Experimental study on the formation and evolution of a braided channel with ‘lotus roots’

This study investigated the formation and evolution of a braided channel with ‘lotus roots’ through a series of experiments. The experimental channel was originally straight with unit cross-sections and was then successfully shaped into a braided channel with alternating wide and narrow reaches. Similarity law was applied to the design of the model discharge relating to its prototypical counterpart observed at the Huayuankou hydrological station in the lower Yellow River. The results indicated the following: ① the formation of the braided channel with ‘lotus roots’ was dominated by the aggregation process, which seems to be related to the growth of alternative bars in the straight channel; ② the geomorphological features of ‘lotus roots’ were highly related to the channel stability; ③ compound channel patterns were found to vary with discharge, i. e., braided with moderate flow and meandering with low flow, while the high flow tended to destroy both alternative bars and the pattern of ‘lotus roots’. This study represents a useful reference for flood control in the lower Yellow River.