• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.4
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• pp.212-222
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• 2011

Estuaries have been used competitively and exploited for the past decades in Korea. To preserve the environment of the estuaries from the integrated perspective, new policies have started to change such exploitative development in 2000s. Due to the poor knowledge-base, however, there has been a lack of support system which enables to execute such policies effectively. The present study was conducted to figure out the limits of the estuarine management research projects in Korea, which is being performed to overcome these limitations. It was studied through Gap Analysis between domestic and foreign advanced practices as well as Analytical Hierarchy Process on expert survey in terms of the three aspects: how well the estuarine management research projects in Korea meets the demands of policy making and administration; raises the awareness of citizens about the merit of environmental preservation; and establishes knowledge-based support system. This project turned out to reflect adequately the development of programs for building estuarine management systems. But consideration of other ministries was relatively scarce. But the contents which directly support community-based activities and educational programs to improve citizens' awareness were judged to be insufficient. According to the results of Gap Analysis, research about the structure and function of estuarine ecosystems, which can support to develop policy alternatives in detail, was relatively more necessary. Therefore, to support estuarine policy management effectively, the development of a realistic plan, which can overcome fundamental issues inherent in the Korean environmental management system and the limitation of the estuarine management research projects in Korea itself, is needed.

• Geomechanics and Engineering
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• v.36 no.2
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• pp.121-130
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• 2024

Many foundation projects are built on red-bed soft rocks, and the damage evolution of this kind of rocks affects the safety of these projects. At present, there is insufficient research on the damage evolution of red-bed soft rocks, especially the progressive process from mesoscopic texture change to macroscopic elastoplastic deformation. Therefore, based on the dual-porosity characteristics of pores and fissures in soft rock, we adopted a cellular automata model to simulate the propagation of these voids in soft rocks under an external load. Further, we established a macro-mesoscopic damage model of red-bed soft rocks, and its reliability was verified by tests. The results indicate that the relationship between the number and voids size conformed to a quartic polynomial, whereas the relationship between the damage variable and damage porosity conformed to a logistic curve. The damage porosity was affected by dual-porosity parameters such as the fractal dimension of pores and fissures. We verified the reliability of the model by comparing the test results with an established damage model. Our research results described the progressive process from mesoscopic texture change to macroscopic elastoplastic deformation and provided a theoretical basis for the damage evolution of these rocks.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.358-362
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• 2009

The coastal zone is the transitional area between land and sea. It plays an important role in the land-sea ecosystem. Unfortunately, most of the world's coastal areas are polluted due to the human being activities. Pollution and development are changing coastal habitats, and feeding and nursery areas are being destroyed, reducing fish and wildlife populations. The pollution in coastal areas is becoming a global environmental problem, more and more attention has been paid to coastal areas. America passed the Coastal Zone Management Act (CZMA) in 1972, and from then, CZMA outlined and conducted the National Coastal Zone Management Program and the National Estuarine Research Reserve System which including 34 projects. And England established "the Crouch & Roach Estuary Project" in 2003, and "South East Coastal and Marine Project" was started in 2007 in responding to the non-point pollutants challenge.

• Journal of Wetlands Research
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• v.14 no.3
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• pp.375-384
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• 2012

The sedimentary processes of the Ganghwa tidal flat has been changed over 20 years because of the large-scale construction projects. The sedimentary environment of the Donggum tidal flat, located in the eastern part of Ganghwa tidal flat and in the lower reaches of Yeomha channel, was affected by changes the tidal current regime and estuarine circulation. These resulted an occurrence of rapid deposition in the tidal flat. The silt-clay laminated silt facies in the upper parts of two core sediments suggested that deposition had been relatively high in the tidal flat. The sedimentation rates from the cores using $^{210}Pb$ analysis were 3.25cm/year(st. 3) and 3.47cm/year(st. 5). However the short-term sediment accumulation rates from 2010 to 2012 were mostly less than 1cm/year, indicated that the sediments deposited relatively low rates. As a result, the sediment in the Donggum tidal flat rapidly accumulated during 2000s due to constructions of man-made structures. Recently, the increase of elevation in the tidal flat resulted to show relatively low sedimentation rate with seasonal variations.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.687-697
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• 2019

By monitoring sediment grain size and level variation of tidal flat surface for 6 years (2005-2011), and also by mooring TISDOS (tidal-flat sediment dynamics observation system) on the low intertidal flat in 2008, we investigated the sedimentary environment of tidal flat in the dammed Yeongsan River Estuary. The tidal flat of the Yeongsan River Estuary lost 82 % of its area because of coastal development projects, and a narrow tidal flat below mean sea level now remains. Most of the tidal flat sediments are composed of silt up to 70-94 %, and show the characteristics of clay deficiency and silt dominance. This is closely related with the coastal development, which led to the destruction of high tidal flats where most mud settled, and the modification of tidal current patterns. Moreover, the estuarine tidal-flat sediments reveal seasonal variation. They are coarse with abundant silt during windy autumn to spring, fine with abundant clay during the less-windy and high-discharge summer. This phenomenon indicates that the behavior of sediment particles on the low intertidal flats of the Yeongsan River Estuary is influenced by wind waves for silt and fresh water discharge and the tidal process for clay. Monitoring results of the altitude of tidal flat surface showed that the study area had eroded at an average rate of -2.6 cm/y during the period of 2005-2011, and also that an unusual deposition with a rate of 4 cm/y occurred in 2010. The erosion can be explained by an increased tidal amplitude and a strengthened ebb-dominant tidal asymmetry after the construction of an estuary dike and the Yeongam Kumho Seawall. The deposition in 2010 seems to have been closely related to the mass production of suspended materials from dredging of the estuary.