Abstract:The flow-sediment regime entering the lower Yellow River (LYR) has changed significantly since 1986.In order to study this phenomenon,the reach-scale bankfull channel dimensions (bankfull width, depth, area, et al.)of the braided reach were calculated annually during the period from 1986 to 2012,based on the surveyed post-flood profiles at 28 sedimentation sections,using an integrated method which integrates a geometric mean based on the log-transformation with a weighted average based on the spacing between two consecutive sections.The results indicated that the magnitude of each reach-scale bankfull channel dimension responded well to the accumulative effect of incoming flow and sediment conditions during both the flood seasons and non-flood seasons.Empirical relationships for the braided reach were developed between the reach-scale bankfull channel geometry and the previous four-year average integrated incoming discharge-sediment condition.These relationships demonstrated different impacts of discharge and incoming sediment coefficient on the channel geometry with relatively high correlation coefficients between them.