Physiographic Features Guide
The Sahel is the semiarid region between the Sahara to the north and the savannas to the south, extending from Senegal to Ethiopia. The Sahel has natural pasture, with low-growing grass and tall trees. Forage for animals like camel, packed ox,grazing cattle, and sheep. At least 8 months of the year are dry, and rainfall averages 4 to 8 inches per year. So the Sahel forms a belt that separates the arid Sahara from tropical West Africa.
The Ethiopian Highlands are located on the western section of the Ethiopian Plateau. Fringed by the Sudan lowlands, these mountain are probably of early volcanic origin. The Ethiopian Plateau and several of its mountain groups are cut deep valleys. The Blue Nile runs from its source.
The Congo Basin is the worlds second-largest river basin, comprising an area of 1,335,000 square miles. The vast drainage area lies astride the Equator in west central Africa and includes almost all of Zaire, western Zambia, and northern Angola.