China's nationwide streamflow decline driven by landscape changes and human interventions.

China's rivers support nearly 20% of the global population and supply freshwater for the world's largest proportion of industrial output and grain production. Despite their importance, nationwide streamflow changes and their drivers remain unclear because of challenges in accessing observations and disentangling the effects of climate, landscape, and human interventions. By combining data from 1046 hydrological stations with ISIMIP3a reconstructions, we provide a comprehensive national assessment showing that streamflow has declined across more than 70% of stations over the past six decades. Although regional heterogeneity exists, these declines are primarily concentrated in the north and driven by land use and cover change, further exacerbated by water abstraction, diversion, and regulation. In contrast, climate change and variability dominate the increases in streamflow, primarily in the south. Our results provide insights for water managers, helping them understand the multifaceted drivers of hydrological variability and inform the development of infrastructure and ecological projects to mitigate potential risks associated with declining streamflow.