The rainfall Intensity-Duration-Frequency (IDF) relationship is widely used for adequate estimation of

rainfall intensity over a particular catchment. A 25 year daily rainfall data were collected from Nigerian

Meteorological Agency (NIMET) Abuja for Akure station. Twenty five year annual maximum rainfall

amounts with durations of 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240, 300 and 420 minutes were

extracted and subjected to frequency analysis using the excel solver software wizard. A total of six (6)

return period specific and one (1) general IDF models were developed for return periods of 2, 5, 10,

25, 50 and 100 years using Gumbel Extreme Value Type-1 and Log Pearson Type -3 distributions.

Anderson Darling goodness of fit test was used to ascertain the best fit probability distribution. The R2

values range from 0.982 to 0.985 for GEVT -1 and 0.978 to 0.989 for Log Pearson type -3 while the

Mean Squared Error from 33.56 to 156.50 for GEVT -1 and 43.01 to 150.63 Log Pearson Type III

distributions respectively. Among the six Geo-Political zones in Nigeria, the South – West of which

Akure is one of the cities is one of the least with IDF model development (16.7%). This is the basis of

IDF model development in Akure to help fill the gap. Is of interest to note that the South – East and

South – South have the highest percentage of IDF developed models (66.7%). The probability

distribution models are recommended for the prediction of rainfall intensities for Akure metropolis.

**Author(s) Details**

**Dr. A. O. David
**Department of Civil Engineering, Olabisi Onabanjo University, Ibogun Campus, Ogun State, Nigeria.

**Prof. Ify L. Nwaogazie
**Department of Civil and Environmental Engineering, University of Port Harcourt, Rivers State, Nigeria

**J. C. Agunwamba****
**Department of Civil Engineering, University of Nigeria, Nsukka, Enugu State, Nigeria.

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