• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1030-1034
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• 2005

The purpose of this study was to clarify the penetration behavior of particulate matters by wave and tidal actions in sandy beach located in enclosed bay and to evaluate the effect of stranded oil on penetration of particulate matters. Experiments were rallied out using a model sandy beach facility. The particulate matters penetrated into saturated sediments by wave action from breaking wave run-up point with a semi-circular forming in low energy beach as enclosed bay. On the other hand, the penetration velocity of the particulate matters was to be faster according to the increase of slope and breaking wave height. The particulate matters by tidal action penetrated into the sediments at an angie of 45 degrees in the direction of porous water flow. The stranded oil completely blocked the penetration of the particulate matters into the sediments. These results indicate that the penetrated oil prevents the penetration of the particulate matters into the sediments and, therefore, results in the reduction in the supply of plankton, bacteria and organic detritus for the benthic organisms in the sandy beach.

• Journal of the Korean earth science society
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• v.37 no.2
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• pp.89-106
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• 2016

The Gochang open-coast intertidal flat is located in the southwestern coast of Korea (the eastern part of the Yellow Sea), characterized by macro-tidal range, an open-coast type, and sand substrates. This study has investigated seasonal variation in sedimentary facies of surface sediments in the Gochang intertidal flat. In the four seasons of February, May, August, and November, 2014, surface sediments of 252 sites in total were sampled and analyzed along three survey lines. The surface sediments of the Gochang intertidal flat in 2014 consisted mainly of fine-grained sand sediments showing a trend in grain size to be coarser in winter and finer in summer. Based on seasonal wave and tidal level data recorded near the study area, it was interpreted that the seasonal effects of wave were stronger than those of tide as a factor controlling surface sedimentation. High waves in winter resulted in the coarsening trend of grain size in surface sediments, whereas, during summer time, the sediments became finer by relatively low waves. Spatial sedimentary facies of the Gochang intertidal flat in 2014 represented that seasonal deviation of the upper tidal zone was larger than that of the lower tidal zone, hence sediments getting coarser in grain size and poorly sorted in the upper tidal zone. From upper to lower tidal zone, the grain size became finer and sediments were better-sorted, showing smaller seasonal deviations.

• Journal of the Korean earth science society
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• v.26 no.3
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• pp.253-267
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• 2005

Seasonal and spatial variations of tidal flat sediments were studied in Yeoja Bay. Results of the yearly observation of tidal flat transect lines indicated that the monthly change of grain size composition was not distinct from each tidal flat transect line, but it was quite clear that clay covered $40\~70\%$ of the sediment composition. Clay composed most highest in the northern part of the bay, and lowest in the western. As clay content increased, water and organic matter showed a tendency of increase, while the mean grain size was fixed per clay amount. Shear strength came out as 0 kPa as a whole. Seasonal variations of clay contents in each tidal flat were higher in winter and spring, but lower in summer and autumn. Thefine sediments were likely to be accumulated in the winter and spring. The average accumulation rate of each tidal flat was $-14.62\~38.57mm{\cdot}yr^{-1}$. The numbers showed $32.13mm{\cdot}yr^{-1}$ in the northern, $-14.62mm{\cdot}yr^{-1}$in the western, and $6.46mm{\cdot}yr^{-1}$ in the eastern part. During the coarse of this study sediment accumulation rates indicated that the sediments deposited continuously in the northern part of tidal flat, whereas erosion occurred in the western part. However, there was no distinct change in the eastern part. It was due to the clockwise lateral circulation in Yeoja Bay. Seasonally, sedimentation happened during the dry season (winter and spring) and erosion during the wet season (summer and autumn).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.2
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• pp.97-107
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• 2003

