A semi-artificial, eutrophic reservoir lying 15 km south-west of Homs and just west of Qattiné, formed by impoundment of the Nahr al-Asi (Orontes river). The banks of the north-eastern half are steep, while the very flat south-western shores, together with the influx of water from snow-melt in spring and subsequent evaporation during the summer, lead to the extent of open water varying from 3,000 ha in summer to 5,300 ha in winter; water depth is 4–8 m. There are some islands, but not suitable for breeding birds. The shores are generally bare mud, and the lake's marginal and aquatic vegetation is very limited; bankside vegetation includes Tamarix, Salix, Nerium, Phragmites and Typha. The surroundings are very open, with no trees of any size but still generally green and verdant. To the south the land is fertile and cultivated, but to the north is a large area of lava flow. Villages are scattered around the lakeside; the main human activity is farming, though there is considerable fishing, plus large factories near Qattiné.
See box for key species. More than 20,000 waterfowl occur in winter (e.g. 22,420 of 14 species in January 1993), including (counts mainly from the 1970s) Pelecanus onocrotalus (200), Egretta garzetta (100), Casmerodius albus (70), Anser albifrons (c.600), Anas crecca (4,000, October), A. strepera (c.700), Anas sp. (c.10,000), Netta rufina (250), Aythya ferina (7,000), Fulica atra (9,000) and unidentified waders (c.4,000). Counts of passage birds have included several hundred Chlidonias terns. Pelecanus onocrotalus, Egretta garzetta, Casmerodius albus and Porphyrio porphyrio have been recorded in the breeding season, but they are not likely to breed.
There is phosphate and urea pollution from factories near Qattiné, heavy shooting of wildfowl, much disturbance from recreational use (water sports), fishing and generally due to the high human population density. Pressure on fish stocks is very high; Common Carp Cyprinus carpio have been introduced. The lake was proposed as a Project Aqua conservation site by the Ministry of Agriculture and Agrarian Reform in the late 1960s.