The Cahora Bassa lake—in the Portuguese colonial era (until 1974) known as Cabora Bassa, from Nyungwe ''Kahoura-Bassa'', meaning "finish the job"—is

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

's fourth-largest artificial lake, situated in the

Tete Province Tete is a province of Mozambique. It has an area of 98,417 km² and a population of 2,648,941 (2017 census). Tete is the capital of the province. The Cahora Bassa Dam is situated in this province. Districts On March 21, 2013, Mozambi ...

Mozambique Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi ...

. In Africa, only Lake Volta in Ghana,

Lake Kariba Lake Kariba is the world's largest artificial lake and reservoir by volume. It lies upstream from the Indian Ocean, along the border between Zambia and Zimbabwe. Lake Kariba was filled between 1958 and 1963 following the completion of the Karib ...

, on the Zambezi upstream of Cahora Bassa, and

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Medit ...

's Lake Nasser are bigger in terms of surface water.

History

Portuguese period

The Cahora Bassa System started in the late 1960s as a project of the

Portuguese Portuguese may refer to: * anything of, from, or related to the country and nation of Portugal ** Portuguese cuisine, traditional foods ** Portuguese language, a Romance language *** Portuguese dialects, variants of the Portuguese language ** Portu ...

in the Overseas Province of Mozambique.

Southern Africa Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number o ...

n governments were also involved in an agreement stating that Portugal would build and operate a hydroelectric generating station at Cabora Bassa (as it was then called in

) together with the high-voltage direct current (HVDC) transmission system required to bring electricity to the border of South Africa.

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...

, on the other hand, undertook to build and operate the Apollo converter station and part of the transmission system required to bring the electricity from the South African/Mozambican border to the Apollo converter station near

Pretoria Pretoria () is South Africa's administrative capital, serving as the seat of the executive branch of government, and as the host to all foreign embassies to South Africa. Pretoria straddles the Apies River and extends eastward into the foot ...

. South Africa was then obliged to buy electricity that Portugal was obliged to supply. During the struggle for independence, construction materials for the dam were repeatedly attacked in a strategic move by

Frelimo FRELIMO (; from the Portuguese , ) is a democratic socialist political party in Mozambique. It is the dominant party in Mozambique and has won a majority of the seats in the Assembly of the Republic in every election since the country's firs ...

guerrillas, as its completion would cause the lake to widen so much it would take very long to cross to the other side with their canoes. The dam began to fill in December 1974, after the Carnation Revolution in

mainland Portugal Continental Portugal ( pt, Portugal continental, ) or mainland Portugal comprises the bulk of the Portuguese Republic, namely that part on the Iberian Peninsula and so in Continental Europe, having approximately 95% of the total population and 9 ...

and the independence agreement has been signed. Mozambique officially became independent from Portugal on 25 June 1975. Until November 2007, the dam was operated by ''Hidroeléctrica de Cahora Bassa'' (HCB) and jointly owned by Mozambique, with an 18% equity stake, and

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...

, which held the remaining 82% equity. On 27 November 2007, Mozambique assumed control of the dam from Portugal, when Portugal sold to Mozambique most of its 82 percent stake. Finance Minister Fernando Teixeira dos Santos said Portugal would collect US$950 million (€750 million) from the sale of its part of southern Africa's largest hydropower project. Portugal kept a 15 percent stake, though it planned to sell off another 10 percent at a later stage to an investor that would be proposed by the Mozambican government. Portugal's Prime Minister,

José Sócrates José Sócrates Carvalho Pinto de Sousa, GCIH (born 6 September 1957), commonly known as José Sócrates (), is a Portuguese politician who was the prime minister of Portugal from 12 March 2005 to 21 June 2011. For the second half of 2007, he ...

, signed the agreement with the Mozambican government, during an official visit to

Maputo Maputo (), formerly named Lourenço Marques until 1976, is the capital, and largest city of Mozambique. Located near the southern end of the country, it is within of the borders with Eswatini and South Africa. The city has a population of 1,0 ...

. The agreement ended decades of dispute between Portugal and its former territory over the company, called ''Hidroeléctrica de Cahora Bassa''. The central disagreement was over the handling of the company's estimated US$2.2 billion (€1.7 billion) debts to Portugal. Mozambican authorities argued they had not guaranteed the debt and therefore should not be liable for the payments.

Independent Mozambique

Mozambique became independent from Portugal on 25 June 1975. Since closure, the Zambezi, which is the fourth largest floodplain river in Africa, has received a far more regulated flow rate, but disastrous natural 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". For further details of ecological problems caused by the dam, see the article on the

Zambezi River The Zambezi River (also spelled Zambeze and Zambesi) is the fourth-longest river in Africa, the longest east-flowing river in Africa and the largest flowing into the Indian Ocean from Africa. Its drainage basin covers , slightly less than hal ...

. During the

Mozambican Civil War The Mozambican Civil War ( pt, Guerra Civil Moçambicana) was a civil war fought in Mozambique from 1977 to 1992. Like many regional African conflicts during the late twentieth century, the Mozambican Civil War possessed local dynamics but was a ...

