The Akaki–Aba-Samuel wetlands are part of the Awash river catchment, c.20 km south-east of Addis Ababa. The wetlands consist of Aba-Samuel reservoir and an adjacent area that is inundated most of the year. The Akaki river consists of two main branches, the confluence of which is at the Aba-Samuel reservoir. The western branch of the river rises north-west of Addis Ababa on the flanks of Wechacha mountain and flows for c.40 km before it reaches the reservoir. The eastern branch of the river rises north-east of Addis Ababa and flows into Aba-Samuel reservoir after c.53 km. The reservoir was created in 1939 to produce electricity for Addis Ababa, and production continued until 1970 when the machinery became too old to maintain and the plant stopped working. Aba-Samuel reservoir catchment area is 1,495 km², and includes the catchment of the Lege Dadi dam. The reservoir originally had an area of 12,068 km², but the catchment has suffered much erosion resulting in silt deposition in the reservoir that has also been invaded by Eichhornia crassipes. Both of these factors have severely reduced the area of open water. The area around Akaki–Aba-Samuel is permanently marshy with small ephemeral lakes. The fringe of the marsh has some tall sedges, grasses and reeds. The rest of the area is farmland and grassland with a few scattered trees, mostly Faidherbia albida and figs.
See Box for key species. Akaki is important for wintering waterbirds, over 20,000 occasionally being present, with high numbers noted for Philomachus pugnax (max. 3,671), Anas clypeata (max. 1,119) and Phoenicopterus minor (1,750). Resident waterbirds occurring in numbers include Pelecanus onocrotalus, Mycteria ibis, Phoenicopterus ruber, Alopochen aegyptiacus, Anas undulata, Himantopus himantopus and Vanellus spinosus. Balearica pavonina also occurs at Akaki, and Eupodotis melanogaster can occasionally be seen in the area, particularly from May to July. Globally threatened species include Crex crex (rare), Aquila clanga (rare), Falco naumanni (present in small numbers on passage, with a few possibly overwintering) and Grus carunculatus (present occasionally, in small numbers). At least seven Afrotropical Highlands biome species are known to occur at Akaki. However, the most important species is Grus grus, which has a wintering population that uses the area for roosting and feeding, especially from November to late February/March. Up to 8,600 individuals have been recorded at Akaki. The population of G. grus is not limited to the Akaki lakes: other substantial numbers occur in the Debre Zeit and Koka lake areas. These probably form part of the same population as is found at Akaki, with birds foraging on post-harvest crop stubble as far away as Melka Konture and Bu-i to the west, Koka lake in the south, and north/north-east of Debre Zeit.
Non-bird biodiversity: None known to BirdLife International.
BirdLife International (2019) Important Bird Areas factsheet: Akaki - Aba-Samuel wetlands. Downloaded from http://www.birdlife.org on 06/12/2019.