Kariba dam
| Kariba dam | |||||||||||
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| Coordinates | 16 ° 31 ′ 21 ″ S , 28 ° 45 ′ 42 ″ E | ||||||||||
| Data on the structure | |||||||||||
| Construction time: | 1955 to 1959 | ||||||||||
| Height of the barrier structure : | 128 m | ||||||||||
| Building volume: | 1 032 000 m³ | ||||||||||
| Crown length: | 617 m | ||||||||||
| Base width: | 24 m | ||||||||||
| Power plant output: | 1320 MW | ||||||||||
| Data on the reservoir | |||||||||||
| Water surface | 5 580 km² | ||||||||||
| Reservoir length | 280 km | ||||||||||
| Reservoir width | 32 km | ||||||||||
| Storage space | 180.60 km³ | ||||||||||
| Catchment area | 520 000 km² | ||||||||||
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The Kariba dam ( English Kariba Dam ) is a large dam in the Kariba Gorge of the Zambezi along the border of Zambia and Zimbabwe in southern Africa . The facility is managed by a bi-national authority, the Zambezi River Authority .
Dam wall
The dam has a double curved arch dam of concrete and was built between 1955 and 1959th Construction of the actual dam wall began on November 6, 1956. It is 128 m high and 617 m long with a wall volume of 1,032,000 m³. The foundation is 24 m thick. The hydropower plant , which went into operation in 1959, has a capacity of 1320 MW and supplies the copper belt of Zambia and Zimbabwe with 6400 (or 6700) GWh per year. The construction costs for the first construction phase with the Kariba-Süd power station cavern amounted to 135 million US dollars. The Kariba-Nord power station cavern was not completed until 1977 because of major political problems. The total construction cost was $ 480 million. Around 100 workers died in accidents during the construction work.
The crown of the dam is used for a regional road that can be used to cross the Zambezi.
Reservoir
The Kariba reservoir ( Lake Kariba in English ) is - according to the list of the largest reservoirs on earth - the second largest in terms of volume and fifth largest in terms of area. It is 280 km long, its average width is 18 km and it is about 29 m deep on average. Its maximum depth is 97 m. It has a maximum of 5580 km² of water surface and a storage capacity of 180.60 km³ (= 180,600,000,000 m³). The catchment area is 520,000 km². Between 20,000 and 30,000 tons of Lake Tanganyika sardines are fished in the lake every year . The Innscor company also operates a few crocodile farms here .
When the reservoir was filled, it was initially called Elizabeth II Lake , after the reigning British Queen, and was only later renamed "Karibasee".
Tributaries
A large number of smaller rivers flow into the reservoir. The largest, apart from the Zambezi, is by far the Sanyati from the southeast. The next larger is the Sengwa , coming from the south , followed by the Umi, also coming from the south . However, all three only add water to the lake during the rainy season, if at all, as their headwaters are in arid areas.
Resettlement
When the Kariba reservoir was filled, about 57,000 people who lived on the Zambezi had to be relocated. From 1960 to 1961, around 6000 large animals and countless small animals were captured in Operation Noah and also relocated because they were threatened by the rising water.
earthquake
Since its filling, the Kariba reservoir has caused numerous earthquakes due to its weight ( induced seismicity ). 20 of them were greater than magnitude 5 on the Richter scale , the largest was in 1963 with magnitude 5.8. Its epicenter was 50 km north of the dam. Engineers and seismologists are still unsure of the exact mechanisms, but the effect of 180 billion tons of water weight is considerable. The Zambezi Valley itself experienced an earthquake measuring 6 on the Richter scale in 1910, before the dam was built. A systematic recording of seismic movements has only existed since the dam was built. Such movements are normal when a reservoir is being filled. They subside over time.
Redevelopment
The building, which is getting on in years, needs a refurbishment decided on in September 2015, which is to cost 294 million US dollars and is financed by the EU , the World Bank , the African Development Bank and Sweden . On the one hand, the concrete of the dam swells due to chemical decomposition, on the other hand, the scouring of the water falling over the flood relief system deepened the stilling basin from originally ten meters to 90 meters, which endangers the foundation of the structure. The renovation work should take ten years.
If the dam breaks, it is expected that over 8 to 10 hours the water from the reservoir will pour into the valley below, threatening 3.5 million people in Zimbabwe, Zambia, Malawi and Mozambique . It is also assumed that the downstream Cahora-Bassa dam would fail in the event of a dam failure.
See also
- Zambia Electricity Supply Corporation
- List of the largest dams on earth
- List of the largest reservoirs on earth
- List of the largest hydroelectric plants in the world
- List of dams in the world
literature
- Julia Tischler : Light and Power for a Multiracial Nation. The Kariba Dam Scheme in the Central African Federation. Palgrave Macmillan (2013).
Web links
Individual evidence
- ↑ South African History online : November 6th , accessed on November 5th, 2011
- ↑ a b c Kariba dam a ticking time-bomb. In: The Citizen. Retrieved October 18, 2015 .
- ↑ a b US $ 294 million funds emergency repairs at 1,830-MW Kariba hydroelectric facility. In: www.hydroworld.com. Retrieved October 18, 2015 .