• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.557-561
• /
• 2006

매년 영산강 본류 수질이 악화되고 있는 영산강 유역주변은 최근 전남도청 이전에 따른 남악 신도시개발, J-Project 및 환경 문화 복원사업의 추진, 기업도시개발등과 관련하여 수질관리개선 및 주요환경현안으로 대두되고 있다. 따라서 영산강 하구역 관리방안 중 담수호 수질개선대책의 일환으로 수문개방을 통한 해수 유입에 의한 수질 개선을 효과를 도모하는 방안이 제시되고 있다. 이에 하구호 방조제의 수문 개통 및 완전 개방에 따른 수질개선 문제에 앞서 발생할 수 있는 환경변화 중 영산강 및 연안역 염분의 확산범위를 평가하기 위하여 수치모형 실험이 실시되었다. 담수 유입에 따른 염분 확산 범위 및 해수 유입에 따른 염분의 역상 범위를 평가 하기위해 수치 모델로는 EFDC를 적용하였고, 하천형상과 연안역을 동시에 고려하기 위해 수평좌표계는 직교곡선좌표로 격자 크기는 $120{\sim}1000m$, 연직방향으로 시그마좌표를 사용하였다. 담수 방류 및 염분역상 효과를 알아보기 위해 1997년부터 2005년까지의 하구 수문 방류량 및 하천 유입량으로부터 홍수기와 갈수기를 선택하여 현재 상황 및 수문의 부분 개통 하구둑 완전 개방에 시나리오를 설정하여 실시하였다. 수문의 부분개통과 하구둑 완전 개방에 따른 염분 확산 범위는 영산강 하구둑을 기준으로 홍수기에는 $13{\sim}17km$, 갈수기에는 36km 이상의 상류지역에서 해수와 담수의 분리 기준인 0.3 psu 범위가 계산됨을 알 수 있다.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.12 no.3
• /
• pp.188-196
• /
• 2009

This study conducted numerical simulations to analyze the wave characteristics(distribution) depending on the directional changes of waves in the Nakdong river estuary by using SWAN(Simulating WAves Nearshore) model. The results from the tests are summarized as below. The wave height rates are generally highly distributed with the incident waves from the S, SSE, SSW, SE, SW in sequence. When the waves from the S, SSW, SSE directions are predominant, the bigger waves were observed in front of sandbars. According to the results of the wave steepness against the wave direction, at the east coast of Gadeok island(northwest of Nakdong estuary), where has mild seabed slopes, the wave height rates distribute in the range of 0.4~0.6; the wave height rates over the west coastal region of Dadeapo(southeast of Nakdong estuary) are 0.5~0.6. The wave height rate tends to be rapidly decreased over the east region of Nakdong river estuary rather than its west region.

• Journal of the Korean GEO-environmental Society
• /
• v.22 no.3
• /
• pp.15-29
• /
• 2021

The purpose of this study is to establish an ecosystem model that can predict ecosystem fluctuations in the Nakdong estuary, and use this model to calculate total primary production and respiration. AQUATOX model was used as the ecosystem model, and the model was calibrated and verified using the measured data. For the calibration of the model, chlorophyll-a data measured at the Nakdong estuary were used, and the model verification was performed using DO, TN, and TP data. In general, the total primary production and respiration volume vary greatly depending on the season, but the total primary production and respiration in the Nakdong estuary were greatly influenced by the amount of water discharged from Nakdong estuary bank. When the amount of effluent increased, photosynthesis could not be performed due to the loss of phytoplankton living in the lower area, and the total primary production amounted to zero, whereas the respiration increased sharply due to the inflow of organic substances contained in the effluent. The increase in the inflow water means the inflow of organic substances contained in the inflow water, and the organic substances are decomposed by oxidation, reducing dissolved oxygen. Compared with other countries' estuaries, the Nakdong estuary shows the lowest total primary production and because the respiration is larger than the total primary production, the dissolved oxygen is depleted by the oxidation of organic matter.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.28 no.4
• /
• pp.158-177
• /
• 2023

