Analysis of Jiujiang reach of the Yangtze River evolution in recent forty years using the DEM

The Jiujiang reach evolution of the Yangtze River recent forty years is rationally simulated by the digital evevation model(DEM)and the GIS technology The research result are as follow:Jiujiang river channel is general charactered by erosion from 1963 to 2002,and the total erosion volume is 14.977×10⁶m³;From 1963 to 1972,the general result is sedimentation,the total disposition quantity is 6.505×10⁶m³,the average rate of disposition is 0.65×10⁶m³/a;From 1972 to 2002,the general result is erosion,the total erosion volume is 20.720×10⁶m³,and the average rate of erosion is 1.036×10⁶m³/a;And the main area of disposition locats in the south bank area including the middle channel and the middle area of the lower channel and the main area of erosion locats the channel north bank area and the south bank area of the lower channel The channel change is due to the result of the channel borderline conditions,the water flow,the suspended sediment load and the human activities The cont inual erosion of the south bank area along the middle and lower channel bring the more pressure to flood prevention.