Hydraulic mixing characteristics at a large-scale confluence of Nakdong and Nam River

Suin Choi; Dongsu Kim; Youngdo Kim; Siwan Lyu

doi:10.3741/JKWRA.2023.56.S-1.1015

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2023 Vol.56, Issue 12S Preview Page Next Page

Research Article

Hydraulic mixing characteristics at a large-scale confluence of Nakdong and Nam River 낙동강 - 남강 합류부 대하천 규모 수리학적 혼합특성 연구

31 December 2023. pp. 1015-1026

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Abstract

The confluence of rivers, where rivers meet, is a place known for complex water mixing dynamics. Sometimes, these rivers flow downstream without mixing. While this non-mixing can pose challenges for water quality management, it also offers the potential for improved water extraction in nearby water intakes (Chilseo). In this study, we analyzed the mixing dynamics at the confluence of the Nakdong River and the Nam River using drone imagery, water quality indicators like Electrical Conductivity, and hydraulic factor Secondary Flow. We found that meandering effects hindered mixing, as shown by the comparison of Secondary Flow and Electrical Conductivity distributions. Additionally, the Chilseo Water Purification Plant downstream of the Nakdong River-Nam River confluence extracted unmixed Nam River water during certain periods.

Keywords

Secondary flow

Confluence

Rozovskii

ADCP

Electrical conductivity

하천의 합류부는 본류와 지류가 만나 복잡한 혼합거동을 보이는 지역으로 두 하천이 혼합되지 않은 채 하류로 이동하는 현상이 발생하기도 한다. 하천이 혼합되지 않고 유지되면 하천의 수질 관리에 어려움을 주거나 남강 합류부 인근 취수장(칠서)에서 취수되는 수체의 특성이 모호할 수 있다. 본 연구에서는 드론 영상과 수질 인자 전기전도도, 수리 인자 2차류를 통해 낙동강과 남강 합류부에서의 혼합거동을 면밀하게 분석하였다. 2차류의 분석은 Rozovskii 방법을 기반으로 2중 나선형 구조의 확인이 용이하게 하였다. 연구 결과 만곡의 영향으로 인해 혼합이 방해 받고 있음을 2차류 분포와 전기전도도 분포의 비교 분석을 통해 확인하였으며, 낙동강-남강 합류부 하류의 칠서 정수장은 해당 시기 혼합되지 않은 남강 수체를 취수하고 있음을 확인하였다.

키워드

2차류

합류부

Rozovskii

ADCP

전기전도도

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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 :12
Pages :1015-1026
Received Date : 2023-09-20
Revised Date : 2023-10-17
Accepted Date : 2023-10-19
DOI :https://doi.org/10.3741/JKWRA.2023.56.S-1.1015

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

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