Zambezi the overflow of the Zambezi in the rainy season. The delta of the Zambezi is today about half as broad as it was before the construction of the Kariba and Cahora Bassa dams controlled the seasonal variations in the flow rate of the river. Before the dams were built seasonal flooding of the Zambezi had quite a different impact on the ecosystems of the delta from today as it brought nutritious fresh water down to the Indian Ocean coastal wetlands. The lower Zambezi experienced a small flood surge early in the dry season as rain in the Gwembe catchment and
Zambezi tributary of the Shire River in the East African Rift's southern extension through Malawi eroded a deep valley on its western escarpment. At the rate of a few cm per year, this river, the Middle Zambezi, started cutting back the bed of its river towards the west, aided by grabens (rift valleys) forming along its course in an east-west axis. As it did so it captured a number of south-flowing rivers such as the Luangwa and Kafue. Eventually the large lake trapped at Makgadikgadi (or a tributary of it) was captured by the Middle Zambezi cutting back towards it, and