Hydrological alterations driven by climate change and human activities: historical attribution, future projections, and process mechanisms in the Daqing River Basin, China

ABSTRACT Human activities have significantly altered hydrological processes through land cover changes, water consumption, and engineering interventions. This study applies the Distributed Hydrology Soil Vegetation Model (DHSVM) to two mountainous catchments in the Daqing River Basin of North China to analyze historical and future hydrological changes. Using linear regression, Mann–Kendall tests, and moving t-test, we identify a significant decline in annual runoff since the 1980s, primarily driven by human activities such as land reclamation, groundwater extraction, and hydraulic projects. Attribution analysis indicates that human activities accounted for over 75% of the runoff reduction, while climate variability contributed 15–25%. Future projections based on 11 CMIP6 models and Bayesian model averaging show continued increases in precipitation and temperature throughout the 21st century, especially under higher emissions. Although increased precipitation can enhance surface runoff, recovery remains limited compared with historical losses. Moreover, climate change can lead to more uneven intra-annual runoff distribution, with reduced flows in early summer. These findings highlight the persistent influence of anthropogenic and climatic drivers on water resources and the ongoing challenge of recovery in heavily disturbed basins.