• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.212-212
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• 2021

지구온난화에 따른 가장 큰 영향 중의 하나인 해수면 상승은 인구 및 산업시설이 집중되어 있는 연안에 심각한 영향을 미칠 수 있다. 연안 저지대 범람, 하천과 지하수로의 해수 유입, 하천의 수위증가, 조석 및 퇴적물의 변화 등의 직접적 피해를 증가시키고(국립해양조사원, 2012; Nicholls, 2002; 오상명 등, 2011), 시설물의 설계고 추산 및 흐름, 파랑의 흐름에 영향을 미쳐 연안 시설물의 안정성이나 기능성에 영향을 미치는 것으로 알려지고 있다(윤종주·김상익, 2012). 기후변화에 관한 정부간 협의체(Intergovernmental Panel on Climate Change, IPCC)의 5차 보고서(2014)에 따르면, 1901~2010년 동안 전 지구 평균해수면 상승률은 1.7mm/year에 이르며, 1990년대 이후에 더 높은 해수면 상승률을 예측하였다. 우리나라의 경우, 2010년 말까지의 자료분석 결과에서 2.48mm/year의 연평균 해수면 상승률을 보여 전세계 평균상승률보다 훨씬 상회하는 것으로 보고되고 있다(정태성, 2014; 윤종주 등, 2012). 이와 같이 전 지구적 평균해수면의 변화와는 별개로 지역적 해수면 변동특성은 그 양상이 크게 다를 수 있으며, 이는 지구온난화와 같은 자연적인 요인 뿐만 아니라 지역별 다양한 인위적 요인(풍속, 기압, 연안역 개발정도 등)에 따라 지역적 해수면 상승이 크게 변화할 수 있다. 이에 본 연구에서는 국내 연안역에 분포한 조위관측소의 장기 관측자료(수위)를 이용하여 각 지역별 해수면의 상승경향을 분석하였으며, 동/서/남해안 및 제주권역은 권역별 조석특성이 현저하게 다른 특성을 보이므로 권열별로 구분하여 분석이 수행되었는데 우리나라 대부분의 관측지점에서 평균해수면이 증가하는 추세인 것으로 나타났다.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.5
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• pp.255-268
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• 2016

Climate change has increased the need to secure a new water resource in addition to the traditional water resources such as surface water and ground water. The seawater desalination market is growing sharply in accordance with this situation in Korea, "seawater engineering & architecture of high efficiency reverse osmosis (SEAHERO)" program was launched in 2007 to keep pace with world market trend. SEAHERO program was completed in 2014, contributed to turn the domestic technology in evaporative desalination technology to RO desalination technology. Currently, it is investigated that the average specific energy consumption of the whole RO plant is around $3.5kWh/m^3$. The Busan Gi-jang plant has shown $3.7{\sim}4.0kWh/m^3$, including operational electricity for plant and maintenance building. Although not world top level, domestic RO technology is considered to be able to compete in desalination market. Separately, many researchers in the world are developing new technologies for energy savings. Various processes, forward osmosis (FO), membrane distillation (MD) process are expected to compete with RO in the future market. In Korea, FO-RO hybrid process, MD and pressure retarded osmosis (PRO) process are under development through the research program in Ministry of Land, Infrastructure and Transport (MOLIT). The desalination technology level is expected to decrease to $2.5kWh/m^3$.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.4
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• pp.151-171
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• 2017

Most of oceanic current maps in the secondary school science and earth science textbooks have been made on the base of extensive in-situ measurements conducted by Japanese oceanographers during 1930s. According to up-to-date scientific knowledge on the currents in the Yellow Sea and the East China Sea (YES), such maps have significant errors and are likely to cause misconceptions to students, thus new schematic map of ocean currents is needed. The currents in the YES change seasonally due to relatively shallow water depths, complex terrain, winds, and tides. These factors make it difficult to construct a unified ocean current map of the YES. Sixteen major items, such as the flow of the Kuroshio Current into the East China Sea and its northward path, the origin of the Tsushima Warm Current and its path into the Korea Strait, the path of Taiwan Warm Current, the Jeju Warm Current, the runoff pattern of the Yangtze River flow, the routes of the northward Yellow Sea Warm Current, the Chinese Coastal Current, and the West Korea Coastal Current off the west coast of the Korean Peninsula, were selected to produce the schematic current map. Review of previous scientific researches, in-depth discussions through academic conferences, expert discussions, and consultations for three years since 2014 enabled us to produce the final ocean current maps for the YES after many revisions. Considering the complexity of the ocean currents, we made seven ocean current maps: two representative current patterns in summer and winter, seasonal current maps for upper layer and lower layer in summer and winter, and one representative surface current map. It is expected that the representative maps of the YES, connected to the current maps of the East Sea and the Northwest Pacific Ocean, would be widely utilized for diverse purposes in the secondary-school textbooks as well as high-level educational purposes and even for scientific scholarly experts.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.83-96
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• 2017

