인공구조물에 의한 대항리 갯벌의 장기 지형변화

Abstract

The Daehang-ri intertidal flat located the just outside of the Saemangeum dike has been reported to show new-developing flats. Based on thetopographic surveys of 21 times from 2000 to 2016 by a leveling method every year, this site clearly shows variation of deposition/erosion in timeand space. Deposition has consistently occurred at the rate of +3.75 cm per year at the area along the dike (Zone 1), and this tidal flat is expandingand prograding seaward. In the area of far from the dike (Zone 2), on the other hand, erosion prevails at the rate of -2.38 cm per year, and thiszone tends to retreat landward. However, the erosional trend of Zone 2 has slightly slowed down since 2014. As a whole from 2000 to 2016, netdeposition is recorded over 3.0 m at the upper beach and the area adjacent to the dike (Zone 1), while erosion up to 1.0 m in Zone 2. In conclusion,the results at the Daehang-ri intertidal flat clearly revealed that its topographic changes were induced by the artificial structures and water massesthrough its sluice gate. Counter-clockwise gyre newly created after the sea dikes construction probably results in relocating of sediment outside thedike 1 by transportation of materials eroded from the south to the north along the coast.