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 emptied eastwards. The Upper Zambezi was captured as well. The Middle Zambezi was about lower than the Upper Zambezi, and a high waterfall formed at the edge of the basalt plateau across which the upper river flows. This was the first Victoria Falls, somewhere down the Batoka Gorge near where Lake Kariba is now. The first European to come across the Zambezi river was Vasco da Gama, in January 1498, who anchored at what he called "Rio dos Bons Sinais" ("River of Good Omens"), now the Quelimane or Quá-Qua, a small river on the northern end of the delta, which