River mobility in response to hydrological fluctuations: insights from the meandering Powder River (Montana, USA)

River mobility reflects the capacity of fluvial systems to adjust their planform in response to variations in discharge and sediment. Understanding how rivers respond to hydrological fluctuations is particularly important in environments where flow regimes are highly variable and geomorphic adjustments can be rapid and episodic. This study investigates the relationship between river mobility and hydrological variability along the Powder River (Montana, USA), a dynamic, meandering system. River mobility was quantified using migration rate via R processing in QGIS and MATLAB over the study period. Channel centerlines extracted from satellite imagery were compared to measure channel migration and identify spatial and temporal patterns of planform adjustment. Hydrological variability was characterized using the daily discharge data movement. Results indicate that there’s no evident correlation between channel migration and daily discharge. High-flow events, particularly peak discharge periods, were found to play a dominant role in driving lateral channel adjustment, while low-flow conditions corresponded to reduced mobility. The findings suggest that river mobility in the Powder River is highly sensitive to hydrological fluctuations, with short-term flow variability exerting a measurable influence on long-term channel dynamics. This research highlights the importance of integrating hydrological records with geomorphic indicators such as migration factors to understand river mobility better. The study contributes to improved knowledge of relationships in meandering rivers and provides insights relevant to river management, hazard assessment, and the prediction of channel responses under changing hydrological regimes.