In the Zambezi basin, there are a number of major rivers flowing wholly or partially through Zambia: the Kabompo, Lungwebungu, Kafue, Luangwa, and the Zambezi itself, which flows through the country in the west and then forms its southern border with Namibia, Botswana and Zimbabwe. Its source is in Zambia but it diverts into Angola, and a number of its tributaries rise in Angola's central highlands. The edge of the Cuando River floodplain (not its main channel) forms Zambia's southwestern border, and via the Chobe River that river contributes very little water to the Zambezi because most are lost by evaporation.