Abstract
The amplitude of tides in the Ariake Sea and surrounding area has been decreasing since mid-1980s. However, the amplification of M2 constituent at the Oura Tide Gage Station to the Kuchinotsu Tide Gage Station increased betweenearly-1970s and mid-1980s and then decreased. The Isahaya Reclamation Project and changes in sea surface elevation were considered to be the factors contributing to this change. Much effort has been spent on quantify the effects using numerical models. However, the increase in tidal ranges between early 1970s and mid-1980s could not be consistently correlated with these factors: the results varied between analyses depending on the numerical model used. On the other hand, the patterns of change in the tidal current could not be clarified because of an absence of reliable field data. Therefore, numerical model simulations and hydraulic model experiments have been conducted to quantify the effect of the following factors: the Isahaya Reclamation Project, seaweed cultivation and the new Kumamoto Port. Yet from these efforts, the extent and degree of the influence of these factors have not been clarified. Development of a fine mesh model, which can simulate the tidal change and a 3D-current with high accuracy based on highly accurate tidal current survey, is therefore recommended.
