Cahora Bassa
Encyclopedia
The Cahora Bassa lake is Africa
's fourth-largest artificial lake, situated in the Tete Province
in Mozambique
. The name Cabora Bassa is an earlier misspelling of the name. In Africa, only Lake Volta
in Ghana, Lake Kariba
, on the Zambezi upstream of Cahora Bassa, and Egypt
's Lake Nasser
are bigger in terms of surface water.
in the Overseas Province of Mozambique. South Africa
n Governments were also involved in an agreement stating that Portugal would build and operate a hydroelectric generating station at Cahora Bassa together with the high-voltage direct current (HVDC) transmission system required to bring electricity to the border of South Africa. South Africa, 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 Midrand. South Africa was then obliged to buy electricity that Portugal was obliged to supply.
During its construction, the dam site was repeatedly attacked without success by Frelimo guerrilla insurgents in an attempt to sabotage the project. Portugal increased popular support in Mozambique with this and other development works (see Mozambican War of Independence
). The dam began to fill in December 1974.
Until 2007 the dam was operated by Hidroeléctrica de Cahora Bassa and jointly owned by Mozambique, with an 18% equity stake, and Portugal
, which held the remaining 82% equity. On November 27, 2007 Mozambique assumed control of the dam from Portugal. In 2007, Portugal sold to Mozambique most of its 82 percent stake in the Cahora Bassa hydroelectric power facility in the Southeast African country. 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 keeps a 15 percent stake in Cahora Bassa, 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
signed the agreement with the Mozambican government, during an official visit to Maputo
. The agreement ended decades of dispute between Portugal and its former territory in East Africa
over the company, called Hidroelectrica 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.
Mozambique became independent from Portugal in 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.
During the Mozambican Civil War
(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, Hidroelectrica 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
, 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
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, with both servitudes infested with landmines from the Mozambican Civil War
(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
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 a team from Orgonise Africa, placing Orgonite pieces in the lake to improve the quality of etheric energy (life force) of the dam.
A considerable kapenta
fishery has developed in the reservoir. 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.
It is widely believed that there is a breeding colony of Zambezi Shark "trapped" inside the dam.
As the Bull Shark
is known to travel >100 km upstream, this phenomenon does not conflict with
existing scientific and biological fact. In particular 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.
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
's fourth-largest artificial lake, situated in the Tete Province
Tete Province
Tete is a province of Mozambique. It has an area of 100,724 km² and a population of approximately 1.551.949 .Tete is the capital of the province...
in Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...
. The name Cabora Bassa is an earlier misspelling of the name. In Africa, only Lake Volta
Lake Volta
Lake Volta is the largest reservoir by surface area in the world, and the fourth largest one by water volume. It is located completely within the country of Ghana, and it has a surface area of about 8,502 km² . Lake Volta lies along the Greenwich Meridian, and just six degrees of latitude...
in Ghana, Lake Kariba
Lake Kariba
Lake Kariba is the world's largest artificial lake and reservoir. It lies 1300 kilometers upstream from the Indian Ocean, along the border between Zambia and Zimbabwe...
, on the Zambezi upstream of Cahora Bassa, and Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
's Lake Nasser
Lake Nasser
Lake Nasser is a vast reservoir in southern Egypt, and northern Sudan, and is one of the largest man-made lakes in the world. Strictly, "Lake Nasser" refers only to the much larger portion of the lake that is in Egyptian territory , with the Sudanese preferring to call their smaller body of water...
are bigger in terms of surface water.
Portuguese period
The Cahora Bassa System started in the late 1960s as a project of the PortuguesePortugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
in the Overseas Province of Mozambique. South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
n Governments were also involved in an agreement stating that Portugal would build and operate a hydroelectric generating station at Cahora Bassa together with the high-voltage direct current (HVDC) transmission system required to bring electricity to the border of South Africa. South Africa, 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 Midrand. South Africa was then obliged to buy electricity that Portugal was obliged to supply.
During its construction, the dam site was repeatedly attacked without success by Frelimo guerrilla insurgents in an attempt to sabotage the project. Portugal increased popular support in Mozambique with this and other development works (see Mozambican War of Independence
Mozambican War of Independence
The Mozambican War of Independence was an armed conflict between the guerrilla forces of the Mozambique Liberation Front or FRELIMO , and Portugal...
). The dam began to fill in December 1974.
