**2.2 Historical drought in Ethiopia**

Ethiopia is experienced severe drought problems for the last decades. According to Mohammed et al., the most drought years in North East Highlands of Ethiopia were 1984, 1987, 1988, 1992, 1993, 1999, 2003, 2004, 2007, and 2008 [1]. Bayissa et al. also found that 1984/85 and 2003/04 were the extreme drought years in the Upper Blue Nile basin in Ethiopia [29]. Based on EM-DAT, 2014, the most severe drought years in Ethiopia from 1900 to 2013 were 1965, 1969, 1973, 1983, 1987, 1989, 1997, 1998, 1999, 2003, 2005, 2008, 2009, and 2012 with an average recurrence interval of 4 years

**Figure 2.** *Seasonal variation of streamflow over Ethiopian river basins.*

## **Figure 3.**

*Mean monthly rainfall of eight river basins in Ethiopia.*



**Table 2.**

*Summary of selected literature related to drought studies in Ethiopia for this review.*

[30]. Generally, the year 1984 was a bad drought event in Ethiopia and it was globally known. Here, all the above-stated drought years were analyzed based on meteorological drought indicators, especially standardized precipitation index (SPI) and palm drought severity index (PDSI).
