According to the design of the Three Gorges Project, the Three Gorges Reservoir will provide a buffering period approximately 50–80 years for sediment, during which much of the silt will be trapped in the reservoir and scouring downstream may remarkably increase. This declining trend in sediment transport was further exacerbated by the extreme drought in 2006, when the flood season water level was the lowest in the last 50 years (Dai et al. 2008); the water discharge decreased by ~30 %, and the sediment drastically decreased to 9 Mt (only 2 % of its 1950–1960s level). According to numerical modelling, the sediment load may reach a new balance in 2060–2110 (Yang et al. 2006).