• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.47-47
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• 2011

하도 내 수역이 식생으로의 천이가 진행되고 최종적으로는 육상 식물들이 활착하게 되는 육역화 현상은 하도의 수리학적 문제 및 환경생태적 측면에서 큰 문제를 발생시킬 가능성을 내포하고 있다. 최근 하천복원의 필요성이 강조됨에 따라 물골공법 및 국부세굴 유도형 공법 등 실용성을 포함시킨 다양한 하천 복원공법이 제시되고 있다. 물골공법은 자연적인 물골형상에 의한 유사퇴적방지, 홍수시 유속저감 및 생물서식처를 조성하는 하상 생태복원 공법을 의미하며, 본 연구에서는 수리모형실험 및 3차원 수치모의를 이용하여 다양한 하도육역화 방지 공법 중 물골공법의 효과 및 적용성을 검토하였다. 물골공법의 특성 중 유사퇴적방지의 효율성 분석을 위해 부정류(unsteady state)상태에 대해 연구를 수행하였으며 홍수 이후 수위하강시 고수부지 및 물골 주변에서의 흐름특성을 재현하였다. 수위하강 모의를 위해 임의의 수위하강시간을 선정하여, 수위하강이 진행되는 시간( )을 각각의 수위하강시간으로 무차원 화한 후 무차원된 시간(t/�� )에 따른 흐름특성을 비교 분석하였으며 모의 및 분석결과, 수위하강시간이 80초 이상일 경우 주요 지점에서의 유속의 변화는 무차원된 시간에 대하여 일치하였으며 수리모형실험 및 수치모의에 적용할 수위하강시간으로 선정할 수 있었다. 물골 전구간에 대한 부정류 실험을 위해 LSPIV(Large-Scale Particle Image Velocimetry)장치를 이용하여 수위하강에 따른 물골주변의 흐름특성을 관측하였으며 3차원 수치모의를 통해 검증하였다. 실험 분석결과, 수위하강에 따라 고수부지 위로 흐르는 유수가 물골 내부로 유입되어 물골을 따라 흘러 물골 합류부로 이동하는 것으로 나타났으며, 이는 홍수시 유수와 함께 떠다니는 부유사(suspended load)가 물골로 유입되어 물골 합류부로 이동하므로 물골의 유사배제 가능성을 판단할 수 있었다. 또한 물골의 유사배제능력을 평가를 위해 실험을 통하여 산정된 최대 및 최소 마찰속도(U )와 유사이동 한계곡선을 이용하여 물골의 통한 배제 가능한 유사의 입경을 분석하였다. 분석결과, 최소 2mm에서 최대 4mm로 나타났으며 이 입경 이하인 유사에 대해서는 퇴적되지 않고 물골을 통하여 배제될 수 있을 것으로 예상되었다. 본 연구 결과 물골공법 적용시 수위하강에 따라 물골에서 하도방향으로 유사의 수세(flushing)효과가 나타났으며 유사의 부상 및 이송이 효과적으로 발생하여 고수부지 내 유사퇴적 방지가 효과적인 것으로 판단되었다. 추후 다양한 형상의 물골에 대한 능력검토가 보완된다면 물골설계지침 제안을 위한 자료로 활용 가능할 것이다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.1
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• pp.31-41
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• 1997

This study was carried out to investigate the composition and the distribution of the benthic community in the coastal area of Inchon seasonally from May 1994 to February 1995, and to estimate the environmental factors that effect the temporal and the spatial changes of benthic species composition. In the present study, 231 species were collected with the average density of 455 ind./$m^2$. The dominant species were Heteromastus sp., Sternaspis scutata, Chaetozone setosa, Mediomastus sp., Glycinde sp., Glycera sp. and Nephtys oligobranchia, which are in the polychaete group; abundance of these species showed seasonal and spatial variations. The study area was divided into 4 regions by cluster analysis such as outside area of Palmido (I), main channel region and adjacent are of Shihwa sea wall (II), north-eastern area of Youngjongdo (III), and the Inchon harbor and the mouth area of Sorae harbor (IV). The particle size of sediment which generally influences the distribution of the benthic community, the differences of the concentration of heavy metals, and of the dissolved oxygen, the increase of the proportion of polychaetes and molluscs, the absence of the crustacean phoxocephalids, and the increase of the abundance of pollution indicator species, indicated that the environment of the areas have been degrading gradually from Group I to Group IV.

