• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.21 no.6
• /
• pp.453-461
• /
• 2009

Camera monitoring of topographical changes of intertidal flat was performed at Daehang-ri mud flat outside Semangeum sea dike No. 1, where creation of mud flat was reported after sea dike construction. Ground survey on the mud flat is often limited only to points or few line surveys because of difficulty of walking and limitation of working hours by flood/ebb. This study uses natures of tide that the water lines moving on the intertidal flat during a flood indicate depth contours between low and high tide. Ground coordinates for the water lines extracted from the consecutive images of intertidal flat are calculated and information of topography is acquired by integrating all the water line data. Analysis of 6 camera monitoring data between September 2005 and September 2009 shows 0.127 m deposition per year on the average and variation of deposition/erosion in space and time.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.16 no.1
• /
• pp.1-14
• /
• 2013

The world largest land reclamation project in the name of Saemangeum(Ariul) from 1991 to the present has been implementing in a part of the west coast of Korea. In the Saemangeum reclamation project, the large-scale project cost is used for the landfill reclamation. A number of landfill reclamation methods have been studied in order to reduce the large-scale cost of the Saemangeum project under construction. There are many studies related to the on-site real-time monitoring with mobile systems for operating a wide range of landfill. In order to apply the work method for efficient cost-savings in the landfill operations to the Samangeum project, this paper develops a mobile management system that is composed of a mobile interface module, a data server module for data transmission and storage, and an analysis server module to analyze the input data and derive the results. The mobile system is designed by analysing user's and system requirements, functional interactions, and data flow using unified modeling language(UML). The user interface is developed for the on-site real-time monitoring through the status and related attributes of land reclamation by using the digital maps of the Samangeum coverage via mobile devices. Finally, a mobile management system would be developed that can provide a 3D GIS service based on the Dry Internal Project Site Digging Reclamation Method(DIPSDRM).

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.22 no.4
• /
• pp.258-271
• /
• 2010

In order to figure out hydrodynamic and water quality changes after completion of dike construction of the Saemangeum, which behaves as a semi-enclosed estuarine lake, numerical simulations based on fine grid structure by using EFDC were intensively carried out. In this study some limitations of precedent study has been improved and gate operation were considered. Also 3 phases such as air-water-sediment interaction modeling was considered. It is clear that inner mixing of the Saemangeum is dominated by Mankyeong and Dongjin riverine discharges rather than the gate opening influence through the Lagrangian particle tracking simulations. Vertical DO structure after the dike completion shows steep gradient especially at Dongjin river estuary due to lessen of outer sea water exchange. Increasing SOD at stagnantly changed man-made reservoir might cause oxygen deficiency and accelerating degradation of water quality. According to TSI evaluation test representing eutrophication status, it shows high possibility of eutrophication along Mankyeong waterway in spite of dike completion, while the index is getting high after final closing along Dongjin waterway. Numerical tests with gate operations show significant differences in water quality. Thus it should be noted that proper gate operation plays a major role in preserving target water quality and management for inner development plan.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.18 no.2
• /
• pp.51-63
• /
• 2015

In order to investigation long-term variations of water qualities in the Saemangeum Salt-Water Lake formed after the sea-dike construction, the survey has carried out over 40 time from 2002 to 2010. The decreased salinity in surface water immediately after the dike construction has maintained on equal terms for years. After the dike construction, the early concentration of SPM in surface water has decreased but then it showed the tendency to move up and down due to the changes of water level in the lake. The elevated concentration of Chl-a in surface water initially after the dike construction was kept at the same conditions for years. The concentration of DIN in surface water has not changed before and shortly after the dike construction. However, the concentration of $NH_4-N$ in surface water has increased steadily after the dike construction. Consequently the concentration of DIN in the lake water after years has raised compared to pre-dike construction. The reduced concentration of DIP in surface water soon after the dike construction has increased after years as well as $NH_4-N$ due to the accumulation of organic matter to inside lake. Unlike with the unvaried $NO_3-N$, the concentration of DISi in surface water after the dike construction has immediately increased and maintained the enhanced level indicating the supply from other sources except the freshwater. Since the dike construction, the spatial characteristics of water quality was divided river sides and rest of the lake markedly. Stratification of river sides was more strong than the dike sides. In the warm seasons, hypoxia causing the release of nutrients and metals from sediment was observed downward about 1 m from surface of river sides. We strongly suggest to make some urgent measure to prevent low dissolved oxygen condition in the bottom layer of the river sides.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.17 no.4
• /
• pp.306-317
• /
• 2014

