Evolution, Recover And Rebuilding Of The Salt Marshes Along The Unerosional Coast In Jiangsu, China

In the paper, ten satellite photographs from 1979 to 2001 are studied to contrast and analyze the distribution area of the coastal salt marshes in different period using the software of Mapinfo 5.0. It discusses the influence factors and basic laws of the coastal salt marshes along the unerosinal coast in Jiangsu. At the same time, it also discusses the recover and rebuilding processes of the coastal salt marshes after the tidal flat was reclaimed.The conclusions are as following: (1) The natural prograding rate of thecoastal salt marshes is related closely to the annual prograding rate of the tidal flat.The natural prograding rate is P=1-, in which A means one salt marshesarea in one year and B means the salt marshes area after n years. The prograding rate is rapid if the prograding rate of the tidal flat is fast. In some coast, the revolution of salt marshes are influenced by the moving of the tidal creeks, especially that parallel to the salt marsh edge would move landward, which will make the salt marshes eroded. So the tidal creeks must be managed in order to recover the salt marshes. (2) In order to achieve the tidal flat sustainable utilizing, the ecology protection of the salt marshes must be considered when reclaiming. The reclaiming scale should be fit to the recovering rates of the salt marshes. The analysis indicates that the recovering rate of the salt marshes is related to theresidual salt marshes area outside the seawall. A formula of N = can beused to calculate the residual salt marsh area outside the seawall when reclaiming, in which M means the new reclaiming area of the salt marsh, P means the prograding rate of the salt marsh, n means the ecology recovering period which is equal to the interval between two reclaiming along the same coast. (3) Large enough area must be keep outside the seawall in order that the salt marshes recover naturally. If being kept actual reclaiming scale and rate, the salt marshes cannot recover inlO years. The natural recover period of salt marshes is 30years. (4) Recover salt marshes using manmade ecology engineer needs 10 years. TheSpartina Alterniflora is the extra category that is fit to the tidal flat in Jiangsu. The prograding rate of the Spartina Alterniflora vertical to the coast is slower and the prograding rate parallel to the coast is quicker through it also will be slower when expanding across the tidal creeks. Its expanding progress takes on parabola shape which has three stages: slow, quick, and slow. The ecology position of the Spartina Alterniflora connects with the ecology position of the natural salt marshes.In the end, this paper discusses the ingress influence of the manmade Spartina Alterniflora salt marsh to the coast in Jiangsu, China.