Lake Guiers and Senegal and Ferlo Rivers, Senegal and Mauritania16.4N 15.6W
Flowing horizontally across the top of this orthorectified wide-swath ASAR image is the Sénégal River, is a 1,790 km (1,110 mi) long river in West Africa that forms the border between Senegal and Mauritania. The river has a drainage basin of 483,181 km2 (186,557 sq mi), a mean flow of 640 cubic metres per second (23,000 cu ft/s) at its mouth, and an estimated annual discharge of 20,000 cubic hectometers.
The dark grey area near the left edge is the Lac de Guiers or Lake Guiers, a lake in northern Senegal, south of the city of Richard-Toll and in the Louga and Saint-Louis regions. 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 Water used to flow out to the Senegal River north through the Portuguese River, but this has been replaced by a straight canal to Richard-Toll.