• Title/Summary/Keyword: 낙동강 하구

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Distribution of Marine Debris collected from the Sandbar Coastline after the Passage of Typhoons, Nakdong River Estuary (태풍 내습후 낙동강 하구 사주해안의 쓰레기 분포)

  • Park, Son;Yoon, Han-Sam
    • Proceedings of KOSOMES biannual meeting
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    • 2007.11a
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    • pp.15-21
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    • 2007

  • Using field observations, this study estimated the total weight and types of marine debris along the coast of Jinu Island in the Nakdong River Estuary after typhoons Usagi and Nari had passed. A numerical wave m며el was used to calculate the spatial wave height distribution at the time of the typhoons' passage. This study found that the total accumulation of marine debris deposited on the coast after the two typhoons had passed was about $5,769.86kg/day/km^2$ at this sitε which was 14.42 times more than during normal weather. The wave height distribution in the sea off Jinu Island, based on numerical modeling， was $4.1^{\sim}3.5$ m, which was 1.0-2.5 times greater than for the case of other islands. Therefore, it is likely that the concentration of wave energy led to the deposition of marine debris.

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Prediction of Topographic Change in the Estuary of Nakdong River and Analysis of Its Contribution by External Force Condition (낙동강 하구 지형변화 예측 및 외력조건에 따른 기여도 분석)

  • Kim, Kang-Min;Lee, Joong-Woo
    • Journal of Navigation and Port Research
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    • v.43 no.1
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    • pp.64-71
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    • 2019

  • It is very important to understand the mechanism of estuary topographic changes for the study of estuary management and treatment methods. In this study, the effects from the land-side, such as rainfall, river discharge, sediment discharge, and sea side, such as tide, tidal current, wave and surface sediments related to the topographic changes of the Nakdong river estuary were investigated and analyzed. Based on the analyzed data, topographic modeling was performed to analyze the topographic change and contribution of external force conditions. As a result of numerical modeling, the topographic change showed that erosion that predominates in the water directly affected by the discharge of the estuary barrage. The deposition predominates in the indirectly affected tideland. As sediments moved along the water way being sorted and distributed by the wave, the deposition predominated in the front of the barrier island. Compared with the deposition dominance, which is the result of the topographic change prediction, the impact of each external force condition gives larger erosion. However, the combined impact of each external force condition showed deposition dominant. Therefore, the topographic changes of the Nakdong river estuary are considered to be the result of various complex external factors. The impacts of each external force condition show the different contribution to each comparison area. These results should be considered when establishing the estuary management method. It must be understood that this is the result of complex interactions.

  • https://doi.org/10.5394/KINPR.2019.43.1.64 인용 PDF KSCI HTML

Seasonal Variation of Nitrogen Loads and Nitrogen Cycling at Tidal Flat Sediments in Nakdong River Estuary (낙동강 하구 갯벌 퇴적물에서 강을 통한 질산염 유입에 따른 질소순환의 계절 변화)

  • Lee, Ji-Young;Kwon, Ji-Nam;An, Soon-Mo
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.17 no.2
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    • pp.120-129
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    • 2012

  • We investigated seasonal variation of sediment-water oxygen and inorganic nitrogen fluxes, and denitrification at tidal flat sediments located in the Nakdong River Estuary from July 2005 to September 2006. Net oxygen fluxes, measured with sediment incubations at in situ temperature, varied from -37.0 to $0.5mmol\;O_2\;m^{-2}\;d^{-1}$. Oxygen fluxes into the sediments from the overlying water increased due to the increased water temperature. Denitrification rate ($4{\sim}2732{\mu}mol\;N\;m^{-2}\;d^{-1}$) in this study was higher compared to the other Korean coast measured with the same method. Denitrification showed the same seasonal variation as oxygen fluxes. Denitrification rate based on $^{15}N$-nitrate showed a strong correlation with nitrate flux into the sediments from the overlying water. Denitrification via "water column supplied nitrate ($D_w$)", calculated from Isotope pairing technique, also correlated well with nitrate flux into the sediments. Nitrate from water column seems to account for seasonal variation of denitrification in Nakdong River Estuary. To understand general patterns and trends of biogeochemical processes of sediments in the Nakdong River Estuary, we categorized biogeochemical fluxes measured in this study according to direction and sizes of fluxes. Type 1(high oxygen and inorganic nitrogen fluxes into the sediments and high denitrification) occurred in summer, whereas Type 2(low oxygen and inorganic nitrogen fluxes into the sediments and low denitrification) occurred in rest of the season. Intertidal flat sediments seem to react sensitively to influence of freshwater from the Nakdong River.

  • https://doi.org/10.7850/jkso.2012.17.2.120 인용 PDF KSCI