Factors affecting the formation of a new island in front of Cua-Dai river mouth, Thu-Bon river

Abstract

     The area of Cua-Dai estuary and the coastal areas of Hoi-An City have experienced complicated erosion and sedimentation in recent years. Along the coast of Hoi-An, erosion often occurs, whereas in the area of Cua-Dai River, there is an accretion phenomenon that obstructs the waterway navigation from Cua-Dai to Cu-Lao-Cham. The occurrence of sand dunes in the offshore location of Cua-Dai has been recorded a number of times in recent years. The purpose of the study is to find out one of the potential causes that may be related to the formation of a new island in the estuary. Research results show that the amount of sediment from upstream of the Thu-Bon river has a great influence on the change of bathymetry of the estuary. The research results also show the trend of coastal sediment movement in the south direction during the simulation period from January 2016 to May 2019 in the study area. This study used the numerical model Telemac which combines the hydro-morphodynamic and wave modules