Author(s): Ling Jiang; Yitian Li; Wei Zhang
Linked Author(s): Wei Zhang
Keywords: Multi-branched river; Hydraulic factor; The Three Georges Project; Evolution trend
Abstract: The development and decline of branches are closely related to the movement of water and sediment, and influenced by river channel form. Under long-time function of incoming water & sediment condition, as well as human impact, river channel has different channel form and behaves different evolution characteristics. The Shashi Reach in Yangtze River is straight and slightly curing, where side bars and central bars are distributed alternately. With changes of incoming water & sediment condition, riverbed relief has evolved continually. In this paper, various changes in the channel are studied basing on available topographic maps and survey data of hydrology and sediment. It is found that: (1) channel form is the important factor controlling shoals evolution, and incoming water & sediment condition only plays a role accelerating or decelerating the evolution, (2) under the condition that the channel plane form is stable, hydraulic process of water flow and sediment is the dominant factor determining the rise or decline of the branches. The Shashi Reach is the first sandy reach downstream from the Three Georges Dam (TGD), and will suffer erosion firstly after the dam impoundment. Basing on the water and sediment transport characteristics, possible responses of channel evolution to the dam impoundment are discussed. These conclusions have significant implications for river training and research on evolution law of multi-branched river.
Year: 2007