<P> The major drainage divide runs from the southwest part of the Akwapim - Togo Ranges northwest through the Kwahu Plateau and then irregularly westward to the Ivory Coast border . Almost all the rivers and streams north of this divide form part of the Volta system . Extending about 1,600 kilometers in length and draining an area of about 388,000 square kilometers, of which about 158,000 km lie within Ghana, the Volta and its tributaries, such as the Afram River and the Oti River, drain more than two thirds of Ghana . To the south of the divide are several smaller, independent rivers . The most important of these are the Pra River, the Tano River, the Ankobra River, the Birim River, and the Densu River . With the exception of smaller streams that dry up in the dry seasons or rivers that empty into inland lakes, all the major rivers in Ghana flow into the Gulf of Guinea directly or as tributaries to other major rivers . The Ankobra and Tano are navigable for considerable distances in their lower reaches . </P> <P> Navigation on the Volta River has changed significantly since 1964 . Construction of the dam at Akosombo, about 80 kilometers upstream from the coast, created the vast Lake Volta and the associated 1020 megawatt hydroelectric project . Arms of the lake extended into the lower - lying areas, forcing the relocation of 78,000 people to newly created townships on the lake's higher banks . The Black Volta River and the White Volta River flow separately into the lake . Before their confluence was submerged, the rivers came together in the middle of Ghana to form the main Volta River . </P> <P> The Oti River and the Daka River, the principal tributaries of the Volta in the eastern part of Ghana, and the Pru River, the Sene River, and the Afram River, major tributaries to the north of the Kawhu Plateau, also empty into flooded extensions of the lake in their river valleys . Lake Volta is a rich source of fish, and its potential as a source for irrigation is reflected in an agricultural mechanization agreement signed in the late 1980s to irrigate the Afram Plains . The lake is navigable from Akosombo through Yeji in the middle of Ghana . A 24 - meter pontoon was commissioned in 1989 to link the Afram Plains to the west of the lake with the lower Volta region to the east . Hydroelectricity generated from Akosombo supplies Ghana, Togo, and Benin . </P> <P> On the other side of the Kwahu Plateau from Lake Volta are several river systems, including the Pra, Ankobra, Tano and Densu . The Pra is the easternmost and the largest of the three principal rivers that drain the area south of the Volta divide . Rising south of the Kwahu Plateau and flowing southward, the Pra enters the Gulf of Guinea east of Takoradi . In the early part of the twentieth century, the Pra was used extensively to float timber to the coast for export . This trade is now carried by road and rail transportation . </P>

What percentage of ghana is covered by water