长江九江段40年来河道演变的DEM研究

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

利用地理信息系统(GIS)与数字高程模型(DEM)技术,模拟了40年来长江九江段的冲淤过程,结果表明:1963-1972年,总体表现为淤积,淤积量为650 5万m3,平均淤积速率为65万m3/a。1972-2002年,总体表现为冲刷,冲刷量为2072万m3,平均年冲刷率为103 6万m3/a。1963-2002年,九江河床总体表现为冲刷,冲刷量为1497 7万m3。2003年与1963年比较,河床淤积区域主要在长江九江上段的近南岸区域、中下段的中间区域;冲刷区域主要在长江九江上段的中间及近北岸区域、中下段两岸的近岸区域。长江九江河段40年的演变是河床的边界条件、上下游来水来沙及人类活动耦合的结果。中下段南岸的不断刷深和南偏对九江的防洪带来更大的压力。

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 14.977×10~6m^3; From 1963 to 1972, the general result is sedimentation, the total disposition quantity is 6.505×10~6m^3, the average rate of disposition is 0.65×10~6m^3/a; From 1972 to 2002, the general result is erosion, the total erosion volume is 20.720×10~6m^3, and the average rate of erosion is 1.036×10~6m^3/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 continual erosion of the south bank area along the middle and lower channel bring the more pressure to flood prevention.