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.
View Book :- https://bp.bookpi.org/index.php/bpi/catalog/book/247
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