• Title/Summary/Keyword: Estuary Weir

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Physical and Sedimentological Changes in the Keum Estuary after the Gate-Close of Keum River Weir (하구언 갑문폐쇄 후 금강하구의 물리, 퇴적학적 특성변화)

  • 최진용;최현용
    • 한국해양학회지
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    • v.30 no.4
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    • pp.262-270
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    • 1995
  • A comparative study to understand the changes in physical and sedimentological natures was carried out in the Keum Estuary before and after the gate-close of Keum River weir. After closing of weir-gate maximum tidal current speed decreased about 30∼40% compared with that of the previous gate-opening period. Water masses also represent vertical stratifications both on water salinity and water transparency. The Keum Estuary seems to be changed from the well-mixed type estuary during the gate-opening period to the "partially-mixed type" and/or "salt-wedge type" estuary after the closing of weir-gate. The concentrations of suspended matter range 10∼100 mg/l in surface waters after the gate-close of Keum River Weir, representing about 1/4 to 1/3 decrease than those during the gate-close of Keum River Weir, representing about 1/4 to 1/3 decrease than those during the gate0opening period. Such decrease of suspended mater appears to be due to the decrease in the resuspension of bottom sediments, and also due to the vertical stratification of water masses that prevented the upward diffusion of turbid bottom waters. It is, therefore, expected that the depositional environment of Keum Estuary has been changing into the low energy conditions after the closing of weir gate, resulting in the rapid deposition of fine suspended matters within the Keum Estuary.

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Characteristics of a Sea Area due to the Discharge through Yongam-Kumho Sea Dike (영암-금호방조제 방류에 의한 해역 특성)

  • 김강민;김상훈;유하상;정대득
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.04a
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    • pp.173-178
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    • 2004
  • Due to the development of Yongsan river estuary weir and Yongam-Kumho sea dike, Mokop coastal area is changed. Especially, Discharged water through Yongsan river estuary weir and Yongam-Kumho sea dike, may cause the environmental influences such as the changes of currents pattern and sedimentation in the vicinity of semi-closed Mokpo harbor. This study deals with the collection and analysis of discharge through estuary weir and sea dike, based on that, we analyzed a characteristics of a sea area from simulation. As the results of this study, it is known that discharge causes the changes of a tidal currents pattern and calculated depth variations showed close relation with tidal circulation.

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Study on Water Level and Salinity Characteristics of Nakdong River Estuary Area by Discharge Variations at Changnyeong-Haman Weir(1) (창녕·함안보 방류량에 따른 하류지역 및 하구역의 수리환경특성에 관한 연구(1))

  • Kim, Tae-Woo;Yang, Hyun-Soo;Park, Byeong-Woo;Yoon, Jong-Sung
    • Journal of Ocean Engineering and Technology
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    • v.32 no.5
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    • pp.361-366
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    • 2018
  • The present study analyzed the variation factors in inducing a salinity change using the existing observation network in the section between the Nakdong River Estuary Barrage and Changnyeong-Haman Weir, and also examined the seasonal changes in precipitation, salinity, and discharge. Furthermore, this study analyzed the causes of a salinity increase by collecting observational data during a period when abnormal salinity occurred, and further investigated the salinity transfer time in a section of approximately 5.3 km from the Nakdong River Estuary Barrage to Nakdong River Bridge to understand the behavioral characteristics of the salinity moving upstream. The study results would make it possible to control the increase in salinity and block salt water from moving upstream by understanding the salinity variation characteristics according to the discharge amount. This will provide stability in collecting water from various residential, agricultural, and industrial sources through water intake facilities scattered near the Nakdong River Estuary Barrage.

Analysis of Hydraulic Characteristics by Sediment Protection Weir on Natural River Estuary (자연하도 하구부의 방사보에 의한 수리학적특성 해석)

  • Ahn, Seung-Seop;Choi, Yun-Young
    • Journal of the Korean Society of Industry Convergence
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    • v.4 no.1
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    • pp.51-60
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    • 2001
  • This study examines the effects of removal of the sediment protection weir at Taehwa river mouth on hydraulic and around river environment considering the fact that the effects of the sediment protection weir which is installed to protect water level drop of Ulsan harbor caused by sediments according to flood in Taehwa river, Dong-chun, and so forth may add water quality contamination by flow stagnance in normal and drought period and accumulation of pollutants. The result is as follows. First, it is estimated from the examination of variation characteristics water depth and level for Taehwa river before and after removal of the sediment protection weir that about 0.01m of water depth down according to removal of the sediment protection weir occurs when low flow runs between the sediment protection weir which is located about 2.3km away from the estuary and Samho-gyo which is about 9.0km away from the sediment protection weir, and about 0.01~0.56m(directly upstream point of the sediment protection weir 0.56m, Myongchon-gyo 0.14m, Ulsan-gyo 0.03m, and Taehwa-gyo 0.02m) downs when design flood flows between the sediment protection weir and the upstream of Taehwa-gyo which is 10km away from the sediment protection weir. Therefore, it is thought that variation of hydraulic characteristics of water depth down and so on according to removal of the sediment protection weir is slight because water depth variation is only about 1cm between directly upstream point of the sediment protection weir and Samho-gyo. Next, it is estimated from the examination of variation characteristics of flow velocity for Taehwa river before and after removal of the sediment protection weir that about 0.0lm/s of flow velocity increase occurs between the directly upstream point of the sediment protection weir which is about 2.4km away from the estuary and the directly upstream point of Samho-gyo when low flow runs, and about 0.01~0.44m/s increases between the sediment protection weir and Samho-gyo when design flood flows. Therefore, riverbed erosion by the increased flow velocity is concerned but it is thought that the concern about riverbed erosion is not great because the mean velocity is about 0.07~1.36m/s when low flow runs, and about 1.02~2.41m/s when design flood flows for the sector which experiences the flow velocity variation.

