On the Response of Shallow-water Tidal Regime by Geological Characteristic of Waterway and Man-made Structures in a Macrotidal Estuary: Han River Estuary (Korea)

초록

To understanding shallow-water (short- and long-term period than semidiumal tide) tidal regime in a macrotidal estuary, Han River estuary (HRE), located on the west coast of South Korea, tidal harmonic constituents of 20 stations were analysed. The semidiumal tide dominated HRE consists of two main waterways, which have complex geological characteristics. The shallow and narrow characteristics of waterway transform propagating astronomical tides from the open-sea to shallow tidal components such as overtides and compound tides. The shallow tide (e.g., M-4, MS4, and MSf.) is important factors, which is determined water and mass circulation in a macrotidal estuary. To find shallow-water tidal regime characteristic in this study, we suggest short- and long-term period of tidal form number using shallow tidal constituents. The short-term period of tidal form number covers a range from 0.02 to 0.43, and it increase 10 times larger in the upstream estuary than the open-sea. The long-period of tidal form number is small in the open-sea, but going upward to the estuary, the value increases by 10 times, and it shows 100 times greater than that of the open-sea at the upper region of Han River. Due to complex geological characteristics of waterway, the amplitude of astronomical tidal constituent rapidly decrease and shallow water tidal constituent sharply increase. The other rapid change of tidal constituent is caused by the influence of man-made structures (Singok underwater dam) in the lower tidal river. It is apparent that regional characteristic of tidal regime caused by geological effect and influence of man-made structure.

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