A constructed sea stream in Yeongdo, Busan, Republic of Korea is mostly static due to the lifted stream bed and tidal characters, and receives domestic wastewater nearby, causing a consistent odor production and water quality degradation. Bioaugmentation of a microbial consortium was proposed as an effective and economical restoration technology to restore the polluted stream. The microbial consortium activated on site was augmented on a periodic basis (7~10 days) into the most polluted site (Site 2) which was chosen considering the pollution level and tidal movement. Physicochemical parameters of water qualities were monitored including pH, temperature, DO, ORP, SS, COD, T-N, and T-P. COD and microbial community analyses of the sediments were also performed. A significant reduction in SS, COD, T-N, and COD (sediment) at Site 2 occurred showing their removal rates 51%, 58% and 27% and 35%, respectively, in 13 months while T-P increased by 47%. In most of the test sites, population densities of sulfate reducing bacterial (SRB) groups (Desulfobacteraceae_uc_s, Desulfobacterales_uc_s, Desulfuromonadaceae_uc_s, Desulfuromonas_g1_uc, and Desulfobacter postgatei) and Anaerolinaeles was observed to generally decrease after the bioaugmentation while those of Gamma-proteobacteria (NOR5-6B_s and NOR5-6A_s), Bacteroidales_uc_s, and Flavobacteriales_uc_s appeared to generally increase. Aerobic microbial communities (Flavobacteriaceae_uc_s) were dominant in St. 4 that showed the highest level of DO and least level of COD. These microbial communities could be used as an indicator organism to monitor the restoration process. The alpha diversity indices (OTUs, Chao1, and Shannon) of microbial communities generally decreased after the augmentation. Fast uniFrac analysis of all the samples of different sites and dates showed that there was a similarity in the microbial community structures regardless of samples as the augmentation advanced in comparison with before- and early bioaugmentation event, indicating occurrence of changing of the indigenous microbial community structures. It was concluded that the bioaugmentation could improve the polluted water quality and simultaneously change the microbial community structures via their niche changes. This in situ remediation technology will contribute to an eco-friendly and economically cleaning up of polluted streams of brine water and freshwater.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.496-505
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• 2020

In the previous research, the effectiveness of resonator was confirmed through the numerical analysis on two cases with the use of existing resonator at the Mukho and Imwon ports located in the eastern coast of South Korea by discussing the reduction rates of 1983 Central East Sea tsunami, and 1993 Hokkaido Southwest off tsunami, respectively. In this study, the reduction rates of tsunami height with three different resonators, Type I, II-1, and II-2, at the Samcheok port were examined respectively through the numerical analysis using COMCOT model under the same condition as the previous study. It was discussed the spatial distribution of maximum height of tsunami, change of water level, and effectiveness of resonator with the presence of new types of resonator, and change of their sizes. As a result, the effectiveness of resonator was verified through the application of new types of resonator reducing about maximum 40% of tsunami height. In order to design the optimal resonator for the variety of site condition, it is necessary to research about the various cases applying different shape, arrangement, and size of resonator as further study.

• 한국지구물리탐사학회:학술대회논문집
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• 2002.09a
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• pp.67-84
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• 2002

A shallow high-resolution seismic reflection survey was carried out at the Mineopo tidal flat on the western coast of Korea. The purpose of the survey was to investigate shallow sedimentary structure of the tidal (fat associated with the recent sea level change. A total of 795 shots were generated at 1 m interval from a 5-kg hammer source and recorded on 48 channels of 100 Hz geophones along two mutually perpendicular profiles. The water-saturated ground condition resulted in suppressed ground rolls by significantly decreasing rigidity. In addition, seismic velocities over 1500 m/s provided easy segregation of reflected arrivals from lower velocity noise. As a consequence, seismic sections were created that are high in resolution and signal to noise ratio as well. The stack sections show that the tidal flat consists of 5 sedimentary sequences above acoustic basement. Although deposition is largely characterized by the transgressive sedimentary facies resulting from sea level rise, erosional surfaces are well-resolved within the sequences.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.4
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• pp.295-304
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• 2012

This study proposed a two-dimensional horizontal numerical model based on the nonlinear shallow water wave equations to simulate tsunami propagation and coastal inundation. We numerically investigated the possible impacts of tsunami caused by the triple interlocked Tokai, Tonankai and Nankai Earthquakes on the Jeju coastal areas, using the proposed model. The simultaneous Tokai, Tonankai and Nankai Earthquakes were created a virtual tsunami model of an M9.0 earthquake. In numerical analysis, a grid nesting method for the local grid refinement in shallow coastal regions was employed to sufficiently reproduce the shoaling effects. The numerical model was carefully validated through comparisons with the data collected during the tsunami events by 2011 East Japan Earthquake and 1983 central East Sea Earthquake (Nihonkai Chubu Earthquake). Tsunami propagation triggered by the combined Tokai, Tonanakai and Nankai, Earthquakes was simulated for 10 hours to sufficiently consider the effects of tsunami in the coastal areas of Jeju Island. The numerical results revealed that water level fluctuation in tsunami propagation is greatly influenced by water-depth change, refraction, diffraction and reflection. In addition, the maximum tsunami height numerically estimated in the coastal areas of Jeju Island was about 1.6 m at Sagye port.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.277-281
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• 1997

