8. Landforms of the Chad Basin

Lake Chad is the terminus of a vast inland drainage system. It was an inland sea with a basin connected to the sea through the River Mayo Kebbi. With time, fluvial processes cut off the sea by blocking its outlet, thereby turning it into the largest freshwater lake in the world, with a catchment area of 2,537,373 km² some 5000 years ago, ten times its present size. Since then, the water body area has reduced from 400,000 km² to between 1500 and 2000 km². This size reduction has been attributed mainly to anthropogenic activities and climate change. Other factors include a combination of desert winds blowing across portions of the basin that lie in the Sahara Desert and fluvial activities operating in more humid areas that lie within the Savanna belt. Lake Chad Basin has many landforms, including the grotesque-looking rock pedestals of the Ennedi Plateau along its northern boundary in Chad. They also include inselbergs in northern Nigeria, such as the famous Kano Dala Hill, the paleo-dunes that covered northern Jigawa and Yobe states of Nigeria, and the famous Bama Beach Ridge, which essentially forms a depositional ring of sand around the Mega-Chad. Man is a principal player in the Chad scenario; therefore, the study of the basin that is home to over 40 million people must include humans. For this reason, the socioeconomic implications of the dying lake are also briefly reviewed.