Huff의 4분위법을 이용한 지속기간별 연 최대치 강우의 시간분포 특성연구

이정규(Lee Jong-Kyu),추현재(Chu Hyun-Jae) 대한토목학회 2006 대한토목학회논문집 B Vol.26 No.5B

수공구조물 설계에서 가장 중요한 일은 설계홍수량을 결정하는 것이다. 따라서 설계홍수량 산정에 영향을 미치는 여러 가지 요소 중 적절한 설계 강우의 시간분포 방법을 선택하는 것은 중요한 일이다. 설계 강우의 시간분포 방법에는 여러 가지 방법 들이 있으며, 그 중에서 최근 첨두홍수량 산정을 위한 설계 강우의 시간분포 방법에 많이 이용하고 있는 Huff의 4분위법은 6시간 이상의 무강우시간을 갖는 강우시장을 자료로 이용, 분석하여 설계 강우의 시간분포 방법을 제시한 방법이다. 본 연구에서는 Huff의 4분위법에서 이용한 자료와 달리 1961년부터 2004년까지 서울지역 강우 관측자료 중 지속기간별 연 최대치 강우 자료를 이용하여 강우의 시간분포 특성을 분석하고 이전의 연구 결과와 비교하였다. 각각의 결과에 대하여 비교한 결과 서울지역의 경우 연 최대치 강우의 지속기간이 짧을 경우 무차원 누기곡선이 Huff의 4분위법 결과에 비하여 비교적 완만하게 나타났으며, 지속기간이 점점 증대될수록 무차원 누가곡선은 Huff의 4분위법 결과와 유사하게 나타났다. In the construction of hydraulic structures deciding a design flood is one of the most important works. It should be especially noted that the time distribution of the design rainfall method makes a significant effect on the results of the design flood. Thus, choosing an appropriate time distribution method for the design rainfall is a very important process. In recent years, Huff's method is usually used in Korea. This method presents dimensionless rainfall-time cumulative curves, which are made through the analyses of storm data. In this study, the annual maximum rainfall data, from 1961 to 2004 were analyzed to make the dimensionless rainfall-time cumulative curves and hyetographs in Seoul. The results were compared with the "Regional Time Distribution of the Design Rainfall", (KICT, 1989 and MCT, 2000). As a result, the dimensionless rainfall-time cumulative curves are smoother than Huff's results when the duration of an annual maximum rainfall is short, In addition, the curves are similar with the Huff's results as the duration is longer.

소규모 농업용저수지의 노후화에 따른 수문학적 안정성 검토

박기범(Ki-Bum Park) 한국환경관리학회 2017 環境管理學會誌 Vol.24 No.1

본 연구에서는 노후된 소규모 저수지에 대한 저수지의 홍수량을 산정하여 검토하였다. 전국에 40년 이상된 17,500개 이상이 분포하고 있다. 대부분의 노후된 저수지의 설계 당시 수문 데이터가 없으므로 현재의 설계기준에 대한 홍수 안정성에 대한 검토가 충분하지 않다. 확률 강우량을 분석 한 결과, 포항은 1966년 데이터의 두 배 이상 증가하였으며, 의성은 과거의 강우 자료와 비교하여 14% 감소한 것으로 분석되었다. 금회 산정한 홍수량 분석결과와 저수지 제원을 검토한 결과저수지의 여유고 부족과 홍수방어 측면에서 저수지의 위험성이 있는 것으로 판단되었으며, 노후된 저수지의 수문학적 안정성 검토가 시급히 이루어져야 할 것으로 판단된다. In this study, reservoir analysis was carried out for the aged small agricultural reservoir. More than 17,500 reservoirs over 40 years old are distributed nationwide. Most of the old reservoirs have no hydrological data at the time of designing, and the current design standards are not enough to control the flood. As a result of the analysis of the probability rainfall in this study, it was analyzed that Pohang was increased more than twice as much as the 1966 data. Uiseong has been reduced by 14% compared to past rainfall data. However, the flood volume is likely to be increased due to differences in analysis methods. In the present study, reservoir analysis of the flood reserves revealed that the present reservoir condition is very vulnerable to flooding. As a result of comparing the dam reserves considering the allowance, it is analyzed that the maximum dam reservoir should be increased by 1.79 m. The results of this study suggest that it is necessary to reevaluate the hydrological stability of many old reservoirs and to secure the flood stability of old reservoirs.

