독립 호우사상의 빈도해석 및 유출해석 = Frequency analysis of independent rainfall events and runoff analysis

다국어 초록 (Multilingual Abstract)

This study performed the bivariate frequency analysis and runoff analysis using the independent rainfall events, which were compared to the results by conventional method. Firstly, This study investigated the characteristics of independent rainfall events decided by applying various separation criteria to the hourly rainfall data in Seoul for the duration from 1961 to 2010. Secondly, This study investigated the method suggested to decide the annual maximum independent rainfall event and decided the annual maximum independent rainfall series through this method. Rainfall events in various durations satisfying with the specific return period were decided by bivariate frequency analysis on the annual maximum rainfall series. Lastly, flood discharges were calculated in the Jungrang-cheon, Cheonggye-cheon and Ui-cheon basins by using Clark model with the results of bivariate frequency analysis. The flood discharges were compared to the ones calculated from the conventional method. the results of this study are as follows.
First, the effect of IETD and threshold was not beyond the expected level. For example, as the IETD increases, the frequencies of independent rainfall events decreased similarly in their rate for both with short and long durations. However, as the threshold increases, The frequency of those with rather long durations decreased much higher. The mean rainfall intensity of the independent rainfall events was found to remain constant regardless of their duration. This indicates that the annual maximum rainfall intensity could be found in a rainfall event with longer durations.
Second, when applying the method of moments for the parameter estimation, it was found necessary to consider the correlation coefficient between the two variables as well as the mean and variance. The method of maximum likelihood was better to reproduce the mean, but the method of moments was better to reproduce the annual variation of the variance. The annual maximum rainfall events derived were very similar in both cases.
The difference between the bivariate design rainfall and the univariate design rainfall was found to be different with respect to rainfall duration. The difference with rather short rainfall duration was found significantly large, which decreases with longer durations. Univariate design rainfall with short rainfall duration are larger than bivariate design rainfall. However these results were found to be reversed with increase of rainfall duration.
In the case of applying Huff method, the flood discharge of Jungrang-cheon basin calculated by applying the bivariate design rainfall was found to be larger than that of applying the univariate design rainfall. On the other hand, this result was found to be reversed in the case of Cheonggye-cheon and Ui-cheon basin. However this results were found to be caused by influence of short time of concentration, storage coefficient and large CN value. In the case of applying alternative block method, the flood discharges of all watersheds calculated by applying the bivariate design rainfall was found to be larger than that of applying the univariate design rainfall. This result indicates that the flood discharge from the conventional method could be underestimated compared to the really possible flood discharge.

목차 (Table of Contents)

• 제 1 장 서 론 1
• 제 2 장 이론적 배경 4
• 2.1 독립 호우사상의 결정 4
• 2.1.1 IETD의 영향 4
• 2.1.2 절단값의 영향 5
• 2.2 연최대치 독립 호우사상의 결정 6
• 2.2.1 Freund 이변량 지수분포 모형 6
• 2.2.2 독립 호우사상의 재현기간 산정방법 11
• 2.3 연최대치 독립 호우사상의 이변량 빈도해석 13
• 2.3.1 Gumbel 로지스틱 모형 14
• 2.3.2 이변량 빈도해석에의 재현기간 산정방법 16
• 제 3 장 대상 자료 20
• 제 4 장 독립 호우사상의 결정 21
• 4.1 IETD 및 절단값에 따른 독립 호우사상의 구성 및 특성 분석 21
• 4.1.1 독립 호우사상의 구성 21
• 4.1.2 독립 호우사상의 발생빈도 특성 24
• 4.1.3 독립 호우사상의 평균 강우강도 특성 26
• 4.2 대표 독립 호우사상의 결정 29
• 4.2.1 대표 IETD 및 절단값의 결정 29
• 4.2.2 결정된 전체 독립 호우사상의 특성 30
• 4.2.3 1961년 사례 분석 32
• 제 5 장 연최대치 독립 호우사상 계열의 결정 33
• 5.1 Fruend 이변량 지수분포의 매개변수 추정방법 검토 34
• 5.1.1 모멘트법을 이용한 매개변수 추정 34
• 5.1.2 최우도법을 이용한 매개변수 추정 38
• 5.2 연최대치 독립 호우사상 계열의 결정 40
• 제 6 장 연최대치 독립 호우사상 계열의 이변량 빈도해석 43
• 6.1 적합도 검토 및 매개변수 추정 43
• 6.2 이변량 빈도해석 방법의 적용 결과 44
• 제 7 장 단변량 및 이변량 설계강우의 유출해석 결과 비교 48
• 7.1 유출모형과 강우 시간분포 방법에 대한 영향 검토 48
• 7.1.1 유출모형의 매개변수에 대한 영향 검토 48
• 7.1.2 시간분포 방법에 대한 영향 검토 57
• 7.2 실제 유역에의 적용 61
• 7.2.1 대상유역 61
• 7.2.2 유출모형의 매개변수 추정 및 유효우량 산정방법의 선정 65
• 7.2.3 적용 결과 비교 67
• 제 8 장 결론 77
• 제 9 장 참고문헌 80