Figure 3 Upper Awash basin mean rainfall since 1991 to 2015
Midland area stations (Sebata,
Kimoye, and Ginchi, Asgori) revealed seasonal decrease with
precipitation except Asgori is increasing in the Birraa season.
So, it is possible to say all stations resulted in a decreasing trend of
seasonal precipitation in 25 years of study time series. These stations
increased with maximum temperature at Kimoye and Asgori stations while
decreasing trend resulted from Sebata and Ginchi stations. The annual
and seasonal precipitation trend of Sebata station is significantly
increasing. Moreover, except Bona season of Kimoye andGanna season of Asgori, annual and seasonal trends of temperature
significantly increase at 0.1 critical value. But Ginchi and Sebata
stations are insignificantly decreased trend with maximum temperature.
Precipitation of Highland area stations (Addis Ababa, Sendafa, Ejere,
and Addis Alem) exhibited a decreasing trend annually and inArfaasaa seasons except Sendafa station got an increasing trend.
Addis Alem decreased Annually at a 95% significance level while other
stations are statistically insignificant. During Ganna season,
Addis Alem and Addis Ababa stations increased insignificantly while
Sendafa station significantly increased. Contrarily, Ejere stations
significantly decreased at 0.05 critical value. Highland stations
exhibited an annually decreasing trend except for Sendafa station.