• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.2
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• pp.127-137
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• 2003

The researches on the construction of artificial coastal wetlands have been progressed in order to cope with the situation that the area of Korean tidal flat has been reduced due to several coastal developments This study, as a part of the project on construction of the artificial tidal flats, deals with the comparison of the geotechnical characteristics between natural tidal flat and artificial tidal flat, and is also focused on the stability analysis of tidal flats. Various laboratory tests were performed using disturbed and undisturbed samples, which were obtained from a sandy tidal flat in Korea. The stability of the sandy soils accumulated on the tidal flat was investigated by comparing the shear strength of soil evaluated from laboratory test with induced shear stress due to both current and wave action.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.36-37
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• 2014

Construction work in island areas requires the materials to be transported by ship and plane, and it causes an increase in the construction costs. In addition, the construction work near marine zones may produce the marine pollution due to the harmful substances in the cement. Recently, nature-friendly construction materials are increasingly used, and there is a need to select and develop appropriate construction materials. In this study, the compressive strength, tensile strength, flow and chloride content of the mortar mixed with cement and muddy tidal flat were measured to reduce the amount of cement by applying the natural materials, muddy tidal flat and marine sand, and the results were provided as the basic construction material data.

• Ocean and Polar Research
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• v.28 no.4
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• pp.361-368
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• 2006

The Saemangeum tidal flat with an area of approxirnately $233km^2$ is one of the biggest estuarine tidal flats on the west coast of Korea. Because of its location in the estuary of Mangyeong and Dongjin Rivers, the tidal flat receives large amount of sediments. A 33-km long sea dyke, enclosing a coastal zone of $401km^2$, was constructed to reclaim tidal flat in the Saemangeum area. The dyke construction radically changes the local tidal current regime and estuarine circulation. These have an effect on sedimentary environments in the tidal flat. On the tidal flats of the study area net deposition occurred, but net erosion occurred near tidal channel in 2004. The comparison of topography and surface sediments in summer 2004 with those in summer 1988 before the dyke construction showed that elevation increased with maximum 80cm and mean grain sizes were fining at Gwanghwal tidal flats. Sedimentary facies of two cores from Gwanghwal tidal flat revealed homogeneous layers in the upper part suggesting rapid deposition after the dyke construction. The sedimentation rate in Gwanghwal tidal flat(GW 6) using $^{210}Pb$ analysis was about 5.4cm/yr which is well matched with the sedimentation pattern revealed by change in topography.

• Journal of Environmental Impact Assessment
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• v.23 no.2
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• pp.150-156
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• 2014

The aim of this study is to detection of changed vegetation area of Saemangeum tidal flat with comparison of topography and surface sediments during the dyke construction. Sedimentary facies of four seasons of 2001 from inside Saemangeum tidal flat revealed homogeneous layers in the upper part, however near sea side tidal flat were detecting with carried out rapid sediment deposition during the dyke construction using satellite image spatial analysis. The sedimentation types inside Saemangeum tidal flat were classified with vegetation types, which were well matched with the sedimentation pattern revealed by change in vegetation patterns.

• Ocean and Polar Research
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• v.24 no.4
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• pp.331-343
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• 2002

The southern tidal flat of Kanghwa Island with an area of approximately $90km^2$ is one of the biggest flats on the west coast of Korea. Surface sediments for sedimentary analyses were sampled at 83 stations in August 1997, September 1999 and August 2000. The very poorly-sorted mud sediments were predominant in the eastern part of the tidal flat, whereas the poorly-sorted sand-mud mixed sediments were dominant in the western part. The area of muddy sediment distribution diminished, but that of sandy mud sediment extended to southeastward tidal flat for three years. In the western part of tidal flat, deposition occurred during the period of spring to summer, whereas erosion occurred in winter. Sediment accumulation rates during three years indicated that the sediments deposited continuously in the eastern part of tidal flat, whereas eroded in the western part of tidal flat. Recently, construction of artificial structures such as new airport, island-connecting bridges and dikes near the tidal flat might change tidal current and river flow pattern. In order to reduce the ecological damage and to preserve tidal-flat environment, it is necessary to Investigate long-term impacts on sedimentary environment and ecology.