This study has been executed to understand the additional and removal processes of nutrients in the Saemangeum Salt-water Lake, and discussed with other monthly-collected environmental parameters such as water temperature, salinity, dissolved oxygen, suspended solids, and Chl-a from 2008 to 2010. $NO_3$-N, TP, $PO_4$-P, and DISi showed the removal processes along with the salinity gradients at the surface water of the lake, whereas $NO_2$-N, $NH_4$-N, and Chl-a showed addition trend. In the bottom water all water quality parameters except $NO_3$-N appeared addition processes indicating evidence of continuous nutrients suppliance into the bottom layer. The mixing modelling approach revealed that the biogeochemical processes in the lake consume $NO_3$-N and consequently added $NH_4$-N and $PO_4$-P to the bottom water during the summer seasons. The $NH_4$-N and $PO_4$-P appeared strong increase at the bottom water of the river-side of the lake and strong concentration gradient difference of dissolved oxygen also appeared in the same time. DISi exhibited continuous seasonal supply from spring to summer. Internal addition of $NH_4$-N and $PO_4$-P in the river-side of the lake were much higher than the dike-side, while the increase of DISi showed similar level both the dike and river sides. The temporal distribution of benthic flux for DISi indicates that addition of nutrients in the bottom water was strongly affected by other sources, for example, submarine ground-water discharge (SGD) through bottom sediment.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.6
• /
• pp.587-597
• /
• 2023

We evaluated the eutrophication of Saemangeum Lake, which causes abnormal growth of algae, using the Carlson index. Eutrophication characteristics of Saemangeum Lake were analyzed. For the study, water quality surveys were conducted at 7 stations in Saemangeum Lake every month in 2021. The concentration of Chl.a was slightly higher in the Mankyeong water system in winter, and slightly higher in the Dongjin water system in spring and summer, but overall, except for some periods, the concentration was similar to or lower than the lake water quality environmental standard of class 3. COD showed water quality similar to or above the lake quality environmental standard of grade 4 in both the Mankyeong and Dongjin water systems in the summer and Autumn. TOC concentrations were within lake water quality standard 3 at all sites. Total phosphorus concentrations exceeded the lake water quality standard of Class 4 and were higher in January and August after rainfall. In the correlation analysis between water quality factors, the correlation of organic matter, total phosphorus, and total nitrogen to salinity was relatively high. This reflected the water quality characteristics of freshwater, brackish water, and seawater areas due to seawater inflow through the drainage gate and freshwater inflow through upstream rivers. According to the characteristics of eutrophication fluctuations in Saemangeum Lake by trophic state index, the indices of Chl.a, SD, and TN showed water quality in the early stage of eutrophication, while the TP index showed a severe eutrophication state. The magnitude of the eutrophication index among water quality components was TSI(TP) > TSI(TN) > TSI(SD) > TSI(CHL) in all water systems. Quadrant analysis of the deviation of TSI(CHL) from TSI(TP) and TSI(SD) on a two-dimensional plane showed that there was no limiting effect of total phosphorus on algal growth in all water systems. In addition, the factors af ecting light attenuation appeared to be dominated by small particulate matter from outside sources.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2018.05a
• /
• pp.422-422
• /
• 2018

우리나라의 간척사업은 고려시대 중엽부터 서남해안에 다수 산재되어 있는 천혜적인 간척 적지를 대상으로 지속적으로 추진되어 국토확장 및 식량 자급달성에 기여하여 왔다. 그러나, 최근 들어 쌀 수급 등 농업정책의 변화, 비용에 대한 경제성 평가의 변화, 개발과 보전에 관한 이해당사자간의 대립 등으로 신규 간척사업의 추진이 어려워지고 기존 간척지의 토지이용 목적 변화와 이치수 기능개선을 목적으로 배수갑문을 확장하는 등의 사업이 추진되고 있다. 본 연구에서는 방조제 상류지역 및 지천에서 이상홍수 유입에 따른 방조제 안정성 검토를 실시하였다. 호내로 유입되는 빈도별 홍수량에 따른 각 지점별 수위변화를 이용하여 방조제 비상대처계획에 대한 재난관리 지표로 활용할 수 있는지를 확인한다. 이를 위해 선정된 방조제를 중심으로 빈도별 홍수량을 산정하여 수문학적 안정성을 검토하고, 빈도별 홍수량에 따른 호내의 홍수위 변화를 통하여 비상대처계획 시나리오를 구성하고자 한다. 새만금 유역의 수치모델링에 필요한 범위를 설정하고, 모델 구성 및 자료를 입력한 후 검 보정을 통하여 모델의 신뢰성을 검증한 후 모델운영 조건을 설정하였다. 새만금 종합개발계획(MP)이 완료되었을 경우를 가정하여 통합운영을 실시하였다. 호내 관리수위에 따른 100, 200, 500, PMF 홍수량 유입시에 호내 홍수위 모의를 수행하였다. 또한, 비상단계 중 초기단계인 '관심단계'를 "이상홍수 발생부터 관리수위 EL-1.5m까지"로 설정한다면 방조제 초기 재난대응이 유리해 질 것으로 판단된다. 또한, '주의단계'는 "관리수위 EL-1.5m부터 호내 관리홍수위 EL+1.5m까지"로 '경계단계'를 "호내 관리홍수위 EL+1.5m부터 제당 내측사석보호공 홍수위까지", '심각단계'를 "제당 내측사석보호공(만경유역 EL+4.5m, 동진유역 EL+2.5m) 이상의 홍수위"로 설정한다면 방조제 관리자에게 세부화된 정보 및 지표를 제공해 줄 것이라 판단된다. 방조제 비상상황 단계별 분류에서 이상홍수위 발생후의 시간을 수치모의를 통해 구분하였으며 정성적인 위기상황 판단이 아닌 구체적인 수치로 된 지표들을 방조제 위기상황 재난지표로 활용한다면 상황 관리자의 위기상황 판단과 대처를 위한 의사결정에 도움이 될 것으로 기대한다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.669-673
• /
• 2005

