关键词: 河道演变, DEM, 可视化表达, 长江

Abstract: The purpose of this paper is to analyze the evolution characteristics of the river channel of south branch in the Changjiang River estuary for the recent 100 years visually and quantitatively with the help of DEM technology. In support of GIS, 5 pieces of charts of south branch from 1900 to 2001 are digitized and the digital elevation model(DEM) of south branch in different periods is established with Kringing gridding method. On the basis of the above approach, the evolution of the river channel of south branch is visualized and the characteristics of erosiondeposition sedimentation are analyzed. The results show as follows: (1) DEM is an effective means for visualization and quantitative analyses of environmental evolution. (2) The river channel storage volume below 0 m increased slightly with the annual average rate of 0.027×108 m3，which coincided with the state of slight erosion of entire river channel with the annual average rate of 0.033×108 m3 of volume and 0.37 cm of thickness respectively from 1900 to 2001. (3) The states of erosion and siltation were different in different time domains and different stretches, scouring before 1958 and after 1979, whereas filling from 1958 to 1979; changes of cross sections at the entrance and exit were more intense than those in the middle of south branch.