Lake Volta is a large reservoir contained behind the Akosombo Dam. It is completely within the country of Ghana and has a surface area of 8,502 square kilometres (3,283 sq mi). Lake Volta is located completely within Ghana, West Africa. Lake Volta is the largest man-made lake in the world with a surface area of 3,275 square miles.Lake Volta is contained behind the Akosombo Dam, which provides electricity for the country of Ghana.
Source: http://www.touchalifekids.org/wp-content/uploads/2014/09/LakeVolta_Facts.pdf, https://en.wikipedia.org/wiki/Lake_Volta