확률가중모벤트의 차수 변화에 따른 홍수량 변동 특성 분석

맹승진(Maeng, Seung-Jin),황주하(Hwang, Ju-Ha) 한국산학기술학회 2009 한국산학기술학회논문지 Vol.10 No.5

본 연구에서는 우리나라 수위관측소들 중에서 관측 유량이 검증된 총 19개 유역을 선정하고 관측된 홍수량을 사용하여 적정 설계홍수량을 유도함으로써 우리나라의 설계홍수량 특성을 분석하였다. 대상유역별로 관측개시년도에서 부터 분석 시작년을 기준으로 1년씩 증가 시키는 점진적 구성 방식으로 연최대홍수량에 대한 빈도분석을 실시하기 위해, 연강우량 변동특성을 이동평균법에 의해 분석하였다. 19개 대상유역에 대한 연최대홍수량 계열 구성 기간별로 기본통계치를 산정하고 독립성, 동질성 및 Outlier 검정을 실시하였다. Gumbel, Generalized Extreme Value, Generalized Logistic 및 Generalized Pareto 분포의 적합도 검정을 LH-모멘트비도와 Kolmogorov-Smimov 검정에 의해 수행하였다. 적정 확률분포로 선정된 GEV 분포의 매개변수를 확률가중모멘트의 차수 변화에 의한 L, L1, L2, L3 및 L4-모멘트법에 의해 추정하고 대상유역 및 연최대홍수량 계열 구성 기간별 설계홍수량을 유도하였다. 본 연구에서 사용한 변동률 분석에 따라 최근 지구온난화에 따른 우리니라 기후 변화를 고려한 적절한 수리구조물의 설계 조건 변경시기는 2002년 전후로 하여야 할 것 이다. In this research, various characteristics of South Korea's design flood have been examined by deriving appropriate design flood , using data obtained from careful observation of actual floods occurring in selected main watersheds of the nation. 19 watersheds were selected for research in Korea. The various characteristics of annual rainfall were analyzed by using a moving average metbod. The frequency analysis was decided to be performed on the annual maximum flood of succeeding one year as a reference year. For the 19 watersheds, tests of basic statistics, independent, homogeneity, and outlier were calculated per period of annual maximum flood series. By performing a test using the LH-moment ratio diagram and the Kolmogorov-Smirnov (K-S) test, among applied distributions of Gumbel (GUM), Generalized Extreme Value (GEV), Generalized Logistic (GLO) and Generalized Pareto (GPA) distribution was found to be adequate compared with other probability distributions. Parameters of GEV distribution were estimated by L, L1, L2, L3 and L4-moment method based on the change in the order of probability weighted moments. Design floods per watershed and the periods of annual maximum flood series were derived by GEV distribution. According to the result of the analysis performed by using variation rate used in this research, it has been concluded that the time for changing the design conditions to ensure the proper hydraulic structure that considers recent climate changes of the nation brought about by global warming should be around the year 2002.

3변수 및 4변수 Kappa 분포에 의한 설계홍수량 추정

맹승진,김병준,김형산,Maeng, Seung-Jin,Kim, Byeoung-Jun,Kim, Hyung-San 한국농공학회 2009 한국농공학회논문집 Vol.51 No.4

This paper is to induce design floods through L-moment with 3 and 4 parameter Kappa distributions including test of independence by Wald-Wolfowitz, homogeneity by Mann-Whitney and outlier by Grubbs-Beck on annual maximum flood flows at 9 water level gaging stations in Han, Nakdong and Geum Rivers of South Korea. After analyzing appropriateness of the data of annual maximum flood flows by Kolmogorov-Smirnov test, 3 and 4 Kappa distributions were applied and the appropriateness was judged. The parameters of 3 and 4 Kappa distributions were estimated by L-moment method and the design floods by water level gaging station was calculated. Through the comparative analysis using the relative root mean square errors (RRMSE) and relative absolute errors (RAE) calculated by 3 and 4 parameter Kappa distributions with 4 plotting position formulas, the result showed that the design floods by 4 parameter Kappa distribution with Weibull and Cunnane plotting position formulas are closer to the observed data than those obtained by 3 parameter Kappa distribution with 4 plotting position formulas and 4 parameter Kappa distribution with Hazen and Gringorten plotting position formulas.

Wakeby 및 Kappa 분포의 L-모멘트법에 의한 홍수빈도분석

맹승진,이순혁,이현규,류경식,송기현,Maeng, Seung-Jin,Lee, Soon-Hyuk,Lee, Hyeon-Gyu,Ryu, Kyong-Sik,Song, Gi-Heon 한국농공학회 2006 한국농공학회논문집 Vol.48 No.5

The objective of this study is to induce the design floods by the methodology of L-moment including test of homogeneity, independence and outlier of the data of annual maximum flood flows for 12 water level gaging stations of South Korea. To select appropriate distribution of the data for annual maximum flood flows, the distributions of Wakeby and Kappa are applied and the appropriateness is judged by Kolmogorov-smirnov (K-S) test. The parameters of selected Wakeby and Kappa distributions are calculated by the method of L-moment and the design floods are induced. Through the comparative analysis using the relative root mean square errors (RRMSE) and relative absolute errors (RAE) of design floods, the result shows that the design floods by Wakeby distribution are closer to the observed data than those obtained by the Kappa distribution.

