Multivariate Controls on Bed Turnover in Braided Rivers

Abstract Braided rivers with multiple threads exhibit variable, sometimes chaotic movements, making it difficult to characterize their mobility and identify the climate, tectonic, and land‐cover conditions that drive their behavior. Using 25 years of satellite imagery from 20 braided rivers, we measured “bed turnover”—successive conversions between land and water—within a channel belt that represent changes in channel‐thread configurations. Multivariate analysis comparing bed turnover to environmental factors (e.g., sediment supply, water discharge, and vegetation) shows that braided rivers group into three mobility styles associated with different combinations of conditions. Low Mobility systems are highly vegetated and have low sediment supplies. High Mobility systems are generally steep, have high bedload flux proportions and efficiently rework their channel networks. Variable Mobility systems commonly have seasonally variable water discharge and exhibit more channel‐margin/floodplain reworking than others. These results demonstrate the power of multivariate analysis for contextualizing and managing rivers.