EstimatingT‐year flood confidence intervals of rivers inÇoruh basin,Turkey

Abstract

AbstractThe aim of this study is to determine the most suitable probability distribution for estimatingT‐year flood confidence intervals of the rivers inÇoruh basin,Turkey. For this purpose, 10 different distributions, which are widely used in hydrologic frequency analysis, were fitted to annual maximum flows of nine gauging stations located in critical parts of the basin, and parameters of these distributions were estimated using the method of maximum likelihood. In order to determine the most suitable distributions at each station,Akaike's information criterion, modifiedAkaike's information criterion,Bayesian information criterion,Kolmogorov–Smirnov and chi‐square goodness‐of‐fit tests were applied. According to evaluations of these tests, two‐parameter lognormal,Gumbel and generalised Pareto appeared to be the most suitable distributions. Then, these distributions were used for the estimation ofT‐year's flood confidence intervals (10, 20, 50, 100 and 200 years). Finally, the performances of the distributions were compared and discussed with regard to its application on the stations.