Many large reservoirs have been built in large river basins around the world, which have met the needs of water resources, flood disaster regulation and power generation. With the increasing demand for green energy, more large reservoirs will be built. The reservoirs store water in flood season and release water in dry season, which has a seasonal regulation effect on river discharge in the lower reaches of the river. The flood disasters mainly occur in flood season, and estuarine saltwater intrusions mainly occur in dry season. The seasonal regulations of river discharge by reservoirs in the basin are bound to have an impact on the downstream freshwater resources and flood disasters. In addition, the reservoir dams intercept sediment, resulting in the reduction of sediment in downstream rivers and estuaries, which have had an impact on siltation and the environment. The international workshop will discuss the impact of basin reservoirs on downstream freshwater resources, flood disasters, erosion and deposition, as well as estuarine and offshore environment, so as to make better use of freshwater resources, reduce flood disasters and protect the ecological environment.