Cahora Bassa

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Cahora Bassa
A partial view of Cahora Bassa from space.
Coordinates	15°40′S 31°50′ECoordinates: 15°40′S 31°50′E
Lake type	Reservoir
Primary sources	Zambezi River
Primary outflows	Zambezi River
Catchment area	56,927 km²
Basin countries	Mozambique
Max length	250 km
Max width	38 km
Surface area	2,739 km²
Average depth	20.9 m
Max depth	157 m
Water volume	55.8 km³
Surface elevation	314 m

The Cahora Bassa lake is southern Africa's second-largest artificial lake, situated in the Tete Province in Mozambique. The name Cabora Bassa is also often seen, as this was used during the colonial period.

The Cahora Bassa Dam is one of the three major dams on the Zambezi river system, the others being Kariba and Itezhi-Tezhi. However, Itezhi-Tezhi is not on the main stream of the Zambezi, but on its tributary the Kafue River. The dam began to fill in December 1974 after construction was commenced in 1969 by the Portuguese colonial government, and is 171 m (560 feet) high by 303 m (994 feet) wide at the crest. The lake has reached a maximum length and width of approximately 250 km and 38 km respectively, flooding an area of 2,700 km² with an average depth of 20.9 m.

During its construction, the dam site was repeatedly attacking by Frelimo insurgents in an attempt to block what was at the time partially an attempt by Portugal to increase popular support for her colonial government in Mozambique (see Mozambican War of Independence). The dam was operated by Hidroelectrica de Cahora Bassa and jointly owned by Mozambique, with an 18% equity stake, and Portugal, which held the remaining 82% equity.

Since closure, the Zambezi, which is the fourth largest floodplain river in Africa, has received a far more regulated flow rate, but disastrous floods still occur. The 1978 flood caused 45 deaths, 100,000 people to be displaced and $62 million worth of damage. According to engineering consultants, "This was the first flood since completion of Cahora Bassa, and destroyed the widely held belief that the dam would finally bring flooding under full control".^[1] For further details of ecological problems caused by the dam, see the article on the Zambezi River.

A considerable kapenta fishery has developed in the dam. The kapenta is assumed to originate from Lake Kariba where it was introduced from Lake Tanganyika. Annual catch of kapenta in the Cahora Bassa dam in 2003 exceeded 10 thousand tons.

[edit] See also

Cabora-Bassa for details of the power scheme based on the dam.

[edit] References

^ Rendel, Palmer, and Tritton Consulting and Designing Engineers: "Review of the hydrological network, and study of the design of a flood warning system for the Zambezi River". Supplementary report. London: Institute of Hydrology, 1980. Quoted in Richard Beilfuss & David dos Santos: Patterns of Hydrological Change in the Zambezi Delta, Mozambique. Working Paper No 2 Program for the Sustainable Management of Cahora Bassa Dam and The Lower Zambezi Valley (2001)