Analysis of the Evolution of Xiaomiaohong Based on Remote Sensing Axis Line Method

With the rapid development of tidal flat reclamation and construction of port in the Marine East of Jiangsu project, Xiaomiaohong creek nearby Lvsi port located at radial sand ridges sea area was selected as a typical area for understanding its topographic and morphological evolution, which is conductive to the construction of port. By using the Remote Sensing Axis Line method (RSAL), the Axis lines of Xiaomiaohong creek were extracted based on one MSS image and six TM images in the period of 1979, 1987, 1989, 1993, 1995, 2003 and 2009. The results showed that: (1) on the basis of overlaying generated axis line and DEM (digital elevation model) data both acquired in 2003, axis line can be the substitution of the thalweg line because of similar trend and minor deviation of above two kinds of lines, which is revealed that RSAL was serviceable and effective to understand dynamic evolution of tidal creeks quickly and accurately; (2) deviation between axis line and thalweg line is inevitable because of the slopes of both side is asymmetric. The biased distance depended on the slope degree of creeks. The much larger slope degree is, the further distance is shifted; (3) from 1979 to 2009, the front end of Xiaomiaohong creek were growing and its subordinate branches were eroding. Some new subordinate branches were turned out and developed in southern part caused by the strong hydrodynamic condition. Based on the comparison, the entire tidal creek was relatively stable.