【摘要】 本报告是根据长江五十年的水沙资料 ,宏观分析长江干支流各主要水文站水沙发展趋势 ,发现干流汉口站、大通站、宜昌站平均年输沙量都有明显减小趋势。各主要支流水文站减沙趋势明显 ,汉江皇庄站平均年输沙量减少得最为显著。但金沙江的屏山站近期平均年沙量有增加的趋势。长江向洞庭湖分洪分沙的减少 ,使长江干流增沙。根据各站水沙资料分析了长江干流各河段发生的冲淤。文章还分析了大通站的水位流量关系和流量输沙率的关系 ,发现近年来大通站同流量水位有所下降和同流量输沙率也有减小的趋势。更多还原

【Abstract】 The variation trend of runoff and sediment load in Yangtze River was analyzed,based on 50 years hydrological data.It is found that,the yearly-averaged sediment load is obviously decreasing at Hankou,Datong and Yichang hydrological station,and the yearly-averaged sediment load is also decreasing at all tributaries in Yangtze River.Among them,the largest amount of reduction can be found at Huangzhuang on Hanjiang River,which is one of the biggest tribtutaries of Yangtze River.On the other hand,yearly-averaged sediment load is increasing in Jinshajiang,the upstream of Yangtze River.The reduction of flood and sediment diverted to Dongting Lake from Yangtze River result in the increase of sediment in the lower reaches of the River.According to the analysis the probable deposition and scour in the river reaches downstream of Yichang are forecasted which is important to the operation of the Three Gorges Project.更多还原