The cell density changes of Vibrio mimicus K-1 in sea water and arkshell feeding it were examined at various temperature. The strain was suspended in sterilized sea water and storaged at experimental temperature $(5,\;10,\;15,\;20,\;and\;28^{\circ}C)$). At intervals of up to 10 days, aliquots of each suspension were plated onto BHI agar. At 5 and $10^{\circ}C$, the plate counts of V. mimicus K-1 showed a rapid decline, which 3s known to be a reault of this bacterium's entering into the viable but non culturable state. At 20 and $28^{\circ}C$, however, V. mimicus K-1 are stable over the 10 days experimental periods. V. mimicus K-1 was fed to arkshell, which was subsequently stored at temperatures ranging from 5 to $20^{\circ}C$ for 10 days. The samples of arkshell were homogenized and plated at intervals to determine the cell density of V. mimicus K-1 and total aerobic population of bacteria present. At 5 and $10^{\circ}C$, the numbers of V. mimicus K-1 in sea water rapid decreased over the 10 days experimental periods. However, little change of V. mimicus K-1 density was observed in shellstock arkshell at 5 and $10^{\circ}C$. While, V. mimicus K-1 density was decreased more rapidly to level below limit of dectection in shucked arkshell at same temperature. Incubation at the higher temperature $(20^{\circ}C)$ resulted in large increase in total aerobic bacterial number of shellstock arkshell. These results suggest that even with proper storage, indigenous levels of V. mimicus may remain sufficiently high in shellstock arkshell to produce infection in compromise hosts.

• Economic and Environmental Geology
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• v.42 no.6
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• pp.599-608
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• 2009

This study was conducted to examine chemical characteristics and correlations among seepage water, subsurface waters and inland groundwater in and around a coastal underground LPG cavern using factor and cluster analyses. The study area is located in western coast of Incheon metropolitan city and is about 8 km off the coast. The LPG cavern storing propane and butane was built beneath artificially reclaimed island. Mean bathymetry is 8.5 m and maximum sea level change is 10 m. Water sampling was conducted in May and August, 2006 from 22 sampling points. Correlation analysis showed strong correlations among $Fe^{2+}$ and $Mn^{2+}$ (r=0.83~0.99), and Na and Cl (r=0.70~0.97), which indicated reductive dissolution of iron and manganese bearing minerals and seawater ingression effect, respectively. According to factor analysis, Factors 1 (May) and I (August) showed high loadings for parameters representing seawater ingression into the cavern and effect of submarine groundwater discharge, respectively while Factors 2 and IV showed high loadings for those representing oxidation condition (DO and ORP). Factors 4 and II have large positive loadings for $Fe^{2+}$ and $Mn^{2+}$. The increase of $Fe^{2+}$ and $Mn^{2+}$ was related to decomposition of organic matter and subsequent their dissolution under reduced condition. Cluster analysis showed the resulting 6 groups for May and 5 groups for August, which mainly included groups of inland groundwater, cavern seepage water, sea water and subsurface water in the LPG storage cavern. Subsurface water (Group 2 and Group III) around the underground storage cavern showed high EC and major ions contents, which represents the seawater effect. Cavern seepage water (Group 5 and Group II) showed a reduced condition (low DO and negative ORP) and higher levels of $Fe^{2+}$ and $Mn^{2+}$.

• Korean Journal of Environment and Ecology
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• v.30 no.2
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• pp.155-164
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• 2016

In this study we analyzed the spatial and temporal distribution and preferred habitat type of the Kentish plover (Charadrius alexandrinus) based on the 3rd National Ecosystem Survey. Kentish plovers were observed in 97 maps out of a total 842 maps (11.8%) between 2006 and 2012, mainly along the western and southern coasts of Korea. They were also observed in the eastern coast of Korea, inland rivers (Han, Geum, Nakdong, Seomjin, and Yongsan River), the western and eastern coast of Jeju island, and Daecheong Island in the Yellow Sea. The observations were mainly made during the spring breeding season and migration seasons in spring and autumn. The occurrence of kentish plovers was positively influenced by the area of water and wetland according to the middle classification level of land cover type analysis and the area of coastal wetlands in the detailed classification level of land cover types. Most (90%) of the kentish plovers recorded maps had coastal wetlands. Kentish plovers were known to be susceptible to change of habitat. As the occurrence of kentish plovers could be associated with the habitat-change of coastal wetlands and it is possible to estimate the number of individuals, it is recommended that kentish plovers be used as a bioindicator species for the ecological assessment of ecosystem in intertidal zones.