Lake Chad

Lake Chad (Kanuri: Sádǝ, Lac Tchad) is a freshwater lake located at the junction of Nigeria, Niger, Chad and Cameroon in central and western Africa. It is also an important wetland ecosystem in West Africa. The catchment area of Lake Chad is 1 million square kilometers. It used to be a large lake with an area of 28,000 square kilometers in the 19th century. However, due to climate change and human water diversion, Lake Chad has been greatly reduced since the mid-1970s, and its area has fluctuated between 2,000 and 5,000 square kilometers. The Chad Basin was formed by the depression of the African Shield. The Chad Lake located in the center of the basin is the remnant of the Quaternary ancient Chad Sea. Its area experienced four heydays between 39,000 BC and 300 BC, leaving thick diatomaceous earth and lacustrine deposits in the strata. The largest area in history is about 340,400 square kilometers, the volume is about 13,500 cubic kilometers, the maximum depth is about 160 meters, and the lake is about 325 meters above sea level. It flows into the Benue River through the Mayo Kébbi, and finally flows into the Atlantic Ocean through the Niger River. The Chad Basin contains the earliest evidence of ancient human habitation found so far in West Africa. The Lake Chad area was settled as early as 500 BC, and major archaeological discoveries include the Sao civilization. According to the records of Claudius Ptolemy, the Roman general Septimius Flaccus led an expedition to the Sahara Desert in 50 AD, crossed the Tibesti Mountains, and reached the north of Lake Chad, known as "Hippo and Rhino Lake". The merchant Julius Maternus led an expedition through the same route around 83 AD and brought a rhino back to Rome from Lake Chad. Kingdoms arose around Lake Chad during the Middle Ages, and the Lake District became a refuge for tribes that refused to assimilate into these kingdoms. Lake Chad is recorded in many Arabic writings from the 9th to the 14th centuries due to the expansion of Islam into sub-Saharan Africa and the increased Arab interest in geographical exploration.