• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.104-104
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• 2023

최근 2017년 청주, 천안의 홍수, 2020년 용담댐 상류와 대청댐 상류의 홍수, 2022년 청주의 도시침수를 비롯한 서울 도심의 침수피해와 같은 홍수 발생은 지역의 국민들에게 막대한 재산상의 피해를 입히고 있다. 국가적 차원에서 치수의 목적을 달성하고 경제적으로 적절한 규모의 수리구조물을 설계하기 위해 하천의 주요지점에 대한 신뢰성 있는 설계홍수량의 제시는 반드시 필요한 현실에 직면해 있다. 특히 해당 지점의 수리시설물은 점빈도분석에 의한 설계홍수량을 적용하나, 관측자료가 없는 미계측 지점에 위치한 수리시설물은 지역빈도분석에 의한 설계홍수량을 산정하여 적용해야 한다. 이에 본 연구에서는 금강 유역을 대상으로 점빈도분석과 지역빈도분석에 의한 설계홍수량 결과를 비교·분석하고자 한다. 지역빈도분석을 위한 수위관측소의 선정은 금강유역 80개 수위관측소 중 장기간 연최대홍수량 자료가 있고 유량자료의 연결성 및 신뢰성이 확보된 46개수위관측소를 대상으로 하였다. 46개 수위관측소의 연최대홍수량 계열을 대상으로 동질성, 독립성 및 이상치 검정을 수행하였으며, 세 가지 검정 모두 적절한 수위 관측소 지점은 36개 지점으로 분석되었다. 36개 수위관측소의 기본통계치(평균, 표준편차, 분산, 왜곡도 및 첨예도)를 산정한 후 3변수 Gamma 분포 계열인 GEV, GLO, GPA의 확률 분포를 적용하였다. 확률 분포별 매개변수는 전산화를 통해 L-모멘트의 차수를 0~4까지 변화시켜 LH-모멘트법에 적용하였다. LH-모멘트법에 의해 산정된 확률 분포들의 매개변수를 적용하여 적합도 검정을 수행하였다. 지역빈도분석을 위해 36개 수위관측소를 K-Means clustering 방법을 통해 4개 지역으로 구분하였다. 이를 통해LH-모멘트의 적정차수와 확률 분포에 따른 점빈도분석(지점 대상)과 지역빈도분석(지역 대상) 결과인 설계홍수량을 산정하였으며, 점빈도분석과 지역빈도분석에 의해 산정된 설계홍수량간의 분석결과를 제시하였다. 본 연구를 통해 수리구조물 설계 시 안정적인 조건 제시 및 관리체계 구축에 기여하고 방재대책 수립 시 경제·사회적 요소를 반영한 합리적 방안을 제시하고자 한다.

• The Journal of the Korea Contents Association
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• v.8 no.3
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• pp.252-263
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• 2008

This study was conducted to derive the optimal regionalization of the precipitation data which can be classified on the basis of climatologically and geographically homogeneous regions all over the regions except Cheju and Ulreung islands in Korea. A total of 65 rain gauges were used to regional analysis of precipitation. Annual maximum series for the consecutive durations of 1, 3, 6, 12, 24, 36, 48 and 72hr were used for various statistical analyses. K-means clustering mettled is used to identify homogeneous regions all over the regions. Five homogeneous regions for the precipitation were classified by the K-means clustering. Using the L-moment ratios and Kolmogorov-Smirnov test, the underlying regional probability distribution was identified to be the generalized extreme value (GEV) distribution among applied distributions. The regional and at-site parameters of the generalized extreme value distribution were estimated by the linear combination of the probability weighted moments, L-moment. The regional and at-site analysis for the design rainfall were tested by Monte Carlo simulation. Relative root-mean-square error (RRMSE), relative bias (RBIAS) and relative reduction (RR) in RRMSE were computed and compared with those resulting from at-site Monte Carlo simulation. All show that the regional analysis procedure can substantially reduce the RRMSE, RBIAS and RR in RRMSE in the prediction of design rainfall. Consequently, optimal design rainfalls following the regions and consecutive durations were derived by the regional frequency analysis.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.5
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• pp.87-92
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• 2009

It has been considered only with the concerned regional damage costs whenever the restoration and flood control measures were established in Korea. If the relationship between regional flood frequency and damages is quantitatively analyzed, more resonable and reliable countermeasure for flood protection and restoration can be proposed. Historical data ('70~'07) about flood damage in Korea were utilized and analyzed to present such relationship using the point frequency analysis. Also, the quadrant analysis was employed to divide into 4 categories: high frequency-high damage, high frequency-low damage, low frequency-high damage, and low frequency-low damage. If the results from this study were utilized well in specific cities and counties in Korea, it would be helpful to establish the countermeasures and action plans for flood protection because it was possible to compare with the relationship between flood frequency and damage of each region. And it would be the fundamental data for estimating the effect of future flood protection plan.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.205-205
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• 2023

