资源环境科技发展态势分析平台

Individual grains move through gravel bed rivers in cycles of motion and rest, so tracer grains diffuse as they transport downstream. Tracer experiments demonstrate at least three diffusion ranges as observation times increase, with different spreading rates in each range. Up till now, the generating processes of these ranges remains unclear. In this work, we develop a random walk model of individual bedload trajectories including motion, rest, and burial processes. The model describes three bedload diffusion ranges that terminate in a fourth non‐diffusive range when all tracers become buried. Using the model, we attribute three‐range tracer diffusion to the interplay between motion, rest, and burial processes, and we relate the multi‐range diffusion characteristics to the timescales of these processes.