• Korean Journal of Environmental Biology
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• v.18 no.4
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• pp.411-424
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• 2000

In order to investigate the population structure and dynamics of halophilous springtails and ants at seashores in Korea, we made quantitative collection from three different sites having different vegetation and environment. The pH, salinity, and electric conductivity of the three sites were measured in order to find environmental factors influencing on their species composition and distribution. In view of the results so far obtained, the species composition and distribution of springtails seemed to depend not so much on pH and vegetation as on soil texture and salinity. On the other side, ant populations seemed to depend on vegetation in sand area and on inundation in both sand area and salt marshes. In all investigated sites, the species diversity in supra littoral zones was higher than in intertidal zones, and among intertidal zones of sand beach and salt marshes it was the highest at the upper zone of the sand beach.

• Journal of the Korean earth science society
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• v.36 no.6
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• pp.533-542
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• 2015

The Gochang beach is located in the southwestern coast of Korea along the eastern part of the Yellow Sea, comprising the Donghori, Gwangseungri, and Myeongsasipri beaches from north to south. The Gochang beach is characterized by macro-tide, open-coast, linear shoreline, and sand substrates. This study has investigated annual and seasonal characteristics of surface topography variation and sediment accumulation rate in the Gochang beach. During the five seasons of winter (Feb.), spring (May), summer (Aug.), and fall (Nov.) in 2014 and winter (Feb.) in 2015, the topographic elevation of total 315 sites was measured along three survey lines. It consists of 21 sites at 30 m intervals in each transverse line perpendicular to the shoreline, respectively. Annual accumulation rate of the Gochang beach in 2014 was -0.081 m/yr, indicative of erosional condition. Annual accumulation rates of the comprising beaches represent -0.091m/yr of the Donghori, -0.051 m/yr of the Gwangseungri, and -0.10 m/yr of the Myeongsasipri.

• Korean Journal of Remote Sensing
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• v.22 no.4
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• pp.243-253
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• 2006

As the ocean and beaches have suffered from the losses of sand, it is necessary to monitor the zones that are prone to erosion continuously with the object of the long-term management. However, each ward offices are busy trying to supply sand without analyzing the marine and beach topographic changes. Therefore a long term effect of erosion has not been shown. In this study, we proposed methods to collect accurate spatial data of the oceans and beaches through sounding and GPS surveys, and detected and analyzed topographic changes quantitatively and qualitatively, by using an integrated RS and GIS techniques. The result of this study revealed that the marine topography has been eroded for 25 years, because of the straight construction of the river and the vast development of urban features, in addition with change of the mean depth 0.40 m, the water surface area 11,028 $m^2$, and submarine volume 2,207,884 $m^3$. The beach topography has accreted for 5 years and the change of the mean elevation is 0.27m, the area 6,501 $m^2$, and volume 25,667 $m^3$, because of the installation of geogrids and the seasonal effect. We conducted monitoring works on the topographic survey of the ocean and beaches and analyzed the present condition of the coastal erosions. Therefore, it is estimated that necessary information on the supply of sand, the safe marine leisure and the management of bating place could be provided.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.6
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• pp.444-452
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• 2009

Textural parameters were calculated from the surface sediments collected from Jinu-do beach in Nov. 2005 and May 2006. In Nov. 2005 and May, 2006, the grain size distribution of surface sediments shows that the mode of $3.0\phi$(i.e., 0.125 mm) dominated the west beach of Jinu-do, but in the east beach the mode of $3.0\phi$(i.e., 0.125 mm) decreased and the mode of $2.5\phi$(i.e., 0.177 mm) was apparently distinct, resulting in the more coarsening trend. Mean grain size of surface sediments also indicates little difference in the west beach between two investigations, but the increasing difference between mean grain sizes in the east beach, showing more coarsening pattern. Such seasonal pattern corresponds to the positive skewness in the east beach in May, 2006. As a result, after the winter in 2005, the surface sediments in the west beach of Jinu-do experienced a little variation, whereas the apparent coarsening of surface sediments occurred in the east beach by removal of $3.0\phi$(i.e., 0.125 mm) fine-grained sand particles. The observed seasonal change may be attributed to the different hydrographic condition and sediment delivery/removal on the surface sediments between the west beach and the east beach of Jinu-do through the increased precipitation and more freshwater discharge from the Nakdong River during the summer and the intensified wave and tide during the winter in the Nakdong River estuary.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.7
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• pp.920-926
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• 2019

In this study, we analyzed the erosion variation of beach area at Haeundae Beach after coastal improvement project using video monitoring system operated by the Coastal Erosion Monitoring (Ministry of Oceans and Fisheries). Haeundae Beach was well maintained and stabilized following large scale nourishment through coastal improvement project despite of seasonal fluctuations. However, multiple typhoons over the last two years caused beach stabilization patterns and seasonal fluctuations to lost equilibrium, resulting in rapid erosion. In particular, the sandy beach was eroded by typhoon Solic and Kongray in 2018 and failed to recover beach area in winter by seasonal fluctuations. And due to multiple typhoons in 2019, the beach area was reduced 9.5 % (12,607 ㎡) year-on-year. According to analyze the observed wave and beach area data in Haeundae, the tendency of erosion and sedimentation was influenced by seasonal incident wave direction for each section(west, center and east part). Therefore, to identify the causes of decreasing seasonal fluctuation characteristics and continuous erosion, hereafter, more precise monitoring of different factors are needed, such as the crest heights of submerged breakwater and its loss of function, and sand leakage to the outside around submerged breakwater.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.3
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• pp.26-36
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• 2003

