Design flood level at Han River Estuary should be calculated using unsteady flow model

Kyong Oh Baek; Dong Yeol Lee

doi:10.3741/JKWRA.2024.57.11.969

All Issue

2024 Vol.57, Issue 11 Preview Page

Technical Note

Design flood level at Han River Estuary should be calculated using unsteady flow model 한강하류 감조구간에서 계획홍수위는 부정류로 계산해야 한다

30 November 2024. pp. 969-975

PDF XML

Abstract

The Han River Estuary is one of the river reach in South Korea with the largest tidal variation. In such tidal river reach, performing an unsteady flow simulation that considers the effects of tides is appropriate for reflecting the actual conditions when determining the design flood level. For this reason, the river design standards were revised in 2018 to mandate unsteady flow simulations. However, in the recent (2020) Han River Basic Plan, the design flood level for the downstream tidal reach of the Han River was determined and announced using a gradually varied flow simulation instead of an unsteady flow simulation. This study compares the design flood levels by performing an unsteady flow simulation for the downstream reach of the Han River, including the Imjin River. The results show that the flood levels along the entire downstream reach of the Han River, from the Yu-do to downstream of the Shingok Weir, were reduced compared to the design flood levels. The difference in flood levels upstream of the Shingok Weir to the Paldang Dam was negligible when simulating semi-unsteady flow model. Since the downstream of the Shingok Weir in the Han River is a tidal zone that is influenced by the tides of the West Sea, it seems necessary to reconsider the design flood level for this reach by conducting a more rigorous and realistic unsteady flow simulation.

Keywords

Han River Estuary

Tidal reach

Design flood level

Unsteady flow

Varied flow

한강 하류 감조구간은 우리나라에서 가장 조위차이가 큰 하천구간 중 하나이다. 이러한 감조하천구간은 계획홍수위 산정 시 조석의 영향을 고려할 수 있는 부정류 모의를 수행하는 것이 현상을 반영하는데 적절하며, 그 이유로 2018년 하천설계기준은 부정류 모의를 의무화하는 것으로 개정되었다. 그런데 최근(2020년) 한강하천기본계획에서는 한강 하류 감조구간의 계획홍수위를 부정류 대신 부등류 모의로 산정하여 고시한 바 있다. 본 연구에서는 임진강 포함 한강하류구간을 부정류 모의하여 계획홍수위와 차이를 비교하였다. 그 결과 한강은 법정 기점인 유도부터 신곡보 하류까지 구간 전체에 걸쳐 홍수위가 계획홍수위에 비해 저감된 반면, 신곡보 상류부터 팔당댐까지는 semi-부정류 모의의 경우 홍수위 차이가 미미하였다. 한강 신곡보 하류부는 계획홍수량 유하시에도 서해 조석을 받는 감조구간임이므로 이 구간만이라도 부정류 모의를 통해 보다 엄밀하고 현실적인 계획홍수위를 재고시할 필요성이 있어 보인다.

키워드

한강하류

감조구간

계획홍수위

부정류

부등류

References

Baek, K.O., and Yim, D.H. (2011). "Flow characteristics induced by shift and modification of submerged weir at Han River estuary." Journal of the Korean Society of Civil Engineers, Vol. 31, No. 2B, pp. 109-119.

Gyeonggi Province (1985). Gyeonggi district Han River comprehensive development project basic plan.

Kim, S.H., Kim, W., and Choi, H.S. (2003). "Analysis of tidal effect on the Han and Imjin River." Journal of Korea Water Resources Association, Vol. 36, No. 2, pp. 301-313.

10.3741/JKWRA.2003.36.2.301

Korea Water Resources Association (KWRA). (2018). Comparison table of new and revised river design standards.

Ministry of Construction (1988). Han River lower stream coastal development plan.

Ministry of Construction (1989). Han River lower stream coastal development plan.

Ministry of Construction and Transportation (MOCT) (2002). Han River basic plan report.

Ministry of Environment (ME) (2024). Imjin River basic plan re- establishment strategic environmental impact assessment report.

Ministry of Land, Infrastructure and Transport (MOLIT) (2020). Han River basic plan report.

Ministry of Land, Transport and Maritime Affairs (MOLTMA). (2011). Imjin River basic plan report.

Park, C.G., and Baek, K.O. (2017). "Reconsideration of evaluating design flood level at Imjin River estuary." Journal of Korea Water Resources Association, Vol. 50, No. 9, pp. 617-625.

10.3741/JKWRA.2017.50.9.617

Seo, I.W., Song, C.G., and Lee, M.E. (2008). "Flow and mixing behavior at the tidal reach of Han River." Journal of the Korean Society of Civil Engineers, Vol. 28, No. 6B, pp. 731-741.

Seoul Metropolitan Government (1983). Han River comprehensive development basic plan.

Seoul Metropolitan Government (1992). Safety review of river embankments in Seoul and establishment of comprehensive flood control measures.

Yoon, B.I., and Woo, S.B. (2012). "Analysis of tidal asymmetry and flood/ebb dominance around the yeomha channel in the han river estuary." Journal of Korea Water Resources Association, Vol. 45, No. 9, pp. 915-928.

10.3741/JKWRA.2012.45.9.915

Yu, J.H., Kim, H.J., Namgung, D., and Cho, Y.S. (2005). "Analysis of tidal effects with two-dimensional numerical model in Han- River." Proceedings of KSCE Conference, pp. 1871-1875.

Information

Publisher :KOREA WATER RESOURECES ASSOCIATION
Publisher(Ko) :한국수자원학회
Journal Title :Journal of Korea Water Resources Association
Journal Title(Ko) :한국수자원학회 논문집
Volume : 57
No :11
Pages :969-975
Received Date : 2024-09-19
Revised Date : 2024-10-10
Accepted Date : 2024-10-11
DOI :https://doi.org/10.3741/JKWRA.2024.57.11.969

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

All Issue