The Hequ-Machang reach of the upper Yellow River in the Gannan Tibetan Autonomous Prefecture

a typical plateau braided reach

is characterized by a wide-shallow channel and its significant bed deformation and frequent bank erosion

threatening the safety of local infrastructure. Based on flow and sediment data

remote sensing images

and other multi-source datasets

new calculation methods are developed to quantify the channel width swept by mainstream migrating and the degree of channel planform braiding. We examine the process of river regime adjustment that occurred in the years of 2006-2021

focusing on a discussion on the impacts of flow-sediment regime. Results show the main channel in this reach manifested an equal shifting frequency in both left and right directions

with the average annual migration width of 60.6 m/a. However

at certain typical cross-sections

the width exceeded 100 m/a with the mainstream scouring the locations of the proposed bank revetment projects

which needs a special attention. The reach featured a moderate braiding intensity (an average braiding index = 1.9)

but significant longitudinal variations occurred with stronger braiding intensity in the upper and lower sections. Hydrodynamic conditions and sediment concentration are two major factors that affect the main channel migration and braiding intensity

respectively; their variations are reflected using certain combined flow-sediment indexes (e.g.

fluvial erosion intensity and incoming sediment coefficient). These indexes should also be suitable for revealing overall river regime adjustments in plateau braided reaches.