• Title/Summary/Keyword: Tributary

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The Change of Flow depending upon the Discharge and Approaching Angle at Channel Junctions (합류부의 유량 및 접근각도에 따른 흐름변화)

  • Choi, Gye-Woon;Park, Young-Suop;Han, Man-Shin
    • Journal of Korea Water Resources Association
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    • v.37 no.8
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    • pp.623-630
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    • 2004
  • In this paper, the hydraulic model tests are conducted for the hydraulic characteristics at channel junctions. The experiments are examined through the variation of approaching angle, discharge in the upstream main channel and the discharge ratio between the main channel and the tributary. The experiments are conducted in the channel model having the length of 450cm, the widths of 40cm and 32cm. Four water tanks and pumps are installed in the experimental channel. The length of stagnation zone is increased by Increasing of approaching angle and the discharge in the upstream channel. The length of stagnation increase with the discharge ratio between the main channel and the tributary. However, the variation of the stagnation zone near the channel junctions is little at the same approaching angles and the discharge ratioes between the main channel and tributary. However, the variation of the stagnation zone near the channel junctions is little at the same approaching angles and the discharge ratioes between the main channel and tributary. Accelerating zone of the velocity is occurred in the middle of the channel in the small approaching angle. However, the influence zone of the accelerating velocity is increased by increasing the approaching angle.

Analysis of the Effect of Dredging and Weirs on Bed Change in the Nakdong River and its Tributary using HEC-6 (HEC-6를 이용한 준설 및 보로 인한 낙동강 본류 및 지류 하상변화 분석)

  • Ahn, Jung Min;Kwak, Sunghyun;Lyu, Siwan
    • Journal of Korea Water Resources Association
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    • v.48 no.9
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    • pp.743-756
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    • 2015
  • It is necessary to evaluate the effect of dredging and weir operation on the flow and long-term bed change for river management. Especially, large scale river treatment project, with dredging or weir installation and operation, can increase the instability of riverbed in tributaries as well as mainstream. This study focuses on the effect of weir installation and dredging on the long-term bed change in Nakdong river (Gangjeong- Goryeong Weir~Dalseong Weir) and its tributary (Geumho river). HEC-6 model has been used to analyze the amount of long-term bed change and sediment transport resulted from the river treatment including dredging or weir installation. From the result, it was concluded that a large scale river treatment can accelerate and increase the long-term bed change both in mainstream and tributary.

The Relationship between Algae Transport and Current in the Daecheong Reservoir (대청호 유속에 따른 조류이동 영향)

  • Yu, Soon-Ju;Hwang, Jong-Yeon;Chae, Min-Hi;Kim, Sang-Yong
    • Journal of Korean Society on Water Environment
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    • v.22 no.5
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    • pp.887-894
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    • 2006
  • Water quality in the Daecheong reservoir has been deteriorated by algal bloom every year. Algal bloom is propagated from eutrophicated tributary into the main body of the reservoir during the wet season. Nutrients from diffuse sources trigger the propagation of the algal bloom. This study is aimed to analyze relationship between the water current by the simulation and algae transport from the main body in the Daecheong reservoir including tributary where algal bloom has occurred seriously every year. Water quality model CE-QUAL-W2 was applied to analyze water movement in draught season (2001) and flooding season (2003). The result of simulation corresponded with the observed water elevation level, 63~80 m and showed stratification of the Daecheong reservoir. In the draught season, as velocity and direction off low in the reservoir was estimated to affect algae transport including nutrient supply from small tributary, algal blooms occurred in the stagnate zone of middle stream of the reservoir. On the other hand, in the flooding season, it was resulted in nutrient transport from upstream of main reservoir and nutrients were delivered up to downstream by fast water velocity. In result, algal blooms occurred in stagnate zone of reservoir downstream as the current of downstream was retarded according to dam outflow control.

Junction Flow Analyses by Twp-Dimensional Numerical Model (2차원 수치모형에 의한 합류흐름 해석)

  • Yoon, Tae-Hoon;Jung, Eui-Taek;Park, Jong-Suk
    • Journal of Korea Water Resources Association
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    • v.31 no.5
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    • pp.529-538
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    • 1998
  • The flow configurations at open channel junctions are analyzed by 2-D depth averaged mathematical model. The governing factors of the flow at the junction are found to be discharge ratio between tributary flow and the post confluence combined flow, and confluence angle. Analyzed by these two factors are flow patterns and flow depth variation at the confluence, discharge ratio above which the flow upstresm from the junction is affected by the tributary flow and the geometries of a recirculation region. Further, the flow contraction in the downstream region and the deflection of the tributary flow in the main channel were investigated. The numerical results are compared with the existing experimental data fairly well.

