Abstract:
The objective of the study is to understand the rainfall variation in space and
time in the study area and analyze drought characteristics: intensity, duration,
frequency, severity. In this study, the differences in spatial patterns of drought
over a range of time scales were analyzed by the Standardized Precipitation
Index (SPl).Missing data were filled using Simple Average Method and Normal
ratio Method. Consistency or homogeneity were tested using SPLIT RECORD
TEST (F-test for stability of variance and t-test for stability of mean).Easy Fit
software was used for fitting the best distribution.
In this study, during the period investigated, the results show that the rainfall
decreased from 1989 but the decrease becomes stronger from 2000.ln this
period, the SPI for multiple scales under consideration namely 12 months (Jan
Dec), 8 months (Oct-May), 4 months (Oct-Jan), and 4 months (Feb-May) has
been computed for all selected stations. The relationship between rainfall
variability and drought event over the country was studied. The ratio is less than
25% and therefore, the variability is moderate in Burundi. Based on year 2005, it
was found that the eastern part region of Burundi has the highest coefficient
value (20%-32%) and the results show that there is a trend of SPI negative
values from the year 2000 up to 2005 for all selected stations in general and the
eastern part area in particular which implies that the eastern region of Burundi is
vulnerable to drought. In fact, the maximum duration (64 months) was recorded
at Giharo station, the maximum severity (8.43), maximum magnitude (0 . 19) and
maximum intensity (-3.57) were found at Kinyinya station). It appears that period
of drought have been quite frequent starting from 2000, with SPI ranging from
about -1 to about -3.
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