Long-term Changes of Sedimentary Environments at the southern Kanghwa Tidal Flat, west Coast of Korea

Abstract

Comparisons of surface sediment distributions and elevations on the tidal flats for nearly 15 years had been used for understanding long-term changes of sedimentary environments at southern Kanghwa tidal flat, west coast of Korea. The mud sediments dominated in the eastern part and sandy mud sediments governed in the western part of the tidal flat in summer 1997. The distributed area of mud sediments had decreased, but that of sand-mud mixed sediments extended to eastward tidal flat in summer 2011. The calculated transport vectors with grain-size parameters showed that the sediments transported eastward and then deposited in Sunduri and Tonggom tidal flats in 1997. However, the sediment transport vectors directed toward the middle part of Tongmakri tidal flat in 2011. The long-term topographic changes showed that deposition occurred with net deposition of 0.70m and 0.16m at Tongmakri and Yeochari tidal flats, respectively and erosion occurred with net erosion of -0.09m at Changhwari tidal flat between April 1998 and March 2013. These changes should be effected the local hydrodynamic changes by several constructions near the tidal flat since the 1990s.ediments dominated in the eastern part and sandy mud sediments governed in the western part of the tidal flat in summer 1997. The distributed area of mud sediments had decreased, but that of sand-mud mixed sediments extended to eastward tidal flat in summer 2011. The calculated transport vectors with grain-size parameters showed that the sediments transported eastward and then deposited in Sunduri and Tonggom tidal flats in 1997. However, the sediment transport vectors directed toward the middle part of Tongmakri tidal flat in 2011. The long-term topographic changes showed that deposition occurred with net deposition of 0.70m and 0.16m at Tongmakri and Yeochari tidal flats, respectively and erosion occurred with net erosion of -0.09m at Changhwari tidal flat between April 1998 and March 2013. These changes should be effected the local hydrodynamic changes by several constructions near the tidal flat since the 1990s.