Monitoring and predicting the shoreline change in Can Gio area in condition of the sea level rise

Abstract

Locating on the domestic and international navigation routes (Long Tau-Tac Dinh Cau route, Soai Rap route) the Can Gio area is impacted by waterway traffic activities. The seasonal movement of sand bars on the Can Gio is significantly impacted by hydrodynamic of the river mouth. With the important roles of the area, the authors consider the coastal morphology processes under the hydrodynamic. In this paper, the authors has inherited previous studies combined the satellite image analysis to detect the shoreline changes from 1973 to 2013. Besides, numerical modeling was also applied to predict the shoreline changes under impacts of the sea level rise. Results show that, the Can Gio shoreline prolonging from Can Thanh to Dong Hoa is seriously eroded, with average of 7-10 m/year, maximum to 15 m/year. It is found that, beach erosion at Can Gio is a kind of surface erosion impacted by human trigger (shrimp ponds, beach encroachment…). In addition, natural factors (wave, long-shore current, littoral materials) also contribute to increase the erosion rate. Predicted results with sea level rise scenarios show that, the Dong Hoa and Can Thanh will be seriously eroded while the 30-4 beach will be annually deposited.