ANALYSIS OF EROSION AND DEPOSITION IN THE YANGTZE ESTUARY SUBAQUEOUS DELTA

摘要

The sediment of the Yangtze estuary primarily comes from the Yangtze drainage area.After the operation of Three Gorges reservoir, the sediment discharge of the Yangtze drainage has greatly decreases, leading to the change in the Yangtze estuary. It has tremendous influence on the estuary stability. The analytical result which bases on more than 40 years the field data indicates that, when the annual runoff is 26452m3/s and the annual sediment discharge is 3.66×108 tons at Datong station, the isobaths in the Yangtze Estuary subaqueous delta remain unchangeable. The paper will separately adopt the material analysis and one dimensional mathematical model , which are used to forecast the runoff and sediment discharge at Datong station after the Three Gorges reservoir running 20 years, the results indicate , the annual runoff is invariable basically,but the annual sediment discharge at Datong station is about 2.17×108 tons, reduces by 48.5% compared with before the operation of Three Gorges reservoir, so the Yangtze Estuary subaqueous delta will be eroded.