The existence of this lake called the "Great Lake" in the inner delta of Niger River between Jenne and Timbuktu in Mali has been established after extensive study of maps of the region extending over a period from 1000 to 1900 AD; 400 maps were studied for the period.

[7] Geological formations recorded at the bed of the lake are "from dense crystalline rock of Precambrian sandstone compacted in the broad Taoudeni Syncline as an alluvial fan and covered by a hard layer of cemented-laterite."

[1] It is integral to the wide river channel with its size fluctuating with variation of the water level in the lake.

Foolahs, the nomads who live here, use these marshes as pastures in the dry season and thereafter they go back to their habitats in the interior of the basin.

The rainy season in the south lasts from July to October, with an average annual rainfall of 750 mm (30 in).

However, the rainy season in the north lasts from July to September, with an average annual precipitation recorded at 250 mm (9.8 in).

The cooler climatic season is from December to January with temperatures dropping to a mean minimum of 3 °C (37 °F) to 6 °C (43 °F) in the northern part of the delta.

Another plant species that acts as barrier to sand deposition is the Vetiveria nigritiana, when the water stages in the lake and the delta is high.

The aquatic plants sustain varying levels of water in the lake and the soil types dictates the ecology of the region.

[17] Akkagoun and Dentaka are the forested areas surrounding the lake and the delta, which are home for many water birds.

[14] The West African manatee is the most prominent fauna species in the lake which is reported as its last habitat in the world.

[18] The avifauna found within the lake area, which forms one of the major wetlands in the Sahel, is represented by species from both the Palearctic and Afrotropic ecozones.

Over one million birds have been recorded as using the lake;,[10] including a large number of migratory and resident species, such as sand martin and yellow wagtail, reed cormorant, glossy ibis, spoonbill, great white egret, purple heron, ferruginous duck, white-winged black tern, ruff and black-tailed godwit.

[18] A sea side feeling is felt around the lake and the delta, as the air is filled with the sounds of water birds and gulls.

[4][19] The Synodontis gobroni and the Gobiocichla wonderi are two endemic species of fishes in the lake which is part of the inland delta.