Dynamic evaluation of comprehensive water environment carrying capacity in the Three Gorges Reservoir Area using game theory combination weighting and system dynamics

Abstract Amid rapid global economic growth and increasing human activities, watershed systems are increasingly threatened by resource scarcity, water pollution, and ecological degradation. As a critical ecological barrier and strategic water resource zone within the Yangtze River Economic Belt, the Three Gorges Reservoir Area (TGRA) faces pronounced conflicts between water resource utilization and environmental protection. To address these challenges, this study established the Comprehensive Water Environment Carrying Capacity (CWECC) assessment system for the Three Gorges Reservoir Area (TGRA) by integrating the Driver-Pressure-State-Impact-Response-Management (DPSIRM) framework with system dynamics modeling. CWECC evolution under multiple scenarios from 2023 to 2035 was simulated. Results show an overall upward trend: the comprehensive development scenario performed best, reaching 0.6348 by 2035, while the rapid economic growth scenario improved least, reflecting pressures from high-pollution industries. Spatially, CWECC was highest at the reservoir head, the middle had the greatest improvement potential, and the tail offered opportunities through pollution control and water management. These findings demonstrate that strategies combining ecological protection, efficient water use, and high quality growth can enhance CWECC. The proposed dynamic, multi-scenario framework addresses limitations of static assessment and offers quantitative support for differentiated watershed management.