Abstract:
Rainfall of a place can be completely defined if the intensities, durations and
frequencies of the various storms occurring at that place are known. Intensity
Duration-Frequency (IDF) relationship is one of the most commonly used tools
which provide essential information for planning, designing and operation of
water resource projects. Therefore, the main purpose of this research work was
to develop operational IDF relationships for Amhara and Tigray regional states
based on thirty three first class stations.
Rainfall charts of different years were used to collect annual maximum rainfall
depths of varying durations. The best fitted probability distributions are selected
for all the principal stations and based on these distributions quantiles are
estimated. With the help of the general mathematical forms of IDF, IDF-Curves
and IDF-Maps intensities of each station were determined.
Amhara and Tigray regional states have been regionalized and five different
regions were established based on pooled quantiles of the 24-hour durations.
And the regionalization is used for the determination of intensity of rainfall for
areas farthest from the principal stations.
IDF relationship being an important hydrologic tool it helps to fill the gap
between the design need and the unavailability of design information. Therefore,
