Data and code for: River planforms originate from (im)balance between riverbank erosion and bar accretion

Why rivers confine flow to a single channel (single-thread planform) or divide flow into multiple sub-channels (multi-thread planform) forms a longstanding fundamental question in river science, which to date remains poorly understood. In the associated manuscript, we probe planform origins using a novel dataset of 11+ million riverbank migration vectors mapped from 36 years of global satellite imagery along 84 river systems. Results show single-thread rivers originate from a balance between bank erosion and opposing-bar deposition, which maintains an equilibrium width as channels migrate. In contrast, multi-thread rivers originate from imbalance: bank erosion outpaces opposing-bar deposition, causing sub-channels to repeatedly widen and split. This width instability challenges equilibrium paradigms in river science, endangers riverside communities, and lowers the potential costs of nature-based river restoration projects along multi-thread rivers. Here, we provide the data and codes that form the foundation of this manuscript.