Collected and analyzed the coastal processes at the estuary of Nak-Dong river and its near coastal area from the history of field measurements. Introduced a numerical model to predict three dimensional topographical change which are evaluated from the nearshore wave and the wave induced current fields for the objective area, and later it were related to the development of beach and shoals. With the comparison between measured and calculated, we found that the changes on the coastline and sand spit and bar development are induced not only by artificial forces due to the construction of river dike, but also by the strong impact of wave induced current. In future days, it is expected that coastline change and sand bar development at the lee side of Jinwoo-Deung and at the front of Dadae beach.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.4
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• pp.292-303
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• 2011

A new type of sand bypassing system is proposed for recovering the eroded beach in this study. This system provides an added methodology to the soft defence which is main recovery method for the coastal shore protection in the world. The study proposes a conceptional design and manufacturing procedure for the relatively small size machine of sand bypassing. In order to get the discharging volume information, the power capacity of the system is tested in the field. The discharge rate of the new system shows up to the expected maximum of 618 ton/hr which is 9.6% lower than that by theoretical calculation. It gives a resonable agreement in this system when the flow is assumed to be of the high density. In this study, the delivering volume of sand is estimated according to the discharge rate. The combination of 300 mm(12 inch) intake and 250 mm(10 inch) discharge pipe line has the pumping capacity of $103\;m^3/hr$ which is nearly the same as that of South Lake Worth Inlet sand bypassing system, Florida, U.S.A.. The proposed system added the mobility to its merit. The unit price of Florida's sand bypassing is $$8~9/m^3$ (US). The system would be economically suitable for small volume of sand because no additional equipment is necessary for the intake. The diesel fuel of 25~30 l/hr was consumed during the system operation. The multiple working system would be the next investigation target for large volume of sand.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.3
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• pp.133-149
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• 1975

1. A quantitative ecological investigation of the intertidal sand beach at Yong-ho Bay, located about 6km NE of Busan Harbour was carried out from February, 1974 to February, 1975. Composition of the fauna, diversity, faunal affinity and distributions in time and space were studied. Some ecological factors influencing to the community also discussed. 2. The beach can be classified as a fine-sand beach which is dominated by Armandia lanceolata and Nephtys sp. (A). Thirty two species of animals representing 29 genera were found. In number, two polychaetes, A. lanceolata and Nephtys sp. (A) were dominant, while one polychaete, Neanthes japonica and one bivalvia, Laternula limicela were dominant in weight. 3. Distribution of the fauna was devided into three areas of different faunal compositions with sediment types particularly by mud fraction content, and it well agreed with faunal affinity and diversity index value. 4. Seasonal fluctuation of the three dominant species, A. lanceolata, Nephtys sp. (A) and N. japonica was studied. Except Nephtys sp. (A), the fluctuation were closely related to the brooding time. 5. There was no relationship between faunal distribution and organic matter content. Submergence time affected the distribution of some species but the influence to the whole-community was little.

• The Korean Journal of Malacology
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• v.26 no.1
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• pp.19-31
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• 2010

Seogundo is a small island adjacent to the southern coast of Jeju Island and connected to it by a boulder beach at low tide Surveys of this area were conducted from 2001 to 2009 to enumerate the mollusks there and also to examine their diversity, relative abundance, and ecological relationships. Both the boulder beach itself and several large tide pools were studied, including the coarse sand substrate and several species of seaweed and coralline algae found in the tide pools. Of the 121 species obtained or observed, there were 97 gastropods, 16 bivalves, and 8 polyplacophorans. Live specimens were obtained for about half of those species. About one third were found on rocky substrate, with the most common species being Nodilittorina radiata and Nerita japonica in the upper intertidal zone, N. radiata and Littorina brevicula in the middle intertidal, and Turbo (Lunella) coronata coreensis and Acanthopleura japonica in the lower intertidal and shallow subtidal. The seaweeds and coralline algae contained about 40% of all mollusk species. The most common mollusks in two species of brown seaweed were Ittibittum parcum, Musculus nanus, and Euplica scripta. In a species of red seaweed, Komaitrochus pulcher was the most frequent, as in the coralline algae, along with M. nanus. The coarse sand in the tidepools contained about 25% of the species, with the Cerithiidae having the largest number. A sample of beach drift contained 17 species, with Bittium aleutaceum and Rissoina (Phosinella) pura being most common. Most species, about 60%, were found in a variety of habitats, especially the marine flora; few species exhibited any habitat preferences. Biographically, Jeju Island is part of the Warm Temperate Northwest Pacific Province and the East China Sea ecoregion with a strong faunal affinity with southern Japan, eastern China, and northeastern Taiwan. Zonal-geographical groupings reveal that the fauna is mainly subtropical-low boreal, preferring moderately warm water, with a somewhat smaller number of tropical-subtropical species.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1407-1414
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• 2009

In this study, a Jeju sand, which contains both siliceous and calcareous materials, was sampled from a beach in Jeju Island. It is observed that the Jeju sand has high extreme void ratios due to the angularity of grains and the intra-particle voids of hollow particles. From cone penetration test using calibration chamber system, it is found that the cone tip resistance($q_c$)-relative density(Dr)-vertical effective stress(${\sigma_v}'$) relation of Jeju sand almost matches to that of high compressible quartz sand. However, this correlation overestimates the relative density of a coastal sediments in Jeju Island maybe due to the cementation effect of this area. From analysis of the results of cone penetration and SPS tests at a coastal area in Jeju Island, it seems reasonable to assume that the coast of Jeju Island is a natural cemented sediments.