social economy. Accordingly, research on the water resources carrying capacity (WRCC) has received wide attention from scholars. The WRCC system comprises multiple complex and nonlinear interactions related to society, economy, water resources and the water environment. A full understanding of its internal mechanism is conducive to the further improvement of the regional WRCC. In this study, the system dynamics (SD) model is applied to establish the dynamic feedback system of the WRCC. The quantitative and qualitative evaluation of WRCC is conducted by coupling the analytic hierarchy process (AHP), entropy weight method and multiobjective linear weighting function. Furthermore, the coupling coordination degree model is introduced to rate the coordination of the WRCC system. Five typical scenarios designed for distinct purposes are simulated by the constructed SD model in Guangzhou from 2021 to 2030. The results indicate that the rapid economic development scenario performs worst in terms of WRCC (0.39 in 2030) and coupling coordination degree (0.28 in 2030), the water environment protection scenario and water conservation scenario are considerably effective for improving WRCC and promoting its coordinated development, and the comprehensive scenario performs best in both aspects. Pearson correlation analysis shows that there is a strong positive correlation between WRCC and coupling coordination degree, with a correlation coefficient of 0.91. Thus, to further enhance WRCC, we must attach great importance to regional coordinated development. In view of the problems existing in Guangzhou, several feasible suggestions are put forward for improving water use efficiency, reducing pollutant emissions and developing high-tech industries. This research can provide a scientific reference for promoting regional sustainable development.