长江大通站水沙过程的基本特征 Ⅱ. 输沙过程分析

长江入海泥沙丰富，对长江三角洲的发育、河口滩槽冲淤演变及开发治理有重要影响.大通站1953~2000年输沙序列的趋势分析和周期分析表明，虽然宜昌站输沙量和大通站径流序列无显著趋势变化，但是大通站的年输沙序列(尤其是汛期各月输沙序列)却呈现较显著的下降趋势，这主要与洞庭湖、鄱阳湖及江汉湖群淤积等因素有关.由于流域产沙区主要集中于上游地区，上、中、下游的产沙效应有很大差异，因此，水沙情势相吻合的年份仅有三成.月输沙更加集中于汛期，5~10月的输沙量占全年的87.7%.关于洪枯季的输沙匹配状况也作了初步分析.

The Basic Character on Process of Runoff and Sediment Discharge at Datong Station of the Changjiang River Ⅱ.Analysis on sediment transport process

The Changjiang river is rich in sediment supply which exerts an important influence on development of the Changjiang delta, evolution of shoals and channels in the estuary, realignment and utilization of the estuary. Trend analysis and period analysis on the sediment transport series at Datong Station state that an obvious decrease trend has emerged in the annual series of sediment transport at Datong Station although the sediment discharge at Yichang Station and the annual runoff series at Datong Station have little change trend. The situation is mainly related to shoaling of Dongting Lake, Poyang Lake and other lakes. The sediment-producing region is mostly located in the upper reach and sediment-producing effect of upper, middle and lower reaches is obviously different, so that sediment transporting situation is responded with runoff discharge only about 30% of years in the series. As for monthly distribution of sediment discharge, some 87.7% of suspension loadsare discharged through the Datong section from May to Octorber. In addition, the matching status of sediment discharge between flood and dry seasons is preliminarily analyzed in the paper.