Ecology and Resilient Infrastructure

Korean Society of Ecology and Infrastructure Engineering (응용생태공학회)
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Analysis of Channel Changes in Mountain Streams Due to Typhoon Hinnamnor Flood - A Case Study on Shingwangcheon and Naengcheon Streams in Pohang -

태풍 힌남노 홍수로 인한 산지 중소하천의 하도 변화 분석 - 포항 신광천 및 냉천을 사례로 -

  • Chanjoo Lee (Hydro Science and Hydro Engineering Department, Korea Institute of Construction Technology) ;
  • Seong Gi An (River Experiment Center, Hydro Science and Hydro Engineering Department, Korea Institute of Construction Technology) ;
  • Eun-Kyung Jang (Hydro Science and Hydro Engineering Department, Korea Institute of Construction Technology)
  • 이찬주 (한국건설기술연구원 수자원하천연구본부 ) ;
  • 안성기 (한국건설기술연구원 수자원하천연구본부 하천실험센터 ) ;
  • 장은경 (한국건설기술연구원 수자원하천연구본부)
  • Received : 2023.10.10
  • Accepted : 2023.11.29
  • Published : 2023.12.31
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Abstract

This study analyzed morphological changes in the Singwangcheon and Naengcheon streams in Pohang caused by flooding due to Typhoon Hinnamnor. Analysis of the changes in river channel area from the past to recent times using aerial photos and drone-taken images showed that the river width had gradually decreased since the 1960s. However, after the flood, the river width increased again. Changes in the river cross-section before and after the flood show that a large amount of coarse sediment was deposited inside the river bend while the outer bank was eroded. The water levels calculated using HEC-RAS for the pre-flood cross-section based on the flood frequency discharges and estimated discharge from Oer Reservoir were significantly lower than the observed water level, which means that the cross-sectional change was not considered. The results of this study suggest that it is necessary to consider cross-sectional changes due to sediment transport when estimating the flood level of small and medium-sized mountain streams, and it is needed to investigate the geomorphic changes after floods.

본 연구에서는 태풍 힌남노에 의해 발생한 홍수로 인해 초래된 포항 신광천 및 냉천 하도의 지형 변화를 분석하였다. 항공사진 및 드론 영상을 이용하여 과거로부터 최근까지 하도의 평면적 변화를 분석한 결과 1960년대 이래로 하폭이 점차 감소였으나 홍수 이후 하폭이 다시 증가한 것으로 나타났다. 드론 및 현장 조사를 통한 홍수 전후의 단면 변화를 보면 만곡부 내측에 다량의 토사가 퇴적되었고 외측에서는 하안 침식이 발생하였다. 오어저수지의 자료와 빈도홍수량을 이용하여 홍수 전 단면을 기초로 HEC-RAS를 이용하여 산정한 홍수위는 실제 관찰된 수위에 비해 크게 낮았는데, 이는 홍수로 인한 단면 변화가 반영되지 않은데 기인한 것으로 판단된다. 본 연구의 결과를 고려할 때 중소하천의 홍수위 산정 시 토사 운반으로 인한 단면 변화를 고려하는 것이 중요하며 홍수 직후의 지형학적 변화를 조사하는 것이 필요하다.

Keywords

Acknowledgement

본 연구는 한국건설기술연구원 주요사업(기후위기 대응 물문제 해결형 이슈 발굴 및 미래선도 기술 개발(20230155))의 연구비 지원으로 수행되었습니다.

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