(1977–1992) the transmission lines were sabotaged to the extent that 1,895 towers needed to be replaced and 2,311 refurbished over a distance of 893 km on the Mozambican side of the line. In the 1990s, after the end of the civil war, ''Hidroeléctrica de Cahora Bassa'' (HCB) appointed South Africa's Trans-Africa Projects (TAP) to perform the construction management, quality assurance and design support service for the rehabilitation of the project. TAP assisted HCB in awarding the construction contract to a joint venture company comprising Consorzio Italia 2000 and

Enel Enel S.p.A. is an Italian multinational manufacturer and distributor of electricity and gas. Enel, which originally stood for Ente nazionale per l'energia elettrica (National Electricity Board), was first established as a public body at the ...

, and a scheduled period of 24 months was set for the project. The lines in South Africa were damaged to a minor extent and only normal maintenance was required by

Eskom Eskom Hld SOC Ltd or Eskom is a South African electricity public utility. It was established in 1923 as the Electricity Supply Commission (ESCOM) and was also known by its Afrikaans name Elektrisiteitsvoorsieningskommissie (EVKOM). Eskom repre ...

to get these lines back in operation. Work on the project started in August 1995. The line route in Mozambique passes through dense bush and difficult terrain from Songo to the South African border near

Pafuri The Makuleke Contractual Park or Pafuri Triangle constitutes the northernmost section of the Kruger National Park, South Africa, and comprises approximately 240 square kilometres of land. The "triangle" is a wedge of land created by the confluenc ...

, with both servitudes infested with landmines from the

(1977–1992) that needed to be cleared before construction work could commence. Heavy, unseasonable rainfalls later affected the programme to such an extent that the first line could only be completed in August 1997 and the second in November that same year. During the refurbishment period, TAP developed and implemented various designs and construction methods to improve the overall programme schedules and project costs. In spite of the extreme conditions within which they had to refurbish and reconstruct these lines, the work was completed within schedule and with a limited budget. The lines have, since completion, been subject to numerous tests and energised to its full potential. About 1,100 people were employed during the peak periods of construction. The rainfalls and severe flooding during February 2000 in the

Limpopo River The Limpopo River rises in South Africa and flows generally eastward through Mozambique to the Indian Ocean. The term Limpopo is derived from Rivombo (Livombo/Lebombo), a group of Tsonga settlers led by Hosi Rivombo who settled in the mountain ...

valley again caused considerable damage to both lines to the extent that about 10 towers collapsed and need to be reconstructed within the shortest possible timeframe to restore the power supply to South Africa. TAP was again entrusted by HCB with the engineering, procurement and construction management services. TAP managed to temporarily restore power supply through the one line while a more permanent solution could be carried out on the other line. The reconstructed line is used to carry the full line capacity. TAP had to implement unconventional construction techniques to recover temporary supply. The suspension towers next to the river crossing posed a significant challenge for a temporary power solution to obtain the required clearances of the 711 metre level terrain span. On April 27, 2009 four foreign nationals were arrested for putting a "highly corrosive" substance into the lake in an alleged attempt to sabotage the power station. The arrested claimed to be a team from Orgonise Africa, placing orgonite pieces in the lake to improve the quality of etheric energy (life force) of the dam. Since 2005, the area is considered a Lion Conservation Unit.IUCN Cat Specialist Group (2006). Conservation Strategy for the Lion ''Panthera leo'' in Eastern and Southern Africa. IUCN, Pretoria, South Africa.

Related economic activities

Most of the electricity generated by Cahora Bassa, which is located on the Zambezi River in western Mozambique, is sold to nearby South Africa. In 2006, Cahora Bassa transmitted about 1,920 megawatts of power, but the infrastructure is capable of higher production levels and the company had plans to almost double its output by 2008. In 1994 the total installed capacity in Mozambique was 2,400 MW of which 91% was hydroelectric. A considerable

kapenta The Tanganyika sardine is known as kapenta or matemba in Zambia, Malawi and Zimbabwe (a related but different fish known as dagaa or ndaga is ''Rastrineobola argentea''). Kapenta is two species ( Lake Tanganyika sardine, ''Limnothrissa miodon'' ...

fishery has developed in the reservoir. The kapenta is assumed to originate from

where it was introduced from Lake Tanganyika. Annual catch of kapenta in the Cahora Bassa dam in 2003 exceeded 10,000 tonnes. It is widely believed that there is a breeding colony of Zambezi sharks "trapped" inside the dam. As the

bull shark The bull shark (''Carcharhinus leucas''), also known as the Zambezi shark (informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in ri ...

is known to travel more than 100 km upstream, this phenomenon does not conflict with existing scientific and biological fact. Usually an ocean-dwelling species, bull sharks are perfectly capable of living in fresh water for their entire lifespan. Local tribes have indeed reported sightings (and attacks) by this isolated community of shark, although these have yet to be substantiated with hard evidence.

References

External links