BEST-FIT DISTRIBUTIONS FOR ANNUAL FLOOD PEAKS

Abstract

The estimation of flood magnitudes of desired return periods'san important problem in water resources engineering. For this, a frequency analysis of the observed flood peaks is carried out wherein a theoretical probability distri-bu-tion is fitted to the available data to estimate the floods of desired to return periods. Many probability distribu- tions have been found to be useful for hydrologic fre=. quency analysis. However, there is a need to determine the proper distribution function that fits best the observed flood data. This study is directed towards it, and aims at presenting the methology to determine the best distributions for among several commonly used distributions like Normal, Log-Normal, Extreme value I, and Log Pearson III. It has been attempted by first carrying out a literature survey to understand and present the characteritics of the various probability distributions, and then develop several computer programs to test the distributions...