Senegal River and Lac de Guiers, Senegal and Mauritania16.2N 15.8W
The Senegal River, flowing more or less horizontally across the image, marks the border between Mauritania (above) and Senegal (below). On a vertical axis near the image center is a lake whose waters appear green: the Lac de Guiers.
The lake is located in northern Senegal, south of the city of Richard-Toll and in the Louga and Saint-Louis regions. It is a chief source of fresh water for the city of Dakar, hundreds of kilometers to the south-west, through underground pipes.
It is about 35 kilometers long and 8 kilometers wide, and is supplied by the Ferlo or Bounoum River, which flows north into its southern end from Fouta in the rainy season. Water used to flow out to the Senegal River north through the Portuguese River, but this has been replaced by a straight canal to Richard-Toll. A dam was built in 1916 to prevent saltwater flowing in from Taoué River and the Senegal River Delta.
The shores are mostly fertile. The north shore and surrounding area have been converted to a large sugar-growing region irrigated with water from the lake. Lac de Guiers is also designated an Important Bird Area by BirdLife International.