• The Korean Journal of Mycology
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• v.27 no.4 s.91
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• pp.289-292
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• 1999

We investigated the isolation method of mushroom infesting pests, Lycoriella mali, Coboldia fuscipes, Histiostoma sp. from mushroom-growing compost. Sugar solution of different densities (0, 10, 20, 30, 40, 50%) was tested to provide a means of seperating mushroom pests from the compost media. Thus, 40% sugar solution was suitable for isolation. The sieve size to entrap the pests was $30{\sim}140$ mesh; Lycoriella mali was trappped mainly $30{\sim}65$ mesh sieve, Coboldia fuscipes was caught mainly $30{\sim}100$ mesh sieve, Histiostoma sp. was trapped mainly $65{\sim}140$ mesh sieve. An isolation procedure was as follows; The infested compost was disintegrated in water and poured onto a set of 16, 30, 80, 140-mesh sieve. The material caught in the sieve is added in 40% sugar solution and then most compost particle were massed at the bottom while the supernatant contains mushroom pests. The upperlayer material was poured into a Seperatory funnel and the sediment at the bottom is drained off. The remaining material are washed off examination dish for study.

• Journal of the Korean association of regional geographers
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• v.22 no.1
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• pp.211-224
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• 2016

Natural lakes are estimated in variety with that's function or value depending on age environment or geographical characteristics. There are many kind of natural lakes, but the kind of natural lake is limited in rivers in korea flowing into East Sea. However, Yeonho lake in Uljin has different geographical characteristics with oxbow lake or lagoon which is common in korea's river flowing into East Sea. Therefore the purpose of this study is to analyze geographical characteristics due to the process of Yeonho's formation. Further more research for protecting wetland is needed to adequately preserve, depending on the geomorpologic process. To analyze geographical characteristics, it was essential to compare and analyze topographical map of 1918 1956 2012 and I pictured estinated line of bedrock and longitudinal section of Nam-dae cheon(Riv) Yeonho cheon(Riv). In addition, I denoted flooded areas through design flood level of Nam-dae cheon(Riv) Yeonho cheon(Riv) and analyzed particle size distribution of deposited sediment due to consider deposit environment. The results of study are as follows. In conclusion, Yeonho lake is floodbasin which was not researched at river flowing into East Sea. Through this study, my opinion is that floodbasin can be formed in the river that is steep and short. I argue that preservation methods will be seeked by geomorphologic process of floodbasin and development of downtown.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.299-309
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• 2019

This study was designed to assess the quality and quantity of food resources such as the chlorophyll a concentration (Chl-a), the particulate organic carbon (POC) and the particulate organic nitrogen (PON), on blood cocke (Tegillarca granosa Linnaeus) farms from May to November 2017 in the northwestern area of Yeoja Bay, Korea. The values of Chl-a, POC and PON were $1.69-7.68{\mu}g{\cdot}L^{-1}$ (average: $3.48{\mu}g{\cdot}L^{-1}$ in the surface), 0.88-2.58 mM (average: 1.97 mM) and 0.17-0.90 mM (average: 0.54 mM), respectively, and these values were higher in the spring and summer and lower in the autumn. Furthermore, Chl-a and POC had higher values on the bottom layer than those vales on the surface, while PON had higher values on the surface than those values on the bottom. The POC/PON ratio and POC/Chl-a ratio were 1.56-7.88 (average: 3.71 on the surface of the water) and 216-967 (average: 700 on the bottom of the water), respectively, with most of the carbon sources being sediment-accumulated particle organic matter, and the contribution by phytoplankton was assessed as being low. These results show that the food source of the blood cockle farms in the northwest area of Yeoja Bay seems to be abundant in quantity, but this is considered to be very poor in quality.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.2
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• pp.15-24
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• 2021

For the aquaculture industrialization of surf clam (Tresus keenae), it is important to basic data on the marine environment of the habitat of surf clam (T. keenae). In this study, we investigated the marine environment of habitat of surf clam (T. keenae) and sought to basic data for the preparation of surf clam (T. keenae) for artificial seed production. The water temperature of the habitat of surf clam (T. keenae) was the lowest in winter and appeared high in summer. The salt concentration showed it range from 31.2 to 33.9 psu. The pH showed it range from 7.69 to 8.70, with high pH in winter and low pH in summer. The dissolved oxygen(DO) was showed it range from 6.20 to 10.24 mg / L and the autumn was relatively higher than the spring and winter. The species composition of phytoplankton was about 30 to 40 species, and most of them were diatoms. The abundance of seasonal phytoplankton showed it range from 23.5 to 61.3 cells / ml, showing seasonal differences. The expression of dominant species also showed a difference depending on the season. As for the particle size composition of the sediment, sandy silt was the most distributed. Flow velocities appeared at 50-80 cm / s in the southeast direction at ebb tide and at 60-100 cm / s in the northwest direction at flood tide. The results of this study can be used as basic data for providing knowledge about the habitat and marine environment of surf clam (T. keenae) and for studying shellfish that inhabit the sedimentary layer.

