It has been designated a Wetland of International Importance under the Ramsar Convention.

The normal size of the lake is about 50,000 ha (120,000 acres), though this can triple in wetter years.

It is fed by seasonal rainfall and run-off from a catchment area estimated at 70,000 km2 (27,000 sq mi).

The normally permanent lake may dry out during severe drought periods, such as occurred at the beginning of the twentieth century and again in 1984–1985.

The lake has been designated an Important Bird Area (IBA) by BirdLife International because it supports significant populations of white-faced and fulvous whistling-ducks, ferruginous ducks, garganeys, northern pintails, black crowned cranes, African spoonbills and squacco herons.