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The Analysis of Hydraulic Characteristics at Channel Junctions through Hydraulic Model Tests (수리모형실험을 통한 합류부에서의 수리학적 특성분석)

  • Choi, Gye-Woon;Park, Young-Suop;Han, Man-Shin;Kim, Young-Gyu
    • Journal of Korea Water Resources Association
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    • v.37 no.10
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    • pp.881-888
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    • 2004
  • In this study, the hydraulic characteristics at junction are studied through the variation of approaching angle, discharge in the upstream channel and the discharge ratio between the main channel and the tributary. The maximum velocity as well as the position of the maximum velocity is included in the hydraulic characteristics. The maximum velocity is increased by increasing of approaching angle, discharge in the upstream channel and the discharge ratio between the main channel and the tributary. The length from the channel junction to the point of maximum velocity is increasing by increasing of approaching angle, discharge in the upstream channel and the discharge ratio between the main channel and the tributary.

Acquisition of Evidential Information to Control Total Volume of Road Density per Tributary Watershed (도로밀도에 대한 소하천 유역 기반의 총량규제 기초자료 확보 방안)

  • Um, Jung-Sup
    • Journal of Environmental Impact Assessment
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    • v.14 no.5
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    • pp.317-335
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    • 2005
  • This paper is primarily intended to propose a new concept of "aggregate control of road density" which is defined as the area-wide road surface per watershed area. An empirical study for experimental sites was conducted to confirm how a standard GIS technology can be used to assist in estimating the road density in terms of total volume threshold control. Guidelines for a replicable methodology are presented to provide a strong theoretical basis for the standardization of factors involved in the estimation of the road space threshold; the meaningful classification of road types, delination of watershed boundary, interpretation for distribution trends of road density etc. A variety of visual maps using overlay analysis can be generated over large areas quickly and easily to show the fact that some degree of road space already exists in the experimental sites. They could be used as an evidence to limit further construction of road network in comparison with other tributary watershed. It is anticipated that this research output could be used as a valuable reference to confirm the potential of introducing the new concept of "site specific road density" to support more scientific and objective decision-making in the process of road construction project.

The Responses of a Small Lake Watershed to an Inorganic Carbon Cycle (무기탄소 순환에 대한 소규모 호수 유역의 반응)

  • Cho, Youngil
    • Journal of Korean Society on Water Environment
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    • v.29 no.5
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    • pp.610-617
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    • 2013
  • Investigating the budgets of alkalinity and dissolved inorganic carbon (DIC) in lake water systems is significant for the examination of the behavior of a lake as a sink or a source with respect to the circulation of inorganic carbon chemistry. Budgets of total alkalinity ($Alk_T$) and DIC in Onondaga Lake, which was polluted by chronic calcium (Ca) loading in spite of the closure of soda ash ($Na_2CO_3$) facility, were determined by the analyses of inorganic carbon chemistry in tributary stream channels linked to the lake. AlkT and DIC fluxes of Onondaga Creek and Ninemile Creek occupied 65% and 54%, respectively, as larger tributary streams in comparison with other tributaries as well as different input sources. Budget calculations indicate that 18% of AlkT and 11% of DIC inputs to Onondaga Lake, respectively, remained immobilized in the Lake. This suggests that Ca chronically leached had been precipitated with inorganic carbon or remineralized by secondary mineral formation during the experimental period. In this study, the assumed mass balance calculation in Onondaga Lake with tributary streams resulted in exhibiting that the lake played a role of the sink for the inorganic carbon cycle.

Flow Rate·Water Quality Characteristics of Tributaries and a Grouping Method for Tributary Management in Nakdong River (낙동강 지류·지천의 유량·수질 특성 및 하천관리를 위한 등급화 방안 연구)

  • Na, Seungmin;Lim, Tae Hyen;Lee, Jae Yun;Kwon, Heongak;Cheon, Se Uk
    • Journal of Wetlands Research
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    • v.17 no.4
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    • pp.380-390
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    • 2015
  • In this study, the major 38 tributaries in Nakdong River were monitored for flow rate and water quality in order to understand the characteristics of the watershed and to find improvement plan. The flow rate and water quality for each target tributary were evaluated based on the monitoring data in 2013~2014 using a statistical package SPSS-22.0. In addition, the tributary grouping method was conducted using a $BOD_5$ concentration/flowrate and TP concentration/flowrate monitoring data. The average values of $BOD_5$, $COD_{Mn}$, TP and TOC concentrations in Gumicheon, Gyeonghocheon, Jincheoncheon, Gisegokcheon, Yonghacheon and Yonghocheon located at Nakdong Waegwan and Nakdong Goryung watershed were high and in the grade of III or IV (5~8 mg/L). The Pearson correlation coefficients of TOC with $BOD_5$, $COD_{Mn}$, and TP were greater (r=0.8, p<0.01) than those of the other water quality parameters (12 species). The tributaries with high values of water quality parameters ($BOD_5$ > 3.0 mg/L, TP > 0.1 mg/L) and flowrate (Q > $0.1m^3/sec$) were selected for improving water quality according to the stream grouping method. Five tributaries (Gumicheon, Gisegokcheon, Yonghacheon, Yeongsancheon, Mijeoncheon and Yonghocheon) were classified as Group I, which require polices and plans for water quality improvement.