Water scarcity and environment deterioration have become main constraints to sustainable economic and social development. Scientifically assessing Water Resources Carrying Capacity (WRCC) is essential for the optimal allocation of regional water resources. The hilly area at the northern foot of Yanshan Mountains is a key water conservation zone and an important water source for Beijing, Tianjin and Hebei. Grasping the current status and temporal trends of water quality and WRCC in representative small watersheds within this region is crucial for supporting rational water resources allocation and environment protection efforts. This study focuses on Pingquan City, a typical watershed in northern Hebei Province. Firstly, evaluation index systems for surface water quality, groundwater quality and WRCC were established based on the Pressure-State-Response (PSR) framework. Then, comprehensive evaluations of water quality and WRCC at the sub-watershed scale were conducted using the Varying Fuzzy Pattern Recognition (VFPR) model. Finally, the rationality of the evaluation results was verified, and future scenarios were projected. Results showed that: (1) The average comprehensive evaluation scores for surface water and groundwater quality in the sub-watersheds were 1.44 and 1.46, respectively, indicating that both met the national Class II water quality standard and reflected a high-quality water environment. (2) From 2010 to 2020, the region's WRCC steadily improved, with scores rising from 2.99 to 2.83 and an average of 2.90, suggesting effective water resources management in Pingquan City. (3) According to scenario-based prediction, WRCC may slightly decline between 2025 and 2030, reaching 2.92 and 2.94, respectively, relative to 2020 levels. Therefore, future efforts should focus on strengthening scientific management and promoting the efficient use of water resources. Proactive measures are necessary to mitigate emerging contradiction and ensure the long-term stability and sustainability of the water resources system in the region. The evaluation system and spatiotemporal evolution patterns proposed in this study can provide a scientific basis for refined water resource management and ecological conservation in similar hilly areas.

Pingquan City, the origin of five rivers, serves as the core water conservation zone for the Beijing-Tianjin-Hebei region and exemplifies the characteristics of small watersheds in hilly areas. In recent years, excessive mining and intensified human activities have severely disrupted the local ecosystem, creating an urgent need for ecological vulnerability assessment to enhance water conservation functions. This study employed the sensitivity-resilience-pressure model, integrating various data sources, including regional background, hydro-meteorological data, field investigations, remote sensing analysis, and socio-economic data. The weights of the model indices were determined using an entropy weighting model that combines principal component analysis and the analytic hierarchy process. Using the ArcGIS platform, the spatial distribution and driving forces of ecological vulnerability in 2020 were analyzed, providing valuable insights for regional ecological restoration. The results indicated that the overall Ecological Vulnerability Index (EVI) was 0.389, signifying moderate ecological vulnerability, with significant variation between watersheds. The Daling River Basin had a high EVI, with ecological vulnerability primarily in levels IV and V, indicating high ecological pressure, whereas the Laoniu River Basin had a low EVI, reflecting minimal ecological pressure. Soil type was identified as the primary driving factor, followed by elevation, temperature, and soil erosion as secondary factors. It is recommended to focus on key regions and critical factors while conducting comprehensive monitoring and assessment to ensure the long-term success of ecological management efforts.