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Development and assessment of pre-release discharge technology for response to flood on deteriorated reservoirs dealing with abnormal weather events

이상기후대비 노후저수지 홍수 대응을 위한 사전방류 기술개발 및 평가

  • 문수진 (주식회사 에임스) ;
  • 정창삼 (인덕대학교 스마트건설방재학과 ) ;
  • 최병한 (한국농어촌공사 농어촌연구원) ;
  • 김승욱 (아신씨엔티 주식회사) ;
  • 장대원 (주식회사 엘아이지시스템 재난안전연구소)
  • Received : 2023.10.11
  • Accepted : 2023.11.01
  • Published : 2023.11.30

Abstract

With the increasing trend of extreme rainfall that exceeds the design frequency of man-made structures due to extreme weather, it is necessary to review the safety of agricultural reservoirs designed in the past. However, there are no local government-managed reservoirs (13,685) that can be discharged in an emergency, except for reservoirs over a certain size under the jurisdiction of the Korea Rural Affairs Corporation. In this case, it is important to quickly deploy a mobile siphon to the site for preliminary discharge, and this study evaluated the applicability of a mobile siphon with a diameter of 200 mm, a minimum water level difference of 6 m, 420 (m2/h), and 10,000 (m2/day), which can perform both preliminary and emergency discharge functions, to the Yugum Reservoir in Gyeongju City. The test bed, Yugum Reservoir, is a facility that was completed in 1945 and has been in use for about 78 years. According to the hydrological stability analysis, the lowest height of the current dam crest section is 27.15 (EL.m), which is 0.29m lower than the reviewed flood level of 27.44 (EL.m), indicating that there is a possibility of lunar flow through the embankment, and the headroom is insufficient by 1.72 m, so it was reviewed as not securing hydrological safety. The water level-volume curve was arbitrarily derived because it was difficult to clearly establish the water level-flow relationship curve of the reservoir since the water level-flow measurement was not carried out regularly, and based on the derived curve, the algorithm for operating small and medium-sized old reservoirs was developed to consider the pre-discharge time, the amount of spillway discharge, and to predict the reservoir lunar flow time according to the flood volume by frequency, thereby securing evacuation time in advance and reducing the risk of collapse. Based on one row of 200 mm diameter mobile siphons, the optimal pre-discharge time to secure evacuation time (about 1 hour) while maintaining 80% of the upper limit water level (about 30,000 m2) during a 30-year flood was analyzed to be 12 hours earlier. If the pre-discharge technology utilizing siphons for small and medium-sized old reservoirs and the algorithm for reservoir operation are implemented in advance in case of abnormal weather and the decision-making of managers is supported, it is possible to secure the safety of residents in the risk area of reservoir collapse, resolve the anxiety of residents through the establishment of a support system for evacuating residents, and reduce risk factors by providing risk avoidance measures in the event of a reservoir risk situation.

최근 이상기후로 수공 구조물의 설계빈도를 상회하는 극한호우의 증가 경향이 뚜렷함에 따라 과거에 설계된 농업용 저수지의 안전성 검토가 필요하다. 그러나 한국농어촌공사 관할 일정 규모 이상의 저수지를 제외한 지자체 관리 저수지는 비상시 긴급 방류가 가능 저수지는 전무하다(13,685개소). 이러한 경우 이동식 사이펀을 현장에 빠르게 투입하여 사전 방류하는 방법이 긴요하며, 본 연구에서는 사전 및 긴급방류 기능을 동시에 수행할 수 있는 직경 200 mm, 최소 수위차 6 m, 420(m2/h), 10,000(m2/day)의 이동식 사이펀을 경주시 유금저수지를 대상으로 적용 가능성을 평가하였다. 테스트베드인 유금 저수지는 1945년 준공되어 공용기간이 78년 정도 경과한 시설물로 수문학적 안정성 분석 결과 현재 댐마루 구간의 최저높이는 27.15(EL.m)로 검토 홍수위 27.44(EL.m) 보다 0.29 m 낮아 제방을 통한 월류 가능성이 있고 여유고도 1.72 m 부족한 것으로 나타나 수문학 안전성을 확보하지 못하는 것으로 검토되었다. 유금저수지는 수위-유량 계측이 주기적으로 이루어진지 얼마 되지 않아 저수지의 수위-유량 관계 곡선식을 명확하게 확립하기 어려워 수위-용적 곡선을 임의로 도출하였으며 도출된 곡선을 기반으로 중소규모 노후저수지 운영 알고리즘을 통해 사전방류시간, 여수로 방류량을 고려하고 빈도별 홍수량에 따른 저수지 월류시간을 예측함으로써 사전에 대피 시간을 확보하고 붕괴위험을 저감할 수 있는 기술을 확보하였다. 직경 200 mm 이동식사이펀 1열 기준, 30년 빈도 홍수량 유입 시 상한수위 기준 80% 수준(약 30,000 m2)을 유지하면서 주민대피 시간(약 1시간)을 확보할 수 있는 최적 사전방류시간은 12시간 이전으로 분석되었다. 중소규모 노후저수지를 대상으로 사이펀 활용 사전방류기술 및 저수지 운영 알고리즘에 따라 이상기후 대비 사전에 방류를 시행하고 관리자의 의사결정을 돕는다면, 저수지 붕괴 위험지역 내의 주민들의 안전을 확보하고 주민대피 지원체계 구축을 통해 주민들의 불안감 해소, 저수지 위험상황 시 위험회피 수단 제공으로 위험요소 감소가 충분히 가능하다.