신태인 수위관측소는 동진강 본류에 위치하고 있으며 이 지점의 유역면적은 $218.0km^2$이고 하구로부터 19.0km 떨어져 있다. 이 지점은 하류에 위치한 동진제수문의 영향을 받는 곳에 설치된 수위관측소이다. 신태인 수위관측소에서 하류로 약 9km 지점에 부량 수위관측소가 있으며 이 지점에서 약 300m 하류에 동진제수문이 설치되어 운영되고 있다. 이 수위관측소는 하류의 동진제수문의 영향을 받고 있는 상황에서 수위-유량곡선이 개발되어 운영되고 있으며 수위-유량곡선은 저류와 방류로 구분되어 있다. 이들 관측소가 속해 있는 동진강에서 유출되는 유량은 새만금 간척사업지구내의 새만금호로 유입되기 때문에 중요하다. 신태인 수위관측소 지점의 유량측정은 1997년부터 2003년까지 실시되었다. 1999년부터 이 지점의 수위-유량곡선을 동진제수문의 개폐여부에 따라서 저류와 방류로 구분하여 수위-유량곡선을 제시하였다. 이 때 수문의 개폐여부는 동진제수문의 관리 대장을 참조하여 단순하게 구분하였다. 개방여부의 정도가 상류의 신태인 수위관측소에 영향을 미치기 때문에 이를 반영된 수위-유량곡선의 개발이 쉽지 않으며 실제 신태인 수위관측소에 관측된 수위에 따른 유량의 분포가 산포되어 있는 상황이다. 특히 평수위 이하에서 더 심한 것으로 나타났다. 이런 상황에서 단일 수위-유량곡선을 개발하여 적용하는 경우에 오차가 심한 것으로 나타나 있으며 실제 상황에서 저류와 방류로 구분하여 개발된 수위-유량곡선을 적용하는데 한계가 있다. 이를 극복하기 위해 동진제수문의 상류 약 300m 지점에 부량 수위관측소가 설치되어 있는데 이 지점의 수위관측소의 수위를 고려하여 부량 지점 수위와 신태인 지점 수위와 유량의 상관성을 분석하였다. 그리고 신태인 지점의 수위-유량곡선을 저류와 방류로 구분한 경우와 통합한 경우의 수위-유량곡선식을 비교하였다. 이 지점은 하류 수문의 영향을 받기 때문에 하류의 조위 등으로 영향을 받는 경우에 종종 사용되는 지수형 다중 회귀식을 적용하여 수위-유량곡선을 제시 하였으며 그 결과를 실측값과 비교한 결과, 상관계수가 양호하게 평가되었다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.1
• /
• pp.895-899
• /
• 2015

The present study examined the phytoplankton communities of 4 regions, fresh water sites, estuary, Mankyeong and Dongjin lake and offshore regions, 4 times a year from 2011 to 2013. The number of species were 48-59 in 2011 (March, June, September, and November). From Mankyeong and Dongjin lake, fresh water species were dominated in June and coexisted with seawater species in September 2011. 45-65 species were observed in 2012 (April, June, September, and November) and diverse cyanophytes were present at the fresh water sites in September. The number of species reached up to 56-69 in 2013 (March, June, September, and November). In particular, owing to the diverse dinoflagellates from seawater and various cyanophytes and chlorophytes from fresh water, the maximum species number was recorded in June, 2013.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2006.09a
• /
• pp.29-32
• /
• 2006