Migration of River Mouth Opening in Opak River, Yogyakarta, Indonesia

抄録

 Opak river mouth, located in Yogyakarta, Indonesia, has dynamic morphological features with active migration of the river-mouth opening. Several studies have been done around the location. However, processes of the river-mouth opening migration have not been fully understood. This research is aimed at elucidating the processes of the river-mouth migration. A series of aerial images of the study area were firstly analyzed to clarify the general tendency of short-term and long-term migration of the river mouth. A number of simulations were then conducted using an online-coupled model of Delft3D Flow and Deflt3D Wave (SWAN). The short-term behaviors of the migration was partially reproduced by the model, although the long-term migration was not well captured. The model results suggest that asymmetric features of tidal currents through the opening over ebb-flood and neap-spring cycles play a key role in the morphological evolution.