Sediment transport from the Yangtze River, China, into the sea over the Post-Three Gorge Dam Period: A discussion

Sediment loads from the Yangtze River into the sea experienced a major increase in the late Holocene when sand beaches along the deltaic coast changed into tidal-flats. Sediment transport averaged about 472 million tons a year between the 1950s and the mid-1980s and decreased by 124 million tons a year after the mid-1980s, followed by a dramatic drop since the closure of the Three Gorge Dam (TGD). This paper discusses the major processes for the decline of sediment discharge since the 1950s and discusses the method for evaluating its future development over the Post-TGD Period. Sediment loads in the Post-TGD Period will be mainly determined by the major processes that may significantly contribute to the following three components, i.e. (1) the sediment input from the upper basin into the Three-Gorge Reservoir (TGR); (2) the ratio of sediment export from the TGR relative to the input and (3) the amount of sediment recovery downstream the TGD restrained by available sediment sources. An integrated evaluation shows that the annual sediment loads over the Post-TGD Period will possibly vary from 1.12 to 1.32 million tons a year or less in ordinary years.