In order to evaluate the effect of dry-wet treatment on well developed tidal flats along the complex coastal line in the western part of Korean Peninsula, we adopted a finite element tidal hydrodynamic simulation model, ADCIRC incorporating newly suggested dry-wet option and applied it to Chonbuk coastal area and Keum river estuary. Model comparison with observed current data by RMS error in the Chonbuk area shows very good agreement within 1cm/sec of tidal velocity difference and 3％ of error to maximum tidal currents. However there is not seen any significant advantages in dry-wet treatment. For the tidal volume tests in the Keum river estuary, the differences are satisfied within 5％ nevertheless of dry-wet treatment but in a near cross section it marks over 20％. However both results are almost same in tidal residual tests. Thus it can be concluded that dry-wet option is not always necessary in the simulation of long-term dispersion analysis.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.319-322
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• 2002

그라우팅으로 지반 개량된 조간대 퇴적층의 지층구조를 규명하기 위한 방법으로 전기비저항탐사, 굴절법 탄성파탐사, 지하레이더탐사를 실시하였다. 연구대상 지반의 10m 전후 심도에서 해수의 영향을 받는 수평의 저비저항대가 발달하며, 저비저항대는 모래가 우세한 지층에 해당한다. 지반의 탄성파 속도는 1~3km/sec의 범위로 조간대의 미고결 퇴적층과 비교할 때 매우 높은 속도에 보여준다. 지반의 높은 속도는 지반 개량의 효과로 판단된다. 지하레이더탐사에서 퇴적층의 구성 물질에 따라 교반 정도가 달지는데 모래층은 퇴적물과 주입제의 교반이 잘 이루어져 불규칙한 반사면으로 나타나며, 점토층은 교반이 불량하여 개량된 부분은 주상으로 관찰된다. 물리탐사의 결과와 시추조사를 대비할 때 지반 개량은 기반암까지 시행되었으며, 양호한 암반을 지시하는 고비저항대와 고속도층은 내륙으로 갈수록 깊은 심도를 보여준다. 이것은 지반 개량 이전의 기반암 심도와는 상반되는 것으로 지반 개량의 효과는 해안방면의 지층에서 잘 나타난다.

• The Korean Journal of Quaternary Research
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• v.8 no.1
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• pp.1-8
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• 1994

한국서해 경기만 남부 반월조간대 퇴적층에서 망간과구리의 함량특성을 밝히기 위 하여 총 3개의 주상시료를 채취하여 퇴적물의 입자와 유기탄소(organic carbon)함량을 일차 적으로 분석하였고 이에 따른 중요 시료에 대하여 망간과 구리의 함량을 분석하였다. 이러 한 분석결과는 연구지역의 망간함량이 연근해역 퇴적물의 망간함량에 비해 낮고 구리함량은 상대적으로 높다. 연구지역 내에서도 환원환경인 중부와 하부조간대에서 망간함량이 낮고 구리의 함량이 높게 나타났다. 이와같이 반월조간대 퇴적물의 망간 함량이 낮은 이유는 환 원환경에 공급괸 망간 산화물이 수 mm 깊이의 퇴적층에서 용해되고 그결과 생성된 용존 망간이 퇴적층과 해수와의 경계면(interface)으로 이동 제거 되었기 때문이다. 그러나 구리- 유기물 결합체는 퇴적물내에서 분해되고 그결과 생성된 용존구리는 황화물로 재 침전 되기 때문에 높은 함량을 나타내는 것으로 해석된다, 이와같은 결과는 반월 조간대 퇴적층의 초 기속작용의 영향을 받는 것으로 사료된다.

• Journal of the Korean association of regional geographers
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• v.7 no.2
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• pp.82-96
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• 2001

The purpose of this study is to investigate the wise use and the management of intertidal environment. For tills purpose, we selected the Kanghwa island mudflat which is one of the most important intertidal region in Korea peninsula. The main research method is surface sediment and several map analysis. The results are as follows. (1) The study area is worldwide coastal wetland in view of ecology and geomorphology. But most of the salt marsh has been reclaimed since Japanese colonial period, the study area is mainly composed of mudflat. (2) The mean tidal regime of study area is 7.3m. From this tidal regime, the study area is subdivided into four distinct areas: the high intertidal area the middle intertidal area the low intertidal area and the shallow sea area terrestrial area near mudflat. (3) The mean particle size of surface sediment is sand 41.5%, silt 47.3%, clay 11.2%. This particle size pattern indicates the ecological characteristics of surface sediment of the study area. The proportion of clay is increasing to the open sea. (5) The pursuit of the wise use and the management must be implemented by the consideration of not only ecologic and sedimentary characteristics but also of the eco-tour site plan. And the entire use and management subject is different in each area.

