MODELLING OF SHORT DURATION RAINFALL (SDR) INTENSITY EQUATIONS FOR ERZURUM

The scope of this study is to develop a rainfall intensity-duration-frequency (IDF) equation for some return periods at Erzurum rainfall station. The maximum annual rainfall values for 5, 10, 15, 30 and 60 minutes are statistically analyzed for the period 1956 - 2004 by using some statistical distributions such as the Generalized Extreme Values (GEV), Gumbel, Normal, Two-parameter Lognormal, Three-parameter Lognormal, Gamma, Pearson type III and Log-Pearson type III distributions. chi(2) goodness-of-fit test was used to choose the best statistical distribution among all distributions. IDF equation constants and coefficients of correlation (R) for each emprical functions are calculated using nonlinear estimation method for each return periods (T = 2, 5, 10, 25, 50, 75 and 100 years). The most suitable IDF equation is observed that i(max) (t) = A / (t + C)(B), except for T=100 years, because of the highest coefficients of correlation.