Ecology and Resilient Infrastructure

Korean Society of Ecology and Infrastructure Engineering (응용생태공학회)
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Temporal Adjustment of Channel Geometry and Spatial Changes in Riverbed Materials along the Downstream Channels of Large Dams in the Geum River basin

금강유역 대형댐 하류 하도지형 경년변화 및 하상재료 종적변이 연구

  • Ock, Giyoung (Department of Ecosystem Assessment, National Institute of Ecology,) ;
  • Choi, Mikyoung (International Water Resources Research Institute, Chungnam National University) ;
  • Park, Hyung-Geun (Department of Ecosystem Assessment, National Institute of Ecology,)
  • 옥기영 (국립생태원 생태평가연구실) ;
  • 최미경 (충남대학교 국제수자원연구소) ;
  • 박형근 (국립생태원 생태평가연구실)
  • Received : 2019.12.13
  • Accepted : 2019.12.19
  • Published : 2019.12.31
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Abstract

This study investigated longitudinal changes in riverbed materials properties and temporal alteration of river channel geomorphology in the Geum River basin, where two multipurpose dams(Yongdam Dam and Daecheong Dam) were built in upstream area. We carried out grain size distribution analyses and measured soil organic matter contents of riverbed materials taken at the upper and lower sites of the two large dams. We also estimated the channel width, bar area and vegetation encroachment using the oldest map and aerial photographs taken before and after the construction of the dams. The results can contribute to increasing understandings of dam induced habitat alteration in river ecosystem.

대형댐 하류의 수용생태계에서는 상류로부터 공급되는 유기물과 토사 이동의 양적 단절과 질적 변환에 따라 서식처의 물리화학적 교란이 발생하게 된다. 본 연구는 금강 중상류역을 대상으로 대형댐에 의한 하상재료와 토양의 종적변화, 그리고 대형댐 건설 이후 하류 하천의 하도지형 변화를 정량적으로 파악하였다. 댐 상·하류 하상재료 입도분석 결과, 용담댐 구간은 상·하류 모두 호박돌, 굵은자갈로 조립화되어 있었으며, 대청댐 구간은 댐하류에서 중간입경이 가는자갈로 급격히 감소하고 모래비율이 급격히 증가하였다. 토양유기물은 두 개의 댐 모두 하류에서 뚜렷하게 증가하였다. 고지도와 항공사진을 이용하여 대청댐 하류의 하도지형을 분석한 결과, 사주면적의 감소와 사주 내 식생비율의 급격한 증가, 사행도와 저수로폭의 감소 경향을 정량적으로 파악할 수 있었다. 이러한 결과들은 댐 건설에 따른 서식처 변화의 인과관계를 파악하여 댐 하류 조절하천의 자연성을 회복하기 위한 복원관리 방안을 도출하는데 적용될 수 있을 것이다.

Keywords

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