An estuary is a transitional water area that links the land and sea through rivers and streams, transporting various components from the land to the sea, which plays an important role in determining primary productivity in the coastal environment, and this coastal ecosystem captures a huge amount of carbon into biomass, known as blue carbon, which mitigates climate change as a potential carbon reservoir. This study examined the variation of mean grain size and organic carbon content of the surface sediments for 6 years and analyzed their relationship in the western and southern estuarine areas (Han River Estuary, Geum River Estuary, Yeongsan River Estuary, Seomjin River Estuary, and Nakdong River Estuary) and the East Sea upwelling area. During the sampling period (2015 to 2020), seasonal variation of both properties was not observed, because their variations might be controlled by diverse oceanographic environments and hydrographic conditions within each survey area. However, despite the synoptic problem of all samples, the positive relationship was obtained between the averages of mean grain size and organic carbon content, which clearly distinguishes each survey area. The unique positive relationship in all estuarine areas implies that the same process by sediment clay particles is important in the organic carbon accumulation. However, additional important factor may be expected in the organic carbon accumulation in the East Sea upwelling area. Further necessary data (sedimentation rate, dry bulk density etc) should be required for the estimation of carbon stock to evaluate the major estuaries in Korea as potential carbon reservoirs in the coastal environment.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.26 no.3
• /
• pp.184-195
• /
• 2014

After building the dyke in Nakdong River Estuary, mixing of freshwater inflow to ocean and seawater to upstream is controlled by operating the sluice gates. Mixing and convergence of seawater and freshwater by opening the sluice gates, have a major impact on the circulation of seawater in the Nakdong River Estuary. Field measurement was carried out to study the characteristics of the estuary flow and environment of each channel of the Nakdong River Estuary. Vertical salinity distribution and residual current is different from each channel by the river discharge and topographic changes.

• Journal of the Korean association of regional geographers
• /
• v.17 no.5
• /
• pp.521-535
• /
• 2011

This study intended to explain the relationship between climate change and magnetic susceptibility of estuarine sediment. Data of OSL dating and magnetic susceptibility from estuarine tidal sediment were compared with various climate change data. During the last Holocene, the intense of magnetic susceptibility related with weaker Siberian High and stronger Asian Summer Monsoon. It is explained that high precipitation and runoff made much fluvial sediment input to the estuary. From the early to mid Holocene, there is no clear relationship between climate change and MS because of the much coastal sediment input caused by rapid sea level rise and the formation of upland soil and coastal marsh. These results contribute to reconstruct paleo-environmental changes of west coast of Korea, in the way of using benefit of ubiquitous estuarine tidal flats and relatively useful magnetic susceptibility methodoloy.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.17 no.3
• /
• pp.185-189
• /
• 2011

To predict the deposition characteristic in the Nakdong river estuary, the material budget of Suspended Solid(SS) was investigated with the amount of Nakdong river discharge being set as dry season and flood season. The results of material budged of SS in dry season and flood season were 60,708 kg/day(inflow) and 306,892 kg/day(outflow), respectively.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2006.11a
• /
• pp.445-448
• /
• 2006

본 연구는 기초적인 연구로 낙동강 하구역을 단순 사각형 만의 형상을 가진 지형으로 설정하고 내부 지형의 변화(수심 및 사주 면적)에 따른 해수유동장을 해수유동 수심적분모델로 구축하여 계산하였다. 계산된 유속장 결과를 바탕으로 내부 지형의 대표단면에서의 단면유량플럭스를 계산하여 상호 비교함으로써 하구역내 사주의 생성 및 발달(내부 지형 용적 변화)에 따른 하구역 입구부에서의 해수용적 변화(순환)의 정도를 평가하고자 하였다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.982-985
• /
• 2010

섬진강 하구는 남해안 중부에 위치해 있으며, 하구둑이 건조되어 있지 않아 하구역 일대와 광양만이 하나의 넓은 기수역을 형성하고 있다. 또한 섬진강 하구는 상류에 섬진강댐, 주암댐 등이 건설되고 취수량이 증가하면서 하구로 유입되는 수량이 감소해 기수역이 상류로 확대된 것으로 보고되고 있다. 2008년 주암댐에서는 갈수기 때마다 대두되는 수질악화 및 염수침입을 방지하고자 3/10~3/24일에 걸쳐 1차, 4/23~5/7에 걸쳐 2차로 나누어 flushing 방류를 실시하였다. 이에 본 연구에서는 실측된 염분 자료를 토대로 3차원 수리 및 수질해석이 가능한 EFDC 모형을 활용하여 flushing 방류를 실시한 경우와 하지 않았을 경우에 대하여 모의를 수행함으로써 flushing 방류 유무에 따른 하구의 염수침입 및 염해피해 방지 효과에 대해 분석하였다.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 1992.08a
• /
• pp.188-191
• /
• 1992

최근 해양공간의 이용 및 개발과 관련해서 하구역이나 연안해역의 개발이 활발하게 진행됨에 따라 연안해양환경의 예측과 제어에 관한 기술 개발이 중요한 과제로 대두되고 있다. 하구역이나 연안해역에 분포하는 물질 가운데 상당부분이 점토나 실트와 같은 점착성토사와 유기성 현탁입자로 구성되어 있다.(중략)