Keywords

Acknowledgement

이 논문은 행정안전부 기후변화대응 AI 기반 풍수해 위험도 예측기술개발사업의 지원을 받아 수행된 연구임(2022-MOIS61-005(RS-2022-ND634032)).

References

  1. Babaeyan-Koopaei, K., Valentine, E.M., and Ervine, D.A. (2002). "Case study on hydraulic performance of Brent Reservoir siphon spillway." Journal of Hydraulic Engineering, Vol. 128, No. 6, pp. 562-567.  https://doi.org/10.1061/(ASCE)0733-9429(2002)128:6(562)
  2. Boatwright, J.D. (2014). Air-regulated siphon spillway: Performance, modeling, design, and construction. Master Thesis, Clemson University, Clemson, SC, U.S. 
  3. Choi, B.H., and Ryu, C.H. (2017). "Preparing the failure forecast for thereservoir (fill dam) for doubling the performance utilization of the reservoir disaster prevention measurement business." Journal of the Korea Water Resources Association, Vol. 50, No. 3, pp. 36-44. 
  4. French, M.J., and Widden, M.B. (2001). "The exploitation of low-head hydropower by pressure interchange with air, using siphons." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, Vol. 215, No. 2, pp. 223-230.  https://doi.org/10.1243/0957650011538497
  5. Houich, L., Ibrahim, G., and Achour, B. (2009). "Experimental comparative study of siphon spillway and over-flow spillway." Courrier du Savoir, Vol. 9, pp. 95-100. 
  6. James, W., and Young, B.C. (2001). "An approach to modeling realtime control of dynamic and static radial and sluice gates within EXTRAN." Journal of Water Management Modeling, Vol. 9, pp. 355-382.  https://doi.org/10.14796/JWMM.R207-22
  7. Kim, K.S., and Park, K.B. (2016). "Study on the hydrological safety of small old reservoirs." Advanced Science and Technology Letters, Vol. 140, pp. 83-86. 
  8. Ministry of Environment (ME) (2019). Standard guidelines for estimating flood volumes. No. 11-148000-001604-14, pp. 35-42. 
  9. Ministry of Land, Transport and Maritime Affairs (MLTM) (2011). Improvement and supplement of probability rainfall. No. 11-1611000-001995-01, pp. 43-51. 
  10. Park, D.S., and Oh, J.H. (2016). "Potential hazard classification of aged cored fill dams." The Journal of Engineering Geology, Vol. 26, No. 2, pp. 207-221.  https://doi.org/10.9720/KSEG.2016.2.207
  11. Park, K.B., Kim, K.S., Cha, S.H., and Ahn, S.S. (2016). "Assesment on flood control ability of small agricultural reservoir due to climate change." Proceeding of Korean Society of Hazard Mitigation Conference, p. 278. 
  12. Yoon, D.K. (2010). "Investigation of the methods for increasing flood control capacity of reservoir." Journal of Korean National Committee on Irrigation and Drainage, No. 45, pp. 37-42.