Abstract

A flood frequency analysis (FFA) of Gurara River catchments at Jere, Kaduna State, Nigeria, was carried out. Four probability distributions were used in the study namely, Extreme value type1, Normal, Exponential and Pearson type 3 distributions due to their desirable properties. The analysis was based on seventeen (17) years daily discharge data converted from gauge height readings. Partial duration series with a threshold of 273.95 m³/s, being the lowest annual maximum discharge of the 17 years annual peak flow was adapted for the FFA. A reduced variate principle was applied to fit a distribution to the generated data. Of the four probability distributions employed, Pearson type 3 distribution exhibited the best fit for the data.

Key words: Flood frequency analysis, recurrence interval, reduced variate, probability distribution.