• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.11 no.1
• /
• pp.50-55
• /
• 1999

Gao and Collins method (two-dimensional sediment transport trend-vector model) using grain-size parameters (mean grain size, sorting coefficient, and skewness) calculated by the statistical moment method is introduced to understand semi-quantitatively the sandy and surficial sediment transport trends on a coast of the East Sea. The result is the sediment transport vectors which indicate transport paths of surficial sediment by wave-induced currents. The corresponding morphological feature is a spit developed at the mouth of the Nam¬dae stream, which is a resultant sediment transported by longshore current and is blocking the circulation of ocean. After this, it is thought that seasonal research and hydrodynamic measurements are needed for verification of the results.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2007.05a
• /
• pp.447-449
• /
• 2007

유해성 적조생물인 C. polykrikoides에 대한 해역별 적조잠재력 평가를 위하여 유해성 적조가 자주 발생하는 남해안의 소리도 부근해역, 광양만, 남해도 주변해역, 거제만, 부산연안의 해수 및 해저퇴적물을 채집하여 배양실험을 실시하였다. 실험을 위한 기본배지는 f/2배지에서 배양조건은 온도 $20^{\circ}C$, 염분 34, 조도 2000Lux, 그리고 실험생물은 대수증식기의 C. polykrikoides를 $300cells/m{\ell}$접종하였다. 해역별 해수에 대한 적조생물 성장은 광양만에서 가장 높아 적조발생 잠재력이 가장 높았고, 다음은 부산 기장, 거제, 남해연안 순서로 성장이 높게 나타났으며, 질산성 질소 농도는 $0.35{\sim}24.74{\mu}M$ 범위로 적조생물의 성장과 같은 순서를 나타내었다. 한편 해저 퇴적물 용출액은 적조생물의 성장을 현저히 촉진시켰으며, 남해도 미조연안의 해저 퇴적물 용출액에서 적조발생 잠재력이 가장 높았고, 부산 형제도연안, 광양만, 거제만, 소리도연안의 해저퇴적물 순서로 적조생물의 성장을 촉진시키는 결과를 나타내었다. 그리고 적조생물의 성장은 인산염의 농도에 의해서 성장이 결정되었던 것으로 추정되며, 용출된 인산염의 농도 $1.59{\sim}10.39{\mu}M$ 범위로 남해 미조연안, 부산 형제도 연안, 광양만, 거제만, 소리도 연안 순서로 C. polykrikoides의 성장과 같은 순서로 나타났다.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 1996.10a
• /
• pp.102-108
• /
• 1996

연안매립 및 신항만 건설, 해안선 정비사업 등과 같은 대규모 공사는 인근 해역에서의 해수유동의 변화와 해수의 혼탁도 증가 및 퇴적물의 침식과 퇴적에 의한 해저 지형의 변형을 초래하고, 이로 인해 기존 항로의 매몰과 해양생물 생태계 변화 등과 같은 문제점을 유발한다는 것은 잘 알려진 사실이다. 특히 한국의 서해연안 대부분과 남해연안 일부에 분포되어 있는 미세-점착성 퇴적물은 사질성 퇴적물과는 달리 퇴적물에서 부유된 토사 입자의 침강 속도가 아주 작아서, 파랑과 조류 등과 같은 해수유동에서 의해 쉽게 이동되어 현저한 해저 지형의 변형을 초래한다. (중략)

• Journal of the Korean earth science society
• /
• v.24 no.4
• /
• pp.337-345
• /
• 2003

Surficial sediments from the northern coastal area of Jeju Island, southeastern Yellow Sea (South Sea of Korea) were analyzed for grain-size texture, some geochemical characteristics and clay mineralogy in order to assess their provenance. Rare-earth element compositions and some geochemical discrimination diagrams, especially of Ti/Al, Nb/Al and Rb/Al ratios, were revealed to be useful indices for identifying the origin of sediments. These indices, together with clay mineral compositions, suggest that the coarse-grained sediments originate from the volcanic rocks of Jeju Island, whereas the fine-grained sediments are derived from Chinese rivers, especially the Changjiang River. The oceanic circulation pattern and the physical-chemical properties of seawater in the Yellow and East China seal support the possibility that the fine-pained Changjiang (Yangtze River) sediments can reach the coastal area of Jeju Island (southeastern Yellow Sea).

