Lac d’Aleg is situated 5 km to the north-west of the town of Aleg in the south-west of the country. The lake is a closed depression in an old course of the Senegal river fed by rainwater run-off from Oued Katchi, which drains a catchment of 3,420 km². The Katchi is a seasonal watercourse which was formerly a tributary of the Senegal river, but now cut off from it by dunes. The lake is endorheic and semi-permanent and typically varies in depth from 1–2 m at the end of the dry season to a maximum of 3–4 m at the end of the rains. At its maximum size, usually attained in October, it is 22 km long and 4 km wide. The area of the lake varies considerably from year to year depending on rainfall. The vegetetation of the lake forms concentric rings in which the central zone is characterized by Echinochloa stagnina, Nymphaea lotus, N. oleracea, Ipomoea aquatica and Aeschynomene pfundii. Nearer the water’s edge Sesbania rostata, Ammania senegalensis, Cynodon dactylon and Cyperus erectus dominate, while in seasonally inundated areas Bergia suffructicosa, Alternanthera sessilisa and Glinus lotoides are common. The banks are characterized by woody species such as Balanites aegyptiaca and Capparis decidua and grasses include Cenchrus biflorus, Cyperus conglomeratus and Dactyloctenium aegyptiacum. The southern edge of the lake is bounded by the Nouakchott–Aleg road. Average annual rainfall is c.150 mm.
See Box for key species. In addition, there are occasional records of Falco naumanni, Gallinago media, Glareola nordmanni and Acrocephalus paludicola from this site. All are thought to refer to birds on passage, although the status of A. paludicola is hard to establish. More than 116,000 waterbirds were recorded here in September 1987. Merops bulocki, a species of the Sudan–Guinea Savanna biome (A04), has been recorded at this site.
Non-bird biodiversity: None known to BirdLife International.
208734 individus répartis en 28 espèces ont été recensé en 2011 par la Direction des Aires Protégée et du Littoral(DAPL).
les espèces dominantes sont: Plectropterus gambensis(17500 individus), Dendrocygne viduata(32700 ind), Himantopus himantopus(13600),Anas querquedula(23800 ind), Porphyrio porphyrio(12000), Bubulcus ibis(9800ind) et Dendrocygne bicolor(9300ind).
en janvier 2017,41600 individus ont été compté avec 24 espèces différentes(den Natmau, 2017).
les espèces dominantes sont: Anas querquedula( 12500individus),Plectropterus gambensis(6500 ind), Dendrocygna viduata(6580) et Himantopus himantopus(7550)
BirdLife International (2020) Important Bird Areas factsheet: Lac d'Aleg. Downloaded from http://www.birdlife.org on 09/07/2020.