Discussion on channel shrinkage and its instability of the Lower Yellow River

The authors discussed the hydrological and sediment conditions for the formation of channel shrinkage in the Lower Yellow River, which happened during the period from the mid 1980s to the late 1990s. This new problem of fluvial processes was characterized with continued siltation in channel bed, continued decrease of cross-sectional area of channel and continued diminution of flow conveying capacity. Deposition has continuously happened in the main channel by moderate and low incoming runoff with hyper sediment concentration in a series of dry years and resulted in channel shrinkage. The deposition also occurs in low floodplains so that the main channel is narrowed and the channel shrinks strongly. The configuration and cross-section of the withered channel are instable and would possibly be modified under favorable conditions of incoming runoff and sediment load. Therefore, the resuscitation of the shrunk channel could be anticipated. Some measures are suggested to accelerate the resuscitation. Especially, regulation of flow and sediment in the Xiaoliangdi Reservoir would play a significant role.