Sediment transport processes over a sand bank in macrotidal Garolim Bay, west coast of Korea

Abstract

A sand bank at the mouth of macrotidal Garolim Bay, west coast of Korea is investigated by means of morphological surveys and current measurements for unraveling sediment transport processes relevant to its formation and maintenance. Bedload transport rates calculated from current data show that mutually evasive tidal currents flowing obliquely to the bank through surrounding channels play a principal role on sediment transport over the sand bank. Flood-oriented bedload transport is dominant on the eastern flank of the bank, whereas ebb-oriented transport dominates the western flank, resulting in bedload convergence towards the crest. Surface bedforms, mostly large dunes, suggest a clockwise sand transport around the sand bank, generally coincident with the pattern revealed by bedload calculations. Although the tidal currents are principal processes responsible for the sand-bank dynamics, the predominance of flood-oriented dunes at the bay mouth is indicative of a significant role of winter waves enhancing flood-oriented transport at the mouth. The sand bank appears to be in a dynamic equilibrium, since it has remained stationary for last 25 years.