Ecology and Resilient Infrastructure

Korean Society of Ecology and Infrastructure Engineering (응용생태공학회)
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Determination of Floodplain Restoration Area Based on Old Maps and Analysis on Flood Storage Effects of Flood Mitigation Sections

고지도를 활용한 홍수터 복원 구역 선정 및 홍수완충공간의 홍수 저류효과 분석

  • Dong-jin Lee (Department of Hydro Science and Engineering Research, Korea Institute of Civil Engineering and Building Technology) ;
  • Un Ji (Department of Hydro Science and Engineering Research, Korea Institute of Civil Engineering and Building Technology) ;
  • Sanghyuk Kim (Department of Water Resources, Haeju Engineering) ;
  • Hong-Kyu Ahn (Department of Hydro Science and Engineering Research, Korea Institute of Civil Engineering and Building Technology) ;
  • Eun-kyung Jang (Department of Hydro Science and Engineering Research, Korea Institute of Civil Engineering and Building Technology)
  • 이동진 (한국건설기술연구원 수자원하천연구본부 ) ;
  • 지운 (한국건설기술연구원 수자원하천연구본부 ) ;
  • 김상혁 (해주엔지니어링(주) 수자원부) ;
  • 안홍규 (한국건설기술연구원 수자원하천연구본부 ) ;
  • 장은경 (한국건설기술연구원 수자원하천연구본부 )
  • Received : 2023.04.12
  • Accepted : 2023.05.24
  • Published : 2023.06.30
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Abstract

To reduce the damage of extreme flooding caused by climate change and to create flood mitigation sections in a nature-friendly riparian area, it is necessary to restore the floodplain area by referring to the past floodplain section of the current inland waterfront area before the levee was built. This study proposed a method of selecting a location for floodplain restoration using old maps of the Geum River study section and analyzed the effect of flood level reduction through unsteady flow numerical simulations using the floodplain as a flood mitigation space. As a result of analyzing changes in the river areas using old maps, the river section was estimated to gradually reduce by 27.8% (1,059,380 m2) in 2020 compared to 1919, and it was found to have an effective storage capacity of 2,200,868 m3 when restored to offline storage. The flood level and discharge control effects analyzed based on HEC-RAS unsteady flow simulation were 16 cm and 219.01 m3/s, respectively, in the downstream cross-section. In the numerical simulation in this paper, the flood mitigation space was applied as an offline reservoir. The effect of reducing the flood level may differ if levee retreat/relocation is applied.

기후변화로 인한 극한홍수의 피해를 저감하면서 동시에 자연친화적 수변구역의 홍수완충공간을 조성하기 위해 제방이 건설되기 이전의 홍수범람 범위와 하천구역을 참조하여 홍수터 복원을 수행할 필요가 있다. 이에 본 연구에서는 금강 대상구간에 대해 고지도를 활용하여 홍수터 복원가능 공간의 입지 선정 방법을 제안하고 홍수터를 홍수완충공간으로 활용할 경우 홍수위 저감 효과를 부정류 수치모의를 통해 분석하였다. 고지도를 활용하여 하천구역 변화를 분석한 결과, 1919년에 비해 2020년 하천구역 면적이 단계적으로 총 27.8% 감소 (1,059,380 m2)한 것으로 추정되었으며, 과거 홍수범람 구역이었던 제내지를 offline 저류지로 복원할 경우 2,200,868 m3의 유효 저류용량을 가지는 것으로 나타났다. HEC-RAS 부정류 모의를 통해 분석한 홍수위와 홍수량 조절 효과는 대상구간의 하류 단면에서 16 cm와 219.01 m3/s인 것으로 나타났다. 본 논문의 수치모의에는 홍수완충공간이 offline 저류지 형식으로 적용되었으며, 제방 후퇴/이설을 통한 홍수터의 확대가 적용될 경우 홍수위 저감 효과는 다르게 나타날 수 있다.

Keywords

Acknowledgement

본 논문은 환경부의 재원으로 한국환경산업기술원의 기후변화대응환경기술개발사업의 지원을 받아 연구되었습니다 (과제번호 022003460002).

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