• Journal of the Korean earth science society
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• v.27 no.3
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• pp.328-340
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• 2006

In Janghwa-ri of Kanghwa Island morphological changes in four transects, 112 surface, and 2 core sediments were analyzed to understand the seasonal variation of the muddy tidal-flat environment. Sedimentary of facies can be classified into four facies; sand, muddy sand, sandy mud, and silt. During winter, the coarse-grained sediment facies expanded seaward. In the subsurface part of the core sediments, poorly sorted silty sediments dominate the area. According to the Pb-210 isotope analysis, accumulation rates of the tidal flat in Jangwha-ri appear to be $5{\sim}19mm/yr$. In the study area, the result is suggestive of a rapid change in depositional environments in recent years.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.2
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• pp.117-126
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• 1999

Hampyong Bay is a semienclosed and macrotidal bay which opens to the eastern Yellow Sea through a narrow inlet in the southwestern coast of Korea. In order to understand the tidal-flat sedimentation in the semienclosed setting, morphology, sediments, accumulation rate and sea cliff erosion were investigated in the tidal flat of Hampyong Bay. The tidal flat of Hampyong Bay lacks intertidal drainage systems, and generally shows the concave-upward profile whose relief is designated by marked morphological features such as high-tide beaches, intertidal sand shoals and tidal creeks. Surfacial sediments of the tidal flat mainly consist of mud, sandy mud, gravelly mud, gravelly sand and muddy gravel, thus showing the textural characteristics of multimodal grain-size distribution, poorly sorting and positive skewness. The sediments generally coarsen landward due to the increase in coarse fraction content. Sedimentary structures are deeply bioturbated, but parallel lamination and lenticular bedding are locally found in the mudflat near mean low water line. Annual accumulation rates across the tidal flat (along Line SM) average -5.2 cm/yr with a range of -45.8~+4.2 cm/yr, indicating that the tidal flat is erosional. In general, erosion rates of upper and lower tidal flat are higher than those of middle tidal flat. Seasonally, the erosion rates are much higher during spring and winter when dominant wind direction corresponds to the long axis of Hampyong Bay. Sea cliffs are eroded at a rate of 1.4 m/yr. The biggest sea cliff erosion generally occurs 1~2 months later after tidal flats were extensively eroded. Such erosions of tidal Oats and sea cliffs in the semienclosed bay setting are interpreted to be due to wind waves coupled with local sea-level rise.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.331-337
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• 2017

This study was carried out to analyze the community structure and distribution of macrobenthos at the intertidal zone of Jukbyeon in Uljin-gun during 2015-2016. The number of species were total 41 from 5 phyla. The species composition of Cnidaria 4, Mollusca 19, Annelida 3, Arthropoda 13, Echinodermata 2 and the individuals was $1,642inds./m^2$ and the weight was $1,959.42gWWt./m^2$ in the study area. The dominant species of the upper zones were Chthamalus challengeri and Nodilittorina radiata. Those of the lower zones were Mytilus galloprovincialis, Nipponacmaea schrenckii and Chlorostoma turbinata. The dominant species of the upper zones of winter and spring were C. challengeri, the summer and autumn of the N. radiata. Those of the lower zones were all seasonal of M. galloprovincialis. As a result of cluster analysis, those regions were divided in three groups, which were a group A of December 2015, August 2015 and February to August 2016 of intertidal zone lower, group B of December 2016 and May 2015 of intertidal zone lower, group C of intertidal zone upper.