• The Korean Journal of Quaternary Research
• /
• v.4 no.1
• /
• pp.15-26
• /
• 1990

Narrow (10-20 km wide) and steep (0.3-$2.4^{\circ}$) continental shelf off the eastern coast of Korea is covered with terrigenous clastic sediments reflecting the Holocene fluctuation of sea level. Surface sediments on the inner shelf consist of muddy sand and sandy mud with some gravels near the coast. However, sand or muddy sand, shell fragments and well rounded gravels occur near the edge of continental shelf at the depth of about 130-l50m. The coarse sediments near the shelf edge seem to be the relict or palimpsest sediments deposited under the nearshore environment during the low-stand or sea level due to so-called the Wisconsinan glaciation. Distribution of recent sediments near the coast and the inner shelf may reflect the affect of waves and currents precluding the deposition of fine sediment near the coast and on the shallow portion of shelf. Eastern Korean Warm Current also nay have played an important role to the transport and distribution of fine sediments from the south.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.2 no.1
• /
• pp.26-33
• /
• 1999

Coastal sediments in polluted areas adsorb many hydrophobic pollutants such as PCBs. During environmental remediation projects like dredging, they can be resuspended and transported to less polluted areas. To assess the environmental impact, the author previously developed a mathematical model that can simulate the changes of particle size distribution (PSD) due to sedimentation, vortical dispersion and coagulation. In this research, the simulation results using this model were presented in conjunction with observed PSDs from a 2-m settling column simulating coastal environments. The simulations showed that the model predictions were in fairly good agreement with the observed data (changes of PSDs in terms of depths and times), and that the resuspended sediments coagulated during the vertical transport. So, this study showed that the developed model has a good ability to describe the very complicated phenomena of real aggregation and vortical transport dynamics of coastal sediments with various particle sizes.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.1
• /
• pp.67-73
• /
• 2019

We carried out basic research to evaluate covering material for improving and managing contaminated benthic environments in coastal areas. Changes in nutrient concentration such as phosphate, hydrogen sulfide of contaminated sediment, and pH, Oxidation Reduction Potential (ORP) were investigated through mesocosm experiments for 6 months by covering contaminated sediment with granulated coal ash. Calcium oxide eluted from the granulated coal ash was confirmed to neutralize acidified sediment by increasing pH through hydrolysis. Also, calcium oxide and silica eluted from the granulated coal ash adsorbed and precipitated with phosphate in the sediment. The concentration of phosphate in the sediment investigated decreased by ca. 84.31 %. Similarly, the concentration of hydrogen sulfide decreased by 133.5 mg/L in one month. The hydrogen sulfide is considered to have reacted with substances such as manganese oxide which were eluted from the granulated coal ash and precipitated. Also, it was concluded that the hydrogen sulfide was reduced since anaerobic conditions in the sediment weakened. According to the results of these mesocosm experiments, granulated coal ash was found to be effective to remediate and manage benthic environments by covering the surface layer of sediment.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.15 no.1
• /
• pp.59-65
• /
• 2003

The changes of beach profile with a natural longshore bar and beach profile with a fixed artificial bar are studied, respectively, using a numerical model. The quasi three dimensional wave-current-sediment transport model is applied with an addition of boundary condition for sediment transport on the artificial structure under water. The study shows that the natural bar adapts itself to the change of coastal physical environment by adjusting its location but the fixed artificial bar causes the formation of a second natural bar seaward of the fixed bar and scouring at the rear of the fixed bar. This study can be applied to work on the change of beach profile with submerged breakwaters.

• Proceedings of KOSOMES biannual meeting
• /
• 2018.06a
• /
• pp.124-124
• /
• 2018

• Journal of Navigation and Port Research
• /
• v.29 no.6 s.102
• /
• pp.589-593
• /
• 2005

A laboratory study on the adsorption of nitrate in polluted coastal water using various materials including several types of dredged sediments(ST) and yellow c1ays(YC), which are activated by heat(HT), bioleaching for heavy metal removal(BL) and neutralization(NR) was performed. The equilibrium time of the adsorption for the sediment bioleached and treated by heat(BL-HT-ST) was only 17min which was faster than the sediment bioleached, neutralized and treated by heat(BL-NR-HT-S) (25min) or the sediment treated by the bioleaching process(BL -ST)(27min), but longer equilibrium times for yellow c1ay(YC) or heat treated yellow day(HT- YC) were required. The adsorption processes of nitrate in sea water for tested material could be described by Freundlich isotherm, but were significantly affected by surface characteristics of the materials. The adsorption capacities for raw sediment and heat treated sediment were 2.12 and 2.19mg NO3-N/g, respectively, which were higher than others, indicating that the sediment activated by heat could be used as a material for the improvement of nearshore water quality.