EVALUATING DROUGHTS IN OROMIA REGIONAL STATE OF ETHIOPIA FOR BETTER PREPARDNESS

Abstract

The Oromia regional state is significantly vulnerable to the impacts of drought. Majority of the population of the region is involved in agricultural and pastoral activities for their livelihood. The agriculture is predominantly dependent on the right onset, quantity, period, and distribution of natural rainfall. Though there is abundant water source over the region, the region utilized only 5% of the irrigated land to produce agricultural products. This makes the region susceptible to impacts of climatic extreme events such as drought. Yet, no drought assessment studies have been conducted on spatial and temporal analysis of recent droughts over Oromia. In view of that, this study examined the spatial and temporal characteristics of drought in the period 1989 to 2019 over Oromia regional state of Ethiopia using Standardized Precipitation and Evapotranspiration (SPEI) and Standardized Precipitation Index (SPI) drought indices. Temporal trends of drought over the study area were assessed using Man-Kendal trend test. The study also assessed the role of El Niño-Southern Oscillation in inducing seasonal droughts. The results of this study showed that drought occurrences demonstrated complex patterns over the region b oth spatially and temporally. The drought incidences at each of the stations had diverse magnitudes and durations. During belg, seasonal drought was more frequent over the southern and eastern regions of Oromia whereas less frequent over the western and central regions. The spatial coverage of belg droughts increased over the study area since the year 1997 and decreased in recent years, particularly since 2016. During kiremt, seasonal drought was more frequent over western regions of Oromia whereas less frequent over southern and eastern regions. The year 2002 was found to be the driest year with significant regions of the study area had considerable extreme and severe kiremt droughts. The years 2002, 2015, 2000, 2009 and 1991 (ordered from high to low spatial coverage) were among the major hydrological drought years over the study area; with at least 34% of the study area had annual droughts. There were 26 stations that showed increasing dry tendencies and 28 stations that showed wetting tendencies. The association between El Niño-Southern Oscillation and seasonal drought over the regions was found to beprospective.