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
Castlereagh River travel the distance, and up to 47 hours. Usually in peak floods, the greater the water volume, the faster the travel times of the peak. However, the flattening of the terrain upstream of Coonamble results in decreased flow velocity (but means a greater area for the flow is needed to avoid flooding). It is not correct that the Castlereagh River is an underground river (subterranean river) or an 'upside down' river. However, water that once was in the river bed on the surface does flow through the extensive sands under the riverbed. This water is therefore part of the underground