• Land and Housing Review
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• v.13 no.3
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• pp.125-140
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• 2022

Road Deposited Sediment (RDS) is the solids formed from the wear of road, wear of vehicles, exhausts, and the input of the emissions from various sources out of the roads. RDS is seriously polluted by organic matter, nutrients, and metals. RDS plays an important role as the sink and the transport medium of the associated pollutants because RDS can be carried to the adjacent water system via stormwater runoff. In this regard, the heavy metals in RDS were investigated based on the publications. The contents of the metals in RDS were highly variable. The concentration of Cr, Ni, Cu, Fe, Zn, As, Cd, and Pb in urban RDS in various regions was in a range of 3.16-3,410, 1.15-1,382, 20.2-9,069, 2,980-124,853, 81-2,550, 2.3-214, 0.19-21.3, and 15.21-1,125 mg/kg, respectively. The anthropogenic enrichment of the metals in RDS was confirmed by the high concentration of Cu, Zn, Cd, and Pb. The contents of the metals were higher in industrial and traffic areas than in residential areas, while they were generally increased with decreasing particle size. It is believed that this study's results would contribute to quantifying the metals' load via RDS and establishing control strategies.

• Journal of Marine Life Science
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• v.8 no.1
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• pp.68-77
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• 2023

In this study, we investigated the quantitative distribution of microplastics in the surface seawater at 8 points near the Taean Peninsula using fluorescence staining. The study revealed a detection range of microplastics from 0 to 360.5 particles/l, with an average of 149.7 ± 46.0 particles/l. When classifying the microplastics by size, it was found that particles smaller than 50 ㎛ were dominant, although there were differences at Site 3. Moreover, it was not possible to identify clear correlations when comparing the number of microplastics based on collection area and particle size. Various physical and chemical factors, including plastic material, dynamic ocean conditions (such as currents, wind, waves, tides), geological characteristics (topography, slope), sediment materials including coastal organisms, human activities (fishing, development, tourism), and weather conditions (floods, rainfall), affect the behavior of microplastics. Therefore, future efforts should focus on standardizing quantitative analysis methods and conducting fundamental research on microplastic monitoring, including the analysis of environmental factors.

• Journal of the Korean Geotechnical Society
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• v.25 no.11
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• pp.105-115
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• 2009

The Jeju sand was sampled from the beach in Jeju Island and its basic properties were analyzed. The cementation effect of Jeju coastal sediments was evaluated from in-situ tests such as SPT, CPT, and the Suspension-PS test. It was shown from test results that the Jeju sand has high extreme void ratios due to the angularity of grains and the intra-particle voids of hollow particles, similar to typical calcareous sands. From cone penetration test in the calibration chamber, it was found that the cone resistance($q_c$)-relative density($D_R$)-vertical effective stress(${\sigma}_v'$) relation of Jeju sand almost matches that of high compressible quartz sand. However, the $q_C-D_R-{\sigma}_v'$ correlation suggested for uncemented Jeju sand overestimates the relative density of coastal sediments of Jeju Island due to the cementation effect. From the analysis of the relation of cone resistance, N value, and small strain shear modulus measured in-situ, it seems reasonable to assume that the coastal sediment of Jeju Island is a naturally cemented one.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.28 no.4
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• pp.143-157
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• 2023

This study confirmed the characteristics of macrobenthic community due to anthropogenic environmental changes in the Boryeong Jugyo tidal flat, where the habitat of manila clam (Ruditapes philippinarum) and mud shrimp (Upogebia major) is separated. The total number of occurring species was 55 during the study period with an average habitat density of 338 ind./m² and a biomass of 212.2 gWWt/m². The number of occuring species increased from 27 species at the upper flat to 37 species at the lower flat, and the dominant species differed by tide levels (Upper: Leonnates persica, Middle: Heteromastus filiformis, Lower: R. philippinarum). The macro-benthic community sturctures of the top 10 species using cluster analysis and nMDS were divided into two groups, focusing on Manila clam culture farm of lower flats and middle flats with high habitat density, reflecting the influence of specific species. The sediment composition of the U. major habitat space fluctuated highly, but it was maintained annually, and the sorting coefficient was 2.1 𝜑, and the proportion of the same particle size was increased. In particular, because the middle flat has a dense anthropogenic impact, a dominant species, H. filiformis dominated and revealed a relationship with the density of burrow holes of U. major, which is considered to be a biological interaction between these two macrofauna in this tidal flat.