关键词: &ldquo, 一江两湖&rdquo, ； 泥沙分布格局； 多重人类活动； 泥沙补给； 长江中下游

Abstract: The huge and complicated river-lake system of Yangtze River is composed of the middle reach of Yangtze River, Dongting Lake and Poyang Lake that naturally connected to it. This system has the most abundant water resources and is one of the key areas of Yangtze Economic Zone. During the past 60 years, the internal and external environment changed remarkably due to highly intensified human activities, which has further altered the sources, amount and distribution pattern of sediment in the river-lake system. By employing the measured sediment data, the flux of sediment in different controlling areas were calculated and the results revealed the 3 phrases of sediment pattern adjustment: balance in the river and deposition in the lakes from 1956 to 1980, deposition in river and lakes from 1981 to 2002, sediment supplement by river and lakes from 2003 to 2015. The distribution pattern of sediment in river-lake system has been influenced by extreme flow regimes and multiple human activities such as the lower Jingjiang cutoff project, soil and water conservation projects, lakes reclamation and operation of large reservoirs.

Key words: middle Yangtze River and two connected lakes, distribution pattern of sediment, multiple human activities, sediment supplement, middle and lower Yangtze River