Spatial distribution and sustaining conditions of meandering and braided river clusters on the Qinghai-Tibet Plateau

This study aims to completely reveal the overall characteristics and formation mechanisms of fluvial landscapes on the Qinghai-Tibet Plateau (QTP). Based on field investigations (2010—2025) and GIS-based spatial analysis, we propose the concept of "alluvial river clusters" to describe the concentrated development of tributary and mainstem systems sharing similar channel patterns on the QTP . The results indicate that meandering and braided river clusters dominate the alluvial river systems: meandering clusters are predominantly found in the source regions of the Yellow River and Nu River, while braided clusters are extensively developed across the source areas of the five major rivers. The spatial distribution of these river clusters is jointly controlled by underlying surface characteristics and water-sediment conditions. Meandering clusters typically occur in basins with dense vegetation, gentle slopes, and higher water but lower sediment supply, whereas braided clusters form in areas with steeper valley gradients, sparse vegetation, and lower water but higher sediment supply. Furthermore, a significant positive correlation between valley slope and channel sinuosity was identified, revealing an intrinsic self-adjustment mechanism through which river clusters optimize energy dissipation. This study contributes a novel framework for understanding the structure, evolution, and climatic responses of alpine river network systems on the QTP.