Luangwa River ago, there was no way out and the Luangwa Rift filled with a Rift Valley Lake called the Madumabisa Lake, which rivalled Lake Malawi in size. The water of the lake overflowed in a river to the south-west, towards what is now the Kalahari, where it combined with the Okavango, Upper Zambezi, Cuando and Kafue rivers, emptying into the Limpopo River and flowing to the Indian Ocean. Several geological events combined to produce the current river systems. Faulting produced another graben just to the south of the Luangwa Rift, and running east-west: the Zambezi Rift Valley and the Chicoa Trough.
Zambezi the Ikelenge District of North-Western Province, Zambia at about above sea level. The area around the source is a national monument, forest reserve and Important Bird Area. Eastward of the source, the watershed between the Congo and Zambezi basins is a well-marked belt of high ground, running nearly east-west and falling abruptly to the north and south. This distinctly cuts off the basin of the Lualaba (the main branch of the upper Congo) from that of the Zambezi. In the neighborhood of the source the watershed is not as clearly defined, but the two river systems do not connect. The