• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.125-125
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• 2023

Estuarine dams are dams constructed in estuaries for reasons such as securing freshwater resources, controlling water levels, and hydroelectric power generation. These estuarine dams alter the flow of freshwater to the coastal ocean and the tidal properties of the estuaries which has implications for the estuaries' circulation and sediment transport. A previous study has analyzed the effect of estuarine dams on 1D (along-channel) circulation and sediment transport. However, the effect of estuarine dams on the transverse variability of along-channel and across-channel circulation and sediment transport has not been studied and is not known. In this study, a coupled hydrodynamic-sediment dynamic numerical model (COAWST) was used to analyze the transverse variability of along-channel and across-channel flow and sediment transport in estuaries with estuarine dams. The estuarine dam was found to change the 3D structure of circulation and sediment transport, and the result was found to depend on the estuarine type (i.e., strongly stratified (SS) or well-mixed (WM) estuary). The SS estuary had inflow in the channel and outflow over the shoals, consistent with estuarine circulation. Longer discharge interval reduced the estuarine circulation. The WM estuary had inflow over the shoals and outflow in the channel, consistent with tide-induced circulation. As the estuarine dam was located nearer to the estuary mouth, the tide-induced circulation was reduced and replaced with estuarine circulation. The lateral circualtion was the greatest in the tide-dominated estuaries. It was reduced and changed direction due to differential advection change as the dam was located nearer the mouth. Overall, the WM estuary transverse flow structure changed the most. Lateral sediment flux was important in all estuaries, particularly for transporting sediments to the tidal flats.

• 한국해양공학회지
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• 제15권4호
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• pp.34-45
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• 2001

In the persent study, we conducted numerical experiments using a three-dimensional baroclinic equation model and a Lagrangian method for clarifying the hydrodynamics in Osaka Bay under the yearly mean discharge and visualizing the behaviour of particles of different settling velocity discharged from Yodo River and sedimentation pattern on the sea bottom. Particles are transported from the Yodo River to the south direction by the residual circulation of the bay head at the first stage, and after most of suspended solids particles are settled down at any layer and returned in the south-east coastal area through bottom layers by an estuarine circulation. The results show that estuarine circulation plays an important part of suspended solids transportation in the Osaka Bay.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.526-526
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• 2023

Water circulation plays a crucial role in regulating the salinity of estuaries, which is essential for the survival of estuarine organisms. Changes in freshwater inflows or sea level can have significant impacts on the distribution and abundance of species within these ecosystems. To better understand these dynamics, this paper presents a study of water circulation and salinity distribution in Seomjin River estuary using the Finite Volume Coastal Ocean Model (FVCOM) numerical model. An extreme scenario was simulated to assess the potential impact of tidal currents and river flow discharge on circulation and salinity distribution. The results of this study have important implications for managing estuarine ecosystems and conserving their associated biodiversity.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.313-317
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• 2005

This study aimed to estimate applicability of a model to simulate circulation in estuarine lake caused by operation of drainage gates. The model consists of 2D (depth-averaged) hydrodynamic models, Delft3D-FLOW model and operation model for drainage gates. The flow through drainage gates was calculated using weir formulae with discharge coefficient, 0.8. The simulations are performed under two conditions: uncontrolled condition and controlled by periods of two days. The results on simulation of the model showed that the water level in estuarine lake was tend to increase above mean sea level. Therefore it was proved that the calibration and verification were needed in order to applicate this model for Saemankeum area.

• 대한지리학회지
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• 제49권3호
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• pp.321-338
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• 2014

