The Growth And Evolution Of Tidal Creeks On The Prograding Mud Flat In Jiangsu Province

This thesis studies the tidal creek system on the prograding mud flat in Jiangsu province based on 16 pieces of MSS, TM and SPOT images from 1973 to 2001, and analyses the growth, genetic classification, evolution and affecting factors of tidal creeks. Tidal creeks on the prograding mud flat can be divided into three parts in plane form. There are five genetic classifications of tidal creeks as follows: tidal creek scoured by the currents of ebb tide; tidal creek eroded by stream from land; tidal creek scoured by conflux of rainwater; new tidal creek formed when the old moving; tidal creek scoured by the flood. Tide is the primary dynamic factor in building tidal flat; it must be affect tidal creek system on mud flat. Therefore, based on the raster image of the year of 2000, the thesis has built correlation equations between average tidal ranges and the density of tidal creeks, the ratio of the width of outlet to the length of low tidal shore, the ratio of the area of tidal creek to tidal basin respectively. The result shows that the former is high well-marked correlation; the two latter are well-marked correlation. The sediment of tidal flat affect tidal creek greatly too, especially affect the development of curve current of tidal creek. On the upper tidal flat, the clay is abundance, and the sediment is much more viscous, so the curve current develops well. There are four characteristics of the evolution of tidal creek as follows: (1) In the initial stages, tidal creek develops by continuous eroding trace to the source and depriving of the top of other tidal creeks. (2) The transverse moving of tidal creek occur mostly inthe lower part, the middle part and the outlet take second place, and the upper part is more stability. (3) The different level branches of tidal creek transform into each other in the whole evolution course. Finally, the thesis divide the evolution course of tidal creek into four phases: tidal creek of low mud flat - infancy tidal creek; tidal creek of upper mud flat - youth tidal creek; tidal creek of salt marsh - midlife tidal creek; abandoned tidal creek - dying tidal creek.