Tidal regime change due to the large scale of reclamation in the west coast of the Korean Peninsula in the Yellow and East China Seas

A depth-averaged two-dimensional numerical model has been established in order to investigate tidal regime change by the large scale of reclamation in the west coast of Korean Peninsula. The fetched variable-grid system was used to discretize the complicated coastal region efficiently. Maximum six month integration of the model was carried to investigate the tidal change over 10 tidal components prescribed along the open boundaries consisting of the Ryuku Islands, Korea Strait, and Tiwan Strait. The tidal regime change appears widely in the whole Yellow Sea and its effect reaches to the shelf break region in the East China Sea. The Kelvin-wave type distribution of tidal amplitude along the west coast of KP is distorted and the propagation speeds of semi-diurnal and diurnal tidal waves increase around the reclamation and neighboring regions. The change of the propagation speed after reclamation seems to be due to weaker lateral friction by simplification of the land boundary. The tidal amplitudes decrease within several tens of km just around the reclamation area, while the amplitudes outside the region increase slightly. Such decreasing or increasing patterns appear alternatively. This implies that the change of tidal regime propagates toward the remote region far away from the reclamation site. Therefore, prescription of tidal components as open boundary condition should be carefully determined after considering any possible tidal regime change near the boundaries by reclamation of an inner model domain. The model result also confirms that friction at the lateral boundary affects the propagation of tidal waves as much as the bottom-friction effect.