Analysis of the vegetation effects on the flow in Chopyeong Island of the Imjin River using a HEC-RAS 2D model

Du Han Lee; Dong Sop Rhee

doi:10.3741/JKWRA.2023.56.9.575

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2023 Vol.56, Issue 9 Preview Page Next Page

Research Article

Analysis of the vegetation effects on the flow in Chopyeong Island of the Imjin River using a HEC-RAS 2D model HEC-RAS 2D 모형을 이용한 임진강 초평도 식생이 흐름에 미치는 영향 분석

30 September 2023. pp. 575-586

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Abstract

River vegetation has important functions such as providing a habitat for the river ecosystem and physical stability of the river bank. It also has adverse effects such as aggravating flood damages due to the increase in roughness coefficient and drag forces. River vegetation management is very important in finding a balance between flood and ecological management. There are still many uncertainties about the effect of vegetation on rivers. In this study, in order to analyze the effect of vegetated flow, the flow patterns according to the vegetation roughness are analyzed through a two-dimensional unsteady flow model for Chopyeong island of the Imjin River. According to the results of the 2D flow analysis using the HEC-RAS 2D model, the velocity distribution in the bend of the Imjin River was greatly affected by the vegetation roughness of Chopyeong Island. The formation of the main flow outside the bend of Chopyeong Island during flooding is presumed due to the influence of tree and grass on Chopyeong Island. If tree are distributed throughout Chopyeong Island, the velocity outside the bend is expected to be higher. River vegetation causes the effect of raising the water level, and could cause a change in the velocity distribution.

Keywords

River vegetation roughness

Imjin river

Chopyeong island

2D unsteady model

HEC-RAS 2D

하천 식생은 하천 생태계의 서식처 제공과 하안의 물리적 안정 등의 중요한 기능을 한다. 그러나 조도계수와 항력의 증가로 홍수 피해 가중 등의 악영향을 미치기도 한다. 하천 식생 관리는 홍수와 생태 관리의 균형점을 찾는다는 점에서 매우 중요하다. 그러나 식생이 하천에 미치는 영향에 대해서는 아직도 불확실한 것이 많다. 본 연구에서는 식생이 흐름이 미치는 영향을 분석하기 위하여 임진강 초평도 구간을 대상으로 식생 조도 설정에 따른 흐름 양상을 2차원 부정류 모형을 통해 분석하였다. HEC-RAS 2D 모형에 의한 2차원 흐름 해석 결과에 의하면 초평도 식생 조도에 따라 임진강 만곡부의 유속 분포가 크게 영향을 받는 것으로 나타났다. 현재와 같이 초평도 만곡부 외측에 홍수시에 주흐름이 형성되는 것은 초평도의 목본과 초본의 영향으로 판단된다. 초평도 전체에 목본류가 분포하면 만곡부 외측의 유속이 더욱 강하게 나타날 것으로 예상된다. 하천의 식생은 단순히 수위를 상승시키는 영향만 발생시키는 것이 아니라 유속 분포 변화를 유발할 수 있음을 확인하였다.

키워드

하천 식생 조도

임진강

초평도

2차원 부정류 모형

HEC-RAS 2D

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Information

Publisher :KOREA WATER RESOURECES ASSOCIATION
Publisher(Ko) :한국수자원학회
Journal Title :Journal of Korea Water Resources Association
Journal Title(Ko) :한국수자원학회 논문집
Volume : 56
No :9
Pages :575-586
Received Date : 2023-08-16
Revised Date : 2023-09-08
Accepted Date : 2023-09-08
DOI :https://doi.org/10.3741/JKWRA.2023.56.9.575

Journal of Korea Water Resources Association 한국수자원학회 논문집 ISSN:2799-8746(Print) 2799-8754(Online)

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