• Journal of The Geomorphological Association of Korea
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• v.25 no.1
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• pp.31-45
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• 2018

This study investigated the characteristics of sedimentary environment changes across a tidal flat in Gagyeongju of Anmyeondo Island. We performed a spatio-temporal analysis on the grain sizes composition of sediments and micro-landform changes during the winter from 2013 to 2016. The results showed that erosion was a dominant processthroughout the study flat, reducing the surface elevation even by 1 m around the upper sand flat. As a consequence, headlands have formed in the entire region of Gagyeongju village. In addition, erosion quickly progressed along the low-lying subtidal zone and tide way and, in contrast, sedimentation progressed in the mid-elevation tidal flat. We posit that a jetty, which had been constructed as a pier facility on the eastern part of the study area, interfered with the flow of tidal current, thereby enhancing these erosional processes. This is because such interference can block the supply of fine-textured sediments from the nearby Cheonsu Bay and therefore reduce surface elevation. According to the surface sediment analysis, the sediments were categorized into 7 sedimentary facies, and generally displayed a high ratio of silt and clay. The result of time-series analysis (2012-2013) showed that the sediments on the tidal flat became fine-grained, and that sorting became worse. However, the sediments on the subtidal zone, embayment and along inside of the jetty tended to be coarse-grained. In conclusion, the tidal flat microlandform change in the study area was caused by a disruption in the seawater circulation due to the jittery construction within the tidal flat, which had a direct effect on erosional and sedimentary environment processes.

• Journal of Environmental Impact Assessment
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• v.20 no.3
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• pp.349-356
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• 2011

This research is aim to analyze of changing landscape and according to phenological cycle from image information of coastal environment obtained by multi-media were analyzed by camera and satellite image. The digital camera and satellite image were used for tidal flat vegetation monitoring during the construction of Sihwa lake. The vegetation type and phenological cycle of Sihwa tidal flat have been changed with the Sihwa lake ecosystem. The environment changes of Sihwa tidal flat area and ecological change were analyzed by field work digital camera images and satellite images. The airborne, UAV and satellite images were classified with the changed elements of coastal ecological environment and tidal flat vegetation monitoring carried out the changed area and shape of vegetation distribution with time series images.

• Journal of Environmental Science International
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• v.8 no.5
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• pp.587-592
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• 1999

The purpose of this study was to identify the controlling factors to construct tidal flat ecosystems having similar characteristics as natural ones. We transplanted the soil in a constructed tidal flat to a natural one and vice versa. Parameters monitored after these transplantations were silt content, organic matter, bacterial population and oxidation-reduction potential. Moreover, the relationship among silt content, organic matter and bacterial population was investigated by laboratory column experiment. The silt content, organic matter, bacterial population and vertical profile of oxidation-reduction potential in the soil transplanted from the constructed tidal flat to the natural one changed to similar values to those in the natural one. On the contrary, all the parameters for the soil transplanted from the natural tidal flat to the constructed one changed to similar values as those in the constructed one. The silt contents in thses two transplanted solis were in proportion to the organic carbon contents and bacterial population. Similarly, the bacterial population in laboratory column experiment increased with the increase in silt and organic matter contents. It seemed to be important to select a place to enhance accumulative of silt and/or to maintain the silt content by hydrodynamic control of seawater in order to construct a tidal flat having similar characteristics as natural one.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.5
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• pp.357-370
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• 2009

EFDC, ESCORT and MIKE21 models are applied at the Gomso Bay to investigate each models' facilities of tidal flat simulation. Comparisons with observation data show that all models simulate hydrodynamic phenomena and tidal flat well. CPU time and WCM are examined to evaluate the efficiency of the models, and the effects of flooding/drying depth and bottom friction are examined to analyze models' facilities of simulating tidal flat. The EFDC model is considered to be fairly good in accuracy, stability and applicability, it is, however, poor in efficiency and its complexity. While the ESCORT model is superior to the EFDC in simulation of tidal flat, it is inferior to the EFDC in CPU time and simulation of bottom friction. The MIKE21 model is excellent in efficiency, but some numerical noise would be detected at low water, not permitting correction of the model.

• KCID journal
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• v.10 no.1
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• pp.73-79
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• 2003

The purpose of this study is to suggest a simple estimation method of tidal flat areas using multi-temporal Landsat TM images due to the progress of sea dike construction for tidal land reclamation. As a case study, Hwa-ong project in which dike construct