본 연구의 목적은 우리나라에 분포하는 463개 하구를 대상으로 하구습지의 권역별 분포특성과 시계열 변동추이를 하구순환 관점에서 파악하는 데 있다. 환경관리에 널리 이용되는 유역을 토대로 한강서해권역, 한강동해권역, 금강권역, 영산강권역, 섬진강권역, 낙동강권역, 제주권역을 대상으로 하구습지의 분포실태를 조사하고, 권역별 하구습지의 시계열 변동추이를 1980년대, 1990년대, 2000년대 토지피복지도를 확보하여 분석하였다. 분석결과, 한강서해권역, 금강권역, 영산강권역의 하구습지는 크게 감소한 것으로 나타났으며, 특히 하구둑, 배수갑문 등 인공구조물에 의해 하구순환이 차단된 닫힌하구에서의 습지감소폭이 크고, 하구순환이 유지되는 열린하구에서의 습지훼손은 상대적으로 적은 것으로 나타났다. 하구습지와 관련된 갯벌, 개방수면, 염습지, 암석해안, 모래해안 등 하구내 서식지 다양성은 하구순환이 차단된 닫힌하구에 비해 하구순환이 유지되는 열린하구에서 높게 나타났다. 본 연구에서 제시한 권역별 하구습지의 분포특성과 시계열 변동추이는 하구환경의 관리방향을 설정하거나 훼손된 하구습지의 복원전략을 마련하는 데 효과적으로 활용할 수 있다.

• 한국해양학회지:바다
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• 제29권2호
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• pp.77-100
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• 2024

진해·마산만에 대한 연구는 그동안 해수순환, 조석, 조류, 적조, 수질, 빈산소 환경을 주제로 많이 연구되었으나 주로 단기간 동안 일어나는 해양현상에 대해 연구가 수행되었으며, 만 전체적인 해수순환을 일으키는 물리적 기작을 자세히 살펴본 연구는 부족했다. 오염 물질의 이동과 확산 같은 현상은 주로 계절별로 변동성이 크기 때문에, 이 연구에서는 진해·마산만 해역의 해수순환이 계절적으로 어떻게 변동하는지를 파악하고자 하였다. 이를 위하여 3차원 해양 순환 모델을 이용하여 2016년부터 2018년까지 진해·마산만의 해수순환을 수치모의하고, 여름철과 겨울철 해수순환을 표층, 중층, 저층에 대하여 살펴보았다. 또한 조석, 바람, 담수 유입에 대한 민감도 실험을 수행하여 각 요인들이 해수 유동에 미치는 영향을 분석하였다. 진해·마산만의 해수순환은 가덕수도 저층에서 대한해협의 해수가 유입되고, 표층에서 진해·마산만의 해수가 유출되는 대류성 염하구 순환이 일어난다. 가덕수도를 통해 교환되는 해수의 순환은 크게 진해만 동부해역과 진해만 서부해역으로 나누어져 일어난다. 각 해역의 수로 방향을 기준으로 해수 수송량을 계산하였을 때, 진해만 동부해역의 남북방향 해수 교환 수송량은 진해만 서부해역에서 일어나는 동서방향 해수 교환량보다 겨울철에는 2.3배, 여름철에는 1.4배 크다. 진해만 서부해역은 계절별로 작용하는 힘들의 균형이 변화하여 해수순환 특성이 계절에 따라 크게 다르다. 겨울철에는 북서풍이 만드는 전단응력과 해수면 기울기의 영향으로 표층 해류가 남쪽으로, 저층 해류는 북쪽으로 흐르는 남북방향 대류성 순환이 강화된다. 반면, 남서풍이 부는 여름철에는 바람 응력에 의해 표층 해수가 동쪽으로 유출되고, 또한 남동쪽 해수면이 높아 북쪽 방향 순압성 압력경도력이 커져 동쪽 방향 유속이 강화된다. 저층에서는 밀도 구배가 커져 경압성 압력경도력이 남쪽으로 크게 작용하여 지형류 균형에 의해 가덕수도의 해수가 서쪽으로 강하게 유입하는 동서방향 대류성 순환이 겨울철보다 26% 강화된다. 진해만 서부의 대류성 순환은 겨울과 여름 모두 조류와 바람의 영향을 크게 받는다. 진해만 동부해역과 마산만에서는 모든 계절에 표층에서는 해수가 외해로 유출되고, 저층에서는 해수가 만 안쪽으로 유입되는 전형적인 염하구 순환을 보였다. 겨울철에는 바람과 담수유입이, 여름철에는 조류의 영향이 남북방향 염하구 순환 규모에 크게 기여하였다. 진해만 동부해역에는 지형의 영향을 받아 형성된 조석 잔차류도 뚜렷하다. 이 연구에서 제시한 진해·마산만의 계절별 해수순환 특성은 이 해역의 오염물질 확산, 여름철 빈산소수괴의 형성 기작 파악, 적조 생물의 유입과 유출을 이해하는 데 도움이 될 것으로 기대된다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.159-164
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• 2000