지역 빈도 분석과 점 빈도 분석은 하천 기본계획 및 수공 구조물의 설계에 있어 재현기간 별 확률강우량을 산정하기 위한 방법이다. 점 빈도 분석은 자료의 수가 부족하여 높은 재현기간에 대한 확률강우량을 산정하기에 어려운 점이 있다. 2019년도부터 사용되고 있는 지역빈도분석 방법은 이러한 점을 보완해주고 있다. 지역빈도분석을 수행하기 위해서는 지역의 동질성을 확인하는 과정이 가장 중요한 과정이다. 이러한 동질성을 판단하기 위하여 K-means등의 군집분석과 L-moment 법 등을 사용하고 있다. 이러한 차이점으로 인해 두 방법 간의 정확성은 비교가 어려우나 서로 간의 장점, 단점과 결과 간의 차이를 기반으로 산간지역이 많은 강원도와 같은 지역에 대한 확률강우량 산정의 적절한 방법을 판단해보고자 본 연구를 진행하였다. 지역 빈도 분석은 강원도에 위치한 48개 관측소의 강우 자료 수집 후 고도, 위치, 지속시간 별 강우량을 변수로 지정하고 K-means 분석을 통해 6개의 군집으로 구분하여 수행되었다. 이질성 척도는 관측 자료와 500번의 모의 수행을 통해 결정하였다. 이후 분석된 군집이 동질한 경우 확률분포형에 적합시켜 확률강우량을 산정하였다. 점 빈도 분석은 지역 빈도 분석에서 결정된 군집에서의 최대 강우량과 최소 강우량 관측소의 자료를 이용하여 수행하였다. 본 연구에서는 점빈도분석과 지역빈도분석의 결과를 비교하였으며, 두 가지 분석 방법에 따른 차이의 발생원인 및 특성을 결론으로 제시하였다.

• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.164.1-164.1
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• 2009

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.5
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• pp.70-82
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• 2001

This study was conducted to derive the regional design rainfall by the regional frequency analysis based on the regionalization of the precipitation suggested by the first report of this project. Using the L-moment ratios and Kolmogorov-Smirnov test, the underlying regional probability distribution was identified to be the Generalized extreme value distribution among applied distributions. Regional and at-site parameters of the generalized extreme value distribution were estimated by the linear combination of the probability weighted moments, L-moment. The regional and at-site analysis for the design rainfall were tested by Monte Carlo simulation. Relative root-mean-square error(RRMSE), relative bias(RBIAS) and relative reduction(RR) in RRMSE were computed and compared with those resulting from at-site Monte Carlo simulation. All show that the regional analysis procedure can substantially reduce the RRMSE, RBIAS and RR in RRMSE in the prediction of design rainfall. Consequently, optimal design rainfalls following the legions and consecutive durations were derived by the regional frequency analysis.

• Journal of Korea Water Resources Association
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• v.37 no.12
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• pp.1019-1032
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• 2004

Flood frequency estimate is an essential index for determining the scale of small and middle hydraulic structure. However, this flood quantity could not be estimated directly for practical design purpose due to the lack of available flood data, and indirect method like design rainfall-runoff method have been used for the estimation of design flood. To give the good explain for design flood estimates, regional flood frequency analysis was performed by flood index method in this study. First, annual maximum series were constructed by using the collected data which covers from Japanese imperialism period to 1999. Wakeby distribution recommended by WMO(1989) was used for regional flood frequency analysis and L-moment method by Hosking (1990) was used for parameter estimation. For the homogeneity of region, the discordance and heterogeneity test by Hosking and Wallis(1993) was carried for 4 major watersheds in Korea. Physical independent variable correlated with index flood was watershed area. The relationship between specific discharge and watershed area showed a type of power function, i.e. the specific discharge decreases as watershed area increases. So flood quantity according to watershed area and return period was presented for each watershed(Han rivet, Nakdong river, Geum river and Youngsan/Seomjin river) by using this relation type. This result was also compared with the result of point frequency analysis and its regionalization. It was shown that the dam construction couldn't largely affect the variation of peak flood. The property of this study was also examined by comparison with previous studies.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.475-478
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• 2003

This study was conducted to compare the design rainfall derived by the at-site and regional frequency analysis based on the regionalization of the precipitation. The regional and at-site design rainfalls were calculated by Log-Pearson type III distribution using Indirect Methods of Moments(WRC). The regional and at-site analysis for the design rainfall were tested by Monte Carlo simulation. Relative root-mean-square error(RRMSE), Relative bias(RBIAS) and Relative reduction(RR) in RRMSE were computed and compared between design rainfalls resulted from observed and simulated data using the regional and at-site analysis. It was shown that the regional analysis procedure can substantially reduce the RRMSE, RBIAS in comparison with those of at-site analysis. Consequently, optimal design rainfalls following the regions and consecutive durations were derived by the regional frequency analysis.