• Title, Summary, Keyword: Gumi reservoir

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Seasonal Variation of the Surface Heat Budget in the Gumi Reservoir of Nakdong River (낙동강 구미 보의 수면 열수지 계절 변화)

  • Kim, Hak-Yun;Seo, Kwang-Su;Cho, Chang-Bum;Kim, Hae-Dong
    • Journal of Environmental Science International
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    • v.25 no.8
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    • pp.1057-1063
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    • 2016
  • The heat budget is investigated in the Gumi Reservoir of the Nakdong river. In warm climate season, solar radiation effects play a important role in the change of water temperature. The features of the surface heat balance are almost derived by the latent heat flux and the solar radiation flux. On the other hand, in cold climate season, change of heat stored in the water is mainly dominated by latent and sensible heat transfer between water and air, since flux of solar radiation and loss of outgoing long wave radiation balance approximately. For the annual averages, net flux of radiation, evaporation(latent heat) loss are dominant in the Gumi reservoir. The evaporation losses are dominant from spring to early winter. This means that the Gumi reservoir rolls like a lake of thermal medium or deep depth.

Micro-meteorological Characteristics during the Steam Fog over the Gumi Reservoir of Nakdong River (낙동강 구미 보의 증기 안개 발생 시의 미기상학적 특성)

  • Kim, Hae-Dong;Cho, Chang-Bum;Seo, Kwang-Su
    • Journal of Environmental Science International
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    • v.25 no.3
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    • pp.405-415
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    • 2016
  • We analyzed the micro-meteorological characteristics during typical steam fog over the Gumi Reservoir of Nakdong river with the field observation data for recent 2 year(1 April 2013~31 March 2015) collected by the national institute of meteorological research, KMA. Steam fog occur when the cold drainage flows over the warm water surface. As the sensible and latent heat from water are provided to the air, the instability of lower atmosphere is increased. The resultant vertical mixing of warm, moist air near water surface and cold air aloft causes the formation of status cloud. The convection strengthened by radiative cooling of the upper part of the stratus causes the fog to propagate downward. Also, the temperature at the lowest atmosphere is increased rapidly and the inversion near surface disappear by these processes when the fog forms. The increase of wind speed is observed because the downward transportation of momentum is caused by vertical mixing.

On the Steam Fog in the Gumi Reservoir of Nakdong River (낙동강 구미 보의 증기 안개에 관한 연구)

  • Kim, Hae-Dong;Cho, Chang-Bum;Seo, Kwang-Su
    • Journal of Environmental Science International
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    • v.25 no.1
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    • pp.163-171
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    • 2016
  • We analyzed the characteristics of fog formation in the Gumi Reservoir of Nakdong river with the field observation data for recent 2 years (1 April 2013~31 March 2015) collected by the national institute of meteorological research, KMA. In early morning, we frequently observe the steam rising from the water surface. The fog occurs from adding water vapor into the air. We call the fog as steam fog. Steam fogs occur when cold, dry air mixes with warm, moist air above a water surface. The steam fog appears mainly in autumn under the following conditions; (1) sensible heat is positive values ($10{\sim}20W/m^2$), (2) latent heat is more positive values ($25{\sim}35W/m^2$) than sensible heat, (3) cloudless nights with light winds (about 1.5 m/s), (4) under condition(3), mountainous winds easily blows into the reservoir.

Development of Downstream Turbid Water Management System Using SWAT and KoRiv1 Dynamic Water Quality Simulation Model (SWAT 및 KoRiv1 모형을 활용한 하류하천 탁도관리 시스템구축)

  • Noh, Joon-Woo;Kim, Jeong-Kon;Lee, Sang-Uk
    • Journal of Environmental Science International
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    • v.18 no.9
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    • pp.1035-1043
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    • 2009
  • High turbid water in the River has been one of the major concerns to the downstream residence. Especially in the Nakdong River basin severe turbid water problem occurred in year 2002 and 2003 due to the typhoon Rusa and Maemi consecutively. The main objective of this study is to develop turbid water management system in reservoir downstream of the Nakdong River combining physically based semi-distributed hydrologic simulation model SWAT with 1-dimensional dynamic water quality simulation model. SWAT model covers the area from the upstream of the Imha and Andong reservoir to the Gumi gage station for the purpose of estimating flow rates and suspended sediment of the tributaries. From year 1999 to 2007 runoff simulation for 8 years $R_{eff}$ and $R^2$ ranges $0.46{\sim}0.9$, $0.54{\sim}0.99$ respectively. Through the linkage of models, outputs of SWAT model such as suspended sediment and flow rates of the tributaries can be incorporated into the 1-dimensional dynamic water quality simulation model, KoRiv1 to support joint reservoir operation considering the turbidity released from Imha and Andong reservoir. The applicability of model simulation has been tested for year 2006 and compared with measured data.