Abstract:
Genale-Dawa Basin is the third largest basin in Ethiopia in its area coverage. It has a basin
area of 172681 square kilometres. The study area is mainly limited to the northern part of the
basin in which the highlands of Sidamo and Bale are included. This area gets relatively
ample amount of annual rainfall as compared to other areas of the same basin.
In the study 21 micro hydropower sites were identified. All of them are found in the
aforementioned northern part because of the dependable annual flow as a result of adequate
rainfall in the southeast.
All of the identified sites except one are unguaged. Therefore the discharges of these sites
were transferred from the nearby gauged rivers by area-ratio method. There are about 30
gauging stations· in the basin. However, only four of them have full data for the duration
under consideration. In order to come up with reasonable result for water-related studies, a
data of at least 15 to 20 years is needed. Stream flow data of 19 years were analysed during
the study. Prior to transfer of discharges to the identified river sites, filling and extension of
the missing data was carried out. The catchment areas of the identified sites were determined from topographic map of scale
1 :50,000. The gauged rivers which have comparable catchment area and which are found in
similar natural features were used for the transfer of stream flow.
Having finished the process of transfer of stream flow, the potential hydropower and energy
of the identified river sites were estimated. Two methods were used for this computation.
These were the flow duration curve and the monthly flow. The total annual power and energy
output of all sites as estimated by FDC were found to be 49,248.86kW and 44.633GWh/year
respectively. The computation carried out by using the monthly flow shows that the total
potential power and energy output from all sites were 81,927.58kW and 59.807GWh/year
