Journal of Korea Water Resources Association (한국수자원학회논문집)

Korea Water Resources Association (한국수자원학회)
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Numerical analysis of lateral geomorphology changes by channel bed deposition and bank erosion at the river confluence section

합류부 구간에서의 하상퇴적과 하안침식에 의한 평면적 하도변화 수치모의

  • Ji, Un (Hydro Science and Engineering Research Institute, Korea Institute of Civil Engineering and Building Technology) ;
  • Jang, Eun Kyung (Hydro Science and Engineering Research Institute, Korea Institute of Civil Engineering and Building Technology)
  • 지운 (한국건설기술연구원 수자원.하천연구소) ;
  • 장은경 (한국건설기술연구원 수자원.하천연구소)
  • Received : 2015.12.28
  • Accepted : 2016.03.11
  • Published : 2016.05.31
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Abstract

The confluence section of rivers forms complex flow pattern due to inflow discharge variation at the mainstream and tributary. Due to complex flow characteristics, bed change and bank erosion at the local section produce lateral geomorphology changes in rivers. In this study, bankline change by bank erosion and bed change were simulated using CCHE2D of 2-dimensional numerical model for quantitative analysis of lateral changes in the confluence section of South Han River and Geumdang Stream. As a result, bankline at the left-side channel of the mainstream was largely changed in the downstream section of the confluence compared to the upstream section. Also, bank erosion in the tributary was hardly occurred and bankline at the left-side tributary and right-side main stream moved to riverside land due to decreased velocity and deposition.

하천의 합류부 구간은 본류와 지류에서 유입되는 유량의 크기가 달라 복잡한 흐름을 형성하게 되며 이러한 흐름으로 인한 국부적인 구간에서의 하상변동 및 하안침식은 하도의 평면적 변화를 야기할 수 있다. 본 연구에서는 이러한 합류부 구간에서의 평면적 하도변화를 분석하기 위해 남한강과 금당천 합류부 지점을 대상으로 하상 퇴적 및 하안침식에 의한 하안선 이동을 2차원 수치모형인 CCHE2D를 활용하여 모의하였다. 모의결과, 본류의 좌안에서는 합류 전 구간에 비해 합류 후 구간에서의 하안선 이동 현상이 더 크게 발생한 것을 확인할 수 있었다. 또한 지류에서의 하안침식은 거의 발생하지 않으며, 지류 좌안과 합류 전 본류 우안에서는 유속 저하와 퇴적으로 인해 하안선이 제외지 쪽으로 이동하는 것을 확인하였다.

Keywords

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