This review presents an overview of the advances of knowledge and research into the depositional and erosional mechanisms, as governed by the tide, waves, sea level and saltmarsh plants, involved in the formation of mudflat and saltmarshes during this century. Our understanding of physical processes on mudflat and saltmarshes has been stimulated by the results of dynamic behaviour cf marine finegrained sediments over the last several decades. Developments in the techniques available to the earth scientist have allowed detailed scrutiny of the processes affecting coastal saltmarshes at scales not previous considered. The application of knowledge of saltmarshes processes in coastal defence and other schemes has been increasingly attempted in recent years.