Abstract:

The evolution processes for Meiizhou reach in the Yangtze River were studied based on the digital elevation models (DEM) of the lower reach of the Yangtze River for the years of 1959，1970，1983，1992 and 2003.Three profiles were investigated.The shift velocities of the waterfront of the profiles，1#，2# and 3#，were respectively 500，1880 and 4364 m/a，in the stage before the construction of the revetment.But these decreased to 115，600 and 9.15 m/a thereafter.The shift velocities of the thalweg changed from 845，3118 and 5000 m/a to 550，535 and 475 m/a，the proportion of the width and depth，changed from 424，320 and 257 to 393，278 and 225.These results indicate that since the revetment has been finished，the shift range of left bank and thalweg has decreased distinctly and the channel planar distortion is controlled effectively.The shoal head of Meizizhou has become deeper and narrower.The river channel shows the tendency of stability.The Third Nanjing Yangtze River Bridge has good effect on controlling the evolution process of the Meizizhou reach in the Yangtze River.

Key words: GIS, the Yangtze River, Meizizhou reach, revetment, channel evolution