기후변화에 따른 확률 일최대유량 산정(Ⅰ) - 유출분석을 중심으로 -

김형산,맹승진,황만하 위기관리 이론과 실천 2015 Crisisonomy Vol.11 No.5

최근 들어 우리나라는 지구온난화와 기후변화에 따른 극치수문사상의 발생 빈도 증가로 자연재해 횟수와 피해규모가 급증하고 있다. 자연재해 중 홍수에 의한 피해규모가 가장 크게 발생하고 있으며, 이를 예방하기 위해서는 기후변화에 따른 댐 및 수리구조물의 적정 설계홍수량 유도가 필요하다. 본 연구에서는 기후변화 시나리오를 반영한 일 단위 기반의 연최대홍수량을 산정하였으며, 다음 연구(2)에서는 미래 기후변화에 따른 확률 일최대유량의 변화를 분석하였다. 금강유역의 83개 강우관측소와 8개 기상관측소를 선정하여 과거 수문자료를 수집하였으며, RCP 시나리오의 일 강수량 및 온도자료를 2014년부터 2100년까지 추출하였다. 금강유역 주요지점의 기존 관측된 강수량과 유량자료를 일단위로 구성한 후 유출모형의 매개변수 검․보정을 실시하였다. 2006년과 2007년 모형의 보정 후 지점에 대한 상대오차의 평균은 10.5%, 9.2%로 나타났으며, 2004년 검증결과 9.2%로 나타났다. 최종적으로 결정된 매개변수를 이용하여 RCP 시나리오별 주요 지점의 연최대홍수량을 추출하였으며 확률 일최대유량 산정에 활용하고자 하였다. With the recent increase in frequency of extreme hydrological events due to global warming and climate change, the number of natural disasters especially by flood have rapidly increased in Korea. To prevent this damage, there is a need of proper flood flow designing for dams and hydraulic structures considering climate changes. In this study annual maximum daily streamflow was computed considering the climate change scenarios and in next study probable annual maximum daily streamflow was analyzed according to the future climate change. Past hydrological data was collected from 83 rainfall stations and 8 weather stations situated at Geum River watershed, temperature and daily precipitation data of the RCP scenarios was extracted from the year 2014 to 2100. Average relative error during the calibration of model at Geum river watershed for the year 2006 and 2007 was 10.5% and 9.2% respectively and verification result for 2004 was 9.2%. Finally, by using the determined parameters, annual maximum flood was computed at the main points corresponding to RCP scenarios that was further utilized for computation of probable annual maximum daily streamflow.

Multivariate design estimations under copulas constructions. Stage-1: Parametrical density constructions for defining flood marginals for the Kelantan River basin, Malaysia

Latif, Shahid,Mustafa, Firuza Techno-Press 2019 Ocean systems engineering Vol.9 No.3

Comprehensive understanding of the flood risk assessments via frequency analysis often demands multivariate designs under the different notations of return periods. Flood is a tri-variate random consequence, which often pointing the unreliability of univariate return period and demands for the joint dependency construction by accounting its multiple intercorrelated flood vectors i.e., flood peak, volume & durations. Selecting the most parsimonious probability functions for demonstrating univariate flood marginals distributions is often a mandatory pre-processing desire before the establishment of joint dependency. Especially under copulas methodology, which often allows the practitioner to model univariate marginals separately from their joint constructions. Parametric density approximations often hypothesized that the random samples must follow some specific or predefine probability density functions, which usually defines different estimates especially in the tail of distributions. Concentrations of the upper tail often seem interesting during flood modelling also, no evidence exhibited in favours of any fixed distributions, which often characterized through the trial and error procedure based on goodness-of-fit measures. On another side, model performance evaluations and selections of best-fitted distributions often demand precise investigations via comparing the relative sample reproducing capabilities otherwise, inconsistencies might reveal uncertainty. Also, the strength & weakness of different fitness statistics usually vary and having different extent during demonstrating gaps and dispensary among fitted distributions. In this literature, selections efforts of marginal distributions of flood variables are incorporated by employing an interactive set of parametric functions for event-based (or Block annual maxima) samples over the 50-years continuously-distributed streamflow characteristics for the Kelantan River basin at Gulliemard Bridge, Malaysia. Model fitness criteria are examined based on the degree of agreements between cumulative empirical and theoretical probabilities. Both the analytical as well as graphically visual inspections are undertaken to strengthen much decisive evidence in favour of best-fitted probability density.