Ha, H.J.; Choi, S.M.; Seo, J.Y., and Ha, H.K., 2018. Erodibility of sand-mud mixed sediment on the Yeochari tidal flat, Gyeonggi Bay, Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 416–420. Coconut Creek (Florida), ISSN 0749-0208.
Yeochari tidal flat is located along the southwestern part of Ganghwa Island in Gyeonggi Bay. The aim of this study is to quantitatively evaluate the erodibility of sediment on the tidal flat. Sediment samples were obtained from two typical sites (mud and mixed flats) in April and June, 2017, and then their erodibilities were estimated by a Gust erosion microcosm system. Erodibility at the two sites was different in April and June. In April (late spring), the total eroded mass of mud flat was 0.023 kg m−2 with clay content of higher than 10%, whereas total eroded masses of mixed flat were 0.027 to 0.029 kg m−2 with clay content of lower than 5%. Thus, the sediment erodibility in mud flat was lower than that in mixed flat during April due to clay content. As the clay content increases, non-cohesive sediments were likely surrounded by cohesive sediments. This induced to enhance the inter-particle bonding and decrease the erodibility. In June (early summer), although the clay content was less than 5%, the mixed flat had the low erodibility (total eroded mass of 0.004 kg m−2), which was about 7 times lower than that in April. The low erodibility in June might be caused by the enhanced armoring effect with increased grain size.