Until 2007 the dam was operated by Hidroeléctrica de Cahora Bassa and jointly owned by Mozambique, with an 18% equity stake, and Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
, which held the remaining 82% equity. On November 27, 2007 Mozambique assumed control of the dam from Portugal. In 2007, Portugal sold to Mozambique most of its 82 percent stake in the Cahora Bassa hydroelectric power facility in the Southeast African country. Finance Minister Fernando Teixeira dos Santos
Fernando Teixeira dos Santos
Fernando Teixeira dos Santos , GOIH is a Portuguese economist and professor. He was Minister of Finance in the Portuguese Government led by José Sócrates .-Career:...
said Portugal would collect US$950 million (€750 million) from the sale of its part of southern Africa's largest hydropower project. Portugal keeps a 15 percent stake in Cahora Bassa, 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
José Sócrates Carvalho Pinto de Sousa, GCIH , commonly known by José Sócrates , is a Portuguese politician who was the Prime Minister of Portugal from 12 March 2005 to 21 June 2011....
signed the agreement with the Mozambican government, during an official visit to Maputo
Maputo
Maputo, also known as Lourenço Marques, is the capital and largest city of Mozambique. It is known as the City of Acacias in reference to acacia trees commonly found along its avenues and the Pearl of the Indian Ocean. It was famous for the inscription "This is Portugal" on the walkway of its...
. The agreement ended decades of dispute between Portugal and its former territory in East Africa
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
over the company, called Hidroelectrica 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
During the Mozambican Civil War
Mozambican Civil War
The Mozambican Civil War began in 1977, two years after the end of the war of independence. The ruling party, Front for Liberation of Mozambique , was violently opposed from 1977 by the Rhodesian- and South African-funded Mozambique Resistance Movement...
(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, Hidroelectrica 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
Enel may refer to:*Enel SpA, an Italian electricity company*Enel , a fictional villain in the One Piece manga and anime series*Enel, meaning third in the fiction of J. R. R. Tolkien, cf. Awakening of the Elves...
, 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
Eskom is a South African electricity public utility, established in 1923 as the Electricity Supply Commission by the government of South Africa in terms of the Electricity Act . It was also known by its Afrikaans name Elektrisiteitsvoorsieningskommissie . The two acronyms were combined in 1986 and...
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
Songo
Songo may refer to:* Songo music, a type of contemporary Cuban music originating in Havana* Songo people, of northern Angola* Songo-salsa, a style of music that blends Spanish rapping and hip hop beats with salsa music and songo- Places :...
to the South African border near Pafuri, with both servitudes infested with landmines from the Mozambican Civil War
Mozambican Civil War
The Mozambican Civil War began in 1977, two years after the end of the war of independence. The ruling party, Front for Liberation of Mozambique , was violently opposed from 1977 by the Rhodesian- and South African-funded Mozambique Resistance Movement...
(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
Limpopo River
The Limpopo River rises in central southern Africa, and flows generally eastwards to the Indian Ocean. It is around long, with a drainage basin in size. Its mean annual discharge is 170 m³/s at its mouth...
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 a team from Orgonise Africa, placing Orgonite pieces in the lake to improve the quality of etheric energy (life force) of the dam.
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
Kapenta
The Tanganyika sardine, known as Kapenta in Zambia and Zimbabwe or Dagaa or Ndgaa elsewhere, is really two species both of which are small, planktivorous, pelagic, freshwater clupeid originating from Lake Tanganyika in East Africa...
fishery has developed in the reservoir. The kapenta is assumed to originate from Lake Kariba
Lake Kariba
Lake Kariba is the world's largest artificial lake and reservoir. It lies 1300 kilometers upstream from the Indian Ocean, along the border between Zambia and Zimbabwe...
where it was introduced from Lake Tanganyika
Lake Tanganyika
Lake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, after Lake Baikal in Siberia; it is also the world's longest freshwater lake...
. Annual catch of kapenta in the Cahora Bassa dam in 2003 exceeded 10 thousand tons.
It is widely believed that there is a breeding colony of Zambezi Shark "trapped" inside the dam.
As the Bull Shark
Bull shark
The bull shark, Carcharhinus leucas, also known as Zambezi shark or unofficially known as Zambi in Africa and Nicaragua shark in Nicaragua, is a shark common worldwide in warm, shallow waters along coasts and in rivers...
is known to travel >100 km upstream, this phenomenon does not conflict with
existing scientific and biological fact. In particular 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.
See also
- 2007 Mozambican flood2007 Mozambican floodThe 2007 Mozambican flood began in late December 2006 when the Cahora Bassa Dam overflowed from heavy rains on Southern Africa. It worsened in February 2007 when the Zambezi River broke its banks, flooding the surrounding areas in Mozambique...
- Cahora Bassa (HVDC) for details of the power scheme based on the dam.
General references
- Hidroeléctrica de Cahora Bassa (HCB) Website (Portuguese)
- World Lake Database for facts and figures
- Cahora Bassa, Encyclopedia Britannica.
- Allen Isaacman and Chris Sneddon, "Portuguese Colonial Intervention, Regional Conflict and Post-Colonial Amnesia: Cahora Bassa Dam, Mozambique 1965–2002," Conference on Lusophone Africa: Intersections between the Social Sciences http://www.kyle.aem.cornell.edu/Lusoconferencepage.htm, Cornell Institute for African Development (May 2003).