The remnant of a large ancient sea, Lake Chad has existed for thousands of years.
The countries of Chad, Cameroon, Nigeria, and Niger all have shorelines on Lake Chad. In modern times the lake has fluctuated seasonally, depending on rainfall that supplies its major tributaries, the Komadougou-Yobe and Chari rivers. It has shrunk from its largest, 154,400 square miles to less than 1,000 square miles. This is partly the result of a series of droughts and partly the result of water being drained from the Chari and other tributary rivers and the lake itself to be used for irrigation of crops. The majority of the remaining water is in Chad and Cameroon. Lake Chad is very shallow and has no outlet. Its Despite these changes the lake is still one of Africa’s largest, and it is a major source of freshwater for millions of people.
Petroleum reserves have been discovered in Chad and Niger. Natron (hydrated sodium carbonate), found in depressions along the northeastern shore of the lake, has long been economically important. Traditionally, it is excavated in blocks and shipped across the lake, where it enters Nigerian commerce.
Alabama Virtual Library, Britannica School