한국 남해 여자만의 퇴적물 거동 메카니즘

Abstract

Yeoja Bay, a typical tidal inlet, surrounds Goheung, Yeosu and Godolsan Peninsula in the South Coast of Korea. The bay is meso-tidal environment and morphologically divided into bay-mouth, main tidal channel, intertidal flat and estuary. The bay-mouth is divided into West and Jobal inlet, narrow and deep up to 30m and 40m. The main tidal channel extends in the direction of western part of Jinji Island and the central part of Yeoja Island from inlet. The tidal flat looks more developed in northern part than western and eastern part. Estuary is located in the northern and northwestern of the bay. The purpose of this study is to understand fine-grained sediment behavior in the tidal flat and bay. The surface sediment consisted of five sedimentary facies: silty clay, clayey silt, clay, sand and silty clayey sand. The sedimentary facies in the bay was dominantly silty clay. Measurement of sediment accumulation rates from August 2001 to July 2002 conducted in the northern part(transect line YJ-1, 2), western part(YJ-3) and eastern part(YJ-4, 5) of tidal flat. The short-term changes of sediments on transect lines showed that grain sizes were not distinctly changed but the contents of clay were 40-70% in sediments during observation periods. Generally, the contents of clay were relatively high in northern part and low in the western part of the bay. The seasonal variations of clay contents were relatively high in winter and spring and low in summer and autumn. The average sediment accumulation rate on the tidal flat was -14.62 – 38.57mm/yr, with 32.13mm/yr in the northern part, -14.62mm/yr in the western part and 6.46mm/yr in the eastern part. Fine-grained sediment accumulated in the northern part and eroded in the western part of tidal flat. 25 hour-anchored survey was carried out for measurements of hydrodynamic parameters at the bay mouth (M-1, M-2) and the watershed (M-3, M-4) in May 2000. Depth-integrated net suspended sediment loads (Qs) for two tidal cycl