New publication: Watersheds of the World: Africa - Nile Watershed

In the publication, Watersheds of the World (Revenga, et al., 1998), a watershed or river basin is defined as the entire area drained by a major river system or by one of its main tributaries. Often extending across one or more international boundaries, watersheds play a critical role in the natural functioning of the Earth. Watersheds used in Watersheds of the World were modeled from elevation data using Geographic Information Systems (GIS) software. Each watershed map presents the area occupied by the basin, the number of cities with a population greater than 100,000 people, the number of Ramsar sites (sites of wetlands of international importance) and the extent of modified landscape within the basin.