Koka dam and Lake Gelila are on the Awash river in East Shewa Zone, 75 km south-east of Addis Ababa. The road to the dam is a 10-km track to the south of the main Mojo–Nazaret road. The shores of Lake Gelila can be reached via the Great Rift Valley road from Mojo to Meki, which passes over the Awash river about 20 km south of Mojo. Koka dam was built to provide hydroelectric power and came into operation in 1960. The resulting freshwater lake, Lake Gelila, has an area of c.180 km², and originally had a storage capacity of 1,850 million m3, although sedimentation has reduced this by 35%. The other main habitats are the surrounding farmland, an area of partly protected woodland beside the dam site, and the river and hot-spring area below the dam. Lake Gelila and its shoreline used to be fairly clear of vegetation, but Eichhornia crassipes has invaded the area and is spreading rapidly. As a result of crop cultivation the only large trees that are left in the area are figs, e.g. Ficus vasta and a few others generally associated with churches or other ceremonial places. The main activity in the area is farming and the most widely grown crop is Eragrostis tef. The farmers using the alluvial soil around the lake also grow horticultural crops and pulses, particularly haricot beans.
See Box for key species. Falco naumanni and Circus macrourus occur on spring and autumn passage, the latter fairly commonly. Numbers of Phoenicopterus minor fluctuate unpredictably. Several thousand Grus grus overwinter on the adjacent open plain and arable farmland. Acrocephalus griseldis was recorded regularly in small numbers between 1969 and 1976. Other species include Phoenicopterus ruber, Recurvirostra avosetta and Charadrius asiaticus. Larus cachinnans and L. ichthyaetus occur in small numbers, while tens of thousands of Motacilla flava and Hirundo rustica use the site. In addition, one species of the Sudan–Guinea Savanna biome has been recorded at this site (see Table 3).
Non-bird biodiversity: None known to BirdLife International.
Pressure/threats to key biodiversity
The greatest threat to Lake Koka itself is sedimentation. Recent studies show the rate of sedimentation to be 25 million m3 annually. The highly polluted Great and Little Akaki rivers are considered serious threats to the fisheries of Lake Gelila. Water from the Akaki river collects in the now-disused Abamuel reservoir and thus some of the pollutants may settle out before the water is discharged into the Awash river and then into Gelila. Over-fishing is an increasing problem. Hippopotamus amphibius, baboons and jackals are regarded as pests that damage crops. Grus grus is also seen as a serious pest as it arrives when crops are ripe and can strip fields of their grain. The people used to grow sorghum, but this has had to be abandoned because of the crane. Alopochen aegyptiacus is also a pest of cereals.
BirdLife International (2020) Important Bird Areas factsheet: Koka dam and Lake Gelila. Downloaded from
http://www.birdlife.org on 24/09/2020.