Morphological impacts of tidal residual currents in the Taiwan Strait

There are many spectacular manifestations of morphology that appear in the Taiwan Strait (TWS) of China. Comparing these morphological manifestations with the patterns of tidal currents computed on seas surrounding Taiwan (Juang et al 2001), the tidal residual currents were suspected to be the dominant mechanisms of generating the most important impacts on morphology in the strait. By implementing a sediment transport model: MIKE21_ST (DHI 1996), the distribution of capacities of sediment transport that induced implicitly by tidal currents with duration covering from neap to spring tides is computed and applied to investigating the morphological impacts. From the computational distribution of sediment transport capacities, one can find that the predominant direction of sediment transport appeared evidently as northward going in TWS. Regions with high transport capacity, where significant erosion will appear, are located at three zones: ( I) the most southern water around Hengchun peninsular, (2) the south water, and (3) the north water of the strait. Zones with low transport capacity, where deposition can be expected, are confined only to the central water of the strait. Furthermore, the erosion/deposition trends that evaluated and demonstrated by the sediment transport capacities exhibit satisfactory agreements with the physical appearances of morphology. The morphology impacts dominated by tidal residual currents, therefore, are identified.