In order to clarify the seasonal variation of residual current and material transportation process in Hiroshima Bay, JAPAN, the real-time simulation of residual current and particle tracking by using Euler-Lagrange model were carried out. The calculated tidal current and water temperature and salinity showed good agreement with the observed ones. The residual currents showed the southward flow pattern at the upper layer, and the northward flow pattern at the lower layer. The flow structure of residual current in Hiroshima Bay is an estuarine circulation affected by density flow and wind driven current. The residual current plays an improtant role of material transportation in th bay.

• 한국해양공학회지
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• 제15권1호
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• pp.45-51
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• 2001

In order to clarify the seasonal variation of the residual current and the material transportation process in Hiroshima Bay, JAPAN, the real-time simulation of residual current and particle tracking by using the Euler-Lagrange model were carried out. The calculated tidal current, water temperature, and salinity showed good agreement with the observed ones. The residual currents showed a southward flow pattern at the upper layer, and a northward flow pattern at the lower layer. The flow structure of the residual current in Hiroshima Bay is an estuarine circulation affected by density flow and wind driven current. The residual current plays an important role of material transportation in the bay.

• 한국해양공학회지
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• 제21권2호
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• pp.22-34
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• 2007

We present basic data for developing new research topics and closely examine the existing data on the development and organization of the Nakdong River Estuary Delta by analyzing various studies of the area, including ocean engineering, coastal engineering, ocean environmental engineering, geomorphological, and geological studies. We first defined the general concepts related to the estuary and delta and reviewed the historical development of the Nakdong River Estuary Delta over the past 100 years. We then examined the origin and core elements of the estuary deposits that constitute the delta. In addition, we scrutinized the main factors affecting the development of the delta and analyzed existing research on delta development mechanisms by core researchers. The construction of an estuary barrage is one of the main factors effecting estuarine circulation and has altered the physical oceanic environment, area of deposition, atmospheric environment, and vegetation community of the delta. These factors affect the estuary circulation in turn, altering the delta. Along the Nakdong River, an unsteady-state sandy barrier appears at approximately three times the distance of the wavelength of incident offshore waves, and this terrain forms approximately 10-15 years after reclamation in the interdistributary upper stream and transforms the shoreline. It is necessary to develop a technique to predict terrain change that reproduces the erosion and accumulation of estuarine deposits. To determine the parameters and variables necessary to reproduce this system, continuous on-site monitoring is necessary. The existing research did not fully examine the terrain changes in Nakdong River Estuary or the periodic developmental characteristics. To understand the future process of estuary delta development, it is necessary to establish an integrated management system.

• 해양환경안전학회지
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• 제26권3호
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• pp.242-253
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• 2020

This study examined the ef ects of freshwater discharge by artificial dikes from the Kanwol and Bunam lakes on the dynamics in the Chunsu Bay, Yellow Sea, Korea, during the summer season based on three-dimensional numerical modeling experiments. Model performances were evaluated in terms of skill scores for tidal elevation, velocity, temperature, and salinity and these scores mostly exceeded 90 %. The variability in residual currents before and after the freshwater discharge was examined. The large amount of lake water discharge through artificial dikes may result in a dramatically changed density field in the Chunsu Bay, leading to an estuarine circulation system. The density-driven current formed as a result of the freshwater inflow through the artificial dikes (Kanwol/Bunam) caused a partial change in the tidal circulation and a change in the scale and location of paired residual eddies. The stratification formed by strengthened static stability following the freshwater discharge led to a dramatic increase in the Richardson number and lasted for a few weeks. The strong stratification suppressed the vertical flux and inhibited surface aerated water mixing with bottom water. This phenomenon would have direct and indirect impacts on the marine environment such as hypoxia/anoxia formation at the bottom.