Impacts of Human Activities on the Sediment Regime of the Yantze River

The Yangtze River (Changjiang) is one of the most important rivers in the world, and the alterations in its hydrological regime have global-scale impacts. However, with population increase and economic growth, the sediment regime of the Yangtze River has been altered to some extent by human activities, including dam construction, deforestation, soil and water conservation, etc. The alteration in the sediment regime of the Yangtze River will unavoidably influence its morphology and geomorphology, the delta evolution and the ecosystem health and stability. To assess dam-induced alterations in the sediment regime of the Yangtze River quantitatively, the Danjiangkou Reservoir, the Gezhouba Reservoir and the Three Gorges Reservoir have been selected as case study sites, and the whole study period was divided into four sub-periods according to the years when these three reservoirs started to store water. On the basis of the time series of daily sediment discharge from six key hydrological stations (Wanxian, Yichang, Hankou, Datong, Baihe and Xiantao), the changes in annual, seasonal and monthly sediment load in different sub-periods, and the driving forces, were explored. The results in this paper could provide a reference for the assessment of impacts of human activities on the health and stability of the Yangtze River ecosystem.