기후변화를 고려한 PMP산정에 따른 댐 붕괴시 하류부 침수 영향 분석 (Downstream Innundation Analysis Due to Dam Breach with PMP Condition Considering Climate Change)

서지정보

· 발행기관 : 한국환경기술학회
· 수록지 정보 : 한국환경기술학회지 / 15권 / 3호 / 243 ~ 253페이지
· 저자명 : 장석환, 오지환, 추정호, 임남재

초록

본 연구에서는 실제 소규모 댐을 대상으로 유역 지형에 대한 GIS분석으로 매개변수를 산정하고, 한국최대강수량도를 활용하여 유역의 가능최대강수량(Probable Maxi- mum Precipitation)을 추정하였다. PMP 자체가 극치사상을 뜻하지만, 기후변화에 따라 PMP도 증가할 수 있다고 가정하여 상수전용 댐의 수명을 일반적으로 50년을 기준으로 준공년도의 50년을 더한 2050년을 목표년도로 결정하고, 과거 지점의 연최대강우량을 활용하여 경향성을 분석하였다. 또한 PMP에 따른 홍수량 산정 후 댐 붕괴 시나리오를 작성하고, HEC-RAS의 DAMBRK 모듈을 활용하여 댐 하류부의 유출수문곡선 및 홍수파 해석을 실시하고, 1차원 침수범람도를 작성하였다.
PMP에 따른 PMF 산정결과, 가장 큰 유출량으로 397.97 ㎥/sec로 산정되었고, 기후변화를 고려한 PMF산정 결과, 2050년은 약 17 % 증가하는 479.57 ㎥/sec로 분석되었다. 댐 붕괴 시나리오에 따른 홍수파 해석 결과, 댐 직하류부는 댐파괴 파 이송현상이 탁월하고 계곡부로 월류에 의한 범람 피해는 미미한 것으로 나타났고, 중류부는 계곡부 통과 후 하천폭이 확산되는 지점으로 범람피해가 가장 큰 것으로 분석되었다.

영어초록

In recent, experiencing significant damages in property and human lives from the occurrence of flood damages of various scales each year resulting from unexpected weather changes in Korea. In addition, flood accompanying heavy rain that exceeds the design frequency of major dam and reservoir. Dam and reservoir are very important flooding structure in the aspect of using water resources and preventing disaster because of the characteristics of river in our country with small area, short flow route and steep slope.
In this study, GIS analysis was conducted for basin topography for actual basin to estimate and predict space & time topography factors, and the probable maximum precipitation (PMP) of applied basin and probable maximum flood (PMF) were computed to predict PMP and PMF considering climate change through the frequency analysis of past PMP and literature research. flood wave of downstream through DAMBRK model and HEC-RAS 1 dimension unsteady flow analysis.
PMF estimation result according to PMP showed quartile 2 hours 397.97㎥/sec and PMF estimation result considering climate change showed 479.57㎥/sec that is about 17% increase in PMP in 2050. In addition, the result of flood tracking within reservoir showed that hydrologic stability was thought to be unstable from the overflowing dam crest altitude during PMP inflow. In addition, the result of applying DAMBRK model per scenario showed insignificant damage from overflow to valley part from effective dam destruction transfer phenomenon at upstream of Baekseokcheon that is dam downstream in PMP condition. As for midstream, flooding damage was found to be the biggest as the point of spread after passing valley part. Particularly, it was found that concentrated flooding occurs at the military base and support facilities located at the point of curving towards southwest direction. In addition, it was found that overflow occurs at gentle slope section even though overflow damage is insignificant to the riverbed slope flow point in downstream.

참고자료

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