Mud Deposition on a Macrotidal Beach: Dasari Coastal Dune, West Coast of Korea

• Published in: Journal of coastal research 2016-03, Vol.75 (sp1), p.1312-1316
• Main Authors: Chang, Tae Soo, Ha, Hun Jun, Hong, Seok Hwi
• Format: Article
• Language: English
• Subjects: Animal behavior; Beaches; Coastal dunes; Coastal erosion; Coastlines; Coasts; Creeks & streams; Dunes; Energy dissipation; Flats (landforms); Global positioning systems; GPS; Grain size; high-tide sand beach; intertidal mud flat; Intertidal zone; Morphology; Mud; Mud flats; Sand; Sea level; Sediments; SOUTH KOREA SESSION; Studies; Terraces; Tidal flats; tide-dominated beach; Topographic maps; Topographic surveys; Trends; Wave energy; Wave power; Wind; Winter
• ISSN: 0749-0208; 1551-5036
• DOI: 10.2112/SI75-263.1

Chang, T.S., Ha, H.J., and Hong, S.H., 2016. Mud deposition on a macrotidal beach: Dasari coastal dune, West Coast of Korea. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1312 - 1316. Coconut Creek (Florida), ISSN 0749-0208. Along the macrotidal west coast of Korea, numerous pocket-type or embayed sand beaches are exposed to wave energy and strong tidal processes. They are generally characterized by almost 1 km wide intertidal zones and relatively steep beach gradients. Among these, peculiar muddy beaches occur along the Dasari macrotidal shoreline, midwest coast of Korea. The Dasari beach is generally composed of three sectors; a currently eroding inland coastal dune, a steep and narrow sand beach, and a wide, gently seaward sloping intertidal flat. Unlike other sand beaches on tide-dominated coasts, sediments in the intertidal zone show an unexpected shoreward decrease in mean grain size, fine sands on the lower flat getting finer and finally becoming muddy on the upper flat at the transition between the beach and the intertidal flat. Topographic surveys reveal that the intertidal zone is located below mean sea level without the occurrence of any shore-parallel bars, these features being characteristic of wide low-tide terraces. In particular, the mud flats have a smooth morphology, probably leading to extensive wave energy dissipation. The sand on the narrow beach may be associated with erosion of foredunes during storms coinciding with high tide, rather than the influence of onshore transport across the mud flat. The source of both the fine-grained sediments of the mud flat and the sand of the beach is currently still unclear.