A small dam is of hydraulic structures, which is always exposed to risk by flood, and it’s very important to ensure structural safety. A probabilistic analysis, quantifying variable as a risk factor to ensure safety of small dam, identifying its coefficient of variation, which has become increasingly important. In this study, the risk of seepage failure of foundation within a small dam was estimated based on flood scenarios by rainfall quantile. The final compound risk was evaluated combining probabilities, related to seepage failure and flood level. The seepage failure probability was estimated by performing seepage analysis depending on the water level difference between upstream and downstream in small dam. The probable flood level was estimated by considering hydraulic uncertainty associated with channel geometry, and movable gate operation during the flooding season, applied a probable flood considering hydrologic uncertainty evaluated by Bayesian approach. The safety evaluation of small dam with probabilistic-based compound risk expect to use the index for hydraulic structure design in the future.

1. 서 론
 2. 해석방법
  2.1 Bayesian 기법을 적용한 수문학적 불확실도해석
  2.2 수리학적 불확실성을 고려한 홍수위 계산
  2.3 홍수에 의한 보(Weir) 구조물의 침투해석
  2.4 복합위험도 산정기법
 3. 복합위험도 산정
  3.1 대상유역 및 시설
  3.2 수문⋅수리학적 불확실성을 고려한 홍수위예측
  3.3 불확실성을 고려한 보 구조물 침투해석
  3.4 복합위험도 산정
 4. 결 론
 REFERENCES

• 남명준((주)신우엔지니어링 융합기술연구소 대리, Assistant Manager, Fusion Research Institute, Sinwoo Engineering CO.,LTD, Seoul) | Nam, Myeong Jun
• 이재영((주)신우엔지니어링 융합기술연구소장, Research Director, Fusion Research Institute, Sinwoo Engineering CO.,LTD, Seoul) | Lee, Jae Young Corresponding author
• 정우영(강릉원주대학교 토목공학과 교수, Professor, Department of Civil Engineering, Gangneung-Wonju Univercity, Gangneung) | Jung, Woo Young
• 신동훈(K-water 융합연구원 인프라안전연구소장, Research Director, Infrastructure Research Center, K-water, Daejeon) | Shin, Dong Hoon