A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Advanced Technoologies

Thesis (M.Sc.) - Asian Institute of Technology, 2003

Coastal zone is a very complex, dynamic and delicate environment, because this area is a transition, mixture between land and marine process. A relatively quick change has been observed in this area. For example, from the processes those occur in the coastline, abrasion occurs in some places and sedimentation occurs in another part, or even occurs in the same area but in different time periodically. Coastal zone is an environmentally sensitive interfaces between the ocean and land and respond to changes brought about by economic development and changing land-use patterns. This study mainly focuses on applying satellite digital images processing techniques for monitoring coastline changes at two inlets of Tam Giang - Cau Hai Lagoon area. Especially, the study has developed a methodology to extract shoreline information based on mathematical morphology technique. A GIS approach was used for integrating digital images data of quantitative analysis and making the thematic maps. The regression model was applied for prediction of coastline changes in the future. The result of the study shows that the erosion and accretion have taken place complicatedly at the Thuan An and Tu Hien Inlet area. From 1989 to 2002, at the Thuan An Inlet area was accreted about 21.0 ha and eroded about 52.6 ha. From 1989 to 2001, Tu Hien Inlet area was accreted about 21.4 ha and eroded about 52.8 ha. It was predicted that the Thuan An Inlet had a tendency to move up North when it was accreted at the Thuan An Village coastline and eroded at Hai Duong Commune coastline, and the erosion will be taken place strongly at Hoa Duan Inlet. Tu Hien inlet has the tendency to enclose when the two sides coastline of inlet have been accreted with the high rate. It has been found that high spatial resolution satellite data is very effective for monitoring coastline changes. Also GIS has been found to be useful in analyzing shoreline changes quantitatively by overlaying multi temporal shoreline maps. The research also shows that mathematical morphology approach can be used to extract linear features such as shoreline from satellite images effectively.