Channel planforms and morphodynamic diversity of the upper Himalayan upland rivers

River patterns and planform changes play a pivotal role in shaping planetary surfaces and driving sediment reworking. In the upper high Himalayas, some of the Earth’s highest floodplains have been sculpted by rivers, forming remarkable upland braided and meandering belts in the high Himalayas. While lowland fluvial dynamics are well-studied, the morphodynamics of upland river systems remain poorly understood. This study systematically analyzed river patterns and channel morphodynamics in Himalayan upland alluvial rivers through a combination of remote sensing and comprehensive field investigations. Our results reveal a diverse array of planform behaviors, including meandering, anabranching, braiding, cutoffs, avulsions, and transitions, within these high-altitude systems. Over the past 40 years, meander migration rates have increased by ~78%, accompanied by more frequent cutoffs, avulsions, and pattern transitions—phenomena closely linked to upland climate change. These findings underscore the unique channel morphodynamics and intense lateral movements of sparsely vegetated upland rivers, advancing our understanding of upland river evolution in a warming climate. Additionally, these insights may inform the reconstruction of paleochannels on barren landscapes such as early Earth and Mars.