The lake is located on the left bank of the Senegal River. It is the largest reserve of surface freshwater in the country. Embankments have been built at the northern and southern extremities. The lake is connected with the Senegal River by a canal. Its hydrological regime was submitted to the fluvial rising, but is now regulated by the dams constructed on the river.

Its principal uses are: irrigation for sugar cane and production of drinking water. In the future the lake could serve as starting point of a canal to Dakar (250 km) for supplying water the town. This shallow lake has a lot of similarities with Lake Chad, but its size permits an easier study of the ecosystem (Q).