Evaluation of Water Environment Carrying Capacity in the Shaanxi Section of the Wei River Based on a Comprehensive Index System

The Shaanxi section of the Weihe River Basin has undergone significant environmental changes in recent years, marked by pronounced spatiotemporal variations that pose substantial challenges for sustainable water resource management. Traditional evaluation methods often fall short in capturing the dynamic evolution and structural complexity of such systems. To address these limitations, this study adopts the Driving force-Pressure-State-Impact-Response-Management (DPSIRM) model, integrated with the coefficient of variation method, to comprehensively assess the Water Environmental Carrying Capacity (WECC) and its key influencing factors. Drawing on data from 41 districts and counties and employing Xi'an as a representative case study, the research reveals clear regional disparities and temporal trends in WECC. The results indicate an overall upward trend in carrying capacity, with upstream areas improving from Level III to Level I, middle reaches from Level IV to Level II, and downstream areas from Level V to Level III. The pressure and state subsystems were identified as having the most significant impact on WECC evolution. Meanwhile, indices associated with driving force, pressure, and management showed a rising trajectory, whereas state and response subsystems exhibited fluctuations. This study confirms the practicality and effectiveness of the DPSIRM framework in dynamically evaluating WECC, offering a robust scientific foundation for refined, region-specific water environment governance.