Current view: Text account
Site description (2001 baseline):
Site location and context
Four large sewage-treatment lagoons, operational since late 1990, surrounded by grassland and
Acacia-dominated savanna, c.15 km north of Gaborone, close to the dormitory village of Phakalane. The lagoons are roughly rectangular (totalling 70 ha of water), generally steep-sided, and edged by high bunds. There are some exposed muddy edges, small areas of sand and gravel, several very small islands and remnants of dead and dying trees in one lagoon. There is marginal vegetation of
Typha,
Phragmites and scattered small trees and bushes.The site lies adjacent to the Ngotwane river, a small tributary of the Limpopo, into which the final effluent discharges. Riparian vegetation along this section of the Ngotwane is dominated by
Combretum and there are some open areas of wet grassland and
Juncus. Upriver in and south of Gaborone (outside the IBA) there are a series of artificial wetlands along the Ngotwane river. These are interlinked in that all are used by waterfowl which frequently move from one dam or sewage pond to another. These wetlands include Mogobane Dam, Ngotwane Dam, the large Gaborone Dam completed in 1964/65 and covering 19 km², various sewage ponds in Gaborone, notably Ngotwane, Maru-a-Pula and Tsholofelo, and associated wetlands such as the
Typha swamp in Gaborone Game Reserve. Although all these at times hold a diversity of waterfowl, none support large numbers nor any species in numbers that exceed the 0.5% threshold. Phakalane sewage ponds are undoubtedly the most important in this chain of wetlands.
See Box for key species. Phakalane lagoons support a wide diversity of visiting waders, wildfowl and other waterbirds, including both species of
Phoenicopterus. Although the total numbers are not exceptionally high, July 1994 saw nearly 1,600 waterbirds of 35 species and January 1995 over 3,000 birds of 36 species. Of particular note are the high numbers of
Oxyura maccoa, particularly in the winter (usually 100–200, but with a maximum of 440 recorded in July 1993). There are also regularly high numbers of
Netta erythrophthalma.Small numbers of some duck breed by the lagoons whilst waterbirds, notably
Threskiornis aethiopicus and
Bubulcus ibis, roost on dead trees. In the early years herons and egrets bred in the dead trees in the lagoons but the heronries have largely disappeared as these trees have died and fallen. The
Typha stands support large numbers of
Acrocephalus warblers. A roost of more than 50,000
Hirundo rustica occurs at Gaborone Dam, some birds also roosting at Phakalane.
Non-bird biodiversity: None known to BirdLife International.
Pressure/threats to key biodiversity
Access to the lagoons is restricted by Gaborone City Council, with permission given to the Botswana Bird Club and
bona fide birdwatchers for entry to carry out surveys and other ornithological work. Perimeter fences, in theory, keep out casual visitors and livestock, but gates are frequently vandalized or left unlocked, so there is open access to vehicles, quad-bikes, walkers, joggers, dogs and cattle. Limited grazing by cattle takes place; if unchecked this could disturb or damage the
Typha beds. Walkers and dogs, joggers and sports-clubs freely use the bunds, even the central bunds, for recreation, so causing disturbance to waterfowl. There is an intention by the City Council to draw up a management plan which might encourage quiet enjoyment of the area. It is vital in any such plan that people are kept away from the edges of the lagoons. There are opportunities to construct hides, to create nesting and roosting islands or rafts and to manage vegetation to maintain existing populations and to encourage other birds.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Phakalane sewage lagoons, near Gaborone (Botswana). Downloaded from
https://datazone.birdlife.org/site/factsheet/phakalane-sewage-lagoons-near-gaborone-iba-botswana on 23/11/2024.