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Hydraulic characteristics of a Sea Area due to the Discharge through Yongam-Kumho Sea Dike (영암-금호방조제 방류에 의한 해역의 수리적 특성)

  • Kim Kang-Min;Kim Sang-Hoon;Ryu Ha-Sang;Jeong Dae-Deuk
    • Journal of Navigation and Port Research
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    • v.28 no.10 s.96
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    • pp.925-931
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    • 2004
  • Due to the development of Yongsan river estuary weir and Yongam-Kumho sea dike, Mokop coastal area is changed. Especially, Discharged water through Yongsan river estuary weir and Yongam-Kumho sea dike, may muse the environmental influences such as the changes of currents pattern and sedimentation in the vicinity of semi-closed Mokpo harbor. This study deals with the collection and analysis of discharge through estuary weir and sea dike, based on that, we analyzed a characteristics of a sea area from simulation. As the results of this study, it was known that discharge mused the changes of a tidal currents pattern and calculated depth variations showed close relation with tidal circulation.

Flow Characteristics Induced by Shift and Modification of Submerged Weir at Han River Estuary (수중보 이설 및 변형에 따른 한강 하구 흐름 특성)

  • Baek, Kyong Oh;Yim, Dong Hee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.2B
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    • pp.109-119
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    • 2011
  • In this study, the flow characteristics of Han River Estuary were investigated by using a two-dimensional numerical model according to the assumption of shift and modification of the Shingok submerged weir. The two-dimensional analysis has contributed to our understanding of the hydraulic effects induced by shift of the weir on the topography, especially wetlands. The tide and flow discharge of 2007 were adopted as an input data for the simulation. The tidal data contained both spring and neap tide, and the flow discharge condition was divided into monsoon and normal seasons. The boundaries of this study were Hangang Bridge, Tongil Bridge, and Yu island. The simulation results showed that influence area of seawater changed depending on the weir shift, and the water level at particular station fluctuated according to the condition of tide and flow discharge.

Study on the Characteristics of Groundwater Movement Caused by Pumping During Drought Period and Estimation of Pumping Capacity in Natural River Estuary (자연하도 하구부에서 갈수시 양수에 의한 지하수 유독특성 및 취수능력 결정에 관한 연구)

  • 안승섭;최윤영
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.39 no.6
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    • pp.88-98
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    • 1997
  • In this study, pumping capacity in the area of natural river estuary is estimated by the quantitative analysis using finite element method. The study area is Iga-ri pumping station in the estuary of Seojung-chun which runs to the East coast. First of aH, hydraulic properties and effects of different seawater levels are analyzed in this area. Variations of groundwater level caused by pumping and properties of seawater intrusion are analyzed, then compared the case of reinforcing the existing intake weir with the case of setting up an weir at the upper stream. The observed data of groundwater drawdown caused by pumping during drought period and seawater intrusion are compared with results of the analysis done by groundwater model using finite element method, and it is found that both are similar. Accordingly, groundwater model used in this study reflects well the variation of groundwater level caused by pumping.

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A Study on the Change of Current in the Vicinity of Mokpo Harbor and Its Impact on Ship Operation due to the Discharge through Yongsan River Estuary Weir and Yongam-Kumho Sea Dike (영산강 하구둑 및 영암-금호방조제의 방류에 의한 목포항 주변수역의 유동변화 및 선박운용에 미치는 영향에 관한 연구)

  • 정대득;이중우;국승기
    • Journal of Korean Port Research
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    • v.13 no.1
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    • pp.133-146
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    • 1999
  • Mokpo coastal area is connected to the adjacent a long river and two large basins. It is essential for port planning coastal zone management and environmental impact study to analyze the data related to the ship operation and variation of current and water quality due to the development of water area including dredging reclamation and estuary barrage. The Yongsan river estuary weir and Yongam-Kumho basins discharge much of water through water gates for the purpose of flood control and prohibit salt intrusion at the inland fresh water area. To meet this purpose discharge through the gates have been done at the period of maximum water level difference between inner river and sea level. This discharged water may cause the changes of current pattern and other environmental influences in the vicinity and inner area of semi-closed Mokpo harbor. In this study ADI method is applied to the governing equation for the analysis of the changes on current pattern due to discharged water. As the results of this study it is known that the discharging operation causes many changes including the increase of current velocity at the front water area at piers approaching passage and anchorages. Discussion made on the point of problems such as restricted maneuverability and the safety of morred vessels at pier and anchorage. To minimize this influence the linked gate operation discharging warning system and laternative mooring system are recommended.

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Bed Changes downstream the Singok Submerged Weir in the Han River Estuary - from 2009 to 2010 (한강 하구 신곡수중보 하류에서 하상변동 - 2009년부터 2010년까지)

  • Hwang, Seung-Yong;Lee, Samhee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.38 no.6
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    • pp.819-829
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    • 2018
  • The bed change survey was carried out and its tendency was analyzed at the downstream of the Singok Submerged Weir in the Han River Estuary (HRE). In order to focus on the bed change in the low flow channel, we calculated the mean bed elevation based on the bankfull discharge. Thanks to the amount of bed changes calculated by using the 'averaged bed', we could compare the riverbeds of various periods with consistent criteria. In the HRE, revealed was the bed change cycle between degradation by flood and aggradation by tide at the non-flood season.