EFFECTS OF SEDIMENT SUPPLY ON COASTAL SALT MARSH EVOLUTION

摘要

During the past century, natural and human modification of environmental system has greatly accelerated coastal salt marsh deterioration and shore line retreat in many regions worldwide. More and more attentions begin to be paid to the coastal salt marsh as a decreasing transition zone between land and sea. In particular, many studies address to the evolution of coastal salt marshes since they are particularly vulnerable to the change of environmental system. Wave energy, tidal current strength, tidal range, sea level rise, inundation period, shelter condition, vegetation, coast stability, deposition rate, artificial impacts and so on are generally considered to be the important factors contributing to evolution of coastal salt marsh. Besides, sediment supply, especially fine sediments is one of the essential stuffs to control the development of coastal salt marsh. A methodology combining field investigation and sampling, grain size analysis, profile measurement, geographical information analysis and remote sensing was employed to study the effects of sediments on coastal salt marsh, using Jiangsu Mud Coast as a case study in this paper. The development of salt marsh is determined by the change of canopied area estimated from different satellite images. The sediment supply condition is inferred by sampling from both salt marshes and closer mud flats, and by rational discussion of the dynamic conditions of Jiangsu Mud Coast as well. The results indicate that the development of salt marshes is closely relevant to regional sediment conditions.